Digitized by the Internet Archive
in 2011 with funding from
Open Knowledge Commons and Harvard Medical School
http://www.archive.org/details/anatomydescripti1878gray
ANATOMY,
DESCRIPTIYE AND SURGICAL
BY
HENRY GRAY, F.R.S.,
FELLOW OF THE ROYAL COLLEGE OF SUKGEONS AND LECTURER ON
ANATOMY AT ST. GEORGE'S HOSPITAL MEDICAL SCHOOL.
WITH FIVE HUNDRED AND TWENTY-TWO ENGRAVINGS ON WOOD.
THE DRAWIIS'GS BY H. Y. CARTER, M. D., A.^!) DR. WESTMACOTT.
THE DISSECTIONS JOINTLY BY THE AUTHOR AKD DK. CARTER.
WITH AN INTRODUCTION ON GENERAL ANATOMY AND DEVELOPMENT.
BY
T. HOLMES, M.A. Cantab.,
SURGEON TO ST. GEORGE'S HOSPITAL; MEM. COERESP. DE LA SOC. DE CHIR. DE PARIS.
A NEW AMERICAN
FROM THE
EIGHTH AND ENLARGED ENGLISH EDITION.
TO WHICH IS ADDED
LANDMARKS, MEDICAL AND SURGICAL.
By LUTHER HOLDEN, F.E.O.S.,
SUKGEON TO ST. BARTHOLOMEW'S AND THE FOUNDLING HOSPITALS.
PHILADELPHIA:
HElvTET O. LEA.
1878.
Entered according to Act of Congress in the year 1878, by
HENRY C. LEA,
in the Office of the Librarian of Congress. All rights reserved.
COLLINS, PRINTER
TO
SIR BENJAMIN COLLINS BRODIE, BART., F.R.S., D.C.L.,
SERJEANT-SURGEON TO THE QUEEN,
CORRESPONDING MEMBER OE THE INSTITUTE OF FRANCE,
IN ADMIRATION OF
HIS GREAT TALENTS,
AND IN REMEMBRANCE OP
MANY ACTS OF KINDNESS SHOWN TO THE AUTHOR
FROM AN
EARLY PERIOD OF HIS PROFESSIONAL CAREER.
(iii)
AMERICAN PUBLISHER'S NOTICE.
The present edition, like the previons American reprints, has
been passed throngh the press under the supervision of Dr.
RiCHAED J. DuNGLisoN. As the work has had the advantage of
three revisions at the hands of tlie distinguished editor, Mr. Holmes,
since tlie appearance of the last American edition, no necessity has
been found for the insertion of additional details, but Dr. Duistgli-
so]^ has carefully corrected whatever errors had escaped attention
in England, and has made such changes in the typographical
arrangement as seemed calculated to render the volume more con-
venient for consultation and reference. A few illustrations have
also been inserted in the introductory section. They will be found
distinguished by inclosure in brackets.
The recent work of Mr. Holder" — "Landmarks, Medical an^d
SueGtICAl" — has attracted so much attention, as affording, within
brief compass, exactly the information required by practitioners in
the application of anatomical knowledge, that the jDublisher has
hoped, by appending it, to render the volume still more acceptable
to those for whose use it is intended.
riilLADELPiilA, June, 18*78.
(iv)
PREFACE TO THE EIGHTH EDITION.
The only changes made in this Edition have been such alterations
in the sections on Microscopical Anatomy and on Development as
the ever-increasing activity of research in those branches of the
science has seemed to require. Some illustrations which appeared
necessary for the further elucidation of the text have been borrowed,
with i)ermission, from well-known text-books, such as Frey's
"Histology," Strieker's "Handbook," and Quain's "Anatomy."
PREFACE TO THE SEVENTH EDITION.
This Edition has received a most careful revision both of the text
and of the sections on Visceral Anatomy. In the former depart-
ment of the work the editor has to acknowledge the very valuable
assistance received from his friend. Professor Daelii^g, of ^ew
York Univei-sity, w^ho has been so kind as to communicate to him
all the verbal and other errors which he has noted in the course of
several years during which he has used " G-ray's Anatomy" as the
text-book for his class. Eor other assistance the Editor is indebted
to his former pupil, Mr. E. J. Spitta, late Demonstrator of
Anatomy at the School of St. George's Hospital, by whom the
(^)
vi PEEFACE TO THE SEVENTH EDITION.
section on the Anatomy of the Xidney m the present edition has
been enth^ely re- written.
The illustrations which have been incorporated in this edition
from the "Handbook for the Physiological Laboratory" are from
original drawings by Dr. Kleix.
18 Great Cumberland Place:
December, 1874.
PREFACE TO THE SIXTH EDITION.
IjST this edition the old description of the Cochlea, which had been
allowed to remain uncorrected by an oversight, has been modified so
as to embrace the essential points of recent discoveries in the struc-
ture of the internal ear. For the figures illustrating this descrip-
tion the Editor is indebted to his friend, Mr. C, Stewaet, Curator
of the Museum of St. Thomas's Hospital, as well as for one to
replace an erroneous diagram of the minute structure of the large
intestine.
The account of the actions of some of the larger joints has also
been made somewhat fuller; a few new figures have been added,
and the errors of the press have been still further corrected.
In other respects this Edition is a reprint of the former.
31 Clarges Street, July, 1872.
PREFACE TO THE FIRST EDITION.
This work is intended to furnisla tlie Student and Practitioner with an accu-
rate view of tlie Anatomy of the Human Body, and more especially the appli-
cation of this Science to Practical Surgery.
One of the chief objects of the Author has been, to induce the "Student to
apply his anatomical knowledge to the more practical points in Surgery, by
introducing, in small type, under each subdivision of the work, such observa-
tions as show- the necessity of an accurate knowledge of the part under exami-
nation.
Osteology. Much time and care have been devoted to this part of the work,
the basis of anatomical knowledge. It contains a concise description of the
anatomy of the bones, illustrated by numerous accurately-lettered engravings
showing the various markings and processes on each bone. The attachments
of each muscle are shown in dotted lines (after the plan recently adopted by
Mr. Holden), copied from recent dissections. The articulations of each bone
are shown on a new plan ; and a method has been adopted, by which the hitherto
complicated account of the development of the bones is made more simple.
The Articulations. In this section, the various structures forming the joint
are described ; a classification of the joints is given ; and the anatomy of each
carefully described : abundantly illustrated by engravings, all of which are
taken from, or corrected by, recent dissections.
The Muscles and Fascise. In this section, the muscles are described in groups,
as in ordinary anatomical works. A series of illustrations, showing the lines
of incision necessary in the dissection of the muscles in each region, are intro-
duced, and the muscles are shown in fifty-eight engravings. The Surgical
Anatomy of the muscles in connection with fractures, of the tendons or muscles
divided in operations, is also described and illustrated.
The Arteries. The course, relations, and Surgical Anatomy of each artery
are described in this section, together with the anatomy of the regions contain-
ing the arteries more especially involved in surgical operations. This part of
the work is illustrated by twenty-eight engravings.
(vii)
viii PREFACE TO THE FIRST EDITION.
Tlie Veins are described as in ordinary anatomical works ; and illustrated by
a series of engravings, showing tliose in each, region. The veins of the spine
are described and illustrated from the well-known work of Breschet.
The Lymphatics are described, and figured in a series of illustrations copied
from the elaborate work of Mascagni.
The Nervous System and Organs of Sense. A concise and accurate descrip-
tion of this important part of anatomy has been given, illustrated by sixty-six
engravings, showing the spinal cord and its membranes ; the anatomy of the
brain, in a series of sectional views; the origin, course, and distribution of the
cranial, spinal, and sympathetic nerves ; and the anatomy of the organs of sense.
The Viscera. A detailed description of this essential part of anatomy has
been given, illustrated by fifty-iive large, accurately lettered engravings.
Begional Anatomy. The anatomy of the perineum, of the ischio-rectal region
and of femoral and inguinal hernise, is described at the end of the work ; the
region of the neck, the axilla, the bend of the elbow, Scarpa's triangle, and the
popliteal space, in the section on the arteries ; the laryngo-tracheal region, with
the anatomy of the trachea and larynx. The regions are illustrated by many
engravings.
Microscopical Anatomy. A brief account of the microscopical anatomy of
some of the tissues, and of the various organs, has also been introduced.
The Author gratefully acknowledges the great services he has derived in the
execution of this work, from the assistance of his friend. Dr. H. Y. Carter, late
Demonstrator of Anatomy at St. George's Hospital. All the drawings from
which the engravings were made, were executed by him. In the majority of
cases, they have been copied from, or corrected by, recent dissections made
jointly by the Author and Dr. Carter.
The Author has also to thank his friend, Mr. T. Holmes, for the able assist-
ance afforded him in correcting the proof-sheets in their passage through the
press.
The engravings have been executed by Messrs. Butterworth and Heath ; and
the Author cannot omit thanking these gentlemen for the great care and fidelity
displayed in their execution.
Wir.TON Street, Eelgrate Square :
August 1858.
CONTENTS.
INTRODUCTION; General Anatomy.
The Blood
PASB
So
Lymph and Chyle
37
Cells and Protoplasm
38
Cellular and Fibrous Tissue
39
Adipose Tissue ....
41
Pigment
43
Cartilage .....
43
Fibro-cartilage
45
YeUow or Reticular Cartilage .
46
Bone ......
46
Development of Bone
51
Muscular Tissue ....
56
Nervous Tissue ....
60
The Brain ....
64
The Spinal Cord ....
66
The Ganglia ....
68
The Nerves ....
68
The Sympathetic Nerve .
70
Terminations of Nerves
70
The Vascular System
75
The Ai-teries ....
75
The Capillaries
78
The Veins _.
78
The Lymphatics
81
The Lymphatic Glands
82
The Skin and its Appendages .
83
The Nails . . " .
87
The Hairs ....
87
The Sebaceous Glands
88
The Sudoriferous Glands .
89
The Epithelium ....
90
Serous, Synovial, and Mucous Membrane
3 92
Secreting Glands ....
93
Growth and Development of the Body
94
Fecundation of the Ovum
95
Division of Blastodermic Membrane
96
Formation of Germinal Ai-ea anc
Chorda Doi'salis .
98
Parts formed from each layer of th(
Blastodermic Membrane
98
The Amnion ....
101
The Allantois ....
102
The Umbilical Vesicle
102
The Chorion ....
. 102
Tlie Decidua ....
. 104
The Placenta ....
104
The Umbilical Cord
104
Growth of the Embryo
105
Development of the Various Parts .
106
The Spine ....
106
The Cranium and Face
108
The Palate ....
110
The Brain ....
110
The Spinal Marrow and Nerves
112
The Eye
113
The Ear
114
The Nose ....
115
The Skin, Glands, and Soft Parts
115
The Limbs and Muscles .
116
The Heart ....
116
The Blood Corpuscles and Vessels
117
The Alimentary Canal and its Appen-
dages .....
120
The Respiratory Organs .
122
The Genito-urinary Organs
122
The Wolffian Body .
123
The Internal Genital Organs : .
Female ....
124
Male ....
126
The External Genital Organs : .
Indifferent Type
127
Female Organs .
127
Male Organs
128
Chronological Table of the Developmen
t
of the Foetus . . .
129
DESCRIPTIVE AND SURGICAL AJSTATOMY.
Osteology.
The Skeleton . . . .
Number of the Bones . . .
Form of Bones . . . .
The Spine.
General Characters of a Vertebra
Characters of the Cervical Vertebrae
Atlas ......
131
131
131
132
133
134
Axis
Vertebra Prominens
Cliaracters of the Dorsal Vertebras .
Peculiar Dorsal Vertebrae
Characters of the Lumbar Vertebras
Structure of the Vcrtebrje
Development of the Vertebrte
Progress of Ossification in the Spine
(ix)
135
136
137
138
139
140
140
141
CONTENTS.
Sacral and Coccygeal Vertebrte
Sacrum .....
Coccyx .....
Of the Spine in general .
The Skull.
Bones of the Cranium
OccijDital Bone
Parietal Bones
Frontal Bone .
Temporal Bones
Sphenoid Bone
Ethmoid Bone .
Development of the Cranium
The Fontanelles
Wormian Bones
Congenital Fissures and Gaps
Bones of tihe Face :
Nasal Bones
Superior Maxillary Bones
Lachrymal Bones
IMalar Bones
Palate Bones .
Inferior Turbinated Bones
Vomer ....
Inferior Maxillary Bone .
Changes j^roduced in the Lower Jaw
by age ....
Sutin-es of the Skull
Vertex of the Skull
Base of the Skull, Internal Surface
Anterior Fossa
Middle Fossa .
Posterior Fossa
Base of Skull, External Surface
Lateral Region of the Skull
Temporal Fossa
Zygomatic Fossa
Spheno-maxillary Fossa .
Anterior Region of the SlcuU .
Orbits .....
l^asal Fossaj ....
Os Hyoides ....
The Thorax.
The Sternum
The Ftibs
PASE
142
143
14G
147
149
150
154
156
159
1G5
170
172
172
173
173
174
175
179
ISO
182
184
185
186
190
190
192
192
192
194
195
195
199
199
200
200
201
202
203
206
207
210
PAGB
Peculiar Ribs 212
Costal Cartilages . . . . .214
The Upper Extremity.
The Shoulder 215
The Clavicle 215
The Scapula 218
The Humerus . . . . . .223
The Ulna 228
The Radius 233
The Hand 235
The Carpus . . . . . .235
Bones of the Upper Row . . .236
Bones of the Lower Row . . . 238
The Metacarpus . . . . .241
Peculiar Characters of the ]\Ietacarpal
Bones 241
Phalanges 243
Development of the Bones of the Hand . 244
T'he Lower Extremity.
Os Innominatum . . . . .245
Ilium 247
Ischium ...... 248
Pubcs .249
Development of the Os Innominatum . 251
The Pelvis . . . . . .251
Differences between the Male and Female
Pelvis 254
Thfe Femur ...... 254
The Leg ...... 260
Patella 260
Tibia 262
Fibula . 265
The Foot 267
Tarsus 267
Os Calcis . . . . . .267
Cuboid 269
Astragalus . . . . . .270
Scaphoid 272
Internal Cuneiform . . . . .272
Middle Cuneiform 273
External Cuneiform . . . .273
Metatarsal Bones . . . . .274
Phalanges . . . . . .275
Development of the Bones of the Foot . 276
Sesamoid Bones . . . . .276
The Articulations.
Structures composing the Joints
279
Articular Lamella of Bone
279
Ligaments ....
279
Synovial Membrane .
279
Bursai . . . .
280
Synovia .....
280
Forms of Articulation :
Synarthrosis ....
280
Aniphiatlirosis ....
281
Diarthrosis ....
281
Movements of Joints
284
Articulations of the Trunk.
Articulations of the Vertebral Column
. 285
Atlas with the Axis
288
Spine with the Cra.-
niiim
291
Articulations of tlie Atlas with the Occipi-
tal Bone
Axis with the Occipi-
tal Bone
Temporo-maxillary Articulation
Articulations of the Ribs with the Verte-
brae :
Costo-vertebral ....
Costo-transverse ....
Articulations of the Cartilages of the Ribs
with the Sternum and Ensiibrm Cai'ti-
lage
Tntercostid Articulations ....
ivigaments of the Sternum
Articulation of the Pelvis with the Spine .
vVrticulation of the Sacrum and Ilium
Ligaments between the Sacrum and Is-
chium . , . . ,
291
292
292
295
296
297
299
299
299
300
301
CONTENTS.
Articulation of tlie Sacrum and Coccyx
PAGB
302
Articulation of the Pubes
303
Articulations of the Upper Extremity.
Sterno-clavicular ....
304
Scapulo-clavicular .
306
Proper Ligaments of the Scapula
307
Shoulder-joint . . .
308
Elbow-joint ....
310
Radio-ulnar Articidations
313
"Wrist-joint ....
315
Articulations of the Carpus
316
Carpo- metacarpal Articulations
319
PAGE
Metacarpo-phalangeal Articulations . .321
Articulations of the Phalanges . .322
Articulations of the Lower Extremitij.
Hip-joint 322
Knee-joint . . . . . .325
Articulations between the Tibia and Fibula 330
Ankle-joint . . . . . .331
Articulations of the Tarsus . . .334
Tarso-metatarsal Articulations . .337
Articulations of the Metatarsal Bones . 338
Metatarso-phalangeal Articulations . . 338
Articulations of the Phalanges . .338
Muscles and Fascia.
General Description of Muscle . . .339
Tendons . . 340
Aponeurosis . . 340
Fascia . . . S40
MtJSCLES AXD FaSCI/E OF THE CrANIUM
AND Face.
Subdivision into Groups .... 341
/ Cranial Region.
Dissection . . . . . .342
Occipito-frontalis . . . . .343
Auricular Region.
Dissection ...... 344
AttoUens Aurem . . . . .344
Attrahens Aurem ..... 344
Reti-ahens Am-em ..... 344
Actions ....... 344
Palpehral Region.
Dissection ...... 345
Orbicularis Palpebrarum . . . 345
Corrugator Supercilii .... 345
Tensor Tarsi : Actions .... 346
Orbital Region.
Dissection . . . . . .346
Levator Palpebras Superioris . . . 346
Rectus Superior ..... 346
Inferior, Internal, and External
Recti 347
Superior Oblicpe . . . . .347
Inferior Oblique ..... 348
Actions : Surgical Anatomy . . . 348
Kasal Region.
PjTamidalis Nasi 349
Levator Labii Superioris Alteque Nasi . 349
Dilatator Naris, Anterior and Posterior . 349
Compressor Nasi . . . . .349
Narium Minor . . .349
Depressor Alse Nasi . . , .349
Action ....... 349
Superior Maxillary Region.
Levator Labii Superioris (Proprius) . 350
Levator Anguli Oris . . . .350
Zygomatici: Actions . . . .350
Inferior Ilaxillary Region.
Dissection .....
Levator Labii Inferioris .
Depressor Labii Inferioris
Depressor Angaili Oris
. 350
. 350
. 351
. 351
Intermaxillary Region.
Dissection .....
Orbicularis Oris ....
Buccinator .....
. 351
. 351
. 352
Risorius ......
Actions ......
. 352
. 352
1 emporo-maxillary Region.
Masseter .....
Dissection .....
Temporal Fascia ....
Temporal .....
. 352
. 353
. 353
. 353
Ptery go-maxillary Region.
Dissection .....
Internal Pterj-gold ....
External Pterygoid
Actions ......
. 354
. 354
, 354
354
Muscles and Fascia or the Neck.
Subdivision into Groups . . . .355
Superficial Cervical Region.
Dissection .....
356
Superficial Cervical Fascia
356
Platysma Myoides ....
356
Deep Cervical Fascia
357
Sterno-mastoid ....
357
Boundaries of the Triangles of the Neck
358
Actions : Surgical Anatomy
359
Lfra-hyoid Region.
Dissection .....
359
Sterno-hyoid ... . .
359
Sterno-thjrold ....
360
ThjTO-hyoId .......
360
Omo-hyold
361
Actions .......
361
Supra-liyoid Region.
Dissection ......
361
Digastric ......
361
CONTENTS.
PAGR
Stylo-hyoid, Mylo-hyoid, Genio-liyoid . 3G2
Actions S62
Lingual Region.
Dissection . . . . . . 363
Genio-hyo-glossus . . . . .363
Hyo-glossus . . . . . .364
Lingual] s, and intrinsic fibres of Tongue . 364
Stylo-glossus, Palato-glossus . . .865
Actions 365
Pliaryngeal Region.
Dissection . . . . . .366
Infei'ior Constrictor . . . .366
Middle Constrictor, Superior Constrictor . 367
Stylo-pliai-yngeus : Actions . . .367
Palatal Region.
Dissection . . . . . .868
Levator Palati 368
Tensor Palati 369
Azygos Uvula;, Palato-glossus, Palato-
pharyngeus . . . . .369
Actions 370
Sui'gical Anatomy . . . . .370
Vertebral Region (^Anterior).
Kectus Capitis Anticus Major and Minor . 370
Kectus Lateralis, Longus Colli . .3 71
Vertebral Region (^Lateral}.
Scalenus Anticus . . . . .372
Scalenus Medius, Scalenus Posticus :
Actions 372
Muscles akd Fasci^k of the Tkunk.
Subdivision Into groups . . . . ;
Muscles of the Bach.
Subdivision Into Layers .
!73
First Layer.
Dissection
Trapezius
LIgamentum Nucliaa
Latlssimus Dorsi
Second Layer
Dissection
Levator Anguli Scapula;
Rhoinboldcus Minor
llhomboideus Major
Actions ....
Hard Layer.
Dissection
S(;iTatus Posticus Superior
Serratus Posticus Ini'crlor
V(!rt<;bral Aponeurosis
Sfjlenius Capitis and Colli
Actions ....
Dissection
Erector Spina;
Fourth L.ayer
373
373
3 74
374
376
376
376
377
377
377
377
378
378
378
378
3 79
379
Sacro-lumbalis
PASE
, 379
Musculus Accessorius a
Sacro-lumbalem
379
Cervicalls Ascendens
. 379
Longisslmus Dorsi .
. 881
Transversalls Colli .
. 881
Trachelo-mastoid
. 881
Spinalis Dorsi
. 381
Spinalis Colli
381
Complexus, Biventer C
ervicis .
. 881
Fifth Layer.
Dissection
.
. 382
Semlsplnalis Dorsi and Colli .
382
Multilidus Spinas
382
Potatores Spina;
. 383
Supraspinales .
. 883
Intersplnalcs .
883
Extensor Coccygis .
383
Intertransversalcs
. 383
Rectus Capitis Posticus
Major .
383
Pectus Capitis Posticus
Minor
384
Obllquus Superior and Inferior
884
Actions .
384
Muscles of
the Abdomen.
Dissection
385
Obllquus Externus .
385
Obllquus Internus .
387
Tansversalls .
388
Lumbar Fascia
389
Pectus .
390
Pyramldalls, Quadratus
Lumborum
391
LInea Alba
391
Lineae Semilunares .
392
Llneas Transversse .
392
Actions .
392
Muscles and Fasci.'e of the Thoeax.
Intercostal Fasciae .
Intercostales Externi
Intercostales Interni
Infracostales, Triangularis Ste:
Levatores Costarum
Actions ....
Diaphragmatic Region.
Diaphragm
Actions .
392
392
393
393
393
394
894
397
Muscles and Fasci.e of the Upper
extkemity.
Subdivision into Groups ....
Dissection of Pectoral Region and Axilla
Fascia; of the Thorax ....
Anterior Thoracic Region.
Pectoralis Major
Costo-coi-acold Membrane
Pectoralis Minor
Subclavius
Actions ....
Lateral I'horacic Region.
Serratus IMagnus ..."
Actions ......
898
398
399
399
401
401
401
402
402
402
CONTENTS.
Acromial Region.
Deltoid .
Actions .
Anterior Scapular Region.
Subscapular Aponeurosis
Subscapulaiis . .
Actions . . . . .
Posterior Scapular Region.
Supraspinous Aponeurosis
Supraspinatus
Intrasplnous Aponeurosis
Infraspinatus .
Teres Minor .
Teres Major .
Actions ....
Anterior Humeral Region.
Deep Fascia of Arm
Coraco-brachialls ....
Biceps ......
Brachialls Antlcus : Actions
Posterior Humeral Region.
Triceps ......
Subanconeus : Actions
Muscles of Forearm.
Deep Tascia of Forearm
PAGB
404
404
404
404
405
405
405
405
405
406
406
407
407
408
408
409
409
410
410
Anterior Brachial Region, Superficial
Layer.
Pronator Kadll Teres
Flexor Carpi Eadlalls
Palmaris Longus
Flexor Carpi Ulnarls
Flexor DIgitorum Subllmis
411
411
412
412
412
Anterior Brachial Region, Deep Layer.
Flexor Profundus Digitorum . . .413
Flexor Longus Pollicis . . . .414
Pronator Quadratus . . . .414
Actions ....... 415
Muscles and Fascice of the Hand.
Dissection .....
Anterior Anniilar Ligament
Posterior Annular Ligament
Palmar Fascia ....
Muscles of the Hand.
Radial Group .....
Ulnar Group .....
Middle Palmar Group . . .
Actions ......
Radial Region.
Dissection ....
Supinator Longus
Extensor Carpi Radlalis Longior
Extensor Carpi Radlalis Brevior
415
415
415
416
PAGF,
420
420
420
421
421
423
424
424
1 Posterior Brachial Region, Superficial
Layer.
Extensor Communis Digitorum . .417
Extensor Minimi Digiti . . , .417
Extensor Carpi Ulnaris . . . .417
Anconeus . . . . . .417
Posterior Brachial Region, Deep Layer.
Supinator Brevis . . . . .418
Extensor Ossis MetacarpI Pollicis . .418
Extensor Primi Internodil Pollicis . .418
Extensor Secundi Internodii Pollicis . 418
Extensor Indicis . . .419
Actions .419
Surgical Anatomy of the Muscles of the
Upper Extremity.
Fractures of the Clavicle
426
Acromion Process
. 426
Coracoid Process
. 426
Humerus
. 426
Ulna .
. 427
Olecranon
. 427
Radius .
. 428
Muscles and Fascite of the Lower
Extremity.
Subdivision Into Groups . . . .429
Iliac Region.
Dissection
Iliac Fascia
Psoas Magnus
Psoas Parvus
Illacus
Actions .
Anterior Femoral Region.
Dissection
Fasclaj of the Thigli : Superficial Fascia .
Deej) Fascia (Fascia
Lata)
Saphenous Open-
ing .
Iliac and Pubic
Portions of Fas-
cia Lata
Tensor Vaglnse Femoris, Sartorlus .
Quadriceps Extensor, Crureus
Rectus Femoris, Vastus Externus
Vastus Internus and Crureus .
Subcrureus : Actions
Internal Femoral Region.
Dissection .....
Gracilis ...<«...
Pectineus .....
Adductor Longus, Brevis, and Magnus
Actions ......
Gluteal Region.
Dissection
Gluteus Maximus
Gluteus Medius
Gluteus Minimus
Pyrlformis
Obturator Membrane
Obturator Internus, Gemelli
430
430
431
431
431
432
432
432
433
434
434
434
435
435
436
436
437
437
437
438
439
439
439
440
441
441
442
442
CONTENTS,
PAQE
Quadratus Femoris, Obturator Externus . 443
Actions 443
Posterior Femoral Region.
Dissection ...... 444
Biceps, Semitenclinosus . . . . 444
Semimembranosus : Actions . . .445
Surgical Anatomy of Hamstring Tendons 445
Muscles and Fascia; of the Leg.
Dissections of Front of Leg . . . 445
Fascia of the Leg ..... 445
Muscles of the Leg . . . .446
Anterior Tibio-Jilular Region.
Tibialis Anticus 446
Extensor Proprius PoUicis . . .447
Extensor Longus Digitorum . . . 447
Peroneus Tertius : Actions . . . 447
Posterior Tibio- fibular Region,
Sujperjicial Layer.
Dissection . . . . . .448
Gastrocnemius ..... 448
Soleus, Tendo Achillis, Plantaris . .449
Actions 449
Posterior Tibio-fibular Region,
Deep Layer.
Deep Fascia of Leg .... 450
Pojiliteus . . . . . . 450
Flexor Longus PoUicis .... 450
Flexor Longus Digitorum, Tibialis Pos-
ticus . . . . . . .451
Actions . . . . . . .452
Fibular Region.
PAGE
Peroneus Longus . . . . .452
Peroneus Brevls ..... 453
Actions ....... 453
Surgical Anatomy of Tendons around the
Ankle 453
Muscles and Fascice of the Foot.
Anterior Annular Ligament . . . 453
Internal Annular Ligament . . . 454
External Annular Ligament . . . 454
Plantar Fascia ..... 454
Muscles of the Foot, Dorsal Region
Extensor Brevis Dio-itorum . . . 455
Plantar Region.
Subdivision into Groups .
. 455
Subdivision into Layers .
. 456
Fu-st Layer
. 456
Second Layer .
. 457
Third Layer
. 458
Interossei
. 459
Surgical Anatomy of the Muscles of the
Lower Extremity.
Fracture of the Neck of the Femur . . 460
the Femur below Trochanter
Minor . . . .460
the Femur above the Condyles 460
the Patella . . . .461
the Tibia . . . .461
the Fibula, with Displacement
of the Tibia . . .461
The Arteries.
General Anatomy.
Subdivision into Pulmonary and
teniic .....
Distribution of — Where Found
Mode of Division — Anastomoses
Arch of the Aorta.
Dissection
Ascending Part of Arch .
Transverse part of Arch .
Descending Part of Arch
Peculiarities, Surgical Anatomy
Branches
Pecvdiarities of Branches
Coronary Arteries
Arteria Innominata.
Relations ....
I'cculiaritics ....
Surgical Anatomy .
Sys-
Common Carotid Arteries.
Course and llelations
Peculiarities .
Surgical Anatomy .
463
463
463
464
465
466
467
468
468
4G9
469
470
470
470
471
473
474
External Carotid Artery.
Course and Relations
Surgical Anatomy .
Branches ....
Superior Tliyroid Artery.
Course and Relations
Branches ....
Sui'gical Anatomy ...
Lingual Artery,
Course and Relations
Branches ....
Surgical Anatomy .
Facial Artery.
Course and Relations
Brandies ....
Peculiarities ....
Surgical Anatomy .
Occipital Artery.
Course and Relations
Branches ....
Posterior Auricular Artery
Ascending I'liuryugeal Artery
475
475
476
476
476
476
477
477
477
478
479
480
480
480
481
481
481
CONTENTS.
Temporal Artery.
Course and Relations
Branclies .....
Surgical Anatomy ....
Internal Maxillary Artery.
Course, Relations
Peculiarities . . ...
Branches from First Portion
Second Portion
Third Portion .
Surgical Anatoviy of tlie Triangles
of the Keck.
Anterior Triangular Space.
Inferior Carotid Triangle
Superior Carotid Triangle
Submaxillary Triangle . . . .
Posterior Triangular Space.
Occipital Triangle . . . . .
Subclavian Triangle . , . .
Internal Carotid Artery.
Cervical Portion
Petrous Portion
Cavernous Portion .
Cerebral Portion
Peculiarities, Surgical Anatomy
Branches ....
Ophthalmic Artery
Cerebral Branches of Internal Carotid
Arteries of the Upper Extremity.
Subclavian Arteries.
First Part of Right Subclavian Artery
First Part of Left Subclavian Artery
Second Part of Subclavian Artery
Third Part of Subclavian Artery
Peculiarities ....
Surgical Anatomy .
Branches ....
Vertebral Artery and its Branches
Basilar Artery and its Branches
Cerebellar Branches of Vertebral
Circle of Willis
Thyroid Axis
Inferior Thyroid
Suprascapular Artery
Transversalis Colli
Internal Mammary
Superior Intercostal
Deep Cervical Artery .
Surgical Anatomy of the Axilla
Axillary Artery.
First Portion ....
Second Portion
Thu'd Portion
Pecuharities, Surgical Anatomy
Branches ....
PAGE
. 482
482
482
483
484
484
485
485
487
487
488
488
488
489
490
491
491
491
491
492
495
496
497
497
497
498
498
600
500
502
502
502
502
502
503
503
504
505
505
505
507
507
508
508
609
Brachial Artery.
Relations
Bend of the Elbow .
Peculiarities of Brachial Artery
Surgical Anatomy .
Branches
Badial Artery.
Relations
Deep Palmar Arch
Peculiarities, Surgical Anatomy
Branches
Ulnar Artery
Relations
Superficial Palmar Ai'ch .
Peculiarities of Ulnar Artery
Surgical Anatomy .
Branches
Descending Aokta .
Thoracic Aorta.
Course and Relations
Surgical Anatomy .
Branches ....
Abdominal Aorta.
Course and Relations
Surgical Anatomy .
Bi'anches
Cceliac Axis
Gastric Artery
Hepatic Artery, Branches
Splenic Artery
Superior Mesentej'ic Artery
Inferior Mesenteric Artery
Suprarenal Arteries
Pi.enal Arteries
Spermatic Arteries .
Phrenic Arteries
Lumbar Arteries
Middle Sacral Arteries
Coccygeal Gland
Common Iliac Arteries.
Course and Relations
Peculiarities .....
Surgical Anatomy ....
Internal Iliac Artery.
Course and Relations
Peculiarities, Surgical Anatomy
Branclies . . . . '
Vesical Arteries
Hemorrhoidal Arteries
Uterine and Vaginal Arteries
Obturator Artery
Internal Pudic Artery
Sciatic Artery
llio-lumbar Artery .
Lateral Sacral Artery
Gluteal Artery
External Iliac Artery.
Course and Relations
Surgical Anatomy . ^
PAGE
511
511
512
513
514
515
515
516
516
518
519
519
520
520
522
622
522
522
525
525
526
526
527
527
529
529
531
532
532
532
533
533
534
534
535
535
636
537
538
538
538
639
639
539
540
542
543
543
643
544
644
CONTENTS.
PAGE
Epigastric Artery ..... 545
Circumtlex Iliac Artery .... 646
Femoral Artery.
Course and Relations . . . .547
Scarpa's Triangle . . . . .547
Surgical Anatomy ..... 548
Peculiarities of the Femoral Artery . 548
Branches . . . . . .550
Profunda Artery and its Branches . . 550
Popliteal Space ..... 552
Popliteal Artery.
Course and Relations .... 553
Peculiarities, Surgical Anatomy . . 553
Branches . . . . . .554
Anterior Tibial Artery.
Course and Relations .... 555
Peculiarities, Surgical Anatomy . . 556
Branches . . . . . .556
Dorsalis Pedis Artery.
Course and Relations
Peculiarities, Surgical Anatomy
Branches ....
Posterior Tibial Artery.
Course and Relations
Peculiarities . . . . ,
Surgical Anatomy . . . ,
Branches . . . . .
Peroneal Artery.
Course and Relations
Peculiai'ities .
Plantar Arteries
Pulmonary Artery
PAGE
557
558
558
559
559
560
560
561
561
561
563
'he Ye ins.
General Anatomy.
Subdivision into Pulmonary, Systemic,
and Portal 564
Anastomoses of Veins .... 564
Superficial Veins, Deep Veins, or Vena3
Comites ...... 564
Sinuses ....... 565
Veins of the Head and Neck.
Facial Vein ...... 665
Temporal Vein . . . . .566
Internal Maxillary Vein . . . .567
Temporo-maxillary Vein . . .667
Posterior Auricvxlar Vein, Occipital Vein 567
Veins of the Neck.
External Jugular Vein . . . .567
Posterior External Jugular Vein . . 568
Anterior Jugular Vein .... 568
Internal Jugular Vein . . . .568
Lingual and Pharyngeal .... 568
Thyroid Veins 668
Vertebral Veins 669
Veins of the Diploe .... 569
Cerebral Veins.
Superficial Cerebral Veins . . . 570
Deep Cerebral Veins . . . .570
Cerebellar Veins . . . . .670
Sinuses of the Dura Mater. .
Superior Longitudinal Sinus . . . 571
Inferior Longitudinal Sinus . . . 671
Straight, Lateral, and Occipital Sinuses . 572
Cavernous Sinuses . . . . .572
Circular Sinuses ..... 672
Inferior Petrosal and Transverse Sinuses . 673
Superior Petrosal Sinus . . . .673
Veins of the Upper Extremity.
Supei-ficial Veins
Deep Veins
Axillaiy Vein
Subclavian Vein
Innominate Veins
Peculiarities of
Internal JMammary Veins
Inferior Thyroid Veins
Superior Intercostal Veins
Superior Vena Cava
AzYGOS Veins .
Bronchial Veins
Spinal Veins .
Veins of the Lower Extremity.
Internal Saphenous Vein
External Saphenous Vein
Popliteal Vein
Femoral Vein
External Iliac Vein
Internal Iliac Vein .
Common Iliac Veins
Inferior Vena Cava
Peculiarities
Lumbar and S])ermatic Veins
Ovarian, Renal; Suprarenal Ve
Phrenic and Hepatic Veins
Portal System of Veins.
Inferior and Superior Mesenteric Veins
Splenic and Gastric Veins
Portal Vein
Cardiac Veins
Coronary Sinus
Pulmonary Veins
573
673
575
576
676
676
576
677
677
677
678
578
578
681
581
582
682
682
582
583
683
583
584
584
584
685
685
585
686
587
587
CONTENTS.
The Lymphatics.
PARE
688
688
689
690
590
690
691
591
591
692
592
692
General Anatomy.
Subdivision into Deep and Superficial
Lymphatic or Conglobate Glands
Thoracic Duct
Right Lymphatic Duct .
Lymphatics of Head, Face, and Neck.
Superficial Ijymphatic Glands of Head
Lymphatics of the Head
of the Face
Deep Lymphatics of the Face .
of the Cranium
Superficial Cervical Glands
Deep Cervical Glands
Superficial and Deeji Cervical Lymphatics
Lymphatics of the Up2:)er Extremity.
Superficial Lymphatic Glands . . .593
Deep Lymphatic Glands . . .593
Axillary Glands 594
Superficial Lymphatics of Upper Extrem-
ity . ._ 594
Deep Lymphatics of Upper Extremity . 594
Lymphatics of the Lower Extremity.
Superficial Inguinal Glands . . .694
Deep Lymphatic Glands . . . .595
Anterior Tibial Gland .... 595
Deep Popliteal Glands . . , .595
Deep Inguinal Glands . . . .595
Gluteal and Ischiatic Glands . . .595
Superficial Lymphatics of Lower Ex-
tremity . . . .595
Internal Group . . . .695
External Group . . . .596
Deep Lymphatics of Lower Extremity . 596
Lymphatics of Pelvis and Abdomen.
Deep Lymphatic Glands of Pelvis . . 596
External Iliac Glands . . .696
Internal Iliac Glands . . . 596
Deep Sacral Glands
Lumbar Glands
Superficial Lymphatics of Wall of Abdo
men ....
of Gluteal Pegion .
of Scrotum and Perineum
of Penis
of Labia, Nj^mphte, and Clitoris
Deep Lymphatics of Pelvis and Abdomen
Lymphatics of Bladder .
of Pectum .
of Uterus
of Testicle .
of Kidney
of Liver
Lymphatic Glands of Stomach
Lymphatics of Stomach .
Lymphatic Glands of Spleen
Lymphatics of Spleen
Lymphatic System of the Intestines.
Lymphatic Glands of Small Intestines
(Mesenteric Glands) . . . .599
Lymphatic Glands of Large Intestine . 599
Lymphatics of Small Intestines (Lacteals) 599
of Large Intestine . .599
PAGE
596
596
696
597
697
697
698
598
698
598
598
598
598
598
599
699
599
699
Lymphatics of Thorax.
Deep Lymphatic Glands of Thorax
Intercostal Glands .
Internal Mammary Glands
Anterior Mediastinal Glands
Posterior Mediastinal Glands
Superficial Lymphatics on front of Thorax
Deep Lymphatics of Thorax :
Intercostal Lymphatics . . . 600
Internal ]Mammary Lymphatics
Lymphatics of Diaphragm
Bronchial Glands
Lymphatics of Lung
Cardiac Lymphatics
Thymic Lymphatics
Thyroid Lymphatics
Lymphatics of ffisophagus
600
600
600
600
600
600
600
600
600
600
600
601
601
601
!N"ervous System.
General Anatomy.
Subdivision into Cerebro-sjiinal Axis,^ Gan-
glia, and Nerves 602
The Spinal Cord and its Membranes.
Dissection •..'..
Membranes of the Cord :
Dura Mater
Arachnoid
Pia Mater
Ligamentum Denticulatum
Spinal Cord ....
Fissures of Cord
Columns of Cord
Structure of the Cord
B
602
602
603
603
604
604
605
605
605
The Brain and its Membranes.
Membranes of the Brain . . . ^06
Dura Mater.
Structure 607
Arteries, Veins, Nerves .... 607
Glandulfe Pacchioni .... 607
Processes of the Dura Mater :
Fabc Cerebri 608
Tentorium Cerebelll . . . 608
Falx Cerebelli 608
Arachnoid Membrane.
Subarachnoid Space . . . .609
Cerebro-spinal Fluid . . . . 609
Pia Mater . . . . ; .609
CONTENTS.
The Brain.
PAGE
Subdivision into Cerebrum, Cerebellum,
Pons Varolii, Medulla Oblongata . . 609
Welo-ht of Brain CIO
Medulla Oblongata.
Anterior Pyramids . , . .
Lateral Tract, and Olivary Body
Eestlform Bodies ....
Posterior Pyramids ....
Posterior Surface of Medulla Oblongata
Structure of Medulla Oblongata
of Anterior Pyramid
of Lateral Tract
of Olivary Body
of Bestlform Body .
Septum of Medulla Oblongata
Gray Matter of MeduUa Oblongata .
Pons Varolii.
Structure .....
Transverse Fibres ....
Longitudinal Fibres
Septum ......
Cerebrum.
Upper Surface of Cerebrum
Convolutions and Sulci
Base of the Brain .
General Arrangement of the Parts
posing the Cerebrum
Interior of tlie Cerebrum
Corpus Callosum
Lateral Ventricle
Corpus Striatum
Tajnia Semlcircularis
Choroid Plexus
Corpus Fimbriatum
Hippocampus .
Transverse Fissure
Septum Lueldum
Fifth Ventricle
Fornix
Foramen of Monro
Velum Interposltum
Thalamus Opticus
Thnd Ventricle
Commissure of Third
Gray Matter of Third
Pineal Gland
Corpora Quadrigemin
Valve of Vieussens
Corpora Genlculata
Structure of Cerebrum
Cerebellum
Its Position, Size, Weight, etc
Cerebellum, Upper Surface
Under Surface .
Lobes of tlie Cerebelkim .
Structui'c of the Cerebellum
Its Lamina}
Corpus Lentatum
Peduncl(!S of Cerebellum .
Fourtii Ventricle
Lining Membrane, Clioroid PI
Gray Matter .
Ventricles
Ventricles
610
611
611
611
612
612
612
612
612
612
613
613
614
G14
614
614
615
615
619
622
622
623
624
625
625
625
626
627
627
627
627
627
628
628
629
629
630
630
630
631
631
631
631
632
632
633
634
634
634
635
635
G35
636
636
Cranial Nerves.
PAGE
Subdivision Into Groups . . . .637
Olfactory Nerve . , . . .637
Optic Nerve 638
Tracts 638
Commissure . . . . .639
Auditory Nerve . . . . .639
Third Nerve . . . . . .640
Fourth Nerve . . . . .641
Sixth Nerve 641
Relations of the Orbital Nerves :
in the Cavernous Sinus . . . 642
in the Sphenoidal Fissure . .642
in the Orbit ..... 642
Facial Nerve . . . . . .642
Branches of Facial Nerve . . 644
Ninth or Hypoglossal Nerve . . .646
Fifth Nerve 647
Casserian Ganglion , . . . 648
Ophthalmic Nerve .... 648
Lachrymal, Frontal, and Nasal
Branches ..... 649
Ophthalmic Ganglion . . .650
Superior Maxillary Nerve . .650
Spheno-palatlne Ganglion . . 652
Inferior Maxillary Nerve . . .654
Auriculo- temporal Nerve . . .655
Gustatory and Inferior Dental
Branches . . . . .656
Otic Ganglion 656
Submaxillary Ganglion . . .657
Eighth Pair 658
Glosso- pharyngeal . . . .658
Spinal Accessory . . . .660
Pueumogastric (Vagus) . . , 660
Origin of Cranial Nerves . . .663
Spinal Nerves.
Eoots of the Spinal Nei'ves . . . 665
Origin of Anterior Roots . . .665
of Posterior Roots . . .665
Ganglia of the Spinal Nerves . . . 666
Antei'ior Branches of the Spinal Nerves . 666
Posterior Branches of the Spinal Nerves . 666
Cervical Nerves.
Roots of the Cervical Nerves . . . 666
Anterior Branches of the Cervical Nerves 669
Cervical Plexus.
Superficial Branches of the Cervical
Plexus 669
Deep Branches of the Cervical Plexus . 669
Posterior Branches of the Cervical Nerves 670
Brachial Plexus.
Branches above the Clavicle.
Posterior Thoracic, Suprascapular .
Branches below the Clavicle.
Anterior Thoracic .
Subscapular Nerves
Circumllex Nerves .
Musculo-cutaneous Nerves
Internal Cutaneous Nerve
J:iesser Jnternnl Cutiineous Nerve
672
6 73
6 73
6 73
674
674
G75
CONTENTS.
PAGE
Median Nerve . . . • .675
Ulnar Nerve . . . . . .6 79
Musculo-spiral Nerve . . . .679
Kadial Nerve 679
Posterior Interosseous Nerve . .679
Dorsal Nerves.
Roots of the Dorsal NerA^es . . .680
Posterior Branches of tlie Dorsal Nerves . 680
Intercostal Nerves . . . . .681
Upper Intercostal Nerves . . .681
Intercosto- humeral Nerves . . .681
Lower Intercostal Nerves . . .681
Peculiar Dorsal Nerves :
First Dorsal Nerve . . . .682
Last Dorsal Nerve . . . .682
Lumbar Nerves.
Root of Lumbar Nerves . . . .682
Posterior Branches of Lumbar Nerves . 682
Anterior Branches of Lumbar Nerves . 682
Lumbar Plexus.
Branches of Lu.mbar Plexus . . .684
Ilio-hypogasti'ic Nerve .... 684
Ilio-inguinal, and Genito-crural Nerves . 684
External Cutaneous, and Obturator
Nerves 686
Accessory Obturator Nerve . . . 686
Anterior Crural Nerve . . . .687
Branches of Anterior Crural . . .687
Middle Cutaneous . . . .687
Internal Cutaneous . . . .687
Long Saphenous . . . .688
Muscular and Articular Branches . 688
Sacral aivd Coccygeal Nerves.
Roots of, Oi-igin of 688
Posterior Sacral Nerves . . . .689
Anterior Sacral Nerves . . . .689
Coccygeal Nerve 689
Sacral Plexus.
Superior Gluteal Nerve . . . .690
Pudic Nerve 690
Sciatic Nerve 692
Great Sciatic Nerve , . . .693
Internal Popliteal Nerve . . .693
Short Saphenous Nerve . . . .693
PA8P,
693
693
694
695
695
Posterior Tibial Nerve
Plantar Nerves ....
External Popliteal or Peroneal Nerve
Anterior Tibial Nerve
Musculo-cutaneous Nerve
Sympathetic Nerve.
Subdivision of, into Parts . . 696
Branches of the Ganglia, General Descrip-
tion of 698
Cervical Portion of the Sympa-
thetic 698
Superior Cervical Ganglion . .698
Carotid and Cavernous Plexuses . .698
Middle Cervical Ganglion . . .699
Inferior Cervical Ganglion . . .699
Cardiac Nerves.
Superior, Middle, and Inferior Cardiac
Nerves . . . . . .700
Deep Cardiac Plexus .... 700
Superficial Cardiac Plexus . . . 700
Anterior and Posterior Coronary Plexus . 701
Thoracic Part of the Sympathetic.
Great Splanchnic Nerve .... 701
Lesser Splanchnic Nerve . . . 702
Smallest Splanchnic Nerve . . . 702
Epigastric or Solar Plexus . . .702
Semilunar Ganglia . . . . .702
Phrenic, Suprarenal, and Renal Plexuses 702
Spermatic, Cceliac, and Gastric Plexuses 703
Hepatic, Splenic, and Superior Mesenteric
Plexuses ...... 703
Aortic, and Inferior Mesenteric Plexuses 703
Lumbar Portion op Sympathetic . 704
Pelvic Portion of Sympathetic . .704
Hypogastric Plexus . . . .704
Inferior Hypogastric or Pelvic Plexus . 704
Inferior Hemorrhoidal Plexus . . . 706
Vesical Plexus 706
Prostatic Plexus 706
Vaginal Plexus . . . . .706
Uterine Nerves ..... 706
Organs of Sense.
Tongue.
Papillffi of . . .
Follicles, and Mucous Glanas
Fibrous Septum of .
Arteries and Nerves of .
Nose.
Cartilages of, IMuscles
Skin, Mucous Membrane
Arteries, Veins, and Nerves
708
709
709
710
711
712
712
Nasal Fossce.
Mucous Membrane of ... .
Peculiarities of, in Superior, Middle,
and Inferior Meatuses .
Arteries, Veins, and Nerves of Nasal
Fossae .......
Eye.
Situation, Foi-m of
Tunics of, Sclerotic
712
712
713
713
714
CONTENTS.
Ciliary Ligament
Cornea .
Choroid .
Ciliary Processes
Iris
Membrana Pupillaris,
Ciliary Muscle
Eetina
Structure of Ketina
Jacob's Membrane
Granular Layer
Nervous Layer
Radiating Fibres of the Retina .
Arteria Centralis RetintB .
Structure of Retina, at Yellow Spot .
Humors of the Eye.
Aqueous Humor ....
Anterior Chamber
Posterior Chamber .
Vitreous Body ....
Crystalline Lens and its Capsule
Changes produced in the Lens by Age
Suspensory Ligament of Lens .
Canal of Petit ....
Vessels of the Globe of the Eye
Nerves of Eyeball ....
Appendages of the Eye.
Eyebrows
Eyelids ....
Structure of the Eyelids
Tarsal Cartilages
Meibomian Glands .
Eyelashes
Conjunctiva
Carunculte Lacrymales
Lachrymal, Apparatus.
Lachrymal Gland ....
Canals ....
Sac ....
Nasal Duct ....
PAGE
715
716
718
718
719
719
720
720
721
721
722
722
722
722
723
723
723
723
724
724
724
725
725
725
725
725
726
726
727
727
727
728
728
729
729
I Ear.
Pinna, or Auricle ....
Structure of Auricle
Ligaments of the Pinna .
Muscles of the Pinna
Arteries, Veins, and Nerves of the Pinna
Auditory Canal ....
Middle Ear, or Tympanum.
Cavity of Tympanum
Eustachian Tube
Membrana Tympani
Structure of
Ossicles of the Tympanum
Ligaments of the Ossicula
Muscles of the Tympanum
Mucous Membrane of Tympanum
Arteries of Tympanum .
Veins and Nerves of Tympanum
Internal Ear, or Lahyrintli.
PAGE
729
729
730
730
731
731
732
734
735
735
735
736
736
737
737
737
Vestibule .....
. 738
Semicircular Canals :
Superior Semicircular Canal
. 739
Posterior Semicircular Canal
. 739
External Semicircular Canal
. 739
Cochlea :
Central Axis of, or Modiolus
. 739
Spiral Canal of ...
. 740
Scala Tympani, Scala Vestibuli, and Sc
ala
Media
. 741
The Organ of Corti
. 741
Perilymph .....
. 743
Membranous Labyrinth .
. 743
Utricle and Saccule
. 743
Membranous Semicircular Canals
. 743
Endolymph: Otoliths
. 744
Vessels of the Labyrinth
. 744
Auditory Nerve, Vestibular Nerve .
. 744
Cochlear Nerve ....
. 744
YISCEEA.
Organs of Digestion and their Appendages.
Subdivisions of the Alimentary Canal
The Mouth ....
The Lips ....
The Cheeks . . • .
The Gums ....
Teeth.
General Characters of . . •
Permanent Teeth ....
Incisors ......
Canine, Bicuspid, Molars
Temporary or Milk Teeth
Structure of the Teeth
Ivory or Dentine, Chemical Composition
Enamel ......
Cortical Substance .
Development of the Teeth
of the Permanent 'J'eeth
Eruption of the 1'eeth
745
745
745
746
746
74 7
747
747
748
749
749
750
751
751
751
755
Palate.
Hard Palate . . . . .
Soft Palate
Uvula, Pillars of the Soft Palate .
Mucous Membrane, Aponeurosis,
Muscles of Soft Palate
and
Tonsils.
Arteries, Veins, and Nerves of Tonsils
Salivary Glands.
Parotid Gland.
Steno's ])uct .....
Vessels and Nerves of Parotid Gland
756
756
756
756
757
758
758
CONTENTS.
Suhmaxillary Gland.
Wliarton's Duct ....
Vessels and Nerves of Submaxillary Gland 759
SuMingual Gland.
Vessels and Ner-\'es of . . .
Structure of Salivary Glands .
Pharynx and GEsophagus.
Sti-ucture of Pharynx
Relations of (Esophagus .
Surgical Anatomy and Structure of (Eso-
phagus .....
Boundaries
Apertures of
Regions .
Abdomen.
Peritoneum.
Reflections traced .
Foramen of Winslow
Lesser Omentum
Great Omentum
Gastro- splenic Omentum
Mesentery
Mesocascum
Mesocolon
Mesorectum, Appendices Epiploicas
Stomacli.
Situation
Splenic end, Pyloric end .
Cardiac and Pyloric Orifices
Greater and Lesser Curvatures
Surfaces ....
Ligaments of .
Alterations in Position
Pylorus ....
Structure of Stomach
Serous and Muscular Coats
Mucous IMembrane .
Gastric Follicles
Vessels and Nerves of Stomach
Small Intestines.
Duodenum .....
Ascending portion
Descending portion .
Transverse portion .
Vessels and Nerves of Duodenum .
Jejunum .....
Ileum ......
Structure of Small Intestines .
Serous, Muscular, and Cellular Coats
INIucous Membrane ....
Epithelium and Valvulaj Conniventes
Villi — tlieir Structure
Simple Follicles, Duodenal Glands .
Solitary Glands ....
Aggregate, or Peyer's, Glands .
Large Intestine.
Caecum ......
Appendix Cajci Vermiformis
Ileo-cffical Valve
PAGE
Colon
PAGE
. 779
. 758
Ascending
. 779
i 759
Transverse
779
Descending
779
Sigmoid Flexure
. 779
. 759
759
Rectum .
. 780
Upper portion .
. 780
Middle portion
. 781
Lower portion .
. 781
Structure of Large Intestine .
. 781
. 759
. 760
Serous and Muscular Coats
. 781
Cellular and Mucous Coats
• 782
Epithelium, Simple Follicles .
. 782
. 761
Solitary Glands
Liver.
. 782
. 762
. 762
. 762
Size, Weight, Position of
. 783
Its Surfaces and Borders .
. 783
Changes of Position
. 783
Ligaments.
. 763
Longitudinal, Lateral
. 783
. 765
. 766
Coronary ....
. 784
Round Ligament
. 784
. 766
. 766
Fissures.
. 766
Ijongitudinal ....
. 784
. 766
Fissure of Ductus Venosus
. '784
. 766
Portal Fissure
. 785
. 767
Fissures for Gall Bladder and
Vena
Cava
. 785
. 767
Lobes.
. 767
Right . .
. 785
. 767
Left
• 785
. 767
Quadratus, Spigelii, Caudatus
. 786
. 767
Vessels and Nerves of Liver .
786
. 76 7
Structure of Liver .
. 786
. 768
Serous Coat, Fibrous Coat
. 786
. 768
Lobules .....
. 786
. 769
Hepatic Cells
. 787
. 769
Biliary Ducts . . . .
. 788
. 769
Portal Vein ....
. 789
. 7 70
. 770
Hepatic Artery, Hepatic Veins
Gall Bladder.
. 789
Structure . . . . .
. 790
. 771
Biliary Ducts .
. 790
. 771
Flepatic Duct .
. 790
. 771
Cystic Duct
. 790
. 771
Common Choledoch Duct
. 791
. 771
Structure of Biliary Ducts
. 791
. 772
. 772
Pancreas.
. 773
. 773
Dissection ....
. 791
. 778
Relations ....
. 792
773
Duct
. 793
. 773
Structure, Vessels, and Nerves
. 793
. 775
. 775
Spleen.
. 776
Relations
. 793
Size and Weight . . . .
. 794
Structure of Serous and Fibrous Coa
ts . 794
. 777
Proper Substance . . . .
. 795
. 778
Malpighian Corpuscles
. 796
. 778
Splenic Artery, distribution
. 797
CONTENTS.
Capillaries and Veins of Spleen
Lymphatics and. Nerves . . . ,
PAQE
797
798
THOEAX.
Boimdaries of .
799
Superior Ojiening, Base ....
Parts passing through Upper Opening
799
799
Pericardium.
Structure ......
Fibrous Layer, Serous Layer .
800
800
Heart.
Position, Size .....
Subdivision into Four Cavities
Circulation of Blood in Adult .
Auriculo-ventricular, and Ventricular
Grooves . . . . .' .
801
801
801
802
Right Auricle.
Openings ......
Valves .......
Relics of Foetal Structures
Musculi Pectinati
803
803
804
804
Right Ventricle.
Openings ......
Tricuspid Valve .....
804
805
Semilunar Valve ..... 805
Chordae Tendineaj and Columnaj Carncre 805
Reft Auricle,
Sinus and Appendix
Openings
Musculi Pectinati
Reft Ventricle.
Openings . . . .
Mitral and Semilunar Valves .
Endocardium
Structure of Heart.
Fibrous Kings ....
Muscular Structure ....
of Auricles
of Ventricles .
Vessels and Nerves of Heart .
Peculiarities in Vascular System
Foetus .....
Foramen Ovale, Eustachian Valve .
Ductus Arteriosus ....
Umbilical or Hypogastric Arteries .
Foetal Circulation ....
Changes in Vascular System at Bu-th
of
806
806
807
807
807
808
808
808
808
809
810
810
810
810
811
812
813
Organs of Yoice and Respiration.
The Rarynx.
Cartilages of the Larynx
Thyroid Cartilage ...
Cricoid .....
Arytenoid Cartilages
Cartilages of Santorini, and of Wris
berg .....
Epiglottis ....
Ligaments of the Larynx
Ligaments connecting the Thyroid Car
tilage with the Os Hyoides .
Ligaments connecting the Thyroid Car
tilage with the Cricoid
Ligaments connecting the Arytenoid Car
tilages to the Cricoid .
Ligaments of the Epiglottis
Superior Aperture of the Larynx
Cavity of the Larynx
Glottis
False Vocal Cords ....
True Vocal Cords ....
Ventricle of Larynx, Sacculus Laryngis
Muscles of Larynx ....
Crico-thyrold ....
Crico-aryta;noidcus posticus
lateralis
Thyro-arytaenoidcus
Arytajnoideus ....
Muscles of the Epiglottis .
Thyro-cpiglottidcus
Arytaano-epiglottideus, superior
inferior
Actions of Muscles of Larynx .
Mucous M(!mbrane of Larynx .
Glands, Vessels, and Nerves of Larynx
814
814
815
815
816
816
816
816
817
817
817
817
818
818
818
819
819
819
819
819
820
820
820
820
821
821
821
821
821
822
Trachea.
Relations . . . . . .823
Bronchi 823
Structure of Trachea .... 824
Surgical Anatomy of Laryngo-tracheal
Region 824
The Pleura.
Reflections 826
Vessels and Nerves . . . .827
ISIediastinum.
Anterior Mediastinum . . . .827
Middle Mediastinum . . . .827
Posterior Mediastinum . . . .827
The Rungs.
Siu'faces 828
Borders 829
Lobes 830
Root of Lung 831
Weight, Color, and Properties of Sub-
stance of Lung . . . . .831
Structure of Lung . . . . .831
Serous Coat, and Subserous Areohir
Tissue ...... 831
Parenchyma and Lobules of Lung . . 831
BroiKthi, AiTangemcnt of, in Substance
of Lung 831
Structure of Smaller Bronchial Tubes . 833
Tlie Air-cells 833
Pulmonary Artery 833
I'ulmouary C!iipillaries and Veins . . 833
Broncliial Arteries and Veins . . . 834
Jjymphatics and Nerves of Lung . . 834
CONTENTS.
Thyroid Gland.
Structure
Vessels and Nerves
Cliemical Composition
PAGE
834
835
836
Tliymus Gland.
Structure
Vessels and Nerves
Chemical Composition
PAGE
836
837
837
The Urinary Organs.
Kidneys.
Relations
Dimensions, Weight
General Structure .
Cortical Substance .
Medullary Substance
Minute Structm^e
Malpigliian Bodies .
Malpighian Tufts
Capsule
Tubuli Uriniferi, Course
Structure
Renal Bloodvessels .
Benal Veins .
Venae Eectse .
Lymphatics and Nerves .
Ureters.
Situation
Calices ....
Course, Relations, Structure
838
839
840
840
841
841
841
841
842
843
843
845
845
845
846
846
Suprarenal Capsules.
Relations ....
Structure ....
Vessels and Nerves
Boundaries
Contents
The Pelvis.
Bladder.
Shape, Position, Relations
Urachus .
Subdivisions
Ligaments
Structure
Interior of Bladder
Vessels and Nerves
Male Urethra
Divisions
Structure
847
847
848
848
849
849
850
850
850
851
851
852
853
854
Male Generative Organs.
Prostate Gland ....
855
Structure ....
855
Vessels and Nerves .
856
Prostatic Secretion
856
Cowper's Glands . . . .
856
Penis.
Root ......
.- 856
Glans Penis .....
856
Body
856
Corpora Cavernosa
. 857
Corpus Spongiosum
. 857
The Bulb . . ._ .
. 858
Structure of Corpus Spongiosum
. 858
Erectile Tissue ....
858
Arteries of the Penis
858
Lymphatics of the Penis
859
Nerves of the Penis
859
The T'estes and their Coverings.
Scrotum 859
Other Coverings of the Testis . . . 860
Vessels and Nerves of the Coverings of
the Testis 860
Spermatic Cord.
Its Composition . . . . .860
Relations of, in Ingiilnal Canal . . 860
Arteries of the Cord
Veins of the Cord . . . .
Lymphatics and Nerves of the Cord
Testes.
Form and Situation
Size and Weight
Coverings
Tunica Vaginalis
Tunica Albuginea
Mediastintim Testis .
Tunica Vasculosa
Structure of the Testis
Lobules of the Testis
Tubuli Seminlferi .
Arrangement In Lobuli .
in Mediastinum Testl;
in Epididymis
Vasculum Aberrans
Vas Deferens, Course, Relations
Structure
Vesicula3 Semlnales
Form and Size
Relations
Structure
Ejaculatory Ducts .
The Semen
Descent of the Testes
Gubernaculum Testis
Canal of Nuck
860
861
861
861
861
861
861
862
862
862
862
862
863
863
863
863
863
863
864
864
864
864
864
865
865
865
865
866
CONTENTS.
Female Organs of Generation.
Mons Veneris, Labia Majora .
Labia Minoi-a, Clitoris, Meatus Uriuarlus,
Hymen, Glands of Bartlioline
Female Bladder . . . .
Female Urethra . . . .
Female Mectum . . . .
Relations
Structure
Vagina.
Uterus.
Situation, Form, Dimensions
Fundus, Body, and Cervix
Ligaments
Cavity of tlie Uterus
Structure
Vessels and l^erves
Its Form, Size, and Situation
in the Foetus
at Puberty
during and after Menstruation
PAGE
867
868
869
869
870
871
871
871
871
872
872
873
873
873
873
Its Form during Pregnancy
after Parturition
in Old Age
Ap2:)endages of the Uterus.
Fallopian Tubes
Structure
Ovaries
Structure
Graafian Vesicles
Discharge of the Ovum
Corpus Luteum
Ligament of the Ovary
Round Ligaments .
Vessels and Nerves of Appendaj;
Mammary Glands.
Situation and Size .
Nipple .....
Structure of Mamma
Vessels and Nerves
PAGE
873
873
873
873
874
874
874
874
875
875
876
87G
876
876
877
877
877
Surgical Anatomy of Inguinal Hernia.
Coverings of Inguinal Hernia.
Dissection ....
Superficial Fascia
Superficial Vessels and Nerves
Deep Layer of Superficial Fascia
Aponeurosis of External Oblique
External Abdominal Ring
Pillars of the Ring
lutercoluninar Fibres
Fascia
Poupart's Ligament
Gimbernat's Ligament
Triangular Ligament
Internal Oblique Muscle
Cremaster
Transversalis Muscle
Spermatic Canal
Fascia Transversalis
Internal Abdominal Ring
Subserous Areolar Tissue
878
878
878
879
879
880
880
880
880
880
881
881
881
881
882
882
882
883
883
Epigastric Artery ....
Peritoneum .....
Inguinal Hernia.
Oblique Inguinal Hernia
Course and Coverings of Oblique Hernia
Seat of Stricture
Scrotal Hernia
Bubonocele
Congenital Hernia .
Infantile Hernia
Direct Inguinal Hernia.
Course and Coverings of the Hernia
Seat of Stricture . . . . .
Incomplete Direct Hernia
Comparative Frequency of Oblique and
Direct Hernia .....
Diagnosis of Oblique and Direct Hernia .
883
884
884
884
885
885
885
885
885
886
886
886
886
Surgical Anatomy of Femoral Hernia
Dissection
886
Crural Arch .....
890
Superficial Fascia .
886
Gimbernat's Ligament
891
Cutaneous Vessels .
886
Crural Sheath ....
891
Internal Saphenous Vein
886
Deep Crural Arch ....
891
Superficial Inguinal Glands
887
Crural Canal .....
891
Cutuneons Nerves .
887
Femoral or Cnn-al Ring .
892
Deep Layer of Superficial Fasc
ia
888
Position of Parts around the Ring .
892
Criljriform Fascia .
888
Septum Cnn-iile ....
893
Fascia I^ata .
889
Descent of Femoral Hernia
893
Iliac Portion •.
889
Coverings of Femoral Hernia .
894
Pubic Portion .
889
A^arietles of ]'\'moral Hernia .
894
Saphenous Oldening
889
Scat of Stricture ....
894
CONTENTS.
Surgical Anatomy of Perineum and Ischio-
rectal Region.
Iscliio-rectal Region.
Dissection of . . . .
Boundaries of .
Superficial Fascia . ■ .
External Sphincter
Internal Sphincter . .
Ischio-rectal Fossa .
Position of Parts contained in
Perineum.
Boundaries and Extent .
Supei-ficial Layer of Superficial Fascia
Deep Layer of Superficial Fascia
Com-se taken by the Urine in Rupture of
the Urethra ....
Muscles of the Perineum (Male)
Accelerator Urinas .
Erector Penis ....
Transversus Perinsei
Muscles of the Perineum (Female) :
Sphincter Vaginaj
Erector Clitoridis
895
895
895
896
89G
896
896
897
897
897
897
898
899
899
900
900
Transversus Perinsei
Deep Perinseal Fascia
Anterior Layer
Posterior Layer
Parts between the Two Laj-ers
Compressor Ure three
Cowjjer's Glands
Pudic Vessels and Nerves
Artery of the Bulb .
Levator Ani ....
Relations, Actions .
Coccygeus, Relations, Actions
Position of Viscera at Outlet of Pelv
Prostate Gland ....
Parts concerned in the Operation of Litho-
tomy ......
Parts divided in the Operation
Parts to be avoided in the Operation
Abnormal Course of Arteries in the Peri-
neum ......
Pelvic Fascia . . . . ' .
Obturator Fascia
Recto-vesical Fascia
PAGE
900
900
901
901
901
901
901
901
901
901
902
902
902
902
903
904
904
905
905
906
906
LANDMARKS, MEDICAL AND SURGICAL.
The Head.
Scalp ; its density — Arteries of Scalp —
Skullcap — Frontal Sinuses — ^Mastoid pro-
cess— Occipital Protuberance- — Lines of
Cerebral Sinuses — Middle Meningeal Ar-
tery— Thickness of Skullcap — Levels of
the Brain 914-915
The Face.
Foramina for Branches of 5th Nerve —
Pulley for Superior Oblique Muscle — ■
Lower Jaw — Parotid Duct — Temporal
and Facial Arteries — Eyelids and Eyes- — -
Puncta Lacrymalia — Lachrymal Sac — -
Nasal Duct — Nose and Nasal Cavities — -
Mouth — Throat — Antrum — Posterior
Nares — Tonsils — Features . . 915-919
The Neck.
Subcutaneous Veins — Parts in Central
Line — Os-hyoides — Thyroid Cartilage —
Cricoid Cartilage — -Trachea — Stern o-mas-
toid Muscle— Stern o-clavicular Joint —
Apex of Lung in the Neck — Supra-cla-
vicular Fossa — Subclavian Ai'tery . 920-922
The Chest.
Peculiarities in the Female — Parts be-
hind first Bone of Sternum — Rules for
Counting the Ribs — Interval below Cla-
vicle— Internal Mammary Artery — Out-
line of Heart on Chest- wall — Apex of the
Heart — Valves of the Heart — Outline of
the Lungs — Anterior Mediastinum — Re-
flection o"f Pleura .... 922-925
The Back.
Median Furrow — Spines of Vertebrae —
Division of the Trachea ■ — ■ Origins of
the Spinal Nerves — Movements of the
Spine — Position and Motions of Scapula
926-928
The Abdomen.
Abdominal Lines — Umbilicus — Parts
behind Linea Alba — Peritoneum — Di-
A'ision of Aorta — Bony Prominences —
Spine of Ilium — Spines of Pubes — Pou-
part's Ligament, or Crural Arch — Abdo-
minal Rings — Inguinal Canal — Spermatic
Cord — Epigastric Artery — Abdominal
Viscera — Liver — Gall Bladder — Stomach
— Pylorus — Spleen — Pancreas — Kidney
Large Intestine — Colotomy — Small In-
testines—Bladder . . . 928-934
The Perineum.
Bony Framework — Raphe — Central
Point of Perineum — Triangular Ligament
— Anus — Landmarks in the Rectum —
Urethra — Prostate Gland — Introduction
of Catheters— Urethra in the Child 934-936
The Thigh.
Poupart's Ligament, or Crural Arch —
Furrow at the Bend of the Thigh — Saphe-
nous Opening — Femoral Ring — Lympha-
tic Glands in the Groin — Trochanter
Major — Nelaton's Line — Spine of the
Ilium — Compression of Femoral Artery —
Sartorius — Line of F emoral Artery 936-938
CONTENTS.
The Buttocks.
Bony Landmarks — Fold of the But-
tock— Gluteal Aiteiy— Pudic Artery 938-93 9
The Knee.
Bony Points — Ligamentum Patellae —
Patellar Bursa — Synovial Membrane of
Knee — Popliteal Tendons — Popliteal
Bursa — Popliteal Artery — Peroneal
Nerve 939-941
The Leg and Ankle.
Bony Points — Malleoli — Tendo AchlUis
— Tendons behind Inner Ankle — Ten-
dons behind Outer Ankle — Tendons in
front of Ankle — Popliteal Artery — Ante-
rior Tibial Artery- — ^ Posterior Tibial
Ai-tery — Saphena Veins . . 941-943
The Foot.
Points of Bone — Lines of Joints —
Dorsal Artery — Bursa — Plantar Arteries
— Plantar Fascia .... 943-944
The Arm.
Clavicle — Bony Points of the Shoulder
— Tuberosities — Coraco-acromial Liga-
ment — Axilla — Axillary Artery — Bra-
chial Artery^ — Bend of Elbow — Cutaneous
Veins — Landmarks of Elbow — Olecranon
—Relations of Olecranon and Condyles —
Bursa; — Interosseous Arteries — Lympha-
tic Gland 94-i-:347
The Forearm and Wrist.
Ulna — Radius — Carpus — Pulse — Great
Carpal Bursa — ' ' Tabati^re Anatomique' '
— Tendons on back of Wrist — Lines of
Arteries 947-948
The Hand.
Furrow in Palm — Interdigital Folds —
Digital Furrows — Palmar Arterial Arches
— Digital Arteries — Metacarpal Joint of
Thumb — Sesamoid Bones — Subcutaneous
Veins — Interosseous Arteries — Digital
Bursa3 — Knuckles and Digital Joints 949-950
Palpation by the Rectum .
Examination Per Vaginam
950
951
INDEX 953
LIST OF ILLUSTRATIONS.
'The illustrations, when copied from any other work, have the author's name affixed,
such acknowledgment is made, the drawing is to be considered original.
When no
Introduction.
FIGt,
[1. Corpuscles of Frog's Blood
2. Human Blood Globules
3. White Corpuscles
4. Changes of Colorless Corpuscle .
5. Blood Crystals .
6 . Chyle from the Lacteals
[7. Ai-eolar Tissue . c .
8. White Fibrous Tissue
9. Yellow Elastic Tissue
10. Formative Cells of Yellow Elastic Tissue
11. FormatiA^e Cells of Ai-eolar Tissue
[12. Bloodvessels of Fat
13. Adipose Tissue .
14. Human Cartilage Cells .
15. Costal Cartilage in Old Age
16. Fibro- cartilage .
17. Yellow Cartilage
18. Transverse Section of Bone
19. Longitudinal Section of Bone •
20. Section of Bone after Removal of Earthy Portion
21. Ossification of Foetal Cartilage .
22. Ossification of Foetal Cartilage .
23. Transverse Section of Foetal Femur
24. Intramembranous ossification
25. Transverse Section of Muscle .
26. Human Muscular Fibres
27. Elementary Structure of Voluntary Muscle
28. Elementary Structure of Voluntary Muscle
29. Muscular Fibres of the Heart
30. Non-striated Muscular Fibres
31. Muscular Fibre-cells
32. Nerve Vesicles from Casserian Ganglion
33. Nerve Vesicles from Brain
34. Human Nerve Tubes
35. Nerve Tubes of Eel
36. Nervous Branch from Sympathetic
37. Transverse Section of Spinal Cord
38. Transverse Section of Spinal Cord
39. Longitudinal Section of Spinal Cord
40. Tactile Corpuscles of Wagner
41. Pacinian Corpuscle
42. Termination of Nerves of Voluntary Muscle, "Motorial End
Plates"
43. Terminations of Nerves of Voluntary Muscle
44. Section of Small Artery and Vein
45. Capillary Vessels
46. Capillary Vessels
47. Section of Small Artery and Vein
48. Section of Thoracic Duct
49. Stomata of Serous Membranes .
60. Section of Lymphatic Gland
51. Follicle from Lymphatic Gland
FKOM
Wagner']
PAGK
34
Kolliker
34
Harley
35
Kirkes
35
Harley
36
do.
87
Todd Sf Boioman']
39
Harley
40
do.
40
Kolliher
40
do.
40
Todd Sf Bowman']
42
Harley
42
Kolliker
43
Harley
44
do.
45
do.
46
Kolliker
48
do.
48
Harley
50
Rollett
52
Frey
53
do.
53
do.
54
Kolliker
56
do.
57
Todd and Bowman
57
Quain
68
Scliweigger-Seidel
58
Harley
59
Kolliker
69
Todd and Bowman
61
Harley
61
Kolliker
62
Todd and Bowman
62
Frey
63
J. L. Clarke
66
do.
67
do.
67
Kolliker
72
Todd and Bowman
72
Kuline
74
Beale
75
Kolliker
76
Frey
79
Kolliker
80
Kolliker
80
do.
81
Frey
82
do.
82
do.
83
( xxvii )
LIST OF ILLUSTEATIONS.
FIG.
62.
63.
[54.
[55.
56.
[57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
]\Iedullary Structure of Lymphatic Gland
Sectional View of the Skin and its Appendages
Structure of Hair, etc. .
Sudoriferous Glands
Pavement Epithelium
Tesselated Epithelium .
Columnar Ejaithelium
Spheroidal Epithelium .
Ciliated Epithelium
Ovum of Sow
Human Ovum
DiagTam of the Division of the Yolk
Diagram of the Division of the Blastodermic Membrane
Section of Blastoderm .
Diagrams of the Development of the Three Layers
Blastodermic Membrane — Transverse Sections
Similar Diagrams — Antero-posterlor Sections
Transverse Section through Embryo-chick
Diagrammatic Section through 0\T.im .
Human Embryo of 4 Weeks
Diagram of the Membranes of the Ovimi
Human Ovum, 12 to 14 days
Human Ovum, 15 days
Embryo from the preceding Ovum
Human Ovum In the 4th Week
Transverse Section through Embryo-chick
Primitive Vertebral Column of Embryo
Face of an Embryo of 25 to 28 days
Longitudinal Section of Head of Embryo at 4 Weeks
Vertical Section of Elead in Early Embryos of Habbit
Section of the Medulla of Embryo at 6 Weeks .
Diagram of Development of Lens
Diagrammatic Section through Foetal Eyeball .
Development of Bloodvessels
Heart of Embryo, 6th Week
Diagram of Formation of the Aortic Arches and Larger
Diagram of Formation of the Main Systemic Veins
Early Form of Alimentary Canal
Wolffian Body In the Asexual Stage of Embryo
Diagram of Primitive Urogenital Organs
Adult Ovary, Parovarium, and Fallopian Tube
Female Genital Organs of Embryo
Development of External Genital Organs
of the
Arteri
. FROM
Frey
Kblliker
do.']
do.]
Harley
Klein^
Kolliker
Harley
Kolliker
M. Barry
Kblliker
do.
Bischoff
Foster and Balfour
Beaunis Sc BoucJiard
do.
Foster and Balfour
Qua in
do.
Wagner
A. Thompson
do.
do.
do.
Foster and Balfour
Kblliker
Caste
Kblliker
Mlhalkovics
Kblliker
liemak
Quain
Klein
Baer
•Kblliker
do.
do.
Farre
Quain
Farre
After J. Miiller
Ecker
Osteology,
94. Cervical Vertebra
95. Atlas ....
96. Axis ....
97. Seventh Cervical Vertebra
98. Dorsal Vertebra
99. Peculiar Dorsal Vertebra3
100.- Lumbar Vertebra
101 to 106. Development of a Vertebra
107. Sacrum, anterior surface
108. Vertical Section of the Sacrum .
109. Sacrum, posterior surface
110 to 112. Development of Sacrum
113. Coccyx, anterior and posterior sui'faccs
114. Lateral View of Spine .
115. Occipital Bone, outer surface
116. Occipital lionc, inner surface
117. Occipital Bone, development of
118. Parietal Bone, external surface
119. Parietal Bone, internal surface .
120. Frontal Bone, outer surl'ace
121. Frontal Bone, inner surface
122. Frontal ]5()ne at Birth .
123. Temporal Bone, outer surface .
Quain
Quain
Quain
LIST OF ILLUSTRATIONS.
FIG. . FROM PAGE
124. Temporal Bone, Inner surface ........ 162
125. Temporal Bone, petrous portion . . . . . . .163
126. Temporal Bone, development of . . . . . Quain 164
127. Sphenoid Bone, superior surface ... . . . . . 165
128. Sphenoid Bone, anterior surface . . . . . . .166
129. Sphenoid Bone, posterior surface ....... 168
130. Plan of the Development of Sphenoid ....... 169
131. Ethmoid Bone, outer surface . . . . . . . .170
132. Perpendicular Plate of Ethmoid, enlarged . . . . . .170
133. Ethmoid Bone, inner surface of right lateral mass, enlarged . . . .171
134. Skull at Birth, showing the anterior and posterior Fontanelles . . .173
135. Lateral- Fontanelles . . . . . . . . . 173
136. Nasal Bone, outer surface ........ 174
137. Nasal Bone, inner surface . . . . . . . . 174
138. Superior Maxillary Bone, outer surface . . . . . .175
139. Superior Maxillary Bone, inner surface . . . . . .176
140. Development of Superior Maxillary Bone .... Quain 179
141. Lachrymal Bone, outer surface . . . . . . . .180
142. Malar Bone, outer surface ........ 180
143. Malar Bone, inner surface ........ 181
144. Palate Bone, internal view, enlarged . . . . . . .182
145. Palate Bone, jDOsteri or view, enlarged . . . . . . .183
146. Inferior Turbinated Bone, inner surface ...... 184
147. Inferior Turbinated Bone, outer surface ...... 184
148. Vomer . . . . . . . . . . . 185
149. Lower Jaw, outer surface ........ 186
150. Lower Jaw, inner surface . . . . . . . .187
151. SIfle- view of the Lower Jaw, at Birth ....... 189
152. Side-view of the Lower Jaw, at Puberty ....... 189
153. Side-view of the Lower Jaw, in the Adult ...... 189
154. Side-view of the Lower Jaw, in Old Age ... . . •. '. 189
155. Base of Skull, inner surface ........ 193
156. Base of Skull, outer surface . . . . . . . .196
157. Side-view of Skull . . . . . . . . .199
158. Anterior region of Skull ........ 201
159. Nasal Fossa3, outer wall . . . . . . . . 204
160. Nasal Fossa;, inner wall or septum ....... 205
161. Hyoid Bone, anterior surface ........ 206
162. Sternum and Costal Cartilages, anterior surface ..... 208
163. Sternum, posterior surface ........ 208
164 to 167. Development of Sternum ..... Quain 210
168. A Rib ........... 211
169. Vertebral Extremity of a Eib . . . . . . . .212
170 to 174. Peculiar Ribs ......... 213
175. Left Clavicle, anterior surface . . . . . . . .217
176. Left Clavicle, inferior surface . . . . . . . .217
177. Left Scapula, anterior surface, or venter . . . . . .219
178. Left Scapula, posterior surface, or dorsum ...... 220
179. Plan of the Development of the Scapula ...... 223
180. Left Humerus, anterior view ........ 224
181. Left Humerus, posterior surface . . . . . . .227
182. Plan of the Develojjment of the Humerus ...... 228
183. Bones of the Left Forearm, anterior surface ...... 229
184. Bones of the Left Forearm, posterior surface . . . . . .232
185. Plan of the Development of the Ulna . . . . . . , 233
186. Plan of the Development of the Radius ...... 235
187. Bones of the Left Hand, dorsal surface . . . . . .237
188. Bones of the Left Hand, palmar surface ...... 239
189. Plan of the Development of the Hand ....... 244
190. Os Innominatum, external surface ....... 245
191. Os Innominatum, internal surface ....... 246
192. Plan of the Development of the Os Innominatum ..... 250
193. Male Pelvis (adult) ......... 252
194. Female Pelvis (adult) . . . . ' . . . . .252
195. Vertical Section of the Pelvis, with lines indicating the Axes of the Pelvis . . 253
196. Right Femur, anterior surface ........ 255
197. Right Femur, posterior surface . . . . . . . .257
198. Diagram showing the Structure of the Neck of the Femur . . Ward 259
199. Plan of the Development of the Femur ...... 260
200. Right Patella, anterior surface ........ 260
LIST OF ILLUSTRATIONS.
201. Right Patella, posterior surface
202. Tibia and Fibula, anterior surface
203. Tibia and Fibula, posterior surface
204. Plan of the Develoj^ment of the Tibia .
205. Plan of the Development of the Fibula
206. Bones of the Eight Foot, dorsal sui^face
207. Bones of the Right Foot, plantar surface
208. Plan of the Develojoment of the Foot .
FROM PAGE
260
261
Articulations.
209.
210.
211.
212.
213.
214.
215.
216.
217,
218.
219.
220.
221.
222.
223.
224.
225.
226.
227.
228.
229.
230.
231.
232,
234.
235.
236.
237.
238.
239.
240.
241.
Arnold
Arnold
Vertical Section of Two Vertebrse and their ligaments, front view
Occipito-atloid and Atlo-axoid Ligaments, front view .
Occipito-atloid and Atlo-axoid Ligaments, posterior view
Articulation between Odontoid Process and Atlas .«
Occipito-axoid and Atlo-axoid Ligaments
Temporo-maxillary Articulation, external view
Temporo-maxillary Ai'ticulation, internal view .
Temporo-maxillary Articulation, vertical section
Costo- vertebral and Costo-transverse Articulations, anterior view
Costo- transverse Articulation .....
Costo-sternal, Costo-xiphoid, and Intercostal Articulations, anterior view
Articulations of Pelvis and Hip, anterior view .....
Articulations of Pelvis and Hip, posterior view . . . • .
Vertical Section of the Symphysis Pubis .....
Sterno-clavicular Articulation .......
Shoulder-joint, Scapulo-clavicular Articulations, and proper Ligaments of Scapula
Left Elbow-Joint, showing anterior and internal Ligaments
Left Elbow-Joint, showing posterior and external Ligaments . . . .
Ligaments of Wrist and Hand, anterior view .... Arnold
Ligaments of Wrist and Hand, posterior view .... do.
Vertical Section of Wrist, showing the Synovial Membranes ....
Articulations of the Phalanges ........
Left Hip-Joint, laid open ........
233. Hip-Joint laid ojjen from the Pelvis to show the Ligamentum Teres put on the
stretch by rotation of the Femur outwards, and by adduction in the flexed position
respectively .......
Right Knee- Joint, anterior view
Right Knee-joint, posterior view ....
Right Knee-Joint, showing internal Ligaments
Head of Tibia, with semilunar Cartilages, seen from above
Ankle-Joint, Tarsal and Tarso-metatarsal Articulations, internal view
Ankle-joint, Tarsal and Tarso-metatarsal Articulations, external view
Ligaments of Plantar Surface of the Foot
Synovial Membranes of the Tarsus and Metatarsus
Arnold
Muscles and Fasciae.
242. Plan of Dissection of the Head, Face, and Neck
243. Muscles of the Head, Face, and Neck .
244. Muscles of the Right Orbit ....
245. The relative position and attachment of the Muscles of the Left Eyeball
246. The Temporal Muscle .....
247. The Pterygoid Muscles .....
248. Muscles of the Neck, and Boundaries of the Triangles .
249. Muscles of tlie Neck, anterior view
250. Muscles of the Tongue, left side
251. Superficial Lingualls and Intrinsic Vertical Fibres of the Tongue
252. Relative Positions of Litrinsic and Ilxtrinsic Muscles of the Tongue
253. Muscles of the Pharynx, external view
254. Muscles of tlie Soft Palate .....
255. Tlie Pn'vertebral Muscles .....
256. Plan of Dissciction of the Muscles of the Back .
257. Muscles of the Back — first, second, and part of the third layers
258. Muscles of the Back — dec^p layers ....
259. Plan of Dissection of Abdomen ....
2G0. The External Oblique Muscle ....
Quain
Quaiii
Quaai
LIST OF ILLUSTRATIONS.
PIG.
261. The Intertifil Oblique Muscle .
262. The Trausversalis, Kectus, and Pyramidalis
263. Transverse Section of Abdomen in Lumbar Region
264. The Diaphragm, under surface .
265. Plan of Lissection of Upper Extremity
266. Muscles of the Chest and Front of the Arm, superficial view
26 7. Muscles of the Chest and Front of the Arm, with the boundaries of th
268. Muscles on the Dorsum of the Scapula and the Triceps
269. Front of the Left Forearm, superficial muscles
270. Front of the Left Forearm, deep muscles
271. Posterior Surface of Forearm, superficial muscles
272. Posterior Surface of Forearm, deep muscles
273. Transverse Section through the Wrist, showing the Annular Ligaments
for the passage of the Tendons
274. Muscles of the Left Hand, palmar siu-face
275. Dorsal Interossei of Left Hand .
276. Palmar Interossei of Left Hand
277. Fracture of the middle of the Clavicle .
278. Fracture of the Surgical Neck of the Humerus
279. Fracture of the Humerus above the Condyles .
280. Fracture of the Olecranon
281. Fracture of Shaft of the Radius
282. Fracture of the lower end of the Radius
283. Plan of Dissection of Lower Extremity, front view
284. Muscles of the Iliac and Anterior Femoral Regions
285. Deep Muscles of the Internal Femoral Region .
286. Plan of Dissection of Lower Extremity, posterior view
287. Muscles of the Hip and Thigh .
288. Muscles of the Front of the Leg
289. Muscles of the Back of the Leg, superficial layer
290. Muscles of the Back of the Leg, deep layer
291. Muscles of the Sole of the Foot, first layer
292. Muscles of the Sole of the Foot, second layer .
293. Muscles of the Sole of the Foot, thu-d layer
294. Dorsal Interossei ....
295. Plantar Interossei ....
296. Fracture of the Neck of the Femur within the Capsular Ligament
297. Fracture of the Femur below the Trochanters .
298. Fracture of the Femur above the Condyles
299. Fracture of the Patella .
300. Oblique Fracture of the Shaft of the Tibia
301. Fracture of the Fibula, with displacement of the Tibia (Pott's fracture)
;
. 389
Quain
390
. 895
. 399
. 400
Axilla
. 403
. 406
. 411
. 414
. 416
. 419
and the Canals
. 420
. 422
.
. 424
.
425
Hind
426
do.
426
do.
427
do.
427
do.
428
do.
429
432
433
Quain
437
440
441
446
448
450
456
457
458
459
459
Hind
460
do.
460
do.
461
do.
461
do.
461
do.
462
Arteries.
302. The Arch of the Aorta and its branches
30*3. Plan of the branches of the Ai'ch of the Aorta
304. Surgical Anatomy of the Ai-teries of the Neck
305. Plan of the bi-anches of the External Carotid
306. The Arteries of the Face and Scalp
307. The Internal Maxillary Artery, and its branches
308. Plan of the branches of the Internal Maxillary Artery .
309. The Internal Carotid and Vertebral Arteries
310. The Ophthalmic Artery and its branches
311. The Arteries of the base of the Brain .
312. Plan of the branches of the Right Subclavian Artery .
313. The Scapular and Cli'cumfl ex Arteries .
314. The Axillary Artery and its branches .
315. The Surgical Anatomy of the Brachial Artery .
316. The Sui-glcal Anatomy of the Radial and Ulnar Arteries
317. Ulnar and Radial Arteries, deep view .
318. Arteries of the Back of the Forearm and Hand
319. The Abdominal Aorta and Its branches .
320. The Coeliac Axis and Its branches, the Liver having been
Omentum removed .....
321. The Cceliac Axis and its branches, the Stomach having been
verse Mesocolon removed
322. The Superior Mesenteric Ai'tery and Its branches
raised,
raised,
and the
and th
Lesser
Trans-
465
465
472
472
478
483
483
490
492
494
500
503
506
510
516
518
621
524
527
528
530
LIST OF ILLUSTRATIONS
S23. The Inferior Mesenteric Artery and Its branches
324. Arteries of the Pelvis ......
325. Variations in Origin and Course of Obturator Artery
326. The Internal Pudic Artery and its branches . . . ,
327. The Arteries of the Gluteal and Posterior Femoral Regions
328. Surgical Anatomy of the Femoral Artery
329. The Popliteal, Posterior Tibial, and Peroneal Arteries
830. Surgical Anatomy of the Anterior Tibial and Dorsalis Pedis Arteries
831. The Plantar Arteries, superficial view ....
332. The Plantar Arteries, deep view ....
PAGE
632
636
540
541
542
647
657
557
5G2
5G2
Yeins.
333. Veins of the Head and Keck .....
334. Veins of the Diploe, seen on removal of outer table of Skull .
335. Vertical Section of the Skull, showing the Sinuses of the Dura Mater
836. The Sinuses at the Base of the Skull ....
33 7. The Superficial Veins of the Upper Extremity .
338. The Vense Cavaa and Azygos Veins, with their Formative Branches
339. Transverse Section of a Dorsal Vertebra, showing the Spinal Veins
340. Vertical Section of two Dorsal Vertebra;, showing the Spinal Veins
341. The Internal, or Long Saphenous Vein and its Branches
342. The External, or Short Saphenous Vein
343. The Portal Vein and its Branches ....
. 566
Brescliet 669
. 671
. 673
. 574
. 577
Brescliet 580
do. 580
. 681
582
586
Quain
L y m p li a t i c s .
344. The Thoracic and Ptight Lymphatic Ducts ...... 589
345. The Superficial Lymphatics and Glands of the Head, Face, and Neck Mascagnr 591
346. The Deep Lymphatics and Glands of the Neck and Thorax . . do. 592
347. The Superficial Lymphatics and Glands of the Upper Extremity . do. 693
348. The Superficial Lymphatics and Glands of the Lov/cr Extremity . do_ 595
349. The Deep Lymphatic Vessels and Glands of the Abdomen and Pelvis do, 597
Nervous System.
350. The Spinal Cord and its Membranes ....
351. Transverse Section of the Spinal Cora and its Membranes
352. Spinal Cord, side View. Plan of the Fissures and Columns
353. Transverse Sections of the Cord ....
354. Medulla Oblongata and Pons Varolii, anterior surface .
355. Posterior Surface of Medulla Oblongata
356. Transverse Section of Medulla Oblongata
357. The Columns of the Medulla Oblongata, and their Connection with
the Cerebrum and Cerebellum ....
358. Upper Surface of the Brain, the Pia Mater having been removed
359. Vertical Median Section of Encephalon, showing the parts in the
middle line .......
360. Base of the Brain ......
361. Section of the Brain, made on a IcA^el with the Corpus Callosum
362. The Lateral Ventricles of the Brain ....
363. The Fornix, Velum Interpositum,
Ventricle
364. The Tliird and Fourth Ventricles
365. Upper Surface of the Cerebellum
866. Under Surface of the Cerebellum
367. Vertical Section of tht, Cerebellum
and middle or descending Cornu
Arnold
Quain .
Arnold
Arnold
Altered from
Arnold
After Sappey
of the Lateral
Arnold
603
603
605
606
611
611
612
613
617
618
620
623
624
626
629
633
6;i3
634
Cranial Nerves.
368. The Optic Nerve and Optic Tract . . . . . . .638
369. Course of the Fibres in tlie Optic Commissure .... Botrmnn 639
370. Nerves of tlic Oi-bit, seen from above ..... After Arnold 640
371. Nerves of the Oi-l)it and Oi)litliabiiic Ganglion, side view . . do. 641
872. The Course and Connections of the Facial Nerve in the Temporal Bone After Bidder 642
LIST OF ILLUSTRATIONS.
373. The Nerves of the Scalp, Face, and Side of the Neck .
374. Hypoglossal Nerve, Cervical Plexus, and their Branches .
375. Distribution of the Second and Third Divisions of the Fifth Nerve I
and Submaxillary Ganglion . ... . . J
376. The Spheno-palatine Ganglion and its Branches
377. The Otic Ganglion and its Branches
378. Origin of the Eighth Pair, their Ganglia and Communications
379. Course and Distribution of the Eight Pair of Nerves .
After Arnold
Bendz .
644
646
After Arnold 651
653
657
658
658
Spinal Nerves.
380. Plan of the Brachial Plexus ....
381. Cutaneous Nerves of Right Upper Extremity, anterior view
382. Cutaneous Nerves of Right Upper Extremity, posterior view
383. Nerves of the Left Upper Extremity, front view
384. The Suprascapular, Circumflex, and Musculo-spiral Nerves
385. The Lumbar Plexus and its Branches .
386. Cutaneous Nerves of the Lower Extremity, front view
387. Nerves of the Lower Extremity, front view
388. Cutaneous Nerves of the Lower Extremity, posterior view
389. Nerves of the Lower Extremity, posterior view
390. The Plantar Nerves .....
391. The Sympathetic Nerve ....
392. Ganglia and Nerves of Gravid Uterus .
.
671
.
673
.
674
.
676
.
678
Altered from
Q
uain
683
685
685
691
691
694
697
. After
R.
Lee
705
Organs of Sense.
393. Upper Surface of the Tongue .....
394. The three kinds of Pappillse of the Tongue, magnified
395. 396. Cartilages of the Nose .....
397. Bones and Cartilages of Septum of Nose, right side
398. Nerves of Septum of Nose, right side ....
399. A Vertical Section of the Eyeball, enlarged ......
400. The Choroid and Iris, enlarged .... Altered from Zinn
401. The Veins of the Choroid, enlarged ..... Arnold
402. The Arteries of the Choroid and Iris, the Sclerotic having been mostly ] ,
removed, enlarged ...... j
403. The Arteria Centralis RetiuEe, Yellow Spot, etc., the anterior half of the Eyeball
being removed, enlarged . . . . . ' .
404. 405. Vertical Sections of the Human Retina ....
406. The Crystalline Lens, hardened and divided, enlarged
407. The Meibomian Glands, etc., seen from the inner surface of the Eyelids
408. The Lachrymal Apparatus, right side .....
409. The Pinna, or Auricle, outer surface .....
410. The Muscles of the Pinna ......
411. A Front View of the Organ of Hearing, right Side
412. View of Inner Wall of Tympanum, enlarged ....
413. The Small Bones of the Ear, seen from the outside, enlarged .
414. The Osseous Labyrinth, laid open, enlarged ....
415. The Cochlea laid open, enlarged .....
416. Longitudinal Section of the Cochlea, showing the relations of the ]
Scalse, etc. ........ j
417. Floor of the Scala Media, snowing the Organ of Corti, etc.
418. The Membranous Labyrinth ......
Bowman
Arnold
do.
do.
Frey
Arnold
do.
Arnold
Scarpa
Arnold
Scemmerring
Arnold
1^1
710
711
713
714
716
717
718
720
721
724
726
728
729
730
731
733
735
738
740
C. Stewart 740
do.
do.
742
743
Organs of Digestion and their Appendages.
419. Sectional View of the Nose, Mouth, Pharynx, etc. ..... 746
420. The Permanent Teeth, external view ....... 747
421. The Temporary, or Milk Teeth, external view ..... 749
422. Vertical Section of a ]\Iolar Tooth . . . . . . .750
423. Vertical Section of a Bicuspid Tooth, magnified . . . After Retziiis 750
424. Vertical Section of the Lower Jaw of an early Human Foetus . Waldeyer 752
425. Dental Sac of a Human Embryo at an advanced stage of development Frey . 753
426. Cement and Dentinal Tubes ...... Waldeyer 753
427 to 430. Development of Teeth ...... Goodsir 754
C
465. Side View of the Thyroid and Cricoid Cartilages
466. The Cartilages of the Larynx, posterior view .....
467. The Larynx and adjacent parts, seen from above ....
468. Vertical Section of the Larynx and upper part of the Trachea
46 9. Muscles of Larynx, side view, riglit Ala of Thyroid Cartilage removed
470. Interior of the Larynx, seen from above, enlarged . . . Willis
471. Front View of Cartilages of Larynx : the Trachea and Bronchi
472. Ti-ansverse Section of the Trachea, just above its Bifurcation, with a bird's-eye view
of the interior ........
473. Surgical Anatomy of tlu; Laryngo-trachcal Region ....
474. A Transverse Section of tlie Thorax, showing the relative position of the Viscera, and
the reflections of the Pleura; .......
475. The Posterior Mediastinum, anterior view .....
476. The Posterior Mediastinum and Hoot of the Neck, posterior view
477. Front View of the Heart and Lungs ......
478. T1)0 Roots of the Lungs and Posterior Pulmonary Plexus, seen from behind .
479. IMinute Structure of Thyroid Chmd ..... Frcy
480. Minute Structure of Thymus Gland ..... do.
xxxiv LIST OF ILLUSTRATION^.
Fia. - FROM PAOR
431. The Salivary Glands . . . . . . . . .73 7
432. The Regions of the Abdomen and their contents (edge of Costal Cartilages in dotted
outline) . . . . . . . . . .762
433. The Reflections of the Peritoneum, as seen in a Vertical Section of the "I Altered from
Abdomen . . . . . . j Quain
434. The Mucous Membrane of the Stomach and Duodenum, with the Bile Ducts . . 768
435. The Muscular Coat of the Stomach ....... 769
436. Minute Anatomy of Mucous Membrane of Stomach '. . Dr. Sprott Boyd 770
437. Relations of the Duodenum . . . . .. . .772
438. Diagrammatic Section of a Villus ..... Watney 774
439. Two Villi, magnified . . . . . . . . .775
440. Transverse Section through three of Peyer's Follicles from the Rabbit Frey . 775
441. Patch of Peyer's Glands, from the lower part of the Ileum . . . .7 76
442. A portion of the same, magnified ..... Boehm . 776
443. Vertical Section of one of Peyer's Patches from Man, injected through Its ) -p
Lymphatic Canals ....... J ^"^^y ''^
444. The Caecum and Colon laid open, to show the Ilco-ctecal Valve . . . 777
445. Diagram of the relations of the Large Intestine and Kidneys, from behind . , 778
446. The relations of the Viscera and large vessels of the Abdomen, from behind .' . 780
447. Minute Structure of Large Intestine ..... C.Stewart 782
448. The Liver, upper surface . . . . . . . . 784
449. The Liver, under surface ........ 785
450. Longitudinal Section of an Hepatic Vein .... Kiernan 787
451. Longitudinal Section of a small Portal Vein and Canal . . do. 787
452.. Vessels of Lobules of Liver . . ... Klein . 788
453. Origin of Bile Ducts ....... Herring 789
454. A transverse Section of a small Portal Canal and its vessels . . Kiernan 789
455. The parts in the Gastro-hepatic Omentum . . . . . .791
456. The Pancreas and Its Relations ....... 792
457. Transverse Section of the Spleen, showing the Trabecular Tissue, and the Splenic
Vein and Its branches . . . . . . . . 7 94
458. The Malpighian Corpuscles, and their relation with the Splenic Artery and Its branches 795
459. One of the Splenic Corpuscles, showing Its relations with the Bloodvessels . . 796
460. Transverse Section of the Human Spleen, showing the distribution of the Splenic
Artery and its. branches . . . . . . .797
Organs of Circulation.
4G1. Front View of the Thorax, showing the relation of the Thoracic Viscera to the walls
of the Chest .• . . . . . . . . .800
462. The Right Auricle and Ventricle laid open, the anterior walls of both being removed . 802
463. The Left Auricle and Ventricle laid open, the anterior walls of both being removed . 80G
464. Plan of the Foetal Circulation ........ 811
Organs of Yoice and Respiration.
814
815
817
818
820
820
823
825
826
828
829
830
832
835
837
LIST OF ILLUSTEATIONS.
The Urinary and Generative Organs.
481. Vei'tical Section of the Kidney. . . .
482. Diagram of the Hilum, Sinus, and Pelvis of the Kidney
483. Minute Structure of Kidney .......
484. Dia2;rammatic representation of the Bloodvessels in the substance of the ] t , . „ . „
Cortex of Kidney | ^^^wig 840
485. The various views as to the Epithelium of the Malpighian Body
486. Diagram of Looped Tubes of llenle ......
487. Pyramid of Ferrein ........
488. Transverse Section of Pyramidal Substance of Kidney . . . Klein
489. Longitudinal Section of Straight Tube ..... do.
490. Longitudinal Section of Henle's Descending Limb ... do,
491. Diagrammatical Sketch of Kidney . . . ■ .
492. A portion of Fig. 491 enlarged .......
493. Coi-tical Portion of Human Suprarenal Body .... Frey
494. Transverse Section through Cortical Substance of Human Suprarenal Body do.
495. Vertical Section of Bladder, Penis, and Urethra ....
496. The Bladder and Urethra laid open, seen from above ....
497. Structure of the Corpus Cavernosum ..... Langer
498. The Testis, in situ, the Tunica Vaginalis having been laid open
499. Plan of a Vertical Section of the Testicle, to show the arrangement of the Ducts
500. Base of the Bladder, with the Vasa Deferentia and Vesiculas Seminales HcCller
501. The Vulva, External Female Organs of Generation ....
502. Section of Female Pelvis, showing position of Viscera ....
503. The Uterus and its Appendages, anterior view .... Wilson
504. Section of the Ovary of a Virgin . . . . ,
505. Section of the Graafian Vesicle . . . . . After Von Baer
506. Inguinal Hernia, Superficial Dissection .....
507. Inguinal Hernia, showing the Internal Oblique, Cremaster, and Spermatic Canal
508. Inguinal Hernia, showing the Transversalis Muscle, the Transversalis Fascia, and the
Internal Abdominal Ring .......
509. Femoral Hernia, Superficial Dissection .....
510. Femoral Hernia, showing Fascia Lata and Saphenous Opening
511. Femoral Hernia, Iliac portion of Fascia Lata removed, and Sheath of Femoral Vessels
and Femoral Canal exposed .......
512. Hernia; the Belations of the Femoral and Internal Abdominal Rings, seen from
within the Abdomen, right side ......
513. Plan of Dissection of Perineum and Ischio-rectal Region
514. The Perineum ; the Integument and Superficial Layer of Superficial Fascia reflected
515. The Superficial Muscles and Vessels of the Perineum ....
516. Deep Perineal Fascia ; on the Left Side the Anterior Layer has been removed
517. A View of the Position .of the Viscera at the Outlet of the Pelvis
518. A Transverse Section of the Pelvis, showing the Pelvic Fascia . After Wilson
519. Side View of the Pelvic Viscera of the Male Subject, showing the Pelvic and Perineal
Fascia3 .........
520. The Pelvic Fascia ........
PAGE
838
839
840
841
842
842
843
844
844
844
844
849
852
858
862
863
864
867
869
874
874
874
879
881
890
892
896
898
899
900
903
904
905
906
LANDMARKS, MEDICAL XKT) SURGICAL.
521. Outline of the Heart, its Valves, and the Lungs
522. Opisthotonos . . . . .
After Bell
924
928
ANATOMY, •
DESCRIPTIVE AND SURGICAL.
INTRODUCTION.
GENERAL A]N" ATOMY.
The fluids of tlie body, wliicli are intended for its nutrition, are tlie lympli, tlie
cliyle, and the blood. There are other fluids also which partially subserve the
same purpose, as the saliva, the gastric juice, the bile, the intestinal secretion; and
others which are purely excrementitious, as the urine. All these fluids form a
part of the bulk of the body under ordinary circumstances. But there is no
need to describe the rest in this place, since they are the secretions of special
organs, and are described, as far as is judged necessary for the purpose of this
work, in subsequent pages. "We shall here speak first of the blood, and next
of the lymph and chyle.
THE BLOOD.
The blood is a fluid holding a large number of minute cells or corpuscles in
suspension. Its general physical characters are so well known that we need
merely say that it is of a dark red or purple color in the veins, and of a bright
red or scarlet in the arteries ; that it is viscid, drying rapidly, and with a clammy
feeling ; salt to the taste, slightly alkaline, and with a specific gravity of about
1055.
General Composition of the Blood. — On standing, blood, under ordinary cir-
cumstances, soon separates into two parts — a fluid called the " seruni^'' and a clot
or " coagulum^ The latter is not merely the cells or blood-corpuscles spoken of
above as held in suspension, and which have subsided out of the fluid, but con-
sists besides of fibrin which has been held in solution in the fluid blood, and
which in its solidification has enclosed and implicated the blood-corpuscles as
they subside.
The blood is thus seen to consist naturally of two parts, the plasma^ or liquor
sanguinis.^ a fluid rich in fibrin, and the blood-cells, or blood-corpuscles ; and
when drawn from the body, of two parts composed differently to the above, — ■
viz. the clot, which comprises the blood-corpuscles and the fibrin of the plasma;
and the serum, which consists of the remainder of the plasma.
The hlood-corpuscles, hlood-dishs, or hlood-glohules, as they are more commonly
called, are of two kinds, the red and the white. The red glolmles are far the
more numerous, and are those which are always intended when the expression
blood-disks or blood-globules is used without anv other oualification. They
3 "^ ' (33)
34
GENERAL ANATOMY.
are said to be in man about tliree or four hundred times as numerous as tbe
wbite (Harley) ; by others only fifty times as numerous (Todd and Bowman).'
They differ very much in size and shape in different animals (Fig. 1). In man
their size varies considerably, even in the same drop of blood, between the
limits of 4o'oo
and os'oo of an inch in diameter, the average being about gg'o-Q
[Fig. 1.
Fis:. 2.
Corpuscles of Frog's blood : 1, 1, red corpuscles seen on
their flattened face ; 2, the same turned nearly edgeways ;
3, colorless corpuscles ; 4, red corpuscles altered by dilute
acetic acid.]
Human blood-globules ; a, seen from the
surface ; b, from the side; c, united in rou-
leaux; d, rendered spherical by water; e,
decolorized by the same ; /, blood-globules
shrunk by evaporation.
(Todd and Bowman). They are circular disks, bi-concave in profile, having a
slight central depression, with a raised border (as seen in Fig. 2, l). Their
color appears of a faint yellow when they are seen singly, but it is to their
aggregation that the blood owes its red hue. Human blood-disks present no
trace of a nucleus. They consist of a tough elastic transparent stroma uni-
formly pervaded by a coloring matter called hsemoglohin. When the blood is
circulating, under the microscope, in one of the lower animals, the blood-
globules are seen to be separate from each other, and are also sejDarated from the
wall of the vessel by an interval or "lumen." Doubtless the same is the case in
the human body ; but when drawn and examined on a slide without reagents,
the blood-globules often collect into heaps like rouleaux of coin (Fig. 2, c). Their
shape is very soon influenced by the medium in which they are placed, and by
the specific gravity of that medium. In water they swell up, lose their color,
and cease to be visible, leaving the white corpuscles in the field. Solutions of
salt or sugar, denser than the serum, give them a stellate appearance ; and the
usual shape may be restored by diluting the solution to the proper point. A
solution of the proper strength merely separates the blood-globules mechanically,
without changing their shape.
There can be no doubt that the difference in color between arterial and venous
blood must bo due to some minute difference in the red blood-globules ; and it
is also in the highest degree probable that the chemical differences between
these two kinds of blood are due, in part at least, to such differences ; but the
change has not hitherto been rendered perceptible either to the microscope or
to chemical analysis. At the same time, the researches of Professor Stokes^
show that the coloring matter of the blood produces different effects on the solar
spectrum, according as it is in a more or less oxidized condition ; and it is in the
highest degree probable that the same change in the oxidation of the contents
of the blood-globules produces the difference of color between arterial and
venous blood.
The human white corpuscles (Fig. 3) are rather larger than the red, and have
an irregular or granular surface. A nucleus becomes perceptible on the addi-
tion of acetic acid. They are very similar to, if not identical with, the cor-
' ITirf. pills th(> prnportion ns low as I : 17G1 (luring- fasting', iuid 1 : GOT) or 1 :42!) after food
(Kiillikcr). Ven:cK('ction, l)y witlidravviiicf so much larijcr a ])ropor1ion of the red globules, and
also by favoring the absorption of lymphatie fluid into the blood, much increases the relative pro-
portion of the while corpuscles, so that Kiilliker asserts that in the horse, after enornunis venie-
section (up to .50 lbs.) the colored and colorless corpuscles ujipear equally luunerous.
" rroceedings of Royal Society, 18G4.
THE BLOOD. 35
puscles of the lympli and cliyle, tliougli somewliat more acted upon by acetic
acid than the latter. Their proportion appears to vary considerably in differ-
ent parts of the circulation, being much larger in the blood of the splenic vein
and hepatic vein than in other parts of .
the bod}^, while in the splenic artery Fig. 3.
they are very scanty. The colorless ^.^ -"^
corpuscles bear a strong resemblance <iy^ ^& .-.^ ^^.. .--^
also to the cells found in pus. It is well O i0^^ ^ ® -^ ti^"' "
known that these colorless corpuscles ^ W ''^' ^.:v^», -^ /^^^
have the remarkable properties of loco- _^_^^_ "" ^^ '^^ ^^ i^
motion and of "amoeboid" changes, so 0^^^^, „. ^P @ 4^^!^^ O
flmt p,-5rfl,rm'np,rl rlnrino- lifp,_ tliRV mav wKI^S^ ^;:-.,I .!;-5Si-» ^P ^"^ ~'H«a .SS
that, examined during life, they may fp^^ ^
show various shapes. (Fig. 4.) ^ -0? ^^ W
From the fact that cells exactly like , ., , '^^ ^ ^,^''t' ,
. -, , , , . -^ a, wliite corpuscles of human blood ; d, red corpus-
the colorless corpuscles are benig con- ^les. (High power.)
stantly furnished to the blood by the
ducts of the lymphatic glands, the chyle-ducts (and even the liver in the foetus),
and also from their varying proportion in different parts of the circulation, and
Fiff. 4.
Human colorless blood-corpuscle, showing its successive changes of outline within ten minutes when kept
moist on a warm stage. (Schofleld.)
in different pathological conditions, the colorless corpuscles are usually re-
garded— -with, at any rate, considerable probability, — as an earlier stage of the
colored blood-disks.
Fat-granules are seen in the blood of the lower animals, and occasionally in
the blood of pregnant women ; also, according to Kolliker, in other persons
after the abundant use of milk or brandy, as well as in those who are fasting ;
which he attributes, in the latter case, to the absorption of the fat of the body.
But, under ordinary circumstances, the granular base of the chyle, poured into
the blood, through the veins at the root of the neck, disappears as the blood
passes through the lungs.
Gases of the Blood. — A given quantity of blood contains rather less than half
the same volume of gases. These are carbonic acid, oxygen, and nitrogen. The
relative quantity is roughly stated thus : Carbonic acid about two-thirds of the
whole quantity of gas, oxygen rather less than one-third, nitrogen below one-
tenth (Huxley).^ The nitrogen is unimportant. It (or at least the greater part
of it) is merely absorbed from the atmosphere under the pressure to which the
blood is exposed, and can therefore be mechanically removed, as can also a part
of the oxygen and carbonic acid ; but the greater part of the oxygen is in loose
chemical combination with the haemoglobin of the blood-corpuscles, and the
greater part of the carbonic acid seems to be in stable chemical combination
with the salts of the serum, though a certain proportion is also combined loosely
with the blood- globides.
The experiments by which these facts are proved will be found in the physio-
logical treatises.
The fluid part of the blood, the liquor sanguinis^ or plasma, is again composed
of a permanently fluid portion — the serum — and of fibrin, which coagulates
' The quantity of gases contained varies, of course, with a grreat number of different conditions,
and especially according as the blood is arterial or venous. Hermann states that the proportion
of oxygen varies from 16.9 vols, per cent, in arterial to 5 9 per cent, in venous blood, that arterial
blood contains on an average about 30 vols, per cent., and venous about 35 per cent., of carbonic
acid; and this author places the proportion of nitrogen as low as from 1 to 2 vols, per cent.
36
GENERAL ANATOMY.
spontaneously wlien out of tlie body, but wliicli is held in solution during life.
The fibrin can be separated from blood after it has been drawn by whipping it
with twigs, to which the fibrin as it coagulates adheres. The fibrin does not
exist as such in the blood, but is formed during coagulation by the union of two
substances (fibrino-plastin and fibrinogen) which exist separate in the blood.
For the experiments which prove this fact, and for the account of the substances
themselves, as well as the properties of the blood and the phenomena of its
coagulation, I must again refer to the treatises on Physiology. The liquor san-
guinis may be obtained free from the red -corpuscles by filtration in animals
whose blood-globules are sufficiently large, or in mammalia by exposing the
blood to a freezing temperature till the corpuscles have subsided. By this pro-
cess, or by removing a portion of the clear liquor which is found above the
buff'y coat of inflammatory blood just after the latter has formed, the plasma
may be obtained, and will then separate by coagulation into a colorless clot of
fibrin and saline fluid. The fibrin-clot consists of interlacing structureless
strings, which contain in their meshes some white corpuscles accidentally in-
closed in them.
The fluid left after the coagulation of the fibrin, which is the serum of the
blood properly so called, is yellowish, and contains so much albumen that it
solidifies almost completely on being heated. It is alkaline from the presence
Fiff. 5.
Blood-crystals. A, triliedral crystals from blood of guinoa-piff. B, pontat^onal crystals from hinod of
squirrel. C, octahedral crystals from blood of rat and mouse. IJ, liacmatin crystals ir.om human blood. E,
hajmatoidin crystals from an old apoplectic clot. F, hicmin crystals from blood treated with acetic acid.
of free soda and carbonate of soda. The chemical composition of the blood is
complex, as might be anticipated of a fluid from which all the various tissues
of the body are to be formed ; and it must of course vary in various parts of
LYMPH AND CHYLE. 37
the circulation. Tlie following seems to be as accurate an analysis as possible.
It is quoted in Carpenter's "Physiology," by Power, from M. Gorrup-Bezanez,
who procured two samples of the same person's blood, and had them analyzed
by himself and three other competent chemists. The separate analyses are given,
but the variations are too slight to be worth quoting. The following were M.
Gorrup-Bezanez's results : — •
1st Spec. 2d Spec.
Water 796.93 783.63
Solid matters 203.07 216.37
Fibrin 1.95 1.56
Corpuscles 103.23 115.12
Albumen 70.75 62.74
Extractive matter and salts ....... 27.14 36.95
The crystals which form in the blood under certain circumstances and when
treated by certain reagents ought to be described, in consequence of their im-
portance as a means of distinguishing human from other kinds of blood. They
are of three kinds : 1. Hasmatin crystals, found in normal blood, particularly
in the spleen. These are procured by the addition of a little water, or by agi-
tating the blood with ether, by either of which means the blood-corpuscles are
ruptured, and their contents crystallize on evaporation. 2. Hsematoidin crys-
tals, found in old clots. 3. Hcemin crystals, formed by mixing dried blood with
an equal quantity of common salt and boiling it with a few drops of glacial
acetic acid till the whole has dissolved. A drop of the mixture placed on the
slide will show the crystals on cooling.
Fig. 5 shows these three forms of crystals from human blood, together with
some from the lower animals, for comparison.
The importance of being acquainted with the crystals found in human blood
is obvious, and more particularly those which can be obtained from dried blood ;
since in this way old blood-stains can be recognized as being human or other-
wise, even long after their formation. The spectrum analysis, however, is said
to be a more delicate test of fresh blood.
LYMPH AND CHYLE.
The lymph and the chjle are almost identical in constitution, though the pro-
portion of their constituents varies in different parts of the vascular system. The
lymph is the secretion of a system of vessels and glands, to be more fully described
in the sequel, which takes up from the worn-out
tissues that which is still available for purposes of Fig- 6.
nutrition and returns it into the veins close to
the heart, there to be mixed with the mass of
the blood. The chyle is a fluid secreted by the
villi of the small intestines from the food. It is
intermingled with the lymph, and is poured into
the circulation through the same channels.^ (See
the description of the Thoracic Duct, Lacteals,
and Ductus Lymphaticus dexter, in the body of
the work.)
On microscopical examination, chyle displays ^ ' ' >^^ ^ _
besides the lymph-corpuscles a large number of J zj ^ ^-^ q
fatty granules, "the granular base of the chyle" - ^P "^ -'-
(Fig. 6, a), oil globules, free nuclei, and a few chyie from tiie lacteais.
' It may not be amiss to remind the student that the lacteal or chyliferous vessels only convey
a portion of the nutritions matter from the food, and this only during digestion. At other times
they seem to act precisely as ordinary lymphatics.
38 GENERAL ANATOMY.
red blood- globules. The white color of tlie cbyle is due to tbe abundance of tlie
molecular base. These molecules are almost or entirely absent in lymph.
In other respects lymph and chyle are indistinguishable by microscopic
examination, but in external appearance they are very different.
Chyle is a milk-white fluid, which coagulates spontaneously, and then on
standing separates more or less completely into a clear part, the liquor chyli^
which is identical with the liquor sanguinis, and a thinnish jelly-like clot, con-
sisting of fibrin in which chyle-corpuscles and the fatty molecules are entangled.
Its analysis, as given by Dr. G. O. Eees^ from the chyle of a criminal examined
shortly after his execution, and in whom the thoracic du.ct was found distended
with chyle, is as follows : —
Water 90.48
Albumen, with traces of fibrinous matter 7.08
Aqueous extractive .56
Alcoholic extractive or osmazome ........ .52
Alkaline chloride, carbonate and sulphate, with traces of alkaline phos-
phate and oxide of iron . .44
Fatty matters .92
100.00
Lymph, as its name implies, is a watery fluid. In the lymph the molecular
base is absent, and the lymph-corpuscles are very few in number, and indeed
are said by Kolliker to be absent in the smaller vessels. According to the
same author, the size of the lymph -globules increases as the fluid ascends higher
in the course of the circulation. In this view the lymph is at first a mere albu-
minous fluid, and the chyle at first a mere albumino-fatty fluid, the cells in both
being produced during the passage of the fluid through the glands (lymphatic
or mesenteric, as the case may be), and being further elaborated, and even new
cells produced by the division of the old ones, in the course of the circulation.
The presence of mature blood-globules in the lymph or in the chyle is regarded
by most authors as accidental — i. e. produced by the manipulation of the dis-
sector ; but Dr. M. Foster says that the pink color seen on the surface of clotted
chyle, even when no blood is mixed with it, is due to immature red corpuscles
proper to the chyle.
The lymph-corpiiscles, as seen in the above figure, are in all essential respects
the same in the chyle, the lymph, and the blood, where they have been de-
scribed above as the colorless blood-corpuscles. In the chyle and lymph, however,
they vary very much in size. In some cases several younger cells are found
inclosed in the original corpuscles.
CELLS AND PEOTOPLASM.
All the solid tissues of the body are originally developed out of cells con-
taining a matter now usually styled protoplasm, and many such cells persist in
mature structures. In the higher organisms all such cells are nucleated — ^. e.
they contain in their interior a smaller cell or nucleus, which frequently presents
in its centre a nucleolus. The protoplasm is situated, around the nucleus, and
is usually inclosed in a limiting membrane or cell-wall. Protoplasm (sarcode,
blastema, germinal matter, or bioplasm) is usually granular, sometimes hyaline,
is indistinguishable in its chemical relations from albumen, of a semi-fluid, viscid
consistence, and distinguished by its vital properties of amxehold motion (of which
cihary movement may be taken to be a variety), nutrition — that is, the power
of attracting to itself the materials of growth from the surrounding matter —
and reproduction, by means of which fresh cells are produced either by segmen-
tation or budding. These processes commence in the nucleus, which is a special
' Phil. Trans. 1842, p. 82.
CELLULAR AND FIBROUS TISSUE.
39
collection of protoplasm marked off by a definite outline from the rest of tlie
cell, and distinguished from it by resisting the action of acids and alkalies which
destroy or render invisible the body of the cell, and by imbibing the stain of
carmine, hgematoxyline, &c. In the reproduction of cells by segmentation the
nucleus splits ; in that by germination it sends off a process ; and thus new
nuclei are produced which are surrounded by their own cell substance, and
gradually detach themselves from the parent cell. The most remarkable pro-
perty of cells is that of growth, development, or differentiation, by means of
which the most various solid tissues, or even fluids containing cells, are de-
veloped out of cells originally to all appearance identical.
The death of cells is accomplished either by their mechanical detachment
from the surface, preceded possibly by their bursting and discharging their con-
tents, or by various forms of degeneration, fatty, pigmentary, or calcareous.
Cells are held together either by anastomosis of their processes, by intercel-
lular substance, semi-fluid, hyaline, or of various higher forms which are, in fact,
metamorphosed cells, or by direct contact of their walls.^
CELLULAR AND FIBROUS TISSUE.
The cellular or areolar tissue is so called because its meshes are easily dis-
tended, and thus separated into cells or spaces which all open freely into each
other, and are consequently easily blown up with
air, or permeated by fluid, when injected into any
part of the tissue. Such spaces, however, do not
exist in the natural condition of the body, but the
whole tissue forms one unbroken membrane com-
posed of a number of interlacing fibres, variously
superimposed. Hence the old term " the cellular
membrane" is in many parts of the body more appro
priate than its more modern equivalents. The chief
use of the cellular tissue is to bind parts together ;
while by the laxity of its fibres and the permeability
of its areolje it allows them to move on each other,
and afibrds a ready exit for inflammatory and other
effused fluids. It is consequently often denominated
connective tissue^ and this term is still more appro-
priate to the fibrous tissue which forms the bond of
connection between the intimate elements of solid
organs ; in which more restricted sense the term is
often used in modern works. The areolar tissue
consists essentially of two forms of fibrous tissue,
the white and yellow^ intermixed in varying propor-
tions, together with a great quantity of capillary
vessels, nerves, and lymphatics, and in most situa-
tions it contains fat. The cellular tissue is continuous over the whole body ; so
that fluid, and especially air, when injected forcibly into it — as from a wound
of the lung or bowel — may be diffused into the remotest parts.
The ivhite fibrous tissue (Fig. 8) consists of bundles of wavy fibres interlacing
with each other, each composed of minute filaments, or fihrillee^ which appear
Portion of areolar tissue, inflated
and dried, showing tlie general cha-
racter of its larger meshes. Each
lamina and filament here repre-
sented contains numerous smaller
ones, matted together by the mode
of preparation. (Magnified twenty
diameters.)]
homoafeneous.
and measure from go no?)
to unlrni of an inch in diameter. The
2 0 0 c c
larger fibres have no definite size, but are supposed to be solid masses formed
by an agglutination, as it were, of the ultimate fibrill^. Acted upon by acetic
acid, the white fibrous tissue swells up into an indistinct uniform mass, which
' The above is abbreviated from the admirably clear description in Kirkes's " Physiology" by
Morrant Baker.
40
GENERAL ANATOMY
gradually becomes indistinguish-
able; and in tlie areolar tissue,
when thus treated, the yellow
elastic element comes alone into
view.
The yellow elastic fibrous tissue
(Fig. 9) is an aggregation of
fibres, which are considerably
larger in size than the fibrillaB of
the white fibrous element, vary-
ing from 5 4^7^
^ ^o 4o'(j-o of aninch
V/hite fibrous tissue. (High power.)
in diameter (Harley). The fibres
branch and anastomose freely
with one another. They are homogeneous in appearance, with dark borders,
and are usually seen curled up at their broken ends. They remain unaltered
by acetic acid.
Fitr. 9.
Fiff. 10.
Fig. 11.
stellate formative
cells of fine elastic
fibres, from the ten-
do-Achillis of a new-
born child. (Magni-
fied 350 times.)
Yellow elastic tissue. (High i)ower.)
Tormative cells of areo-
lar tissue from sheejj's
embryo. (Magnified 350
times.) a, Cell without
any indication of fibrils;
b, with commencing, and
c, with distinct fibrils
Each of these elements of the connective tissue is developed from cells. Kolli-
ker describes the yellow elastic fibres as developed from the stellate branching
corpuscles, which may sometimes be found free in the areolar tissue, and which
V^irchow has denominated "connective-tissue-corpuscles" (Fig. 10); while the
white fibrous tissue is formed from the coalescence of fusiform cells, which
elongate into fibrillar as shown by Fig. 11.
The two tissues just described arc very widely distributed in the body, espe-
cially the white fibrous tissue. This latter forms nearly the whole of all the
firm* investing membranes; viz., the muscular fasciio, the periosteum, the invest-
ments of the various glands (such as the tunica albuginea testis, the capsule of
ADIPOSE TISSUE. 41
tke kidney, &c.), tlie investing slieatli of tlie nerves (neurilemma), and of various
organs, as the penis and tlie eye (sheath of the corpora cavernosa and spongiosum,
sclerotic and choroid). Into all these parts, however, the elastic tissue enters in
greater or less proportion. The tendons and most of the ligaments are also
formed almost entirely of the white fibrous tissue, but with some elastic fibres
intermixed. The basis of the serous and mucous membranes is formed of con-
nective tissue, disposed in a layer. The common subcutaneous cellular or cel-
lulo-adipose tissue has been taken above as the typical form from which to
describe connective tissue. Connective tissue also enters largely into the forma-
tion of the bloodvessels, glands, and, in fact, almost every organ in the body.
The organs which are formed almost exclusively of the yellow elastic tissue are
the ligamenta subflava of the vertebrae, the elastic ligaments of the larynx, the
longitudinal elastic fibres of the trachea, the elastic layer of the middle coat of
the arteries, and in quadrupeds the ligamentum nuchas.
Free cells are found in the areolar tissue, as indicated above. The chief forms
are the spindle-shaped and the stellate, but numerous intermediate forms are
described by recent observers ; and of late much interest has been excited by
Von Recklingshausen's discovery in the cellular tissue of cold-blooded animals
of "wandering cells," or cells endowed with the power of automatic motion, and
of changing their shape. These cells appear identical with the white globules
of the blood; and it would seem from the researches of Strieker, Cohnheim,
and others, that the walls of the capillary vessels are permeable to the latter
bodies, which are thus allowed to escape into the cellular tissue, there to undergo
development, normally into the natural cells and cellular tissue, or abnormally
into the corpuscular forms of lymph and pus, according to circumstances.'
Treated with nitrate of silver, the cellular tissue is seen to consist of spaces
formed by the fibres, united together by a homogeneous cement or "ground
substance," and filled by the cellular elements, which contain the protoplasm
out of which the whole is developed and regenerated.
Two special kinds of cellular tissue must be described — the mucoid^ and the
lymphoid or retiforin. The mucoid or gelatinous tissue exists chiefly in the
"jelly of Wharton," which forms the bulk of the umbilical cord, and in some
other tissues of the foetus ; but in the adult body also the vitreous humor of the
eye is formed of gelatinous cellular tissue. This tissue is formed of rounded
nucleated cells separated by a transparent jelly-like substance which in the
umbilical cord shows traces of fibrillation.
Retiform, adenoid, or lymphoid connective tissue is found extensively in many
parts of the body, often surrounding the minute bloodvessels, and forming the
commencement of lymphatic channels. It is formed of an interlacement of very
fine fibres, at the nodal points of which stellate cells are situated. The interstices
of the fibres are filled with the rounded granular corpuscles of the lymph. The
neuroglia^ or fine gelatinous connective tissue which supports the nervous ele-
ments in the cerebro-spinal axis and in the retina, is regarded as a modified
form of the retiform connective tissue.
ADIPOSE TISSUE.
The common cellular membrane contains a variable quantity of adipose tissue.
This tissue is found also in various parts of the viscera — as the mesentery, the
surface of the heart, &c. — and fat enters largely into the formation of the marrow
of the bones. There is, however, a difference which should be attended to
between mere fat and adipose tissue. Adipose tissue consists of a number of
vesicles formed by an extremely delicate structureless membrane, round or
' On this subject reference may be made to "Von Recklingshausen, in Virchow's Archiv, Bd.
xxviii., and Eollett, in Strieker's Human and Comparative Histology, translated by Power,
chap, ii., where the reader \nll find references to Strieker, Cohnheim, Kiihne, and others.
42
GENERAL ANATOMY
splierical where tliej liave not been subject to pressure; otlierwise, variously
flattened. Tliey are supplied and held together by capillary bloodvessels, and
fine connective tissue, and each vesicle is filled with fat.
iff. 12.
Bloodvessels of fat. 1. Minute flattened fat-lobule, in which the vessels only are represented. 3. Terminal
artery. 4. Primitive vein. 6. Fat-cells of one border of the globule separately represented. (Magnified 100
diameters.) 2. Plan of arrangement of capillaries on exterior of fat-cells, more highly magnitied.]
Fat is an unorganized substance, consisting of liquid oily matter (glycerine)
in combination with certain fatty acids, stearic, margaric, and elaic. Sometimes
the acids separate spontaneously before the fat is examined, and are seen under
the microscope in a crystalline form, as in the figure. Bj^ boiling the tissue in
ether or strong alcohol, the fat may be extracted from the vesicle, which is then
seen empty and shrunken.
Fig. 13.
Adipose tissue, a, starlikc api)carance, from crystallization of fatty acids. (High power.)
Besides the fully-formed fat-cells above described, others may occasionally be
found in the course of formation, especially in cases of sudden death during
robust health. They are described by Eollett as, in the first stage, small round
granular cells, ]')rovidcd with a roundisli nucleus, into the interior of which a
strongly-refracting drop of fat is then secreted, which is at first surrounded by
a ring of the granular matter, and gradually increases so as to fill the cell. As the
granular matter becomes less and less, the nucleus, which can at first be easily
CARTILAGE.
43
recognized, becomes less perceptible, but according to this autlior can always be
brought into view by appropriate reagents. Fat is said to be first detected in
the human embryo about the fourteenth week.
In various parts of the body pigment is found, viz. in the hairs, in the iris
and choroid coat of the eye, in the lungs, in the nerve-cells, in the rete mucosum
in the dark races, and in some parts of the body — -such as the areola of the
nipple. Such parts are of dark color even in the fair races, except Albinoes, in
whom pigment is absent. Pigment-cells are also found in the blood, according
to Yirchow.
In many situations the color is produced simply by the presence of dark
granules scattered about without any definite arrangement ; in the inner layer
of the choroid coat (or external layer of the retina) the pigment forms a regular
layer of hexagonal nucleated cells filled with pigment-granules ; in other parts
the pigment is contained in branching cells, probably the connective-tissue-cor-
puscles filled with pigment-granules ; and in most situations, such as the nerve-
cells and the epidermis, the pigment-granules form a greater ■ or less element in
the contents of the nucleated cells of the part. (Fig. 32.) In the dark races
the color of the skin is due to the accumulation of pigment in the deeper layers
of the epidermis — the rete mucosum.
CARTILAGE.
Cartilage is a non-vascular structure which is found in various parts of the
body — in adult life chiefly in the joints, in the parietes of the thorax, and in
various tubes, such as the air-passages, nostrils, and ear, which are to be kept
permanently open. In the foetus at an early period the greater part of the
skeleton is cartilaginous. As this cartilage is afterwards replaced by bone, it
-is called temporary^ in opposition to that which remains unossified during the
whole of life, and which is called permanent.
Cartilage is divided according to its minute anatomy into true or hyaline
cartilage, fibrous, or fibro- cartilage, and yellow, or elastic, or reticular cartilage.^
The various cartilages in the body are also classified according to their function
and position, into articular, interarticular, costal, and membraniform.
True cartilage, which may be taken as the type of this tissue, consists of a
gristly mass, of a pearly bluish color, enveloped in a fibrous membrane, the
perichondrium^ from the vessels of
which it imbibes its nutritive fluids, j^ig- ^^^
being itself destitute of bloodvessels ;
nor have nerves been traced into it.
Its intimate structure is very simple.
If a thin slice be examined under
the microscope, it will be found to
consist of cells of a rounded or angu-
lar shape, with nucleus and nucleo-
lus, lying in groups, surrounded by
a granular or almost homogeneous
matrix. By boiling the cartilage
for some hours, and treating it with
acetic acid, the cell-membrane which lines the cavity in the matrix may be made
visible.
Human cartilage cells, from the cricoid cartilage.
(Magnified 350 times.)
' Besides these varieties of cartilage met with in the adult human subject, there is a variety
called the cellular, which consists entirelj' or almost entirely of cells, united in some cases by a
network of very fine fibres, in other eases apparently destitute of any intercellular substance.
This is found in the external ear of the rat and some other animals, and is present in the chorda
dorsalis of the human embryo, but is not found in any other human structure.
44
GENERAL ANATOMY.
Fiar
By tlie application of certain reagents or bj digestion in warm acidiilated
water tlie matrix is found to be arranged in the form of concentric rings around
the cartilage-cell, forming what is described by some authors as the cartilage-
capsule, or cell-territory ; and EoUet describes a system of dark lines, running
in a straight direction through the matrix and often connecting the several cell-
cavities with each other, which are brought into view by the action of osmic
acid. These are regarded by some anatomists as nutritive canals.
The articular cartilages, the temporary cartilages, and the costal cartilages,
are all of the hyaline variety. They present minute differences in the size and
shape of their cells, and in the arrangement of the matrix. In the articular
cartilages, which show no tendency to ossification, the matrix is finely granular
under a high power ; the cells and nuclei are small, and are disposed parallel to
the surface in the superficial part, while nearer to the bone they become vertical.
Articular cartilages have a tendency to split in a vertical direction, probably
from some peculiarity in the intimate structure, or arrangement of the compo-
nent parts, of the matrix. In disease this tendency to a fibrous splitting becomes
very manifest. Articular cartilage in the adult is not covered by perichondrium,
at least on its free surface, where it is exposed to friction, though an epithelial
layer can be traced in the foetus over the whole surface of the cartilage, and in
the adult over a small part of its circumference, continuous with the epithelium
of the synovial membrane. This is probably the remains of an investing mem-
brane which is worn away in after-life by the action of the joint. Articular
cartilage forms a thin incrustation upon the joint surfaces of the bones, and its
elasticity enables it to break the force
of any concussion, whilst its smooth-
ness affords ease and freedom of move-
ment. It varies in thickness according
to the shape of the bone on which it lies :
where this is convex, the cartilage is
thickest over the convexity where the
greatest pressure is received, and the
reverse is the case in the concavities of
the joints. Articular cartilage appears
to imbibe its nutriment partly from the
vessels of the neighboring synovial mem-
brane, partly from those of the bone
upon which it is implanted. Mr. Toyn-
bee has shown that the minute vessels
of the cancellous tissue, as they approach
the articular lamella, dilate, and, forming-
arches, return into the substances of the
bone.
Temporary cartilage, and the process
of its ossification, will be described with
bone.
In the costal cartilages the cells and nuclei are large, and the matrix has a
tendency to fibrous striation, especially in old age. These cartilages also are
very prone to ossify. In the thickest parts of the costal cartilages a few large
vascular channels may be detected. Tliis appears at first sight an exception to
the statement that cartilage is a non-vascular tissue, but it is not so really, for
the vessels give no branches to the cartilage- substance itself, and the channels
may rather be looked upon as involutions of the perichondrium. The ensiform
cartilage may be regarded as one of the costal cartilages, and the cartilages of
the nose and of the larynx and trachea resemble them in microscopical charac-
ters, except the epiglottis and cornicula laryngis, which arc of the reticular
variety.
The hyaline cartilages, especially in adult and advanced life, arc prone to
^^
,;-
Costal CAitilai^o ftom i rmn se\entj six years of
age, showiii!? the development of fibious btiuctuie
in the matrix. In several portions of the speci-
men, two or three generations of cells are seen in-
closed in a parent cell-wall. (High power.)
CARTILAGE. 45
calcify — that is to saj, to liave tlieir matrix permeated by tlie salts of lime,
witliout any appearance of true bone. This process of calcification occurs also,
and still more frequently according to EoUett, in such cartilages as those of the
trachea, which are prone afterwards to conversion into true bone. It is on the
confines of true ossification that this calcareous change or degeneration is most
liable to occur, so that it is rare to find true bone and true cartilage in juxta-
position at the confines of the normal ossification, as, for instance, at the joint
ends, at the ends of the ribs, in the symphysis pubis and intervertebral carti-
lages.
Fihro-cartilage consists of a mixture of white fibrous and cartilaginous tissues
in various proportions ; it is to the first of these two constituents that its flexi-
bility and toughness are chiefly owing, and to the latter its elasticity. The
Fiff. 16.
S|p).-^
White fibrous cartilage from the semilunar disk of the patella joint of an ox. (Blagnified 100 times.)
fibro-cartilages admit of arrangement into four groups — interarticular, connect-
ing, circu.mferential, and stratiform.
The interarticular fibro-cartilages {pienisci) are flattened fibro-cartilaginoiis
plates, of a round, oval, or sickle-like form, interposed between the articular
cartilages of certain joints. They are free on both surfaces, thinner towards
their centre than at their circumference, and held in position by their extremi-
ties being connected to the surrounding ligaments. The synovial membrane of
the joint is prolonged over them a short distance from their attached margin.
They are found in the temporo-maxillary, sterno-clavicular, acromio-clavicular,
wrist, and knee joints. These cartilages are usually found in those joints which
are most exposed to violent concussions, and subject to frequent movement.
Their use is — to maintain the apposition of the opposed surfaces in their various
motions ; to increase the depth of the articular surface, and give ease to the
gliding movement ; to moderate the eflfects of great pressure, and deaden the
intensity of the shocks to which the parts may be submitted. Yirchow describes
in the semilunar cartilages of the knee a system of anastomosing tubes, formed
by cells which communicate with each other, and by means of which the nutri-
tious fluids are conveyed into the interior of the mass. The semilunar disks,
according to this author, are wrongly denominated cartilages, since they yield
no chondrine on boiling ; and he appears to regard them as a modification of
tendinous structure, which, however, agrees with the cartilages in the imjiortant
particular of being non- vascular. (See Yirchow's "Cellular Pathology," by
Chance, pp. 87-89.)
The connecting fihro-cartilages are interposed between the bony surfaces of
those joints which admit of only slight mobility, as between the bodies of the
vertebrse and the pubic symphyses ; they form disks, which adhere closely to
both of the opposed bones, and are composed of concentric rings of fibrous tissue,
46
GENERAL ANATOMY.
with cartilaginous laminas interposed, the former tissue predominating towards
the circumference, the latter towards the centre.
The circuinferential fihro-cartilages consist of a rim of fibro- cartilage, which
surrounds the margin of some of the articular cavities, as the cotyloid cavity
of the hip, and the glenoid cavity of the shoulder ; they serve to deepen the
articular surface and to protect the edges of the bone.
The stratiforin fihro-cartilages are those which form a thin layer in the osseous
grooves, through which the tendons of certain muscles glide.
Fiff. 17.
Yellow cartilage, ear of horse. (High power )
The yelloio or reticular cartilages found in the human body are the epiglottis,
cornicula laryngis, and the cartilaginous parts of the ear (auricle and Eustachian
tube). In this variety the cartilage-cells lie in the meshes of a network of yellow
elastic fibres, with a double outline, branching and anastomosing in all directions.
The fibres resemble those of the yellow elastic fibrous tissue, both in appearance
and in being unaffected by acetic acid, and according to Rollett their continuity
with the elastic fibres of the neighboring cellular tissue admits of being demon-
strated.
The distinguishing feature of cartilage as to its chemical composition is that
it yields on boiling a substance called chondrine^ very similar to gelatine, but
differing from it in not being precipitated by tannin.
BONE.
Structure and Physical Properties of Bone. — Bone is one of the hardest struc-
tures of the animal body ; it possesses also a certain degree of toughness and
elasticity. Its color, in a fresh state, is of a pinkish white externally, and deep
red within. On examining a section of any bone, it is seen to be composed of
two kinds of tissue, one of which is dense and compact in texture, like ivory :
the other consisting of slender fibres and lamellse, which join to form a reticular
structure ; this, from its resemblance to lattice-work, is called cancellous. The
compact tissue is always placed on the exterior of a bone ; the cancellous tissue
is always internal. The relative quantity of these two kinds of tissue varies in
different bones, and in different parts of the same bone, as strength or lightness
is requisite. Close examination of the compact tissue shows it to be extremely
porous, so that the difference in structure between it and the cancellous tissue
depends merely upon the different amount of solid matter, and the size and
number of the spaces in each ; the cavities being small in the compact tissue,
BONE. 47
and the solid matter between them abundant; whilst in the cancellous tissue
the spaces are large, and the solid matter in smaller quantity.
Bone during life is permeated by vessels, and is inclosed in a fibrous mem-
brane, the periosteum, by means of which most of these vessels reach the hard
tissue. If the periosteum be stripped from the surface of the living bone, small
bleeding points are seen, which mark the entrance of the periosteal vessels ; and
on section during life every part of the bone will be seen to exude blood, from
the minute vessels 'which ramify in the Haversian canals. The interior of the
bones of the limbs presents a cylindrical cavity filled with marrow, and lined
by a highly vascular areolar membrane, the medullary membrane or internal
periosteum. The larger Haversian canals are also filled with marrow.
The periosteum adheres to the surface of the bones in nearly every part,
excepting at their cartilaginous extremities. Where strong tendons or ligaments
are attached to the bone, the periosteum is incorporated with them. It consists
of two layers closely united together ; the outer one formed chiefly of connective
tissue, containing occasionally a few fat-cells ; the inner one, of elastic fibres of
the finer kind, forming dense membranous networks, which can be again sepa-
rated into several layers (Kolliker). In young bones the periosteum is thick,
and very vascular, and is intimately connected at either end of the 'bone with
the epiphysial cartilage, but less closely with the shaft, from which it is separated
by a layer of soft blastema, in which ossification .proceeds on the exterior of the
young bone. Later in life the periosteum is thinner, less vascular, and more
closely connected with the adjacent bone, this adhesion growing stronger as age
advances. The periosteum serves as a nidus for the ramification of the vessels
previous to their distribution in the bone ; hence the liability of bone to exfolia-
tion or necrosis, when, from injury, it is denuded of this membrane.
The marrow differs in composition at different periods of life, and in different
bones. In young bones, it is a transparent reddish fluid, of tenacious consistence,
free from fat; and contains numerous minute roundish cells with many nuclei.
In the shafts of adult long bones, the marrow is of a yellow color, and contains,
in 100 parts, 96 fat, 1 areolar tissue and vessels, and 3 of fluid with extractive
matters ; whilst, in the flat and short bones, in the articular ends of the long
bones, in the bodies of the vertebra3, in the base of the cranium, and in the
sternum and ribs, it is of a red color, and contains, in 100 parts, 75 water and
25 solid matter, consisting of albumen, fibrin, extractive matter, salts, and a
mere trace of fat. The red marrow is said by Kolliker to consist of a small
quantity of areolar tissue and numerous medullary cells, and fat-cells with a
large quantity of fluid.
Vessels of Bone. — -The bloodvessels of bone are very numerous. Those of the
compact tissue are derived from a close and dense network of vessels, ramifying
in the periosteum. From this membrane, vessels pass into the minute orifices
in the compact tissue, running through the canals which traverse its substance.
The cancellous tissue is supplied in a similar way, but by a less numerous set
of larger vessels, which, perforating the outer compact tissue, are distributed to
.the cavities of the spongy portion of the bone. In the long bones, numerous
apertures may be seen at the ends near the articular surfaces, some of which
give passage to the arteries referred to ; but the most numerous and largest
apertures are for the veins of the cancellous tissue which run separately from
the arteries. The medullary canal in the shafts of the long bones is supplied
by one large artery (or sometimes more), which enters the bone at the nutrient
foramen (situated in most cases near the centre of the shaft), and perforates
obliquely the compact substance. This medullary or nutrient artery, usually
accompanied by one or two veins, sends branches upwards and downwards, to
supply the medullary membrane, which lines the central cavity and the adjoin-
ing canals. The ramifications of this vessel anastomose with the arteries both
of the cancellous and compact tissues. In most of the flat, and in many of the
short spongy bones, one or more large apertures are observed, which transmit,
48 GENERAL ANATOMY.
to tlie central parts of tlie bone, vessels corresponding to tlie medullary arteries
and veins.
The veins emerge from tlie long bones in tliree places (Kolliker). 1. By a
large vein which accompanies the nutrient artery; 2. By numerous large and
small veins at the articular extremities ; 3. By many small veins which arise
in the compact substance. In the flat cranial bones the veins are large, very
numerous, and run in tortuous canals in the diploic tissue, the sides of the canals
being formed of a thin lamella of bone, perforated here and' there for the pass-
age of branches from the adjacent cancelli. The veins thus inclosed and sup-
ported by the osseous structures have exceedingly thin coats ; and when the
bony structure is divided, they remain patulous, and do not contract in the canals
in which they are contained. Hence the constant occurrence of purulent absorp-
tion after amputation, in those cases where the stump becomes inflamed, and
the cancellous tissue is infiltrated and bathed in pus.
Lymphatic vessels have been traced, by Cruikshank, into the substance of
bone, but Kolliker doubts their existence. Nerves are distributed freely to the
periosteum, and accompany the nutrient arteries into the interior of the bone.
They are said, by Kolliker, to be most numerous in the articular extremities of
the long bones, in the vertebrae, and the larger flat bones.
Minute Anatomy. — The intimate structure of bone, which in all essential par-
ticulars is identical in the compact and cancellous tissue, is most easily studied
in a transverse section from the compact wall of one of the long bones after
Fig 18. Fig. 19.
(
«?'>-
i;j.
e^J^^hi^^ilM^^-^^^ af^
%
From ,a transverse section of thfi cli.aijliysis of the
liumerus, magnified 350 times, a, Haversian canals, b, Section parallel to the surface from the shaft
lacunae, with their cnnaliculi in the lamelloc of these of the femur, magnified 100 times, a, Haversian
canals, c, lacuntc of the interstitial lamelloe. <f, others canals. 6, lacunoc seen from the side, c, otliera
at the surface of the Hnversian systems, with cannliculi seen from the surface in lamellae which are cut
f^oing off from one side. horizontally.
maceration, such as is shown in Fig. If^. The large round spaces scon in the
figure arc the Tfavorsinn canals.^ and in tlicse canals the larger vessels of the bone
ramifv. The smaller TIavcrsian canals contain arteries, the larger, veins, a single
vessel being lodged in each canal. The fine lines leading out of (or into) these
BONE. 49
canals, are called, canaliculi^ and the irregular dark spaces, whicli may be noticed
to have a general circular arrangement round the Haversian canals, are called
the lacunse. The canaliculi which originate in one lacuna most frequently run
into a neighboring lacuna, or else into a neighboring Haversian canal ; some of
them, however, anastomose with others in their neighborhood, and a few appear
to terminate in blind extremities, or to bend backwards. The concentric rings
of lacuna round each Haversian canal are called lamellse. The irregular inter-
vals which would be left by the juxtaposition of these lamella, are seen in the
■figure to be filled up by lacuna and canaliculi, which communicate with the
systems composing the adjacent lamellse. Besides the lamellse which are con-
centric to the Haversian systems there are other lamellae, most perceptible on
the surface of the bone, which are concentric to the medullary cavity. These
are most distinct in the adult bone. These lamellse, which are laid down around
the axis of the bone itself, are called by some authors the primary or funda-
mental lamellse^ to distinguish them from those laid down around the axis of the
Haversian canals, the secondary or special lamellpe. The interstitial lamellse
found between the Haversian systems can sometimes be recognized as belonging
to the primary lamellse ; but this is not always the case. The interspaces be-
tvv^een the lacunae and canaliculi are filled with a granular homogeneous solid
m^aterial, the ultimate mineral base of the bone.
If a longitudinal section be taken, as in Fig. 19, the appearances are identical.
The appearance of concentric rings is replaced by that of lamella or rows of
lacunas parallel to the course of the Haversian canals ; and these canals appear
like half- tubes instead of circular spaces. The tubes are seen to branch and
communicate, so that each separate Haversian canal runs only a short distance.
In other respects the structiire has much the same appearance as in transverse
sections.
In sections of thin plates of bone (as in the walls of the cells which form the
cancellous tissue), the Haversian canals are absent, whenever the thickness of
bone is not too great to allow of its nutritious juices being absorbed from the
fibrous membrane coating either side by means of the lacunae and canaliculi
only ; but when the thickness becomes at all considerable. Haversian systems
begin to appear. Thus the spaces of the cancellous tissue (medullary spaces) have
the same function there that the Haversian canals have in the more compact tissue.
In the long bones, by maceration in dilute mineral acid, it may easily be
shown that besides these microscopic lamellae surrounding each Haversian
canal, the whole bone is composed of distinct laminse, concentrically disposed
around the medullary tube. These laminae are crossed and pinned together, as
it were, by the fibres of bone running obliquely through them, which were first
described by Dr. Sharpey, and named by him perforating fibres. In the flat
bones parallel or superimposed plates can be demonstrated similarly held to-
gether by perforating fibres, which are more numerous than in the long bones.^
Besides the Haversian canals larger and irregular shaped spaces are found —
Haversian sp)aces — which are, as it were, a transition from the Haversian canals
to the medullary spaces of the cancellous tissue. It seems as if both the medul-
Isiry spaces and the Haversian spaces are formed by absorption, as we shall try
to explain in speaking of the development and growth of bone. These Haver-
sian spaces are found chiefly in growing bones ; but they occur also, though in
less number, in the adult bones. They have irregular jagged outlines, and the
adjoining systems of lacunae and canaliculi are seen to be eaten away by them.
When the microscopic structure of bone was first demonstrated, it was
beheved that the lacunse were solid cells, and their canaliculi solid processes
from those cells. Subsequently, when it was seen that the Haversian canals
are channels which lodge the vessels of the part, and the canaliculi and lacunae
spaces by which the plasma of the blood, or the blood itself circulates through
' Sharpey, in Quaiii's Anatomy, 7th edit., p. xcv.
50
GENERAL ANATOMY.
tile tissue, it was tauglit tliat the lacunge were hollow spaces filled during life
with that fluid, and only lined (if lined at all) by a delicate membrane. But
this view appears also to be delusive. Examination of the structure of the
bone, when recent, has led Virchow to believe that the so-called lacunae are
really filled up during life with a nucleated cell, the processes from which pass
down the canaliculi. It is by means of these cells that the fluids necessary for
nutrition are brought into contact with the ultimate tissue of the bone.
The animal part of a bone may be obtained by immersing the bone for a con-
siderable time in dilute mineral acid, after which process the bone comes out
exactly the same size and shape as before.
Fig. 20. but perfectly flexible — so that a long bone
^.fc::^ (one of the ribs is the usual example) can
^^Jl^^''3'=^»-w-'^'-v^ ^,^ ' '" X easily be tied in a knot. If now a trans-
^•^^^rC'm^ "'^ '- *^ A verse section be made, the same general
t^i' \^M^^^^^' - / arrangement of the Haversian canals,
^V V'-S^^^^^^^'vTw" _ _ ^- A lamellte, lacunae, and canaliculi is seen,
Hi' V \ though not so plainly as in the macerated
Wk y>.j // j^^LU 1 ,j ,^ ' — - * If specimen. If the individual lamellas are
. \2,r2^'7///''i%f -V -^?' V }^i J L 1 1 / examined, they are found to be composed of
^•^^^ •^I^p^^•^*>*''s*■iQii'-i^^^ h bres, most ot which are nearly parallel ;
Section of bone after the removal of the earthy ^ut which interlace together, and auasto-
matter by the action of acids. mosc or commuuicate with the fibres of
the neighboring lamellae. The organic or
animal constituent of a bone is only incompletely removed by maceration, leav-
ing the bone for an indefinite period perfectly tough and coherent ; but after
being long kept in a warm dry atmosphere, or by incineration in a furnace, the
animal part may be entirely removed, and then the earthy constituent will
retain the form of the original bone, but on the slightest force it will crumble
down. The animal base is often called cartilage, but differs from it in the fol-
lowing respects : viz., that it is softer and more flexible, and when boiled with a
high pressure is almost entirely resolved into gelatine. Cartilage does, however,
form the animal basis of bone in certain parts of the skeleton. Thus, according
to Tomes and De Morgan, it occurs in the petrous part of the temporal bone,
and, according to Dr. Sharpey, on the articular ends of adult bones, lying
underneath the natural cartilage of the joint.
Chemical Analysis. The organic constituent of bone forms about one-third,
or 33.3 per cent. ; the inorganic matter, two-thirds, or 66.7 per cent. ; as is seen
in the subjoined analysis by Berzelius : —
Organic Matter, Gelatin and bloodvessels 33.30
f Phosphate of lime ........ 51.04
Inorganic \ Carbonate of lime ........ 11.30
or -] Fluoride of calcium .....'.. 2.00
Earthy Matter, \ Phosphate of magnesia ....... 1-16
[Soda and chloride of sodium 1.20
100.00
Some chemists add to this about 1 per cent, of fat.
The relative proportions of the two constituents of bone are found to difl'er
m different hones of the sheleton, as shown by Dr. Owen Rees. Thus, the bones
of the head, and the long bones of the extremities, contain more earthy matter
than those of the trunk; and those of the upper extremity somewhat more than
the corresponding bones of the lower extremity. The humerus contains more
earthy matter than the bones of the forearm , and the femur more than the
tibia and fibula. The vcrtcbrre, ribs, and clavicle, contain nearly the same pro-
j)ortion of earthy matter. The metacarpal and metatarsal bones contain about
tlic same proportion as those of the trunk.
Much dificrence exists in the analyses given by chemists as to the proportion
between the two constituents of bone at different periods of life. According to
BONE. 51
Sclireger, and others, there is a considerable increase in the earthy constituents
of the bones with advancing years. Dr. Rees states, that this is especially
marked in the long bones, and the bones of the head, which, in the foetus, do
not contain the excess of earthy matter found in those of the adult. But the
bones of the trunk in the foetus, according to this analyst, contain as much
earthy matter as those of the adult. On the other hand, the analyses of Stark
and Yon Bibra show, that the proportions of animal and earthy matter are
almost precisely the same at different periods of life. According to the analyses
of Von Bibra, Valentin, and Dr. Rees, the compact substance contains more
earthy matter than the cancellous. The comparative analysis of the same bones
in both sexes shows no essential difference between them.
There are facts of some practical interest, bearing upon the difference which
seems to exist in the amount of the two constituents of bone at different periods
of life. Thus, in the child, where the animal matter predominates, it is not
uncommon to find, after an injury to the bones, that they become bent, or only
partially broken, from the large amount of flexible animal matter which they
contain. Again, in aged people, where the bones contain a large proportion of
earthy matter, the animal matter at the same time being deficient in quantity
and quality, the bones are more brittle, their elasticity is destroyed ; and hence
fracture takes place more readily. Some of the diseases, also, to which bones
are liable, mainly depend on the disproportion between the two constituents of
bone. Thus, in the disease called rickets, so common in the children of scro-
fulous parents, the bones become bent and curved, either from the superincum-
bent weight of the body, or under the action of certain muscles. This depends
upon some defect of nutrition, by which bone becomes deprived of its normal
proportion of earthy matter, whilst the animal matter is of unhealthy quality.
In the vertebrae of a rickety subject, Dr. Bostock found in 100 parts 79.75
animal, and 20.25 earthy matter.
Development of Bone. In the foetal skeleton, some bones, such as the long
bones of the limbs, are cartilaginous ; others, as the cranial bones, are mem-
branous.^ Hence two kinds of ossification are described : the intra-cartilaginous
and the intra-memhranous ; and to these a third is sometimes added, the sub-
periosteal^ which is a variety of the second.
In the intra-cartilaginous ossification two chief primary changes occur in the
cartilage simultaneously — viz., that the cartilage becomes vascular, and that it
calcifies. The vessels shoot into the cartilage from the neighboring periosteum,
constituting what is called " the centre of ossification," which is seen in injected
specimens so strongly contrasted with the neighboring non-vascular cartilage.
The first step in the calcification of the cartilage is, that the cartilage-cells
increase rapidly in number, and arrange themselves in rows, with the long axis
of the cell transverse to that of the future bone (Fig. 21, a). If calcification has
already advanced somewhat further, there is seen, lower down in the section, a
layer of large clear cells with granular contents, which are also arranged in
somewhat parallel rows, separated still by a transparent cartilaginous matrix ;
while still deeper down the matrix has calcified, so that, if a transverse section
be made here, rings of dark granular substance will be seen inclosing the large
round cells (Rollett). As the section is taken deeper and deeper into the ossi-'
fying part, the calcified rings, or primary areolae^ are seen to inclose numerous
smaller granular masses (" primitive or foetal marrow"), which have been sup-
posed to be developed out of the large clear cells shown above them in the
figure, and thus to be the descendants of the cartilage-cell. But the view
which is now more generally adopted is that the cartilage-cells, after becoming
* The bones which are developed entirely in membrane are the occipital, as far as it enters into
the formation of the vault of the skull, the parietal and frontal bones, the squamous portion of
the temporal with the tympanic ring, the Wormian bones, the nasal, lachrymal, malar, palate,
upper and lower maxillary, and vomer ; also, apparently, the internal pterygoid plate and the
sphenoidal turbinated bones.
62
GENERAL ANATOMY
developed into these round clear bodies, are dissolved, and slied their granular
contents to form the calcareous matrix, while the cells which line the primary
areolae, and from which the future bone is developed, and which are on that
account called " osteoblasts," are furnished by the bloodvessels which are to be
Fio-. 21.
Longitudinal section throu£;h the ossifying portion of a long bone in tiie human embryo, a, cartilaginous
region. 6, region of the rounil clear cells, g, region of the dark granular masses.
found in those spaces. As these bloodvessels advance into the areola?, the latter
break down, giving rise to the primary medullary canals, which are the rudi-
ments of the Haversian canals. (Fig. 22.) The osteoblasts are believed to be
corpuscles emigrating out of these vessels, and are described by Frey as being
differentiated from a mass of lymphoid cells, some of which become developed
into connective-tissue fibres, which traverse the bone ; others preserve the old
lymphoid form, and may be recognized in that form during the whole of life in
the red marrow ; while others possibly form the fat-cells of the yellow marrow.
The osteoblasts line the wall of the medullary space like an epithelium. They
secrete the bony substance which separates the lacunae from each other. This
appears first as a homogeneous opalescent material, in which bone salts are
afterwards laid down, while the cells themselves remain persistent as the bone-
corpuscles. (Fig. 28.) As fresh laminae of this osseous formation arc laid down,
fresh layers of osteoblasts line the interior of the cavity, till the process results in
the completion of the Haversian canal and its system of lamellae. The precise
mode of origin of the canaliculi from the bone-corpuscles has not been ascertained.
Thus far, then, we have followed the steps of a process by which a solid bony
mass is produced, having vessels running into it from the periosteum, Haversian
canals in wiiich those vessels run, medullary spaces filled with foetal marrow.
BONE.
53
lacunjB with, their contained bone -cells, and canaliculi growing out of those
lacunte.
This process of ossification, however, is not the origin of the whole of the
skeleton, for even in those bones in which the ossification proceeds in a great
Fiff. 23.
Transverse section from the femur of a human embryo
about eleven weeks old. a, a medullary sinus cut trans-
versely, and b, another longitudinally, c, osteoblasts, d,
newly formed osseous substance of a lighter color, e, that of
greater age. /, lacunae with their cells, g, a cell still united
to an osteoblast.
Vertical section from the edge of the
ossifying portion of the diaphysis of a
metatarsal bone from a fcetal calf, after
Miiller. a, ground-mass of the carti-
lage; 6, of the bone, c, newly formed
bone-cells in profile, more or less em-
bedded in intercellular substance, d,
medullary canal in process of formation,
with vessels and medullary cells. e,f,
bone-cells on their broad aspect, g,
cartilage capsules arranged in rows,
and partlj' with shrunken cell-bodies.
measure from a single centre situated in the cartilaginous diaphjsis a consider-
able part of the original bone is formed by intra-membranous ossification beneath
the perichondrium or periosteum. Ktilliker (following H. Miiller, and referring to
an observation of Howship to the same effect made so long ago as 1819) describes
the first rudiment of a long bone as having the form of a tube, surrounding the
primordial cartilage ; thus showing that the intra-membranous ossification of the
outer part of the bone from the periosteum even precedes the intra- cartilaginous
development of its interior from the "ossific centre." Also, a great part of the
increase in girth of the bone takes place by bony deposit from the deeper layer
of the periosteum. This process is now acknowledged to belong to the intra-
membranous form of ossification. Thus even in long bones only a portion of
their tissue is formed by intra-cartilaginous ossification.
54
GENERAL ANATOMY.
Tlie sliaft of tlie bone is at first solid, but a tube is gradually hollowed out in
it by absorption around the vessels passing into it, which becomes the medullary
canal ; and as more and more bone is deposited from the periosteum, so more
and more is removed from around the medullary membrane, until at length the
bone has attained the shape and size which it is destined to retain during adult
life. As the ossification of the cartilaginous diaphysis extends towards the
articular ends, it carries with it, as it were, a layer of cartilage, or the cartilage
grows as it ossifies. During this period of growth the articular end, or epiphysis,
remains for some time entirely cartilaginous, then a bony centre appears in it,
and it commences the same process of intra-cartilaginous ossification ; but this
process never extends to any very great distance. The epiphyses remain sepa-
rated from the shaft by a narrow cartilaginous layer for a definite time. This
layer ultimately ossifies, the distinction between shaft and epiphysis is obliterated,
and the bone has assumed its completed form and shape. The same remarks also
apply to the processes of bone which are separately ossified, and called a'po'physes.
The intra-cartilaginous ossification, and the growth by means of epiphyses,
are usually described from the long bones ; but almost all the bones of the body
are primarily laid down in cartilage (see note, p. 51) ; and a great many of the
flat and short bones grow by means of epiphyses, as will be seen in the detailed
description of each, given in the body of the work.
The medullary spaces which characterize the cancellous tissue are produced
by the absorption of the original fcetal bone in the same way as the medullary
tube is formed, and the same is the case with the Haversian spaces above referred
to as a sort of intermediate step between the Haversian canals and the medullary
spaces. In the medullary spaces so formed the large "giant-cells" are found,
which have been long described as a constituent of the foetal marrow, and to
which lately the power has been ascribed of dissolving or absorbing the bone,
so that Kolliker has named them "osteoclasts." This function, however, is
denied by some of the best authorities.^ They vary in shape and size, and are
known by containing a large number of clear nuclei, sometimes as many as
twenty. The occurrence of similar cells in some tumors of bone has led to their
being denominated "myeloid." The distinction between the cancellous and
compact tissue appears to depend essentially upon the extent to which this
process of absorption has been carried, and we may perhaps remind the reader
that in morbid states of the bone inflammatory absorption effects exactly the same
change, and converts portions of bone naturally compact into cancellous tissue.
The intra-membranous ossification is that by which the bones of the vertex
of the skull are entirely formed. In the
Fig. 24. bones which are so developed no cartila-
ginous mould j^recedes the appearance of
-/?^:^3M'S?5^s_ /^.-^r^ -0^^^^^ the bone tissue. The process, though
pointed out originally by Dr. Nesbitt in
the year 1736, was first accurately de-
scribed by Dr. Sharpey; and it does not
appear that subsequent observers have
been able to add anything essential to his
description. This is, substantially, as fol-
lows: In the membrane which occupies
tlie place of the future bone a little network
of bony spicnlye is first noticed, radiating
h X . '" from the point of ossification. When these
Osteoblasts from the parietal bono of a human rays of growing bonc are examined by the
embryo thirteen weeks old (after Gegcnbaiior). UlicroSCOpe, tllCre is found a UCtWOrk of fine
a bony Bopta with the «;"« of the lacuna.. i>. doar fibrcs (ostcogcnic fibres), wliich bccomc
layers of osteoblasts, c, the latter In transirinn , . ^ i p \ • c • i
to bono-corpuflcies. (uirk and grauuhir from calcification, ana
' Froy sjiys : "I liavc not the fuiiitcst belief in tlieir possess iiif;^ lliis property."
BONE. 55
as tliey calcify tliey are found to inclose in their interior large granular corpus-
cles or "osteoblasts." These corpuscles at first lie upon the osteogenic fibres, so
that the corpuscles must be removed by brushing the specimen with a hair-
pencil in order to render the fibres clear ; but they gradually sink into areolae
developed among the fibres. The areolse appear to be the rudiments of the
lacunae, the passages between the fibres form the canaliculi, and the osteo-
blasts are the rudiments of the bone-cells. As the tissue increases in thickness
vessels shoot into it, grooving for themselves spaces or channels, which become
the Haversian canals. Thus the intra-membranous and intra-cartilaginous pro-
cesses of ossification are similar in their more essential features.
The subperiosteal is a form of the intra-membranous process of ossification.
The period of ossification is different in different bones. The order of succes-
sion may be thus arranged (Kolliker) : —
In the second month, first, in the clavicle and lower jaw (fifth to seventh
week); then, in the vertebrje, humerus, femur, the ribs, and the cartilaginous
portion of the occipital bone.
At the end of the second, and commencement of the third month, the frontal
bone, the scapula, the bones of the forearm and leg, and upper jaw make their
appearance.
In the third month, the remaining cranial bones, with few exceptions, the
metatarsus, the metacarpus, and the phalanges, begin to ossify.
In the fourth month, the iliac bones, and the ossicula auditus.
In the fourth or fifth month, the ethmoid, sternum, os pubis, and ischium.
From the sixth to the seventh month, the calcaneum and astragalus.
In the eighth month, the hyoid bone.
At birth, the epiphyses of all the cylindrical bones, with the exception of the
lower epiphysis of the femur, and occasionally the upper epiphysis of the tibia ;
all the bones of the carpus ; the five smaller ones of the tarsus ; the patella ; the
sesamoid bones ; and the coccyx,^ are still unossified.
From the time of birth to the fourth year, osseous nuclei make their apjjear-
ance also in these parts.
At twelve years, in the pisiform bone.
The number of ossific centres is different in different bones. In most of the
short bones, ossification commences by a single point in the centre, and proceeds
towards the circumference. In the long bones, there is a central point of
ossification for the shaft or diaphysis ; and one or more for each extremitj^, the
epiphyses. That for the shaft is first to appear; those for the extremities appear
later. The union of the epiphyses with the shaft takes place in the inverse order
to that in which their ossification began ; for although ossification commences
latest in those epiphyses towards which the nutrient artery in the several bones
is directed, they become joined to the diaphyses sooner than the epiphyses at
the opposite extremity, with the exception of the fibula, the lower end of which
commences to ossify at an earlier period than the upper end, but, nevertheless,
is joined to the shaft earliest.
The order in which the epiphyses become united to the shaft, appears to be
regulated by the direction of the nutrient artery of the bone. Thus, the nutrient
arteries of the bones of the arm and forearm are directed towards the elbow,
and the epiphyses of the bone forming this joint become united to the shaft
before those at the opposite extremity. In the lower extremities, on the con-
trary, the nutrient arteries pass in a direction from the knee ; that is, upwards
in the femur, downwards in the tibia and fibula ; and in them it is observed,
that the upper epiphysis of the femur, and the lower epiphyses of the tibia and
fibula, become first united to the shaft.
Where there is only one epiphysis, the medullary artery is directed towards
that end of the bone where there is no additional centre: as, towards the acro-
' On the development of the coccyx, vide Anatomy of the Coccyx.
56
GENERAL ANATOMY.
mial end in the clavicle; towards tlie distal end of the metacarpal bone of the
thumb and great toe ; and towards the proximal end of the other metacarpal
and metatarsal bones.
Besides these epiphyses for the articular ends, there are others (more com-
monly called ajDophyses) for projecting parts, or processes, which are formed
separately from the bulk of the bone. For an account of these, the reader must
be referred to the descriptions of the individual bones in the sequ.el.
A knowledge of the exact jDcriods when the epiphyses become joined to the
shaft is often of great importance in medico-legal inquiries. It also aids the
surgeon in the diagnosis of many of the injuries to which the joints are liable ;
for it not unfrequently happens, that on the application of severe force to a joint,
the epiphyses become separated from the shaft, and such injuries may be mis-
taken for fracture or dislocation.
MUSCULAE TISSUE.
Fi^. 25.
a
The Muscles are formed of bundles of reddish fibres, endowed with the pro-
perty of contractility. Two kinds of muscular tissue are found in the animal
body, viz., that of voluntary or animal life, and that
of involuntary or organic life.
The muscles of animal life {striped muscles) are
capable of being put in action and controlled by the
will. They are composed of bu.ndles of fibres in-
closed in a delicate web of areolar tissue, called in
the figure the "perimysium." Each bundle consists
of numerous smaller bundles inclosed in a similar
fibro-areolar covering, and these again of primitive
fasciculi. Fat cells are sometimes intermixed with
this connective tissue.
The fibres are of no great length — not extending,
it is said, further than an inch and a half. They
end either by blending with the tendons or aponeu-
rosis, or else by becoming drawn out into a tapering
extremity which is connected to the neighboring
fibre by means of the sarcolemma. The precise
mode in which the muscular fibre joins the tendon
has been variously described by different observers.
It may, perhaps, be sufficient here to say that the
sarcolemma, or membranous investment of the muscular fibre, appears to be-
come blended with the tissues of the tendon, and that the muscular fibre appears
to be prolonged more or less into the tendon, so that the latter forms a kind of
sheath around the fibre for a longer or shorter distance. When muscular fibres
are attached to the skin or mucous membranes, their fibres are described by
riyde Salter as becoming continuous with those of the areolar tissue.
The primitive fasciculi consists of a number of filaments, inclosed in a tubular
f.heath of transparent elastic, and apparently homogeneous membrane, named
by Bowman the "Sarcolemma." On the internal surface of the sarcolemma, in
mammialia, and also in the substance of the fibrillae in lower animals, elongated
nuclei are seen (see Figs, 42, 43), and in connection with these nuclei a row of
granules, apparently fatty, is sometimes observed. The primitive fasciculi are
cylindriforin or prismatic. Tlieir breadth varies in man from jj^^ to ^^^ of an
inch, the average of the majority being about -^Ij-,] their length is not always
in proportion to the length of the muscle, but depends on the arrangement of
the tendons. This form of muscular fibre is especially characterized by being
apparently marked with very fine, dark lines or stritv, which pass transversely
round the fibre, in curved or wavy parallel directions from xuodti ^'^ T-inno of an
Transverse section from the
sterno-mastoid in man (50 times
magnified), a, external perimysium.
b internal perimysium, c, primitive
and secondary fasciculi.
MUSCULAR TISSUE.
57
inch apart. Otiier strife pass longitudinally over tlie fibres, indicating tlie direc-
tion of the primitive fibrils of which the primitive fasciculus is composed. They
are less distinct than the former.
Fiff. 26.
Fig. 27.
Two human muscular fibres
(magnified 350 times). In the
one, the bundle of fibrillse
(6) is torn, and the sarco-
lemma (a) is seen as an empty
tube.
Fragments of striped elementary fibres, showing a cleavage in opposite
directions (magnified 300 diameters), a, Longitudinal cleavage. The
longitudinal and transverse lines are both seen.- Some longitudinal lines
are darker and wider than the rest, and are not continuous from end to
end. This results from partial separation of the fibrillse. c, Fibrillse sepa-
rated from one another by violence at the broken end of the fibre, and
marked by transverse lines equal in width to those on the fibre, c' c", re-
present two appearances commonly presented by the separated single
fibrillce more highly magnified. At c' the borders and transverse lines are
all perfectly rectilinear, and the included spaces perfectly rectangular. At
e" the borders are scalloped and the spaces bead-like. When most distinct
and definite, the flbrilla presents the former of those appearances, b,
Transverse cleavage. The longitudinal lines are scarcely visible, a, In-
complete fracture following the opposite surfaces of a disk, which stretches
across the interval, and retains the two fragments in connection. The
edge and surfaces of this disk are seen to be minutely granular, the gran-
ules corresponding in size to the thickness of the disk, and to the distance
between the faint longitudinal lines, b, Another disk nearly detached.
b', Detached disk (more highly magnified), showing the sarcous elements.
The primitive fibrils constitute the proper contractile tissue of the muscle.
Each fibril is cylindriform, somewhat flattened, about Yg',oo of an inch in
thickness, and marked by transverse strise placed at the same distance from each
other as the striee on the surface of the fasciculus. Each fibril apparently con-
sists of a single row of minute particles (named "sarcous elements" by Bowman),
connected together like a string of beads. Closer examination, however, shows
that the elementary particles are little masses of pellucid substance, having a
rectangular outline, and appearing dark in the centre. These appearances would
favor the suggestion that the elementary particles of which the fibrils are com-
posed are possibly nucleated cells, cohering in a linear series, the transverse
marks between them corresponding to their line of junction. Kolliker, how-
ever, considers "the sarcous elements as artificial products, occasioned by the
breaking up of the fibril at the parts where they are thinner."
On closer examination, the appearances become more complicated, and are
susceptible of various interpretations. Thus, if we apply a higher power of the
microscope, the transverse striation which in Figs. 26, 27 appears as a mere
alternation of dark and bright bands is resolved into the appearance shown in
Fig. 28, which shows a series of broad dark bands, separated by a bright band,
which is itself divided into two by a row of dark dots. This appearance Avas
first pointed out by Busk and Huxley. It is explained by Krause as depending
on some optical property of the investment of the separate sarcous elements.
Thus it is supposed that the sarcous elements have an opaque interior, and are
united to each other by a transparent envelope or cell-membrane, the sides of
which cohere so closely as only to show a single line, Avhile their ends are united
by some different material which breaks up the light, and causes a dark band
.58
GENERAL ANATOMY.
or row of dark dots in tlie centre of tlie transparent streak formed "by the colie-
sion of the two cell-membranes. Mr. Schafer describes the sarcous elements
Fig. 28.
Fig. 29.
^
A, portion of a medium-sized human muspnlar fibre, magnified nearly 800 diameters. B, separated bundles
of fibrils, equally magnified, a, a, larger, and &, 6, smaller collections; c, still smaller; d, d, the smallest
which oould be detached.
as formed by an aggregation of rod-like masses of protoplasm, having rounded
ends, and believes that the two bright bands and intervening row of black dots
are the result of the diffraction of the light around
these rounded ends, "just as a minute oil-globule in
water appears surrounded with a bright halo when
examined under the microscope." But the question
is as yet by no means definitely settled.
This form of muscular fibre composes the whole
of the voluntary muscles, all the muscles of the ear,
those of the larynx, pharynx, tongue, the upper
half of the oesophagus, the heart, and the walls of
the large veins at the point where the}^ o]3en into it.
The fibres of the heart, however, differ in several
particulars from those of other striped muscles.
They are smaller by about one-third, and their
transverse strite are by no means so distinct. Fat-
cells are also often found in them to a certain ex-
tent, even apart from any obvious disease of the
organ. They break up much more readily into
their smallest elements. There is also much less
(if any) connective tissue separating the bundles of
fibres ; and Kolliker has described and figured the
ultimate fibres as anastomosing with each other, a
fact previously noticed by Lecuwenhoeck. SchAveig-
gcr-Scidcl also describes and figures transverse
septa, which divide the fibres into separate nucleated portions (Fig. 29).
The unstriped muscle^ or muscle of orf/anic N/e, is found in the walls of the
hollow viscera, viz., the lower half of the oesophagus and the wliole of the re-
mainder of the gastro-intcstinal tube ; in the trachea and bronchi ; in the gall-
|=||^
Anastomosing muscular fibres of
the heart seen in a longitudinal sec-
tion. On the right the limits of the
sci)arate cells with their nuclei are
exhiliited somewhat diagrammati-
cally.
MUSCULAR TISSUE,
59
bladder and ductus communis choledoclius ; in the pelvis and calices of the kidney,
the ureters, bladder, and urethra ; in the female sexual organs, viz., the Fal-
lopian tubes, the uterus (enormously developed in pregnancy), the vagina, the
broad ligaments, and the erectile tissue of the clitoris ; in the male sexual organs,
viz., the dartos scroti, the vas deferens, and epididymis, the vesiculee seminales,
the prostate gland, and the corpora cavernosa ;^ in the ducts of certain glands,
as in "Wharton's duct ; in the capsule and trabeculse of the spleen ; in the mucous
membranes, forming the muscularis mucosse ; in the arteries, veins, and lym-
phatics ; in the iris ; and in the skin.
The fibres of inorganic muscle form flattened bands, which interlace in various
directions, and which when viewed without reagents appear nearly homogeneous,
though, if the organ from which the fibres are taken has been macerated pre-
viously for some time in dilute acid, the nuclei can be perceived. Even in fresh
fibres the nuclei are occasionally visible.
In many situations these fibres, by prolonged immersion in chromic or nitric
acid, can be resolved into the elementary contractile fibre-cells of which Kolliker
has shown that they really consist ; and in some parts, as in the arteries and in
the skin, such fibre -cells are found single. They are elongated, their length
about ten to fifteen times their breadth (.02'" to 0.4'" in length, .002'" to .003'"
in breadth, according to Kolliker), consisting of a spindle-shaped, homogeneous-
looking, fibre-cell, in which a rod-shaped nucleus is faintly visible. Acetic acid
dissolves out the granular contents of the cell, and brings the nucleus clearly
into view.
Fig. 30.
Fig. 31.
' Non-striated elementary fibres from the human
colon, a, treated with acetic acid, showing the
corpuscles. 6, fragment of a detached fibre, not
touched with acid.
Muscular fibre-cells from human arteries. 1, from the
popliteal artery; a, without, b, with acetic acid. 2,
from a branch of the anterior tibial; a, nuclei of the
fibres. (Magnified 350 times.)
The unstriped muscle, as a rule, is not under the influence of the will, nor is
the contraction rapid and involving the whole muscle, as is the case with the
muscles of animal life. The membranes which are composed of the unstriped
muscle slowly contract in a part of their extent, generally under the influence
of mechanical stimulus, as that of distension or of cold, and then the contracted
part slowly relaxes, while another portion of the membrane takes up the con-
Kcilliker describes muscular fibres also in the tunica vaginalis testis.
60 GENERAL ANATOMY.
traction, Tliis peculiarity of action is most strongly marked in tlie intestines,
constituting their vermicular motion.
In chemical composition, the muscular fibres of both forms consist mainly of
a substance {syntonin) nearly identical with the fibrine of the blood ; but, unlike
the latter, not dissolved by nitrate of potash. Muscle after death exhibits an
acid reaction ; but this appears to be due to post-mortem changes.
The capillaries of muscle are very abundant, and form a series of rectangular
areolae, the branches which run longitudinally between the muscular fibres,
being united at short intervals by transverse anastomosing branches.
Nerves are profusely distributed to the muscular tissue, more especially to the
voluntary muscles. The mode of their termination will be described on a sub-
sequent page.
The distribution and the mode of origin of the lymphatic vessels of muscle
have not yet been ascertained.
The muscles during life, and for some time after death, respond to the appro-
priate stimulus by contracting in the manner peculiar to the class to which
they belong. Thus, for some time after a limb has been amputated, its muscles
can be set in motion by scratching, pinching, or galvanizing them ; and even
after the irritability of the muscular tissue has been exhausted by the prolonged
suspension of the circulation, it can be at first temporarily restored by injecting
fresh arterial blood through it (Brown-Sequard). The time at which muscular
irritability ceases after death depends on tlie vitality of the subject ; thus it
ceases in birds, whose circulation and vital heat are of a very high degree,
sooner than in man and quadrupeds ; in these sooner than in fishes, etc. Dr.
Sharpey says that it lasts long in hybernating animals killed during their winter
sleep. It is also affected by the mode of dying, being extinguished instanta-
neously (as is asserted) in some cases of lightning-stroke, and much diminished
by certain gaseous poisons, particularly sulphuretted hydrogen.
As the muscles die they become stiff, and it is to this cause that the rigidity
so characteristic of recent death (" rigor mortis") is due. The ultimate cause
of the phenomenon is not well understood, beyond the obvious fact that it must
be due to the change from partial fluidity to a solid condition of the contents of
the sarcolemma. The periods of its occurrence and of its disappearance are
very variable, and the causes of those variations are of extreme interest and
importance, especially in medico-legal inquiries, but the subject is too compli-
cated to be adequately treated here. All that need be said in this place is that,
as might be expected, the rigor is stronger the more powerful and more healthy
the muscles are, and consequently is both more powerful and more lasting in
cases of sudden or violent death. It also sets in later in such cases, while in
emaciated and exhausted subjects it is more rapid and transient; as is also the
case, according to Hunter, in animals which have been hunted to death. In
some instances of violent death in persons of robust frame, the rigor mortis has
not entirely disappeared till the end of the first week after death. In rare cases
(as in some instances of death from lightning) the muscles are found rigid
immediately, and in other cases rigor commences in a few minutes, but usually
not till six or seven hours after death. The cessation of rigidity in the muscles
must be regarded as the commencement of putrefactive changes.
NERVOUS TISSUE.
The Nervous Tissue is composed chiefly of two different structures, the gray or
vesicular^ and the white or fibrous. It is in the former, as is generally supposed,
that nervous impressions and impulses originate, and by the latter that they are
conducted. Ilcnce the gray matter forms the essential constituent of all the
ganglionic centres, both those separated in the ganglia, and those aggregated in
the ccrebro-spinal axis; while the white matter is found in all the commissural
NERVOUS TISSUE.
Gl'
portions of the nerve centres, and in all tlie cerebro-spinal nerves. Besides tliese
two principal kinds of nervous matter, there is found a third structure— chiefly
in the sympathetic system — called the gelatinous nerve-tissue.
The nervous substance is again divided into two different systems. The first
is connected directly with the great central mass inclosed in the skull and spine.
This is called the cerehro-spinal system^ and is divided into the brain (including
the medulla oblongata), the spinal cord, the cranial nerves, the spinal nerves,
and the ganglia connected with both those classes of nerves. The second, called
the sympathetic system., is not directly connected with the brain or spinal cord,
though it is so indirectly by means of its numerous communications with the
cranial and spinal nerves. It consists of a double chain of ganglia, with the
branches which go to and come from them.
A third method of division of the nervous system is based upon the functions
which it performs. On this principle it is divided into the nervous system of
animal life, and the nervous system of organic life — the former subserving the
higher functions of volition, sensation, &c., the latter those of growth and nutri-
tion. It is clear that the former qualities reside mainly in the cerebro-spinal
system, while the intimate connection between the sympathetic nerve and the
great viscera renders it highly probable that the sympathetic system has mainly
to do with the organic functions. Consequently, the cerebro-spinal system was
designated the system of animal life, and the sympathetic the sj^stem of organic
Fig. 32.
Fig. 33.
Nerve vesicles from the Grasserian gan-
glion of the human subject, a, a globular
one with defined border ; b, its nucleus ; e,
Its nucleolus, d, caudate vesicle ; e, elon-
gated vesicle with two groups of pigment
particles; /, vesicle surrounded by its
sheath or capsule of nucleated particles;
g, the same, the sheath only being in
focus. (Magnified 300 diameters.)
Nerve-vesicles from the inner parts of the gray matter
of the convolutions of the human brain: magnified 350
times. Nerve-cells : a, larger, b, smaller, c, nerve-flbre,
with axis-cylinder.
life. But the distinction, though true to a certain extent, is by no means com-
plete, as the student may easily see by consulting the works of modern physi-
ologists.
The gray or vesicular nervous suhstance is distinguished by its dark reddish-
gray color and soft consistence. It is found in the brain, spinal cord, and vari-
ous ganglia, intermingled with the fibrous nervous substance, but is never found
m the nerves. It is composed, as its name implies, of vesicles, or corpuscles,
commonly called nerve- or ganglion-corpuscles, containing nuclei and nucleoli ;
the vesicles being imbedded either in a finely granular substance, as in the brain,
or m a capsule of nucleated cells, as in the ganglia. Each vesicle consists of an
G2
GENERAL ANATOMY.
exceedingly delicate membranous wall, inclosing a finely granular material, part
of wlncli is occasionally of a coarser kind, and of a reddish or yellowisli-brown
color. The nucleus is vesicular, much smaller than the vesicle, and adherent to
some part of its interior. The nucleolus, which is inclosed within the nucleus,
is vesicular in form, of minute size, and peculiarly clear and brilliant. The
nerve-corpuscles vary in shape and size ; some are small, spherical, or ovoidal,
with an uninterrupted outline. These forms are most numerous in the ganglia
of the sympathetic. Others, called cau.date or stellate nerve-corpuscles, are
characterized by their larger size, and from having one or more tail-like pro-
cesses issuing from them, which occasionally divide and subdivide into numerous
branches. These processes are very delicate, apparently tubular, and contain a
similar granular material to that found within the corpuscle. Some of the pro-
cesses terminate in fine transparent fibres, wdiich become lost among the other
elements of the nervous tissue ; others may be traced until, after losing their
granular appearance, they become continuous with an ordinary nerve-fibre.
Fi-. 34.
Fig. 35.
Human nerve-tubes, magnifled 300 times.
Three of them are fine, one of which is vari-
cose, one of middling tliiclcness, and with a
simple contour ; and three thick, two of which
are double contoured, and one with grumous
contents.
c, nerve-tube of the common eel iu water.
The delicate line on its exterior indicates the
tubular membrane. The dark double-edged
inner one is the white substance of Schwann,
slightly wrinkled, b, the same in ether. Seve-
ral oil globules have coalesced in the interior,
and others have accumulated around the ex-
terior of the tube. The white substance has
in part disappeared. (Magnified 300 diameters.)
The white^ otherwise called tubular or fibrous nervous substance^ is found con-
stituting a great part of the brain and spinal cord, almost the whole of the
cerebro-spinal nerves, and a great part of the sympathetic.
The tubes, when perfectly fresh, appear to be homogeneous, but they soon
separate into two parts, the white substance of Schwann and the axis-cylinder of
Purkinje, the whole being inclosed in a membrane — the tubular membrane^^ which
at first appears structureless, but when stained with nitrate of silver is seen to
consist of nucleated endothelial cells. The white substance is regarded as being
a fatty matter in a fluid state, wliich isolates and protects the essential part of
the nerve — the axis-cylinder. Tlie partial coagulation of this white substance
' Dr. Beale describes and fipnres cases in which several fibres, some with, others without. Ihe
white Kul)stiinco, are inclosed in a cnnimnn tnbular inombranc. Soo Phil. Trans., 1862. Latterly
Eiifjlish anlliors have, unCortniiatcly as 1 tliiiik, followed the (Jerinan anatomists in callinpf tiie
tubular membrane wliieh inslieatlies the individual (llires tlie "neurilemma." 'I'hat name should
be reserved lor llie filirons sheath of the entire nerve, which in (lie new nomenclature is called the
" perineurium." These useless changes of names only serve to perplex students.
NERVOUS TISSUE.
f)S
Fig. 36.
whicli follows on cooling gives the nerve-tube, wlien examined after cleatli, a
double contour — the darker part seen on the outside of the axis cylinder being
the white substance of Schwann. In consequence of the extreme delicacy of
the tubular membrane, even slight pressure will often give nerve tubes a varicose
outline, and drops of oil, from the transudation of the fatty matter, often form
outside the tubular membrane. This is, of course, promoted by the action of
ether.
The axis-cylinder constitutes about one-half or one-third of the nerve-tube,
the white substance being greater in proportion in the nerves than in the central
organs. The axis-cylinder is perfectly transparent, and is therefore indistin-
guishable in a perfectly fresh and natural state of the nerve. It is described by
Kolliker as being distinguished from the white substance by the fact that,
though soft and flexible, it is not fluid and viscid, but firm and elastic, some-
what like coagulated albumen, with which it appears for the most part also to
agree in its chemical characters. As ordinarily seen it appears pale and homo-
geneous, or more rarely finely granular or striated.
Besides these nerve-fibres, which consist of two distinct parts, others are
found in which only the axis -cylinder can be recognized, surrounded by its
medullary membrane, whilst there are again mere primi-
tive fibrils found in various parts which are perfectly
destitute of any visible structure, and only recognized
as nerves by their connection with ganglionic cells, or
with obvious nerve-tubes.^ They display a great ten-
dency to become varicose on manipulation. The finely
striated appearance of those nerves, which consist only
of the axis-cylinder and its membranous investment,
renders it probable that these also are formed of an
aggregation of the primitive fibrillse.
Thus three different kinds of white nerve -fibres are
described by recent authorities — viz., 1. Those which
consist of the axis-cylinder, ensheathed in the white sub-
stance of Schwann, the whole being invested by the
tubular membrane ; 2. Those which consist of the axis-
cylinder and medullary membrane only ; and 3. The
primitive fibrils, of which it is believed that the axis-
cylinder of the more composite nerves is made up.^
Most of the nerves of the sympathetic system, and
some of the cerebro- spinal (see especially the description
of the olfactory nerve), consist of a fourth description of
nervous fibres,^ which are called the gray or gelatinous
nerve-fibres (fibres of Remak). (Fig. 36.) These consist of a bundle of finely-
granular fibrilte inclosed in a sheath. Nuclei may be detected at intervals in
each fibre, which Schultze believes to be situated in the sheath of the nerve.
In external appearance the gelatinous nerves are semi-transparent, and gray or
yellowish-gray. The individual fibres vary in size — most of them being of
smaller size than in the cerebro- spinal nerves, so that the average size of the
latter is given at 20V0 fo ■g-o'o^ of an inch, and of the former at only half that
size ; but, on the one hand, the smallest fibrils of the cerebro-spinal system are,
'Schultze (Strieker's Hmi dhncli. ^^. 11 , p. 109) represents these primitive fibrils, both in
their connection with ganglion-cells and with larger nerves. See also below, Fig. 43.
2 Schultze believes that the primitive fibrils are the essential element of all nerves ; +hus,
according to him, the essential difference between the gelatinous and the ordinary nerve fibrils
consists in the absence from the former of the white substance (medulla) of Schwann, while the
tubular membrane is present. The small nerve fibres, on the other hand, described as primitive
fibrils or naked axis-cylinders, are either destitute of any investment, or surrounded merely by a
structureless basement membrane.
' The real nature of these fibres has been doubted by several authors. It seems better, how-
ever, and more consonant with the prevalent opinion, to describe them as truly nervous.
A small nervous branch
from the sympathetic of a
mammal, d, two dark-bor-
dered nerve-tubes among a
number of Eemak's fibres, b.
64 GENERAL ANATOMY.
as we have seen, of liardlj appreciable thickness ; while, on the other, some of
the gelatinous fibres (especially those in the olfactory bulb) are said to be three
or four times as thick as those of the cerebro- spinal nerves.
Chemical composition. The following analysis, by Lassaigne, represents the
relative proportion of the diJferent constituents composing the gray and white
matter of the brain : —
Gray.
White
Water .
. 85.2
73.0
Albuminous matter .....
. 7.5
9.9
Colorless fat
. 1.0
13.9
Red fat
. . . . 3.7
0.9
Osmazome and lactates ....
1.4
1.0
Phosphates
. 1.2
1.3
100.0 100.0
It appears from this analysis that the cerebral substance consists of albumen,
dissolved in water, combined with fatty matters and salts. The fatty matters,
according to Fremy, consist of cerebric acid, which is most abundant, cholesterin,
oleophosphoric acid, and olein, margarin, and traces of their acids. The same
analyst states that the fat contained in the brain is confined almost exclusively
to the white substance, and that its color becomes lost when the fatty matters
are removed. According to Yauquelin, the cord contains a larger proportion
of fat than the brain ; and, according to L'Heritier, the nerves contain more
albumen and more soft fat than the brain.
With regard to the constitution of the different portions of the nervous system,
the cerebro-spinal axis is composed of the two above-described kinds of nervous
structure, intermingled in various proportions, and having in the brain a very
intricate arrangement, which can only be fully understood by a careful study of
the details of its descriptive anatomy in the sequel. The gray or vesicular
nervous matter is found partly on the surface of the brain, forming the convo-
lutions of the cerebrum, which are in the most direct relation to the mental
faculties, and the laminse of the cerebellum, the functions of which are still a
matter of dispute. Again, gray matter is found in the interior of the brain,
collected into large and distinct masses or ganglionic bodies, such as the corpus
striatum, optic thalamus, and corpora quadrigemina ; the functions of which
bodies, so far as they have been ascertained, have been found to be connected
with some of the main organic endowments of the body, such as voluntary
motion, sensation, sight. Finally, gray matter is found intermingled intimately
with the white, and without definite arrangement, as in the corpora dentata of
the medulla and cerebellum, or the gray matter in the pons and the floor of the
fourth ventricle. Such scattered masses of gray matter are, in many instances
at any rate, connected to all appearance with the origin of particular nerves. In
other situations their use is as yet unknown.
The proper nervous matter, both in the brain and spinal cord, is traversed
and supported by a network of fine connective tissue. This has been termed
by Virchow the wewroyZ/a, and is supposed to be the source of one of the forms
of tumor described by that author under the name of glioma.
The white matter of the brain is divisible into four distinct classes of fibres.
There arc, in the first place, the nerves which arise in the gray matter, and pass
out through the cranial foramina. Next, the fibres which connect the brain
with the spinal cord; that is to say, those which are usually traced upwards
from the columns of the spinal cord, through the medulla oblongata into the
cerebrum, cliicfly by means of the anterior pyramids, fasciculi terctcs and resti-
form bodies, passing tlirough the pons and crura cerebri to ex]-)aiul into the
corpora striata, optic thalami and convolutions (corona radiata.), and, by means
of the rostiform bodies, into the cerebellum.
Tlie oilier two classes of white fibres in the brain arc commissural; some of
the commissures serving to connect diffcrcnl paris of tlic same hemisphere
BEAIN. 65
together (as the fornix, the processus e cerebello ad testes, &c.), or even different
parts of the same section or organ, as the arciform fibres of the medulla. Most
of these commissures are longitudinal; while others — as the corpus callosum
and the transverse fibres of the pons Varolii — are transverse, serving to connect
opposite hemispheres together, and thus probably securing the single action of
a double organ.
The following is Dr. Lockhart Clarke's accoimt of the intimate structure of
the cerebral convolutions : —
"Most of the convolutions, when properly examined, may be seen to consist
of at least seven distinct and concentric layers of nervous substance, which are
iilternately paler and darker from the circumference to the centre. The lami-
nated structure is most strongly marked at the extremity of the posterior lobe.
In this situation all the nerve-cells are small, but differ considerably in shape,
and are much more abundant in some layers than in others. In the superficial
layer, which is pale, they are round, oval, fusiform, and angular, but not
numerous. The second and darker layer is densely crowded with cells of a
similar kind, in company with others that are pyriform and pyramidal, and lie
with their tapering ends either towards the surface or parallel with it, in con-
nection with fibres which run in corresponding directions. The broader ends
of the pyramidal cells give off two, three, four, or more processes, which run
partly through the white axis of the convolution, and in part horizontally along
the plane of the layer, to be continuous, like those at the opposite ends of the
cells, with nerve-fibres running in different directions. The third layer is of a
much paler color. It is crossed, however, at right angles by narrow and elon-
gated groups of small cells and nuclei of the same general appearance as those
of the preceding layer. These groups are separated from each other by bundles
of fibres, radiating towards the surface from the central white axis of the convo-
lution, and together with them form a beautiful fanlike structure. The fourth
layer also contains elongated groups of small cells and nuclei, radiating at right
angles to its plane; but the groups are broader, more regular, and, together with
the bundles of fibres between them, present a more distinctly fanlike structure.
The fifth layer is again paler and somewhat white. It contains, however, cells
and nuclei which have a general resemblance to those of the preceding layers,
but they exhibit only a faintly radiating arrangement. The sixth and most
internal layer is reddish gray. It not only abounds in cells like those already
described, but contains others that are rather larger. It is only here and there
the cells are collected into elongated groups, which give the appearance of
radiations. On its under side it gradually blends with the central white axis of
the convolution, into which its cells are scattered for some distance.
"The seventh layer is this central white stem or axis of the convolution. On
every side it gives off bundles of fibres, which diverge in all directions, and in a
fanlike manner, towards the surface, through the several gray layers. As they
pass between the elongated and radiating groups of cells in the inner gray layers,
some of them become continuous with the processes of the cells in the same
section or plane, but others bend round and run horizontally, both in a transverse
and longitudinal direction (in reference to the course of the entire convolution),
and with various degrees of obliquity. While the bundles themselves are by
this means reduced in size, their component fibres become finer in proportion
a,s they traverse the layers towards the surface, in consequence, apparently, of
branches which they give off to be connected with cells in their course. Those
which reach the outer gray layer are reduced to the finest dimensions, and form
a close network with which the nuclei and cells are in connection.
"Besides these fibres which diverge from the central white axis of the convo-
lution, another set, springing from the same source, converge or rather curve
inwards from opposite sides, to form arches along some of the gray layers.
These arciform fibres run in different planes — transversely, obliquely, and longi-
tudinally— .and appear to be partly continuous with those of the diverging set
5
66
GENERAL ANATOMY.
smaller, average diameter than those of the columns
Fij?. 37.
which bend round, as already stated, to follow a similar course. All these fibres
establish an infinite number of communications in every direction, between dif-
ferent parts of each convolution, between difi'erent convolutions, and between
these and the central white substance."
Dr. Clarke then goes on to describe in detail the minuter differences which
exist between the structure of the convolutions in different parts of the brain.^
Spinal Cord. In the spinal cord, on the other hand, the gray matter is entirely
in the interior of the organ, and is collected together into one central mass, while
the whole of the white matter is external, and is arranged into various columns
and commissures, which will be fully described hereafter. We shall here
merely give an account of the intimate structure of the cord, which is condensed
from the researches of Dr. Lockhart Clarke.^
The white substance of the cord consists of transverse, oblique, and longitudinal
fibres, with bloodvessels and connective tissue.
The transverse fibres proceed from the gray substance, and form with each
other a kind of plexus between the bundles of longitudinal fibres, with which
many are continuous ; while others reach the surface of the cord through fissures
containing connective tissue. Within the gray substance they are continuous
with the roots of the nerves, with the processes of the nerve cells, and with the
anterior and posterior commissures. The oblique fibres proceed from the gray
substance both upwards and downwards ; they form the deep strata of the white
columns, and, after running a variable length, become superficial. The longi-
tudinal fi^bres are more superficial, run nearly parallel with each other, and form
the greater portion of the white columns.
The gray substance of the cord consists of, 1. JSTerve-fibres of variable, but
2. Nerve-cells of various
shapes and sizes, with from two to
eight processes ; 3. Bloodvessels and
connective tissue.
Each lateral half of the gray sub-
stance is divided into an interior and
posterior horn, and the tractus inter-
medio-lateralis, or lateral part of the
gray substance between the anterior
and posterior cornua.
The jMsterior horn consists of two
parts, the caput cornu, or expanded
extremity of the horn (Fig. 37),
round which is the lighter space or
lamina, the gelatinous substance and
the cervix cornu or remaining narrow
portion of the horn, as far forwards
as the central canal.
The gelatinous substance contains
along its border a series of large
nerve-cells ; but more internally
consists of a stratum of small cells
traversed by transverse, oblique, and longitudinal fibres. (Figs, 38, 39.)
Nearly the whole inner half of the cervix is occupied by a remarkable and
important column of nerve-cells, called the posterior vesicular column (Fig. 37),
which varies in size and appearance in different regions of the cord, and is
intimately connected with the posterior roots of the nerves.
Within, and along the outer Ixn-dor of the cervix, are several thick bundles
' Poo Dr. Clarke's Riimmnry of his resctirchos on tliis subject in Mandsley on the Patholoijy
and Phyninlfxjy of Mind. pp. 00-6!}.
2 Phil. Trans., 18.51-18.53. part iii. ; 18.58, part i. ; 1859, part i. ; 18G2, part ii.
Transverse section of the gray substance of the spinal
cord, near the mitUlle of the dorsal region. (Magnified 13
diameters.)— J. L. Clarke, del.
SPINAL CORD.
Fig. 38.
67
GfUH
Transverse section of the gray substance of the spinal cord through the middle of the lumbar enlargement.
On the left side of the figure groups of large cells are seen ; on the right side, the course of the fibres is shown
without the cells. (Magnified 13 diameters.) — J. L. Clarke, del.
of longitudinal fibres, represented in Fig. 37 by
the dark spots ; other bundles of the same
kind may be seen in the gray substance along
the line of junction of the caput with the cer-
vix cornu. (Fig. 38.)
The anterior horn of the gray substance in
the cervical and lumbar swellings, where it
gives origin to the nerves of the extremities, is
much larger than in any other region, and con-
tains several distinct groups of large and
variously-shaped cells. This is well shown on
comparing the above figures.
The tractus inter medio -lateralis (Fig. 37) ex-
tends from the upper part of the lumbar to the
lower part of the cervical enlargement, and
consists of variously-shaped cells, which are
smaller than those of the anterior cornu. In
the neck, above the cervical enlargement, a
similar tract reappears, and is traversed by the
lower part of the spinal accessory nerve.
Origin of the Spinal Nerves in the Cord. The
posterior roots are larger than the anterior ; but
their component filaments are finer and more
delicate. They are all attached immediately
to the posterior columns only, and decussate
with each other in all directions through the
columns ; but some of them pass through the
gray substance into both the lateral and ante-
rior columns. "Within the gray substance they
Fisr. 39.
Longitudinal section of the white and
gray substance of the spinal cord, through
the middle of the lumbar enlargement,
(Mag. 14 diam.)— J. L. Clarke, del.
68 GENERAL ANATOMY.
run longitudinally upwards and downwards ; transversely tlirougL. the posterior
commissure to the opposite side ; and into the anterior cornu of their own side
(Figs. 38, 39.)
The anterior roots are attached exclusively to the anterior column, or rather
to the anterior part of the antero-lateral columns, for there is no antero-lateral
fissure dividing the anterior from the lateral column. Within the gray substance
the fibrils cross each other, and diverge in all directions, like the expanded hairs
of a brush (Figs. 38, 39), some of them running more or less longitudinally up-
wards and downwards ; and others decussating with those of the opposite side
through the anterior commissure in front of the central canal.
All the fibres of both roots of the nerves proceed through the white columns
into the gray substance, with, perhaps, the exception of some which appear to
run longitudinally in the posterior columns ; but whether these latter fibres of
the posterior roots ultimately enter the gray substance of the cord, after a very
oblique course, or whether they proceed upwards to the brain, is uncertain.
The Central Ca7ial of the Spinal Cord. In the foetus until after the sixth
month, a canal, continuous with the general ventricular cavity of the brain,
extends throughout the entire length of the spinal cord, formed by the closing-
in of a previously open groove.
In the adult, this canal can only be seen at the upper part of the cord extend-
ing from the point of the calamus scriptorius, in the floor of the fourth ventricle,
for about half an inch down the centre of the cord, where it terminates in a
cul-de-sac ; the remnant of the canal being just visible in a section of the cord,
as a small pale spot, corresponding to the centre of the gray commissure ; its
cavity is lined with a layer of cylindrical ciliated epithelium. In some cases,
this canal remains pervious throughout the whole length of the cord.
The Ganglia may be regarded as separate and independent nervous centres,
of smaller size and less complex structure than the brain, connected with each
other, with the cerebro-spinal axis, and with the nerves in various situations.
The}^ are foimd on the posterior root of each of the spinal nerves ; on the pos-
terior or sensory root of the fifth cranial nerve ; on the facial nerve ; on the
glosso-pharyngeal and pneumogastric nerves ; in a connected series along each
side of the vertebral column, forming the trunk of the sympathetic ; on the
branches of that nerve, and at the point of junction of those branches with lhe
cerebro-spinal nerves. On section, they are seen to consist of a reddish-gray
substance, traversed by numerous white nerve-fibres : they vary considerably
in form and size ; the largest are found in the cavity of the abdomen ; the
smallest, not visible Avith the naked eye, exist in considerable numbers upon the
nerves distributed to the different viscera. The ganglia are invested b}^ a smooth
and firm closelj^-adhering membranous envelope, consisting of dense areolar
tissue ; this sheath is continuous with the neurilemma of the nerves, and sends
numerous processes into the interior of the ganglion, which support the blood-
vessels supplying its substance.
In structure, all ganglia are essentially similar, consisting of the same struct-
ural elements as the other nervous centres — viz., a collection of vesiciilar nervous
mcttter, traversed by tubular and gelatinous nerve-fihres. The vesicular nervous
matter consists of nerve-cells or ganglion-globules, most of which appear free,
and of a round or oval form ; these are more especially seated near the surface
of the ganglion ; others have caudate processes, and give origin to nerve-fibres.
In the gangli(m, the nerve-cells arc usually inclosed in a capsule of granular
corpuscles and fibres. The tubular nerve-fibres run through the ganglion, some
being collected into bundles, while others, separating from each other, lake a
circuitous course among the nerve-cells before leaving the ganglion.
The Nerves arc round or flal toned cords, Avhicli arc connected at one end with
the cerebro-spinal centre or with the gangliji, and are distributed at the other to
THE NERVES. 69
the various textures of tlie body : tliey are subdivided into two great classes,
the cerebro-spinal, which proceed from the cerebro-spinal axis, and the sympa-
thetic or gauglionie nerves, which proceed from the gangha of the sympathetic.
The Cerebrospinal nerves consist of numerous nerve-fibres, collected together
and inclosed in a membranous sheath. A small bundle of primitive fibres, in-
closed in a tubular sheath, is called Si funiculus ; if the nerve is of small size it
may consist only of a single funiculus, but if large, the funiculi are collected
together into larger bundles ox fasciculi; and are bound together in a common
membranous investment, termed the sheath. In structure the common sheath
investing the whole nerve, as well as the septa given off from the sheath, and
which separate the fasciculi, consist of areolar tissue, composed of white and
yellow elastic fibres, the latter existing in greatest abundance. The tubular
sheath of the funiculi, or neurilemma {perineurium of later German authors),
consists of a fine, smooth, transparent membrane, which may be easily separated,
in the form of a tube, from the fibres it incloses ; in structure, it is for the most
part a simple and homogeneous transparent film, occasionally composed of
numerous minute reticular fibres.
The cerebro-spinal nerves consist almost exclusively of the tubular nerve-
fibres, the gelatinous fibres existing in very small proportion.
In the tubular nerve-fibres Ranvier has lately pointed out a peculiar arrange-
ment, brought into view by the action of osmic acid, and to which the name of
the nodes of Ranvier is given. The axis-cylinder and the medullary substance
are stained black by the reagent, while the tubular sheath is unstained. Each
fibre, when so treated, is seen to be interrupted at regular intervals by a break
in the white substance of Schwann, and at these breaks or nodes the tubular
membrane seems to turn in and invest the axis-cylinder, which runs uninter-
rupted across the break. A nucleus is also thus brought into view in the centre
of each segment of the nerve, lying in the tubular sheath.
The bloodvessels supplying a nerve terminate in a minute capillary plexus,
the vessels composing which run, for the most part, parallel with the funiculi ;
they are connected together by short transverse vessels, forming narrow oblong
meshes, similar to the capillary system of muscle.
The nerve-fibres, as far as is at present known, do not coalesce, but pursue an
uninterrupted course from the centre to the periphery. In separating a nerve,
however, into its component funiculi, it may be seen that they do not pursue a
perfectly insulated course, but occasionally join at a very acute angle with other
funiculi proceeding in the same direction ; from which again branches are given
off to join again in like manner with other funiculi. It must be remembered,
however, that in these communications the nerve-fibres do not coalesce, but
merely pass into the sheath of the adjacent nerve, become intermixed with its
nerve-fibres, and again pass on to become blended with the nerve-fibres in some
adjoining fasciculus.
Nerves, in their course, subdivide into branches, and these frequently com-
municate with branches of a neighboring nerve. In the subdivision of a nerve,
the filaments of which it is composed are continued from the trunk into the
branches, and at their junction with the branches of neighboring nerves the
filaments pass to become intermixed with those of the other nerve in their
further progress ; in no instance, however, have the separate nerve-fibres been
shown to inosculate.
The communications which take place between two or more nerves form what
is called a plexus. Sometimes a plexus is formed by the primary branches of
the trunks of the nerves, as the cervical, brachial, lumbar, and sacral plexuses,
and occasionally by the terminal fasciculi, as in the plexuses formed at the
periphery of the body. In the formation of a plexus the component nerves
divide, then join, and again subdivide in such a complex manner that the indi-
vidual fasciculi become interlaced most intricately ; so that each branch leaving
a plexus may contain filaments from each of the primary nervous trunks which
70 GENERAL ANATOMY.
form it. In tlie formation also of tlie smaller plexnses at the periphery of tlie
body, there is a free interchange of the fasciculi and primitive fibrils. In each
case, however, the individual filaments remain separate and distinct, and do not
inosculate with each other.
It is probable that, through this interchange of fibres, the different branches
passing off" from a plexus have a more extensive connection with the spinal cord
than if they each had proceeded to be distributed without such connection with
other nerves. Consequently, the parts supplied by these nerves have more
extended relations with the nervous centres ; by this means, also, groups of
muscles may be associated for combined action.
The Sym.pathetic nerve consists of tubular and gelatinous fibres, intermixed
with a varying proportion of filamentous areolar tissue, and inclosed in a sheath
formed of fibro-areolar tissue. (Fig. 36.) The tubular fibres are, for the most
part, smaller than those composing the cerebro-spinal nerves ; their double
contour is less distinct, and, according to Eemak, the present nuclei similar to
those found in the gelatinous nerve-fibres. Those branches of the sympathetic
which present a well-marked gray color are composed more especially of gela-
tinous nerve-fibres, intermixed with a few tubular fibres ; whilst those of a white
color contain more of the tubular fibres and a few gelatinous. Occasionally, the
gray and white cords run together in a single nerve, without any intermixture,
as in the branches of communication between the sympathetic ganglia and the
spinal nerves, or in the communicating cords between the ganglia.
The nerve-fibres, both of the cerebro-spinal and sympathetic system, convey
impressions of a twofold kind. The sensory nerves, called also centripetal or
afferent nerves, transmit to the nervous centres impressions made upon the
peripheral extremities of the nerves, and in this way the mind, through the
medium of the brain, becomes conscious of external objects. The motor nerves,
called also centrifugal or efferent nerves, transmit impressions from the nervous
centres to the parts to which the nerves are distributed, these impressions either
exciting muscular contractions, or influencing the processes of nutrition, growth,
and secretion.
Terminations of Nerves. By the expression " the termination of nerve-fibres"
is signified their connections with the nerve-centres and with the parts which
they supply. Tlie former are called their central^ the latter their peripheral
terminations. With regard to the central terminations of the nerves, little is
as yet certainly known.^ The nerve-cells, or nerve-corpuscles, above figured,
have been regarded as the central origin of the fibres with which they are con-
nected ; and it is very probable that in many cases they are so. There are
instances, however, in which such cells occur as mere nucleated swellings in the
course of a nerve, and in these cases they obviously cannot be regarded as being
in any sense the origins of the nerves. In other cases, as in the nerve-cells in
the anterior horn of the gray matter of the cord, there are numerous processes
springing out of the cell ; one of these (and, according to Deiters, one only) is
recognized as an axis-cylinder ; the others are fibrilljB, which are continuous
with similar fibrilloe, of which under high poAvers the apparently gi'anular con-
tents of the cell are found to be composed, and which appear, therelbre, simply
to run through the cell. The fibrillce may be, and probably are, primitive
nervous fibrils, but they are so delicate that it has not as yet been found possible
to ascertain their destination. With regard also to the axis-cylinder which is
seen proceeding out of the ganglionic corpuscle, although it is highly probable
that it originates in that corpuscle, the fact has not been proved — nor has its
relation to the nucleus of tiic corpuscle been demonstrated. In fine, all that is
' One of the most recent and most tlistinfruished observers on tliis subject. Max Sclniltze, speaks
thus : " In the present state of onr knovvledfife, we are not in a position to assign its central orip-in
to any sinj^i-le primitive fll)ril of th(! nervous system, however certainly we may have discovered
the peripheral terminations of a great part of ihcm." — Schultze, in Strieker's Ilandbiich, 18G8,
p. i;{4.
THE NEEVES. 71
known on tlie subject is, that many of tlie fibrillee and axis-cylinders can be
shown either to originate in or to pass through ganglionic corpuscles (or nerve-
cells), and other nerves can be shown to contain such nerve-cells in their interior
at certain parts of their course. But whether in the case of such connection in
one of the central organs the cell is to be regarded as the origin of the nervous
fibril, or whether the fibril merely passes through the cell (as some observers
believe), just in the same manner as nerves pass through ganglia, has not been
determined. If the latter view be correct, it may be that nerves have really
no central termination, but that their fibrils start from their peripheral distribu-
tion, travel to the nervous centre, are there brought into connection with the
nerve-cells, and thence return to their distribution. However, in the present
state of anatomical knowledge, the more probable opinion seems to be that which
is usually entertained : viz., that each nerve-fibre is connected somewhere with a
ganglionic corpuscle which is to be regarded as its central terminatfon or origin.
Dr. Beale asserts that even in those ganglion-cells, which appear either altogether
destitute of processes, or unipolar, numerous fibres can be seen proceeding out
of them if the proper reagents be used and very high powers employed.
The peripheral connections, or terminations of the nerve-fibres, are somewhat
more easy to ascertain, though even as to these a great difference exists with
respect to minute details. They are usually and naturally studied in the sensory
and motor nerves separately.
Sensory nerves sometimes terminate in minute plexuses in the subcutaneous
or submucous areolar tissue. Dr. Sharpey says that he has seen the ultimate
fibres of these minute plexuses come into close contact with the connective-tissue
corpuscles, but has not been able to trace any distinct connection between them.
Frey has lately described and figured a large number of microscopic ganglia on
this submucous nervous plexus. Similar ganglia were long ago described by
J. Miiller in the corpora cavernosa, and they may apparently be met with in
many other parts.
The white substance of Schwann and the tubular sheath usually disappear as
the nerve approaches its termination, leaving only the axis-cylinder invested by
its proper basement- membrane, on which nuclei can be seen at intervals, and
in many cases the axis-cylinder itself breaks up into the primitive fibrils. In
some parts, however, the fibres appear to be inclosed up to their termination in
a sheath which is either a ]Drolongation of the neurilemma or a continuation of
the tubular membrane. The differences of opinion prevailing on the question
of the ultimate distribution of the nerve-fibres depend on their extreme delicacy
and the consequent great difficulty of following individual fibres in continuity.
Hence what some observers describe as a free end in which the nerve terminates,
others regard as merely a bending of the fibre where it becomes lost to sight, or
a spot where it is lost sight of in consequence of the power used being too low,
or from difficulty in focussing. These ultimate fibres, it should be remembered,
are structureless, and can therefore only be recognized positively as nervous by
their continuity with a nerve of more complex structure.
In the papillae of the skin, or mucous membrane, and on the surface of various
membranes (conjunctiva, mesentery, &c.), three diffbrent kinds of terminal organs
have been found connected with the nerves ; viz., the end-bulbs of Krause, the
tactile corpuscles of Eudolph Wagner, and the Pacinian corpuscles.
The end-bulbs of Krause are small capsules of connective tissue, in which
nuclei can be detected by reagents, and in which one or more nerve-fibrils
terminate either in a coiled plexiform mass or in a bulbous extremity. They
have been described as occurring in the conjunctiva, the mucous membrane of
the mouth, and the surface of the glans penis and glans clitoridis.^
The tactile co7yuscles of Wagner (Fig. 40) are described by him as oval-shaped
bodies, made up of superimposed saccular laminae, presenting some resemblance
' Krause, Die tei-minalen K6rperclie7i, 1860. Anatomisdie Uiitersuchungen, 1861.
72
GENERAL ANATOMY.
to a miniature fir-cone, and he regarded tliem as directly concerned in tlie sense
of toucli. Ktilliker considers that the central part of the papillse generally
consists of a connective tissue more homogeneous than that of the outer part,
surrounded by a sort of sheath of elastic fibres, and he believes that these
corpuscles are merely a variety of this structure. The 'nerve-fibres, according
to this observer, run up in a waving course to the corpuscle, not penetrating it,
but forming two or three coils round it, and finally join together in loops. These
Fig. 40.
A, Side view of a papilla of the hand, a, cortical layer ;
b, tactile corpuscle, with transverse nuclei ; c, small nerve
of the papilla, with neurilemma; d, its two nervous
fibres running with spiral coils arounil the tactile cor-
puscle ; e, apparent termination of one of these fibres.
B, A tactile papilla seen from above, so as to show its
transverse section, a, cortical layer; 6, nerve-fibre; c,
outer layer of the tactile body, with nuclei ; d, clear
interior substance. From the human subject, treated
with acetic acid. (Magnified 350 times.)
Pacinian cor])uscle Avith its system of cap-
sules and central cavity, a, arterial twig, end-
ing in capillaries, which form loops in some of
the intercapsular spaces, and one penetrates to
the central capsule; b, the fibrous tissue of the
stalk prolonged from the neurilemma ; n, nerve-
tube advancing to the central capsules, there
losing its v/hite substance, and stretching along
the axis to the opposite end, where it is fixed
by a tubercular enlargement.
bodies are not found in all the papillaa ; but, from their existence in those parts
in which the skin is highly sensitive, it is probable that they are specially con-
cerned in the sense of touch, though their absence from the papillas of other
tactile parts shows that they are not essential to this sense.
The Pacinian corpuscles^ (Fig- 4:1) are found in the human subject chiefly on
the nerves of the fingers and toes, lying in the subcutaneous cellular tissue ; but
they have also been described by Rauber as connected with the nerves of the
joints, and with the nerves lying between many of the muscles of the trunk and
limbs. Each of these corpuscles is attached to and incloses the termination of
a single nerve. The corpuscle, wliich is perfectly visible to the naked eye (and
which can be most easily demonstrated in the mesentery of a cat), consists of a
number of concentric layers of cellular tissue, between which Todd and Bowman
have figured capillary vessels as running. The nerve, at its entrance into this
Oft(
Icil ill r.'eniiun Aiuitomical works "corpuscles of Vatcr."
THE NERVES. 73
body, parts with its wliite substance, and the axis-cylinder runs forwards in a
kind of cavity in the centre of the corpuscle to terminate in a rounded end or
knob, sometimes bifurcating previously, in which case each branch has a similar
termination. Grandry, who has examined these corpuscles with very high magni-
fying powers, describes the axis-cylinder as exhibiting a very well marked
fibrillar structure, and the bulbous end as consisting of a mass of granules into
which the fibrils run, diverging as they approach it. The investing capsules are
from thirty to sixty in number, the outer being more separated from each other,
as if by a clear fluid, while the inner are closel}' applied together. Schultze calls
attention to the striking resemblance in all essential particulars between these
corpuscles and Krause's end-bulbs above described.^
In the special organs the nerves end in various ways, which hitherto are not
perfectly known.
Hoyer and Cohnheim have described the nerves of the cornea as terminating
in primitive fibrillee, which run between the cells forming the pavement-epithe-
lium of that membrane, and end on its free surface. This, however, is doubted
by Hulke,^ who has only succeeded in tracing them as far as the middle tier of
the epithelial cells, Schultze discovers in the olfactory mucous membrane,
lying between the cells of its epithelium, spindle-shaped cells, each possessing a
central and a peripheral process — the central process being, according to him,
continuous with a primitive fibril of the olfactory nerve, and the peripheral
process either ending on the free surface of epithelium, as is the case in men,
mammals, and fishes, or, as in some other animals, jDrolonged into a long stiff
hair. These cells he has denominated "olfactory cells;" and similar cells have
been described by Axel Key, Schwalbe, and Loven, in the papillte circumvallatje
of man, and the fungiform papillee of the frog (" taste cells"). The fibres also of
the optic nerve have, according to Schultze, a similar connection with the cells
("sight-cells") of the retina; and cells somewhat similar, and connected with pro-
cesses that pass through the epithelium, are to be found on the nerve fibrils of
the auditory nerve, in the membranous labyrinth ("hearing-cells").
The termination of the nerves in the hair-bulbs is probably to be found in the
papillae at their root, as is also the case in the teeth. In glands the nerves,
according to Pfliiger, are connected with the csecal commencements of the gland-
tubes — at least he has described this arrangement in the salivary glands, and
thus he is led to regard the nuclei of these cgecal pouches as the terminations of
the nerves.
Motor nerves are to be traced either into unstriped or striped fibres.
In the unstriped fibres it appears from the researches of Beale, Franken-
hauser, and Julius Arnold, that tlie ultimate fibrils of the nerves form plexuses
at the junctions of whose branches small nuclear bodies are situated. These
nuclei are regarded by Arnold as the real terminations of the nerves ; for al-
though he agrees with Frankenhauser in stating that the nervous filaments pene-
trate the muscular fibres, and enter into relation with the granular contents of .
their nuclei, he traces the filaments back again from that point to the nuclei
situated at the junctions of the nervous plexuses, in the connective tissue of the
muscular fibres.
In the voluntary muscles Beale and Kolliker have described the nerve -fibres
as terminating either in a plexiform arrangement, or (according to the latter
author) sometimes in free ends between the muscular fibres external to the
sarcolemma. Lately another method of termination, which had been formerly
described, has received the support of numerous eminent authorities — -viz., the
^'■motorial end-plates^'' of Kiihne, or "nerve-hillocks" (nerve-tufts) of Doy^re,
The latter author had described, nearly thirty years ago, a connection between
the nervous and muscular fibres in some of the lower animals, consisting in an
' Strieker's ffandbnch, p. 123.
2 Lectures on the History of the Bye, at the Royal College of Surgeons, June 1869.
74
GENERAL ANATOMY.
elevation at tlie point of junction of tlie two, wliere the sarcolemma of the
muscular fibre became blended with the tubular membrane of the nerve. This
has been since so far confirmed bj subsequent researches that it seems well to
figure, from the most recent author, Kiihne, what he supposes to be the termina-
tion of all motor nerves of voluntary muscles. The following is Kiihne's de-
scription of the method of connection : —
" In all striped muscles the nerves terminate below the sarcolemma — the tubu-
lar membrane being blended with the sarcolemma. The white substance accom-
a
Muscular fibres of Ij.acerta viriclis with the terminations of nerves, a, seen in profile ; p p, the nerve-end-
plates ; S s, the base of the plate, consisting of a granular mass with nuclei, h, the same as seen iu looking
at a perfectly fresh fibre, the nervous ends being probably still excitable. (The forms of the variously-
divided plate can hardly be represented in a woodcut by sufficiently delicate and pale contours to reproduce
correctly what is seen in nature.) c, the same as seen two hours after death from poisoning by curare.
panics the axis-cylinder as far as this point. The ending of the axis-cylinder
always represents an expansion with a considerably increased surface, and this
is constantly formed by its branching out on a flat plate. This nerve-end-plate
is sometimes more like a membrane, at others like a system of fibres. In most
cases the plate rests upon a base of granules and finely- granular protoplasm ;
in other cases, there is no such support, and the nerve- plates then possess the
so-called nerve-end-bulbs. The ends of the nerves never penetrate the interior
of the contractile cylinder, nor does the plate ever embrace the whole circum-
ference of the cylinder. Short muscular fibres generally have only one nerve-
end, while longer fibres have several."
It is right, however, to state that the most eminent English authority on this
subject entirely denies the description above given, and explains the appearances,
figured by KUhne and others, in a different manner. In a very interesting paper
by Dr. Beale, published in 1867,' he endeavors to show that the nerve-hillocks
of Doy^re are merely accidental elevations produced by the sarcolemma being
drawn up in a cone, as the nerve which is attached to it is stretched by the
manipulation of the observer; and with reference to the end-plates of Kiihne,.
he asserts that by his own method of examination he is able to follow the nerve-
fibrils much beyond the point at which that author describes them as terminating.
The appearance of their penetrating the sarcolemma he regards as an optical
illusion, and the nuclei shown in the above figures are, according to him,
situated outside of the muscular fibres on the point of junction of the fibrils
which form the intricate and extensive plexus in which the nerves terminate,
so that the nerves nowhere terminate in free ends, nor at any definite part of
the fibre; but, on the contrary, surround every point of the latter with a very
close interlacement.
' On Anatomical Controversy. Beale's Archives, iv. 161.
THE ARTERIES.
75
By tile kindness of Dr. Beale we are enabled to reproduce some of tlie figures
representing preparations which he exhibited to the British Medical Association
at Oxford in 1868, in illustration of this view.
Fig. 43.
Terminations of motor nerves, according to Beale. 1. Nerve-tuft on the sarcolemma of a muscular fibre;
chameleon. Nerve-fibres are seen passing out of as well as into the tuft. 2. Nerve-fibres distributed to ele-
mentary muscular fibre; chameleon, X3000, and reduced half. This is a very simple form of "nerve-tuft,"
clearly external to the sarcolemma. 3. The intimate structure of a very simple "nerve-tuft" on a muscular
fibre of the chameleon. It will be observed that the nerve-fibres are continuous throughout, and that the
whole is on the surface of the sarcolemma, X3000. This " nerve-tuft" is, as it were, but a compound network.
THE VASCULAE SYSTEM.
The Yascular System, exclusive of its central organ, the Heart, is divided into
four classes of vessels — the Arteries, Capillaries, Yeins, and Lymphatics — the
minute structure of which we will now proceed briefly to describe, referring the
reader to the body of the work for all that is necessary in the details of their
ordinary anatomy.
Structure of Arteries. The arterieis are composed of three coats: internal
serous, or epithelial coat (tunica intima of Kcilliker), middle fibrous or circular
coat, and external cellular coat, or tunica adventitia.
The two inner coats together are very easily separated from the external, as
by the ordinary operation of tying a ligature on the artery. If a fine string be
tied forcibly upon an artery, either before or after death, and then taken off, the
76
GENERAL ANATOMY.
external coat will be found uninjured, but the internal coats are divided in the
track of the ligature, and can easily be further dissected from the outer coat.
The inner coat can be separated from the middle by a little maceration.
The inner coat consists of — 1. A layer of pavement-epithelium, the cells of which
are polygonal, oval, or fusiform, and have very distinct nuclei. This epithelium
is brought into view most distinctly by staining with nitrate of silver. 2. This
epithelium rests upon a layer of longitudinal elastic fibres, in which, under the
microscope, small elongated apertures are seen, and which was therefore called
by Henle \h.Q _fenestrated memhrane. This layer is marked with numerous
reticulations ; it is perfectly smooth when the artery is distended ; but when
empty, presents longitudinal and transverse folds. The fenestrated membrane
can often be separated into more than one layer.
In arteries of less than a line in diameter, the internal coat consists of two
layers, as above described ; ■ but in middle-sized arteries, several lamellee, com-
posed of elastic fibres and connective tissue, are interposed between the epithelial
and middle coats. In the largest arteries, the inner coat is usually much thick-
ened, especially in the aorta; and consists of a homogeneous substance, occa-
sionally striated or fibrillated, traversed by longitudinal elastic networks which
are very fine in the lamellse immediately beneath the epithelium, but increase
in thickness from within outwards. The internal and middle coats are separated
by either a dense elastic reticulated coat, or a true fenestrated membrane.
The middle coat is distinguished from the inner by its color, and by the trans-
verse arrangement of its fibres, in contradistinction to the longitudinal direction
of those of the inner coat. In the largest arteries, this coat is of great thickness,
of a yellow color, and highly elastic ; it diminishes in thickness and becomes
redder in color as the arteries become smaller; becomes very thin, and finally
disappears. In small arteries, this coat is purely muscular, consisting of mus-
Fig. 44.
An artery from the mesentery of a ehild, .002'", and 6, vein .Ou7"'. in diamoter (treated with acetic acid and
magniHcd 350 times.) a, tunica adventitia, with elonRated nuclei. /?, nuclei of the contractile fibre-cells of the
tunica media, seen partly from the surface, partly apparent in transverse section, y, nuclei of the epithelial
cells. J, clastic longitudinal fibrous coat.
ciilar fibro.-cclls (Fig. 31), miilod 1o fonn lamellae which vary in number accord-
ing to the size of the artery, the very small arteries having only a single layer
and those not larger than \\i\i of a line in diameter, three or four layers. In
arteries of medium size, this coat becomes thicker in proportion to the size of
THE ARTERIES. 77
tlie vessel ; its layers of muscular tissue are more numerous, and intermixed witli
numerous fine elastic fibres wliicli unite to form broad-meslied networks. In the
larger vessels, as tlie femoral, superior mesenteric, cceliac, external iliac, brachial
and popliteal arteries, the elastic fibres unite to form lamellee, which alternate
with the layers of muscular fibre. In the largest arteries, the muscular tissue
is only slightly developed, and forms about one-third or one-fourth of the whole
substance of the middle coat ; this is especially the case in the aorta, and trunk
of the pulmonary artery, in which the individual cells of the muscular layer are
imperfectly formed ; while in the carotid, axillary, iliac, and subclavian arteries,
the muscular tissue of the middle coat is more developed. The elastic lamellae
are well marked, may amount to fifty or sixty in number, and alternate regularly
with the layers of muscular fibre. They are most distinct, and arranged with
most regularity, in the abdominal aorta, innominate artery, and common carotid.
The external coat consists mainly of connective tissue, and contains elastic
fibres in all but the smallest arteries. In the largest vessels, the external coat is
relatively thin ; but in small arteries, it is as thick, or thicker, than the middle
coat. In arteries of the medium size, and above it, the external coat is formed
of two layers, the outer of which consists of connective tissue, containing an
irregular elastic network, while the inner is composed of elastic tissue only. The
inner elastic layer is very distinct in the carotid, femoral, brachial, profunda,
mesenteric and coeliac arteries, the elastic fibres being often arranged in lamellae.
In the smaller arteries, the former layer of mixed connective tissue and elastic
fibres composes the whole of the external tunic; while in the smallest arteries,
just above the capillaries, the elastic fibres are wanting, and the connective tis-
sue of which the coat is composed becomes more homogeneous the nearer it ap-
proaches the capillaries, and is gradually reduced to a thin membranous envel-
ope, which finall}^ disappears.
Some arteries have extremely thin coats in proportion to their size ; this is
especially the case in those situated in the cavity of the cranium and spinal canal,
the difference depending on the greater thinness of the external and middle coats.
The arteries, in their distribution throughout the body, are included in a thin
areolo-fibrous investment, which forms what is called their sheath. In the limbs,
this is usually formed by a prolongation of the deep fascia; in the upper part
of the thigh, it consists of a continuation downwards of the transversalis and iliac
fasciae of the abdomen ; in the neck, of a prolongation of the deep cervical fascia.
The included vessel is loosely connected with its sheath by a delicate areolar
tissue; and the sheath usually incloses the accompanying veins, and sometimes
a nerve. Some arteries, as those in the cranium, are not included in sheaths.
All the larger arteries are supplied with bloodvessels like the other organs
of the body; they are called vasa vasorum. These nutrient vessels arise from
a branch of the artery or from a neighboring vessel, at some considerable dis-
tance from the point at which they are distributed ; they ramify in the loose are-
olar tissue connecting the artery with its sheath, and are distributed to the ex-
ternal and middle coats, and, according to Arnold and others, supply the internal
coat. Minute veins serve to return the blood from these vessels; they empty
themselves into the venae comites in connection with the artery.
Arteries are also provided with nerves, which are derived chiefly from the
sympathetic, but partly from the cerebro- spinal system. They form intricate
plexuses upon the surfaces of the larger trunks, the smaller branches being usually
accompanied by single filaments. Microscopists are not absolutely agreed as to
the node of termination of the vascular (or vasomotor) nerves. Frey, following
Arnold, has figured an intricate plexus of simple fibres ramifying among the
muscular fibre-cells of an artery in the frog, and Dr. Beale has described minute
ganglia seated on the ultimate fibres. According to Kolliker, the majority of
the arteries of the brain and spinal cord, those of the choroid and of the placenta,
as well as many arteries of muscles, glands, and membranes, are unprovided with
nerves.
78 GENERAL ANATOMY.
The Capillaries. The smaller arterial branches (excepting those of the cavern-
ons structures of the sexual organs, and in the uterine placenta) terminate in a
network of vessels which pervade nearly every tissue of the body. These
vessels, from their minute size, are termed capillaries {capillus^ " a hair"). They
are interposed between the smallest branches of the arteries and the commencing
veins, constituting a network, the branches of which maintain the same diameter
throughout, the meshes of the network being more uniform in shape and size
than those formed by the anastomoses of the small arteries and veins.
The diameter of the capillaries varies in the different tissues of the body, their
usual size being about ^Tj'oo-th of an inch. The smallest are those of the brain,
and the mucous membrane of the intestines ; the largest, those of the skin, and
the marrow bones.
The form of the capillary net varies in the different tissues, being modifica-
tions chiefly of rounded or elongated meshes. The rounded form of mesh is most
common, and prevails where there is a dense network, as in the lungs, in most
glands and mucous membranes, and in the cutis ; the meshes being more or
less angular, sometimes nearly quadrangular, or polygonal ; more frequently,
irregular. Elongated 'ineshes are observed in the bundles of fibres and tubes
composing muscles and nerves, the meshes being usually of a parallelogram
form, the long axis of the mesh running parallel with the long axis of the nerve
or fibre. Sometimes, the capillaries have a looped arrangement, a single vessel
projecting from the common network, and returning after forming one or more
loops, as the papilla of the tongue and skin.
The number of the capillaries, and the size of the meshes, determine the
degree of vascularity of a part. The closest network, and the smallest inter-
spaces, are found in the lungs and in the choroid coat of the eye. In the liver
and lung, the interspaces are smaller than the capillary vessels themselves. In
the kidney, in the conjunctiva, and in the cutis, the interspaces are from three
to four times as large as the capillaries which form them ; and in the brain from '
eight to ten times as large as the capillaries, in their long diameter, and from
four to six times as large in their transverse diameter. In the cellular coat of
the arteries, the width of the meshes is ten times that of the capillary vessels.
As a general rule, the more active the function of an organ is, the closer is its
capillary net, and the larger its supply of blood, the network being very narrow
in all growing parts, in the glands, and in the mucous membranes ; wider in
bones and ligaments, which are comparatively inactive ; and nearly altogether
absent in tendons and cartilages, in which very little organic change occurs after
their formation.
Structure. — The walls of the capillaries consist of a fine, transparent, homo-
geneous membrane, in which are embedded, at intervals, minute oval corpuscles.
When stained with nitrate of silver, the edges which bound the epithelial cells
are brought into view (Fig. 4:5). These cells are of large size, of an irregular
polygonal or fusiform shape, each containing one of the nuclei seen before the
application of the reagent. The whole capillary wall seems formed of these cells.
Between their edges, at various points of their meeting, roundish dark spots are
sometimes seen, which have been described as storaata, and have been believed
to be the mechanism by which fluid transudes from and possibly into the vessel.
But this view, though probable, is not universally accepted.
In many situations a delicate sheath or envelope of fine connective tissue is
found around the simple capillary tube ; and in other ]ilaces, especially in the
glands, the capillaries arc invested with retiform lymphatic tissue. •
In the largest ca])illarics (whicli origlit perhaps to be described rather as the
smallest arteries) traces of an epithelial lining and of circular transverse fibres
arc to be seen.
Veins arc composed of three coats, internal, middle, and external, as the
arteries are ; and these coats are, with the necessary modifications, analogous to
THE VEINS.
79
Capillaries from the
mesentery of a guinea-pig
after treatment witii solu-
tion of nitrate of silver.
a, cells, b, their nuclei.
the coats of the arteries — the internal being the epithelial, Fig. 45.
the middle the fibrous, and the external the connective or
areolar. The main difference between the veins and the
arteries is in the comparative weakness. of the middle coat
of the former ; and to this it is due that the veins do not
stand open when divided, as the arteries do ; and that they
are passive rather than active organs of the circulation.
In the veins immediately above the capillaries the three
coats are hardly to be distinguished. The epithelium is
supported on an outer membrane of nucleated connective
tissue, separable into two layers, the outer of which is the
thicker, the fibres of both being longitudinal. The interior
thinner layer of nucleated tissue is regarded by Kolliker
as the analogue of the middle coat. In the veins next
above these in size (one-fifth of a line, according to Kolli-
ker) a muscular layer and a layer of circular fibres can be
traced, forming the middle coat, while the elastic and con-
nective elements of the outer coat become more distinctly
perceptible.
In the middle-sized veins, the typical structure of these
vessels becomes clear. The epithelium is of the same
character as in the arteries, but its cells are more oval, less
fusiform. It is supported by one or more layers of nu-
cleated fibrous tissue, arranged longitudinally, and external
to this is a layer of elastic fibrous tissue. This constitutes the internal coat.
The middle coat is composed of a thick inner layer of connective tissue with
elastic fibres, having intermixed in some veins a transverse layer of muscular
fibres ; and an outer layer consisting of longitudinal elastic lamellae, varying
from iive to ten in number, alternating with layers of transverse muscular fibres
and connective tissue, which resembles somewhat in structure the middle coat
of large arteries. The outer coat is similar in all essential respects to that of
the arteries. In the large veins, as in the commencement of the vena portee, in
the upper part of the abdominal portion of the inferior vena cava, and in the
large hepatic trunks within the liver, the middle coat is thick, and its structure
similar to that of the middle coat in medium-sized veins ; but its muscular tissue
is scanty, and the longitudinal elastic networks less distinctly lamellated. The
muscular tissue of this coat is best marked in the splenic and portal veins ; it is
absent in certain parts of the vena cava below the liver, and wanting in the
subclavian vein and terminal parts of the two cava.
In the largest veins the outer coat is from two to five times thicker than the
middle coat, and contains a large number of longitudinal muscular fibres. This
is most distinct in the hepatic part of the inferior vena cava, and at the termina-
tion of this vein in the heart ; in the trunks of the hepatic veins ; in all the
large trunks of the vena portee ; in the splenic, superior mesenteric, external
iliac, renal, and azygos veins. Where the middle coat is absent, this muscular
layer extends as far as the inner coat. In the renal and portal veins, it extends
through the whole thickness of the outer coat ; but in the other veins mentioned
a layer of connective and elastic tissues is found external to the muscular fibres.
All the large veins which open into the heart are covered for a short distance
by a layer of striped muscular tissue continued on to them from the heart.
Muscular tissue is wanting in the veins — 1. Of the maternal part of the pla-
centa. 2. In most of the cerebral veins and sinuses of the dura mater. 3. In
the veins of the retina. 4. In the veins of the cancellous tissue of bones. 5. In
the venous spaces of the corpora cavernosa. The veins of the above-mentioned
parts consist of an internal epithelial lining, supported on one or more layers of
areolar tissue.
Most veins are provided with valves, which serve to prevent the reflux of the
80
GENERAL ANATOMY.
blood. They are formed by a reduplication of the inner and part of the middle
coat, and consist of connective tissue and elastic fibres, covered on both surfaces
by epithelium ; their form is semilunar. They are attached by their convex
edge to the wall of the vein ; the concave margin is free, directed in the course
Fisr. 46.
Fig. 47.
1 ^ '^
mmmSi,
'mm
p'
Finest vessels on the arterial side. 1, smallest artery. An artery, .01"', and b, a vein, .015", from the
2, transition vessel. 3, coarser capillaries. 4, finer mesentery of a child, magnified 350 Times, and
capillaries, a, structureless membrane still with some treated with acetic acid. The letters as in
nuclei, representative of the tunica adventitia ; 6, nuclei Fig. 44. e, the tunica media of the vein, con-
of the muscular fibre-cells ; c, nuclei within the small sisting of nucleated connective tissue,
artery, perhaps appertaining to an epithelium ; d, nuclei
in the transition vessels. From the human brain.
(Magnified 300 times.)
of the venous current, and lies in close apposition with the wall of the vein as
long as the current of blood takes its natural course ; if, however, any regurgi-
tation takes place, the valves become distended, their opposed edges are brought
into contact, and the current is intercepted. Most commonly two such valves
are found, placed opposite one another, more especially in the smaller veins, or
in the larger trunks at the point where they are joined by small branches ; oc-
casionally there are three, and sometimes only one. The wall of the vein
immediately above the point of attachment of each segment of the valve is ex-
])andcd into a pouch or sinus, which gives to the vessel, when injected or dis-
tended with blood, a knotted appearance. The valves are very numerous in
the veins of the extremities, especially of the lower extremities, these vessels
having to conduct the blood against the force of gravity. They are absent in
tlie very small veins, also in the venas cavce, the hepatic vein, portal vein and
its branches, the renal, uterine, and ovarian veins. A few valves are found in
the spermatic veins, and one also at their point of junction with the renal vein
and inferior cava in both sexes. The cerebral and spinal veins, the veins of the
cancellated tissue of bone, the ]')ulmonary veins, and the umbilical vein and its
branches, are also destitute of valves. They are occasionally found, few in num-
ber, in the venae azygos and intercostal veins.
The veins are supplied Avith nutrient vessels, vasn vasornm, like the arteries ;
but nerves arc not generally found distributed upon them. The only vessels
THE LYMPHATICS,
81
upon wliich. they liave at present been traced are tlie sinuses of tlie dura mater ;
on the spinal veins ; on the venas cavaB ; on the common jugular, iliac, and cru-
ral veins ; and on the hepatic veins (Kolliker)
Fiff. 48.
Transverse section throuQ;h the coats
of the thoracic duct of man. (Magni-
fied 30 times.) a, Epithelium, striated
lamellae, and inner elastic coat; b, lon-
gitudinal connective tissue of the mid-
dle coat; c, transverse muscles of the
same ; d, tunica adventitia, with e, the
longitudinal muscular libres.
The Lymphatic Vessels^ like arteries and veins, are composed of three coats.
The internal is an epithelial and elastic coat. It is thin, transparent, slightly
elastic, and ruptures sooner than the other coats. It is composed of a layer of
elongated epithelial cells, supported on a simple network of elastic fibres. The
middle coat is composed of smooth muscular and fine elastic fibres, disposed in
a transverse direction. The external, or areolar-fibrous coat, consists of fila-
ments of the areolar tissue, intermixed with smooth muscular fibres, longitudi-
nally or obliquely disposed. It forms a protective covering to the other coats,
and serves to connect the vessel with the neighboring structures.
The lymphatics are supplied by nutrient vessels, which are distributed to their
outer and middle coats ; but no nerves have at present been traced into them.
The lymphatics are very generally provided with valves, which assist mate-
rially in effecting the circulation of the fluid they
contain. These valves are formed of a thin layer
of fibrous tissue, lined on both surfaces with scaly
epithelium. Their form is semilunar, they are
attached by their convex edge to the sides of the
vessel, the concave ed2;e beino- free, and directed
along the course of the contained current. Usu-
ally, two such valves, of equal size, are found op-
posite one another ; but occasionally exceptions
occur, especially at or near the anastomoses of
lymphatic vessels. Thus one valve may be of
very rudimentary size, and the other increased in
proportion. In other cases, the semilunar flaps
have been found directed transversely across the
vessel, instead of obliquely, so as to impede the
circulation in both directions, but not to completely arrest it in either ; or the
semilunar flaps, taking the same direction, have been found united on one side, so
as to form, by their union, a transverse septum, having a partial transverse slit ;
and sometimes the flap is constituted of a circular fold, attached to the entire
circumference of the vessel, and having in its centre a circular or elliptical aper-
ture, like the ileo-caecal valve.
The valves in the lymphatic vessels are placed at much shorter intervals than
in the veins. They are most numerous near the lymphatic glands, and they are
found more frequently in the lymphatics of the neck and upper extremity
than in the lower. The wall of the lymphatics, immediately above the point of
attachment of each segment of a valve, is expanded into a pouch or sinus, which
gives to these vessels, when distended, the knotted or beaded appearances which
they present. Yalves are wanting in the vessels composing the plexiform net-
work in which the lymphatics usually originate on the surface of the body.
The finest visible lymphatic vessels form a plexiform network in the subcu-
taneous and submucous tissues, and this is properly regarded as one method of
their commencement. But the lymphatics have also other modes of origin, for
the intestinal lacteals commence by closed extremities (Fig. 438), and it seems
now to be conclusively proved that the serous membranes present stomata, or
openings between the epithelial cells, by which there is an open communication
with the lymphatic system, and through which the lymph is thought to be
pumped by the alternate dilatation and contraction of the serous surface, due to
the movements of respiration and circulation.^ Von Eecklinghausen was the
' The resemblance between lymph and serum led Hewson lonGr ago to regard the serons cavities
as sacs into which the b'mphatics open. These recent microscopic discoveries confirm this opinion
in a very interesting manner.
6
82
GENERAL ANATOMY.
1, epithelium from the under surface
of the centrum tendineum of the rabbit ;
a, pores. 2, epithelium of the medias-
tinum of tlie dos ; a, i)ores, 3, section
through the pleura of the same ani-
mal; 6, free orifices of short lateral
passages of the lymph canals (copied
from Liudvvig, Schweigger-Seydel, and
Dybkowsky).
first to observe tlie passage of milk and other
colored fluid tlirougli tliese stomata on tlie perito-
neal surface of the central tendon of the diaphragm.^
Again, the lymphoid or retiform tissue which is
found in various organs, and in some, as in the
spleen, surrounds the minute bloodvessels with a
kind of sheath, forms another and a very exten-
sive mode of origin of lymphatics, whether the
meshes of this retiform tissue pass directly into the
minute lymphatic plexus, or whether the latter is
regarded as closed, so that the fluid in the retiform
tissue has to pass by osmosis into the lymphatic
vessel, which certainly seems to be the case in the
intestinal villi. As the retiform tissue is also in
very similar relation to the terminal capillaries,
there is here a free method of communication be-
tween the bloodvessels and lymphatics, though the
direct continuity of their tubes by vascular anas-
tomosis can nowhere be proved to exist, as far as
has been shown at present. The lymph-sinuses or
lym'ph-'patlis of the lymphatic glands may be re-
garded as another mode of origin of lymphatics, or
as a modification of the above-mentioned origin in
retiform tissue.
There is no satisfactory evidence to prove that
any natural communication exists between the
lymphatics of glandular organs and their ducts.
The Lymphatic Glands consist of (1) a fibrous
envelope, or capsule^ from which a framework of
processes {traheculse) proceeds inwards, dividing the
gland into open spaces {alveoli) freely communicating with each other ; (2) a large
quantity of retiform connective tissue occupying these spaces ; (3) a free supply
of bloodvessels, which are supported on
the trabeculfe ; and (4) the afferent and
efferent lymphatics. Little is known of
the nerves, though Kolliker describes
some fine nervous filaments passing into
the hilum.
The afferent lymphatics enter the
capsule of the gland in variable num-
bers and at various points, while the
efi'erent vessels are usually only one or
two, and they emerge from the gland at
a definite spot, the hilum, where there
is usually, but not always, a recogniza-
ble depression. The external coats of
tlie lympliatic vessels are continuous
witli the capsule of the gland ; their
internal epithelial lining is continuous
with that of the lymph-channel in the
interior of the gland.
A section of a lymphatic gland dis-
plays tAvo difi'eront structures: an ex-
ternal of lighter color — the cortical; and
Section of small lymphatic gland, half diagram-
matioally given, with the course of the lymph, a,
the envelope ; 6, septa between the follicles or alve-
oli of the cortical part; c, system of septa of the
medullary portion, down to the hilum ; d, the folU-
cles; e, lymph-tubes of the medullary mass;/, difTer-
ont )yini)l)atio streams which surround the follicles,
and flow through the interstices of the medullary
jiortioii ; g, confluence of these, passing through the
efferent vessel, li, at the hilum.
' For a fuller account sec Klein's "Anatomy of the Lymphatic .System."
THE SKIN.
83
an internal, darker — the medullary. In the cortical the retiform tissue is dis-
posed in the form of follicles or nodules, which are held on to the septa by
delicate sustentacular fibres, which unite them to the trabeculse, and are said
by Frey to keep them stretched and open, as a piece of embroidery is stretched
to its frame. From these nodules rods or tubes of retiform tissue proceed,
which interlace with each other in a very minute network, of which the
medullary tissue of the gland is formed. These rods, equally with the nodules
of the cortical portion, are supported by a delicate connective tissue which
"attaches them to the trabecule, and which also contains lymphoid corpuscles,
though in less quantity than in the nodules and rods of the gland-pulp.
Fig-. 51.
Fiff. 52.
^:?Z
x
111
'\)w^
• ' III,
-x-/i
From the medullary substance of an
inguinal gland of the ox (after His), a.
Lymph-tube, with its complicated system
of vessels; 6, retinacula stretched be-
tween the tube and the septa ;c, portion
of another lymph-tube ; d, septa.
Follicle from a lymphatic gland of the dog, in vertical section.
a. Reticular sustentacular substance of the more external por-
tion; 6, of the more internal, and c, of the most external and
most finely-webbed part on the surface of the follicle ; d, origin
of a large lymph-tube ; e, of a smaller one ; /, capsule ; g, septa ;
h, vas afferens ; i, investing space of the follicle, with its reti-
nacula; k, one of the divisions of the septa; II, attachment of
the lymph-tubes to the septa.
The afferent lymphatics open directly into the sustentacular tissue around
the nodes and rods — the lymph-path or lymph-channel. This investing space
is continuous over both the nodules of the cortical, and the rods or tubes of the
medullary, portion, and the efferent lymphatics are continuous with it in the
latter portion of the gland.
The rods of the medullary part are described by Frey as forming a lymphoid
sheath for the capillary vessels which run in the axis' of the retiform tissue,
while other branches are distributed in a rich network over it (Fig. 52). It is
doubtless in these spaces that the exchange of materials goes on between the
bloodvessels and the lymphatics which is necessary to the further elaboration
of the lymph and the multiplication of the lymph-corpuscles which takes place
in the glands (see page 38).
THE SKIN AND ITS APPENDAGES.
The Skin is the principal seat of the sense of touch, and may be regarded as
a covering for the protection of the deeper tissues; it is also an important
excretory and absorbing organ. It consists of two layers, the derma or cutis
84
GENERAL ANATOMY
vera, and the epidermis or cuticle. On the surface of the former layer are the
sensitive pa]3ill£e; and within, or embedded beneath it, are the sweat-glands,
hair-follicles, and sebaceous glands.
The derma^ or true skin^ is tough, flexible, and highly elastic, in order to
defend the internal parts from violence. It consists of fibro-areolar tissue, inter-
Fig. 53.
A Sectional View of the Skin (magnified).
mixed with numerous bloodvessels, lymjDhatics, and nerves. The fibro-areolar
tissue forms the framework of the cutis; it is composed of firm interlacing
bundles of white fibrous tissue, intermixed with a much smaller proportion of
yellow elastic fibres, the amount of which varies in different parts. The fibro-
areolar tissue is more abundant in the deeper layers of the cutis, where it is
dense and firm, the meshes being large, and gradually becoming blended with
the subcutaneous areolar tissue; towards the surface, the fibres become finer
and more closely interlaced, the most superficial layer being covered with
numerous small conical vascular eminences, the papilhe. From these difl'erences
in the structure of the cutis at different parts, it is usual to describe it as con-
sisting of two layers: the deeper layer or corium, and the superficial or papillary
layer.
The corium consists of strong interlacing fibrous bands, composed chiefly of
the white variety of fibrous tissue ; but containing, also, some fibres of the yel-
low elastic tissue, which vary in amount in different parts. Towards the
attached surface, the fasciculi are large and coarse; and the areolae which arc
left by their interlacement arc large, and occupied by adipose tissue and the
sweat-glands. This element of the skin becomes gradually blended with the sub-
cutaneous areolar tissue. Towards the free surface, the fasciculi are much
THE SKIN. 85
finer, and they have a close interlacing, the most superficial layers consisting of
a transparent, homogeneous 'matrix, with embedded nuclei.
The corium varies in thickness, from a quarter of a line to a line and a half,
in different parts of the body. Thus, it is thicker in the regions exposed to
pressure, as the palm of the hand and sole of the foot ; thicker on the posterior
aspect of the body, than the front ; and on the outer, than the inner side of the
limbs. In the eyelids, scrotum, and penis, it is exceedingly thin and delicate.
The skin generally is thicker in the male than in the female, and in the adult
than in the child.
The areolae are occupied by adipose tissue, hair-follicles, and the sudoriferous
and sebaceous glands ; they are the channels by which the vessels and nerves
are distributed to the more superficial strata of the corium, and to the papillary
layer.
Unstriped muscular fibres are found in the superficial layers of the corium,
wherever hairs are found ; and in the subcutaneous areolar tissue of the scrotum,
penis, peringeum, and areolae of the nipples. In the latter situations the fibres
are arranged in bands, closely reticulated and disposed in superimposed laminaa.
The paijillary layer is situated upon the free surface of the corium ; it consists
of numerous small, highly sensitive, and vascular eminences, the papillse, which
rise perpendicularly from its surface, and form the essential element of the organ
of touch. The papilla3 are conical-shaped eminences, having a round or blunted
extremity, occasionally divided into two or more parts, and connected by their
base with the free surface of the corium. Their average length is about y^oth
of an inch, and they measure at their base about ^In'tli ^^ ^^ inoh in diameter.
On the general surface of the body, more especially in those parts which are
endowed with slight sensibility, they are few in number, short, exceedingly
minute, and irregularly scattered over the surface ; but in other situations, as
upon the palmar surface of the hands and fingers, upon the plantar surface of
the feet and toes, and around the nipple, they are long, of large size, closely
aggregated together, and arranged in parallel curved lines, forming the elevated
ridges seen on the free surface of the epidermis. In these ridges, the larger
papillas are arranged in a double row, with smaller papillse between them ; and
these rows are subdivided into small square- shaped masses by short transverse
furrows, regularly disposed, in the centre of each of which is the minute orifice
of the duct of a sweat-gland. ISTo papillse exist in the grooves between the
ridges. In structure, the papillge resemble the superficial layer of the cutis ;
consisting of a homogeneous tissue, faintly fibrillated, and containing a few fine
elastic fibres. The smaller papillae contain a single capillary loop ; but in the
larger the vessels are convoluted to a greater or less degree ; each papilla also
contains one or more nerve- fibres, but the mode in which these terminate is un-
certain. In those parts in which the sense of touch is highly developed, as in
the lips and palm of the hand, the nerve-fibres are connected with the "tactile
corpuscles," Kcilliker considers that the central part of the papillse generally
consists of a connective tissue more homogeneous than that of the outer part,
surrounded by a sort of sheath of elastic fibres, and he believes that these cor-
puscles are merely a variety of this structure. The corpuscles, and their con-
nection with the nerves, have been described above.
The epidermis^ or cuticle (scarf-skin), is an epithelial structure, accurately
moulded on the papillary layer of the derma. It forms a defensive covering to
the surface of the true skin, and limits the evaporation of watery vapor from its
free surface. It varies in thickness in different parts. Where it is exposed to
pressure and the influence of the atmosphere, as upon the palms of the hands
and soles of the feet, it is thick, hard, and horny in texture ; whilst that which
lies in contact with the rest of the body is soft and cellular in structure. The
deeper and softer layeys have been called the rete mucostim, the term rete being
used from the deepest layers presenting, when isolated, numerous depressions,
or complete apertures, which have been occupied by the projecting papillse.
86 GENERAL ANATOMY.
Tlie free surface of the epidermis is marked by a network of linear farrows of
variable size, marking out tlie surface into a number of spaces of polygonal or
lozenge-shaped form. Some of these furrows are large, as opposite the flexures
of the joints, and correspond to the folds in the derma produced by their move-
ments. In other situations, as upon the back of the hand, they are exceedingly
fine, and intersect one another at various angles : upon the palmar surface of
the hand and fingers, and upon the sole, these lines are very distinct, and are
disposed in curves. They depend upon the large size and peculiar arrangement
of the papillae upon which the epidermis is placed. The deep surface of the
epidermis is accurately moulded upon the papillary layer of the derma, each
papilla being invested by its epidermic sheath ; so that when this layer is re-
moved by maceration, it presents a number of pits or depressions corresponding
to the elevations of the papillse, as well as the furrows left in the intervals be-
tween them. Fine tubular prolongations from this layer are continued into the
ducts of the sudoriferous and sebaceous glands. In structure, the epidermis
consists of flattened cells, agglutinated together, and having a laminated arrange-
ment. In the deeper layers the cells are large, rounded or columnar, and filled
with soft opaque contents. In the superficial layers the cells are flattened,
transparent, dry, and firm, and their contents converted into a kind of horny
matter. The difference in the structure of these layers is dependent upon the
mode of growth of the epidermis. As the external layers desquamate from
their being constantly subjected to attrition, they are reproduced from beneath,
successive layers gradually approaching towards the free surface, which, in their
turn, die and are cast off.
These cells are developed in the liquor sanguinis, which is poured out on the
free surface of the derma ; they contain nuclei, and form a thin stratum of
closely-aggregated nucleated cells, which cover the entire extent of the papil-
lary layer. The deepest layers of cells, according to KoUiker, are of a columnar
form, and are arranged perpendicularly to the free surface of the derma, form-
ing either a single or a double, or even triple, layer ; the laminae succeeding
these are composed of cells of a more rounded form, the contents of which are
soft, opaque, granular, and soluble in acetic acid. As these cells succesively
approach the surface by the development of fresh layers from beneath, they
assume a flattened form from the evaporation of their fluid contents, and finally
form a transparent, dry, membranous scale, lose their nuclei, and ajDparently
become changed in their chemical composition, as they are unaffected now by
acetic acid.
The black color of the skin in the negro, and the tawny color among some of
the white races, is due to the presence of pigment in the cells of the cuticle.
This pigment is more especially distinct in the cells of the deeper layer, or rete
mucosum, and is similar to that found in the choroid. As the cells approach
the surface and desiccate, the color becomes partially lost.
The arteries which supply the skin divide into numerous branches in the sub-
cutaneous tissue ; they then pass through the areolae of the corium, and divide
into a dense capillary plexus, which supplies the sudoriferous and sebaceous
glands and the hair-follicles, terminating in the superficial layers of the corium,
by forming a capillary network, from which numerous fine branches ascend to
the papillte.
The h/mphatic vessels are arranged in a minute plexiform network in the
superficial layers of the corium, where they become interwoven with the capil-
lary and nervous plexuses ; they are especially abundant in the scrotum and
around the nipple.
The nerves which sn])i)ly tlu; skin ascend with the vessels through the areolae
of the deep layers of the corium to the more superficial layers, where they form
a minute plexiform mesh. From this plexus, the primitive nerve-fibres pass to
be distributed to the papillae. I^lic nerves are most numerous in those parts
which are provided with the greatest sensibility.
THE SKIN. 87
Tlie appendages of tlie skin are, tlie nails, tlie liairs, tlie sucloriferons and
sebaceous glands, and tlieir ducts. The nails and liairs are peculiar modifica-
tions of the epidermis, consisting essentially of the same cellular structure as
that membrane.
The Nails are flattened elastic structures of a horny texture, placed upon the
dorsal surface of the terminal phalanges of the fingers and toes. Each nail is
convex on its outer surface, concave within, and is implanted by a portion called
the root into a groove of the skin ; the exposed portion is called the hody^ and the
anterior extremity the free edge. The nail has a very firm adhesion to the cutis,
being accurately moulded upon its surface, as the epidermis is in other parts.
The part of the cutis beneath the body and root of the nail, is called the matrix^
because it is the part from which the nail is produced. Corresponding to the
body of the nail, the matrix is thick, and covered with large, highly vascular
papillas, arranged in longitudinal rows, the color of which is seen through the
transparent tissue. Behind this, near the root of the nail, the papillse are small,
less vascular, and have no regular arrangement ; hence, the portion of the nail
corresponding to this part is of a whiter color, and called lunula^ from its form.
The cuticle, as it passes forwards on the dorsal surface of the finger, is attached
to the surface of the nail, a little in advance of its root : at the extremity of the
finger, it is connected with the under surface of the nail, a little behind its free
edge. The cuticle and horny structure of the nail (both epidermic structures)
are thus directly continuous with each other. The nails, in structure, consist of
cells having a laminated arrangement, and these are essentially similar to those
composing the epidermis. The cells of the deepest layer which lie in contact
A^ith the papillee at the root and under surface of the nail, are of elongated form,
arranged perpendicularly to the surface, and provided with nuclei ; those which
succeed these are of a rounded or polygonal form, the more superficial ones
becoming broad, thin, and flattened, and so closely compacted together as to
make the limits of each cell very indistinct.
It is by the successive growth of new cells at the root and under surface of
the body of the nail, that it advances forwards, and maintains a due thickness,
whilst, at the same time, the growth of the nail in the proper direction is secured.
As these cells in their turn become displaced by the growth of new cells, they
assume a flattened form, lose their nuclei, and finally become closely compacted
together into a firm, dense horny texture. In chemical composition^ the nails
resemble the epidermis. According to Mulder, they contain a somewhat larger
proportion of carbon and sulphur.
The Hairs are peculiar modifications of the epidermis, and consist essentially
of the same structure as that membrane. They are found on nearly every part
of the surface of the body, excepting the palms of the hands and soles of the
feet, and vary much in length, thickness, and color in different parts of the body
and in different races of mankind. In some parts they are so short as not to
project beyond the follicles containing them ; in other parts, as upon the scalp,
they are of considerable length ; along the margin of the eyelids and upon the
face, they are remarkable for their thickness. A hair consists of a root^ the
part implanted in the skin ; the shaft^ the portion projecting from its surface,
and the point. They generally present a cylindrical or more or less flattened
form, and a reniform outline upon a transverse section (Fig. ,54).
The root of the hair presents at its extremity a bulbous enlargement, which is
whiter in color, and softer in texture, than the stem, and is lodged in a follicular
involution of the epidermis, called the hairfollicle. When the hair is of con-
siderable length, the follicle extends into the subcutaneous cellular tissue. The
hair follicle is bulbous at its deep extremity, like the hair which it contains, and
has opening into it, near its free extremity, the orifices of the ducts of one or
more sebaceous glands. In structure, the hair-follicle consists of two coats : an
outer or dermic, and an inner or cuticular. The outer coat is formed mainly of
areolar tissue ; it is continuous with the corium, is highly vascular, and supplied
GENERAL ANATOMY.
fibrils: this is the part tlirougli which, material
is supplied for the production and constant
growth of the hair. The root of the hair rests
upon this conical -shaped eminence, and is con-
tinuous with the cuticular lining of the follicle
at this part. It consists of nucleated cells, simi-
Y respect to those whi
These cells
by numerous minute nervous filaments. The
inner or cuticular lining is continuous with the
epidermis, and, at the bottom of the hair-follicle,
with the root of the hair ; this cuticular lining-
resembles the epidermis in the peculiar rounded
form and soft character of those cells which lie
in contact with the outer coat of the hair-follicle,
and the thin, dry, and scaly character of those
which lie near the surfece of the hair, to which
they are closely adherent. When the hair is
plucked from its follicle, the cuticular lining-
most commonly adheres to it, and forms what is
called the root-sheath. At the bottom of each
hair-follicle is a small conical vascular eminence
or papilla, similar in every respect to those found
upon the surface of the skin ; it is continuous
Diagram of structure of hair, iiair witli the clermic layer of the foUiclc, is highly
foiiicie,and sebaceous glands (Koiiiker). vascular, and probably Supplied with nervous
a. Root of hair, in its follicle. 1. Outer -- - .... . _ _ _ _ _
dry layer of cuticle. 2. iMalpighian or
mucous layer, both dipping into hair
sac. 3. Cutis, or true skin. 4. Sebaceous
glands, opening into hair sac. 5. Root
of hair. 6. Walls of hair sac. 7. Papilla,
on which hair grows, b. Larger view
of lower end of root of hair, and bottom
of hair sac. 6. Hair sac, showing outer ]g^p j^^ eVCry rCSpCCt tO thoSC which iu Othcr
and inner root-sheath, latter adhering ., ,• n ^ ,-i • -< ■ rm n
to hair. 7. Vascular papilla on which Situations form the epidermis. These cells
hair grows. The hair itself shows its gradually enlarge as they are pushed upwards
nbrous structure, its dark medulla, and into the soft bulb, and somc of them contaiu
transverse lines of its scaly covering, pigment-grauules, wMch either exist in Separated
c. Transverse section of a hair, snowing -i o c) i i
its outer covering, its fibrous part, and cclls, OT are Separate, OT aggregated rouiid the
central softer medulla or pith.] nUclcUS ; it is thcSC grauulcs which givC risC tO
the color of the hair. It occasionally happens
that these pigment-granules completely fill the cells in the centre of the bulb,
which gives rise to the dark tract of pigment often found, of greater or less length,
in the axis of the hair.
The shaft of the hair consists of a central part or medulla, the fibrous part of
the hair, and the cortex externally. The medulla occupies the centre of the
shaft, and ceases towards the point of the hair. It is usually wanting in the fine
hairs covering the surface of the bod}^, and commonly in those of the head. It
is more opaque and deeper colored than the fibrous part, and consists of cells
containing pigment- or fat-granules. The fibrous portion of the hair constitutes
the chief part of the stem ; its cells are elongated, and unite to form flattened
fusiform fibres. These also contain pigment-granules, which assume a linear
arrangement. The cells which form the cortex of the hair consist of a single
layer which surrounds those of the fibrous part ; they are converted into thin
flat scales, having an imbricated arrangement.
Tlie Sehaceons Gkmds are small, sacculated, glandular organs, lodged in the
substance of the corium, or subdermoid tissue. They arc found in most parts
of the skin, but arc most abundant in the scalp and face ; they are also very
numerous around the apertures of the anus, nose, mouth, and external ear ; but
are wanting in the palms of the hands and soles of the feet. Each gland consists
of a single duct, more or less capacious, which terminates in a lobulated pouch-
like extremity. The basement membrane forming the wall of the sac, as Avell
as the duct, is lined by epithelium, which is filled with particles of sebaceous
matter; and this becoming detached into the cavity of the sac, as its growth is
renewed, constitutes the secretion. The sacculi connected with each duct vary
in number from two to five, or even twenty. The orifices of the ducts open
SUDORIFEROUS GLANDS.
89
most frequently into tlie hair-follicles, but occasionally upon tlie general surface.
On the nose and face, the glands are of large size, distinctly lobnlated, and often
become mnch enlarged from the accumnlation of pent-up secretion. The
largest sebaceous glands are those found in the eyelids, the Meibomian glands.
The Sudoriferous or Siveat- glands are the organs by which a large portion of
the aqueous and gaseous materials are excreted by the skin. They are found in
almost every part of the skin, and are situated in
small pits in the dee|3 parts of the corium, or, more
frequentl}^, in the subcutaneous areolar tissue, sur-
rounded by a quantity of adipose tissue. They
are small, lobular, reddish bodies, consisting of one
or more convoluted tubuli, from which the efferent
duct proceeds upwards through the corium and
cuticle, and opens upon the surface by a slightly
enlarged oriiice. The efferent duct, as it passes
through the corium, pursues for a short distance,
a spiral course : it becomes straight in the more
superficial part of this layer, and opens on the sur-
face of the cuticle by an oblique valve-like aperture.
In the parts where the epidermis is thin, the ducts
are finer, and almost straight in their course ; but
where the epidermis is thicker, they assume again
a spiral arrangement, the separate windings o'f the
tube being as close and as regular as those of a
common screw. The spiral course of these ducts is
especially distinct in the thick cuticle of the palm
of the hand and sole of the foot. (Fig. 55.) The
size of the glands varies. They are especially large
in those regions where the amount of perspiration
is great, as in the axillse, where they form a thin
mammillated layer of a reddish color, which corre-
sponds exactly to the situation of the hair in this
region ; they are large, also, in the groin. Their
number varies. They are most numerous on the
palm of the hand, presenting, according to Krause,
2800 orifices on a square inch of the integument,
and are rather less numerous on the sole of the foot.
In both of these situations, the orifices of the ducts
are exceedingly regular, and correspond to the
small transverse grooves which intersect the ridges
of papillse. In other situations they are more
irregularly scattered, but in nearly equal numbers,
over parts including the same extent of surface. In
the neck and back they are least numerous, their
number amounting to 417 on the square inch
(Krause). Their total number is estimated by the
same writer at 2,381,248 ; and, supposing the aper-
ture of each gland to represent a surface of 5^5 th of
a line in diameter, he calculates that the whole of
these glands would present an evaporating surface of about eight square inches.
Each gland consists of a single tube intricately convoluted, terminating at one
end by a blind extremity, and opening at the other end upon the surface of the
skin. In the larger glands this single duct usually divides and subdivides
dichotomously ; the smaller ducts ultimately terminating in short ca3cal
pouches, rarely anastomosing. The wall of the duct is thick ; the width of the
canal rarely exceeding one-third of its diameter. The tube, both in the gland
and where it forms the excretory duct, consists of two layers : an outer, formed
Sudoriferous Gland from the
palm of the hand, magnified 40
diam.: 1, 1, contorted tubes com-
posing the gland and uniting in two
excretory ducts, 2, 2, which unite
into one spiral canal that perforates
the epidermis at 3, and opens on
its surface at 4 ; the gland is im-
bedded in fat-vesicles which are
seen at 5, 5]
90
GENERAL ANATOMY.
by fine areolar tissue ; and an inner layer of epitlielinm. The external, or fibro-
cellular coat, is tliin, continuous with the superficial layer of the corium, and
extends only as high as the surface of the true skin. The epithelial lining is
much thicker, continuous with the epidermis, and alone forms the spiral portion
of the tube. When the cuticle is carefully removed from the surface of the
cutis, these convoluted tubes of epidermis may be drawn out, and form nipple-
shaped projections on its under surface. According to Kolliker, a layer of non-
striated muscular fibres, arranged longitudinally, is found between the areolar
and epithelial coats of the ducts of the larger sweat-glands, as in the axilla, root
of the penis, on the labia majora, and round the anus.
The contents of the smaller sweat-glands are quite fluid; but in the larger
glands, the contents are semi-fluid and opaque, and contain a number of colored
granules, and cells which appear analogous to epithelial cells.
THE EPITHELIUM.
All the surfaces of the body, the external surface of the skin, the internal sur-
face of the digestive and respiratory tracts, the closed serous cavities, the inner
coat of the vessels, and the ducts of all glands, are covered by one or more layers
of simple cells, called epithelium or epithelial cells, which serve various pur-
poses, both as a protective layer, and as an agent in secretion. Thus, in the
skin, the main purpose served by the epithelium (here called the epidermis) is
that of protection. As the surface is worn away by the agency of friction or
change of temperature, new cells are supplied, and thus the surface of the true
skin, and the vessels and nerves which it contains, are defended from damage.
In the gastro-intestinal mucous membrane and in the glands, the epithelial cells
appear to be the principal agents in separating the secretion from the blood or
from the alimentary fluids. In other situations (as the nose, fauces, and respira-
tory passages) the chief office of the epithelial cells appears to be to maintain an
equable temperature by the moisture with which they keep the surface always
slightly lubricated. In the serous cavities they also keep the opposed layers
moist, and thus facilitate their movements on each other. Finally, in all internal
parts they ensure a perfectly smooth surface.
Fig. 56.
Epithelinl cells in the oral cavity of man. a, larsfp. b, middle-slr.pd. c, tlie game with two nuclei. CMagnl-
fled 3&0 lirnoH.)
TliC epithelium is usually spoken of as tcsselated or ]-)avcmcnt, columnar,
spheroidal or glandular, and ciliated.
Tiie pavemf'.nt-Ci]-)iihcVmm is composed of flat nucleated scales of various shapes,
usually polygonal, and varying in si/e. Tliese scales often contain granules, as
in Fig. 56.' This kind of epithelium is found on the surface of the skin (epi-
dermis), on all the serous surfaces (unless the ventricles of the brain be an
ex-
THE EPITHELIUM.
91
ception), on tlie lining membranes of the bloodvessels,^ on many of the mucous
membranes, and in the ducts. The nails, hairs, and in animals the horns, are a
variety of this kind of epithelium.
[Fig. 57.
Fig. .08.
,ji>^^-^^
Tessellated epithelium from the abdominal surface Epithelium of the inestinal villi of the rabbit.
of centrum tendinum of rabbit, strongly colored with a, basement-menibraue. (Magnified 300 times.;
nitrate of silver ; a, dark silver lines of the interstitial
substance of the endothelial cells; b, cell-substance ; c,
nucleus. The smaller cells lie over a capillary lym-
l)hatic.]
The columnar epithelium (Fig. 58) is formed of cylindrical or rod-shaped cells,
each containing a nucleus, and set together, so as to form a complete membrane.
This form of epithelium covers the mucous membrane of the whole gastro-
intestinal tract and the glands of that part, the greater part of the urethra, the
vas deferens, the prostate, Cowper's glands, Bartholine's glands, and a portion
of the uterine mucous membrane.
The spheroidal or glandular epithelium (Fig. 59) is composed of circular cells,
with granular contents and a small nucleus.
This form is found in the kidney, ureters, and bladder, and in the secreting
glands.
Fiff. 59.
Fig. 60.
Spheroidal epithelium from the human blad- Oiliated epithelium from the human trachea. (Ma.a:ni-
der. (Magnified 250 times ) fied 350 times.) a, innermost layers of the elastic longi-
tudinal fibres, b, homogeneous innermost layers of the
mucous membrane, c, deepest round cells, d, middle
elongated, e, superficial, bearing cilia.
Ciliated epithelium (Fig. 60) may be of any of the preceding forms, but
usually inclines to the columnar shape. It is distinguished by the presence of
minute processes, like hairs or eyelashes (cilia), standing lip from the free sur-
face. If the cells be examined during life, or immediately on removal from the
As already stated, the epithelium linins" the bloodvessels, lymphatics, and serous membranes
IS modified in shape, and its cells vary much in size, It is usually spoken ol' in Gierman works as
e7idothelmm.
92 GENERAL ANATOMY.
living body (for'wliicli in tlie liuman subject the removal of a nasal polypus
offers a frequent opportunity), in tepid water, tbe cilia will be seen in active
lashing motion ; and if the cells be separate, they will often be moved about in
the field by that motion.
The situations in which ciliated epithelium is found in the human body are : the
respiratory tract from the nose downwards, the tympanum and Eustachian tube,
the Fallopian tube and upper portion of the uterus, and the ventricles of the brain.
SEROUS, SYNOVIAL, AND MUCOUS MEMBRANES.
These inembranes consist of a layer of epithelium supported on a structure-
less membrane, called the basement-membrane, beneath which lies a tract of
connective or areolar tissue, which in the mucous membranes lodges glands of
various kinds, and contains unstriped muscle, or contractile muscular fibre-cells,
and in both serous and mucous membranes conveys the bloodvessels out of which
the secretion is to be eliminated.
The serous membranes are the simplest of the three, and will therefore be first
described.
They form shut sacs, sometimes arranged quite simply, as the tunica vagi-
nalis testis, at others with numerous involutions and recesses, as the peritoneum,
bat which can always be traced continuously around the whole circumference.
The sac is completely closed, so that no communication exists between the serous
cavity and the parts in its neighborhood. An apparent exception exists in the
peritoneum of the female ; for the Fallopian tube opens freely into the peritoneal
cavity in the dead subject, so that a bristle can be passed from the one into the
other. But this communication is closed during life, except at the moment of
the passage of the ovum out of the ovary into the tube, as is proved by the fact
that no interchange of fluids ever takes place between the two cavities in dropsy
of the peritoneum, or in accumulation of fluid in the Fallopian tubes. The
serous membrane is often supported by a firm fibrous layer, as is the case with
the pericardium, and such membranes are sometimes spoken of as " fibro-serous."
In the parietal portion of the arachnoid there is, according to many anatomists,
no serous membrane in the proper sense of the term ; but the dura mater is
merely lined with a layer of epithelium, the basement-membrane being here indis-
tinguishable. In other situations, the following parts may be recognized as
constituting a serous membrane : — -1. The epithelium, a single layer of polygonal
or pavement-epithelial cells. 2. A structureless basement-membrane. 3. The
connective tissue and vessels which support the latter, connect it with the parts
below, and .supply blood to its deep surface. Some of the serous portion of the
blood is secreted, or transudes, through the basement-membrane to furnish the
special secretion. This latter is, in most cases, only in sufficient quantity to
moisten the membrane, but not to furnish any appreciable quantity of fluid.
When a small quantity can be collected, it appears to resemble in many respects
the lymph, and like that fluid coagulates spontaneously ; but when secreted in
large quantities, as in dropsy, it is a watery fluid containing usually sufficient
albumen to gelatinize with heat.
Lately the interesting discovery has been made that fluids with colored parti-
cles transude through the serous membrane into the lymphatic vessels, and
stomata or openings have been seen between the cells of the epithelium, which arc
believed to be opened and closed by the movements of the serous surface. These
stomata have been demonstrated at present only in the peritoneum and pleura.
The mjicous memhranes are more complex in their structure than the serous.
Their epithelium is of various forms, including the s])heroidal, columnar, and
ciliated, and is often arranged in several layers (see Fig. 60). This e}nthclial layer
is supported by the corium, which is analogous to the derma of the skin, and is
in fact continuous with it at the orifices of the body. The corium ccmsists, as it
SECRETIKG GLANDS. 93
is usually described, of a transparent structureless iDasement-membrane next to
tlie epithelium, supported by a fibro-vascular layer of variable tliickness below
it, and this merging into the submucous areolar tissue. It is only in some situa-
tions that the basement-membrane can be demonstrated.
The fibro-vascular layer of the coriiim contains, besides the white and yellow
fibrous tissue and the vessels, muscular fibre-cells, forming, in many situations,
a definite layer, called the muscularis mucosse^ nerves, and lymphatics in various
proportions. Embedded in it are found numerous glands, and projecting out of
it are processes (villi and papillas) analogous to the papillse of the skin. These
glands and processes, however, exist only at certain parts, and it will be more
convenient to refer for their description to the sequel, where the parts are
described in which they occur.- Thus the mucous glands are described in the
account of the mouth, the stomach, the intestines, &c., the papillae and villi with
that of the tongue.
The synovial membranes are analogous in structure to the serous, but differ
from them in the nature of their secretion, which rather resembles mucus. They
will be described hereafter.
SECRETING GLANDS.
The Secreting Glands are organs in which the blood circulating in capillary
vessels is brought into contact with the epithelial cells of a mucous membrane,
whereby certain elements are separated (" secreted") out of the blood, and are
poured into the mucous cavity. This cavity is arranged in the form of a ramify-
ing duct, the secreting cells lying in, or touching, the terminal ramifications (or
more correctly the commencing radicles) of the duct.
In size the glands vary extremely : thus the liver weighs nearly four pounds,
while many of the mucous glands' are only visible to the naked eye when dis-
tended with secretion : and they vary not less in structure. Thus the structure
of the liver is so complex that it can hardly yet be regarded as known with abso-
lute certainty ; while there are a great many glands which consist either of a
single tube lined with epithelium, on the outer side of which the blood circulates,
or even a simple closed sac which opens when it becomes charged with secretion.
The great majority of glands, however, can be reduced ideally to a very simple
form, viz., to an involution more or less complex of the basement-membrane,
carrying of course its epithelium with it, and having the capillary vessels distri-.
buted on its attached surface. If this involution be perfectly simple, an open
tube results, as in the stomach (see Fig. 436) or the common mucous crypts of
the urethra ; and should the mouth of such a tube become closed, a simple
follicle is formed, as in the intestine (Figs. 443, 447). Branches projecting out
from the bottom of this tube constitute the simplest form of racemose gland.
The most rudimentary condition of such a gland is shown in the branched tubes
of the gastric mucous membrane (see Fig. 436). If such a tube be conceived of
as divided into branches as well as branching out at its extremity, we have a
compound racemose gland consisting of a single lobule terminating in its duct
(such as Brunner's glands), and an aggregation of such lobules may all open
into a common duct, or may have a great number of separate ducts. Instances
of such glands will be found in the salivary glands, the pancreas, &c. Or the
necessary extent of epithelial surface may be obtained by the duct being coiled
on itself, as in the sweat-glands (Fig. 53), or the extremity of the duct only may
be thus arranged (see Fig. 499). In other glands, as in the kidney, the mucous
duct is undivided from the beginning, and the capillaries from which the secre-
tion is to be eliminated are distributed upon its walls or project into its ampul-
lated commencement (Fig. 483).
(For the description of the Ductless or Blood Glands, we must refer to the
sections in the text relating to the Anatomy of the Spleen, Suprarenal Capsules,
Thyroid, and Thymus.)
Growth and Development of the Body.
Fig. 61.
2^000, peUur
Cerinaud v
Ctrnand 'pot
-Jliscuzin
Ovum of the Sow.
The wliole body is developed out of tlie ovum (Fig. 61) wlicn fertilized by
the spermatozoa. Tlie ovum is merely a simple nucleated cell, or collection of
protoplasm, and tlie spermatozoa disappear wlien they have accomplished their
mysterious function. All the complicated changes by which the various intricate
organs of the whole body are formed from one simple cell may be reduced to
two general processes — viz., the segmentation or
cleavage of cells, and their differentiation. The for-
mer process consists in the splitting of the nucleus
and its investing cell-wall, whereby the original
cell is represented by two. The differentiation of
cells is a term used to describe that unknown power
or tendency impressed on cells which, to all methods
of examination now known, seem absolutely iden-
tical, whereby they grow into different forms; so
that (to take the first instance which occurs in the
growth of the embryo) the indifferent cells of the
vascular area are differentiated, some of them into blood-globules, others into
the solid tissue which forms the bloodvessels.
The extreme complexity of the process of development renders it at all times
difficult to describe it intelligibly, and still more so in a work like this, where
adequate space and illustration can hardly be afforded, having respect to the
main purpose of the book. I can only hope to render the leading features of
the process tolerably plain, and must refer the reader who wishes to follow the
various changes more minutely to the special works on the subject, and especially
the work of Foster and Balfour.
Many of the statements which are accepted in human embryology are made
only on the strength of experiments on lower animals, direct observation in the
human subject being impossible.
The ovum is a small spheroidal body situated in immature Graafian vesicles
near their centre, but in the mature ones in contact with the membrana granu-
losa^ at that part of the vesicle which projects
from the surface of the ovary. The cells of the
membrana granulosa are accumulated round the
ovum in greater number than at any other part
of the vesicle, forming a kind of granular zone,
the discus proligerus.
The human ovum (Fig. 62) is extremely minute,
measuring from slxj-th to jicyth of an inch in
diameter. It is a cell, consisting externally of a
transparent envelope, the zona pellucida or vitel-
line membrane. Within this, and in close con-
tact with it, is the yolk or vitelhis ; embedded
in the substance of the yolk is a small vesicular
body, the germinal vesicle (vesicle of Purkinjc) —
tlic ]iuclciis of tlie cell; and lliis contains as its nucleolus a small spot — the
macula germinativa., or the spot of Wagner.
The zona pellucida^ or vitelline memhrane^ is a thick, •colorless, transparent
membrane, which appears under the microscope as a bright ring, bounded ex-
Human ovum, from a middle- sized fol-
licle (magnified 350 times), a. Vitelline
membrane or zona pellucida. b. External
border of the yolk and internal border of
the vitelline membrane, c. Germinal
vesicle and germinal spot.
(94)
Sec tlic description of tlie Oviiry in tlic body of tlic work.
FECUNDATION OF OVUM.
95
ternallj and internallj by a dark outline. It corresponds to the cliorion of tlie
impregnated ovum.
The yolh consists of granular protoplasm — i.e. granules or globules of various
sizes, embedded in a more or less viscid fluid. The smaller granules resemble
pigment ; the larger granules, which are in greatest number at the periphery of
the yolk, resemble fat-globules. In the human ovum, the number of granules
is comparatively small.
The germinal vesicle consists of a fine, transparent, structureless membrane,
containing a watery fluid, in which are occasionally found a few granules. It
is about 7 2cth of an inch in diameter, and in immature ova lies nearly in the
centre of the yolk ; but, as the ovum becomes developed, it approaches the sur-
face, and enlarges much less rapidly than the yolk.
The germinal spot occupies that part of the periphery of the germinal vesicle
which is nearest to the periphery of the yolk. It is opaque, of a yellow color,
and finely granular in structure, measuring from ggVo to g^V^th of an inch.
The phenomena attending the discliarge of the ova from the Graafian vesicles,
since they belong as much or more to the ordinary function of the ovary than
to the general subject of the growth of the body, are described with the anatomy
of the ovaries in the body of the work.
It should be added that in the mature ovarian ovum the germinal vesicle has
disappeared. Some cells belonging to the membrana granulosa adhere for a
time to the surface of the ovum, but these also soon disappear.
The first changes in the ovam which take place upon conception, appear to
be as follows : — The spermatozoon penetrates the ovum,^ the effect of which is
to bring it into contact with the yolk, and with the germinal vesicle contained
in the yolk. It seems as if this normally occurs in the Fallopian tube,^ and ab-
normally it may even take place in the peritoneal cavity. The first effect is to
produce a cleavage and multiplication of the yolk, which becomes first cleft into
two masses, then into four, and so on, until at length a mulberry-like agglomera-
tion of nucleated cells results (Fig. 63). Ova in which this segmentation extends
Fig. 63.
Four diagrams to show the division of the yolk. The ovum is surrounded by spermatozoa,
puscles (polar globules of Kobin) are seen in the first two.
The clear cor-
over the whole yolk (which is the case with the mammalia) are called liohhlastic
ova ; those in which only a portion of the yolk is segmented are called mero-
hlastic.
There are also found within the vitelline membrane one or more clear glob-
ules, called " polar globules" by Eobin, because they lie near one of the poles of
segmentation. The nature, origin, and uses of these bodies are not known. They
seem to be usually regarded as produced by the liquefaction of the yolk, and
as not being essential to the process of fructification.
The globules of which the yolk is now composed soon arrange themselves
into the form of a membrane lined with pavement-epithelium. As the yolk-
mass softens, fluid accumulates in the interior of this membrane, spreading it
' See Newport, Phil. Trans. 1853, vol. ii. p. 233. This has been since confirmed by other ob-
servers on various lower animals, and may be assumed to be generally true.
^ Many physiologists, as Bischoff and Dr. M. Barry, taught that the ovum is fecundated in
the ovary, but the reasoning of Dr. Allen Thomson appears very cogent in proving that the usual
spot at which the spermatozoon meets with the ovum is in the tube.
96
GENERAL ANATOMY.
out on tlie internal surface of tlie vitelline membrane. Tlie latter (external)
membrane (Fig. QQ) soon becomes covered witli granulations or vegetations,
wbicli give it a shaggy ajDpearance, and it then
takes the name of the "primitive chorion;"
whilst the internal membrane, produced by the
cleavage of the yolk, is called the " blastodermic
membrane or vesicle."
Tlie ovum increases in size during the whole
of this time, by the absorption of albuminous
fluid which coats it during its descent along the
Fallopian tube, and which is secreted by the
mucous membrane lining that tube.
The first stage towards the formation of the
embryo is the cleavage or splitting of the blasto-
derm. This process has been accurately fol-
lowed out in birds, in whose ova (meroblastic)
the blastoderm only covers a portion of the
yolk, and is divided originally into two layers,
the lower of which soon splits again into two,
so that three separate layers of cells result. In
the human embryo also the three layers of
which the blastoderm is ultimately composed are believed to originate in a simi-
lar manner, though no direct observations have hitherto been made in mamma-
lia which cover the whole period of the formation of the blastodermic membranes.
But in both classes of ova they consist ultimately of three — the external, which
iised to be called the serous layer, but to which the term ejnhlast is now more
commonly applied ; the internal, the mucous layer, or hyjoohlast ; and the middle,
which is believed by most writers to be originally developed by cleavage from
the hypoblast, and which is now usually called the mesohlast, formerly the vas-
cular layer. The precise mode of formation of this middle layer is, however, by
no means exactly made out. All the layers consist hitherto of nucleated cells,
in which up to this time no special arrangement or differentiation is perceptible.
Observations on the fowl's egg, however, have led Foster and Balfour to the
conclusion that the cells of the epiblast are the direct results of segmentation
from the original germ-cell, while those of the hypoblast and mesoblast are de-
rived from certain "formative cells" which make their appearance in the yolk
cavity, migrating into it by the help of amoeboid movements after the fashion
of white blood-corpuscles.
Ovum with the germinal area, seen in
profile to show the division of the blasto-
dermic membrane. 1, vitelline membrane.
2, blastoderm. 3, srerminal area. 4, place
■where the blastoderm is just divided into
its two layers.
Sention of a blastoderm at right angles to the long axis of the embryo, near its middle, after eight hours'
incubation (from Foster and Balfour). A, epiblast formed of two layers of cells; B, mesoblast thickened
below the primitive groove; O, hypoblast formed of one layer of Hattencd cells ; pr, primitive groove ; mc,
mesoblast cell ; bd, formative cells in the so-called segmentation or snbgerminal cavity. (The line of sei)arn-
tion between the cijitilaHt and mesoblast below the primitive groove is too strongly marked in the figure.)
TIk; epiblast is mainly concerned in the formation of the external cuticle and
of ihe nervous centres. From it proceed all the epidermis of the body and all
BLASTODERM.
97
Fig. 66.'
Diagrams to show the development of the three layers of the blastodermic membrane on transverse sections.
A, portion of the ovum with the zona pellucida and the germinal area. B O D E F G, different stages of
development, o, umbilical vesicle, a, amnion, i, intestine. ^, peritoneal cavity, bounded by the splanchno-
pleural and somato-pleural layers of mesoblast. 1, vitelline membrane. 2, external blastodermic layer. 3,
middle layer. 4, internal layer. 5, medullary laminee and groove. 5', medullary canal. 6, epidermic laminae.
V, lateral flexures of the amnion. 7', the same almost in contact. 8, internal epithelial layer of the amnion.
9, epidermis of the embryo. 10, chorda dorsalis. 11, vertebral lamina. 12, protovertebree jjroper. 13, mus-
cular laminae. 14. lateral laminte. 15, fibro-intestinal laminae. 16, cutaneous laminae. 17, internal fibrous
layer of the umbilical vesicle. 18, muscular laminae extending to meet the cutaneous. 19, external layer of
the cutaneous laminae. 20, internal layer of the same. 21, mesentery. 22, fibrous layer of the intestine.
' The dotted lines indicate the parts belonging to the internal blastodermic layer ; the plain
lines those belonging to the middle ; the interrupted lines those belonging to the external. The
embryo has been represented, in this and the following diagram, lying on its back. The natural
position is generally assumed to be the reverse.
7
98 GENERAL ANATOMY.
the involutions of the epidermis in tlie ducts of the glands and of the mammse,
the brain, the spinal cord, and the portions of the nose, eye, and ear which are
directly formed from the brain. The external layer of the amnion is also formed
from the epiblast, and probably a portion of the chorion.
The hypoblast is mainly concerned in forming the internal epithelium, viz.,
that of the whole alimentary passages, except the mouth and a small portion of
the rectum near the anus (which are formed by an involution of the integu-
ment) ; that of the respiratory tract, which is originally an offset from the ali-
mentary canal ; and the epithelium of all the glandular organs which open into
the internal tract. The hypoblast forms also the deeper layer of the umbilical
vesicle and allantois.
All the rest of the embryo is formed from the mesoblast, viz., all the vascular
and locomotive system, the cutis, all the connective tissues, the nerves,^ and the
genito-urinary organs, through the Wolffian bodies and other temporary foetal
structures. The vascular system of the foetus extends to the yolk and the
maternal parts along the umbilical vesicle and allantois, so that the greater part
of these bodies and the outer layer of the amnion are also formed out of the
mesoblast. The foetal portion of the placenta, being essentially a vascular
strncture, is also developed from the mesoblast.
The method of formation of these various parts, and especially the mode of
conversion of the mesoblast, is, however, very complicated.
Germinal area. — -In the mass of nucleated cells into which the yolk becomes
converted during the formation of the blastodermic vesicle, a small agglome-
ration is formed, which then spreads out into an area of nucleated cells, from
which the embryo is to be formed, and which has accordingly received the name
of germinal disk or area germinativa. In this portion of the ovum the first trace
of the embryo appears as a faint streak, which is called the primitive trace or
primitive groove (Fig. 65). This groove first deepens into a furrow, bounded by two
plates — the laminse dor sales ^ beneath which a delicate fibril appears — the chorda
dorsalis or notochord — in which cartilage can very early be recognized.
The chorda dorsalis and the laminae dorsales are the rudiments of the vertebral
column and canal.
The first approaches towards a definite form in the embrj'o are made (1) by
the development of the rudimentary spinal column, (2) by the cleavage of the
middle layer of the blastodermic membrane, from which a part of that column
is derived, and (3) by the incurvation of the column at its cephalic end to form
the brain and brain-case.
The heaping up of the epiblast in the germinal area gives rise to a distinct
longitudinal streak, which, when looked at from above, is seen to be constricted
in the middle. Soon this heaped-up epiblast constitutes a distinct groove, the
sides and base of which are formed of epiblastic cells (Fig. 68 a). The margins
of the groove then coalesce, first in the middle of the embryo, then towards the
cephalic end, which is soon seen to be more dilated than the rest and to pre
sent constrictions dividing it imperfectly into three chambers, and lastly at the
caudal extremity. Thus a closed tube is formed lined with epiblast and having
a covering of the same membrane (Fig. 68 b). The lining of the tube is developed
into the nervous centres, the covering into the epidermis of the back and head.
Below this primitive cerebro-spinal canal lies the mesoblast, and from this are
developed (1) a continuous rod-shaped body lying beloAV the jirimilive groove,
and called the notochord; (2) on either side a substance divided into a number of
square segments (the protovertehrse), which first make their appearance in the
region which afterwards becomes the neck, then further forwards towards the
head, and afterwards extend along the body. These protovcrtcbras, as will be
explained hereafter, are not the same as the permanent vertebrae ; but they are
' Tn tlio spinal norvos tho part which is in cnnnoction ■vvilh 1ho cord, including- the ganglia, is
furnicd from tho inesublabt, accordiii'^ to the most recent observations.
BLASTODERM.
Fig. 67.'
99
Diagrams to show the development of the three blastodermic layers on antero-postpTior sections. A, por-
tion of ovum with the vitelliue membrane and germinal area. B O D E K, various stages of development.
G, ovum in the uterus and formation of decidua. 1, vitelline membrane. 2, external blastodermic layer. 2',
vesicula serosa. S, middle blastodermic layer. 4, internal layer. 5, vestige of the future embryo. 6, cephalic
flexure of the amnion. 7, caudal flexure. S, spot where the amnion and vesicula serosa are continuous. 8',
posterior umbilicus. 9, cardiac cavity. 10, external fibrous layer of the umbilical vesicle. 11, external fibrous
layer of the amnion. 12, internal layer of the blastoderm forming the intestine. 13,14 externallayer of the
allantois extending to the inner surface of the vesicula serosa, 15, the same now completely applied to the
inner surface of the vesicula serosa. 16, umbilical cord. 17, umbilical vessels. 18, amnion. 19, chorion. 20,
fcetal placenta. 21, mucous membrane of uterus. 22, maternal placenta, 23, decidua reflexa, 4, muscular wall
of uterus.
• The same note applies to this as to the preceding 3iagrara.
100 GENERAL ANATOMY.
differentiated partly into the vertebrae, partly into the nmscles and true skin,
and partl}^ into the roots and ganglia of the nerves.
Fig. 68.
i_5
Transverse section through the embryo-chick before and some time after the closure of the medullary canal,
to show the upward and downward inflections of the blastoderm (after Eemak). A, at the end of the first day-
], notochord ; 2, primitive groove in the medullary canal ; 3, edge of the dorsal lamina ; 4 corneous layer or
epiblast ; 5, mesoblast divided in its inner part ; 6, hypoblast or epithelial layer ; 7, section of protovertebral
plate. B, on thethird day in the lumbar region. 1, notochord in its sheath ; 2, medullary canal now closed
in ; 3, section of the medullary substance of the spinal cord ; 4, corneous layer; 5, somatopleure of the meso-
blast; 5', splanchno])leare (one figure is ])laced in the pleuro-peritoneal cavity); 6, hypoblast layer in the
intestine and spreading over the yolk ; iX^i Part of the fold of the amnion formed by epiblast and somatopleure.
On either side of the protovertebrse, the mesoblast splits into two layers, the
npper of which, or that lined by epiblast, is called somatoplenre, and the lower
(lined by hypoblast) splanchnopleure (Fig. 68, B, 5, 5'). From the former the
skeleton, muscles, and true skin of the external parts of the body are derived ;
from the latter, the muscular and other mesoblastic portions of the viscera.
The space between them is the common pleuro-peritoneal cavity. Whilst the
parietes of the body are still unclosed, this common peritoneal cavity is con-
tinuous with the space between the amnion and chorion as seen in Fig. QQ, F.
The embryo, which at first seems to be a mere streak, extends longitudinally
and laterally. As it grows forwards it becomes remarkably curved on itself
(cephalic flexure), and a smaller but distinct flexure takes place at the hinder
end (caudal flexure). At the same time the ' sides of the embryo grow and
curve towards each other, so that the embryo is aptly compared to a canoe
turned over (see Fig. 69). The well of the canoe opens freely into the cavity
of the yolk-sac. Its walls are of course formed by the three blastodermic
membranes, and at the point where the well commences (the future umbilicus)
the outer (epiblast), lined by the somatopleural layer of mesoblast, turns back
over the canoe on all sides till the folds meet at the point opposite the umbilicus :
then the two sides communicate with each other, and thus a closed serous sac,
the amnion, is formed (Fig. 69), Meanwhile the yolk-sac communicates freely
with the interior of the embryo, through the large opening which afterwards
becomes the umbilicus, and which we have likened to the well of the canoe
(Pig. (^(y, B, c);^ and through this opening the internal blastodermic membrane
and the internal or splanchnopleural division of the mesoblast pass out. In
those animals which have no amnion, all three layers pass over the yolk-sac;
but where the amnion exists it separates the external blastodermic layer from
the yolk-sac or umbilical vesicle, as shown in the figures. This umbilical vesicle
is therefore at first a mere part of the general cavity of the yolk, partly enclosed
by the embryo; but as the latter grows round on all sides towards the umbilical
aperture, the yolk-sac becomes distinguished into two portions, one lying inside
the embryo and forming a portion of the intestinal cavity (out of which the
student must remember the bladder is also formed), and therefore forming a
part of tlie body of the fcx3tus, and the other lying external to the body, and
' 'I'he Rtiulent, will rpmombor tliat in Fips. fifi, fi7. Ilio embryo is roprpsontcrl as lyincf on its
back : but the position in which the spinal column is highest is usually dcsciibod as the natural
one, as in Fig. 69.
THE AMNION
101
remaining therefore as a part of wliat is, in a more restricted sense, tlie ovum.
The two parts communicate by a passage — the omphalomesenteric duct — the
destination of which will be pointed out presently. The extra-embryonic portion
of the umbilical vesicle is of small importance and very temporary duration in
the human subject. It is the seat of the earliest circulation, but is early replaced
in that capacity by the allantois, which becomes the great bond of vascular
connection between the embryo and the uterine tissues, as will be explained
presently. As the arteries developed in the middle blastodermic layer grow,
"they cover the umbilical vesicle, forming the vascular area^ the chief vessels of
which are the omphalomesenteric^ two in number. The vessels of this area
appear to absorb the fluid of the umbilical vesicle, which dries up into a disk-
like body attached to the amnion, and having no further function. The activity
of the umbilical vesicle ceases about the same time (fifth or sixth week) as the
allantois is formed. In fact, the umbilical vesicle provides nutrition to the
fcetus from the ovum itself, while the allantois is the channel whereby nutrition
is conveyed to it from the uterine tissues. The umbilical vesicle, however, is
visible, containing fluid, up to the fourth or fifth month, between the amnion
and the chorion, with its pedicle and the omphalomesenteric vessels. The latter
vessels then become atrophied, as the functional activity of the body with which
they are connected ceases.
The Amnio7i. The first step towards a clear understanding of the development
of the embryo is to have a proper conception of the method and the object of
the formation of the amnion and of the cleavage of the blastoderm (its middle
layer) into two portions at the unclosed portion of the embryo. The object of
this cleavage is to form the common pleuro-peritoneal cavity, and to conduct
out, along the umbilical vesicle and the allantois, the vessels by which the vital
vascular connection between the foetus and the ovum or the mother is to be
established.
Fjo-. 69.
'\sjJkJi
""^ITWS^
niigrammat-ic section through the ovum of a mammal in the lonsr axis of the embryo, e, the eranio-verte-
bral axis; i, i, the cephalic and caudal portions of the primitive alimentary canal ; a, the amnion; a', the
point of reflection into the false amnion; v, yolk-sac, communicating with the middle part of the intestine
by V i, the vitello-intestinal duct ; ii, the allantois. The ovum is surrounded externally by the villous chorion.
The amnion is the membrane which immediately surrounds the embryo. It
is of small size at first, but increases considerably towards the middle of preg-
nancy, as the foetus acquires the power of independent movement. Its cavity
is occupied by a clear serous fluid, the liquor amnii, which contains about 1 per
102 GENERAL ANATOMY.
cent, of solid matter, albumen witli traces of urea. The quantity of this fluid
increases up to about tlie sixtli montli of pregnancy,, after which, it diminishes
somewhat. The use of the amnion is believed to be chiefly to allow of the
movements of the foetus in the later stages of pregnancy, though it serves no
doubt other purposes also. Its external layer, derived from the mesoblast, is
now described as being muscular, at least as displaying rhythmic contractions
during life. The internal layer is derived from the epiblast.
The amnion is thus formed. As the embryo grows it becomes curved in front
and behind — the cephalic and caudal flexures; and as these flexures increase
they pucker up the embryo towards a wide opening or dehiscence below, the
situation of the future umbilicus. The embryo also curves over laterally towards
the same point. The external blastodermic layer (epiblast) is reflected at the
flexures of the embryo, in the manner shown in Fig. 67, from the body of the
embryo on to the umbilical vesicle and allantois. As the allantois, at least its
vascular portion, extends over the whole yolk-sac, to line the chorion internally,
it carries the amnion with it until its caudal and cephalic portions come into
contact (at a'. Fig. 69), meet, and coalesce, forming a simple closed cavity. This
internal or epithelial lining of the amnion derived from the epiblast is coated
over by a fibrous (or muscular?) layer, which is furnished by the somatopleural
part of the mesoblast, as above explained and figured.
The amnion is destitute of vessels. It is exclusively a foetal structure, and
in no obvious connection with the parts which are truly uterine.
The part of the amnion which was at first in contact with the chorion (and
which is shown in Fig. 69 by the dotted line on either side of a') is called the
" false amnion," or vesicula serosa. When the amniotic folds come together and
communicate, this is entirely separated from the amnion proper, and is either
obliterated or takes a share in the development of the chorion. In mammals the
epiblast only is believed to be concerned in the formation of the false amnion.
The Allantois is the chief agent of the early circulation, i. e., the duct or tract
along which the vessels extend which convey the blood of the embryo to the
foetal chorion, where it is exposed to the influence of the maternal blood circu-
lating in the decidua or uterine portion of the chorion, from which it imbibes
the materials of nutrition, and to which it gives up those matters which are
necessary for its purification. The alantois is formed hy a projection of the
internal germinal layer (hypoblast), taking with it the splanchnopleural layer
of the mesoblast, in which latter the vessels are formed which constitute its
most important part. It is at first a mere hollow projection out of the common
intestinal cavity (Fig. 67 c), but it soon extends into and through the pleuro-
peritoneal space till it meets with the primitive chorion, and to this it contributes
its essential foetal portion, the fibrous or vascular layer of the allantois. The
epithelial or internal portion of the allantois, formed by the hypoblast, is hollow,
and is usually styled the allantoic vesicle. The part of the allantoic vesicle
outside the embryo soon withers and disappears in the human foetus, while the
vascular part grows and develops into the umbilical cord. The part of the
allantois internal to the embryo forms, or contributes to form, the bladder below,
while its upper portion becomes impervious, and is called the urachus.
In the embryos of those animals in which the whole yolk-sac is taken up into
the body of the embryo, there is no amnion and no allantois ; but whenever
the amnion is formed an allantois is also formed. In the former case the embryo
is nourished directly by transudation into the yolk. In the latter the yolk is
of subordinate imy)ortance ; the foetus deriving its nourishnicnt from the uterus
through the vascular connection established between the allantois and decidua,
or later between the foetal elements of the placenta, derived from the allantois,
and the maternal, derived from the decidua.
Hie Chorion. At the time wc have just been speaking of, the envelope of
the ovum consists cxternany of the vitelline membrane, I'mod internally by the
amnion. Tlie allantois, or rather the fibro-vascular ])orti(>n of the allantois,
grows ill between these two membranes, applies itself to the vitelline membrane,
THE CHORION.
103
and forms witli it the foetal portion of the chorion.^ Between this membrane
and tlie amnion there is a space (Fig. 67) wliicli is described by Dalton as occu-
pied by a semi-fluid gelatinous mateiial, somewhat similar to that of the vitreous
body of the eye, and a similar material forms the bulk of the umbilical cord. The
umbilical vesicle, as is seen in the figures, lies in this space, which is the primitive
pleuro-peritoneal cavity, or interval between the somato-pleural, and splanchno-
pleural layers of the mesoblast. Soon the surface of the foetal chorion shows
villous processes, from which circumstance it is known as the " shaggy chorion."
Fig. 70.
Magnified view of the human embryo of four weeks with the memhranes opened (from Ijeishman after
Coste). y, the umbilical vesicle with the omphalomesenteric vessels, v, and its long tubular attachment to
the intestine ; c, the villi of the chorion ; m, the amnion opened ; u, cul-de-sao of the allantois, and on each
side of this the umbilical vessels passing out to the chorion ; a, in the embryo, the eye ; e, the ear vesicle ; h,
the heart ; I, the liver ; o, the upper, p, the lower limb ; w, WolfSan body, in front of which the mesentery and
fold of intestine. The Wolffian duct and tubes are not represented.
These villi are projections formed to receive the outgrowths of the foetal
vessels ; but the villi are formed before they receive any vessels, and are at first,
as figured by Dalton,^ mere cellular fingers or processes, likened by him to the
' The precise part of the ovum from which the chorion is originally developed is not certainly
determined. I have here followed the authorities who derive it from the vitelline membrane, but
it is believed by others to be developed from the epiblast reflected over that membrane. A
reference to fig's. 66, 69, will show the student how easily the vitelline membrane may receive a
covering of epiblast in an early period ; and the point can hardly be settled for the human ovum,
except by inference from observations on lower animals, and such observations are rendered
uncertain in consequence of the immature condition of the ovum at this period. Foster and
Balfour say on this point, " 'I'he false amnion either coalesces with the vitelline membrane, in
contact with which it lies, or else replaces it. and in the later days of incubation is known as the
chorion." These authors therefore trace epiblastic elements into the chorion, and possibly meso-
blastic also, in the chick.
2 Dalton's " Physiology," 5th ed p. 630.
104 GENERAL ANATOMY.
tufts of seaweed. Into these tufts tlie growing vessels of the allantois with their
connective-tissue envelope project. These villi cover at first the whole surface
of the chorion ; but as development progresses and the placenta is about to be
formed, by which the extent of the attachment of the ovum to the uterine walls
is to be limited (whilst the energy of its nutrition is no doubt to be indefinitely
increased), the villi disappear over the rest of the chorion, and are confined to
that part only which is to form the foetal portion of the placenta.
The Decidua. The growth of the chorion and placenta can only be under-
stood by tracing the formation of the decidua.
The decidua (Figs. 67, 71) is formed from the mucous membrane of the uterus.
Even before the arrival of the fecundated ovum in the uterus, the mucous mem-
brane of the latter becomes vascular and tumid, and when the ovum has reached
the uterus, it is embedded in the folds of the mucous membrane, which overlap,
and finally completely encircle the ovum. Thus two portions of the uterine
mucous membrane (decidua) are formed — viz. that which coats the muscular
wall of the uterus, decidua vera^ and that which is in contact with the ovum,
decidua reflexa. The decidua does not extend into the neck of the uterus, which
after conception is closed by a plug of mucus. The decidua vera is perforated
by the openings formed by the enlarged uterine glands, which become much
hypertrophied and developed into tortuous tubes. It contains at a later period
numerous arteries and venous channels, continuous with the uterine sinuses, and
it is from it that the uterine part of the placenta is developed. The portion of
the decidua vera which takes part in the formation of the placenta is called
" decidua serotina."
The decidua reflexa is shaggy on its outer aspect, but smooth within. Tlie
vessels which it contains at first disappear after about the third month : about
the fifth or sixth month the space between the two layers of the decidua dis-
appears, and towards the end of pregnancy the decidua is transformed into a
thin yellowish membrane, which constitutes the external envelope of the ovum.
Much additional interest has been given to the physiology of the decidua by
the fact, which seems to be now established by the researches of Dr. John Williams,
that every discharge of ova is, as a rule, accompanied by the formation of a
decidua, and that the essence of menstruation consists in the separation of a
decidual layer of mucous membrane from the uterus.
The Placenta is the organ by which the connection between the foetus and
mother is maintained, and through which blood reaches the foetus and is returned
to the uterus. It therefore subserves the purposes both of circulation and respi-
ration. It is formed of two parts, as already shown — viz., the maternal portion
which is developed out of the decidua vera (serotina), and the foetal placenta
formed by the villous chorion. Its shape in the human subject is that of a disk,
one side of which adheres to the uterine walls, while the other is covered by
the amnion. The villi of the chorion (or foetal placenta) gradually enlarge,
forming large projections — ^'■cotyledons''' — which each contain the ramifications
of vessels communicating with the umbilical arteries and veins of the foetus.
These vascular tufts are covered with epithelium, and project into corresponding-
depressions in the mucous membrane of the uterine walls. The maternal portion
of tlie placenta consists of a large number of cells formed by an enlargement
of the vessels of the uterine wall, and conveying the uterine blood into close
proximity to the villi of the fcetal placenta, wliicli dip into these cells. The
interchange of fluids, necessary for the growth of the foetus, find for the depura-
tion of the blood, takes place through the walls of these villi, but there is no
direct continuity between the maternal and foetal vessels. The arteries open
into the placental cells somewhat after the manner of the erectile tissue. Tlie
veins anastomose fre(;]y Avitli one another, and give rise at the edge of the
placenta, to a venous channel which runs around its whole circumference — the
'placental sinus.
The Umhilical Cord ai)pcars about the end of the fifth month after pregnancy.
GROWTH OF THE EMBRYO,
105
It consists of tlie coils of two arteries
(umbilical) and a single vein, united
together by a gelatinous mass (gelatin
of Wharton) contained in the cells of
an areolar structure. There are origi-
nally two umbilical veins, but one of
these vessels becomes obliterated, as
do also the two omphalomesenteric
arteries and veins, and the duct of the
umbilical vesicle, all of which are
originally contained in the rudimentary
cord. The permanent structures of the
cord are therefore those furnished by
the allantois.
Growth of the Emhryo. The youngest
human embryos which have been met
with are two described by Dr. A. Thom-
son in the " Edin. Med. and Surg,
Journal," 1839, and in his paper refer-
ences to the other extant descriptions
of early ova will be found. The ova in
question were believed to be of the ages
respectively of twelve to fourteen days,
and about fifteen days.^ The figures
are here reproduced. The earliest
ovum (Fig. 72) was /„ of an inch in
diameter, when freed from some adhe-
rent decidua. The chorion presented
a slightly villous appearance, and con-
sisted only of one layer of membrane.
On opening it the umbilical vesicle and
embryo were found not to fill its cavity
completely. The embryo was a line in
length, and nearly jj^ of an inch in
thickness. The chorion was united to
the embryo and umbilical vesicle by
a thin tenacious web of albuminous
filaments, formed probably by coagu-
lation in the spirit in which it had been kept. There were no vessels on the
umbilical vesicle. The abdomen of the embryo presented no appearance of
intestine, but merely a long shallow groove, forming a common cavity with the
yolk-sac. Around this intestinal groove the germinal membrane was continuous
with that on the surface of the yolk-sac. One extremity of the embryo,
probably the cephalic, was enlarged, but this the author believed to be acci-
dental. A more opaque and expanded portion between the cephalic extremity
and the surface of the yolk-sac appeared to him to indicate the rudimentary heart.
The second embryo (Figs. 73, 74) was in a slightly more advanced condition.
In it, as in the former, the amnion and allantois were not found, though the
adhesion of the embryo by its dorsal aspect to the inner side of the chorion
renders it probable that the amnion was formed. The cephalic and caudal ex-
tremities could be easily distinguished; the vertebral groove appeared to be
open in its whole extent ; there was a more perfect intestinal groove than in the
former case, and there was an irregular-shaped mass between the yolk and the
. ^ For the data on whicli these calculations are founded, the reader is referred to the original
paper.
Sectional plan of the gravid uterus, from Wagner,
in the third and fourth month, a, jjlug of mucus in
neck of uterus, b, Fallopian tube, c, the decidua
vera; c', the decidua vera passing into the right
Fallopian tube: the cavity of the uterus is almost
completely occupied by the ovum ; e e, points of the
reflection of the decidua refiexa (in nature the united
deciduse do not stop here, but pass over the whole
uterine surface of the placenta) ; g, supposed allantois ,
h, umbilical vesicle ; i, amnion ; k, chorion, covered
with the decidua reflexa ; d, cavity of the decidua ; /,
decidua serotina, or placental decidua.
106
GENEEAL ANATOMY.
ceplialic extremity of tlie embryo, wliich Professor Thomson believed to be tlie
rudiment of tlie lieart. No distinct trace of the omphalomesenteric vessels could
be observed.^
Fig. 72.
Fiff. 73.
Fie-. 74.
Human ovum, 12 to 14 days.
1, natural size. 2, enlarged.
Human ovum,
15 days.
Embryo from the preceding ovum. 1, umbilical
vesicle. 2, medullary groove. 3, cephalic por-
tion of the embryo. 4, caudal portion. 5, frag-
ment of membrane (amnion t).
Fiff.
In an embryo of fifteen to eighteen days, described by Coste, the villi of the
chorion were well formed, the umbilical vesicle communicated largely with the
intestine, and the allantois was present, united to
the inner surface of the chorion, and communicating
by a large pedicle with the intestine. Both the
allantois and umbilical vesicle were vascular. The
amnion was not yet closed.
In ova of the third and fourth week the amnion
has been found closed, the rudiments of the eye, ear,
maxillary projections, pharyngeal arches, cerebral
vesicles, anterior and posterior extremities, liver and
umbilical cord are observed (figs. 70, 75).
The further development of the embryo will per-
haps be better understood if we follow as briefly as
possible the principal facts relating to the chief
parts of which the body consists — viz., the spine,
the cranium, the pharyngeal cavity, mouth, &c., the
nervous centres, the organs of the senses, the circu-
latory system, the alimentary canal and its appen-
dages, the organs of respiration, and the genito-
urinary organs.^ The reader is also referred to
the chronological table of the development of the
foetus at the end of the Introduction.
Human embryo in the fourth week.
1, amnion removed in part of the dor-
sal region. 2, umbilical vesicle. 3,
omphalomesenteric duct. 4, inferior
maxillary tubercle of first i)haryngeal
arch. 5, superior maxillary tubercle
from the same arch. G, second pharyn-
geal arch. 7, third. 8, fourth. 9, eye.
10. primitive auditory vesicle. 11.
anterior extremity. 12, posterior ex-
tremity. 13, umbilical cord. 14, hea,rt.
1.5, liver.
Development of the Spine. The external layer of
the blastoderm (epiblast), as shown in Fig. 68, dips
down to form tlie medullary groove, which is after-""
wards converted into the medullary canal, and in
this canal the nervous centres are formed out of epiblastic elements. At the
same time the cliorda dorsalis, or notochord, is formed out of the mesoblast.
This is a rod or cylinder composed of a transparent tube containing cinbryo-
' A tliinl ofirly embryo is fifjiircd uiid clcscrilnMl in tliis paper, but tlie author is more uncertain
as to its age.
" The scope of this work only permits the briefest possible reference to these subjects. Those
who wish to study the subject of embryology in more detail are ref(M-red to Kiilliker's Enfvn'ckel-
inniNfjcKrJn'rh/e, to the chapters on the develoi)ment of the various organs in the Hth edition of
Quuin's Anat.onn/, or to the works o*" I*rof Dallon and of Foster and Balfour.
DEVELOPMENT OF SPINE
107
nic cells (Fig. 76) and extending from the cephalic to the caudal extremity of
the foetus below the spinal canal. On either side of this are laid down also
from the mesoblast a series of square-shaped bodies called the protovertebrse.
The protovertehrse or prwiitive vertehrse appear early, as dark spots, which soon
enlarge and form quadrangular laminae, one on either side of the chorda dor-
salis, commencing in the cervical region. These spread out and bend towards
each other, so as to come into contact around the spinal canal and inclose it,
forming the rudiment of the future bodies and arches of the vertebrte, as well as
of the vertebral and other muscles. This primitive vertebral column is, how-
Transverse section through the dorsal region of an embryo-chick, end of third day (from Foster and Balfour).
Am, amnion; m p, muscle plate ; cv, cardinal vein ; ^o, dorsal aorta at the point where its two roots begin
to join ; Ch, notchord ; Wd, Wolffian duct; Wb, commencement of formation of Wolffian body; ep, ejiiblast ;
so, somatopleure ; hy, hypoblast. The section passes through the place where the alimentary canal {hy) com-
municates with the yolk-sac.
ever, entirely membranous until about the sixth or seventh week, when carti-
lage begins to be deposited in it. The protovertebrse do not coincide with the
permanent vertebras. On the contrary, each primitive vertebra separates into
two parts, the upper part belonging to the permanent vertebra, which lies
above the point of separation, and the lower one to that below (Fig. 77). The
chorda dorsalis becomes gradually atrophied, except at the part corresponding
to the intervals between the permanent vertebree, where it forms the inter- ver-
tebral disks.
The steps by which the various parts of the spinal column are composed are
complicated, and in several points they are not at present clearly made out.
Thus the notochord is usually regarded, and is described above, as being formed
out of the mesoblast ; but this is denied by several authors, who refer its origin
to the epiblast, and who deny that any cartilaginous change takes place in it.
These authors would thus refer the intervertebral disks exclusively to the pro-
tovertebrjB, while the notochord would, according to them, disappear entirely in
after life.
What is usually admitted is shortly as follows : The protovertebrse, derived
from the mesoblast, increase in size and grow up around the notochord, so as to
108
GENERAL ANATOMY.
Fis-.
inclose it completely. Thej then become divided or segmented each into two
portions, tlie upper segment of tlie lower protovertebra coalescing with the lower
segment of the npper to form the corresponding segment of the whole trunk or
somatome. From each of these somatomes are to
be derived (1) the basis of the vertebra and, as
proceeding from this, the bony framework of the
portion of the skeleton to which the vertebra
serves as a centre ; (2) the muscular plates which
surround the vertebrse, and from which the mus-
cular elements extend into the limbs ; (3) the vas-
cular system ; (4) the ganglia which lie in the
intervertebral foramina, and the nerves which
proceed from these ganglia, and finally the true
skin below the epiblast and the corium of the
mucous membrane below the hj^poblast.
The mesoblastic elements (protovertebras) on
either side grow towards each other and coalesce,
surrounding the notochord and the epiblastic ele-
ments out of which the medullary canal has been
developed (Fig. 76 m c). From this portion of the
somatomes the laminas of the vertebrae, the mus-
cles and other parts in the vertebral grooves, and
the skin of the back are formed.
Cervical part of the primitive verte-
bral column and adjacent parts of an
embryo of the sixth day, showing the
division of the primitive vertebral seg-
ments (from Kolliker, after Remak).
1, 1, chorda dorsalis in its sheath,
])ointed at its upper end ; 2 points by
three lines to the original intervals of
the primitive vertebree ; 3 in a similar
manner indicates the places of new di-
vision into permanent bodies of verte-
brae ; c indicates the body of the first
cervical vertebra ; iu this and the next
the primitive division has disappeared,
as also in the two lowest represented,
viz., d and the one above; in those
intermediate the line of division is
shown; 4 points in three places to the
vertebral arches; and 5, similarly to
three commencing ganglia of the spinal
nerves; the dotted segments outside
these parts are the muscular plates.
Develop'ment of the Cranium in general, and of the
Face. The foetal cranium is developed from the
primitive vertebral disks surrounding the upper
extremity of the chorda dorsalis. These advance
in the form of a membranous capsule ("investing
mass" of Eathke) which covers the end of the
chorda dorsalis, form.ing the rudiment of the base
of the skull, and moulds itself on the cerebral vesi-
cles, so as to constitute the membrane in which the
vault of the skull is developed. The membranous
capsule presents at the base of the skull two
thickenings ("lateral trabeculje" of Rathke) di-
rected forwards, and inclosing an opening (pitui-
tary opening) which is partly closed by a thinner
membrane — the middle trabecula. The upper end
of the chorda dorsalis terminates in a pointed
extremity (Fig. 77), which extends about as far forwards as the body of the
sphenoid bone, where it becomes lost near the situation of the pituitary body.
The membrane becomes replaced by cartilage in the part corresponding to the
base of the skull and the trabecula3, A portion of this primitive cartilaginous
cranium becomes atrophied and disappears, a portion persists — forming the
cartilages of the nose and those of the articulations; the rest forms the carti-
laginous nidus of the basilar part of the occipital, the greater part of the
sphenoid, the petrous and mastoid portions of the temporal, the ethmoid bone,
and the septum nasi.
As the cerebral extremity of the foetus grows it becomes twice bent forwards
on its own axis (Fig. 79). The upper or posterior curvature is called the cerebral ;
the lower or anterior, the frontal protuberance. From the anterior end pf the
chorda dorsalis four prolongations proceed on either side, and meet in the
middle line (Figs. 70, 78, 4, 7, 8, 0). These arc the pharyngeal arches, and in
thf.m, and in the frontal protuberance, certain bones are developed, which are
called secondary bones, to distinguish tliem from those above enumerated, which
arc formed from the primitive cranium itself. Between the first pharyngeal
DEVELOPMENT OF THE SKULL,
109
Fiff,
arch and the frontal protuberance is situated the buccal depression, which after-
wards becomes the cavity of the mouth, or more properly of the fauces, for the
mouth itself is developed from the epiblast growing inwards, whilst these pharyn-
geal arches are formed from the mesoblast, lined internally by the hypoblast,
the reflection of which membrane closes the cavity above in the early state.
The frontal protuberance next gives off two lateral parts (lateral frontal protu-
berances), on each of which a depression is
formed, the olfactory fossa, bounded on either
side by the internal and external nasal pro-
cesses. There is a groove external to the
external nasal process, which afterwards is
transformed into the lachrymal canal, and
another groove leading from the olfactory
fossa to the buccal cavity — the nasal groove.
The first pharyngeal arch divides at its
anterior extremity into two parts — a superior
and inferior maxillary protuberance. The
latter unites very early to its fellow of the
opposite side to form the lower jaw. The
superior maxillary protuberances are dis-
placed outwards and unite to the external
nasal process; from this part are developed
the internal plate of the pterygoid process,
the palate bone, the superior maxillary and
the malar. The lateral masses of the eth-
moid, the OS unguis and nasal bones are fur-
nished by the internal nasal process. The
rest of these processes on either side is united
by a single protuberance, the incisive tubercle ;
from which the intermaxillary bone and the
middle of the upper lip are formed, and, ac-
cording to some, the vomer.
Besides the lower jaw, the inferior maxil-
lary protuberance furnishes a transitory car-
tilaginous mass — the cartilage of Meckel — from which the malleus and incus are
formed. The remains of Meckel's cartilage persist as long as till the end of the
seventh or the eighth month of foetal life, in the form of a rod of cartilage lying-
inside the lower jaw. From the second pharyngeal arch are formed the stapes
and stapedius muscle, the pyramid, the styloid process, the stylohyoid ligament,
and the small cornu of the hyoid bone. The great cornu and body of the hyoid
bone are developed from the third arch, while the fourth pharyngeal arch enters
merely into the formation of the soft parts of the neck, and does not give origin to
any special organ. The pharyngeal or branchial fissures are four in number, the
fourth being situated beneath or below the fourth arch; the first persists, though
only in a portion of its extent, forming the Eustachian tube, the meatus auditorius,
and the tympanic cavity. The other fissures are wholly closed by the sixth week.^
Face of an embryo of ?5 to 28 days. (Mag-
nified 15 times.) 1. Frontal prominence 2,
3. Eight and left olfactory fossse. 4. Inferior
maxillary tubercles, united in the middle line.
5. Superior maxillary tubercles. 6. Mouth or
fauces. 7. Second pharyngeal arch. 8. Third.
9. Fourth. 10. Primitive ocular vesicle. 11.
Primitive auditory vesicle.
' The relations of these pharyngeal arches to the cranial nerves are of the greatest interest in a
morphological point of view, but are hardiy yet quite settled. Prof. Parker has lately described
the ossification of the skull as proceeding from live arches — a prae oral and four pharyngeal or
post-oral ; the post-oral being the mandibular or inferior maxillary; the hyoid ; the thyro-hyoid ;
and the fourth, which, as above stated, has no remnant in the skeleton. The fifth cranial nerve,
the facial, and the glosso-pharyngeal, have definite relations to these arches ; each dividing so that
its anterior and posterior divisions embrace the cleft, or are distributed on the " bars," as Profes-
sor Parker calls them, which bound the cleft. 'Jlius the front division of the trigeminus is dis-
tributed in front of the buccal cleft on the prae-oral arch, and its posterior division on the first
pharyngeal or mandibular; the facial sends its anterior division — represented in the mature con-
dition by the chorda tympani— in front of the Eustachian fissure (the remains of the first cleft), to
the mandibular arch, while its descending branches go to the hyoid arch; the glosso-pharyngeal
110
GENERAL ANATOMY.
Development of the Palate. The buccal cavity is at first common to tlie mouth,
and nose. Then a lamella is given oft' from the superior maxillary tuberosity
on either side, which is directed horizontally inwards. These two palatine
lamellae meet in the median line, in front, about the eighth week, and by the
ninth week the septum should be complete. The superior maxillary bones pro-
per and the soft parts covering them, unite at an early period with the incisive
bone, and th^ median portion of the lower lip. The olfactory fossse open into
the upper (respiratory) portion of the cavity, forming the nostrils. The student
will notice that the various forms of hare-lip correspond to various interruptions
of the process of union ; thus the ordinary single hare-lip on one side of the
median line results from the mere absence of union on that side between the soft
parts which cover the incisive bone and those connected with the proper supe-
rior maxillary ; if this occurs on both sides, we have the simplest form of double
hare-lip ; if, besides this, the intermaxillary bone remains ununited, it usually is
carried forward at the end of the vomer, forming the double hare-lip, compli-
cated with projection of the intermaxillary bone ; if, added to this, the palatine
lamellae also remain ununited, we have the complete degree of fissured palate
and hare-lip. Fissure of the soft palate only, or of the soft and a portion of the
hard, represent various degrees of non-union of the palatine lamellae.
Fig. 79.
Development of the Nervous Centres. The medullary groove already described
(p. 98) presents about the third week three dilatations at its upper part, sepa-
rated by two constrictions, and at its posterior part
another dilatation called the rhomboidal sinus. Soon
afterwards the groove becomes a closed canal (medul-
lary canal), and a soft blastema is deposited in it,
which lines it, corresponding to its dilatations, and,
like it, assuming a tubular form. This is the rudiment
of the cerebro-spinal axis. As the embryo grows, its
cephalic part becomes more curved, and the three dila-
tations in the anterior end of the primitive cerebro-
spinal axis become vesicles distinctly separated from
each other (Fig. 79). These are the cerebral vesicles
— anterior, middle, and posterior. The anterior cere-
bral vesicle (situated at this period quite below the
middle vesicle) is the rudiment of the lateral and third
ventricles, and of the parts surrounding them — viz.,
the cerebral hemispheres, optic thalami, corpora
striata, corpus callosum, fornix, and all the parts
which form the floor of the third ventricle. The
middle vesicle represents the aqueduct of Sylvius with
the corpora quadrigemina, and the crura cerebri. The
posterior vesicle is developed into the fourth ventricle,
and its walls form the cerebellum, pons Varolii, me-
dulla oblongata, and parts in the floor of the fourth ventricle. The antero-pos-
terior fissure which indicates the division of the brain into two halves appears
early, and the primary anterior and posterior cerebral vesicles arc also soon
divided by a transverse fissure into two parts, so as to constitute five permanent
rudiments of the brain and medulla oblongata. The middle primary vesicle re-
mains undivided.
The anterior part of ihc anterior cerebral vesicle (Vordcrliirn, fore-brain, pros-
fjoes by its linirnal porlioii lo tli(' liyoi<] arcli, wliilc its pliaryiigcal partis distributed to llic tliyro-
hyoid.
'I'lu! theory is a beautiful one, and the method of inquiry most fruitful in promise for th(> higher
anatomy, which aims at uniting into one plan all the various forms of ova and the animals devel-
oped from them ; hut as yet it is hardly sufficiently established in fact lo be made a necessary
part of scliolastic teaching.
Longitudinal section of the head
of an embryo four weeks old, seen
from the inside. 1, ocular vesicle.
2, optic nerve flattened out. 3, fore
brain. 4, intermediary brain. 5,
middle brain. 6, hinder brain. 7,
after brain. 8, anterior portion of
the tentorium cerebelli. 9, its late-
ral portion intervening between
Nos. 4 and 5. 10, the pharyngeal
curve, bent into n, cul-de-sac . 11, the
auditory vesicle.
DEVELOPMENT OF THE BRAIN. lH
enceplialon) constitutes the cerebral liemisplieres, corpus callosum, corpora
striata, fornix, lateral ventricles, and olfactory nerves. These parts lie at first
quite covered and concealed by those formed from the middle vesicle, and by
the optic thalami, which, with the optic nerves, the third ventricle, and the parts
in its floor, are furnished by the posterior portion of the anterior vesicle (Zwisch-
enhirn, intermediary brain, thalamencephalon). By the third month, how-
ever, the hemispheres have risen above the optic thalami, and by the sixth
month above the cerebellum. Fissures are seen on the surface of the hemi-
sphere at the third month, but all except one disappear. This one persists, and
forms the fissure of Sylvius. The permanent fissures for the convolutions do
not form till about the seventh or eighth month. The middle cerebral vesicle
(Mittelhirn, middle brain, mesencephalon) is at first situated at the summit of
the angle shown on Fig. 79. Its surface, at first smooth, is soon divided by a
median and transverse groove into four tubercles (tubercula quadrigemina),
which are gradually covered in by the growth of the cerebral hemispheres. The
cavity diminishes as its walls thicken, and contracts to form the aqueduct of
Sylvius. The crura cerebri are also formed from this vesicle. The third pri-
mary cerebral vesicle is divided at an early period (between the ninth and
twelfth week) into two, the anterior part (Hinterhirn, hinder brain, epencephalon)
forming the cerebellum, and a membrane (membrana obturatrix), which closes
the upper part of the fourth ventricle, and which disappears as development
progresses ; its posterior part (Nachhirn, after-brain, metencephalon) forms the
medulla oblongata, with the restiform bodies and auditory nerves.^
The development of the pituitary bod}^ has of late received much attention, and
important questions of morphology are connected with this body. The descrip-
tion which is now accepted regards the pituitary body as the place of meeting of
the epiblast, hypoblast, and mesoblast at the extremity of the notochord and as
containing rudiments from each of these sources, or at least from the epiblast
and hypoblast, for the mesoblastic elements derived from the chorda dorsalis are
now said early to become displaced and to disappear.
At the point where the notochord terminates anteriorly the medullary layer
of the epiblast is reflected downwards to form a httle pouch (?/, Fig. 80) of nervous
substance, the infundibulum. At the same time the hypoblast passes upwards from
the pharynx, or upper end of the primitive intestine, to form, along with the
corneous layer of the epiblast, a similar pouch, which becomes closed and con-
verted into a closed glandular body, the glandular part of the pituitary body, or
hypophysis. The end of the notochord would lie at first between these two parts
of the pituitary body ; but it is believed that, as the hopophysis becomes closed
off and separated from the pharynx, the two parts of the pituitary body are
carried backwards and upwards from off the end of the notochord, so as to leave
the latter stranded as it were below the pituitary fossa. Others refer the hypo-
' The above forms a short abstract of the facts hitherto observed relative to the development
of the brain. But a very interesting series of lectures recently delivered by Mr. Callender at the
College of Surgeons gives a different account of the subject in some important particulars. Thus
Mr. Callender lays very great stress on the pineal and pituitary bodies in the course of the
development of the brain, classing them as the g'reat centres around which the organs are grouped,
and by which their position is determined. The pituitary body is anchored, as it were, at the
base of the brain, just in front of the spot where the notochord terminates anteriorly, while the
pineal body is anchored originally at the upper part of the future brain, near the bend of the head
(about No. 9, Fig. 79). 'Jlie two are connected together by a tract of tissue, and the pineal centre
gets covered in by the "mantles" or embryonal hemispheres, while the pituitary centre retains
nearly its relative position. Another important diflPcrence in Mr. Callender's from the previous
accounts is that he describes the permanent fissures in the lower part of the brain as appearing
much earlier than has been previously believed (as early as ten to twelve weeks), and says that
the obliteration of the.se fissures is apparent only, and due to their being covered in and concealed
by the tissue which is growing up to form the convoluted surface of the upper portion of the
hemispheres, but that they are really permanent, and that their identity with the fissures in the
base of the adult brain can be verified. For many interesting details as to the growth of various
parts of the brain we must refer to the published 'lectures in Brit. Med. Journ., June, 1874.
112
GENERAL ANATOMY.
pliysal part of tlie pituitary body to epiblastic elements derived from tlie buccal
part of the epiblast only, and so connect its development, not with the pharynx,
but with the mouth and the anterior portion of the skull. The question is an
obscure one, but its main interest is to remind the student that this peculiar
appendage to the brain forms, in aii early condition of the foetus, the meeting-
point of the portions of the ovum from which the nervous centres, the alimentary
canal, the mouth, and the base of the skull are developed; and that its develop-
ment has some connection, as yet imperfectly u.nderstood, with that of these, or
some of these, great sections of the body.
Fig. 80.
Vertical seotion of the hend in early embryos of the rabbit. Magnified (from Mihalkovlos). A, from an
embryo of five millimetres long. B, from an embryo of six millimetres long. C, vertical section of the
anterior end of the notochord and pituitary body, &c., from an embryo sixteen millimetres long, In A, the
faucial opening is still closed ; in B, it is formed ; c, anterior cerebral vesicle ; mc, meso-cerebrum ; mo, me-
dulla oblongata ; CO, corneous layer; in, medullary layer; z/, infundibulum ; am, amnion ; spe, spheno-
ethmoidal, be, central (dorsum sella;), and spo, spheno-occipital parts of the basis cranii ; li, heart ; /, anterior
extremity of primitive alimentary canal and opening (later) of the fauces ; i, cephalic portion of primitive
intestine ; tha, tlialamus ; jj', closed opening of the involuted ])art of the pituitary body [py) ; c/t, notochord ;
i>h, jjharynx.
AVlicn tlie medullary groove is closed, the foetal spinal marrow at first occu-
pies llic whole of the canal so formed. It presents at first a large central canal,
which gradually contracts, and in after life is no longer perceptible to the
eye, though it is still visible on microscopic sections (p. 68). After the fourth
month the s];)inal column begins to grow in length more rapidly than the
medulla, so that the latter no longer occupies the whole canal. The ganglia and
anterior roots of the nerves are jicrccptiblc at the fourth week, the posterior
roots at the sixth. The cord is composed at first entirely of uniform-looking
DEVELOPMENT OF THE EYE.
113
cells, wliicli soon separate into two layers, tlie inner of whicli forms tlie epithe-
lium of tlie central canal, while tlie outer forms the central gray substance of
the cord. The white columns are formed later ; their rudiments can be detected
about the fourth week, and some embryologists believe that they are developed
from the mesoblast. The central canal of the spinal cord is at first unclosed
behind, except by the epithelial layer, but at the age of nine weeks the medul-
lar v substance is united here also. The ganglia appear to be developed from
the protovertebral disks, and it is possible that the posterior roots also are ; the
anterior roots proceed from the medulla itself.^ The development of the nerves
has not yet been followed. The sympathetic can be seen as a knotted cord at
the end of the second month.
The cerebral and spinal membranes are also, according to KoUiker, a produc-
tion from the protovertebral disks, and are recognizable about the sixth week.
As the fissures separating the parts of the cerebro-
spinal axis appear, the membranes extend down them, Fig- 81.
and the pia mater passes into the cerebral ventricles, &
Bischofi", however, describes the pia mater and arach-
noid as developed from the cerebral vesicles, and
formed in the position which they permanently occupy.
Develop'ment of the Eye. The nervous elements and
the non-vascular parts of the eye are developed from
the epiblast, and the vascular portions from the meso-
blast, but the method of development is somewhat
complicated. The essential portions of the eye — i. e.
the retina and the parts immediately connected with
it— are an outgrowth from the rudimentary brain
(primitive ocular vesicle), and this outgrowth is met
by an ingrowth or covering from the common epider-
mic or corneous layer of the epiblast, out of which
the lens, conjunctiva, and corneal epithelium are de-
veloped.
The primitive ocular vesicle is at first an open cavity
communicating by a hollow stalk with the general
cavity of the Zwischenhirn, or intermediary brain —
the posterior division of the anterior cerebral vesicle.
As development advances the hollow stalk becomes
solid, and thus the optic nerve is formed, receiving,
however, in a way to be presently explained, mesoblastic elements for the forma-
tion of its central artery and connective tissue.
The lens is formed by a thickening of the epidermic layer, opposite to the
primitive ocular vesicle, by which that vesicle is at first depressed, and then
reversed in the manner indicated by the annexed figures ; so that the cavity of
the primitive ocular vesicle is finally obliterated. As this process takes place,
a secondary cavity (secondary ocular vesicle) is formed between the rudimentary
lens and the coats of the reversed primitive vesicle, and in this space the vitreous
humor is secreted.
The lens is at first a mere depression in the epidermic layer. When this is
closed the lens becomes a vesicle, formed of epithelial cells, which grow and fill
its cavity, becoming gradually transformed into fibres. It is at first surrounded
by a vascular membrane — the vascular capsule of the lens — which is connected
with the termination of the temporary artery (hyaloid) that forms the continua-
' It is now believed, chiefly on the authority of Mr. Balfour's researches on the development of
the elasniobranch fishes [Journ. of Anat. and PJu/s.), that the whole of these parts are probably
developed from the medullary groove, z. e. from the epiblast, thoii{j:h it is possible that the proto-
vertebral disks (?'. e. the mesoblast) may furnish the vessels and cellular tissue which are ia
connection with them.
8
Section of the medulla in the
cervical region, at six weeks,
magnified 50 diameters. 1, cen-
tral canal. 2, its epithelium. 3,
anterior gray matter. 4. poste-
riorgray matter. 5, anterior com-
missure. 6, posterior portion of
the canal, closed by the epithe-
lium only. 7, anterior column.
8, lateral column. 9, posterior
column. 10, anterior roots. 11,
posterior roots.
114
GENERAL ANATOMY.
tion of the central artery of tlie retina tlirougli tlie vitreous cliamber. Tliis
vascular capsule of the crystalline lens forms the niembrana pupillaris (to be
described hereafter), and also attaches the borders of the iris to the capsule of
the lens. It disappears about the seventh month.
Fi<r. 82.
Diagrara of development of the lens. ABO, different stages of development. 1, epidermic layer. 2, thick-
ening of this layer. 3, crystalline depression. 4, primitive ocular vesicle, its anterior part pushed back by the
crystalline depression. 5, posterior part of the primitive ocular vesicle, forming the external layer of the
secondary ocular vesicle. 6, point of separation between the lens and the epidermic layer. 7, cavity of the
secondary ocular vesicle, occupied by the vitreous.
These vascular elements are introduced into the globe of the eye from the
mesoblast, through a fissure which exists around the growing lens — the choroidal
fissure, or ocular cleft. The fold of mesoblast which projects through this fissure
is thus introduced behind the lens into the cavity of the secondary ocular vesicle
(or ocular cup as it is now called after Foster and Balfour), and it here furnishes
the vascular and fibrous elements of the iris and choroid, while its extremity is
believed to extend down the stalk of the primitive ocular vesicle and furnish
the arteria centralis retinse with the sheath and connective tissue of the optic
nerve.
The two layers of the primitive ocular vesicle are at first separated by a
space continuous with that of the original medullary cavity (or foetal ventricle),
but this space is afterwards obliterated. The
outer layer of the vesicle is chiefly pigmentary.
It lines the mesoblastic elements which are to
furnish the vascular choroid, and is developed
into the hexagonal pigment-layer, which func-
tionally forms part of the choroid, but is now
often described as belonging to the retina, on
account of this method of development. The
sclerotic and the fibrous or true cornea are also
developed out of this layer, though probably
with admixture of mesoblastic elements. In
fact, the mesoblast is now described by the most
recent authorities as the source of both mem-
branes. The inner layer gives origin to the
retina.
The eyelids are formed at the end of the third
month, as small cutaneous folds, which come
together in front of the globe and . cohere.
This union is broken up, and the eyelids sepa-
rate before the end of fcetal life.
Tlic lachrymal canal ap]"»ears to result from
the non-closure of a (issiirc which exists be-
tween the external nasal process and the
maxillary process (p. 100).
Diagrammatic sketch of a vertical longi-
tudinal section through the eyeball of a
human foetus of four weeks (after KOlli-
kcr). (Magnified 100 diameters.) The sec-
tion is a little to the side, so as to avoid
))assing throu'ih the ocular cleft, c, the
cuticle, where it becomes later the cornea ;
I, the lens; op, oj)tic nerve formed by the
jjodicle of the jirimary ojjtic vesicle; vp,
))rimary medullary cavity of the optic vesi-
cle ; p, the pigment-layer of the outer
wall ; r, tlie inner wall forming the retina ;
VH, secondary oi)tic vesicle containing the
rudiment of the vitreous humor.
Developmenl. 'if ihc Ear. The first rndimcnt of the car appears about the same
time as tliat (A tlio eye, in the fin-ni of a vesicle (primitive auditory vesicle.
DEVELOPMENT OF THE NOSE, ETC. 115
Figs. 78, 79, 11) situated close on the outside of the third cerebral vesicle, though
not communicating with it. It is formed by a depression of the epithelium over
the second pharyngeal arch, which becomes converted into a closed sac. From
this vesicle the internal ear is developed. The auditory nerve is described
either as a projection from the third cerebral vesicle, or as an independent
formation from the mesoblast which unites with both, and thus establishes a
communication between the cerebral and the auditory vesicles. The middle
ear and Eustachian tube constitute the remains of the first pharyngeal or bran-
chial cleft. The formation of the ossicles of the tympanum has been already
pointed out, viz., the incus and malleus from Meckel's cartilage, and the stapes,
with its muscle, from the second pharyngeal arch. These parts project into the
first pharyngeal cleft, which remains occupied by connective tissue during the
whole of foetal life, according to Kolliker. The membrana tympani forms across
the cleft, dividing it into an inner and outer portion. The pinna, or external
ear, is developed from the soft parts covering the first pharyngeal arch.
Developmeyit of the Nose. Two foss£e (olfactory fossas) have been already
spoken of, which are found below and in front of the ocular vesicles and the
upper maxillary projection (Fig. 78, 2, 3). They appear about the fourth week.
Their borders become prominent, and the fossse deepen, except at the lower
part, where they lead by a groove (olfactory groove) into the buccal cavity.
This groove is bounded by the internal and external nasal process. As the
superior maxillary projection increases, the olfactory groove is transformed into
a deep canal, the rudiment of the two superior meatus of the nose. As the
palatine septum is formed, the buccal cavity is divided into two parts, the upper
of which represents the inferior meatus of the nose, while the lower forms the
mouth. The soft ]3arts of the nose are formed from the coverings of the frontal
projection, and of the olfactory fossee. The nose is perceptible about the end of
the second month. The nostrils are at first closed by epithelium, but this dis-
appears about the fifth month.
The olfactory nerve, as above pointed out, is a prolongation, at first in the
form of a hollow stalk, from the anterior cerebral vesicle.
Development of the Teeth. This will be described in the body of the work.
Development of the Skin^ Glands, and Soft Parts. The epidermis is produced
from the external, the true skin from the middle, blastodermic layer (Fig. 6Q,
19, 20). About the fifth week the epidermis presents two layers, the deeper
one corresponding to the rete mucosum. The subcutaneous fat forms about the
fourth month, and the papilla of the true skin about the sixth. A considerable
desquamation of epidermis takes place during fostal life, and this desquamated
epidermis mixed with a sebaceous secretion constitutes the vernix caseosa, Avith
which the skin is smeared during the last three months of foetal life. The nails
are formed at the third month, and begin to project from the epidermis about
the sixth. The hairs appear between the third and fourth month in the form
of a depression of the deeper layer of the epithelium, which then becomes in-
verted by a projection from the papillary layer of the skin. The papilla grows
into the interior of the epithelial layer, and finally, about the fifth month, the
foetal hairs (lanugo) appear first on the head and then on the other parts. These
hairs drop off after birth, and give place to the permanent hairs. The sudo-
riferous and sebaceous glands are also formed from the epithelial layer about
the fifth and sixth month respectively. The mammary gland is also formed
from the deeper layer of the epithelium. Its first rudiment is seen about the
third month, in the form of a small projection, from which others radiate, and
which then give rise to the glandular follicles and ducts. The development of
the former, however, remains imperfect, except in the adult female, and espe-
cially after pregnancy. In all these glands the vessels, and probably also the
connective tissue, are furnished from tlie mesoblast.
116
GENERAL ANATOMY.
Development of the Limhs. The upper and lower limbs begin to project, as
buds, from tlie anterior and posterior part of the embryo about the fourth week.
These buds are formed by a projection of the somatopleure covered by the epi-
blast. The division of the terminal portion of the bud into fingers or toes is
early indicated, and soon a notch or constriction marks the future separation of
the hand or foot from the forearm. Next a similar groove appears at the site
of the elbow or knee. The indifferent tissue, or blastema, of which the whole
projection is at first composed, is differentiated into muscle and cartilage before
the appearance of any internal cleft for the joints between the chief bones.
The muscles become visible about the seventh or eighth week. The source of
their development is not completely determined for the muscles of the limbs.
The vertebral muscles appear to be developed from the " muscular laminae" of
the primitive vertebral disks (Fig. QQ^ 13), and the muscles of the neck and jaws,
as well as those which inclose the cavities of the thorax and abdomen, are also
formed from the same source. They do not meet in the middle line of the body
till about the fourth month. The cutaneous muscles are developed from the
cutaneous portion of the middle blastodermic layer.
Development of the Heart. The first trace of the heart is found about the tenth
or twelfth day, in the form of a mass of cells proceeding from the middle layer
of the blastodermic vesicle and the anterior wall of the intestinal cavity. It
soon forms a bent tube lying in front of the embryo, and only connected to it
by its vessels (Figs. 70, 75). The heart is situated at first at the anterior end of
the embryo, lying opposite the two last cerebral vesicles. As the head is
developed, the heart falls, as it were, backwards to the lower part of the neck,
and then to the thorax. It fills the whole thoracic cavity about the second
month. As the lungs and thoracic parietes form, the heart assumes its perma-
nent position. The tube is soon curved into the shape of the letter S, the
arterial part being situated above, in front and to the right, the venous below,
behind and to the left. Traces of the auricular appendages are early perceptible
on the venous part. Then the walls of the ventricular portion begin to thicken
in regard to the auricular part. The ventricle is separated by a constriction
from the dilated part above, which corre-
sponds to the aortic sinus or bulb (Fig. 85,
A, 1), and from the ]30sterior or auricular
dilatation. Then each of these three parts
becomes subdivided by a septum. After
the completion of the ventricular septum
the auricular is commenced. The septum
vcntriculorum is at first almost transverse,
and divides off a smaller portion (the right
ventricle) from the common cavity. This
septum is complete about the eighth week,
and then the interanricular begins to grow,
commencing from above and behind, and
coalescing with the edge of the interven-
tricular septum so as to leave an orifice
(auriculo-ventricular) on either side. The
auricular septum, however, is not com-
plete during foetal life, but leaves an aper-
ture (foramen ovale) by which the two
auricles communicate.
The heart is at first composed of a
mass of foetal cells, but its rhythmic con-
traf'tions can be observed even in this
condition before the development of any
Fijr. 84.
Various forms of motlior-cclls underj^oinp de-
vcloi)mcnt into bloodvessels, from the middle
layer of the cliick's blastoderm (Klein), o, lar^e
mother-cell vacuolated, forming the rudimentary
vessel, b, the wall of this cell formed of proto-
l>lasm, with nuclei embedded, and in some cases
more or less detached and jirojocting. c, processes
connected with neighboring cells, formed of the
common cellular substance of the germinal area.
(•/, blood-corpuscles. /, small mother-cells — vaciio-
lation commencing. Ji, mother-cell in whicli only
obscure granular matter Is found.
DEVELOPMENT OF BLOODVESSELS, 117
muscular fibres, and even, according to some autliors, before it is in connection
witli any vessels.
Development of Blood Corpuscles and Vessels. Tke earliest bloodvessels are
observed, as stated above, in tbe vascular area of tlie germinal membrane,
external to the body of the embryo. The indifferent cells of which the sub-
stance is composed are, according to Klein, " vacuolated," ^. e., they become
enlarged, their nuclei multiply, and, as they do so, an empty space is formed in
them, in which the nuclei become free and are converted into the blood-disks,
while the neighboring vacuolated bodies communicate together by processes in
which similar cells are either inclosed or formed, and thus a continuous branch-
ing tube is produced. The blood-globules are at first nucleated, and are larger
than the mature red globules, and in this and other respects more resemble the
white corpuscles ; but a red color is very early visible in them. After the liver
is formed, it seems the chief source from which immature blood-corpuscles are
furnished to the circulation, and later on the spleen and lymphatic glands take
up this function, and continue it after birth. The nucleated condition of the
red globules ceases before birth. The precise mode in which the nucleated white
corpuscle is converted into the non-nucleated red blood-globule, whether by a
change in the whole cell, or by the disappearance of the cell and persistence of
its nucleus, is not yet ascertained.
The vessels which are in communication with the foetal heart are as follows:
In its earliest state the circulation is exteraal to the embryo. This primitive
circulation appears about the fifteenth day, and lasts till the fifth week. It
consists of two arteries, the first aortic arches, which unite into a single artery,
Fig. 85.
Heart at the fifth week. A Opened from the abdominal aspect. 1. Arterial sinus. 2. Aortic arches uniting
behind to form the descending aorta. 3. Auricle. 4. Auriculo-ventricular orifice, 5. Commencing sei)tum
ventriculorum. 6. Ventricle. 7. Inferior vena cava. B. Posterior view of the same. 1. Trachea. 2. Lungs.
3. Ventricles. 4,5. Auricles. 6. Diaphragm. 7. Descending aorta. 8,9,10. Pneumogastric nerves and their
branches.
running down in front of the primitive vertebrse and in the walls of the intes-
tinal cavity, and joining in a single artery, which again divides into two primi-
tive aortse or vertebral arteries, and these give off five or six omphalomesenteric
arteries, which ramify in the germinal area, forming with their parent trunks a
close network, terminating in veins which converge towards a venous trunk,
the termi7ial sinus. This vessel surrounds the vascular portion of the germinal
area, but does not extend up to the anterior end of the embryo. It terminates
on either side in a vein called omphalomesenteric. The two omphalomesenteric
veins open into the auricular extremity of the heart. This primitive circulation
extends gradually from the germinal area over the whole of the umbilical vesicle,
and disappears as the latter becomes atrophied. In a more advanced state of
the embryo, the position of this first pair of aortic arches corresponds to the
first pharyngeal arch. ISText in succession, other pairs of arches are formed
behind the first^ (Fig. 86). The total number is five, but the whole five pairs
' The position of the first four of these aortic arches is behind the corresponding pharyngeal
arches, and that of the fifth behind the fourth pharyngeal cleft.
118
GENERAL ANATOMY,
do not exist together, for the first two have disappeared before the others are
formed. These two have no representatives in the permanent structures. The
third pair gives origin to the carotids, the fourth pair forms the innominata and
subclavian on the right, the arch of the aorta and subclavian on the left. The
fifth forms on the left side the pulmonary artery, the ductus arteriosus, and the
descending portion of the thoracic aorta. Its right branch disappears.^
The ascending portion of the arch of the aorta, and the root of the pulmonary
artery, are at first blended together in the common dilatation (aortic sinus),
which has been above spoken of as connected with the ventricular end of the
rudimentary heart (Fig. 85, A, 1). The septum which divides this common
artery into two begins to appear very early, even before the interventricular
septum. The formation of the permanent vessels is shown by the following
diagram : —
Fie-. 86.
!? II
m
'i^i
,j'
Diagram of the formation of the aortic arches and the large arteries. I. II. III. IV. V. First, second, third,
fourth, and fifth aortic arches. A. Common trunk from which the first pair spring; the place where the suc-
ceeding pairs are formed is indicated by dotted lines. B. Common trunk, with four arclies and a trace of the
fifth. C. Common trunk, with the three last pairs, the first two having been obliterated. D. The persistent
arteries, those which have disappeared being indicated by dotted lines. 1. Common arterial trunk. 2. Tho-
racic aorta. 3. Eight branch of the common trunk, which is only temporary. 4. Left branch, permanent. 5.
Axillary artery. 0. Vertebral. 7, 8. Subclavian. 9. Common carotid. 10. External; and 11. Internal carotid.
12 Aorta. 13. Pulmonary artery. 14,15. Eight and left pulmonary arteries.
The descending aorta appears to be the remnant of the artery formed by the
union of the two primitive aortte (Fig. 86). The omphalomesenteric arteries
which spring from these latter, all disappear except one, which remains as the
superior mesenteric artery. When the activity of the umbilical vesicle and
omphalomesenteric duct ceases, the allantois takes up the function of conducting
the vessels which are to nourish the embryo, and now the umbilical arteries
extend along the allantois to the chorion, and grow in size as the umbilical cord
and placenta are formed. The umbilical arteries are at first the terminations
of the two principal aortte, but when these vessels are united into one, the
umbilical arteries appear as branches, and the aorta itself ends in a caudal
prolongation, which afterwards becomes the middle sacral. The common and
internal iliac arteries are the only permanent remains of the umbilical arteries
(see Internal iliac artery).
Veins. The primitive venous circulation has been described above, the two
omphalomesenteric veins opening by a common trunk into the lower end of the
tube which represents the heart. The next state of the venous circulation is,
that at about four weeks there is found a single vein lying behind the intestinal
cavity (not in front of it, as the temporary omphalomesenteric veins do), and
receiving the trunk vein from the intestine (mesenteric). Two umbihcal veins
are early formed, and open together into the common trunk of the()m])liaki-
' 'I'lic rclatioiiH of llio ro(;nrrent bniiicli of tlio piioinnoficnstrie nerve arc of iiifci'ost in rerorcnce
\(> llii' fifth aortic, or liraiicliial arcli. If we assiiino tliat in tlie fa^tiis tlie rccurront nerve ivS dc-
taclii'd from its ])areiit truni< by tlic projection of tlie fiflli arcli, tliis would account for its situation
on llic left side in the adulf, ciirvin'r as it does round the ductus arteriosus, wliich is the remnant
oflli:!! iirfli. Oil till! riuiit, si(l(^ the disappearance of the fifth arch hrinirs it into relation with
I III' rmutli, and accordingly in the adult it curves round the subclavian, which is the remnant of
that arch.
DEVELOPMENT OF THE VEINS.
119
mesenteric vein. They receive branches from the allantois and anterior surface
of the embryo. The right vein soon disappears; the left umbihcal vein, on the
contrary, grows till it becomes the trunk vessel into which the omphalomesen-
teric vein and its mesenteric branch appear to open. Next the liver begins to
be formed around the umbilical vein, and then this vein sends branches into
that gland (afferent veins) which afterwards become the portal veins in the
interior of the liver, and which give origin to other veins (efferent), which return
the blood from the liver, and form afterwards the hepatic veins. The portion
of the umbilical vein between the giving off of the future portal vessels and the
reception of the hepatic, forms the ductus venosus. The mesenteric vein com-
municates at first with the omphalomesenteric ; when the veins of the liver are
formed, the omphalomesenteric is transferred from the umbilical vein to the right
afferent hepatic. A portion of it persists and forms the trunk of the portal vein.
The systemic veins are developed from four trunk veins, two on either side,
above and below, which appear before the formation of the allantois or the um-
bilical vessels. These unite into one canal on either side (sinuses of Cuvier),
which open into the common trunk of the omphalomesenteric veins, and so into
the auricular portion of the rudimentary heart. These four primitive veins lie,
two of them in front, the anterior cardinal, or jugular veins, and the other two
behind, the posterior cardinal veins. As the umi3ilical vein increases, and the
omphalomesenteric diminishes in volume, the sinuses of Cuvier are transferred
to the former vein, and when the inferior cava is formed and the umbilical vein
becomes merely its tributary, the sinuses of Cuvier open into the inferior vena
Fig. 87.
Diagram of the formation of the main systemic veins. A, heart and venous system at the period when there
are two venas cavee sujjeriores, posterior view. 1, left superior cava. 2, right superior cava. 3, inferior cava.
4, left inferior cardinal. 5, right inferior cardinal. 6, right jugular. 7, anastomosing branch between the jugu-
lars (left innominate). 8, subclavian. 9, internal jugular. 10, external jugular. 11, middle obliterated portion
of the posterior cardinal veins. 12, newly formed posterior vertebral veins. 13, anastomosis between the two
vertebrals — trunk of small azygos. 14, iliac veins, proceeding from anastomosis between the inferior cava
and posterior cardinals. 15, crural. 16, hypogastric — originally the distal ends of the cardinals. B. heart and
permanent veins, posterior view. 1, obliterated left superior cava. 6, right innominate. 7, left innominate.
8, subclavian. 10, jugular. 13, trunk of the small azygos. 17, coronary sinus receiving the coronary vein. 18,
superior intercostal. 19, superior small azygos. 20, inferior small azygos.
cava.
At a later period the portion of the vena cava inferior, between the
opening of the sinuses of Cuvier and the auricle, disappears, and then the auricle
receives three veins — viz., the inferior cava, and the two sinuses of Cuvier, which
are now called right and left superior vena cava (Fig. 87). The superior car-
120 GENERAL ANATOMY.
dinal, or jugular veins, wliicli form tlie upper brandies of tlie sinuses of Cuvier
on either side, unite about the second montli bj a transverse anastomosing
branch. The left superior vena cava assumes an oblique position, and empties
itself into the lower and left end of the auricle. Finally, its trunk disappears,
while its orifice is transformed into the coronary sinus, in whicn the great cardiac
vein opens.^ The right sinus of Cuvier, or superior vena cava, persists ; the
transverse anastomosing branch between the two jugulars becomes the left
innominate vein, and the end of the right jugular the right innominate. The
venous circulation in the lower part of the embryo is at first carried on by the
inferior cardinal veins, which return the blood from the Wolffian bodies, and
receive branches corresponding to the intercostal, lumbar, and crural veins.
Between the fourth and fifth week, the inferior vena cava begins to appear in
the form of a vessel which passes upwards behind the liver and between the two
Wolffian bodies. It anastomoses below with the two cardinal veins, and with
the crural veins, which gradually come to open into it.
The middle part of the cardinal veins disappears ; their distal extremities
persist as the hypogastric veins, which open along with the crural into the vena
cava, forming the iliac and other veins of the lower extremities. The termina-
tion of each cardinal vein above, in the sinus of Cuvier, or superior cava, also
persists. The central atrophied portion of the cardinal veins is replaced by a
vein on either side, called posterior vertebral, which receive the intercostal and
lumbar veins, and are soon united by an oblique anastomosing branch. The
right vertebral vein, together with the persistent termination of the right car-
dinal vein, forms the great azygos vein. The distal portion of the left vertebral
vein, with the oblique anastomosing branch, forms the small azygos; and the
upper part of the left vertebral, with the persistent termination of the left car-
dinal, forms the left superior intercostal vein.
The " Foetal Circulation" will be described hereafter. See Fig. 464.
Development of the Alimentary Canal. The development of the intestinal cavity
is, as shown above (p. 100), one of the earliest phenomena of embryonic life.
This original intestine is closed at either end, all the three blastodermic layers
being here in contact, and is at first in free communication with the umbilical
vesicle (Fig. 88). It is divided into three parts: the anterior or cephalic portion
of the primitive intestine, the middle or abdominal, and the posterior or pelvic.
From the first are formed the pharynx and oesophagus, with the trachea and
lungs; from the second, the stomach, small intestine and large intestine, as far
as the upper part of the rectum; from the third, the middle third of the rectum.
The buccal cavity on the one hand, and the lower portion of the rectum on the
other, are separate productions from the middle and external layers of the blas-
todermic membrane, and do not communicate with the common cavity till a
later period. The permanence of the foetal septum in either case constitutes a
well-known deformity — imperforate oesophagus or imperforate rectum, as the
case may be. The anal cavity is at first common to the urogenital and the
digestive organs.
The development of the palate has been spoken of above.
The tongue appears about the fifth week as a small elevation, beliiud llic
' Mr. Miirsliiill liiis ]K)iiitf'(l oiil tluit in tlu> iuliilt tlio rotiiains of (lie ol)lilorii1o(l loft superior
cava can be distiiifriii.shed as a cord, or sometimes a small vein Avhich passes down in front of llie
rifrlit auricle to the coronary sinus, and tliat tlie projection of I his cord forms a fold of the serous
pericardium f)ver llie root, of the left lunij, which from that circumstance he luis named " the vest?'-
(jial fold." And hi', has figured a case in which the left superior vena cava remained pervious,
forming an anastomosis l)etween the united left subclavian and internal jugular veins, and the
coronary sinus, the left brachio-cciphalic Ixnng reduced to a small anastomosing branch. 'I'he
abnormal vein ran along the vestigial fold, receiving the left superior intercostal vein (see the
figure in Quain's " Anatomy," vol. ii. p. 798).
DEVELOPMENT OF ALIMENTARY CANAL.
121
inferior maxillary arcli, to which is imited another projection from the second
pharyngeal arch. The epithelial layer is furnished by the external blastodermic
membrane.
The tonsils appear about the fourth month.
The middle portion of the primitive intestine is at first a groove communi-
cating freely with the umbilical vesicle. The groove is early converted into a
straight tube, which, however, is still open where it communicates with the
umbilical vesicle. This opening contracts more and more as the embryo
advances in development, and as the importance of the vitelline duct and yolk-
sac diminishes, until at length all traces of the latter structures disappear in the
normal condition. Abnormally, however, a diverticulum is sometimes formed
Fig. 88.
1 u
Early form of the alimentary canal (from Kolliker after Bischoff). In A a front view, and in B an antero-
posterior section, are represented, a, four jsharyngeal or visceral plates; h, the pharynx; c, c, the commencing
lungs; d, the stomach ;/,/, the diverticula connected vt'itli the formation of the liver; g', the yolk-sac into
which the middle intestinal groove opens ; h, the posterior part of the intestine.
from the small intestine near the caecum, which is regarded with great proba-
bility as a pervious portion of the omphalomesenteric duct, and which has been
found passing into the umbilical cord. The peritoneal folds are furnished by the
splanchnopleural layer of the mesoblast, coated by the epithelial layer of hypo-
blast. In the cephalic portion of the primitive intestine these folds remain sepa-
rate on the two sides to form the pleurge, and a central portion is divided off from
them to cover the heart and form the pericardium. While the abdominal intes-
tine is in the grooved condition, the two peritoneal cavities are also separate, but
they early communicate together.
As the tube of the abdominal intestine grows in length, it leaves the vertebral
column in the middle, and forms a curve attached to that column by the mesen-
tery. A portion of the intestine above this mesentery dilates into the stomach,
which gradually also acquires a mesentery of its own ; the rest remains attached
to the spine, and forms the duodenum. The curve of the intestine appears as it
were drawn out from the body by its attachment to the vitelline duct, and lies
external to the parietes, and in the umbilical cord, until the end of the third
month, when it passes back again into the abdomen. While still forming a
portion of the cord, the intestine begins to be distinguished into large and small; for
the anterior or upper part, corresponding to the small intestine, begins to assume
a convoluted arrangement about the eighth week, whilst the lower part, which
had been posterior, passes to the front and right side of the other, and becomes
dilated at a short distance from the insertion of the vitelline duct, to form the
122 GENERAL ANATOMY.
rudiment of tlae caecum. Wlien tlic intestine lies wliolly in tlie "belly, tlie cnrve
of the large intestine begins rapidly to form ; but tbe cfecnm lies for some time
in tlie middle line, and tlie ascending colon is not fully formed till tlie sixth
month.
The source of each layer of the intestine, and the closure of the omphalo-
mesenteric or vitelline duct, have already been referred to (pp. 98, 100).
The liver appears after the Wolffian bodies, about the third week, in the form
of two depressions formed by the epithelial and fibro-intestinal layers of the blasto-
dermic membrane, and projecting from the intestine at the part which afterwards
forms the duodenum. These depressions are developed into the right and left
lobes. They grow very rapidly around the omphalomesenteric vein, from which
they receive the branches enumerated on p. 119, and about the third month the
liver almost fills the abdominal cavity. From this period the relative develop-
ment of the liver is less active, more especially that of the left lobe, which now
becomes smaller than the right ; but the liver remains up to the end of foetal life
relatively larger than in the adult.
The gall-bladder appears about the second month, and bile is detected in the
intestine in the third month.
The pancreas is also an early formation, being far advanced in the second
month. It, as well as the other salivary glands, which appear about the same
period, originates in a projection from the epithelial layer, which afterwards forms
a cavity, from the ramifications of which the lobules of the gland are formed.
In the development both of the liver and pancreas it seems to be admitted
that the epithelial lining of the duct-passages is furnished by the hypoblast, and
the vessels by the mesoblast ; but authorities difier as to the mode of' formation
of the parenchyma (cellular tissue, &c.), whether this is entirely mesoblastic or
is contributed by both membranes.
The spleen is regarded as formed entirely from the mesoblast, proceeding,
according to Miiller (Strieker's "Handbook," vol. i.), in all vertebrata from a
segment of the peritoneum.
Development of the Respiratory Organs. The lungs appear somewhat later than
the liver. They are developed from a small cul-de-sac^ which is formed on either
side as a projection from the epithelial and fibrous laminae of the intestine.
During the fourth week these depressions are found on either side, opening
freely into the pharynx, and from the original pouches other secondary pouches
are given off, so that by the eighth week the form of the lobes of the lungs
may be made out. The two primary pouches have a common pedicle of com-
munication with the pharynx. This is developed into the trachea (Fig. 85), the
cartilaginous rings of which are perceptible about the seventh week. The parts
which afterwards form the larynx are recognized as early as the sixth week,
viz. : a projection on either side of the pharyngeal opening, the rudiment of the
arytenoid cartilages, and a transverse elevation from the third pharyngeal arch,
which afterwards becomes the epiglottis : the vocal cords and ventricles of the
larynx arc seen about the fourth month. The traces of the diaphragm appear
early, in the form of a fine membrane, sej^arating the lungs from the Wolffian
bodies, the stomach and liver. As the diaphragm extends forwards from the
vertcljral column, with the muscular plates of which its dcvelo}nnent is proba-
bly connected, it separates the common pleuro-peritoneal cavity into two parts,
a thoracic and abdominal. The membrane which linos this common cavity has
been traced, above, as derived from the splanchnopleure, with an epithelial
liiiiiiji' of 1i v'))oblast.
JJevelo'praent of the Genitn-urinar]/ Orgavs. Tlie internal gcnito-urinary organs
appear to be entirely of mesoblastic; origin, and ]Kn-ha-ps the easiest way of
rondf^ring their formation intelligible is to commence with the descri})tion of the
Wolffian body.
WOLFFIAN BODY.
123
Tlie Wolffian body, or primordial kidney, is perceptible about tlie tliird week,
forming a mass of cells wliicli soon give rise to a hollow organ, situated on
Fis:. 89.
Fig. 90.
Enlarged view from before of the left Wolffian body before the establishment of the distinction of sex (from
Farre after Kobelt). a, a, b, d, tubular structure of the Wolffian body ; e, Wolffian duct ;/, its upper extremity ;
g, its termination in x, the urogenital sinus ; h, the duct of Miiller ; i, its upper still closed extremity; k, its
lower end terminating in the urogenital sinus; Z, the mass of blastema for the reproductive organ, ovary or
testicle.
eitlier side of tlie primitive vertebra, and extending from tlie lieart to the lower
end of tlie embryo, terminating above in a cul-de-sac and opening below into
tlie urogenital sinus. The structure of the
Wolffian body is in many respects analogous
to that of the permanent kidney. It is com-
posed partly of an excretory canal or duct,
into which open numerous "conduits," recti-
linear at first, but afterwards tortuous, and
partly of a cellular or glandular structure, in
which Malpighian tufts are found. It is
fixed to the diaphragm by a superior liga-
ment, and to the spinal column by an inferior
or lumbar ligament. Its ofiice is the same as
that of the kidneysj viz., to secrete fluid con-
taining urea, which accumulates in the
bladder. When the permanent kidneys are
formed, the greater part of the Wolffian
body disappears. The rest takes part in the
formation of the genital organs.
The activity of function of the Wolffian
bodies is very transitory, and they attain
their highest development by the sixth
week, after which time they begin to de-
crease in size, and have nearly disappeared
by the end of the third month.
The duct of the Wolfiian body is the part
first formed, and it makes its appearance in
a mass of blastema which lies below the
heart and behind the common plero-perito-
neal Cavity, proceeding from the mesoblast
at the point of the separation of its two
layers. As this mass is situated below the
epiblast (reflected from the medullary cavity) ^,^^ ^,^,„igj^„ ^j^^^t, j„ ^,_ ^^^ g^^i^ai cord ; ug,
at the side of the protOVertebrEe and above sinus urogenltalls ; i, lower part of the Intes-
the common pleuro-peritoneal cavity, it has ^i»e ; a, common opening of the intestine and
been named "the intermediate cell-mass." ' ' ' ' * ^•-'-'^ °=
In this mass, first the Wolffian duct is
hollowed out, then the tubes of the Wolf-
fian body begin to form as branches of the duct, next occurs a thickening or
ridge — the Wolffian ridge or germ ejpithelium — and next a groove which is
Diagram of the primitive urogenital organs
in the embryo previous to sexual distinction.
The parts are shown chiefly in profile, but the
Miillerian and Wolffian ducts are seen from the
front. 3, ureter ; 4, urinary bladder ; 5, urachus ;
ot, the mass of blastema from which ovary or
testicle is afterwards formed ; W, left Wolffian
body; Xi ^ part at the apex from which the
coni vasculosi are afterwards developed ; iv,w,
right and left Wolffian ducts; m, m, right and
left Miillerian ducts uniting together and with
urogenital sinus; cp, elevation which becomes
clitoris or penis ; Is, ridge from which the labia
majora or scrotum are formed.
124 GENERAL ANATOMY.
converted into a duct, lying internal to tlie Wolffian dnct, and called the duct
of Miiller. The Wolffian and MUllerian ducts open (along with the ureter when
formed) into the common urogenital sinus, or cloaca, which is the termination
of the common intestinal cavity, and into which the allantois also opens in front.
As the allantois expands into the urinary bladder this common cavity is divided
into two by a septum, to form the bladder in front and the rectum behind. The
Wolffian and Mullerian ducts are soon connected by cellular substance into a
single mass — the genital cord — in which the Wolffian ducts lie side by side in
front, and the ducts of Miiller behind, at first separate, but later on coalescing.
The allantois communicates at first with the lower part of the primitive intes-
tine by a canal — -the urachus. After the second month the lower part of the
urachus dilates, so as to form the bladder, which then communicates above with
the cavity of the urachus, and below with the rectum, by a canal of commu-
nication which is afterwards transformed into the urethra. The urachus is
obliterated before the termination of foetal life ; but the cord formed by its
obliteration is perceptible throughout life, passing from the upper part of the
bladder to the umbilicus, and occasionally remains patent during life, consti-
tuting a well-known deformity. The permanent kidneys are almost, if not
entirely, independent of the Wolffian bodies or primordial kidneys in their
development, though they originate in the same mass of blastema, the interme-
diate cell-mass behind the Wolffian body. As their distance from the bladder
increases, the ureters become developed, and the simple culs-de-sac in which the
foetal kidneys commence divide and subdivide so as to form lobulated organs
provided with calices in their interior. This lobulation is perceptible for some
time after birth.
The mode of development of the ureters is not exactly known. Some embry-
ologists describe them as extending gradually from the allantois upwards, so
that the proper tissue of the kidney would be developed upon projections, or
buds, out of the upper ends of the ureters. Others describe the ureter as an
offset from the upper part of the Wolffian duct. Others teach that the kidney
tissue is formed before the ureter, and that the ducts of the former are hollowed
out and open into the latter. Others, again, believe that the whole organ
(kidney and ureter) is laid down in the same mass of blastema, which is at first
solid, and that the various ducts or hollow spaces are formed in each part simul-
taneously. What is admitted is that the solid blastema in which the kidney
commences comes to be arranged in a series of club-shaped bodies, which have
their larger ends directed towards the hilum, and that these afterwards become
hollow and open into the ureter, which has then also assumed the condition of
a tube, communicating with the part of the allantois afterwards converted into
the bladder. As the future uriniferous tubes grow, they become convoluted, so
that the whole substance of the kidney seems at first to consist of cortical sub-
stance. Then the ends of the tubes become straight, and the pj^ramidal struc-
ture is developed.
The suprarenal bodies are developed from the same mass as the kidney, and
arc said at first to form a single organ in the middle line. "Kolliker has
observed them in close connection with the substance in which the large sym-
])athetic plexus of the abdomen is produced, but it is not ascertained that they
have a common origin." They are at first larger than the kidneys, but become
cfjual in size about the tenth week, and from that time decrease relatively to
the kidney, though they remain throughout foetal life much larger in pro])ortion
than in the adult. Meckel gives the proportion as 1 to 8 at birth, and 1 to 22
in mature life.
We must now follow the development of the genital organs in each sex.
Fcni/de Orfjans. The ovaries take their origin in the ridge of germ epithe-
lium which has been spoken of above as making its appearance in the interme-
diate cell-mass; from the cells of which c])ithelium, according to the most recent
observations, the ova take their origin. These ova are inclosed or encapsuled in
DEVELOPMENT OF GENITAL ORGANS,
125
a fibrous stroma, developed from the deeper blastema of the same cell-mass, or,
according to earlier observers, from a part of the Wolffian body. According to
the latest account the only remains of the Wolf&an body in the complete condi-
Fig. 91.
Adult ovary, parovarium, and Falloinan tube (from Farre, after Kobelt). a, a, Epoophoron (parovarium)
formed from the upper part of the Wolffian body: ft, remains of the uppermost tubes sometimes forming hyda-
tids ; e, middle set of tubes ; d, some lower atrophied tubes ; e, atrophied remains of the Wolffian duct ; /, the
terminal bulb or hydatid; A, the Fallopian tube, originally the duct of Miiller ; , hydatid attached to the
extremity; /, the ovary.
tion of the female organs are two rndimentarj^ or vestigial structures which can
be found in the round ligament near the ovary on careful search — the parova-
rium, or organ of Eosenmiiller, and the epoophoron. The organ of Eosenmiiller
consists of a number of tubes which converge to a transverse portion (the epoo-
Fig. 92.
Female genital organs of the embryo, with the remains of the Wolffian bodies (after J. Miiller). A, from a
fcEtal sheep ; a, the kidneys ; 6, the ureters ; e, the ovaries ; d, remains of Wolffian bodies ; f. Fallopian tubes ;
/, their abdominal openings; g, their union in the body of the uterus. B, more advanced from a foetal deer;
o, body of the uterus ; b, cornua ; c, tubes ; d, ovaries; e, remains of Wolffian bodies. C, still more advanced
from the human fcetus of three months ; a, the body of the uterus ; ft, the round ligament ; c, the Fallopian
tubes ; d, the ovaries : e, remains of the Wolffian bodies.
phoron), and this is sometimes prolonged into a distinct duct running trans-
versely— the duct of Gaertner- — -which is much more conspicuous and extends
further in some of the lower animals. This is the remains of the Wolffian duct.
The Fallopian tube is formed by the portion of the duct of Miiller, which lies
126 GENERAL ANATOMY.
above tlie lumbar ligament of tlie Wolffian body. Tliis duct is at first com-
pletely closed, and its closed extremity remains permanent, forming a small
cystic body attached to the fimbriated end of tlie Fallopian tube, and called tlie
"hydatid of Morgagni." Below this, a cleft forms in the duct, and is developed
into the fimbriated opening of the Fallopian tube.
Below this portion of the duct of Midler, that body on either side, and the
ducts of the Wolffian body, are united together in a structure called the "genital
cord," in which the two Miillerian ducts approach each other, lying side by
side and finally coalescing to form the cavity of the vagina and .uterus. This
coalescence commences in the middle, corresponding to the body of the uterus.
The upper parts of the Miillerian ducts in the genital cord constitute the cornua
of the uterus, little developed in the human species. The only remains of the
Wolffian body consist in the organ of Eosenmliller.
About the fifth month an annular constriction marks the position of the neck
of the uterus, and after the sixth month the walls of the uterus begin to thicken.
The round ligament is derived from the lumbar ligament of the Wolffian body,
the peritoneum constitutes the broad ligaments, the superior ligament of the
Wolffian body disappears with that structure.
Male Organs. The testicles are developed from the intermediate cell-mass
(genital gland of the older embryologists) behind and to the inside of the Wolffian
bodies, from which the essential parts of the gland, the tubuli seminiferi, and
their contents take origin.
The tubuli seminiferi are early visible, being at first short and straight, and
then gradually assume a coiled arrangement. The tunica albuginea is formed
about the third month.
The Miillerian ducts disappear in the male sex, with the exception of their
lower ends. These unite in the middle line, and open by a common orifice into
the urogenital sinus. This constitutes the utriculus liominis or sinus j^rostatdcus.
Occasionally, however, the upper end of the duct of Miiller remains visible in
the male as it does in the female, constituting the little pedunculated body,
called the hydatid of Morgagni, sometimes found in the neighborhood of the
epididymis,^ between the testis and globus major.
The head of the epididymis, its canal, the vas deferens and ejaculatory duct,
are formed from the canals and from the duct of the Wolffian body.
The remains of the Wolffian bodies also form the vas aberrans and a structure
described by Girald^s,^ and called after him "the organ of Girald^s," which bears
a good deal of resemblance to the organ of Eosenmiiller in the other sex. It
consists of a number of convoluted tubules lying in the cellular tissue in front
of the cord and close to the head of the epididymis.
The descent of the testis and the formation of the gubernaculum are described
in the body of the work.
The External organs of generation^ like the internal, pass through a stage in
which there is no distinction of sex (Fig. 93, II., III.). We must therefore first
describe this stage, and then folloAV the development of the female and male
organs respectively.
As stated above, the anal depression at an early period is formed by an involu-
tion of the external epithelium apart from the intestine, which is still closed at
its lower end. Wlicn the septum between the two opens, which is about the
fourth week, the u radius in front and the intestine behind both communicate
with the cloaca. About the second month a transverse division (the perineum)
begins to form, and divides the cloaca into the anal cavity behind, and the uro-
genital sinus in front. In the sixth week a tubercle, the genital tubercle, is formed
in front of the clojica-, and this is soon surrounded by two folds of skin, the
' Mr. Osborii, in tlio St,. Tliomas'K ll()s]iil;il Rcporls, ]H7."), lia.s wriltcii an inti'iTstiiig i)apcr
pointing'' out llin probaltlc coimectioii bolwoeii tliis i'a'tal structure and one form of hydrocele.
2 Juurn. de Fhys., IbGi.
DEVELOPMENT OF GENITAL ORGANS.
127
genital folds. Towards tlie end of the second montli tlie tubercle presents, on
its lower aspect, a groove, tlie genital furrow^ turned towards tlie cloaca. All
these parts are well developed at the period shown by No. III. of the following
diagrams, where the anus is separated from the urogenital sinus, yet no distinc-
tion of sex is possible.
Development of the external genital organs. Indifferent type, I. II. III. Female. A B, at the middle of the
fifth month. O, at the beginning of the sixth. Male. A', at the beginning of the fourth month. B', at the
middle of the fourth month. C, at the end of the fourth month. 1. Cloaca. 2. Genital tubercle. 3. G-lans
penis or clitoridis. 4. Genital furrow. 5. External genital folds (labia majora or scrotum). 6. Umbilical cord.
7. Anus. 8. Caudal extremity and coccygeal tubercle. 9. Labia minora. 10. Urogenital sinus. 11. FrEenum
clitoridis. 12. Preputium penis or clitoridis. 33. Opening of the urethra. 14. Opening of the vagina. 15.
Hymen. 16. Scrotal raph^.
Female Organs (Fig. 93, A, B, C). The female organs are developed by an
easy transition from the above form. The urogenital sinus persists as the vesti-
128 GENERAL ANATOMY.
bule of the vagina, and forms a single tube with the upper part of the vagina,
which we have already seen developed from the united Mullerian ducts. The
genital tubercle forms the clitoris, the genital folds the labia majora, the lips of
the genital furrow the labia minora, the genital furrow remaining open except
below, where it unites with the perineum, constituting the raphe.
Male Organs. In the male the changes are greater from the indifferent type.
The genital tubercle is developed into the penis, the gians appearing in the third
month, the prepuce and corpora cavernosa in the fourth. The genital furrow
closes, and thus forms a canal, the spongy portion of the urethra. The urogenital
sinus becomes elongated, and forms the prostatic and membranous urethra. The
genital folds unite in the middle line, to form the scrotum, at about the same
time as the genital furrow closes, viz., between the third and fourth month.
The following table is translated from the work of Beaunis and Bouchard,
with some ver}^ unimportant alterations.^ It will serve to present a resume of
the above facts in an easily accessible form.
' It will be noticed that, the time assigned in this table for the appearance of the first rudiment
of some of tlie bones [e.g the ilium), varies in some cases from that assigned on p. 55. This is a
point on which anatomists differ, and which probably varies in different cases.
CHEOIi^OLOGIOAL TABLE
OF
THE DEYELOPMEE'T OF THE ECETIJS.
(From Beaunis axd Bouchard.)
End of second week. — Formation of the amnion and umbilical vesicle. Chorda dorsalis and
medullary groove. Heart.
Beginning of third week.- — The vitelline membrane has entirely disappeared. Protovertebral
disks. First pharyngeal arch. Buccal depression. Primitive circulation.
End of third lueek. The allantois and Wolffian body appear. The amnion is closed. Cerebral
vesicles. Primitive ocular and auditory vesicles. Coalescence of the inferior maxillary
protuberances. Liver. Formation of the three last pharyngeal arches.
Fourth weeli. — The umbilical vesicle has attained its full development. Projection of the caudal
extremity. Projection of the upper and lower limbs. Cloacal aperture. The heart sepa-
rates into a right and left heart. Spinal ganglia and anterior roots. Olfactory fossas.
Lungs. Pancreas.
Fifth week. — Vascularity of the allantois in its whole extent. First trace of hands and feet.
The primitive aorta divides into primitive aorta and pulmonary artery. Conduit of Muller
and genital gland. Ossification of clavicle and lower jaw. Cartilage of Meckel.
Sixth iveek. — The activity of the umbilical vesicle ceases The pharyngeal clefts disappear.
'J'he vertebral column, primitive cranium, and ribs assume the cartilaginous condition.
Posterior roots of the nerves. Membranes of the nervous centres. Bladder. Kidneys.
Tongue. Larynx. Thyroid gland. Germs of teeth. Genital tubercle and folds.
Seventh loeek. — The muscles begin to be perceptible. Points of ossification of the ribs, scapula,
shafts of humerus, femur, tibia, intermaxillary bone, palate, upper jaw (its first four points).
Eighth '^(;ee^^— Distinction of arm and forearm, and of thigh and leg. Appearance of the inter-
digital clefts. Capsule of the lens and pupillary membrane. Completion of the interven-
tricular and commencement of the interauricular septum. Salivary glands. Spleen. Su-
prarenal capsules. The larynx begins to become cartilaginous. All the vertebral bodies
are cartilaginous. Points of ossification for the ulna, radius, fibula, and ilium. The two
halves of the bony palate unite. Sympathetic nerve.
Ninth iveek. — Corpus striatum. Pericardium. Distinction between ovary and testicle. Forma-
tion of the genital furrow. Osseous nuclei of vertebral bodies and arches, frontal, vomer,
malar bone, shafts of metacarpal bones, metatarsal bones and phalanges. The union of the
hard palate is completed. Gall-bladder.
Third month. — Formation of the fcetal placenta. The projection of the caudal extremity disap-
pears. Tt is possible to distinguish the male and female organs at the commencement of the
third month. The cloacal aperture divided into two parts. 'J'he cartilaginous arches on
the dorsal region of the spine close. Points of ossification for the occipital, sphenoid, os
unguis, nasal bones, squamous portion of temporal and ischium. Orbital centre of superior
maxillary bone. Commencement of formation of maxillary sinus. Pons Varolii. Fissure
of Sylvius. Formation of eyelids and of hairs and of nails. Mammary gland. Epiglottis.
Union of the testicle with the canals of the Wolffian body. Prostate.
Fourth month. — The closure of the cartilaginous arches of the spine is complete. Osseous
points for the first sacral vertebra and pubes. Ossification of the malleus and incus.
Corpus callosum. Membranous lamina spiralis; cartilage of the Eustachian tube. Tym-
panic rinff. Fat subcutaneous cellular tissue. Tonsils. Closure of genital furrow and
formation of scrotum and prepuce.
Fifth month. — The two layers of decidua begin to coalesce. Osseous nuclei of axis and odontoid
process. Latei-al points of first sacral vertebra; median points of second. Osseous points
of lateral masses of ethmoid. Ossification of stapes and petrous bone. Ossification of germs
of teeth. Appearance of germs of permanent teeth. Organ of Corti. Eruption of hair
on head. Sudoriferous glands. Glands of Brunner. Follicles of tonsils and base of tongue.
Lymphatic glands. Commencement of limitation of uterus and vagina.
9 ( 129 )
130 GENERAL ANATOMY.
Sixth mo7ith.— Tomts of ossification for the anterior root of the transverse process of the seventh
cervical vertebra. Lateral points of second sacral vertebra ; median points oF third. I'he
sa.cro- vertebral angle forms. Osseous points of the manubrium sterni and of the os calcis.
The cerebral hemisphere covers the cerebellum. Papillai of the skin. Sebaceous glands.
The free border of the nail projects from the corium of the dermis. Peyer's patches. The
walls of the uterus thicken.
Seventh month. — Additional points of first sacral vertebra; lateral points of third; median
point of fourth. First osseous point of body of sternum. Osseous point for astragalus.
Disappearance of Meckel's cartilage. Cerebral convolutions. Insula of Reil. iSeparalion
of tubercula quadrigemina. Disappearance of pupillary membrane. The testicle passes
into the vaginal process of the peritoneum.
Eighth month. — Additional points for the second sacral vertebra ; lateral points for the fourth ;
median points for the fifth.
Ninth month. — Additional points for the third sacral vertebra ; lateral points for the fifth.
Osseous point for the middle turbinated bone ; for the body and great cornu of the hyoid ;
for tne second and third pieces of the body of the sternum ; for the lower end of the femur.
Ossification of the bony lamina spiralis and axis of the cochlea. Opening of the eyelids.
The testicles are in the scrotum.
DESCRIPTIVE AND SUIIGICAL ANATOMY.
The Skeleton.
The entire skeleton in tlie adult consists of 200 distinct bones. Tliese are —
The Spine or vertebral column (sacrum and coccyx included) 26
Cranium .......... 8
Face . . . . .
Os hyoides, sternum, and ribs
Upper extremities
Lower extremities
14
26
64
62
200
In tbis enumeration, tbe patellae are included as separate bones, but the
smaller sesamoid bones, and tbe ossicula auditus, are not reckoned. The teeth
l)elong to the tegumentary system.
These bones are divisible into four classes: Long^ Shorty Flcit^ and Irregidar.
The Long Bones are found in the limbs, where -they form a system of levers,
which have to sustain the weight of the trunk, and to confer the power of
locomotion. A long bone consists of a lengthened cylinder or shaft, and two
extremities. The shaft is a hollow cylinder, the walls consisting of dense com-
pact tissue of great thickness in the middle, and becoming thinner towards the
extremities; the spongy tissue is scanty, and the bone is hollowed out in its
interior to form the medullary canal. The extremities are generally somewhat
expanded for greater convenience of mutual connection, for the purposes of
articulation, and to afford a broad surface for muscular attachment. Here the
bone is made up of spongy tissue with only a thin coating of compact sub-
stance. The long bones are, the lium,erus^ radius^ idna^ feomir^ tibia, fihida,
metacarpal and metatarsal bones, and the phalanges. The clavicle is also usually
reckoned as a long bone.
Short Bones. Where a part of the skeleton is intended for strength and
compactness, and its motion is at the same time slight and limited, it is divided
into a number of small pieces united together by ligaments, and the separate
bones are short and compressed, such as the bones of the carjnis and tarsus.
These bones, in their structure, are spongy throughout, excepting at their sur-
face, where there is a thin crust of compact substance.
Flat Bones. Where the principal requirement is either extensive protection,
or the provision of broad surfaces for muscular attachment, we find the osseous
structure expanded into broad flat plates, as is seen in the bones of the skull
and the shoulder-blade. These bones are composed of two thin layers of com-
pact tissue, inclosing between them a variable quantity of cancellous tissue.
In the cranial bones, these layers of compact tissue are familiarly known as the
tables of the skull; the outer one is thick and tough; the inner one thinner,
denser, and more brittle, and hence termed the vitreous table. The intervening
cancellous tissue is called the diploe. The flat bones are, the occipital, parietal,
(131)
132 THE SKELETON.
frontal^ nasal, lachrymal, vomer, scajncUv, ossa in7iominata, slernum, ril)S, and
patella.
Tbe Irregular or Mixed bones are sucli as, from their peculiar form, cannot
be grouped under either of tlie preceding heads. Tlieir structure is similar to
that of other bones, consisting of a layer of compact tissue externally, and of
spongy cancellous tissue within. The irregular bones are, the vertehrse, sacrum,
coccyx, temporal, splienoid, ethmoid, malar, swperior maxillary, inferior maxillary,
palate, inferior turbinated, and hyoid.
Surfaces of Bones. If the surface of any bone is examined, certain eminences
and depressions are seen, to which descriptive anatomists have given the fol-
lowing names.
A prominent process projecting from the surface of a bone, which it has
never been separate from, or movable upon, is termed an apophysis (from anoq-vcaq,
an excresceiice); but if such process is developed as a separate piece from the
rest of the bone, to which it is afterwards joined, it is termed an epipihysis (from
erti^vaii, an accretion).
These eminences and depressions are of two kinds: articular, and non-articular.
Well-marked examples of articular eminences are found in the heads of the
humerus and femur; aiid of articular depressions, in the glenoid cavity of the
scapula, and the acetabulum. Non-articular eminences are designated according
to their form. Thus, a broad, rough, uneven elevation is called a tuberosity;
a small rough prominence, a tubercle; a sharp, slender, pointed eminence, a spine;
a narrow rough elevation, running some way along the surface, a ridge, or line.
The non-articular depressions are also of very variable form, and are described
as fossse, grooves, furrows, fissures, notches, etc. These non-articular eminences
and depressions serve to increase the extent of surface for the attachment of
ligaments and muscles, and are usually well marked in proportion to the mus-
cularity of the subject.
THE SPINE.
The Spine is a flexuous and flexible column, formed of a series of bones called
Yertebrse.
The Vertebra} are thirty-three in number, exclusive of those which form the
skull, and have received the names cervical, dorsal, lumbar, sacral, and coccygeal,
according to the position which they occupy; seven being found in the cervical
region, twelve in the dorsal, five in the lumbar, five in the sacral, and four in
the coccygeal.
This number is sometimes increased by an additional vertebra in one region,
or the number may be diminished in one region, the deficiency being supplied
by an additional vertebra in another. These observations do not ap])ly to the
cervical portion of the spine, the number of bones forming which is seldom
increased or diminished.
The Vertebrae in the upper three regions of the s]nnc'are separate throughout
the whole of life; but those found in the sacral and coccygeal regions are, in
the adult, firmly united, so as to form two bones — five entering into the forma-
tion of the upper bone or sacrum, and four into the terminal bone of the spine,
or coccyx.
General Characters of a Vertei5ra.
Eacli vertebra consists of two essential i^arts, an interior solid segment or
body, and a posterior segment or arcli. The arch is forme.d of two pedicles,
and two lamina;, supporting seven processes; viz., four articular, two transverse,
and one s))inous process.
The bodies of the vcrtcl)ra3 arc piled one upon tlie other, forming a strong
pillar, for the support of the cranium and trunk ; the arches forming a hollow
CERVICAL VERTEBRiE. 133
cylinder behind for tlie protection of tlie spinal cord. The different vertebrae
are connected together by means of the articular processes, and the inter-
vertebral cartilages ; while the transverse and spinous processes serve as levers
for the attachment of muscles which move the different parts of the spine.
Lastly, between each pair of vertebrte apertures exist through which the spinal
nerves pass from the cord. Each of these constituent parts must now be sepa-
rately examined.
The Body is the largest and most solid part of a vertebra. Above and below,
it is slightly concave, presenting a rim around its circumference ; and its upper
and lower surfaces are rough, for the attachment of the intervertebral fibro-
cartilages. In front, it is convex from side to side, concave from above down-
wards. Behind, it is flat from above downwards and slightly concave from side
to side. Its anterior surface is perforated by a few small apertures, for the
passage of nutrient vessels ; whilst, on the posterior surface, is a single large
irregular aperture, or occasionally more than one, for the exit of veins from the
body of the vertebra, the vense basis vertehrse.
The Pedicles project backwards, one on each side, from the upper part of the
body of the vertebra, at the line of junction of its posterior and lateral surfaces.
The concavities above and below the pedicles are the intervertehral notches ; they'
are four in number, two on each side, the inferior ones being generally the
deeper. When the vertebrae are articulated, the notches of each contiguous
pair of bones form the intervertebral foramina which communicate with the
spinal canal and transmit the spinal nerves.
The Laoninse are two broad plates of bone which complete the vertebral arch
behind, inclosing a foramen which serves for the protection of the spinal cord ;
they are connected to the body by means of the pedicles. Their upper and
lower borders are rough, for the attachment of the ligamenta sxCoflava.
The Articular Processes^ four in number, two on each side, spring from the
junction of the pedicles with the laminse. The two superior project upwards,
their articular surfaces being directed more or less backwards ; the two inferior
project downwards, their articular surfaces looking more or less forwards.^
The Sjyinous P?'oces-s projects backwards from the junction of the two laminee,
and serves for the attachment of muscles.
The Transverse Processes, two in number, project one at each side from the
point where the articular processes join the pedicle. They also serve for the
attachment of muscles.
Charactees of the Cervical VERTEBEaE (Fig. 94).
The Body is smaller than in any other region of the spine, and broader from
side to side than from before backwards. The anterior and posterior surfaces
are flattened and of equal depth ; the former is placed on a lower level than the
latter, and its inferior border is prolonged downwards so as to overlap the upper
and fore part of the vertebra below. Its upper surface is concave transversely,
and presents a projecting lip on each side ; its lower surface being convex from
side to side, concave from before backwards, and presenting laterally a shallow
concavity, which receives the corresponding projecting lip of the adjacent
vertebra. The 2J&dicles are directed obliquely outwards, and the superior inter-
vertebral notches are deeper, but narrower, than the inferior." The laminse are
narrow, long, thinner above than below, and overlap each other ; inclosing the
spinal foramen, which is very large, and of a triangular form. The spinous
processes are short and bifid at the extremity, to afford greater extent of surface
for the attachment of muscles, the two divisions being often of unequal size.
' It may, perhaps, be as well to remind the reader, that the direction of a surface is determined
by that of a line drawn at right angles to it.
134
THE SKELETON.
Tlaey increase in length from tlie fourth to the seventh. The transverse processes
are short, directed downwards, outwards, and forwards, bifid at their extremity,
and marked by a groove along their upper surface, which runs downwards and
outwards from the superior intervertebral notch, and serves for the transmission
Fiff. 94. — A Cervical Vertebra.
Anterior TalcTch of TransTroc
]! or amen f<rr Vcriehrcd A
rostericrTuhrch of Trans. Free
■ansversc Proceas.
^upuriaT Artlcalar Process
-Infe riorArticula r £roccss
of one of the cervical nerves. The transverse processes are pierced at their
base by a foramen, for the transmission of the vertebral artery, vein, and
plexus of ne-rves. Each process is formed by two roots ; the anterior root arises
from the side of the body, and corresponds to the ribs : the posterior root
springs from the junction of the pedicle with the lamina, and corresponds with
the transverse processes in the dorsal region. It is by the junction of the two
that the foramen for the vertebral vessels is formed. The extremities of each
of these roots form the anterior and posterior tubercles of the transverse processes.
The articular processes are oblique : the superior are of an oval form, flattened
and directed upwards and backwards ; the inferior downwards and forwards.
The peculiar vertebras in the cervical region are the first or Atlas ; the second
or Axis ; and the seventh or Vertebra prominens. The great modifications in
the form of the atlas and axis are designed to admit of the nodding and rotatory
movements of the head.
The Atlas (Fig. 95) (so named from supporting the globe of the head). The
chief peculiarities of this bone are, that it has neither body nor spinous process.
Fip^. 95. — 1st Cervical Vertebra, or Atlas.
Tiiherclfi :a$j^ "^.x
Trans. Prooc
To ram en for
Vcrrtehral Arf,?.
Qraoi'e fcr V^/T'^/: Art ^
and' 1?'' Gcrv.Nc-rva
Rudimentary Spin. Proc.
The body is detached from Ihc rest of ihe bono, and forms the odontoid process
of the second vertebra ; wliile the parts corresponding to the pedicles pass in
front, and join tc; form the anterior arch. The atlas consists of an anterior arch,
CERVICAL VERTEBRA . 135
a posterior arcli, and two lateral masses. The anterior arcli forms about one-
liftli of tlie bone ; its anterior surface is convex, and presents about its centre a
tubercle, for the attacliment of the Longus colli muscle ; posteriorly it is concave,
and marked by a smooth, oval or circular facet, for articulation with the odontoid
process of the axis. The posterior arch forms about two-fifths of the circumfe-
rence of the bone ; it terminates behind in a tubercle, which is the rudiment of
a spinous process, and gives origin to the Rectus capitis posticus minor. The
diminutive size of this process prevents any interference in the movements
between it and the cranium. The posterior part of the arch presents, above, a
rounded edge ; whilst, in front, immediately behind each superior articular pro-
cess, is a grove, sometimes converted into a foramen by a delicate bony spiculum
which arches backwards from the posterior extremity of the superior articular
process. These grooves represent the superior intervertebral notches, and are
peculiar from being situated behind the articular processes, instead of before
them, as in the other vertebrse. They serve for the transmission of the verte-
bral artery, which, ascending through the foramen in the transverse process,
winds round the lateral mass in a direction backwards and inwards. They
also transmit the sub-occipital nerves. On the under surface of the posterior
arch, in the same situation, are two other grooves, placed behind the lateral
masses, and representing the inferior intervertebral notches of other vertebrae.
They are much less marked than the superior. The lateral masses are the most
bulky and solid parts of the atlas, in order to support the weight of the head ;
they present two articulating processes above, and two below. The two superior
are of large size, oval, concave, and approach towards one another in front, but
diverge behind ; they are directed upwards, inwards, and a little backwards,
forming a kind of cup for the condyles of the occipital bone, and are admirably
adapted to the nodding movements of the head. Not unfrequently they are
partially subdivided by a more or less deep indentation which encroaches upon
each lateral margin. The inferior articular processes are circular in form, flat-
tened or slightly concave, and directed downwards, inwards, and a little back-
wards, articulating with the axis, and permitting the rotatory movements. Just
below the inner margin of each superior articular surface is a small tubercle, for
the attachment of a ligament which, stretching across the ring of the atlas,
divides it into two unequal parts ; the anterior or smaller segment receiving the
odontoid process of the axis, the posterior allowing the transmission of the
spinal cord and its membranes. This part of the spinal canal is of considerable
size, to afford space for the spinal cord ; and hence lateral displacement of the
atlas may occur without compression of the spinal cord. The transverse pro-
cesses are of large size, for the attachment of special muscles which assist in
rotating the head — long, not bifid, perforated at their base by a canal for the
vertebral artery, which is directed from below, upwards and backwards.
The Axis (Fig. 96) (so named from forming the pivot upon which the head
rotates). The most distinctive character of this bone is the strong prominent
process, tooth-like inform (hence the name odontoid), which rises perpendicularly
from the upper part of the body. The body is of a triangular form ; deeper in
front than behind, and prolonged downwards anteriorly so as to overlap the
upper and fore part of the adjacent vertebra. It presents in front a median
longitudinal ridge, separating two lateral depressions for the attachment of the
Longus colli muscles of each side. The odontoid process presents two articu-
lating surfaces; one in front of an oval form, for articulation with the atlas;
another behind, for the transverse ligament; the latter frequently encroaching
on the sides of the process; the apex is pointed. Below the apex the process is
somewhat enlarged, and presents on either side a rough impression for the
attachment of the odontoid or check ligaments, which connect it to the occipital
bone ; the base of the process, where it is attached to the body, is constricted, so
as to prevent displacement from the transverse ligament, which binds it in this
situation to the anterior arch of the atlas. Sometimes, however, this process
136
THE SKELETON.
does become displaced, especially in cliildren, in whom the ligaments are more
relaxed : instant death is the result of this accident. The pedicles are broad and
strong, especially their anterior extremities, which coalesce with the sides of the
body and the root of the odontoid process. The laminae are thick and strong,
Fig. 96. — 2d Cervical Vertebra, or Axis.
Odontoid Pros ,
Uovgl Surf.fui- C/?eeA Luj^
Artie. Swrf./er Trajis Li^* ■
So/n. Froe, J
Artie. Surf.foTAtlas
Trans Proe
Infer. A rtic.Proe.
Body
and the spinal foramen very large. The superior articular surfaces are round,
slightly convex, directed upwards and outwards, and are peculiar in being sup-
ported on the body, pedicles, and transverse processes. The inferior articular
surfaces have the same direction as those of the other cervical vertebrae. The
superior intervertebral notches are very shallow and lie behind the articular pro-
cesses; the inferior in front of them, as in the other cervical vertebras. The
transverse processes are very small, not bifid, and perforated by the vertebral
foramen, or foramen for the ver-
Fig. 97— 7th Cervical Yertelira, or Vertebra tebral artery, which is directed
T'ronnnens. obliquely upwards and outwards.
The spinous process is of large
size, very strong, deeply chan-
nelled on its under surfece, and
presents a bifid tubercular ex-
tremity for the attachment of
muscles, which serve to rotate
the head upon the spine.
Seventh Cervical (Fig. 97). The
most distinctive character of this
vertebra is the existence of a very
long and prominent spinous pro-
cess; hence the name "Vertebra
prominens." This process is
thick, nearly horizontal in direc-
tion, not bifurcated, and has at-
tached to it the ligamentum nu-
chas. The transverse process is
usually of large size, espccia]l_y
its posterior root; its upper sur-
face has usually a shallow groove
and it seldom ])resents more tlian a trace of bifurcation at its extremity. The
vertebral foramen is sometimes as large as in the other cervical vertebrie, usu-
ally sniallor, on one or both sides, and sometimes wanting. On the left side it
occasionally gives passage to the vertebral artery; more frequently the vertebral
Spinous Proce/h
DORSAL VERTEBRiE,
137
rein traverses it on botli sides; but the usual arrangement is for both artery and
vein to pass through the foramen in the transverse process of the sixth cervical.
Chaeactees of the Doesal Yeetebe^.
The bodies of the dorsal vertebrse resemble those in the cervical and lumbar
regions at the respective ends of this portion of the spine ; but in the middle
of the dorsal region their form is very characteristic, being heart-shaped, and
broader in the antero-posterior than in the lateral direction. They are thicker
behind than in front, flat above and below, convex and prominent in front, deeply
concave behind, slightly constricted in front and at the sides, and marked on
each side, near the root of the pedicle, by two demi-facets, one above, the other
below. These are covered with cartilage in the recent state ; and, when articu-
lated with the adjoining vertebrae, form oval surfaces for the reception of the
heads of the corresponding ribs. The pedicles are directed backwards, and the
inferior intervertebral notches are of large size, and deeper than in any other
region of the spine. The laminae are broad and thick, and the spinal foramen
small, and of a circular form. The articular processes are flat, nearly vertical
in direction, and project from the upper and lower part of the pedicles, the supe-
rior being directed backwards and a little outwards and upwards, the inferior
forwards and a little inwards and downwards. The transverse processes arise
from the same parts of the arch as the posterior roots of the transverse processes
in the neck ; they are thick, strong, and of great length, directed obliquely
backwards and outwards, presenting a clubbed extremity, which is tipped on
its anterior part by a small concave surface, for articulation with the tubercle of
a rib. Besides the articular facet for the rib two indistinct tubercles may be seen
rising from the extremity of the transverse processes, one near the upper, the
other near the lower border. In man, they are comparatively of small size, and
Fig. 98. — A Dorsal Vertebra
r.
Sitfrior Ai-tie Frocess
Di nil facet for Jicad of rdl
Facet far Tulercle of Rib
De m ijacetfor 7/ ea. d of Rlh
Ivfer. Artie .Froo
serve only for the attachment of muscles. But, in some animals, they attain
consideralDle magnitude, either for the purpose of more closely connecting the
segments of this portion of the spine, or for muscular and ligamentous attachment.
The spinous processes are long, triangular in form, directed obliquely downwards,
and terminating by a tubercular margin. They overlap one another from the
fifth to the eighth, but are less oblique in direction above and below.
138
THE SKELETON,
The peculiar dorsal vertebrae are tlie first^ ninth^ tenth, eleventh, and twelfth
(Fig. 99).
The First Dorsal Vertebra presents, on each side of the bod}^, a single entire
articular facet for the head of the first rib, and a half facet for the upper half of
the second. The upper surface of the body is like that of a cervical vertebra,
beino- broad transversely, concave, and lipped on each side. The articular sur-
faces are oblique, and the spinous processes thick, long, and almost horizontal.
Fiff. 99. — Peculiar Dorsal Vertebrae.
Ail entins facet aJjoue
A Jjewi face t h e/e u/
AlJemi-faect aSovn
— One eriiirr farei
An erd/.re faffet
^ofa C6t on Tra, ns, Pro^.
w/urM IS rtjdi.msjifa r/j
An entirtrfarrt
Nofar^tonTra vf.jiit
Infer.Artic. Pros
con vcarjndfuriicJ
outwai'd
Tlic Nintli Dorsal has no dcmi-facet beloAV. Tii Pome subjects, however, the
nintli has two demi-faccts on each side, thou the tenth has a demi-fiicet at the
nplH'i' ]iMrt; none below.
The Tenth Dorsal has (except in the cases jnst mentioned) an cnlirc arlieular
facet on each side above; it has no deini-fucet below.
LUMBAR VERTEBRA,
139
In tlie Eleventh Dorsal, the body approaclies in its form and size to tlie lum-
bar. The articular facets for the heads of the ribs, one on each side, are of large
size, and placed chiefly on the pedicles, which are thicker and stronger in this
and the next vertebra, than in any other part of the dorsal region. The trans-
verse processes are very short, tubercular at their extremities, and have no
articular facets for the tubercles of the ribs. The spinous process is short,
nearly horizontal in direction, and presents a slight tendency to bifurcation at
its extremity.
The Twelfth Dorsal has the same general characters as the eleventh ; but may
be distinguished from it by the inferior articular processes being convex and
turned outwards, like those of the lumbar vertebrae ; by the general form of the
body, laminse, and spinous process, approaching to that of the lumbar vertebrae ;
and by the transverse processes being shorter, and the tubercles at their extremi-
ties more marked.
Charactees of the Lumbar Yertebr^.
The Lumbar Yertebrae (Fig. 100) are the largest segments of the vertebral
column. The body is large, broader from side to side than from before back-
wards, about equal in depth in front and behind, flattened or slightly concave
above and below, concave behind, and deeply constricted in front and at the
Super. Artec ^ Proc
Fig. 100. — Lumbar Vertebra.
/I8r
sides, presenting prominent margins, which afford a broad basis for the support
of the superincumbent weight. The pedicles are very strong, directed back-
wards from the upper part of the bodies ; consequently the inferior intervertebral
notches are of large size. The laminae are short, but broad and strong; and the
foramen triangular, larger than in the dorsal, smaller than in the cervical region.
The superior articular processes are concave, and look almost directly inwards;
the inferior, convex, look outwards and a little forwards ; the former are sepa-
rated by a much wider interval than the latter, embracing the lower articulating
processes of the vertebra above. The transverse processes are long, slender,
directed transversely outwards in the upper three lumbar vertebrae, slanting a
little upwards in the lower two. By some anatomists they are considered
homologous with the ribs. Of the two tubercles noticed in connection with the
transverse processes in the dorsal region, the superior ones become connected
m this region with the back part of the superior. articular processes. Althou.gh
in man they are comparatively small, in some animals tliey attain considerable
size, and serve to lock the vertebree more closely together. The spinous processes
are thick and broad, somewhat quadrilateral, horizontal in .direction, thicker
below than above, and terminating by a rough uneven border.
140
THE SKELETON.
Fig. 101. — Development of a Vertebra.
f j'or eauli Laviiiut (6- u-(fJ>j
Fig. 102.
By If. Secondary Centres
r / for ench.
:i) \ Tra n a: Proo.
{ /6 ^jZi
2 gonutimtrs / j for S pi v .proo (f6yT^)
Fiff. 103.
Btf 2 add I tiara/ plates
1 for j/ppcr su rj'^ce\
of lody Lj
—ijor u7t</or surfizc^'
of body
Fig. 104.— Atlas.
Jjij 3 ceTitres
/ for ciTite?: arrA f/^-y -^ con-
, . slant.
/ for cacA ) , , ; . ,
,— T"'^ / \ ueKro bm-lli.
I Mteral. masy) •'
Fig. 105.— Axis.
Hii 0 cnitres
'^^ Zfor ndoTitoid proa f6^ mo J
^\ /for eaeh latcva i masa
' fjnr luNl ,j ( Cf^ mo.)
Fig. lOG. — I.ntnbnr Vertebra.
2 addi/ionnl cz-.Titres
'O
I s
for tuOcrcIci on .7i>/KA/ric.Pr.ic
the bodies oi' tlic lujiibai' arc luruicd
The Fifth Lumhar Vertebra is cha-
racterized by having the body mucli
thicker in front than behind, which
accords with the prominence of the
sacro-vertebral articulation, by the
smaller size of its spinous process, by
the wide interval between the inferior
articulating processes, and by the
greater size and thickness of its trans-
verse processes.
Structure of the Yertehrse. The struc-
ture of a vertebra differs in different
parts. The body is composed of light
spongy cancellous tissue, having a thin
coating of compact tissue on its ex-
ternal surface perforated by numerous
orifices, some of large size, for the
passage of vessels; its interior is tra-
versed b}^ one or two large canals for
the reception of veins, which converge
towards a single large irregular or
several small apertures at the pos-
terior part of the body of each bone.
The arch and processes projecting
from it have, on the contrary, an ex-
ceedingly thick covering of compact
tissue.
Development. Each vertebra is
formed of three primary cartilaginous
portions (Fig. 101), one for each la-
mina and its processes, and one for
the body. Ossification commences in
the laminae about the sixth week of
foetal life, in the situation where the
transverse processes afterwards pro-
ject, theossific granules shooting back-
wards to the spine, forwards to the
body, and outwards into the trans-
verse and articular processes. Ossifi-
cation in the body commences in the
middle of the cartilage about the
eighth weeic. At birth these three
pieces arc perfectly separate. During
i the first year the lamina3 become united
^ behind, by a portion of cartilage in
^ which the spinous process is ulti-
mately formed, and thus the arch is
com])icted. About the third year the
body is joined to the arch on each side,
in such a inanner that the body is
formed from the three original centres
of ossification, the amount contributed
by the pedicles increasing in extent
fi-om below upwards. Thus the bodies
of the sacral vcrtcbrfe are formed
;dmost entirely from the central nuclei,
laterally and behind by the pedicles; in
DEVELOPMENT OF THE VERTEBRA. 141
the dorsal region, tlie pedicles advance as far forwards as the articular depres-
sions for the head of the ribs, forming these cavities of reception ; and in the
neck the lateral portions of the bodies are formed entirely by the advance of
the pedicles. Before puberty, no other changes occur, excepting a gradual
increase in the growth of these primary centres, the upper and under surfaces
of the bodies, and the ends of the transverse and spinous processes, being tipped
with cartilage, in which ossific granules are not as yet deposited. At sixteen
years (Fig. 102), four secondary centres appear, one for the tip of each transverse
process, and two (sometimes united into one) for the end of the spinous process.
At twenty-one years (Fig. 103), a thin circular epiphysal plate of bone is formed
m the layer of cartilage situated on the upper and under surfaces of the body,
the former being the thicker of the two. All these become joined; and the
bone is completely formed about the thirtieth year of life.
Exceptions to this mode of development occur in the first, second, and seventh
cervical, and in the vertebrae of the lumbar region.
The Atlas (Fig. 104) is developed by two primary centres, and by one or more
epiphyses. Tiie two primary centres are destined for the two lateral or neural
masses, the ossification of which commences before birth, near the articular
processes, and extends backwards : these portions of bone are separated from one
another behind, at birth, by a narrow interval filled in with cartilage. Between
the second and third years, they unite either directly or through the medium of
an epiphysal centre, developed in the cartilage near their point of junction. The
anterior arch, at birth, is altogether cartilaginous, and this portion of the atlas
is completed by the gradual extension forwards and ultimate junction of the two
neural processes. Occasionally, a separate nucleus is developed in the anterior
arch, which, extending laterally, joins the neural processes in front of the ped-
icles ; or, there are two nuclei developed in the anterior arch, one on either side
oi the median line, which join to form a single mass, afterwards united to the
lateral portions in front of the articulating processes.
The Axis (Fig. 105) is developed by six centres. The body and arch of this
lione are formed in the same manner as the corresponding parts in the other
vertebrae: one centre for the lower part of the body, and one for each lamina.
The odontoid process consists originally of an extension upwards of the cartila-
ginous mass, in which the lower part of the body is formed. At about the sixth
month of foetal life, two osseous nuclei make their appearance in the base of this
process: they are placed laterally, and join before birth to form a conical bi-lobed
mass deeply cleft above; the interval between the cleft and the summit of the
process is formed by a wedge-shaped piece of cartilage ; the base of the process
being separated from the body by a cartilaginous interval, which gradually becomes
ossified, sometimes by a separate epiphysal nucleus. Finally, as Dr. Humphry
has demonstrated, the apex of the odontoid process has a separate nucleus.
The Seventh Cervical. The anterior or costal part of the transverse process
of the seventh cervical, is developed from a separate osseous centre at about the
sixth month of foetal life, and joins the body and posterior division of the trans-
verse process between the fifth and sixth years. Sometimes this process continues
as a separate piece, and, becoming lengthened outwards, constitutes what is
known as a cervical rib.
The Lumbar Vertehrse (Fig. 106) have two additional centres (besides those
peculiar to the vertebrae generalh^), for the tubercles, which project from the
back part of the superior articular processes. The transverse process of the first
lumbar is sometimes developed as a separate piece, which may remain perma-
nently unconnected with the remaining portion of the bone; thus forming a
lumbar rib, a peculiarity which is rarely met with.
Peogress of Ossification m the Spine Generally. Ossification of the
laminfe of the vertebrae commences at the upper part of the spine, and proceeds
gradually downwards; hence the frequent occurrence of spina bifida in the lower
part of the spinal column. Ossification of the bodies, on the other hand, com-
142
THE SKELETON.
mences a little below the centre of tlie spinal column (about tlie nintli or tentb
dorsal vertebrfce), and extends both upwards and downwards. Althouo-h how
ever, the ossific nuclei make their first appearance in the lower dorsal vertebrge
the lumbar and first sacral are those in which these nuclei are largest at birth.
Attachment of Muscles. To the Atlas are attached the Longus colli Eectus
anticus minor, Rectus lateralis, Rectus posticus minor, Obliquus superior and
inferior, Splenius colli, Levator anguli scapulae, Interspinous and Intertransverse.
To the Axis are attached the Longus colli, Obliquus inferior, Rectus posticus
major, Semi-spinalis colli, Multifidus spinae, Levator anguli scapulse, Splenius
colli, Transversalis colli. Scalenus posticus, Intertransversales, Literspinales.
To the remaining Yertebrge generally are attached, anteriorly^ the Rectus anti-
cus major, Longus colli. Scalenus anticus and posticus, Psoas magnus, Psoas
parvus, Quadratus lumborum. Diaphragm, Obliquus internus and transversalis —
posteriorly^ the Trapezius, Latissimus dorsi, Levator anguli scapulas, Rhomboideus
major and minor, Serratus posticus superior and inferior, Splenius, Sacro-lum-
balis, Longissimus dorsi, Spinalis dorsi, Cervicalis ascendens, Transversalis
colli, Trachelo-mastoid, Complexus, Semi-spinalis dorsi and colli, Multifidus
spinee, Interspinales, Supra-spinales, Intertransversales, Levatores costarum.
Sacral and Coccygeal Vertebra.
The Sacral and Coccygeal Yertebrie consist, at an early period of life, of nine
separate pieces, which are united in the adult, so as to form two bones, five
Fig. 107. — Sacrum, Anterior Surface.
j^ FTomontory
entering into llio fonnnlioii of ilio, sjicnim, four into that of the coccyx. Occa-
sionally, the cf^ccyx consists of five bones.^
' Dr. Iliiiiipliry dcHcribes tlii.s as the usual composilioii of tlie Coccyx. — On the SJceleton, p. 456.
SACRUM.
143
Fiff. 108. — Vertical Section of the Sacrum.
The Sacrum (Fig. 107) is a large triangular bone, situated at tlie lower part
of the vertebral column, and at the upper and back part of the pelvic cavity,
where it is inserted like a wedge between the two ossa innominata ; its upper
part, or base, articulating with the last lumbar vertebra, its apex with the coccyx.
The sacrum is curved upon itself, and placed very obliquely, its upper extremity
projecting forwards, and forming, with the last lumbar vertebra, a very promi-
nent angle, called the promontory^ or sacro-vertehral mvjle^ whilst its central part
is directed backwards, so as to give increased capacity to the pelvic cavity. It
presents for examination an anterior and posterior surface, two lateral surfaces,
a base, an apex, and a central canal.
The Anterior Surface is concave from above downwards, and slightly so from
side to side. In the middle are seen four transverse ridges, indicating the origi-
nal division of the bone into five separate pieces. The portions of bone inter-
vening between the ridges correspond to the bodies of the vertebrae. The body
of the first segment is of large size, and in form resembles that of a lumbar
vertebra; the succeeding ones diminish in size from above downwards, are
flattened from before backwards, and
curved so as to accommodate themselves
to the form of the sacrum, being concave
in front, convex behind. At each end
of the ridges above mentioned, are seen
the anterior sacral foramina^ analogous
to the intervertebral foramina, four in
number on each side, somewhat rounded
in form, diminishing in size from above
downwards, and directed outwards and
forwards; they transmit the anterior
branches of the sacral nerves. Exter-
nal to these foramina is the lateral mass,
consisting, at an early period of life, of
separate segments, which correspond to
the anterior transverse processes ; these
become blended, in the adult, with the
bodies, with each other, and with the
posterior transverse processes. Each
lateral mass is traversed by four broad
shallow grooves, which lodge the ante-
rior sacral nerves as they pass outwards,
the grooves being separated by prominent
ridges of bone, which give attachment
to the slips of the Pyriformis muscles.
If a vertical section is made through
the centre of the bone (Fig. 108), the
bodies are seen to be united at their cir-
cumference by bone, a wide interval
being left centrally, which, in the recent
state, is filled by intervertebral substance.
In some bones, this union is more com-
plete between the lower segments than
between the upper ones.
The Posterior Surface (Fig. 109) is convex and much narrower than the ante-
rior. In the middle line are three or four tubercles, which represent the rudi-
mentary spinous processes of the sacral vertebrae. Of these tubercles, the first
is usually prominent, and perfectly distinct from the rest ; the second and third
are either separate, or united into a tubercular ridge, which diminishes in size
from above downwards ; the fourth usually, and the fifth always, remaining
undeveloped. External to the spinous processes on each side, are the laminse,
144
THE SKELETON
broad and well marked in tlie first tliree pieces; sometimes tlie fourtli, and
fifth, being undeveloped ; in this situation the lower end of the sacral canal is
exposed. External to the lamina is a linear series of indistinct tubercles repre-
senting the articular processes ; the upper pair are large, well developed, and
correspond in shape and direction to the superior articulating processes of a lumbar
vertebra ; the second and third are small ; the fourth and fifth (iisuallj blended
together) are situated on each side of the sacral canal : they are called the
sacral cornua^ and articulate with the cornua of the coccyx. External to the
articular processes are the iowr posterior sacral foramina ; they are smaller in
size and less regular in form than the anterior, and transmit the posterior
branches of the sacral nerves. On the outer side of the posterior sacral foramina
Fioj. 109. — Sacrum, Posterior Surface.
/jjjier- X of 6^
liost.sacraZ for.
is a series of tubercles, the rudimentary posterior transverse processes of the sacral
vertebras. The first pair of transver,se tubercles are of large size, very distinct,
and correspond with each superior angle of the bone ; the second, small in size,
enter into the formation of the sacro-iliac articulation ; the third give attachment
to the oblique fasciculi of the posterior sacro-iliac ligaments ; and the fourth and-
fifth to the great sacro-sciatic ligaments. The interspace between the spinous
and transverse processes on the back of the sacrum presents a wide shallow con-
cavity, called the sacral (jroove; it is continuous above with the vertebral groove,
and lodges the origin of the Erector si'jina''.
The Lateral Surface^ broad above, becomes narrowed into a thin edge below.
Its upper half presents in front a broad ear-shaped surface for articulation with
the ilium. This is called the aniricAdar surface, and in the fresh state is coated
with cartilage. Tt is bonnded posteriorly by deep :ind uneven iniyiressions, for
tlie ;iit;i('lini(;nt of ilin posterior saei'o-iliac lig:uiients. The lower half is thni
DEVELOPMENT OF SACRUM. 145
and sliarp, and gives attacliment to the greater and lesser sacro-sciatic ligaments,
and to some fibres of the Gluteus maximus ; below, it presents a deep notch,
which is converted into a foramen by articulation with the articular process of
the upper piece of the coccyx, and transmits the anterior branch of the fifth
sacral nerve.
The Base of the sacrum, which is broad and expanded, is directed upwards
and forwards. In the middle is seen an oval articular surface, which corresponds
with the under surface of the body of the last lumbar vertebra, bounded behind
by the large triangular orifice of the sacral canal. This orifice is formed behind
l>y the spinous process and lamina of the first sacral vertebra, whilst projecting
from it on each side are the superior articular processes ; they are oval, concave,
directed backwards and inwards, like the superior articular processes of a lumbar
vertebra ; and in front of each articular process is an intervertebral notch, which
forms the lower half of the last intervertebral foramen. Lastly, on each side of
the articular surface is a broad and flat triangular surface of bone, which extends
outwards, and is continuous on each side with the iliac fossa.
The Apex^ directed downwards and forwards, presents a small oval concave
surface for articulation with the coccyx.
The Sacral Ganal runs throughout the greater part of the bone; it is large
and triangular in form above, small and flattened from before backwards below.
In this situation, its posterior wall is incomplete, from the non -development of
the laminae and spinous processes. It lodges the sacral nerves, and is perforated
by the anterior and posterior sacral foramina, through which these pass out.
Structure. It consists of much loose spongy tissue within, invested exter-
nally by a thin layer of compact tissue.
Differences in the Sacrum of the Male and Female. The sacrum in the female
is usually wider than in the male ; and it is much less curved, the upper half
of the bones being nearly straight, the lower half presenting the greatest amount
of curvature. The bone is also directed more obliquely backwards ; which
increases the size of the pelvic cavity, and forms a more prominent sacro- verte-
bral angle. In the male, the curvature is more evenly distributed over the
Avhole length of the bone, and is altogether greater than in the female.
Peculiarities of the Sacrum. This bone, in some cases, consists of six pieces;
occasionally, the number is reduced to four. Sometimes the bodies of the
first and second segments are not joined, or the laminse and spinous processes
have not coalesced. Occasionally, the upper pair of transverse tubercles are
not joined to the rest of the bone on one or both sides; and lastly, the sacral
canal may be open for nearly the lower half of the bone, in consequence of the
imperfect development of the laminae and spinous processes. The sacrum, also,
varies considerably with respect to its degree of curvature. From the exami-
nation of a large number of skeletons, it would appear, that, in one set of cases,
tlie anterior surface of this bone was nearly straight, the curvature, which was
very slight, affecting only its lower end. In another set of cases, the bone was
curved throughout its whole length, but especially towards its middle. In a
third set, the degree of curvature was less marked, and affected especially the
lower third of the bone.
Development (Fig. 110). The sacrum, formed by the union of five vertebra^,
has thirty-five centres of ossification.
The bodies of the sacral vertebrse have each three ossific centres : one for the
central part, and one for the epiphysal plates on its upper and under surface.
The arch of each sacral vertebra is developed by two centres, one for each
lamina. These unite with each other behind, and subsequently join the body.
The lateral masses have six additional centres, two for each of the first three
vertebrae. These centres make their appearance above and to the outer side of
the anterior sacral foramina (Fig. 110), and are developed into separate segments,
which correspond with the anterior transverse processes (Fig. Ill); they are sub-
10
146
THE SKELETON.
<xi lirtJi
Fiff. 111.
At 4.V
tjrxu
Fig. 110. Development of Sacrum. seqnently blended with each, otlier, and
AlZitional oentres wltli tliG bodlcs and tile posterior trans-
/or tJie firsts pieces* vorse proccsses, to form the lateral mass.
Lastly, each lateral surface of the sac-
rum is developed by two epiphysal plates
(Fig. 112); one for the auricular surface,
and one for the remaining part of ihe
thin lateral edge of the bone.
Period of Development. At about the
eighth or ninth week of foetal life,
ossification of the central part of the
bodies of the first three vertebra com-
mences ; and, at a somewhat later period,
that of the last two. Between the
sixth and eighth month ossification of
the laminse takes place; and, at about
the same period, the characteristic osse-
ous tubercles for the first three sacral
vertebra make their appearance. The
laminae join to form the arch, and
are united to the bodies, first, in the
lowest vertebrae. This occurs about the
second year, the uppermost segment ap-
pearing as a single piece about the fifth
or sixth year. About the sixteenth year
the epiphyses for the upper and under
surfaces of the bodies are formed ; and,
between the eighteenth and twentieth
years, those for each lateral surface of
the sacrum make their appearance. At
about this period the last two segments
are joined to one another ; and this pro-
cess gradually extending upwards, all
the pieces become united, and the bone
is completely formed from the twenty -
fifth to the thirtieth year of life.
Articulations. "With four bones : the
last lumbar vertebra, coccyx, and the
two ossa innominata.
Attachment of Muscles. In front, the
Pyriformis and Coccygeus, and a portion
of the Iliacus to the base of the bone ;
behind, the Grluteus maximus, Latissi-
mus dorsi, Multifidus spinie, and Erector spinas, and sometimes the Extens(jr
coccygis.
The Coccyx.
The Coccyx (xoxxvl, cuckoo)^ so called from having been compared to a cuckoo's
beak (Fig. 113), is usually formed of four small segments of bone, the most rudi-
mentary parts of the vertebral column. In each of the first three segments may
be traced a rudimentary body, articular and transverse processes; the last piece
(sometimes the third) is a mere nodule of bone, without distinct processes. All
the segments arc destitute of laminae and spinous ])roccsscs; and, consequently,
of spinal canal and intervertebral foramina. The first segment is the largest ;
it resembles the lowermost sacral vertebra, and often exists as a separate piece ;
the last three, diminishing in size from above downwards, are usually blended
together so as to form a single bone. The gradual diminution in the size of
Fig. 112.
2 Epipliysal I am nice
for each laterctl surface.
THE SPINE IN GENERAL.
147
Fig. 113— Cofcyx.
Cornva.
A n te rioT Su Tfaee
the pieces gives tliis bone a triangular form, the base of the triangle joining
the end of the sacrum. It presents for examination an anterior and posterior
surface, two borders, a base, and an apex. The an-
terior surface is slightly concave, and marked with
three transverse grooves, indicating the points of
junction of the different pieces. It has attached to it
the anterior sacro-coccygeal ligament and Levator
ani muscle, and supports the lower end of the rectum.
The posterior surface is convex, marked by transverse
grooves similar to those on the anterior surface ; and
presents on each side a lineal row of tubercles, the
rudimentary articular processes of the coccygeal ver-
tebrte. Of these, the superior pair are very large ;
and are called the cornua of the coccyx ; they project
upwards, and articulate with the cornua of- the sac-
rum, the junction between these two bones complet-
ing the fifth sacral foramen for the transmission of
the posterior branch of the fifth sacral nerve. The
lateral borders are thin, and present a series of small
eminences, which represent the transverse processes
of the coccygeal vertebras. Of these, the first on each
side is of large size, flattened from before backwards ;
and often ascends to join the lower part of the thin
lateral edge of the sacrum, thus completing the fifth
sacral foramen ; the others diminish in size from above
downwards, and are often wanting. The borders of
the coccyx are narrow, and give attachment on each
side to the sacro-sciatic ligaments and Coccygeus
muscle. The base presents an oval surface for artic-
ulation with the sacrum. The cqoex is rounded, and
has attached to it the tendon of the external Sphinc-
ter muscle. It is occasionally bifid, and sometimes
deflected to one or other side.
Development. The coccyx is developed by four centres, one for each piece.
Occasionally, one of the first three pieces of this bone is developed by two
centres, placed side by side. The ossific nuclei make their appearance in the
following order : in the first segment, at birth ; in the second piece, at from five
to ten years ; in the third, from ten to fifteen years ; in the fourth, from fifteen
to twenty years. As age advances, these various segments become united in
the following order: the first two pieces join; then the third and fourth; and,
lastly, the bone is completed by the union of the second and third. At a late
period of life, especially in females, the coccyx often becomes joined to the end
of the sacrum.
Articulation. With the sacrum.
Attachment of Muscles. On either side, the Coccygeus; behind, the Gluteus
niaximus, and Extensor coccygis, when present ; at the apex, the Sphincter ani ;
and in front, the Levator ani.
Of the Spixe in general.
The Spinal Column, formed by the junction of the vertebrae, is situated in
the median line, at the posterior part of the trunk : its average length is about
two feet two or three inches, measured along the curved anterior surface of the
column. Of this length the cervical part measures about five, the dorsal about
eleven, the lumbar about seven inches, and the sacrum and coccyx the remainder.
Yiewed in front, it presents two pyramids joined together at their bases, the
upper one being formed by all the vertebras from the second cervical to the last
148
THE SKELETON.
FiV. 114.
Jsl Cervical
or Atlas.
2:i(l Cervical
or Axis.
-Lixteral Yiew of the Spine.
/-.' Dorsal
I'/ Lum/>
,..>^
lumbar; tlie lower one by the sacrum and
coccyx. When examined more closely, the
upper pyramid is seen to be formed of three
smaller pyramids. The uppermost of these
consists of the six lower cervical vertebrge ;
its apex being formed by the axis or second
cervical; its base, by the first dorsal. The
second pyramid, which is inverted, is formed
by the four upper dorsal vertebrae, the base
being at the first dorsal, the smaller end at
the fourth. The third pyramid commences
at the fourth dorsal, and gradually increases
in size to the fifth lumbar.
Viewed laterally (Fig. 114), the spinal
column presents several curves, which cor-
respond to the different regions of the
column, and are called cervical, dorsal, lum-
bar, and pelvic. The cervical curve com-
mences at the apex of the odontoid process,
aud terminates at the middle of the second
dorsal vertebra; it is convex in front, and
is the least marked of all the curves. The
dorsal curve, which is concave forwards,
commences at the middle of the second, and
terminates at the middle of the twelfth
dorsal. Its most prominent point behind
corresponds to the body of the seventh or
eighth vertebra. The lumbar curve com-
mences at the middle of the last dorsal
vertebra, and terminates at the sacro- verte-
bral angle. It is convex anteriorly; the
convexity of the lower three vertebrse be-
ing much greater than that of the upper
ones. The jje^vzc curve commences at the
sacro-vertebral articulation, and terminates
at the point of the coccyx. It is concave
anteriorly. These curves are partly due
to the shape of the bodies of the vertebrae,
and partly to the in 1er vertebral substances,
as will be explained in the Articulations of
the Sipine.
The spine has also a slight lateral curva-
ture, the convexity of which is directed
towards the right side. This is most pro-
bably produced, as Bichat first explained,
chiefly by muscular action; most persons
using the right arm in preference to the
left, especially in making long-continued
efforts, when the body is curved to the right
side. In support of this explanation, it has
been found, by Bdclard, that in one or two
individuals who were left-handed, the lateral
curvature was directed to the left side.
The spinal column presents for examina-
lioii an anterior, a posterior, and tAVO lateral
surfaces; a base, suminit, and vcrtcbi'Jil
canal.
THE SKULL. 149
The anterior surface presents the bodies of the vertebrae separated in the recent
state bj the intervertebral disks. The bodies are broad in the cervical region,
narrow in the upper part of the dorsal, and broadest in the Inmbar region.
The whole of this surface is convex transversely, concave from above doAvn-
wards in the dorsal region, and convex in the same direction in the cervical
and lumbar regions.
The posterior surface presents in the median line spinous processes. These
are short, horizontal, with bitid extremities, in the cervical region. In the
"dorsal region, they are directed obliquely above, assume almost a vertical direc-
tion in the middle, and are horizontal below, as are also the spines of the lumbar
vertebriB. They are separated by considerable intervals in the loins, by narrower
intervals in the neck, and are closely approximated in the middle of the dorsal
region. Occasionally one of these processes deviates a little from the median
line, a fact to be remembered in practice, as irregularities of this sort are atten-
dant also on fractures or displacements of the spine. On either side of the
spinous processes, extending the whole length of the column, is the vertebral
groove formed by the laminae in the cervical and lumbar regions, where it is
shalloAV, and by the laminae and transverse processes in the dorsal region, where
it is deep and broad. In the recent state, these grooves lodge the deep muscles
of the back. External to the vertebral grooves are the articular processes, and
still more exte^rnally the transverse processes. In the dorsal region, the latter
processes stand backwards, on a plane considerably posterior to the same pro-
cesses in the cervical and lumbar regions. In the cervical region, the transverse
processes are placed in front of the articular processes, and between the inter-
vertebral foramina. In the lumbar, they are placed also in front of the articular
processes, but behind the intervertebral foramina. In the dorsal region, they
are posterior both to the articular processes and foramina.
The lateral surfaces are separated from the posterior by the articular processes
in the cervical and lumbar regions, and by the transverse processes in the dorsal.
These surfaces present in front the sides of the bodies of the vertebras, marked
in the dorsal region by the facets for articulation with the heads of the ribs.
More posteriorly are the intervertebral foramina, formed b}^- the juxtaposition of
the intervertebral notches, oval in shape, smallest in the cervical and upper part
of the dorsal regions, and gradually increasing in size to the last lumbar. They
are situated between the transverse processes in the neck, and in front of them
in the back and loins, and transmit the spinal nerves. The base of the vertebral
column is formed by the under surface of the body of the fifth lumbar vertebra ;
and the sumviit by the upper surface of the atlas. The vertebral or spinal canal
follows the different curves of the spine ; it is largest in those regions in which
the spine enjoys the greatest freedom of movement, as in the neck and loins,
where it is wide and triangular ; and narrow and rounded in the back, where
motion is more limited.
THE SKULL.
The Skull, or superior expansion of the vertebral column, is composed of four
vertebrae, the elementary parts of which are specially modified in form and size,
and almost immovably connected, for the reception of the brain, and special
organs of the senses. These vertebrae are the occipital, parietal, frontal, and
nasal. .Descriptive anatomists, however, divide the skull into two parts, the
Cranium and the Face. The Cranium (xpavoj, a helmet) is composed of eight
bones : viz., the occipital^ two parietal^ frontal^ two temporal^ sphenoid^ and ethmoid.
The Face is composed of fourteen bones : viz., the tivo nasal, tivo superior maxil-
lary, two lachrymal, two malar, two palate, two inferior turbinated, vomer, and
inferior maxillary. — The ossicula auditus, the teeth, and Wormiaii bones, are not
included in this enumeration.
150
THE SKELETON,
'Cranium^ 8 hones.
SkulL 22 hones.
Face, 1-i hones.
Occipital.
Two Parietal.
Frontal.
Two Temporal.
Splienoicl.
Etlimoid.
Two Nasal.
Two Superior Maxillary.
Two Lachrymal.
Two Malar.
Two Palate.
Two Inferior Turbinated.
Vomer.
Inferior Maxillary.
The Occipital Bone.
The Occipital Bone (Fig. 115) is situated at the back part and base of the
cranium, is trapezoid in form, curved upon itself, and presents for examination
two surfaces, four borders, and four angles.
The External Surface is convex. Midway between the summit of the bone,
and the posterior margin of the foramen magnum is a prominent tubercle, the
Fig. 115. — Occipital Bone. Outer Surface.
external occipital protuberance, for the attachment of the Ligamentura nucha3 ;
and descending from it as far as the foramen, a vertical ridge, the external
occipital crest. This tubercle and crest vary in prominence in different skulls.
There is a semicircular ridge on each side, passing outwards from the occipital
OCCIPITAL BONE. 151
protuberance. These are the superior curved Imes ; and running parallel with,
these from the middle of the crest, are the two inferior curved lines. The
surface of the bone above the superior curved lines is smooth on each side, and,
in the recent state, is,covered by the Occipito-frontalis muscle, whilst the ridges,
as well as the surfaces of the bone between them, serve for the attachment of
numerous muscles. The superior curved line gives attachment internally to
the Trapezius, above which is the aponeurosis of the occipito-frontalis, externally
to the muscular origin of the Occipito-frontalis and to the Sterno-cleido-mastoid,
to the extent shown in Fig. 115 ; the depressions between the curved lines to
the Complexus internally, the Splenius capitis and Obliquus capitis superior
externally. The inferior curved line, and the depressions below it, afford inser-
tion to the Rectus capitus posticus, major and minor.
The foramen magyniin is a large oval aperture, its long diameter extending
from before backwards. It transmits the medulla oblongata and its membranes,
the spinal accessory nerves, and the vertebral arteries. Its back part is wide
for the transmission of the cord, and the corresponding margin rough for the
attachment of the dura mater inclosing the cord ; the fore part is narrower,
being encroached upon by the condyles ; it has projecting towards it from below
the odontoid process, and its ■ margins are smooth and bevelled internally to
support the medulla oblongata. On each side of the foramen magnum are the
condyles, for articulation with the atlas : they are convex, oblong, or reniform
in shape, and directed downwards and outwards ; they converge in front, and
encroach slightly upon the anterior segment of the foramen. On the inner
border of each condj^le is a rough tubercle for the attachment of the ligaments
(check) which connect this bone with the odontoid process of the axis ; whilst
external to them is a rough tubercular prominence, the transverse or jugular
process (the representative of the transverse process of a vertebra), channelled
in front by a deep notch, which forms part of the jugular foramen, or foramen
lacerum posterius. The under surface of this process affords attachment to the
Rectus capitis lateralis ; its upper or cerebral surface presents a deep groove
which lodges part of the lateral sinus, whilst its prominent extremity is marked
by a quadrilateral rough surface, covered with cartilage in the fresh state, and
articulating with a similar surface on the petrous portion of the temporal bone.
On the outer side of each condyle, near its fore part, is a foramen, the anterior
condyloid ; it is directed downwards, outwards, and forwards, and transmits the
hypoglossal nerve, and occasionally a meningeal branch of the ascending pha-
ryngeal artery. This foramen is sometimes double. Behind each condyle is a
fossa, ^ sometimes perforated at the bottom by a foramen, the posterior condyloid,
for the transmission of a vein to the lateral sinus. In front of the foramen
magnum is a strong quadrilateral plate of bone, the basilar process, wider behind
than in front ; its under surface, which is rough, presenting in the median line
a tubercular ridge, the pharyngeal spine, for the attachment of the tendinous
raphe and Superior constrictor of the pharynx ; and, on each side of it rough
depressions for the attachment of the Recti capitis antici, major and minor.
^\iQ Internal ot: (7e?-e6?'aZ ;S'z«yace (Fig. 116) is deeply concave. The posterior
or occipital part is divided by a crucial ridge into four fossae. The two superior
fossEe receive the posterior lobes of the cerebrum, and present slight eminences
and depressions corresponding to their convolutions. The two inferior, which
receive the hemispheres of the cerebellum, are larger than the former, and com-
paratively smooth; both are marked by slight grooves for the lodgment of
arteries. At the point of meeting of the four divisions of the crucial ridge is an
eminence, the internal occipital protuberance. It nearly corresponds to that on
the outer surface, and is perforated by one or more large vascular foramina. From
' This fossa presents many variations in size. It is usually shallow: and the foramen small ;
occasionally wantinjr, on one, or Imth sides. Sometimes both fossa and foramen are large, but
coufiued to one side only ; more rarely, the fossa and foramen are very large on both sides.
i:>2
THE SKELETON.
iliis eminence, the superior division of tlie crucial ridge runs upwards to the supe-
rior angle of the bone ; it presents a deep groove for the superior longitudinal
sinus, the margins of which give attachment to the falx cerebri. The inferior
division, the internal occipital crest runs, to the posterior margin of the foramen
magnum, on the edge of which it becomes gradually lost; this ridge, which is
bifurcated below, serves for the attachment of the falx cerebri. It is usually
Fig. 116. — Occipital Bone. Inner Surface.
Hujiepi'of Allele
\'^'^f Lateral
hije riot- A nail'
marked by two small grooves, which commence on either side of the posterior
margin of the foramen magnum, join together above, and run into the depression
for the torcular Ilerophili. They lodge the occipital sinuses. The transverse
grooves pass outwards to the lateral angles ; they are deeply channelled, for the
lodgment of the lateral sinuses, their prominent margins affording attachment to
the tentorium cerebelli.^ At the point of meeting of these grooves is a depres-
sion, the torcular lierophili,^ placed a little to one or the other side of the
internal occiy)ital protuberance. More anteriorly is the I'oramcn mngnum, and
on each side of it, but nearer its anterior than its posterior part, 1he internal
openings of the anterior condyloid foramina; the internal openings of the posterior
condyloid foramina being a little external [»nd posterior to tliem, protected by a
' Usnally one of llio tranwvorso grooves is clo(M'por iviul iiroadcr tlian tlie otlior ; occasionally
both fjroovcs arc of c(iiial dcptli and brcadlli. or boUi ('(pially indistinct. Tlie broader of ihe two
transverse fjroovos is nearly always continnons with the vertical groove for the superior Ion<;'i-
tiidinal sinns, and occnpiesihe c()rresp()ndin;:( side of the median line.
2 'I'he eolnmns of blood eoniinir in different directions were supposed to bepres.seci together at
this poii:t Crorcular, a wine-press].
OCCIPITAL BONE.
153
small arcli of bone. At this part of the internal surface there is a very deej>
groove, in which the posterior condyloid foramen, when it exists, has its termi-
nation inside the skull. This groove is continuous in the complete skull with
that which separates the upper from the lower fossae, and lodges the end of the
same sinus, the lateral. In front of the foramen magnum is the basilar process,
presenting a shallow depression, the basilar groove, which slopes from behind
upwards and forwards, and supports the medulla oblongata and part of the pons
Varolii, and on each side of the basilar process is a narrow channel, which, when
united with a similar channel on the petrous portion of the temporal bone, forms
a groove, which lodges the inferior petrosal snius.
Angles. The superior angle is received into the interval between the posterior
superior angles of the two parietal bones : it corresponds with that part of the
skull in the foetus which is called the posterior fontanelle. The inferior angle is
represented by the square-shaped surface of the basilar process. At an early
period of life, a layer of cartilage separates this part of the bone from the
sphenoid; but in the adult, the union between them is osseous. The lateral
angles correspond to the outer ends of the transvers egrooves, and are received
into the interval between the posterior inferior angles of the parietal and the
mastoid portion of the temporal.
Borders. The superior extends on each side from the superior to the lateral
angle, is deeply serrated for articulation with the parietal bone, and forms, by
this union, the lambdoid suture. The inferior border extends from the lateral to
the inferior angle ; its upper half is rough, aiid articulates with the mastoid por-
tion of the temporal, forming the masto- occipital suture : the inferior half articu-
lates with the petrous portion of the temporal, forming the petro-occipital
suture ; these two portions are separated from one another by the jugular pro-
cess. In front of this process is a deep notch, which, with a similar one on the
petrous portion of the temporal, forms the foramen lacerum posterius. This
notch is occasionally subdivided into two parts by a small process of bone, and
it sometimes presents an aperture at its upper part, the internal opening of the
posterior condyloid foramen.
Structure. The occipital bone consists of two compact laminae, called the
outer and inner tahles^ having between them the diploic tissue : this bone is
especially thick at the ridges, protuberances, condyles, and anterior part of the
basilar process ; whilst at the bottom of the fossae, especially the inferior, it is
thin, semi-transparent, and destitute of diploe.
Development (Pig. 117). The occipital bone \i2lq four centres of development :
one for the posterior or occi-
Fig. 117. — Development of Occipital Bone.
Bv Four Centres.
I
i
pital part, which is formed in
membrane ; one for the basi-
lar portion, and one for each
condyloid portion, which are
formed in cartilage.
The centre for the occipi-
tal portion appears about the
tenth week of foetal life ; and
consists, according to Blandin
and Cruveilhier, of a small,
oblong plate which appears
in the situation of the occi-
pital protuberance.^ The
^condyloid portions then ossify,
and lastly the basilar portion.
At birth, the bone consists of
Si/ ^ centres
ni ii r?Ji
fjie J^- pi ere..')
sejjaraHf.
f /^
■ ocoii'i'faL
pmtioii
f J'or each eondtiioid
portion
1 for tihs^lar portion
' B^clard considers this segnient to have four centres of ossification, arranged in pairs, two
above and two below the curved lines, and Meckel describes eight, four of which correspond in
situation with those above described : of the other four, two are placed in juxtaposition, at the
upper angle of the bone, and the remaining two one at each side, in the lateral angles.
154
THE SKELETON.
four parts, separate from one another, tlie occipital portion being fissured in tlie
direction indicated in tlie plate above. At about the fourth year, the occipital
and the two condyloid pieces join; and about the sixth year, the bone consists
of a single piece. At a later period, between the eighteenth and twenty -fifth
years, the occipital and sphenoid become united, forming a single bone.
Articulations. With six bones : two parietal, two temporal, sphenoid, and
atlas.
Attachment of Muscles. To the superior curved line are attached the Occipito-
frontalis, Trapezius, and Sterno-cleido-mastoid.^ To the space between the
curved lines, the Complexus, Splenius capitis, and Obliquus superior ; to the
inferior curved line, and the space between it and the foramen magnum, the
Eectus posticus major and minor ; to the transverse process, the Rectus lateralis ;
and to the basilar process, the Rectus anticus major and minor, and Superior
Constrictor of the pharynx.
The Parietal Bones.
The Parietal Bones {paries^ a wall) form by their union the sides and roof of
the skull. Each bone is of an irregular quadrilateral form, and presents for
examination two surfaces, four borders and four angles.
Surfaces. The External surface (Fig. 118) is convex, smooth, and marked about
its centre by an eminence, called the parietal eminence, which indicates the
Fig. 118. — Left Parietal Bone. External Surface.
5 ■Afticulaiei
urvih,
]ioiii1 wliorc ossification com men cod. Crossing lhn middle of the bono in an
jtrclx'd dirodioii is a curved ridg(!, the tein])oral ridgo, lor tlic atla-eilimcnt ol llio
' To these tlie Biventer cervicis slioiild be added, ifil is regarded as a separate muscle.
PARIETAL BONE.
155
temporal fascia. Above this ridge, the surface of the bone is rough and porous,
and covered by the aponeurosis of the Occipito-frontalis ; below it the bone is
smooth, forms part of the temporal fossa, and afibrds attachment to the temporal
muscle. At the back part of the superior border, close to the sagittal suture,
is a small foramen, the parietal foramen, which transmits a vein to the superior
longitudinal sinus, and sometimes a small branch of the occipital artery. Its
existence is not constant, and its size varies considerably.
The Internal Surface (Fig. 119), concave, presents eminences and depressions
for lodging the convolutions of the cerebrum, and numerous furrows for the
ramifications of the meningeal arteries ; the latter run upwards and backwards
from the anterior inferior angle, and from the central and posterior part of the
Fiof. 119. — Left Parietal Bone. Internal Surface.
]W.l)if('r.AiujU^
iis^ (ini.Iiif€r,A:Ttal0
lower border of the bone. Along the upper margin is part of a shallow groove,
which, when joined to the opposite parietal, forms a channel for the superior
longitudinal sinus, the elevated edges of which afford attachment to the falx
cerebri. Near the groove are seen several depressions ; they lodge the Pacchio-
nian bodies. The internal opening of the parietal foramen is also seen when
that aperture exists.
Borders. The superior^ the longest and thickest, is dentated to articulate with
its fellow of the opposite side, forming the sagittal suture. The inferior is divi-
ded into three parts : of these, the anterior is thin and pointed, bevelled at the
expense of the outer surface, and overlapped by the tip of the great wing of the
sphenoid : the middle portion is arched, bevelled at the expense of the outer
surface, and overlapped by the squamous portion of the temj)oral ; the posterior
portion is thick and serrated for articulation with the mastoid portion of the
temporal. The anterior harder., deeply serrated, is bevelled at the expense of the
outer surface above, and of the inner below ; it articulates Avith the frontal bone,
156 THE SKELETON.
forming tlie coronal suture. The jjosterior border, deeply denticulated, articu-
lates with the occipital, forming the lambdoid suture.
Angles. The anterior superior^ thin and pointed, corresponds with that por-
tion of the skull which in the foetus is membranous, and is called the anterior
fontaneUe. The anterior inferior angle is thin and lengthened, being received in
the interval betw^een the great wing of the sphenoid and the frontal. This
point will be found about one inch behind the upper and outer angle of the
orbit. Its inner surface is marked by a deep groove, sometimes a canal, for the
anterior branch of the middle meningeal artery. The posterior superior angle
corresponds with the junction of the sagittal and lambdoid sutures. In the
foetus this part of the skull is membranous, and is called the posterior fontaneUe.
The posterior inferior angle articulates with the mastoid portion of the temporal
bone, and generally presents on its inner surface a broad shallow groove for
lodging part of the lateral sinus.
Development. The parietal bone is formed in membrane, being developed by
one centre, which corresponds with the parietal eminence, and makes its first
appearance about the fifth or sixth week of foetal life. Ossification gradually
extends from the centre to the circumference of the bone : the angles are con-
sequently the parts last formed, and it is in their situation, that the fontanelles
exist, previous to the completion of the growth of the bone.
Articulations. With five bones : the opposite parietal, the occipital, frontal,
temporal, and sphenoid.
Attachment of Muscles. One only, the Temporal.
The Frontal Bone.
This bone, which resembles a cockle-shell in form, consists of two portions — ■
a vertical ox frontal portion, situated at the anterior part of the cranium, form-
ing the forehead ; and a horizontal or orhito-nasal portion, which enters into the
formation of the roof of the orbits and nose.
Vertical Portion. External Surface. (Fig. 120). In the median line travers-
ing the bone from the upper to the lower part, is occasionally seen a slightly
elevated ridge, and in young subjects a suture, which represents the line of
union of the two lateral halves of which the bone consists at an early period
of life : in the adult this suture is usually obliterated, and the bone forms one
piece : traces of the obliterated suture are, however, generally perceptible at
the lower part. On either side of this ridge, a little below the centre of the
bone, is a rounded eminence, the frontal eminence. These eminences vary in
size in different individuals, and are occasionally unsymmetrical in the same
subject. They are especially prominent in cases of well-marked cerebral deve-
lopment. The whole surface of the bone above this part is smooth, and covered
by the aponeurosis of the Occipito-frontalis muscle. Below the frontal emi-
nence, and separated from it by a slight groove, is the superciliary ridge, broad
internally where it is continuous with the nasal eminence, but less distinct as it
arches outwards. These ridges are caused by the projection outwards of the
frontal sinuses,^ and give attachment to the Orbicularis palpebrarum and Corru-
gator supercilii. Beneath the superciliary ridge is the supra-orbital arch, n
curved and prominent margin, wliich forms the upper boundary of the oi-bit,
and separates the vertical from the horizontal portion of the bone. The outer
part of the arch is sharp and prominent, affording to the eye, in that situafion,
' Somo confusion is occasioned to sludonts fomnioncin"' the study of .nnatoniy, Viy tlic nanio
"sinuses" liavinfT liecn given to two perfectly different kinds of spaces connected willi tlie sknll.
It may he as well, tiierefore, to state here, at the outset, that the " sinuses" on tlie interior of the
cnininm, marked by p-rooves on the inner surface of the bones, are venous channels alonfj; wliich
ihc liUiod runs in its passage l)iick from the l)rain, while the " sinuses" on the outside of llie cranium
(ihe frontal. ethmf)idal, sphonoid. and maxilhiry) are hollow spaces in the bones themselves, M'hich
coiiimunicate with the nostrils, and contain air.
FRONTAL BONE.
157
considerable protection from injury ; the inner part is less prominent. At the
inner third of this arch is a notch, sometimes converted into a foramen bj a
bony process, and called the siipra-orhital notch or foramen. It transmits the'
supra -orbital artery, vein, and nerve. A small aperture is seen in the upper
Fig:. 120. — Frontal Bone. Outer Surface.
Ejcter/la /
Angular hroc.
Xasn/ I Sfi/ne
part of the notch, which transmits a vein from the diplcie to join the ophthalmic
vein. The supra-orbital arch terminates externally in the external angular
process, and internal angular process. The external angular process is strong,
prominent, and articulates with the malar bone ; running upwards and back-
wards from it is a sharp curved crest, the temporal ridge, for the attachment of
the temporal fascia ; and beneath it a slight concavity, that forms the anterior
part of the temporal fossa, and gives origin to the Temporal muscle. The
internal, angular processes are less marked than the external, and articulate with
the lachrymal bones. Between the internal angular processes is a rough uneven
interval, the nasal notch, which articulates in the middle line with the nasal bone,
and on either side with the nasal process of the superior maxillary bone. The
notch is continuous below with a long pointed process, the nasal spine.
Vertical Portion. Internal Surface (Fig. 121). Along the middle line is a
vertical groove, the edges of which unite below to form a ridge, the frontal
crest ; the groove lodges the superior longitudinal sinus, whilst its edges afford
attachment to the falx cerebri. The crest terminates below at a small opening,
the foramen caecum, which is generally completed behind by the ethmoid. This
foramen varies in size in different subjects, is usually partially or completely
impervious, lodges a process of the falx cerebri, and, when open, transmits a
vein from the lining membrane of the nose to the superior longitudinal sinus.
On either side of the groove, the bone is deeply concave, presenting eminences
and depressions for the convolutions of the brain, and umuerous small furrows
158
THE SKELETON.
for lodging tlie ramifications of tlie anterior meningeal arteries. Several small,
irregular fosste are also seen on either side of the groove, for the reception of
'the Pacchionian bodies.
with iSujf, 3Ljjl t , I
with Nasnl
FrontaZ Sinus
\Ejfj)(tnclcd base of Na.tal Sfitlie,
<wifh Ferj>endLedar J>lnt6 of lihiK.ood 1) J^rmm.j ^art rf B n^f <f N,?sa
Horizontal Portion. External Face. This portion of the bone consists of two
thin plates, which form the vault of the orbits, separated from one another by
the ethmoidal notch. Each orbital vault consists of a smooth, concave, trian-
gular plate of bone, marked at its anterior and external part (immediately
beneath the external angular process) by a shallow depression, the lachrymal
fossa, for lodging the lachrymal gland ; and at its anterior and internal part, by
a depression (sometimes a small tubercle) for the attachment of the fibrous
pulley of the Superior oblique muscle. The ethmoidal notch separates the two
orbital plates ; it is quadrilateral ; and filled up, when the bones are united, by
the cribriform plate of the ethmoid. The margins of this notch present several
half-cells, which, when united with corresponding half-cells on the upper surface
of the ethmoid, complete the ethmoidal cells ; two grooves are also seen crossing
these edges transversely; they are converted into canals by articulation wilh
the ethmoid, and are called the anterior and posterior ethmoidal canals; they
open on the inner wall of the orbit. The anterior one transmits the nasal nerve
and anterior ethmoidal vessels, the posterior one the posterior ethmoidal vessels.
In front of the ethmoidal notch is the nasal spine, a sharp-pointed eminence,
which projects downwards and forwards, and articulates in front with the crest
of the nasal bones ; behind, it is marked by two grooves, separated by a vertical
ridge; the ridge articulates with the perpendicular lamcllas of the ethmoid, the
grooves form part of the roof of the nasal fossre. On either side of the base
of the nasal spine are the openings of the frontal sinuses. These are two
TEMPORAL BONE.
159
irregular cavities, wliicTi extend upwards and outwards, a variable distance,
between the two tables of the skull, and are separated from one anotlier bj a
thin bony septum. They give rise to the prominences above the root of the
nose, called the nasal eminences and superciliary ridges. In the child they are
generally absent, and they become gradually developed as age advances. These
cavities vary in size in different persons, are larger in men than in women, and
are frequently of unequal size on the two sides, the left being commonly the
larger. Occasionally, the}'" are subdivided by incomplete bony laminse. They
are lined by mucous membrane, and communicate with the nose by the infundi-
bulum, and occasionally with each other by apertures in their septum.
The Interned Surface of the Horizontal Portion presents the convex upper
surfaces of the orbital plates, separated from each other in the middle line by
the ethmoidal notch, and marked by eminences and depressions for the convolu-
tions of the anterior lobes of the brain.
Borders. The border of the vertical portion is thick, strongly serrated,
bevelled at the expense of the internal table above, where it rests upon the
parietal bones, and at the expense of the external table at each side, where it
receives the lateral pressure of those bones ; this border is continued below into
a triangular rough surface, which articulates with the great wing of the sphe-
noid. The border of the horizontal portion is thin, serrated, and articulates
with the lesser wing of the sphenoid.
Structure. The vertical portion and external angular processes are very
thick, consisting of diploic tissue contained between two compact laminae. The
horizontal portion is thin, translucent,
and composed entirely of compact tissue ;
hence the facility with which instru-
ments can penetrate the cranium through
this part of the orbit.
Development (Fig. 122). The frontal
bone is formed in membrane, being de-
veloped by tivo centres, one for each
lateral half, which make their appearance,
at an early period of foetal life, in the
situation of the orbital arches. From this
point ossification extends, in a radiating
manner, upwards into the forehead, and
backwards over the orbit. At birth it
consists of two pieces, which afterwards
become united, along the middle line, by
a suture which runs from the vertex to the root of the nose. This suture
usually becomes obliterated within a few years after birth ; but it occasionally
remains throughout life.
Articulations. With twelve bones : two parietal, sphenoid, ethmoid : two nasal,
two superior maxillary, two lachrymal, and two malar.
Attachmejit of Muscles. The Corrugator supercilii, Orbicularis palpebrarum,
and Temporal, on each side.
Fig 122.— Frontal Bone at Birth.
Developed by two lateral Halves.
The Temporal Bones.
The Temporal Bones are situated at the side and at the base of the skull, and
present for examination a squamous, mastoid, and petrous portion.
The Squamous Portion (squama, a scale) (Fig. 123), the anterior and upper
part of the bone, is scale- like in form, and thin and translucent in texture. Its
outer surface is smooth, convex, and grooved at its back part for the deep tem-
poral arteries; it affords attachment to the Temporal muscle, and forms part of
the temporal fossa. At its back part may be seen a curved ridge — part of the
temporal ridge ; it serves for the attachment of the temporal fascia, limits the
160
THE SKELETON
origin of tlie Temporal muscle, and marks tlie boundary between tlie squamous and
mastoid portions of tlie bone. Projecting from the lower part of the squamous
portion is a long arched outgrowth of bone, the zygomatic process. This process is
at first directed outwards, its two surfaces looking upwards and downwards ; it
ihen appears as if twisted upon itself, and runs forwards, its surfaces now looking
inwards and outwards. The superior border of the process is long, thin, and
Fig. 123. — Left Temporal Bone. Outer Surface.
\[ustoirJ fo ram en,
sharp, and serves for the attachment of the temporal fascia. The inferior, short,
thick, and arched, has attached to it some fibres of the Masseter muscle. Its
outer surface is convex and subcutaneous; its inner is concave, and also affords
attachment to the Masseter. The extremity, broad and deeply serrated, articu-
lates with the malar bone. The zygomatic process is connected to the temporal
bone by three divisions, called its roote — an anterior, middle, and posterior. The
anterior, which is short but broad and strong, runs transversely inwards into a
rounded eminence, the eminentia articularis. This eminence forms the front
boundary of the glenoid fossa, and in the recent state is covered with cartilage.
The middle root forms the outer margin of the glenoid cavity; running obliquely
inwards, it terminates at the commencement of a well-marked fissure, the Gla-
serian fissure; whilst the posterior root, which is strongly marked, runs from the ^
u])pcr border of the zygoma, in an arched direction, upwards and backwards,
forming the posterior part of the temporal ridge. At the junction of the anterior
root with the zygoma is a projection, called the tuhercle^ for the attachment of the
external lateral ligament of the lower jaw; and between the anterior and middle
roots is an oval depression, forming part of the glenoid fossa [yrrvr,, socket), for
the reception of the condyle of the lower jaw. This fossa is bounded, in front,
by the eminentia articularis; behind, by the vaginal process; and externally,
by the auditory process and middle root of the zygoma; and is divided into two
parts by a narrow slit, the Glaserian fissure. The anterior part formed by the
squamous portion of the bone is smooth, covered in the recent slate with carti-
TEMPORAL BONE. IGl
lage, and articulates witla tlie condyle of the lower jaw. This part of the glenoid
fo3sa is separated from the auditory process by a small tubercle, the post-ylenoid
process^ the representative of a prominent tubercle which, in some of the mam-
malia, descends behind the condyle of the jaw, and prevents it being displaced back-
wards during mastication (Humphry). The posterior part of the glenoid fossa is
formed chiefly by the vaginal process of the petrous portion, and lodges part of the
parotid gland. The Glaserian fissure, which leads into the tympanum, lodges the
processes gracilis of the malleus, and transmits the Laxator tympani muscle and
the tympanic branch of the internal maxillary artery. The chorda tympani nerve
passes through a separate canal, parallel to the Glaserian fissure (canal of liuguier),
on the outer side of the Eustachian tube, in the retiring angle between the
squamous and petrous portions of the temporal bone.^
The internal surface of the squamous portion (Fig. 124) is concave, presents
numerous eminences and depressions for the convolutions of the cerebrum, and
two well-marked grooves for the branches of the middle meningeal artery.
Borders. The superior border is thin, bevelled at the expense of the internal
surface, so as to overlap the lower border of the parietal bone, forming the
squamous suture. The anterior inferior border is thick, serrated, and bevelled,
alternately at the expense of the inner and outer surfaces, for articulation with
the great wing of the sphenoid.
The Mastoid Portion (^uartroj, a nipple or teat) is situated at the posterior part
of the bone; its outer surface is rough, and perforated by numerous foramina:
one of these, of large size, situated at the posterior border of the bone, is termed
the mastoid foramen ; it transmits a vein to the lateral sinus aiid a small artery.
The position and size of this foramen are very variable. It is not always present ;
sometimes it is situated in the occipital bone, or in the suture between the temporal
and the occipital. The mastoid portion is continued below into a conical pro-
jection, the mastoid process, the size and form of which vary somcAvhat. This
process serves for the attachment of the Sterno- mastoid, Splenius capitis, and
Trachelo-mastoid muscles. On the inner side of the mastoid process is a deep
groove, the digastric fossa, for the attachment of the Digastric muscle; and,
running parallel with it, but more internal, the occipital groove, which lodges
the occipital artery. The internal surface of the mastoid portion presents a deep
curved groove, which lodges part of the lateral sinus ; and into it may be seen open-
ing the mastoid foramen. A section of the mastoid process shows it to be hollowed
out into a number of cellular spaces, communicating with each other, called the
mastoid cells; they open by a single or double orifice into the back of the tympa-
num ; are lined by a prolongation of its lining membrane ; and, probably, form
some secondary part of the organ of hearing. The mastoid cells, like the other
sinuses of the cranium, are not developed until after puberty; hence the promi-
nence of this process in the adult.
Borders. The superior border of the ma,stoid portion is broad and rough, its
serrated edge sloping outwards, for articulation with the posterior inferior angle
of the parietal bone. The posterior border, also uneven and serrated, articu- '
lates with the inferior border of the occipital bone between its lateral angle and
jugular process.
The Petrous Portion (rtlr-po?, a, stone\ so named from its extreme density and
hardness, is a pyramidal process of bone, wedged in at the base of the skull
between the sphenoid and occipital bones. Its direction from without is inwards,
forwards, and a little downwards. It presents for examination a base, an apex,
three surfaces, and three borders ; and contains, in its interior, the essential
parts of the organ of hearing. The hase is applied against the internal surface
of the squamous and mastoid portions, its upper half being concealed ; but its
lower half is exposed by the divergence of those two portions of the bone which
' This small fissnre must not be confounded with the large canal which lies above the Eustachian
tube and transmits the Tensor tvmpani muscle.
11
162
THE SKELETON.
brings into view tlie oval expanded orifice of a canal leading into tlie tympanum,
the meatus auditorius externus. This canal is situated between the mastoid
process and the posterior and middle roots of the zygoma ; its upper margin is
smooth and rounded, but the greater part of its circumference is surrounded by
a curved plate of bone, the auditory process, the free margin of which is thick
and rough, for the attachment of the cartilage of the external ear.
Fig. 124. — Left Temporal Bone. Inner Surface.
}. ,. -.1, ^.
Aqtceduetii
BcpTCSsiwii for Uara-viaier
Mcatuo Aiiditorms inier-WA.?
■£:,airu'iu£ for S'upenor Sewieirrular Ca?iaL
Hiatus FaUopiij
O^cniTujfor Smaller Petrosal N'^TVc
UcpTessLan for Cassenan gaitgho'iv
Bristle passed lAmu^/h Cai-oud C.utal
The ci'pex of the petrous portion, rough and uneven, is received into the
angular interval between the posterior border of the great wing of the sphenoid
and the basilar process of the occipital ; it presents the anterior or internal ori-
fice of the carotid canal, and forms the posterior and external boundary of the
foramen lacerum medium.
The anterior surface of the petrous portion (Fig. 124), forms the posterior part
of the middle fossa of the skull. This surface is continuous with the squamous
portion, to which it is united by the suture, the temporal suture, the remains of
which are distinct even at a late period of life ; it presents six points for exami-
nation: 1. an eminence near the centre, which indicates the situation of the
superior vertical semicircular canal : 2. on the outer side of this eminence a de-
pression, indicating the position of the tympanum, the layer of the bone which
separates the tympanum from the cranial cavity being extremely thin : 3. a
shallow groove, sometimes double, leading outAvards and baclcwards to an oblique
opening, the hiatus Fallopii, for the passage of the petrosal branch of the Vidian
nerve: 4. a smaller opening, occasionally seen external to llic latter for the
passage of the smaller petrosal nerve: 5. near the apex of the bone the termi-
nation of the carotid canal, the wall of which in this situation is deficient in
front : 6. above this canal a shallow dciircssion Cor the reception of the Casse-
rian ganglion.
Tlie 'poHlerior surface forms the front part of the ])(ist(M'ior fossa of the skull,
and is continuous with the inner surface of the mastoid portion of the bone.
TEMPORAL BONE.
163
It presents three points for examination : 1, about its centre, a large orifice, tlie
meatus auditorius internus, wliose size varies considerably ; its margins are
smooth and rounded ; and it leads into a short canal, about four lines in length,
which runs directly outwards, and is closed by a vertical plate, divided by a
Fig. 125. — Petrous Portion. Inferior Surface.
and. Teiwor rymj;ani<musc-L
^F'"'*^^ of carctul aamcd
Co'ialfyr JacoUono nerve
Aaurdiinms Cor/Jatc
Canal for Arnold's mrv,
JwjuJar fosna
^'^igmal -prucesis
^ , Styloid- process-
^ ti/lo- mastoid foTdviejt
Ji'^wlaT Surface
AuristiZaT fisiuro
STYLO -P(|«Ry^,(l£.yg
horizontal crest into two unequal portions ; the canal transmits the facial and
auditory nerves, and auditory artery, a branch of the basilar : 2. behind the
meatus auditorius, a small slit, almost hidden by a thin plate of bone, leading
to a canal, the aqugeductus vestibuli, which transmits a small artery and vein,
and lodges a process of the dura mater : 3. in the interval between these two
openings, but above them, an angular depression which lodges a j^rocess of the
dura mater, and transmits a small vein into the cancellous tissue of the bone.
The inferior or basilar surface (Fig. 125) is rough and irregular, and forms part
of the base of the skull. Passing from the apex to the base this surface pre-
sents eleven points for examination: 1. a rough surface, quadrilateral in form,
which serves partly for the attachment of the Levator palati and Tensor tympani
muscles : 2. the large circular aperture of the carotid canal, which ascends at
first vertically, and then making a bend, runs horizontally forwards and inwards ;
it transmits the internal carotid artery and the carotid plexus : 3. the aquse-
ductus cochlese, a small triangular opening, lying on the inner side of the latter,
close to the posterior border of the petrous portion ; it transmits a vein from the
cochlea, which joins the internal jugular: 4. behind these openings a dee]?
depression, the jugular fossa, which varies in depth and size in different skulls ;
it lodges the internal jugular vein, and, with a similar depression on the margin
of the occipital bone, forms the foramen lacerum posterius: 5. a small foramen
for the passage of Jacobson's nerve (the tympanic branch of the glosso-pharjm-
geal) ; this foramen is seen in front of the bony ridge dividing the carotid canal
164
THE SKELETON.
from the jugular fossa: 6. a small foramen on the inner wall of the jugular
fossa, for the entrance of the auricular branch of the pneumogastric (Arnold's)
nerve: 7. behind the jugular fossa, a smooth square-shaped facet, the jugular
surface ; it is covered with cartilage in the recent state, and articulates with
the jugular process of the occipital bone : 8. the vaginal process, a very broad
sheath-like plate of bone, which extends from the carotid canal to the mastoid
process ; it divides behind into two laminse, receiving between them the 9th
point for examination, the styloid process ; a long sharp spine, about an inch in
length, continuous with the vaginal process, between the lamina of which it is
received; it is directed downwards, forwards, and inwards, varies in size and
shape, and sometimes consists of several pieces united by cartilage ; it affords
attachment to three muscles, the Stylo-pharyngeus, Stylo-glossus, and Stylo-
hyoideus ; and two ligaments, the stylo-hyoid and stylo-maxillary : 10. the
stylo-mastoid foramen, a rather large orifice, placed between the styloid and
mastoid processes ; it is the termination of the aquseductus Fallopii, and transmits
the facial nerve and stylo-mastoid artery : 11. the articular fissure, situated
between the vaginal and mastoid processes, for the exit of the auricular branch
of the pneumogastric nerve.
Bodies of the Petrous Portion. The swperior., the longest, is grooved for the
superior petrosal sinus, and has attached to it the tentorium cerebelli ; at its
inner extremity is a semilunar notch, upon which the fifth nerve lies. The
•posterior border is intermediate in length between the superior and the anterior.
Its inner half is marked by a groove, which, when completed by its articula-
tion with the occipital, forms the channel for the inferior petrosal sinus. Its
outer half presents a deep excavation — the jugular fossa — which, with a similar
notch on the occipital, forms the foramen lacerum posterius. A projecting
eminence of bone occasionally stands out from the centre of the notch, and
divides the foramen into two parts. The anterior border is divided into two
parts — an outer joined to the squamous portion by a suture, the remains of
which are distinct ; an inner, free, articulating with the spinous process of the
sphenoid. At the angle of junctiou
Fiff. 126.
-Development of the Temporal Bone.
By Four Centres.
f#^v:
of the petrous and squamous portions
are seen two canals, separated from one
another by a thin plate of bone, the
processus cochleariformis : they both
lead into the tympanum, the upper
one transmitting the Tensor tympani
muscle, the lower one the Eustachian
tube.
Structure. The squamous portion
is like that of the other cranial bones,
the mastoid portion cellular, and the
petrous portion dense and hard.
I)evelox>mcnt (Fig. 126). The
temporal bone is developed by four
centres, exclusive of those for the in-
ternal ear and the ossicula, viz.: one
for the squamous y)ortion including the
zygoma, one for the petrous aud mas-
toid parts, one for the styloid, and one
for the auditory process (tympanic
bone). The first traces of the develop-
ment of this bone appear in the squa-
mous portion, about the time when osseous matter is deposited in the vcrtcbra3;
the auditory ])roccss succeeds next ; it consists of a curved piece of bone, form-
ing about three-fotirths of a circle, the deficiency being above ; it is grooved
along its concave surface for the attachment of the mcmbrana tympani, and
I for Sifuamous
■poTtwn include.
Zuqoina,.
ZV^ mo
I for Aiiditorii
i fnr Petrous
portLVTii
i fuv StyJciJ, KTiir.
SPHENOID BONE.
165
becomes "united by its extremities to the squamous portion during the last
months of intra-uterine life. The petrous and mastoid portions then become
ossified, and lastly the styloid process, which remains separate a considerable
period, and is occasionally never united to the rest of the bone. At birth, the
temporal bone, excluding the styloid process, is formed of three pieces — the
squamous and zygomatic, the petrous and mastoid, and the auditory. The
auditory process joins with the squamoas about the time of birth. The petrous
and mastoid join with the squamous during the first year, and the styloid pro-
"^ cess becomes united between the second and third years. The subsequent
changes in this bone are, that the auditory process extends outwards, so as to
form the meatus aditorius ; the glenoid fossa becomes deeper ; and the mastoid
part, which at an early period of life is quite flat, enlarges from the develop-
ment of the cellular cavities in its interior.
Articulations. With five bones — occipital, parietal, sphenoid, inferior maxil-
lary, and malar.
Attachments of Muscles. To the squamous portion, the Temporal ; to the
zygoma, the Masseter ; to the mastoid portion, the Occipito-frontalis, Sterno-
mastoid, Splenius capitis, Trachelo-mastoid, Digastricus, and Eetrahens aurem ;
to the styloid process, the Stylo-pharyngeus, Stylo-hyoideus, and Stjdo-glossus ;
and to the petrous portion, the Levator palati, Tensor tympani, and Stapedius.
The Sphenoid Bone.
The Sphenoid Bone (ff^-^v, a wedye) is situated at the anterior part of the base
of the .skull, articulating with all the other cranial bones, which it binds firmly
and solidly together. In its form it somewhat resembles a bat, with its wings
extended ; and is divided into a central portion or body, two greater and two
lesser wings extending outwards on each side of the body ; and two processes,
the pterygoid processes, which project from it below.
The Body is of large size, cuboid in form, and hollowed out in its interior so
as to form a mere shell of bone. It presents for examination /owr surfaces — a
superior, an inferior, an anterior, and a posterior.
Fig. 127. — Sphenoid Bone. Superior Surface.
MiMle Ckiu>ui praces. ^^j^^-^^j ^
_FusleTior CLiTivid jjrocc^i^ \ Q^^^^^pi, '
Tora-men Optvcw
Foratnon lacei-u.m
aiiuriii.s, or SjjhiwidalFis^iLre
Tontrntin JlattJiiJu.m ''
I, Vosaliv
The superior surface (Fig. 127). In front is seen a prominent spine, the
ethmoidal spine, for articulation with the ethmoid ; behind this a smooth sur-
166
THE SKELETON
face presenting, in the median line, a sliglit longitudinal eminence, with a depres-
sion on each side, for lodging the olfactory nerves. A narrow transverse groove,
the optic groove, bounds the above-mentioned surface behind ; it lodges the optic
commissure, and terminates on either side in the optic foramen, for the passage
of the optic nerve and ophthalmic artery. Behind the optic groove is a small
eminence, olive-like in shape, the olivary process; and still more posteriorly,
a deep depression, the pituitary fossa, or "sella Turcica," which lodges the
pituitary body. This fossa is perforated by numerous foramina, for the trans-
mission of nutrient vessels to the substance of the bone. It is bounded in front
by two small eminences, one on either side, called the middle clinoid processes
(xXi'i/ij, a led), and behind by a square-shaped plate of bone, terminating at each
superior angle in a tubercle, the posterior clinoid processes, the size and form
of which vary considerably in diiferent individuals. These processes deepen
the pituitary fossa ; and serve for the attachment of prolongations from the
tentorium cerebelli. The sides of the plate of bone supporting the posterior
clinoid processes are notched for the passage of the sixth pair of nerves; and
behind, this plate of bone presents a shallow depression, which slopes obliquely
backwards, and is continuous with the basilar groove of the occipital bone; it
supports the upper part of the pons Varolii. On either side of the body is a
broad groove, curved something like the italic letter/; it lodges the internal
carotid and the cavernous sinus, and is called the cavernous groove. The posterior
surface^ quadrilateral in form, articulates with the basilar process of the occipital
bone. During childhood these bones are separated by a layer of cartilage : but
in after-life (between the eighteenth and twenty-fifth years) this becomes ossified,
ossification commencing above, and extending downwards; and the two bones
then form one piece. The anterior surface (Fig. 128) presents, in the middle line,
Fig. 128. — Sphenoid Bone. Anterior Surface.'
^tcrifcjoliJ JSiilc/e
Ilwntu.l4j.i' firooess
a vertical lamella of bone which articulates in front with the perpendicular plate
of the ethmoid, forming part of the septum of the nose. On either side of it are
the irregular openings leading into the sphenoid cells or sinuses. These arc
two large irregular cavities, hollowed out of the interior of the body of the
sphenoid bone, and separated from one another by a more or less complete
perpendicular bony septum. Their form and size vary considerably; they are
' In lliis fi^niro, I10II1 tlm nntcrinr and inferior snrfiicos of tlio body of tlic sphenoid bone are
shown, the bone being held wilh Uk; plci'y^oid [jrocesses ahnost hurizonlul.
SPHENOID BONE. 167
seldom symmetrical, and are often partially subdivided by irregular osseous
laminae. Occasionally, tbey extend into the basilar process of the occipital
nearly as far as the foramen magnum. The septum is seldom quite vertical,
being commonly bent to one or the other side. These sinuses do not exist in
children, but they increase in size as age advances. They are partially closed,
in front and below, by two thin curved plates of bone, the sphenoidal turbinated
bones, leaving a round opening at their upper parts, by which they communicate
with the upper and back part of the nose, and occasionally with the posterior
ethmoidal cells or sinuses. The lateral margins of this surface present a serrated
edge, which articulates with the os planum of the ethmoid, completing the pos-
terior ethmoidal cells; the lower margin, also rough and serrated, articulates
with the orbital process of the palate bone; and the upper margin with the
orbital plate of the frontal bone. The inferior surface presents, in the middle
line, a triangular spine, the rostrum, which is continuous with the vertical plate
on the anterior surface, and is received into a deep fissure between the alge of
the vomer. On each side may be seen a projecting lamina of bone, which runs
horizontally inwards from near the base of the pterj^goid process: these plates,
termed the vaginal processes, articulate with the edges of the vomer. Close to
the root of the pterygoid process is a groove, formed into a complete canal
when articulated with the sphenoidal process of the palate bone; it is called
the pterygo-palatine canal, and transmits the ptery go- palatine vessels and
pharyngeal nerve.
The Greater Wings are two strong processes of bone, which arise froin the
sides of the body, and are curved in a direction upwards, outwards, and back-
wards; being prolonged behind into a sharp-pointed extremity, the spinous
process of the sphenoid. Bach wing presents three surfaces and a circumference.
The superior or cerebral surface (Fig. 127) forms part of the middle fossa of the
skull; it is deeply concave, and presents eminences and depressions for the
convolutions of the brain. At its anterior and internal part is seen a circular
aperture, the foramen rotundum, for the transmission of the second division of
the fifth nerve. Behind and external to this is a large oval foramen, the foramen
ovale, for the transmission of the third division of the fifth nerve, the small
meningeal artery, and the small petrosal nerve. At the inner side of the
foramen ovale, a small aperture may occasionally be seen opposite the root of
the pterygoid process; it is the foramen Vesalii, transmitting a small vein.
Lastly, in the apex of the spine of the sphenoid is a short canal, sometimes
double, the foramen spinosum ; it transmits the middle meningeal artery. The
external surface (Fig. 128) is convex, and divided by a transverse ridge, the
pterygoid ridge, into two portions. The superior or larger, convex from above
downwards, concave from before backwards, enters into the formation of the
temporal fossa, and gives attachment to part of the Temporal muscle. The
inferior portion, smaller in size and concave, enters into the formation of the
zygomatic fossa, and afibrds attachment to the External pterygoid muscle. It
presents, at its posterior part, a sharp-pointed eminence of bone, the spinous
process, to which are connected the internal lateral ligament of the lower jaw,
and the Laxator tympani muscle. The pterygoid ridge, dividing the temporal
and zygomatic portions, gives attachment to part of the External pterygoid
muscle. At its inner and anterior extremity is a triangular spine of bone,
which serves to increase the extent of origin of this muscle. The anterior or
orbital surface, smooth, and quadrilateral in form, assists in forming the outer
wall of the orbit. It is bounded above by a serrated edge, for articulation with
the frontal bone ; below, by a rounded border, which enters into the formation
of the spheno- maxillary fissure; internally, it enters into the formation of the
sphenoidal fissure; while externally it presents a serrated margin, for articulation
with the malar bone. At the upper part of the inner border is a notch for the
transmission of a branch of the ophthalmic artery ; and at its lower part a small
pointed spiiie of bone, which serves for the attachment of part of the loAver head
168
THE SKELETON.
of tlie External rectus. One or two small foramina may occasionally be seen
for the passage of branches of the deep temporal arteries; they are called the
eX:ternal orhital foramina. Gircumference of the great wing (Fig. 127): com-
mencing from behind, from the body of the sphenoid to the spine, the outer
half of this margin is serrated, for articulation with the petrous portion of the
temporal bone ; whilst the inner half forms the anterior boundary of the foramen
lacerum medium, and presents the posterior aperture of the Vidian canal. In
front of the spine the circumference of the great wing presents a serrated edge,
bevelled at the expense of the inner table below, and of the external above,
which articulates with the squamous portion of the temporal bone. At the tip
of the great wing a triangular portion is seen, bevelled at the expense of the
internal surface, for articulation with the anterior inferior angle of the parietal
bone. Internal to this is a broad serrated surface, for articulation with the
frontal bone : this surface is continuous internally with the sharp inner edge of
the orbital plate, which assists in the formation of the sphenoidal fissure.
The Lesser Wings (processes of Ingrassias) (Fig. 127) are two thin triangular
plates of bone, which arise from the upper and lateral parts of the body of the
sphenoid ; and, projecting transversely outwards, terminate in a sharp point.
The superior surface of each is smooth, flat, broader internally than externally,
and supports the anterior lobe of the brain. The inferior surface forms the
back part of the roof of the orbit, and the upper boundary of the sphenoidal
fissure or foramen lacerum anterius. This fissure is of a triangular form, and
leads from the cavity of the cranium into the orbit ; it is bounded internally by
the body of the sphenoid — ^above, by the lesser wing ; below, by the internal
margin of the orbital surface of the great wing — and is converted into a foramen
by the articulation of this bone with the frontal. It transmits the third, the
fourth, tiie ophthalmic division of the fifth and sixth nerves, and the ophthalmic
vein. The anterior border of the lesser wing is serrated for articulation with
the frontal bone ; the posterior, smooth and rounded, is received into the fissure
of Sylvius of the brain. The inner extremity of this border forms the anterior
clinoid process. The lesser wing is connected to the side of the body by two
roots, the upper thin and flat, the lower thiclcer, obliquely directed, and pre-
senting on its outer side, near its junction with the bod}^, a small tubercle, for
the attachment of the common tendon of three of the muscles of the eye.
Between the two roots is the
Fig. 129.— Sphenoid Bone. Posterior Surface. optic foramen, for the trans-
mission of the optic nerve
and ophthalmic artery.
Tlie Pterygoid processes
{rttipvi, a xoing ; fZSoj, likeness)
(Fig. 129), one on each side,
descend perpendicularly from
the point where the body and
great wing unite. Each pro-
cess consists of an external
and an internal plate, sepa-
rated behind by an inter-
vening notch, — the pterygoid
f(\^sa ; but joined partially
in front. The External
pterygoid plaie is broad and
thin, turned a httlc outwards,
and forms y.art of iho inner wall of tlic zygomatic fossa. It gives attachment,
by its outer surface, to the External pterygoid ; its inner surface forms part of
the pterygoid fossa, and gives attachment to the Internal pterygoid. The in-
ternal pterygoid plate is much narrower and longer, curving outwards, at its
extremity, into a ho(jk-like pr(jcess of bono, the luimular protjcss, around which
SPHENOID BONE. 169
turns the tendon of tlie Tensor palati muscle. At the base of this plate is a
small, oval, shallow depression, the scaphoid fossa from which arises the Tensor
palati, and above which is seen the posterior orifice of the Vidian canal. The
outer surface of this plate forms part of the pterygoid fossa, the inner surface
forming the outer boundary of the posterior aperture of the nares. The Supe-
rior constrictor of the pharynx is attached to its posterior edge. The two
pterygoid plates are separated below by an angular interval, in which the
pterygoid process, or tuberosity, of the palate bone is received. The anterior
surface of the pterygoid process is very broad at its base, and forms the poste-
rior wall of the spheno- maxillary fossa. It supports Meckel's ganglion. It
]_)resents, abovo, the anterior orifice of the Vidian canal ; and below a rough
margin, which articulates with the perpendicular plate of the palate bone.
The Sphenoidal Spongy or Turbinated Bones are two thin curved plates of bone,
which exist as separate pieces until puberty, and occasionally are not joined to
the sphenoid in the adult. They are situated at the anterior and inferior part
of the body of the sphenoid, an aperture of variable size being left in their
anterior wall, through which the sphenoidal sinuses open into the nasal fossas.
They are irregular in form, and taper to a point behind, being broader and
thinner in front. The inner surface, which looks towards the cavity of the sinus,
is concave ; their outer surface convex.
Bach bone articulates in front with the Fig 130.-Plan of the Development of
, 1 • 1 , n ■.^ J_^ i , i bpheiioicl. 13y J^our Centres,
ethmoid, externally with the palate; be- '
hind, its point is placed above the vomer, Ij^-r-eacilcssz-rv^Cn^icj^r-^ajtojlodTf
and is received between the root of the ( #«!5^^r«^^ W^/y''^^^^^^\\
pterygoid process on the outer side, and V3\^^^^^l. f ^^f^-^ /
the rostrum of the sphenoid on the inner. ^C^^» f%4r^p.^ W^"""^^
Development. The sphenoid bone is de- v^m\2!ly<^wy '
veloped by ten centres, six for the poste- \^i\ /^^J
rior sphenoidal division, and four for the \ ^ A""^' uitpurypf^M
anterior sphenoid. The six centres for ifar,a^i<}r):atuiughmi:pi')ijo-:pLuu
the posterior sphenoid are — 'One for each
greater wing and external pterygoid plate ; ijurcaJi svlwnodal turiincittd ho^
one for each internal pterygoid plate ; two
for the posterior part of the body. The four for the anterior sphenoid are, one
for each lesser wing and anterior part of the body, and one for each sphenoidal
turbinated bone. Ossification takes place in these pieces in the following order :
the greater wing and external pterygoid plate are first formed, ossific granules
being deposited close to the foramen rotundum on each side, at about the second
month of foetal life ; from thence ossification spreads outwards into the great
wing, and downwards into the external pterygoid plate. Each internal ptery-
goid plate is then formed, and becomes united to the external about the middle
of foetal life. The two centres for the posterior part of the body appear as
separate nuclei, side by side, beneath the sella Turcica; they join, about the
middle of foetal life, into a single piece, which remains ununited to the rest of
the bone until after birth. Each lesser wing is formed by a separate centre,
which appears on the outer side of the optic foramen, at about the third month ;
they become united and join with the body at about the eighth month of foetal
life. At about the end of the third year, ossification has made its appearance
in the sphenoidal spongy bones.
At birth the sphenoid consists of three pieces : viz. the greater wing and ptery-
goid processes on each side ; the lesser wings and body united. At the first
year after birth, the greater wings and body are united. From the tenth to the
twelfth year the spongy bones are partially united to the sphenoid, their junction
being complete by the twentieth 3rear. Lastly, the sphenoid joins the occipital.
Articulations. The sphenoid articulates with all the bones of the cranium, and
five of the face; the two malar, two palate, and vomer: the exact extent of ar-
ticulation with each bone is shown in the accompanying figures.
170
THE SKELETON,
Attachment of Muscles. The Temporal, External pterygoid, Internal pterygoid,
Superior constrictor. Tensor palati, Laxator tympani. Levator palpebrse, Obliquus
superior, Superior rectus. Internal rectus. Inferior rectus, External rectus.
The Ethmoid Bone.
The Ethmoid (■^d/xoi^a sieve) is an exceedingly light spongy bone, of a cubical
form, situated at the anterior part of the base of the cranium, between the two
orbits, at the root of the nose.
Fig. 131.— Ethmoid Bone. Outer Surface of Right Lateral and contributing to form each
Mass (enlarged). of these cavities. It consists
of three parts : a horizontal
plate which forms part of the
base of the cranium; a per-
pendicular plate, which forms
part of the septum nasi ; and
two lateral masses of cells.
The Horizontal or Cribri-
form Plate (Fig. 131) forms
part of the anterior fossa of
the base of the skull, and is
received into the ethmoid
notch of the frontal bone be-
tween the two orbital plates.
Projecting upwards from the
middle line of this plate, is a
thick, smooth, triangular pro-
cess of bone, the crista galli,
so called from its resemblance
to a cock's comb. Its base joins the cribriform plate. Its posterior border,
long, thin, and slightly curved, serves for the attachment of the falx cerebri.
Its anterior border, short and thick, articulates with the frontal bone, and
presents two small pro-
132. — Perpendicular Plate of Ethmoid (enlarged). Shown
by removing the Riglit Lateral Mass.
ivii/i infMarblnateJ b.
Fig,
^tJi Eihmoulai
jecting alc"e, which are
received into' corre-
sponding depressions
in the frontal, comple-
ting the foramen caecum
behind. Its sides are
smooth, and sometimes
bulging, in which case
it is found to inclose
a small sinus. On each
side of the crista galli,
the cribriform plate is
narrow, and deeply
grooved, to sup])ort the >
bulb of the olfactory
nerve, and perforated
by foramina for the
passage of its filaments.
These foramina are ar-
ranged in three rows;
the innermost, which are the largest and least numerous, are lost in grooves on
the upper part of the septum; tlie foramina of the outer row arc continued on to
the surface of the upper spongy bone. The foramina of the middle row are the
smallest ; they perforate the bone, and transmit nerves to the roof of the nose.
ETHMOID BONE
171
At tlie front part of the cribriform plate, on each side of the crista galli, is a
small fissure which transmits the nasal branch of the ophthalmic nerve; and
at its posterior part a triangular notch, which receives the ethmoidal spine of
the sphenoid.
The PerpendiGular Plate (Fig. 132) is a thin flattened lamella of bone, which
descends from the under surface of the cribriform plate, and assists in forming
the septum of the nose. It is much thinner in the middle than at the circum-
ference, and is generally deflected a little to one side. Its anterior border articu-
lates with the frontal spine and crest of the nasal bones. Its posterior, divided
into two parts, is connected by its upper half with the rostrum of the sphenoid
— by its lower half with the vomer. The inferior border serves for the attach-
ment of the triangular cartilage of the nose. On each side of the per]3endicular
plate numerous grooves and canals are seen, leading from foramina on the cribri-
form plate ; they lodge filaments of the olfactory nerves.
^h.e Lateral Masses of the ethmoid consist of a number of thin-walled cellular
cavities, the ethmoidal cells^ interposed between two vertical plates of bone, the
outer one of which forms part of the orbit, and the inner one part of the nasal
fossa of the corresponding side. In the disarticulated bone many of these cells
appear to be broken ; but when the bones are articulated, they are closed in at
every part. The upper surface of each lateral mass presents a number of appa-
rently half-broken cellular spaces; these are closed in when articulated by the
edges of the ethmoidal notch of the frontal bone. Crossing this surface are two
grooves on each side, converted into canals by articulation with the frontal;
they are the anterior and posterior ethmoidal foramina, and open on the inner
wall of the orbit. The posterior surface also presents large irregular cellular
cavities, which are closed in by articulation with the sphenoidal turbinated bones,
and orbital process of the palate. The cells at the anterior surface are completed
by the lachrymal bone and nasal process of the superior maxillary, and those
below also by the superior maxillary. The outer surface of each lateral mass is
formed of a thin smooth square plate of bone, called the os planuin; it forms part
of the inner wall of the orbit, and articulates above with the orbital plane of the
frontal ; below, with the superior maxillary and orbital process of the palate ; in
front, with the lachrymal ; and behind, with the sphenoid.
From the inferior part of each lateral mass, immediately beneath the os planum,
there projects downwards and backwards an irregular lamina of bone, called the
unciform process^ from its hook-like form; it serves to close in the upper part of
the orifice of the antrum, and articulates with the ethmoidal process of the inferior
turbinated bone. It is often broken in disarticulating the bones.
The inner surface of each lateral mass forms part of the outer wall of the
nasal fossa of the corresponding side. It is formed of a thin lamella of bone,
which descends from the under surface of the cribriform plate, and terminates
below in a free convoluted margin, the middle turbinated bone. The whole of
this surface is rough, and marked
above by numerous grooves, which run
nearly vertically downwards from the
cribriform plate : they lodge branches
of the olfactory nerve, which are dis-
tributed on the mucous membrane
covering the bone. The back part
of this surface is subdivided by a
narrow oblique fissure, the superior
meatus of the nose, bounded above
by a thin curved plate of bone — the
superior turbinated bone. By means
of an orifice at the upper part of this
fissure, the posterior ethmoidal cells
open into the nose. Below, and in
133. — Ethmoid Bone. Inner Surface of Riglit
Lateral Mass (enlarged).
172 THE SKELETON.
front of the superior meatus, is seen the convex surface of the middle turbinated
bone. It extends along the whole length of the inner surface of each lateral
mass ; its lower margin is free and thick, and its concavity, directed outwards,
assists in forming the middle meatus. It is by a large orifice at the upper and
front part of the middle meatus, that the anterior ethmoidal cells, and through
them the frontal sinuses, communicate with the nose, by means of a funnel-
shaped canal, the infundibulum. The cellular cavities of each lateral mass, thus
walled in by the os planum on the outer side, and by the other bones already
mentioned, are divided by a thin transverse bony partition into two sets, which
do not communicate with each other ; they are termed the anterior and posterior
ethinoidal cells, or sinuses. The former, more numeron.s, communicate with the
frontal sinuses above, and the middle meatus below, by means of a long flexuous
cellular canal, the infundibulum ; the posterior, less numerous, open into the
superior meatus, and communicate (occasionally) with the sphenoidal sinuses.
Development. By three centres : one for the perpendicular lamella, and one
for each lateral mass.
The lateral masses are first developed, ossific granules making their first
appearance in the os planum between the fourth and fifth months of foetal life,
and afterwards in the spongy bones. At birth, the bone consists of the two
lateral masses, which are small and ill-developed ; but when the perpendicular
and horizontal plates begin to ossify, as they do about the first year after birth,
the lateral masses become joined to the cribriform plate. The formation and
increase in the ethmoidal cells, which complete the bone, take place about the
fifth or sixth year.
Articulations. With fifteen bones: the sphenoid, two sphenoidal turbinated,^
the frontal, and eleven of the face — the two nasal, two superior maxillary, two
lachrymal, two palate, two inferior turbinated, and the vomer.
Development of the Cranium.
The development of the cranium commences at a very early period, on account of the import-
ance of the organ it is intended to protect. In its most rudimentary state, it consists of a thin
membranous capsule, inclosing the cerebrum, and accurately moulded upon its surface. This
capsule is placed external to the dura mater, and in close contact with it; its walls ai'e con-
tinuous with the canal for the spinal cord, and the chorda dorsalis, or primitive part of the
vertebral column, is continued forwards, from the spine, along the base, to its fore part, where it
terminates in a tapering point. The next step in the process of development is the formation of
cartilage. 'J'his is deposited in the base of the skull, in two symmetrical segments, one on either
side of the median line ; these subsequently coalesce, so as to inclose the chorda dorsalis — the
chief part of the cerebral capsule still retaining its membranous form. Ossification first takes
place in the roof, and is preceded by the deposition of a membranous blastema upon the surface
of the cerebral capsule, in which the ossifying process extends; the primitive membranous
capsule becoming tlie internal periosteum, and being ultimately blended with the dura mater.
' Although the bones of the vertex of the skull appear before those at the base, and make con-
siderable progress in their growth : at birth ossification is more advanced in the base, this portion
of the skull forming a solid immovable groundwork.
The I'ontanelles (Figs. 13-i, 135).
Before birth, the bones at the vertex and side of the skull are separated from each other by
membranous intervals, in which bone is deficient. Those intervals, at certain parts, are of con-
siderable size, and are termed thefonfanellea, so called from the pulsations of the brain, which
are perceptible at the anterior fontanelle, and were likened to the rising of water in a fountain.
'I'he fontanelles are four in numlier, and correspond to the junction of the four angles of the
parietal with the contiguous bones. The anterior fonlanelle is the largest, and corresporids to
the junction of the sagittal and coronal sutures ; the posterior fontanelle, of smaller size, is
fciluatod at the junction of the sagittal and laml)doid sutures ; the two remaining ones are situated
at llie inferior angles of the parietal hone. The latter are closed soon after birth ; the two at the
puperior angles remain open longer: the posterior being closed in a few months after birth ; the
anterior remaining open until the first or second year. These spaces arc gradually filled in by
' 'I'hese are not usually enumerated as separate bones of the skeleton.
CONGENITAL FISSURES AND GAPS.
173
an extension of the ossifying process, or by the development of a Wormian bone. Sometimes
the anterior fontanelle remains open beyond two years, and is occasionally persistent throughout
life.
Fig. 134 — Skull at birth, showing the An-
terior and Posterior Fontanelles.
Fig. 135.— The Lateral Fontanelles.
SUPET?XUMEEARY OR WORMIAN^ BONES.
When ossification of any of the tabular bones of the skull proves abortive, the membranous
interval which would be left is usually filled in by a supernumerary piece of bone. 'J'his is
developed from a separate centre, and gradually extends until it fills the vacant space. These
supernumerary pieces are called Wormian bones ; they are called also, from their usual form, ossa
triqaetra ; but they present much variation in situation, number, and size.
They occasionally occupy the situation of the fontanelles. Bertin, Cruvcilhier, and Cuvier
have each noticed the presence of one in the anterior fontanelle. There are two specimens in
the Museum of St. George's Hospital, which present Wormian bones in this situation. In one,
the skull of a child, the supernumerary piece is of considerable size, and of a quadrangular form.
They are occasionally found in the posterior fontanelle, appearing to replace the superior
angle of the occipital bone. Not unfrequently, there is one replacing the extremity of the great
wing of the sphenoid, or the anterior inferior angle of the parietal bone, in the fontanelle there
situated.
'I'hey have been found in the diS"erent sutures on the vertex and side of the skull, and in some
of those at the base. 'I'hey are most frequent in the lambdoid suture. Mr. Ward mentions an
instance " in which one-half of the lambdoid suture was formed by large Wormian bones disposed
in a double row, and jutting deeply into each other ; " and refers to similar specimens described
by Dumontier and Bourgery.
A deficiency in the ossification of the flat bones would appear in some cases to be symmetrical
on the two sides of the skull; for it is not uncommon to find these supernumerary bones corre-
sponding in form, size, and situation on each side. Thus, in several instances, 1 have seen a pair
of large Wormian bones symmetrically placed in the lambdoid suture; in another specimen, a
pair in the coronal suture, with a supernumerary bone in the spheno-parietal suture of both sides.
The size of these supernumerary pieces varies, they being in some cases not larger than a pin's
head, and confined to the outer table; in other cases so large, that one pair of these bones may
form the whole of the occipital bone above the superior curved lines, as described by Beclard
and Ward, 'J'heir number is generally limited to two or three ; but more than a hundred have
been found in the skull of an adult hydrocephalic skeleton. In their development, structure,
and mode of articulation, they resemble the other cranial bones.
Congenital Fissures and Gaps.
Dr. Humphry has called attention to the not unfrequent existence oi congenital fismres in the
cranial bones, the result of incomplete ossification. These fissures have been noticed in the frontal,
parietal, and squamous portion of the temporal bones ; they extend from the margin towards the
middle of the bone, and are of great interest in a medico-legal point of view, as they are liable to
be mistaken for fractures. An arrest of the ossifying process may also give rise to the deficiencies
or gaps occasionally found in the cranial bones. Such deficiencies are said to occur most fre-
quently when ossificaticn is imperfect, and to be situated near the natural apertures for vessels.
Dr. Humphry describes such deficiencies to exist in a calvarium, in the Cambridge Museum,
' Wormius, a physician in Copenhagen, is said to have given the first detailed description of
these bones.
174
THE SKELETON.
where a gap sufficiently large to admit the end of the finger is seen on either side of the sagittal
suture, in the place of the parietal foramen. There is a specimen precisely similar to this in the
Museum of St. George's Hospital; and another, in which a small circular gap exists in the
parietal bone of a young child, just above the parietal eminence. Similar deficiencies are not
unfrequentiy met with ia hydrocephalic skulls ; being most frequent, according to Dr. Humphry,
in the frontal bones ; and, in the parietal bones, on either side of the sagittal suture.
Boxes of the Face.
The Facial Bones are fourteen in number,
Two Nasal,
Two Superior Maxillary,
Two Lachrymal,
Two Malar,
viz., the
Two Palate,
Two Inferior Turbinated,
Vomer,
Inferior Maxillary.
Fig. 136.— Right Nasal Bone.
U'tt/l
d B.
nth
Fig. 137.— Left Nasal Bone.
txnth
Fro ntaZ /S'j}in.&-
cresfj
— Ojyposite' hoiw.
with
RrpeTidic'tuaT
Older Siirfaee:
nroove for uaea.1, ne rve
Imier Surface
Nasal Bones.
The Nasal are two small oblong bones, varying in size and form in different
individuals; they are placed side by side at the middle and upper part of the
face, forming, by their junction, "the bridge" of the nose. Each bone presents
for examination two sur-
faces, and four borders.
The outer surface is con-
cave from above down-
wards, convex from side
to side; it is covered by
the Pyramidalis and
Compressor nasi mus-
cles, marked by numer-
ous small arterial fur-
rows, and perforated
about its centre by a
foramen, sometimes
double, for the trans-
mission of a small vein.
Sometimes this foramen is absent on one or both sides, and occasionally the
foramen csecum opens on this surface. The inner su.rface is concave from side
to side, convex from above downwards; in which direction it is traversed by a
longitudinal groove (sometimes a canal), for the passage of a branch of the
nasal nerve. The superior border is narrow, thick, and serrated for articulation
with the nasal notch of the frontal bone. The inferior border is broad, thin,
sharp, directed obliquely downwards, outwards, and backwards, and serves for
the attachment of the lateral cartilage of the nose. This border presents about
its middle a notch, through which passes the branch of the nasal nerve above
referred to; and is prolonged at its inner extremity into a sharp spine, Avhich,
when articulated with the opposite bone, forms the nasal angle. The external
border is serrated, bevelled at the expense of the internal surface above, and
of the external below, to articulate with the nasal process of the superior maxil-
lary. The internal border, thicker above than below, articulates with its fellow
of the opposite side, and is prolonged behind into a vertical crest, which forms
part of the septum of the nose : this crest articulates with the nasal spine of the
frontal above, and the perpendicular plate of the ethmoid below.
Development. By one centre for each bone, which appears about the same
period as in the vertebr,0G.
AriirAilaiions. With, four bones: two of the craninrn, the frontal and ethmoid,
and two (;f the face, the opposite nasal and tlic superior maxillary.
No muscles arc directly attached to this bone.
SUPERIOR MAXILLARY BONE.
175
Superior Maxillary Bones.
The Superior Maxillary is one of the most important bones of the face in a
suro-ical point of view, on account of the number of diseases to which some of
its parts are liable. Its minute examination becomes, therefore, a matter of
considerable interest. It is the largest bone of the face, excepting the lower
jaw; and forms, bj its union with its fellow of the opposite side, the whole of
the upper jaw. Each bone assists in the formation of three cavities, the roof of
the mouth, the floor and outer wall of the nose, and the floor of the orbit ; and
also enters into the formation of two fossse, the zygomatic and spheno-maxillary ;
and two fissures, the spheno-maxillary and pterygo-maxillary.
The bone presents for examination a body and four processes, malar, nasal,
alveolar, and palatine.
The body is somewhat cuboid, and is hollowed out in its interior to form a
large cavity, the antrum of Highmore. Its surfaces are four — an external or
facial, a posterior or zygomatic, a superior or orbital, and an internal.
The external or facial surface (Fig. 138) is directed forwards and outwards.
In the median line of the bone, just above the incisor teeth, is a depression, the
incisive or myrtiform fossa, which gives origin to the Depressor al£e nasi. Above
and a little external to it, the Compressor nasi arises. More external, is another
Fig. 138. — Left Superior Maxillary Bone. Outer Surface.
Oilier Surface.
TCNDo ecu
Incisive fossor
PosterioT De)itul Cunuls
xiIloLini Tu.Lerosif'
'7
■S^cusjiids.
depression, the canine fossa, larger and deeper than the incisive fossa, from which
it is separated by a vertical ridge, the canine eminence, corresponding to the
socket of the canine tooth. The canine fossa gives origin to the Levator anguli
oris. Above the canine fossa is the infra-orbital foramen, the termination of
the infra-orbital canal ; it transmits the infra-orbital nerve and artery. Above
the infra-orbital foramen is the margin of the orbit, which affords partial
attachment to the Levator labii superioris proprius.
The posterior or zygomatic surface is convex, directed backwards and outwards, .
and forms part of the zygomatic fossa. It presents about its centre several
176
THE SKELETON.
apertures leading to canals in tlie substance of tlie bone ; tbey are termed tbe
IMsterior dental canals^ and transmit the posterior dental vessels and nerves. At
the lower part of this surface is a rounded eminence, the maxillary tuberosity,
especially prominent after the growth of the wisdom-tooth, rough on its inner
side for articulation with the tuberosity of the palate-bone. Immediately above
the rough surface is a groove, which, running obliquely down on the inner
surface of the bone, is converted into a canal by articulation with the palate
bone, forming the posterior palatine canal.
The swpurior or orbital surface is thin, smooth, triangular, and forms part of
the tloor of the orbit. It is bounded internally by an irregular margin which
articulates, in front, with the lachrymal; in the middle, with the os planum
of the ethmoid ; behind, with the orbital process of the palate bone ; bounded
externally by a smooth rounded edge which enters into the formation of the
spheno-maxillary fissure, and which sometimes articulates at its anterior ex-
tremity with the orbital plate of the sphenoid ; bounded, in front, by part of the
circumference of the orbit, which is continuous, on the inner side with the nasal,
on the outer side with the malar process. Along the middle line of the orbital
surface is a deep groove, the infra-orbital, for the passage of the infra-orbital
nerve and artery. This groove commences at the middle of the outer border
of the surface, and, passing forwards, terminates in a canal which subdivides
into two branches; one of the canals, the infra- orbital, opens just below the
margin of the orbit; the other, which is smaller, runs into the substance of the
anterior wall of the antrum; it is called the anterior dental canal, transmitting
the anterior dental vessels and nerves to the front teeth of the upper jaw. At
the inner and fore part of the orbital surface, just external to the lachrymal
canal, is a minute depression, which gives origin to the Inferior oblique muscle
of the eye.
The internal surface (Fig. 139) is unequally divided into two parts by a hori-
Fig. 139.— Left Superior Maxilitiry Bone. Inner Surface.
Haves' -pcftL^ny olosiv^ (?nyice cfAato-am
murkrd in ourJi/m
■Infer Lor TuTlivaf^d
zoutal projection of l)onc, the palate process; the portion above the ]^alate pro-
cess forms part of tlio outer wrdl of the nose; that below it forms part of the
SUPERIOR MAXILLARY BONE. 177
cavity of tlie moiitli. The superior division of this surface presents a large
irregular opening leading into tlie antrum of Higlimore. At the upper border
of this aperture are numerous broken cellular cavities, which, in the articulated
skull, are closed in by the ethmoid and lachrjanal bones. Below the aperture
is a smooth concavity which forms part of the inferior meatus of the nose,
traversed by a fissure, the maxillary fissure, which runs from the lower part of
the orifice of the antrum obliquely downwards and forwards, and receives the
maxillary process of the palate bone. Behind it is a rough surface which
articulates with the perpendicular plate of the palate bone, traversed by a groove,
which, commencing near the middle of the posterior border, runs obliquely
dowuAvards and forwards, and forms, when completed by its articulation with
the palate bone, the posterior palatine canal. In front of the opening of the
antrum is a deep groove, converted into a canal by the lachrymal and inferior
turbinated bones, which is coated with mucous membrane, and called the
lachrymal or nasal duct. More anteriorly is a well-marked rough ridge, the
inferior turbinated crest, for articulation with the inferior turbinated bone. The
concavity above this ridge forms part of the middle meatus of the nose ; whilst
that below it forms part of the inferior meatus. The inferior division of this
surface is concave, rough and uneven, and perforated by numerous small fora-
mina for the passage of nutrient vessels.
The Antrum of Higlimore^ or Maxillary Sinus, is a large triangular-shaped
cavity, hollowed out of the body of the maxillary bone ; its apex, directed out-
wards, is foriued by the malar process ; its base by the outer wall of the nose.
Its walls are everywhere exceedingly thin, its root being formed by the orbital
plate, its floor by the alveolar process, its anterior wall by the facial, and its
posterior by the zygomatic surface. Its inner wall, or base, presents, in the
disarticulated bone, a large irregular aperture, which communicates with the
nasal fossa. The margins of this aperture are thin and ragged, and the aperture
itself is much contracted by its articulation with the ethmoid above, the inferior
turbinated below, and the palate bone behind.^ In the articulated skull, this
cavity communicates with the middle meatus of the nose generally by two small
apertures left between the above-mentioned bones. In the recent state, usually
only one small opening exists, near the upper part of the cavity, sufficiently
large to admit the end of a probe, the other being closed by the lining mem-
brane of the sinus.
Crossing the cavity of the antrum, are often seen several projecting laminae
of bone, similar to those seen in the sinuses of the cranium ; and on its poste-
rior wall are the posterior dental canals, transmitting the posterior dental vessels
and nerves to the teeth. Projecting into the floor are several conical processes,
corresponding to the roots of the first and second molar teeth f in some cases
the floor is perforated by the teeth in this situation. It is from the extreme
thinness of the walls of this cavity, that we are enabled to explain how a
tumor growing from the antrum encroaches upon the adjacent parts, pushing
up the floor of the orbit, and displacing the eyeball, projecting inwards into the
nose, protruding forwards on to the cheek, and making its way backwards into
the zygomatic fossa, and downwards into the mouth.
The Malar Process is a rough triangular eminence, situated at the angle of
separation of the facial from the zygomatic surface. In front it is concave,
forming part of the facial surface ; behind, it is also concave, and forms part of
the zygomatic fossa ; above, it is rough and serrated for articulation with the
malar bone ; whilst below, a prominent ridge marks the division between the
' In some cases, at any rate, the lachrymal bone encroaches slig'htly on the anterior superior
portion of the opening, and assists in forming the inner wall of the antrum.
^ ^ ^ The number of teeth whose fangs are in relation with the floor of the antrum is variable.
'I'he antrum " may extend so as to be in relation to all the teeth of the true maxilla, from the
canine to the den^ sapientice." — See Mr. Salter on Abscess of the Antrum, in A System of
Surgery, edited by T. Holmes, 2d edit. vol. iv. p. 356.
12
178 THE SKELETON.
facial and zygomatic surfaces. A small part of tlie Masseter muscle arises from
this process.
The Nasal Process is a thick triangular plate of bone, wliicli projects upwards,
inwards, and backwards, by tlie side of the nose, forming part of its lateral
boundary. Its external surface is concave, smooth, perforated by numerous
foramina, and gives attachment to the Levator labii superioris alasque nasi, the
Orbicularis palpebrarum, and Tendo oculi. Its internal surface forms part of
the outer wall of the nose ; it articulates above with the frontal, and presents a
rough uneven surface, which articulates with the ethmoid bone, closing in the
anterior ethmoidal cells ; below this is a transverse ridge, the superior turbinated
crest, for articulation with the middle turbinated bone of the ethmoid, bounded
below by a smooth concavity which forms part of the middle meatus ; below this
again is the inferior turbinated crest (already described), for articulation with
the inferior tu.rbinated bone ; and still more interiorly, the concavity which forms
part of the inferior meatus. The anterior border of the nasal process is thin,
directed obliquely downwards and forwards, and presents a serrated edge for
articulation with the nasal bone : its posterior border is thick, and hollowed into
a groove for the lachrymal duct : of the two margins of this groove the inner
one articulates with the lachrymal bone, the outer one forms part of the circum-
ference of the orbit. Just where the latter joins the orbital surface is a small
tubercle, the lachrymal tubercle ; this serves as a guide to the surgeon in the
performance of- the operation for fistula lacrymalis. The lachrymal groove in
the articulated skull is converted into a canal by the lachrymal bone, and lach-
rymal process of the inferior turbinated ; it is directed downwards, and a little
backwards and outwards, is about the diameter of a goose-quill, slightly narrower
in the middle than at either extremity, and lodges the lachrymal duct.
The Alveolar Process is the thickest and most spongy part of the bone, broader
behind than in front, and excavated into deep cavities for the reception of the
teeth. These cavities are eight in number, and vary in size and depth accord-
ing to the teeth they contain. That for the canine tooth is the deepest ; those
for the molars are the widest, and subdivided into minor cavities ; those for the
incisors are single, but deep and narrow. The Buccinator muscle arises from
the outer surface of this process, as far forward as the first molar tooth.
The Palate Process^ thick and strong, projects horizontally inwards from the
inner surface of the bone. It is much thicker in front than behind, and forms a
considerable part of the floor of the nostril, and the roof of the mouth. Its
upper surface is concave from side to side, smooth, and forms part of the floor
of the nose. In front is seen the upper orifice of tlie anterior palatine (incisor)
canal, which leads into a fossa formed by the junction of the two superior max-
illary bones, and situated immediately behind the incisor teeth. It transmits
the anterior palatine vessels, the naso-palatine nerves passing through the inter-
maxillary suture. The inferior surface, also concave, is rough and uneven, and
forms part of the roof of the mouth. This surface is perforated by numero'cis
foramina for the passage of nutritious vessels, channelled at the back part of its
alveolar border by a longitudinal groove, sometimes a canal, for the transmission
of the posterior palatine vessels, and a large nerve, and presents little depres-
sions for the lodgment of the palatine glands. This surface presents anteriorly
the lower orifice of the anterior palatine fossa. In some bones a delicate linear
suture may be seen extending from the anterior palatine fossa to the interval
between tile lateral incisor and the canine tooth. This marks out the inter-
maxillary, or incisive bone, which in some animals exists permanently as a sepa-
rate piece. It includes the whole thickness of the alveolus, the corresponding
y)art of the floor of the nose, and the nasal or anterior nasal spine, and contains
the sockets of iIk^ incisor teeth. 'I'lic outer border of the palate process is in-
corporated with the rest of the bone. Tlie inner border is thicker in front than
behind, and is raised above into a ridge, which, with the corresponding ridge in
the opposite bone, forms a groove for the reception of the vomer. The anterior
LACHRYMAL BONES.
179
/ far Na na I S/
Facial. portV'
J far Oriitctl ^•
Malar jtort".^
Anterior Surf are.
at
Irtli
margin is bounded by tbe tbin concave border of tbe opening of the nose, pro-
longed forwards internally into a sliarp process, forming, with a similar process
of the opposite bone, the anterior nasal spine. The posterior border is serrated
for articulation with the horizontal plate of the palate bone.
Development. This bone is formed at such an early period, and ossification
proceeds in it with such rapidity, that it has been found impracticable hitherto
to determine with accuracy its
number of centres. It appears. Fig. 140. — Development of Superior Maxillary Bone,
however, probable that it has ^y Four Centres.
four centres of development, viz.,
one for the nasal and facial por-
tions, one for the orbital and
malar, one for the incisive, and
one for the palatal portion in-
cluding the entire palate except
the incisive segment. The inci-
sive portion is indicated in young
bones by a fissure, which marks
ofi' a small segment of the palate
including the two incisor teeth.
In some animals, this remains
permanently as a separate piece,
constituting the intermaxillary
bone ; and in the human subject,
where the jaw is malformed, as
in cleft palate, this segment may
be separated from the maxillary
bone by a deep fissure extend-
ing backwards between the two
into the palate. If the fissure
be on both sides, both segments
are quite isolated from the max-
illary bones, and hang from the end of the vomer ; they are not unfrequently
much displaced, and the deformity is often accompanied by congenital fissure of
the upper lip, either on one or both sides of the median line. The maxillary
sinus appears at an earlier period than any of the other nasal sinuses, its deve-
lopment commencing about the fourth month of foetal life.
Articulatio7is. With nine bones : two of the cranium — the frontal and eth-
moid, and seven of the face, viz., the nasal, malar, lachrymal, inferior turbinated,
palate, vomer, and its fellow of the opposite side. Sometimes it articulates with
the orbital plate of the sphenoid.
Attachment of Muscles. Orbicularis palpebrarum, Obliquus inferior oculi. Le-
vator labii superior algeque nasi, Levator labii superioris proprius. Levator anguli
oris, Compressor nasi, Depressor ala3 nasi, Masseter, Buccinator, External ptery-
goid, and Orbicularis oris.
//<.
J-^
Palatal narr^
Inferior Surf nee.
The Lachrymal Bones.
The Lachrymal are the smallest and most fragile bones of the face. They
are situated at the front part of the inner wall of the orbit, and resemble some-
what in form, thinness, and size, a finger-nail ; hence they are termed the ossa
unguis. Each bone presents, for examination, two surfaces and four borders.
The external (Fig. 141) or orbital surface is divided by a vertical ridge into two
parts. The portion of bone in front of this ridge presents a smooth, concave,
longitudinal groove, the free margin of which unites with the nasal process
of the superior maxillary bone, completing the lachrymal groove. The upper
part of this groove lodges the lachrymal sac ; the lower part assists in the for-
180
THE SKELETON.
Fig. 141. — Left Lachrymal Bone.
External Surface.
riih Frontal
mation of tlie laclirymal canal, and lodges tlie nasal duct. The portion of bone
behind the ridge is smooth, slightly concave, and forms part of the inner wall
of the orbit. The ridge with a part of the orbital
surface immediately behind it, affords attachment
to the Tensor tarsi : the ridge terminates below in
a small hook-like process, which articulates with
the lachrymal tubercle of the superior maxillary
bone and completes the upper orifice of the lach-
rymal canal. It sometimes exists as a separate
piece, which, is then called the lessor lachrymal
hone. The internal or nasal surface presents a de-
pressed furrow, corresponding to the ridge on its
outer surface. The surface of bone in front of
this forms part of the middle meatus ; and that
behind it articulates with the ethmoid bone, filling
in the anterior ethmoidal cells. Of the four
borders, the anterior is the longest, and articulates
with the nasal process of the superior maxillary
bone. The posterior, thin and uneven, articulates
with the OS planum of the ethmoid. The superior, the shortest and thickest,
articulates with the internal angular process of the frontal bone. The inferior
is divided by the lower edge of the vertical crest into two parts : the posterior
part articulates with the orbital plate of the superior maxillary bone ; the an-
terior portion is prolonged downwards into a pointed process, which articulates
with the lachrymal process of the inferior turbinated bone, and assists in the
formation of the lachrymal canal.
Development. By a single centre, which makes its appearance soon after ossi
fication of the vertebrae has commenced.
Articulations. With four bones : two of the cranium, the frontal and ethmoid,
and two of the face, the superior maxillary and the inferior turbinated.
Attachment of Muscles. The Tensor tarsi.
(SUghtLij
e alarmed j
The Malar Bones.
The Malar are two small quadrangular bones, situated at the upper and outer
part of the face : they form the prominence of the cheek, part of the outer wall
and floor of the orbit, and part of the temporal and zygomatic foss£e. Each bone
presents for examination an external and an internal surface ; four processes, the
frontal, orbital, maxillary, and zygomatic ; and four borders. The external
surface (Fig. 142) is smooth, convex, perforated near its centre by one or two
small apertures, the malar fora
Outer Surface.
Fig. 142.— Left Malar Bone.
Brim//'!! poj/acfJ throiKjh
Temporo MiUa,r (hnuLs
mina for the passage of nerves
and vessels, covered by the Or-
bicularis palpebrarum muscle,
and affords attachment' to the
Zygomaticus major and minor
muscles.
The internal surface (Fig.
143), directed backwards and
inwards, is concave, presenting
internally a rough triangular
surface, for articulation with
the superior maxillary bone;
and externally, a stiioolh eon-
cave surface, wliicli ibrins the
anterior boundary of the tem-
poral fossa above; and below,
where it is wider, forms part of
MALAR BONE.
181
Fig. 143. — Left Malar Bone. Inner Surface.
JjJl I''i-o,
tlie zygomatic fossa. Tliis sur-
face presents, a little above its
centre, tlie aperture of one or
two malar canals, and affords
attachment to part of two
muscles, the Temporal above,
and the Masseter below. Of
the four processes, the frontal
is thick and serrated, and articu-
lates with the external angular
]3rocess of the frontal bone.
The orbital process is a thick
and strong plate, which projects
backwards from the orbital
margin of the bone. Its upper
surface, smooth and concave,
forms, bj its junction with the
great ala of the sphenoid, the
outer wall of the orbit. Its
under surface, smooth and convex, forms part of the temporal fossa. Its
anterior margin is smooth and rounded, forming part of the circumference of
the orbit. Its superior margin, rough, and directed horizontally, articulates
with the frontal bone behind the external angular process. Its posterior margin
is rough and serrated for articulation with the sphenoid ; internally it is also
serrated for articulation with the orbital surface of the superior maxillary. At
the angle of junction of the sphenoidal and maxillary portions, a short rounded
non-articular margin is generally seen ; this forms the anterior boundary of the
spheno-maxillary fissure ; occasionally, no such non-articular margin exists, the
fissure being completed by the direct junction of the maxillary and sphenoid
bones, or by the interposition of a small Wormian bone in the angular interval
between them. On the upper surface of the orbital process are seen the orifices
of one or two temporo-malar canals ; one of these usually opens on the poste-
rior surface, the other (occasionally two) on the facial surface : they transmit
filaments (temporo-malar) of the orbital branch of the superior maxillary nerve.
The maxillary process is a rough triangular surface, which articulates with the
superior maxillary bone. The zygomatic process, long, narrow, and serrated,
articulates with the zygomatic process of the tem.poral bone. Of the four
borders^ the superior or orbital is smooth, arched, and forms a considerable part
of the circumference of the orbit. The inferior, or zygomatic is continuous
with the lower border of the zygomatic arch, affording attachment by its rough
edge to the Masseter muscle. The anterior or maxillary border is rough, and
bevelled at the expense of its inner table, to articulate with the superior max-
illary bone ; affording attachment by its outer margin to the Levator labii supe-
rioris proprius, just at its point of junction with the superior maxillary. The
posterior or temporal border, curved like an italic/, is continuous above with
the commencement of the temporal ridge ; below, with the upper border of the
zygomatic arch : it affords attachment to the temporal fascia.
Development. By a single centre of ossification, which appears at about the
same period when ossification of the vertebrse commences.
Articulations. With four bones : three of the cranium, frontal, sphenoid, and
temporal ; and one of the face, the superior maxillary.
Attachment, of Muscles. Levator labii superioris proprius, Zygomaticus major,
Zygomaticus minor, Masseter, and Temporal.
182
THE SKELETON.
■ The Palate Bones.
The Palate Bones are situated at the back part of the nasal foss^ ; they are
wedged in between the superior maxillary and the pterygoid process of the
sphenoid. Each bone assists in the formation of three cavities : the floor and
outer wall of the nose, the roof of the mouth, and the floor of the orbit ; and
enters into the formation of three fossge ; the zygomatic, spheno-maxillary, and
pterygoid ; and one fissure, the spheno-maxillary. In form the palate bone
somewhat resembles the letter L, and may be divided into an inferior or hori-
zontal plate, and a superior or vertical plate.
The Inferior or Horizontal Plate is thick, of a quadrilateral form, and presents
two surfaces and four borders. The superior surface, concave from side to side,
forms the back part of the floor of the nostril. The inferior surface, slightly
concave and rough, forms the back part of the hard palate. At its posterior
part may be seen a transverse ridge, more or less marked, for the attachment
of the aponeurosis of the Tensor palati muscle. At the outer extremity of this
ridge is a deep groove converted into a canal by its articulation with the tube-
rosity of the superior maxillary bone, and forming the posterior palatine canal.
Near this groove, the orifices of one or two small canals, accessory posterior
palatine, may frequently be seen. The anterior border is serrated, bevelled at
the expense of its inferior surface, and articulates with the palate process of the
superior maxillary bone. The posterior border is concave, free, and serves for
the attachment of the soft palate. Its inner extremity is sharp and pointed,
and, when united with the opposite bone, forms a projecting process, the poste-
rior nasal spine, for the attachment of the Azygos uvulse. The external border
is united with the lower
Fig. 144. — Left Palate Bone. Internal View (enlarged)
0^^'
/?>/.
Process
part of the perpendicular
plate almost at right an-
gles. The internal border,
the thickest, is serrated
for articulation with its
fellow of the opposite side ;
its superior edge is raised
into a ridge, which united
with the opposite bone,
forms a crest in which the
vomer is received.
The Superior or Vertical
Plate (Fig. IM) is thin, of
an oblong form, and di-
rected upwards and a little
inwards. It presents two
surfaces, an external and
an internal, and four bor-
ders.
The internal surf ace pre-
sents at its lower part a
broad shallow depression,
which forms part of the inferior meatus of the nose. Immediately above this
is a well-marked horizontal ridge, the inferior turbinated crest, for articulation
with the inferior turbinated bone; above this, a second broad shalloAV depression,
which forms part of the middle meatus, surmounted above by a horizontal ridge
loss prominent than the inferior, the superior turbinated crest, for articulation
with tho. middle turbinated bonn. Above the superior turbinated crest is a
rnxYvow liorizontal groove, whidi (i>rins part of the superior meatus.
The external surface is rough and irregular tliroughout the greater part of its
extent, for articulation with the inner surface of the superior maxillary bone,
HORIZOMTAI. rUATE
PALATE BONES.
183
Fig. 145. — Left Palate Bone.
View (enlarged).
Posterior
/„/,„€ T.,'.
ShJtenaitiul /iroccss.
huUt /lorL.
arlicuCeC'r /u/rl.
Rx-i.Su.f.
its upper and back part being smooth where it enters into the formation of the
spheno-maxillar J fossa ; it is also smooth in front, where it covers the orifice of
the antrum. Towards the back part of this surface is a deep groove, converted
into a canal, the posterior palatine, by its articulation with the superior maxil-
lary bone. It transmits the posterior, or descending palatine vessels, and a large
nerve.
The anterior border is thin, irregular, and presents opposite the inferior turbi-
nated crest a pointed projecting lamina, the maxillary process, which is directed
forwards and closes in the lower and back part of the opening of the antrum,
being received into a fissure that exists at the inferior part of this aperture.
The posterior border (Fig. 145) presents a deep groove, the edges of which are
serrated for articulation with the ptery-
goid process of the sphenoid. At the
lower part of this border is seen a pyra-
midal process of bone, the pterygoid pro-
cess or tuberosity of the palate, which is
received into the angular interval be-
tween the two pterygoid plates of the
sphenoid at their inferior extremity.
This process presents at its back part
three grooves, a median and two lateral
ones. The former is smooth, and forms
part of the pterygoid fossa, affording
attachment to the Internal , pterygoid
muscle ; whilst the lateral grooves are
rough and uneven, for articulation with
the anterior border of each pterygoid
plate. A few fibres of the External
pterygoid muscle and of the Superior
constrictor also arise from the tuberosity
of the palate bone. The base of this
process, continuous with the horizontal
portion of the bone, presents the aper-
tures of the accessory descending pala-
tine canals ; whilst its outer surface is rough for articulation with the inner
surface of the body of the superior maxillary bone.
The superior border of the vertical plate presents two well-marked processes
separated by an intervening notch or foramen. The anterior, or larger, is called
the orbital ])TOcess ; the posterior, the sphenoidal.
The Orbital Process^ directed upwards and outwards, is placed on a higher
level than the sphenoidal. It presents five surfaces, which inclose a hollow
cellular cavity, and is connected to the perpendicular plate by a narrow con-
stricted neck. Of these five surfaces, three are articular, two non -articular, or
free surfaces. The three articular are the anterior or maxillary surface, which
is directed forwards, outwards, and downwards, is of an oblong form and rough
for articulation with the superior maxillary bone. The posterior or sphenoidal
surface is directed backwards, upwards, and inwards. It ordinarily presents a
small open cell, which communicates with the sphenoidal sinus, and the margins
of which are serrated for articulation with the vertical part of the sphenoidal
turbinated bone. The internal or ethmoidal surface is directed inwards, upwards,
and forwards, and articulates with the lateral mass of the ethmoid bone. In some
cases, the cellular cavity above mentioned opens on this surface of the bone ; it
then communicates with the posterior ethmoidal cells. More rarely it opens on
both surfaces, and then communicates both with the posterior ethmoidal cells, and
the sphenoidal sinus. The non-articular or free surfaces are the superior or
orbital^ directed upwards and outwards, of triangular form, concave, smooth, and
forming the back part of the floor of the orbit, and the external or zygomatic
Poit.
■^'"ic.
' HORIZONT A U
PLATE
184
THE SKELETON.
surface, directed outwards, backwards, and downwards, of an oblong form, smooth,
lying in the splieno-maxillary fossa, and looking into the zygomatic fossa. The
latter surface is separated from the orbital by a smooth rounded border, which
enters into the formation of the spheno- maxillary fissure.
The Sphenoidal Process of the palate bone is a thin compressed plate, much
smaller than the orbital, and directed upwards and inwards. It presents three
surfaces and two borders. The superior surface, the smallest of the three, articu-
lates with the horizontal part of the sphenoidal turbinated bone ; it presents a
groove which contributes to the formation of the pterygo-palatine canal. The
internal surface is concave, and forms part of the outer wall of the nasal fossa.
The external surface is divided into an articular and a non-articular portion ; the
former is rough for articulation with the inner surface of the pterygoid process
of the sphenoid ; the latter is smooth, and forms part of the zygomatic fossa.
The anterior border forms the posterior boundary of the spheno-palatine fora-
men. The posterior border, serrated at the expense of the outer table, articulates
with the inner surface of the pterj^goid process.
The orbital and sphenoidal processes are separated from one another by a deep
notch, which is converted into a foramen, the spheno-palatine, by articulation
with the sphenoidal turbinated bone. Sometimes the two processes are united
above, and form between them a complete foramen, or the notch is crossed by one
or more spiculse of bone, so as to form two or more foramina. In the articulated
skull, this foramen opens into the back part of the oiiter wall of the superior
meatus, and transmits the spheno-palatine vessels and nerves.
Develop'inent. From a single centre, which makes its appearance at the angle
of junction of the two plates of the bone. From this point ossification spreads
inwards to the horizontal plate, downwards into the tuberosity, and upwards into
the vertical plate. In the foetus, the horizontal plate is much longer than the
vertical ; and even after it is fully ossified, the whole bone is at first remarkable
for its shortness.
Articulations. With six bones ; the sphenoid, ethmoid, superior maxillary, in ■
ferior turbinated, vomer, and opposite palate.
Attachment of Muscles. The Tensor palati, Azygos uvulte, Internal and External
pterygoid, and Superior constrictor of the pharynx.
The Inferioe Turbinated Bones.
The Inferior Turbinated Bones are situated one on each side of the outer wall
of the nasal fossas. Each consists of a layer of thin spongy bone, curled upon
itself like a scroll, hence its name "turbinated;" and extends horizontally along
the outer wall of the nasal fossa, immediately below the orifice of the antrum.
Each bone presents two surfaces, two borders, and two extremities.
Fig. 146. — Right Inferior Turbinated Bone.
Internal Surface.
Fig. 147. — Eight Inferior Turbinated
Bone. Outer Surface.
Tl 10 m^erwr/i.sv.o/ac? (Fig. 146) is convex, perforated by numerous apertures,
and traversed by longitudinal grooves and canals for the lodgment of arteries
and veins. In the recent state it is covered by the lining membrane of the nose.
The external surf ace is concave (Fig. 147), and forms part of the inferior meatus.
VOMER.
185
Its upper border is tliin, irregular, and connected to various bones along tbe
outer wall of the nose. It may be divided into three j3ortions; of these, the
anterior articulates with the inferior turbinated crest of the superior maxillary
bone ; the posterior with the inferior turbinated crest of the palate bone ; the
middle portion of the superior border presents three well-marked processes,
which vary much in their size and form. Of these the anterior and smallest is
situated at the junction of the anterior fourth with the posterior three-fourths
of the bone; it is small and pointed, and is called the lachrymal process^ for it
articulates with the anterior inferior angle of the lachrymal bone, and by its
margins, with the groove on the back of the nasal process of the superior maxil-
lary, and thus assists in forming the lachrymal canal. At the junction of the
two middle fourths of the bone, but encroaching on its posterior fourth, a broad
thin plate, the ethmoidal process^ ascends to join the unciform process of the
ethmoid; from the lower border of this' process a thin lamina of bone curves
downwards and outwards, hooking over the lower edge of the orifice of the
antrum, which it narrows below ; it is called the maxillary process^ and fixes
the bone firmly on to the outer wall of the nasal fossa. The inferior border is
free, thick, and cellular in structure, more especially in the middle of the bone.
Both extremities are more or less narrow and pointed. If the bone is held so
that its outer concave surface is directed backwards (i. e., towards the holder),
and its superior border, from which the lachrymal and ethmoidal processes pro-
ject, upwards, the lachrymal process will be directed to the side to which the
bone belongs.
Develojoment. By a single centre, which makes its appearance about the middle
of foetal life.
Articulations. With four bones: one of the cranium, the ethmoid, and three
of the face, the superior maxillary, lachrymal, and palate,
No muscles are attached to these bones.
The Yomer.
The Vomer is a single bone, situated vertically at the back part of the nasal
fossa?, forming part of the septum of the nose. It is thin, somewhat like a plough-
share in form ; but it varies in difl'erent individuals, being frequently bent to
one or the other side ; it pre-
sents for examination two sur- Fig. 148.— Vomer,
faces and four borders. The
lateral surfaces are smooth,
marked by small furrows for
the lodgment of bloodvessels,
and by a groove on each side
sometimes a canal, the naso-
palatine, which runs obliquely
downwards and forwards to
the intermaxillary suture be-
tween the two anterior pala-
tine canals ; it transmits the
naso-palatine nerve. The su-
perior border, the thickest,
presents a deep groove, boun-
ded on each side by a hori-
zontal projecting ala of bone:
the groove receives the rostrum of the sphenoid, whilst the alse are overlapped
and retained by lamina (the vaginal processes) which project from the under
surface of the body of the sphenoid at the base of the pterygoid processes. At
the front of the groove a fissure is left for the transmission of bloodvessels to
the substance of the bone. The inferior border, the longest, is broad and uneven
in front, where it articulates with the two superior maxillary bones ; thin and
^''^li Suj) -Ma^
186
THE SKELETON.
sharp beliind, where it joins with the palate bones. The upper half of the
anterior border usually consists of two laminae of bone, between which is received
the perpendicular plate of the ethmoid, the lower half consisting of a single
rough edge, also occasionally channelled, which is united to the triangular carti-
lage of the nose. The posterior border is free, concave, and separates the nasal
fossfe behind. It is thick and bifid above, thin below.
Develo'pm.ent. The vomer at an early period consists of two laminae separated
by a very considerable interval, and inclosing between them a plate of cartilage
which is prolonged forwards to form the remainder of the septum. Ossification
commences in it at about the same period as in the vertebrae (the coalescence of
the laminse taking place from behind forwards), but is not complete until after
puberty.
Articulations. With six bones : two of the cranium, the sphenoid and ethmoid ;
and four of the face, the two superior maxillary and the two palate bones, and
with the cartilage of the septum.
The vomer has no muscles attached to it.
The IinTferiof. Maxillaey Bone.
The Inferior Maxillary Bone, the largest and strongest bone of the face, serves
for the reception of the lower teeth. It consists of a curved horizontal portion,
the body, and two perpendicular portions, the rami, which join the back part
of the body nearly at right angles.
The Horizontal ]?ortion, or body (Fig. 149), is convex in its general outline,
and curved somewhat like a horse-shoe. It presents for examination two
Fig. 149. — Inferior Maxillary Bone. Outer Surface. Side View.
pB.'.5-- ,.J . J
_ ^J^
G I'oove Jut jiiriiif csi'f V
Mw"'
surfaces and two borders. Tlic external snrfaee is convex from side to side,
concave from above downwards. In the median line is a vertical ridge, the
sym])hysis, which extends from the upper to tlic lower Tiordcr of tlie bone, and
indicates the pomt of junction of ihc two pieces of which 1he bone is composed
at an early period of life. The lower part of the ridge terminates in a prominent
triangular eminence, the mental process. On either side of the symphysis, just
below the roots of the incisor iccth, is a dey)rcssion, the incisive fossa, for the
attachment of the Levator incnii (or Levator labii inferioris); and still mor(>
externally, a foramen, tlic mental foramen, for the passage of the mental nerve
and artery. This foramen is placed just below the root of the second bicuspid
INFERIOR MAXILLARY BONE.
187
tooth. Eunning outwards from tlie base of the mental process on each side, is
a well-marked ridge, the external oblique line. The ridge is at first nearly
horizontal, but afterwards inclines upwards and backwards, and is continuous
with the anterior border of the ramus; it affords attachment to the Depressor
labii inferioris and Depressor anguli oris, below which the Platysma mjoides is-
inserted.
The internal surface (Fig. 150) is concave from side to side, convex from above
downwards. In the middle line is an indistinct linear depression, corresponding
to the symphysis externally ; on either side of this depression, just below its
centre, are four prominent tubercles, placed in pairs, two above and two below ;
they are called the genial tubercles^ and afford attachment, the upper pair to the
Genio-hyoglossi muscles, the lower pair to the Genio-hyoidei muscles. Some-
times the tubercles on each side are blended into one, or they all unite into an
irregular eminence of bone, or nothing but an irregularity may be seen on the
surface of the bone at this part. On either side of the genial tubercles is an
oval depression, the sublingual fossa, for lodging the sublingual gland; and
Fig. 150. — Inferior Maxillary Bone. Inner Surface. Side View.
CENIO-HVO-GLOSSUS
CENIO-WYOID-US
Mijlo-Jiyoid Eidrje
Bod.
beneath the fossa, a rough depression on each side, which gives attachment to
the anterior belly of the Digastric muscle. At the back part of the sublingual
fossa, the internal oblique line (mylo-hyoidean) commences ; it is at first faintly
marked, but becomes more distinct as it passes upwards and outwards, and is
especially prominent opposite the last two molar teeth ; it affords attachment
throughout its whole extent to the Mylo-hyoid muscle, the Superior constrictor
of the pharynx with the pterygo maxillary ligament, being attached above its
posterior extremity, nearer the alveolar margin. The portion of bone above
this ridge is smooth, and covered by the mucous membrane of the mouth;
whilst that below it presents an oblong depression, the submaxillary fossa,
A\^ider behind than in front, for the lodgment of the submaxillary gland. The
external oblique line and the internal or mylo-hyoidean line divide the body of
the bone into a superior or alveolar, and an inferior or basilar portion.
The superior or alveolar border is wider, and its margins thicker behind than
|n front. It is hollowed into numerous cavities, for the reception of the teeth;
these cavities are sixteen in number, and vary in depth and size according to
the .teeth which they contain. To its outer side, the Buccinator muscle is at-
188 THE SKELETON.
taclied as far forward as tlie first molar tootli. The inferior harder is rounded,
longer than the superior, and thicker in front than behind ; it presents a shallow
groove, just where the body joins the ramus, over which the facial artery turns.
The Perpendicular Portions^ or Rami^ are of a quadrilateral form. Each
presents for examination two surfaces, four borders, and two processes. The
external surface is flat, marked with ridges, and gives attachment throughout
nearly the whole of its extent to the Masseter muscle. The internal surface
presents about its centre the oblique aperture of the inferior dental canal, for
the passage of the inferior dental vessels and nerve. The margin of this open-
ing is irregular ; it presents in front a prominent ridge, surmounted by a sharp
spine, which gives attachment to the internal lateral ligament of the lower jaw ;
and at its lower and back part a notch leading to a groove, the mylo-hyoidean,
which runs obliquely downwards to the back part of the submaxillary fossa ;
and lodges the mylo-hyoid vessels and nerve : behind the groove is a rough
surface for the insertion of the Internal pterygoid muscle. The inferior dental
canal runs obliquely downwards and forwards in the substance of the ramus,
and then horizontally forwards in the body ; it is here placed under the alveoli,
with which it communicates by small openings. On arriving at the incisor
teeth, it turns back to communicate with the mental foramen, giving oft' two
small canals, which run forward, to be lost in the cancellous tissue of the bone
beneath the incisor teeth. This canalj in the posterior two-thirds of the bone,
is situated nearer the internal surface of the jaw ; and in the anterior thixd,
nearer its external surface. Its walls are composed of compact tissue at either
extremity, and of cancellous in the centre. It contains the inferior dental
vessels and nerve, from which branches are distributed to the teeth through
small apertures at the bases of the alveoli. The upper harder of the ramus is
thin and presents two processes, separated by a deep concavity, the sigmoid notch.
Of these processes, the anterior is the coronoid, the posterior the condyloid.
The Coronoid Process is a thin, flattened, triangular eminence of bone, which
varies in shape and size in different subjects, and serves chiefly for the attach-
ment of the Temporal muscle. Its external surface is smooth, and affords
attachment to the Masseter and Temporal muscles. Its internal surface gives
attachment to the Temporal muscle, and presents the commencement of a longi-
tudinal ridge, which is continued to the posterior part of the alveolar process.
On the outer side of this ridge is a deep groove, continued below on the outer
side of the alveolar process ; this ridge and part of the groove afford attach-
ment, iabove, to the Temporal ; below, to the Buccinator muscle.
The Condyloid Process^ shorter but thicker than the coronoid, consists of two
portions : the condyle, and the constricted portion which supports the condyle,
the neck. The condyle is of an oblong form, its long axis being transverse, and
set obliquely on the neck in such a manner that its outer end is a little more
forward and a little higher than its inner. It is convex from before backwards,
and from side to side, the articular surface extending further on the posterior
than on the anterior surface. The neck of the condyle is flattened from before
backwards, and strengthened by ridges which descend from the fore part and
sides of tlie condyle. Its lateral margins arc narrow, and present externally a
tubercle for tlic external lateral ligament. Its joosterior surface is convex; its
anterior is hollowed out on its inner side by a depression (the pterygoid fossa)
for the attachment of the External pterygoid.
The lovjer harder of the ramus is thick, straight, and continuous with the
body of the bone. At its junction with the posterior border is the angle of the
jaw, which is eitlicr inverted or everted, and marked by rough oblique ridges
on each side for the attachment of the Masseter externally, and the Internal
pterygoid internally; the stylo-maxillary ligament is attached to the bone
between these muscles. Tlie anterior hord.or is thin above, thick' cr below, and
continuous with the extern ;il oblique line. The posterior harder is thick, smooth,
rounded, and covered by the par(;tid gland.
INFERIOR MAXILLARY BONE.
Side View of the lower jaw at different Periods of Life.
Fig. 151.— At Birth.
189
Fig. 152. — At Puberty.
Fig. 153. -In the Adult.
Fig. 154.— In old Age.
190 THE SKELETON.
The Sigmoid Notch, separating the two processes, is a deep semilunar depres-
sion, crossed by tlie masseteric artery and nerve.
Development. This bone is formed at such an early period of life, before,
indeed, any other bone except the clavicle, that it has been found impossible at
present to determine its earliest condition. It appears probable, however, that
it is developed by two centres, one for each lateral half, the two segments meet-
ing at the symphysis, where they become united. Additional centres have also
been described for the coronoid process, the condyle, the angle, and the thin
plate of bone which forms the inner side of the alveolus.
Changes produced in the Lower Jaw by Age.
The changes which the Lower Jaw undergoes after birth relate — 1. To the alterations effect-
ed in the body of the bone by the first and second dentitions, the loss of the teeth in the aged,
and the subsequent absorption of the alveoli. 2. To the size and situation of the dental canal ;
and, 3. 'I'o the angle at which the ramus joins with the body.
Al birth (Fig. 151), the bone consists of twt) lateral halves, united by fibro-cartilaginous tissue,
in which one or two osseous nuclei are generally found. The body is a mere shell of bone, con-
taining the sockets of the two incisor, the canine, and the two temporary molar teeth, imperfectly
partitioned from one another. The dental canal is of large size, and runs near the lower border
of the bone, the mental ibramen opening beneath the socket of the first molar. The angle is
obtuse, from the jaws not being as yet separated by the eruption of the teeth.
After birth (Fig. 152), the two segments of the bone become joined at the symphysis, from
below upwards, in the first year ; but a trace of separation may be visible in the beginning of
the second year, near the alveolar margin. 'J'he body becomes elongated in its whole length,
but more especially behind the mental foramen, to provide space for the three additional teeth
developed in this part. The depth of the body becomes greater, owing to increased growth of
the alveolar part, to afford room for the fangs of the teeth, and by thickening of the subdental
])ortion which enables the jaw to withstand the powerful action of the masticatory muscles; but
the alveolar portion is the deeper of the two, and consequently, the chief part of the body lies
above the oblique line. The dental canal, after the second dentition, is situated just above the
level of the mylo-hyoid ridge; and the mental foramen occupies the position usual to it in the
adult. The angle becomes less obtuse, owing to the separation of the jaws bj' the teeth.
In the adult (Fig. 153), the alveolar and basilar portions of the body ai'e usually of equal
depth. The mental foramen opens midway between the upper and lower border of the bone, and
the dental canal runs nearly parallel with the mylo-hyoid Hue. The ramus is almost vertical in
direction, and joins the body nearly at right angles.
In -old age (Fig. 154), the bone becomes greatly reduced in size; for, with the loss of the
teeth, the alveolar process is absorbed, and the basilar part of the bone alone remains ; conse-
quently the chief part of the bone is below the oblique line. The dental canal, with the mental
foramen opening from it, is close to the alveolar border. 'J'he rami are oblique in direction, and
the angle obtuse.
Articulations. With the glenoid fossas of the two temporal bones.
Attachment of Muscles. To its external surface, commencing at the symphy-
sis, and proceeding backwards : Levator menti. Depressor labii inferioris. De-
pressor anguli oris, Platysma myoides, Buccinator, Masseter : a portion of the
C)rbicularis oris (Accessorii orbicularis inferiores) is also attached to this sur-
face. To its internal surface, commencing at the same point : Genio-hyo-glossus,
Genio-hyoideus, Mylo-hyoideus, Digastric, Superior constrictor, Temporal,
Internal pterygoid, External pterygoid.
THE SUTURES.
The bones of the cranium and face arc connected to eacb other by means of
sutures. The sutures are rows of dentated processes of bone projecting from the
edge of cither bone, and locking into each other : the dentations, however, are
confined to the external table, the edges of the internal tabic lying merely in
apposition. The Cranial Sutures wv.iy ho. (\Wu\oA into three sets: 1, Those at-
the vertex of the skull. 2. Those at ihc side of ihe sknll. 3. Those at the
Ijase,
The sutures at the vertex of the skull are three: the sagittal, coronal, and
lainbdoid.
THE SUTURES. 191
The Sagittal Suture (interparietal) is formed by tlie junction of tlae two parietal
bones, and extends from the middle of the frontal bone, backwards to the supe-
rior ancle of the occipital. In childhood and occasionally in the adult, when
the two halves of the frontal bone are not united, it is continued forwards to the
root of the nose. This suture sometimes presents, near its posterior extremity,
the parietal foramen on each side ; and in front, where it joins the coronal
suture, a space is occasionally left, which incloses a large Wormian bone.
The Coronal Suture [fronto-parietal) extends transversely across the vertex of
the skull, and connects the frontal with the parietal bones. It commences at
the extremity of the great wing of the sphenoid on one side, and terminates at
the same point on the opposite side. The dentations of this suture are more
marked at the sides than at the summit, and are so constructed that the frontal
rests on the parietal above, whilst laterally the frontal supports the parietal.
The Lamhdoid Suture {pccipito -parietal)^ so called from its resemblance to the
Greek letter a, connects the occipital with the parietal bones. It commences on
each side at the mastoid portion of the temporal bone, and inclines upwards to
the end of the sagittal suture. The dentations of this suture are very deep and
distinct, and are often interrupted by several small Wormian bones.
The sutures at the side of the skull are also three in number : the spheno-
parietal, squamo-parietal, and masto-parietal. They are subdivisions of a single
suture, formed between the lower border of the parietal, and the temporal and
sphenoid bones, and which extends from the lower end of the lambdoid suture
behind, to the lower end of the coronal suture in front.
The Splieno-parietal is very short; it is formed by the tip of the great wing
of the sphenoid, which overlays the anterior inferior angle of the parietal bone.
The Squamo-parietal^ or squamous suture, is arched. It is formed by the
squamous portion of the temporal bone overlapping the middle division of the
lower border of the parietal.
The Masto-parietal is a short suture, deeply dentated, formed by the posterior
inferior angle of the parietal, and the superior border of the mastoid portion of
the temporal.
The sutures at the base of the skull are, the basilar in the centre, and on each
side, the petro-occipital, the masto-occipital, the petro-sphenoidal, and the
squamo-sphenoidal.
The Basilar Suture is formed by the junction of the basilar surface of the
occipital bone with the posterior surface of the body of the sphenoid. At an
early period of life, a thin plate of cartilage exists between these bones ; but in
the adult they become fused into one. Between the outer extremity of the
basilar suture, and the termination of the lambdoid, an irregular suture exists,
which is subdivided into two portions. The inner portion, formed by the union
of the petrous part of the temporal with the occipital bone, is termed the petro-
occipital. The outer portion, formed by the junction of the mastoid part of the
temporal with the occipital, is called the masto-occipital. Between the bones
forming the petro-occipital suture, a thin plate of cartilage exists ; in the masto-
( occipital is occasionally found the opening of the mastoid foramen. Between
the outer extremity of the basilar suture and the spheno-parietal, an irregular
isuture may be seen, formed by the union of the sphenoid with the temporal
l)one. The inner and smaller portion of this suture is termed the petro-sphenoi-
dal; it is formed between the petrous portion of the temporal and the great
wing of the sphenoid; the outer portion, of greater length, and arched, is formed
between the squamous portion of the temporal and the great wing of the sphe-
noid : it is called the squamo-sphenoidal.
The cranial bones are connected with those of the face, and the facial bones
with each other, by numerous sutures, which, though distinctly marked, have
received no special names. The only remaining suture deserving especial con-
sideration, is the transverse. This extends across the upper part of the face, and
IS termed by the junction of the frontal with the facial bones : it extends from
192 THE SKELETON.
tlie external angular process of one side, to tlie same point on tlie opposite side,
and connects the frontal with tlie malar, the sphenoid, the ethmoid, the lachrymal,
the superior maxillary, and the nasal bones on each side.
The sutures remain separate for a considerable period after the complete for-
mation of the skull. It is probable that they serve the purpose of permitting
the growth of the bones at their margins ; while their pecu.liar formation,
together with the interposition of the sutural ligament between the bones form-
ing them, prevents the dis|)ersion of blows or jars received upon the skull. Dr.
Humphry remarks, "■ that, as a general rule, the sutures are first obliterated at
the parts in which the ossification of the skull was last completed, viz., in the
neighborhood of the fontanelles ; and the cranial bones seem in this respect to
observe a similar law to that which regulates the union of the epiphyses to the
shafts of the lona; bones." The same author remarks that the time of their dis-
appearance is extremely variable : they are sometimes found well-marked in
skulls edentulous with age, while in others which have only just reached matu-
rity they can hardly be traced.
THE SKULL.
The Skull, formed by the union of the several cranial and facial bones already
described, when considered as a whole, is divisible into five regions : a superior
region or vertex, an inferior region or base, two lateral regions, and an anterior
region, the face.
Vertex of the Skull.
The Superior Eegion, or Ycrtex, presents two surfaces, an external and an in-
ternal.
The External Surface is bounded, in front, by the nasal eminences and super-
ciliary ridges ; behind, by the occipital protuberance and superior curved lines
of the occipital bone ; laterally, by an imaginary line extending from the outer
end of the superior curved line, along the temporal ridge, to the external angu-
lar process of the frontal. This surface includes the vertical portion of the
frontal, the greater part of the parietal, and" the superior third of the occipital
bone ; it is smooth, convex, of an elongated oval form, crossed transversely by
the coronal suture, and from before backwards by the sagittal, which terminates
behind in the lambdoid. From before backwards may be seen the frontal emi-
nences and remains of the suture connecting the two lateral halves of the frontal
bono ; on each side of the sagittal suture are the joarietal foramen and parietal emi-
nence, and still more posteriorly the smooth convex surface of the occipital bone.
The Internal Surface is concave, presents eminences and depressions for the
convolutions of the cerebrum, and numerous furrows for the lodgment of branches
of the meningeal arteries. Along the middle line of this surface is a longitudinal
groove, narrow in front, where it terminates in the frontal crest ; broader behind ;
it lodges tlie superior longitudinal sinus, and its margin aflbrds attachment to
the falx cerebri. ()\\ cither side of it are several depressions for the Pacchionian
bodies, and at its back part, the internal openings of the jiarietal foramina. This
surface is crossed, in front, by the coronal suture; JVom before backwards, by
the sagittal ; beliiiid, by llie lambdoid.
Base oe Tir]<; Skitij..
Tlio TiiH iImi- llcgion, or. Base of the skull, ])re'sents two surfaces, an inlcrnal
or cerebral, and an external or basilar.
The Trdernal or Cerehral Surface (Fig. 155) presents ihi'oo. fossa?, on each side,
called the anterior, middle, and jinsterior fosstc of the cranium.
The Anterior Fossais formed by the orbital plate of the iionjal, the cribi'iforni
BASE OF THE SKULL.
193
plate of tlie etlimoid, the etlimoidal spine and lesser wing of the sphenoid. It is
the most elevated of the three fossas, convex externally where it corresponds to
the roof of the orbit, concave in the median line in the situation of the cribri-
form plate of the ethmoid. It is traversed bj three sutures, the ethmoido-fron-
tal, ethmo-sphenoidal, and fronto-sphenoidal ; and lodges the anterior lobe of
the cerebrum. It presents, in the median line, from before backwards, the com-
Fiff. 1.55. — Base of the Skull. Inner or Cerebral Surface.
Grnoi>e for Stijv.r. lonaitud.Sinus
Grooves for Atttf/r. M«mnyealA"-
Foram£7i, Cxfitm
Criixtn, GfrU.i
Slit fov iK'ti.xa.l 7urif',
Crvoovb j nT Kn,j:nX 'nr.-rvti.
Anterior 2!thmoidnl£uT..
Orifwes for Olfact/yry vcrt-es
FoAterior E^iiiiQidul lor,
TithmoLcial Spine
OlfactdT]! CrTOoircsr-
OjjttB TPoravte/f
Optic Groove-
Oliitcry pfooi-
Aiiterwr ClCiujid prac
Middle, Cluioid proc
Posterior Clinm'J, joroo.
Groove -foT 0':) neri's
For-'i laeei'um. media ni.
OrCfLce of Carotid Canal
DepitSiCon for Casscrian Gamglian
Iltafus Auditor. Internus
Slit for Dwra-Mat.er
jS'up. Fetro^al grpoj's
I'nr. Jaceram paaterius
Anterior Condyloid Tcr.
Aqueduct. Vestibu.li
Poitte^ior Condyloid For.
Mastoid Fnn-
JCost. MoiUiLqeal Groocc
13
194 THE SKELETON.
mencement of tlie groove for tlie superior longitudinal sinus, and tlie crest for
the attaclLment of the falx cerebri ; the foramen crecum, an aperture formed by
the frontal bone and the crista galli of the ethmoid, which, if pervious, trans-
mits a small vein from the nose to the superior longitudinal sinus ; behind the
foramen cfecum, the crista galli, the posterior margin of which affords attach-
ment to the falx cerebri ; on either side of the crista galli, the olfactory groove,
which supports the bulb of the olfactory nerve, and is perforated by three rows
of orifices for its filaments, and in front by a slit-like opening, for the nasal
branch of the ophthalmic nerve. On the outer side of each olfactory groove are
the internal openings of the anterior and posterior ethmoidal foramina ; the
former, situated about the middle of the outer margin of the olfactory groove,
transmits the anterior ethmoidal artery and the nasal nerve, which runs in a
depression along the surface of the ethmoid, to the slit-like opening above men-
tioned ; whilst the posterior ethmoidal foramen opens at. the back part of this
margin under cover of the projecting lamina of the sphenoid, and transmits the
posterior ethmoidal artery and vein to the posterior ethmoidal cells. Further
back in the middle line is the ethmoidal spine, bounded behind by an elevated
ridge, separating a longitudinal groove on each side which supports the olfactory
nerve. The anterior fossa presents laterally eminences and depressions for the
convolutions of the brain, and grooves for the lodgment of the anterior menin-
geal arteries.
The Middle Fossa, somewhat deeper than the preceding, is narrow in the
middle and becomes wider as it expands laterally. It is bounded in front by
the posterior margin of the lesser wing of the sphenoid, the anterior clinoid
process, and the anterior margin of the optic groove; behind, by the upper
border of the petrous portion of the temporal, and basilar suture ; externally, by
the squamous portion of the temporal, and anterior inferior angle of the parietal
bone, and is separated from its fellow by the sella Turcica. It is traversed b}'' four
sutures, the squamous, spheno-parietal, spheno-temporal, and petro-sphenoidal.
In the middle line, from before backwards, is the optic groove, which supports
the optic commissure, and terminates on each side in the optic foramen, for the
passage of the optic nerve and o|)hthalmic artery ; behind the optic groove is the
olivary process, and lateralh' the anterior clinoid processes, to which are attached
the f )lds of the dura mater, which form the cavernous sinuses. Separating the
middle fossae is the sella Turcica, a deep depression, which lodges the pituitary
gland, bounded in front by a small eminence on either side, the middle clinoid
process, and behind by a broad square plate of bone, surmounted at each superior
angle by a tubercle, the posterior clinoid process ; beneath the latter process is a
groove, for the sixth nerve. On each side of the sella Turcica is the cavernous
groove; it is broad, shallow, and curved somewhat like the italic letter/; it
commences behind at the foramen laccrum medium, and terminates on the inner
side of the anterior clinoid process. This groove lodges the cavernous sinus, the
internal carotid artery, and the nerves of the orbit. The sides of the middle
fossa are of considerable depth ; they present eminences and depressions for the
middle lobes of the brain, and grooves for the branches of the middle meningeal
artery; the latter commence on the outer side of the foramen spinosum, and
consist of two large branches, an anterior and a posterior; the fanner passing
upwards and forwards to the anterior inferior angle of the parietal bone, the
latter passing upwards and backwards. The following foramina may also be
seen from before backwards. Most anteriorly is the foramen lacerum antcrius,
or splicnoidal fissure, formed, above by the lesser wing of the sphenoid; below
by the greater wing; internally, by the body of the s]-)hcn<)id; and completed
externaliy by tlic ()rl)i1al plate of the frontal b(_)nc. It transmits the third, fourth,
the throe, branches of the o|)htlialmic division of the tifth, the sixth, nerve, and
the ophthalniic vein. Behind the inner extremity of the sphenoidal fissiire is
the foramen rotundum, for the passage of the second division of the fifth or
BASE OF THE SKULL. 195
superior maxillary nerve; still more posteriorly is seen a small orifice, tlie
foramen Yesalii, an opening, situated between tlie foramen rotundum and ovale,
a little internal to both; it varies in size in different individuals, and is often
absent ; wlien present, it transmits a small vein. It opens below in tbe pterygoid
fossa, just at the outer side of tlie scaphoid depression. Behind and external to
the latter opening is the foramen ovale, which transmits the third division of
the fifth or inferior maxillary nerve, the small meningeal artery, and the small
petrosal nerve. On the outer side of the foramen ovale is the foramen spinosum,
for the passage of the middle meningeal artery; and on the inner side of the
foramen ovale, the foramen lacerum medium. The lower part of this aperture is
filled up with cartilage in the recent state. On the anterior surface of the petrous
portion of the temporal bone is seen, from without inwards, the eminence caused
by the projection of the superior semicircular canal, the groove leading to the
hiatus Fallopii, for the transmission of the petrosal branch of the Vidian nerve ;
beneath it, the smaller groove, for the passage of the smaller petrosal nerve; and,
near the apex of the bone, the depression for the Casserian ganglion, and the
orifice of the carotid canal, for the passage of the internal carotid artery and
carotid plexus of nerves.
The Posterior Fossa, deeply concave, is the largest of the three, and situated
on a lower level than either of the preceding. It is formed by the occipital, the
petrous and mastoid portions of the temporal, and the posterior inferior angle of
the parietal bone: is crossed by three sutures, the petro-occipital, masto- occipital,
and masto-parietal ; and lodges the cerebellum, pons Varolii, and medulla oblon-
gata. It is separated from the middle fossa in the median line by the basilar
suture, and on each side by the superior border of the petrons portion of the
temporal bone. This border serves for the attachment of the tentorium cerebelli,
is grooved externally for the superior petrosal sinus, and at its inner extremity
presents a notch, upon which rests the fifth nerve. The circumference of the
fossa is bounded posteriorly by the grooves for the lateral sinuses. In the centre
of this fossa is the foramen magnum, bounded on either side by a rough tubercle,
which gives attachment to the odontoid ligaments; and a little above these are
seen the internal openings of the anterior condyloid foramina. In front of the
foramen magnum is the basilar process, grooved for the support of the medulla
oblongata and pons Varolii, and articulating on each side with the petrous
portion of the temporal bone, forming the petro-occipital suture, the anterior
half of which is grooved for the inferior petrosal sinus, the posterior half being
encroached upon by the foramen lacerum posterius, or jugular foramen. This
foramen is partially subdivided into two parts; the posterior and larger division
transmitting the internal jugular vein and meningeal branches of the ascending
pharyngeal and occipital arteries, the anterior the eighth pair of nerves. Above
the jugular foramen is the internal auditory foramen, for the facial and auditory
nerves aud auditory artery; behind and external to this is the slit-like opening
leading into the aquaeductus vestibuli ; whilst between the two latter, and near
the superior border of the petrous portion, is a small triangular depression which
lodges a process of the dura mater, and occasionally transmits a small vein into
the substance of the bone. Behind the foramen magnum are the inferior occipital
fossae, which lodge the hemispheres of the cerebellum, separated from one another
by the internal occipital crest, which serves for the attachment of the falx cere-
belli, and lodges the occipital sinuses. The posterior foss» are surmounted,
above, by the deep transverse grooves for the lodgment of the lateral sinuses.
These channels, in their passage outwards, groove the occipital bone, the posterior
inferior angle of the parietal, the mastoid portion of the temporal, and the occi-
pital just behind the jugular foramen, at the back part of which they terminate.
Where this sinus grooves the mastoid part of the temporal bone, the orifice of
the mastoid foramen may be seen; and, just previous to its termination, it has
opening into it the posterior condyloid foramen. Neither foramen is constant.
The External Surface of the base of the skull (Fig. 156) is extremely irregular.
196
THE SKELETON.
It is bounded in front by tlie incisor teetb in the upper jaws; behind, by tbe
superior curved lines of tlie occipital bone; and laterally by tbe alveolar arch,
Fiff. 156.— Base of the Sknll. External Surface.
Ant. palci/tLn£ fossa
'mnsmits left Nnso-yalat. n.
Transmits Ant- palat r'Ms.
-Trammits right Nasopalal. n.
AectssoTy 'paZatLTiB
Foramina.
■Po^t.Nccsal S_puie.
AZVaOS UVUL/E
Kamular ^roc:
Sp7ie7toid.proc, of PaLt^te.
'TteTijqp-vcuLatiiie, C
TEMSCR TVMPANI.
FJiaryni/cal Spi-iie.fur sup. constriCE
LAXATOR TVMPANI.
Ccnuil for Jacoiismi's «.
"Axfucduct, CucJiUa...
"For. lace rtt. 77iposte-r/xi s.
CuiimI i'inrJlrnolWs 21.
AuTicular J'issure-
BASE OF THE SKULL. 197
the lower border of tlie malar bone, the zjgoma, and an imaginary line, extending
from the zjgoma to the mastoid process and estremit}^ of the superior curved
line of the occiput. It is formed b}^ the palate processes of the superior maxillary
and palate bones, the vomer, the pterygoid processes, under surface of the great
wing, spinous processes and part of the body of the sphenoid, the under surface
of the squamous, mastoid, and petrous portions of the temporal, and the under
surface of the occipital bone. The anterior part of the base of the skull is raised
above the level of the rest of this surface (when the skull is turned over for the
purpose of examination), surrounded by the alveolar process, which is thicker
behind than in front, and excavated by sixteen depressions for lodging the teeth
of the upper jaw; the cavities varying in depth and size according to the teeth
they contain. Immediately behind the incisor teeth is the anterior palatine fossa.
At the bottom of this fossa may usually be seen four apertures, two placed
laterally, which open above, one in the floor of each nostril, and transmit the
anterior palatine vessels, and two in the median line of the intermaxillary suture,
one in front of the other, the anterior transmitting the left, and the posterior (the
larger) the right naso-palatine nerve. These two latter canals are sometimes
wanting, or they may join to form a single one, or one of them may open into
one of the lateral canals above referred to. The palatine vault is concave,
uneven, perforated by numerous foramina, marked by depressions for the palatal
glands, and crossed by a crucial suture, formed by the junction of the four bones
of which it is composed. One or two small foramina, in the alveolar margin
behind the incisor teeth, occasionally seen in the adult, almost constant in young
subjects, are called the incisive foramina; they transmit nerves and vessels to
the incisor teeth. At each posterior angle of the hard palate is the posterior
palatine foramen, for the transmission of the posterior palatine vessels and
descending palatine nerve, and running forwards and inwards from it a groove,
which lodges the same vessels and nerve. Behind the posterior palatine foramen
is the tuberosity of the palate bone, perforated by one or more accessory pos-
terior palatine canals, and marked by the commencement of a ridge, which runs
transversely inwards, and serves for the attachment of the tendinous expansion
of the Tensor palati muscle. Projecting backwards from the centre of the pos-
terior border of the hard palate is the posterior nasal spine, for the attachment
of the Azygos uvulse. Behind and above the hard palate is the posterior aper-
ture of the nares, divided into two parts by the vomer, bounded above by the
body of the sphenoid, below by the horizontal plate of the palate bone, and
laterally by the pterygoid processes of the sphenoid. Each aperture measures
about an inch in the vertical, and half an inch in the transverse direction. At
the base of the vomer may be seen the expanded alte of this bone, receiving
between them the rostrum of the sphenoid. Near the lateral margins of the
vomer, at the root of the pterygoid processes, are the pterygo-palatine canals.
The pterygoid process, which bounds the posterior nares on each side, presents
near its base the pterygoid or Yidian canal, for the Yidian nerve and artery.
Bach process consists of two plates, which bifurcate at the extremity to receive
the tuberosity of the palate bone, and are separated behind by the pterygoid
fossa, which lodges the Internal pterygoid muscle. The internal plate is long and
narrow, presenting on the outer side of its base the scaphoid fossa, for the origin
of the Tensor palati muscle, and at its extremity the hamular process, around
which the tendon of this muscle turns. The external pterygoid plate is broad,
forms the inner boundary of the zygomatic fossa, and affords attachment, by its
outer surface, to the External pterygoid muscle.
Behind the nasal fossee in the middle line is the basilar surface of the occipital
bone, presenting in its centre the pharyngeal spine for the attachment of the
Superior constrictor muscle of the pharynx, with depressions on each side for
the insertion of the Rectus capitis anticus major and minor. At the base of the
external pterygoid plate is the foramen ovale ; behind this, the foramen spinosum,
and the prominent spinous process of the sphenoid, which gives attachment to
198 THE SKELETON.
tlie internal lateral ligament of tlie lower jaw and tlie Laxator tjmpani muscle.
External to the spinous process is the glenoid fossa, divided into two parts by
the Glaserian iissure (p. 160), the anterior portion concave, smooth, bounded in
front by the eminentia articularis, and serving for the articulation of the condyle
of the lower jaw ; the posterior portion rough, bounded behind by the vaginal
process, and serving for the reception of part of the parotid gland. Emerging
from between the laminse of the vaginal process is the styloid process ; and at
the base of this process is the stylo-mastoid foramen, for the exit of the facial
nerve, and entrance of the stylo-mastoid artery. External to the stylo-mastoid
foramen is the auricular iissure for the auricular branch of the pneumogastric,
bounded behind by the mastoid process. Upon the inner side of the mastoid
process is a deep groove, the digastric fossa ; and a little more internally, the
occipital groove, for the occipital artery. At the base of the internal pterygoid
plate is a large and somewhat triangular aperture, the foramen lacerum medium,
bounded in front by the great wing of the sphenoid, behind by the apex of the
petrous portion of the temporal bone ; and internally by the body of the sphe-
noid and basilar process of the occipital bone ; it presents in front the posterior
orifice of the Vidian canal, behind, the aperture of the carotid canal. The
basilar surface of this opening is filled up in the recent state by a fibro-cartila-
ginous substance ; across its upper or cerebral aspect pass the internal carotid
artery and Vidian nerve. External to this aperture, the petro-sphenoidal suture
is observed, at the outer termination of which is seen the orifice of the canal
for the Eustachian tube, and that for the Tensor tympani muscle. Behind this
suture is seen the under surface of the petrous jDortion of the temporal bone,
presenting, from within outwards, the quadrilateral rough surface, part of which
affords attachment to the Levator palati and Tensor tympani muscles ; external
to this surface the orifices of the carotid canal and the aqueeductus cochleas, the
former transmitting the internal carotid artery and the ascending branches of
the superior cervical ganglion of the sympathetic, the latter serving for the
jDassage of a small artery and vein to the cochlea. Behind the carotid canal is
a large aperture, the jugular fossa, formed in front by the petrous portion of the
temporal, and behind by the occipital ; it is generally larger on the right than
on the left side ; and towards the cerebral aspect is divided into two parts by a
ridge of bone, which projects usually from the temporal ; the anterior, or smaller
portion, transmitting the three divisions of the eighth pair of nerves, the poste-
rior transmitting the internal jugular vein and the ascending meningeal vessels,
from the occipital and ascending pharyngeal arteries. On the ridge of bone
dividing the carotid canal from the jugular fossa, is the small foramen for the
transmission of the tympanic nerve ; and on the outer wall of the jugular fora-
men, near the root of the styloid process, is the small aperture for the trans-
mission of Arnold's nerve. Behind the basilar surface of the occipital bone is
the foramen magnum, bounded on each side by the condyles, rough internally
for the attachment of the alar ligaments, and presenting externally a rough sur-
face, the jugular process, which serves for the attachment of the Rectus lateralis.
On cither side of each condyle anteriorly is the anterior condyloid fossa; perfo-
rated by the anterior condyloid foramen, for the passage of the hypoglossal
nerve. Behind each condyle are the posterior condyloid fossa), perforated on
one or both sides by the posterior condyloid foramina, for the transmission of a
vein to the lateral shius. Behind the foramen magnum is the external occipital
crest, terminating a1)ove at the external occipital protuberance, whilst on each
side arc seen the superior and inferior curved lines ; these, as well as tlie surfaces
of the bone between them, being rough for the attachment of the muscles, which
arc enumerated on page 154.
TEMPORAL FOSSA.
199
Lateral Eegion of the Skull.
Tlie Lateral Region of tlie skull is of a somewliat triangular form, tlie base
of th.e triangle being formed by a line extending from the external angular
process of the frontal bone along tbe temporal ridge backwards to the outer
extremity of tbe superior curved line of the occiput : and tlie sides by two lines,
tile one drawn downwards and backwards from tbe external angular process of
tke frontal bone to the angle of tbe lower jaw, tbe other from the angle of the
jaw upwards and backwards to the extremity of the superior curved line. Th:s
region is divisible into three portions, temporal, mastoid, and zygomatic.
The Temporal Fossa.
The Temporal Fossa is bounded above and behind by the temporal ridge,
which extends from the external angular process of the frontal upwards and
backwards across the frontal and parietal bones, curving downwards behind to
terminate at the posterior root of the zygomatic process. In front, it is bounded
by the frontal, malar, and great wing of the sphenoid : externally, by the zygo-
matic arch, formed conjointly by the malar and temporal bones ; below, it is
Fiir. 157.— Side View of the Skull.
FTonlal
_Parietal
separated from the zygomatic fossa by the pterygoid ridge, seen on the outer
surface of the great wing of the sphenoid. This fossa is formed by five bones,
part of the frontal, great wing of the sphenoid, parietal, squamous portion of
the temporal, and malar bones, and is traversed by five sutures, the tranverse
•200 THE SKELETON.
facial, coronal, spheno-parietal, squamo-parietal and squamo-splienoiclal. It is
deeply concave in front, convex behind, traversed hj grooves wliicli lodge
branches of the deep temporal arteries, and filled by the Temporal . muscle.
The Mastoid Portion of the side of the sknll is bounded in front by the ante-
rior root of the zygoma ; above, by a line which runs from the posterior root of
the zygoma to the end of the masto-parietal suture ; behind and below, by the
masto- occipital suture. It is formed by the mastoid and part of the squamous
and petrous portions of the temporal bone ; its surface is convex and rough for
the attachment of muscles, and presents, from behind forwards, the mastoid
foramen, the mastoid process, the external auditory meatus, surrounded by the
auditory process, and, most anteriorly, the glenoid fossa, bounded in front by
the eminentia articularis, behind by the vaginal process.
The Zygomatic Fossa.
The Zygomatic Fossa is an irregularly shaped cavity, situated below, and on
the inner side of the zygoma; bounded, in front, by the tuberosity of the supe-
rior maxillary bone and the ridge which descends from its malar process ; behind,
by the posterior border of the pterygoid process ; above, by the pterygoid ridge
on the outer surface of the great wing of the sphenoid and squamous portion of
the temporal ; below, by the alveolar border of the superior maxilla ; inter-
nally, by the external pterygoid plate ; and externally, by the zygomatic arch
and ramus of the jaw. It contains the lower part of the Temporal, the External,
and Internal pterygoid muscles, the internal maxillary artery, the inferior
maxillary nerve, and their branches. At its upper and inner part may be
observed two fissures, the spheno-maxillary and pterygo-maxillary.
The Spheno-maxillary fissure, horizontal in direction, opens into the outer and
back part of the orbit. It is formed above by the lower border of the orbital
surface of the great wing of the sphenoid ; below, by the external border of the
orbital surface of the superior maxilla and a small part of the palate bone;
■externally, by a small part of the malar bone ; internally, it joins at right angles
with the pterygo-maxillary fissure. This fissure opens a communication from
the orbit into three fossee, the temporal, zygomatic, and spheno-maxillary ; it
transmits the superior maxillary nerve and its orbital branch, the infraorbital
.artery, and ascending branches from Meckel's ganglion.
The Pterygo-maxillary fissure is vertical, and descends at right angles from
the inner extremity of the preceding; it is an elongated interval, formed by
the divergence of the superior maxillary bone from the pterygoid process of
the sphenoid. It serves to connect the spheno-maxillary fossa with the zygo-
matic, and transmits branches of the internal maxillary artery. It forms tlie
entrance from the zygomatic fossa to
The Spheno-maxillary Fossa.
The Spheno-maxillary Fossa is a small triangular space situated at the angle
of junction of tlic spheno-maxillary and pterygo-maxillary fissures, and placed
beneath the apex of the orbit. It is formed above by tlic under surface of the
body of the sphenoid or by the orbital plate of the palate bone; in front, by
the superior maxillary bone ; behind, by the pterygoid process of the sphenoid ;
internally, by the vertical plate of the palate. This fossa has three fissures
terminating in it, the sphenoidal, spheno-maxillary, and pterygo-maxillary : it
commimicatcs with throe fossos, the orbital, nasal, and zygomatic, and with the
cavity of tlic cranium, and lias opening into it five foramina. Of these there are
three on tlic posterior wall ; the foramen rot,undum above ; below, and internal
to this, the Vidian, and still more inferior and internal, the ]-)terygo-palatine. On
the inner wall is the sphono-palatine for:inicii by whicli the spheno-maxillary
communicates with the nasal fossa, and below is the superior orifice of the poste-
ANTERIOR REGION OF THE SKULL.
201
rior palatine canal, besides occasionally tlie orifices of two or three accessory
posterior palatine canals.
Anterior Region of the Skull,
The Anterior Region of the skull, which forms the face, is of an oval form,
presents an irregular surface, and is excavated for the reception of the two prin-
cipal organs of sense, the eye and the nose. It is bounded above by the nasal
eminences and margins of the orbit ; below, by the prominence of the chin ; on
each side, by the malar bone, and anterior margin of the ramus of the jaw. In
the median line are seen from above downwards, the nasal eminences, which
indicate the situation of the frontal sinuses; and diverging from which are the
superciliary ridges which support the eyebrows. Beneath the nasal eminences
is the arch of the nose, formed by the nasal bones, and the nasal processes of
the superior maxillary. The nasal arch is convex from side to side, concave
from above downwards, presenting in the median line the internasal suture,
formed between the nasal bones, laterally the naso-maxillary suture, formed
Fig. 158. — Anterior Eegion of the Skull.
TENDO OCULI
Ant. Nasal SpiiLc'^^i.,r~~
Jncislve, fossa — \ —
between the nasal bone and the nasal process of the superior maxillary bone,
both these sutures terminating above in that part of the transverse suture which
connects the nasal bone and nasal processes of the superior maxillary with the
frontal. Below the nose is seen the opening of the anterior nares, which i?
202 THE SKELETON.
heart-sliapecl, witTi the narrow end upwards, and presents laterally tlie thin,
sharp margins serving for the attachment of the lateral cartilages of the nose,
and in the middle line below, a prominent process, the anterior nasal spine,
bounded by Uvo deep notches. Below this is the intermaxillary suture, and on
each side of it the incisive fossa. Beneath this fossa is the alveolar process of the
upper and lower jaw, containing the incisor teeth, and at the lower part of the
median line, the symphysis of the chin, the mental eminence, and the incisive
fossa of the lower jaw.
On each side, proceeding from above downwards, is the supraorbital ridge,
terminating externally in the external angular process at its junction with the
malar, and internally in the internal angular process; towards the inner third
of this ridge is the supraorbital notch or foramen, for the passage of the supra-
orbital vessels and nerve, and at its inner side a slight depression for the attach-
ment of the pulley of the Superior oblique muscle. Beneath the supraorbital
ridge is the opening of the orbit, bounded externally by the orbital ridge of the
malar bone ; below, by the orbital ridge formed by the malar, superior maxil-
lary, and lachrymal bones ; internally, by the nasal process of the superior
maxillary, and the internal angular processes of the frontal bone. On the outer
side of the orbit, is the quadrilateral anterior surface of the malar bone, perfora-
ted by one or two small malar foramina. Below the inferior margin of the orbit,
is the infraorbital foramen, the termination of the infraorbital canal, and beneath
this, the canine fossa, which gives attachment to the Levator anguli oris ;
bounded below by the alveolar processes, containing the teeth of the upper and
lower jaw. Beneath the alveolar arch of the lower jaw is the mental foramen
for the passage of the mental nerve and artery, the external oblique line, and at
the lower border of the bone, at the point of junction of the body with the ramus,
a shallow groove for the passage of the facial artery.
The O-rbtts.
The Orbits (Fig. 158) are two quadrilateral pj^ramidal cavities, situated at the
up|Der and anterior part of the face, their bases being directed forwards and out-
wards and their apices backwards and inwards. Each orbit is formed of seve7i
bones, the frontal, sphenoid, ethmoid, superior maxillary, malar, lachrymal, and
palate; but three of these, the frontal, ethmoid, and sphenoid, enter into the for-
mation of both orbits, so that the two cavities are formed of eleven bones only.
Bach cavity presents for examination a roof, a floor, an inner and an outer wall,
four angles, a circumference or base, and an apex. The Roof is concave, directed
downwards and forwards, and formed in front by the orbital plate of the frontal;
behind by the lesser wing of the sphenoid. This surface presents internally the
depression for the fibro-car1ilaginous pulley of the Superior oblique muscle;
externally, tlie depression for the lachrymal gland; and posteriori}', the suture
connecting the frontal and lesser wing of the sphenoid.
The Floor is nearly flat, and of less extent than the roof; it is formed chiefly
by the orbital surface of the superior maxillary ; in front, to a small extent, by
the orbital process of the malar, and behind, by tlie orbital surface of the palate.
This surface presents at its anterior and internal part, just external to the lachry-
mal canal, a depression for the attachment of the Inferior oblique muscle; exter-
nally, the suture between the malar and superior maxillary bones; near its
middle, the infra-orbital groove; and posteriorly, the suture between the maxil-
lary and palate bones.
Tlic Inner Wall is flattened, and formed from before backwards by the nasfd
])roccss of the superior maxillary, the lachrymal, os ]:)la]uim of the ethmoid, and
a small part of the b(jdy of the sphenoid. 'J^'liis surface presents the lachrymal
groove, and crest of the lachrymal bone, and the sutures connecting the ethmoid
with the lachrymal bone in front and the sphenoid behind.
T!ie Outer \Vall is lurmcd in fruut by the orbital process of the malar bone;
NASAL FOSS^. 203
behind by the orbital plate of the sphenoid. On it are seen the orifices of one or
two malar canals, and the suture connecting the sphenoid and malar bones.
Angles. The superior external angle is formed by the junction of the upper
and outer walls , it presents, from before backwards, the suture connecting the
frontal with the malar in front, and with the orbital plate of the sphenoid behind ;
quite posteriorly is the foramen lacerum anterius, or sphenoidal fissure, which
transmits the third, fourth, the ophthalmic division of the fifth and the sixth
nerves, and .the ophthalmic vein. The suijerior internal angle is formed by the
junction of the upper and inner wall, and presents the suture connecting the
frontal bone with the lachrymal in front, and with the ethmoid behind. This
suture is perforated by two foramina, the anterior and posterior ethmoidal, the
former transmitting the anterior ethmoidal artery and nasal nerve, the latter the
posterior ethmoidal artery and vein. The inferior external angle^ formed by the
j unction of the outer wall and floor, presents the spheno-maxillary fissure, which
transmits the infraorbital vessels and nerve, and the ascending branches from
the spheno-palatine ganglion. The inferior internal angle is formed by the union
of the lachrymal and os planum of the ethmoid, with the superior maxillary and
palate bones. The circumference^ or base, of the orbit, quadrilateral in form, is
bounded above by the supraorbital arch ; below, by the anterior border of the
orbital plate of the malar, superior maxillary, and lachrymal bones ; externally
by the internal angular process of the frontal, and the nasal process of the superior
maxillary. The circumference is marked by three sutures, the fronto- maxillary
internally, the fronto-malar externally, and the malo-maxillary below ; it con-
tributes to the formation of the lachrymal groove, and presents above the supra-
orbital notch (or foramen), for the passage of the supra- orbital artery, veins, and
nerve. The apex^ situated at the back of the orbit, corresponds to the optic
foramen, a short circular canal, which transmits the optic nerve and ophthalmic
arterj^. It will thus be seen that there are nine openings communicating with
each orbit, viz. the optic, foramen lacerum anterius, spheno-maxillary fissure,
supraorbital foramen, infraorbital canal, anterior and posterior ethmoidal fora-
mina, and lachrymal canal. To these may be added the external orbital fora-
mina, when present.
The ISTasal Fossje.
The Nasal Fossae are two large irregular cavities, situated in the middle line
of the face, extending from the base of the cranium to the roof of the mouth, and
separated from each other by a thin vertical septum. They comniLinicate by two
large apertures, the anterior nares, with the front of the face ; and with the pha-
rynx behind by the two posterior nares. These foss« are much narrower above
than below, and in the middle than at the anterior or posterior openings : their
depth, which is considerable, is much greater in the middle than at either ex-
tremity. Each nasal fossa communicates with four sinuses, the frontal above,
the sj)lienoidal behind, and the maxillary and ethmoidal on either side. Each
fossa also communicates with four cavities: with the orbit by the lachrymal canal,
with the mouth by the anterior palatine canal, with the cranium by the olfactory
foramina, and with the spheno-maxillary fossa by the spheno-palatine foramen ;
and they occasionally communicate with each other by an aperture in the septum.
The bones entering into their formation are fourteen in number : three of the
cranium, the frontal, sphenoid, and ethmoid, and all the bones of the face, except-
ing the malar and lower jaw. Each cavity is bounded by a roof, a floor, an inner
and an outer wall.
The uf-per tuall^ or roof (Fig. 159), is long, narrow, and concave from before
backwards; it is formed in front by the nasal bones and nasal spine of the frontal,
which are directed downwards and forwards; in the middle, by the cribriform
lamella of the ethmoid, which is horizontal ; and behind, by the under surface of
the body of the sphenoid, and sphenoidal turbinated bones, which are directed
204
THE SKELETON.
downwards and backwards. This surface presents, from before backwards, tlie in-
ternal aspect of the nasal bones ; on their outer side, the suture formed between the
nasal bone and the nasal process of the superior maxillary ; on their inner side,
the elevated crest which receives the nasal spine of the frontal, and the perpen-
Fig. 159. — Roof, Floor, and Outer Wall of Nasal Fossa.
Eoaf
Wn^nl Slj>iru> of FTcntalBone^
Prole pissed thrjiuj-'i'
"Saso -lachrymal Canal
Brzstlc vassedthroiifjh
irJLcndiiiilu-'n'i
OaUr Wall
\asal Ftol: cffSa^Max
Uncifor-mri-oc cf ditto
Inf trior Turhiujui
Palate,
Sujjcrior Meatus
Middle Meatus
Inferior Mcatur
Floor
Avt.Ncbschl SjJiTie
palate rroc.of SufAIax — -
FalaU Troc. of Falatc
Post. Nasal S-pim
Ant. Palatine Canal
dicular plate of the ethmoid, and articulates with its fellow of the opposite side ;
whilst the surface of the bones is perforated by a few small vascular apertures,
and presents the longitudinal groove for the nasal nerve : further back is the
transverse suture, connecting the frontal with the nasal in front, and the ethmoid
behind, the olfactory foramina and nasal slit on the under surface of the cribri-
form plate, and the suture between it and the sphenoid behind : quite posteriorly
are seen the sphenoidal turbinated bones, the orifices of the sphenoidal sinuses,
and the articulation of the al^ of the vomer with the under surface of the body
of the sphenoid.
The floor is flattened from before backwards, concave from side to side, and
wider in the middle than at either extremity. It is formed in front by the
])a]ate process of the superior maxillary; behind, by the palate process of the
palate bone. This surface presents, from before backwards, the anterior nasal
spine ; belli nd this, the upper orifice of the anterior palatine canal ; internally,
the elevated crest which articulates with the vomer ; and behind, the suture
between the palate and superior maxillary bones, and the ]-)csterior nasal spine.
Tlic inner wall^ or septum (Fig. 160), is a thin vertical partition, whicli sepa-
rates the nasal fossa; from one another; it is occasionally ])orforatcd, so that the
fossas communicate, and it is frerprently deflected considerably to one side. It
is formed, in front, by the crest of the nasal bones and nasal spine of the frontal ;
in the middle, by the perpendicular lamella of the ethmoid ; behind, by the
vomer and rostrum of the sphenoid ; below, by the crest of the superior maxil-
lary and palalc bones. It presents, in front, a hirgc triangular notch, which
NASAL FOSS^.
205
receives the triangular cartilage of the nose ; above, the lower orifices of the
olfactory canal; and behind, the guttural edge of the vomer. Its surface is
marked by numerous vascular and nervous canals and the groove for the naso-
palatine nerve, and is traversed by sutures connecting the bones of which it is
formed.
Fig. 160. — Inner Wall of Nasal Fossa, or Septum of Nose.
Crest of Ifasal lont.
Nasal Sjiivs, cj Frontal B.-
Space for Tr2a7iguhi r
CoTtila^e of Septum
, \ ^'^^^ ^ "f Pa ia if. Bonn
'I Cfest of Sap Maxill.Bo7.
The outer zvaJl (Fig. 159) is formed, in front, by the nasal process of the supe-
rior maxillary and lachrymal bones ; in the middle, by the ethmoid and inner
surface of the superior maxillary and inferior turbinated bones ; behind, by the
vertical plate of the palate bone, and the internal pterygoid plate of the sphe-
noid. This surface presents three irregular longitudinal passages, or meatuses,
formed between three horizontal plates of bone that spring from it ; they are
termed the superior, middle, and inferior meatuses of the nose. The superior
meatus^ the smallest of the three, is situated at the upper and back part of each
nasal fossa, occupying the posterior third of the outer wall. It is situated
between the superior and middle turbinated bones, and has opening into it two
foramina, the spheno-palatine at the back of its outer wall, the posterior eth-
moidal cells at the front part of the upper wall. The opening of the sphenoidal
sinuses is usually at the upper and back part of the nasal fossge, immediately
behind the superior turbinated bone. The middle meatus is situated between
the middle and inferior turbinated bones, and occupies the posterior two-thirds
of the outer wall of the nasal fossa. It presents two apertures. In front is the
orifice of the infundibulum, by which the middle meatus communicates with the
anterior ethmoidal cells, and through these with the frontal sinuses. At the
centre of the outer wall is the orifice of the antrum, which varies somewhat as
to its exact position in different skulls. The inferior meatus^ the largest of the
three, is the space between the inferior turbinated bone and the floor of the
nasal fossa. It extends along the entire length of the outer wall of the nose,
is broader in front than behind, and presents anteriorly the lower orifice of the
lachrymal canaL
206
THE SKELETON.
ro-Hyoid
Hyoid
Genio-Hyoid Stcrno-Hyoid
Omo-Hyoid
Mylo-Hyoid
Os Hyoides.
The Hjoid Bone is named from its resemblance to the Greek Upsilon ; it is
also called the Ungual hone^ because it supports the tongue, and gives attach-
ment to its numerous muscles. It is a bony arch, shaped like a horse-shoe, and
consisting of five segments, a body, two greater cornua, and two lesser cornua.
The Body forms the central part of the bone, and is of a quadrilateral form :
its anterior surface (Fig. 161), convex, directed forwards and upw^ards, is divided
into two parts by a vertical
Fig. 161.— Hjoid Bone. Anterior Surface (enlarged), ridge, which descends along the
median line, and is crossed at
right angles by a horizontal ridge,
so that this surface is divided
into four muscular depressions.
At the point of meeting of these
two lines is a prominent eleva-
tion, the tubercle. The portion
above the horizontal ridge is
directed upwards, and is some-
times described as the superior
border. The anterior surface
gives attachment to the Genio-
hyoid in the greater part of its
extent ; above, to the Genio-
hyo-glossus ; below, to the Mylo-
hyoid, Stylo-hyoid, and aponeurosis of the Digastric (supra-hyoid aponeurosis) ,
and between these to part of the Hyo-glossus. The 'posterior surface is smooth,
concave, directed backwards and downwards, and separated from the epiglottis
by the thyro-hyoid membrane, and by a quantity of loose areolar tissue. The
suijerior border is rounded, and gives attachment to the thyro-hyoid membrane,
and part of the Genio-hyo-glossi muscles. The inferior border gives attachment,
in front, to the Sterno-hyoid ; behind, to part of the Thyro-hyoid, and to the
Omo-hyoid at its junction with the great cornu. The lateral surfaces are small,
oval, convex facets, covered with cartilage for articulation with the greater
cornua.
The Greater Cornua project backwards from the lateral surfaces of the body ;
they are flattened from above downwards, diminish in size from before back-
wards, and terminate posteriorly in a tubercle for the attachment of the thyro-
hyoid ligament. Their outer surface gives attachment to the Hyo-glossus ; their
upper border, to the Middle constrictor of the pharynx ; their lower border, to
part of the Thyro-hyoid muscle.
The Lesser Cornua are two small conical-shaped eminences, attached by their
bases to the angles of junction between the body and greater cornua, and giving
attachment by tlieir apices to the stylo-hyoid ligaments. In youth, the cornua are
connected to the body by cartilaginous surfaces, and held together by ligaments ;
in middle life, the body and greater cornua usually become joined ; and in old
age, all the segments are united together, forming a single bone.
Development. By five centres : one for the body, and one for each cornu.
Ossification commences in the body and greater cornua towards the end of foetal
life, those of the cornua first ajjpearing. Ossification of the lesser cornua com-
mences some months after birth.
Attachment of Muscles. Sterno-hyoid, Thyro-hyoid, Omo-hyoid, aponeurosis
of the Digastricus, Stylo-hyoid, Mylo-hyoid, Gcnio-hyoid, Gcnio-hyo-glossus,
Hyo-glossus, Middle constrictor of the pharynx, and occasionally a few fibres of
the Lingualis. It also gives attachiiieut to the thyro-hyoidcan mcnibrano and
the stylo-hyoid, thyro-liyoid, and hyo-cpiglottic ligaments.
STERNUM. 207
THE THOEAX.
The Thorax, or chest, is an osseo-cartilaginous cage, intended to contain and
protect the principal organs of respiration and circulation. It is the second in
size of the three cavities connected with the spine, and is formed by the sternum
and' costal cartilages in front, the twelve ribs on each side, and the bodies of the
dorsal vertebrte behind.
The Sternum.
The Sternum (Figs. 162, 163) is a flat narrow bone, situated in the median
line of the front of the chest, and consisting, in the adult, of three portions. It
has been likened to an ancient sword : the upper piece, representing the handle,
is termed the manubrium ; the middle and largest piece, which represents the
chief part of the blade, is termed the gladiolus ; and the inferior piece, which is
likened to the point of the sword, is termed the ensiform or xiphoid appendix.
In its natural position, its inclination is oblique from above, downwards, and
forwards. It is flattened in front, concave behind, broad above, becoming nar-
rowed at the point where the first and second pieces are connected ; after which
it again widens a little, and is pointed at its extremity. Its average length in
the adult is six inches, being rather longer in the male than in the female.
The First Piece of the sternum, or manuhriion^ is of a somewhat triangular
form, broad and thick above, narrow below at its junction with the middle piece.
Its anterior surface^ convex from side to side, concave from above downwards, is
smooth, and affords attachment on each side to the Pectoralis major and sternal
origin of the Sterno-cleido-mastoid muscle. In well-marked bones, the ridges
limiting the attachment of these muscles are very distinct. Its posterior surface^
concave and smooth, affords attachment on each side to the Sterno-hyoid and
Sterno-thyroid muscles. The superior border^ the thickest, presents at its centre
the interclavicular notch ; and on each side, an oval articular surface, directed
upwards, backwards, and outwards, for articulation with the sternal end of the
clavicle. The inferior border presents an oval rough surface, covered in the re-
cent state with a thin layer of cartilage, for articulation with the second portion
of the bone.-^ The lateral borders are marked above by an articular depression
for the first costal cartilage, and below by a small facet, which, with a similar
facet on the upper angle of the middle portion of the bone, forms a notch for
the reception of the costal cartilage of the second rib. These articular surfaces
are separated by a narrow curved edge, which slopes from above downwards
and inwards.
The Second Piece of the sternum, or gladiolus^ considerably longer, narrower,
and thinner than the first piece, is broader below than above. Its anterior sur-
face is nearly flat, directed upwards and forwards, and marked by three trans-
verse lines which cross the bone opposite the third, fourth, and fifth articular
depressions. These lines are produced by the union of the four separate pieces
of which this part of the bone consists at an early period of life. At the junction
of the third and fourth pieces, is occasionally seen an orifice, the external fora-
1 The second piece of the sternum is united to the first either by an amphiarthrodial joint — a
sinscle piece of true fibro-cartilage uniting the segments — or by a diarthrodial joint, in which each
bone is clothed with a distinct lamina of cartilage, adherent on one side, free and lined with syno-
vial membrane on the other. In the latter case, the cartilage covering the gladiolus is con-
tinued without interruption on to the cartilages of the second ribs. Mr. Rivington has found the
diarthrodial form of joint in about one third of the specimens examined by him. M. Maisonneuve
more frequently. It appears to be rare in childhood, and is formed, in Mr. Rivington's opinion,
from the amphiarthrodial form, by absorption. 'I'he diarthrodial Joint seems to have no ten-
dency to ossify at any age, while the amphiarthrodial is very liable to do so, and has been found
ossified as early as thirty-four years of age. (See Rivington iu " Med. Chir. 'J'raus.," vol. Ivii.)
208
THE SKELETON,
Fig. 162. — Sternum and Costal Cartilages.
SIERNO-CLEIDO. M/(ST0n3 ^^
CLAVIUS \ '%5^ , a(? ^
Fijr. 1G3.- Posterior Surface ol Stcr:;uni.
STERNUM. 209
men; it varies in size and form in different individuals, and pierces the bone
from before backwards. This surface affords attachment on each side to the
sternal origin of the Pectoralis major. The j^osterior surface^ slightly concave, is
also marked by three transverse lines ; but they are less distinct than those in
front: this surface affords attachment below, on each side, to the Triangularis
sterni mnscle, and occasionally presents the posterior opening of the sternal
foramen. The superior border presents an oval surface for articulation with the
manubrium. The inferior harder is narrow and articulates with the ensiform
appendix. Each lateral border presents at each superior angle a small facet,
which, with a similar facet on the manubrium, forms a cavity for the cartilage
of the second rib ; the four succeeding angular depressions receive the cartilages
of the third, fourth, fifth, and sixth ribs, whilst each inferior angle presents a
small facet, which with a corresponding one on the ensiform appendix, forms a
notch for the cartilage of the seventh rib. These articular depressions are sepa-
rated by a series of curved interarticular intervals, which diminish in length
from above downwards, and correspond to the intercostal spaces. Most of the
cartilages belonging to the true ribs, as will be seen from the foregoing descrip-
tion, articulate with the sterum at the line of junction of two of its primitive
component segments. This is well seen in many of the lower animals, where
the separate parts of the bone remain ununited longer than in man. In this
respect a striking analogy exists between the mode of connection of the ribs
with the vertebral column, and the connection of their cartilages with the
sternal column.
The Third piece of the sternum, the ensiform, or xiphoid appendix^ is the
smallest of the three ; it is thin and elongated in form, cartilaginous in structure
in youth, but more or less ossified at its upper part in the adult. Its anterior
surface affords attachment to the costo"- xiphoid ligaments ; its posterior surface^
to some of the fibres of the Diaphragm and Triangularis sterni muscles : its lateral
borders^ to the aponeurosis of the abdominal muscles. Above, it is continuous
with the lower end of the gladiolus ; below, by its pointed extremity, it gives
attachment to the linea alba, and at each superior angle presents a facet for the
lower half of the cartilage of the seventh rib. This portion of the sternum is
very various in appearance, being sometimes pointed, broad and thin, sometimes
bifid, or perforated by a round hole, occasionally curved, or deflected considera-
bly to one or the other side.
Structure. The bone is composed of delicate cancellated texture, covered by
a thin layer of compact tissue, which is thickest in the manubrium, between
the articular facets for the clavicles.
Development. The sternum, including the ensiform appendix, is developed
by six centres : one for the first piece or manubrium, four for the second piece
or gladiolus, and one for the ensiform appendix. Up to the middle of foetal life,
the sternum is entirely cartilaginous, and when ossification takes place, the
ossific granules are deposited in the middle of the intervals between the articu-
lar depressions for the costal cartilages, in the following order (Fig. 164). In
the first piece, between the fifth and sixth months ; in the second and third,
between the sixth and seventh months; in the fourth piece, at the ninth month;
in the fifth, within the first year, or between the first and second years after
birth ; and in the ensiform appendix, between the second and the seventeenth
or eighteenth years, by a single centre which makes its appearance at the upper
part, and proceeds gradually downwards. To these may be added the occasional
existence, as described by Breschet, of two small episternal centres, which make
their appearance one on each side of the interclavicular notch. These are
regarded by him as the anterior rudiments of a rib, of which the posterior rudi-
ment is the anterior lamina of the transverse process of the seventh cervical
vertebra. It occasionally happens that some of the segments are formed from
more than one centre, the number and position of which vary (Fig. 166). Thus
the first piece may have two, three, or even six centres. When two are present.
210
THE SKELETON.
Fig. 164. — Development of the Sternum, by Six Centres.
<:
m^
rj i fori^ piece ^S'&TPM.fatal
or Koi'iui^rLwrn
3@ [
1(5-7 »"^-
— ' GltvoUolus
:3
5. If^y.'^afuj
^birk
'^cit!i7o'v^-'»'-^---
^Plg. Itio.
Tiumh&T of
C cntres
except Cncli^oqa
3S-l,0.
Z0-23fh Tjuti
>™„™™,„^v\ ( i 0071 after pahcrtjf
S r
jmrtly cariiZa^i/wus in.
advanr^ed life
Fig. 166. — Peculiarities.
far 1'f jjvece Zc^r tnore reTTtrcs
Z'i^ puce,iosiui7lTf one
A- vf \ 2 placed latiraiUij
cth.
And in
Mode of
Union,
Fig. 167.
%-^ Arrrst of Dei^^lopmejit
of laterail vicecs producinof
Stenuil fissare k
SteriLol fora incn
they are generally situated
one above tlie other, the
upper one being the larger;
the second piece has seldom
more than one; the third,
fourth, and fifth pieces are
often formed from two cen-
tres placed laterally, the
irregular union of which will
serve to explain the occa-
sional occurrence of the ster-
nal foramen (Fig. 167), or of
the vertical fissure which
occasionally intersects this
part of the bone. Union of
the various centres com-
mences from below, and pro-
ceeds upwards, taking place
in the following order (Fig.
165). The fifth piece is
joined to the fourth soon
after puberty; the fourth to
the third, between the twen-
tieth and twenty -fifth years ;
the third to the second,
between the thirty -fifth and
fortieth years ; the second is
occasionally joined to the
first, especially at an ad-
vanced age
Articulations. With the
clavicles, and seven costal
cartilages on each side.
Attachment of Muscles.
The Pectoralis major, Sterno-
cleido-mastoid, Sterno-hyoid,
Sterno-thyroid, Triangularis
sterni, aponeurosis of the
Obliquus externus, Obliquus
internus, and Transversalis
muscles, Eectus and Dia-
phragm.
The Eibs.
The Eibs are elastic
arches of bone, which form
the chief part of the thoracic
walls. They are twelve in
number on each side; but
this number may be increased
by the dovclo])mcnt of a cer-
vical or lumbar rib, or may
be diminished to eleven.
Tlie first seven are connect-
ed beliind with the spine,
and in front with the ster-
EIBS.
211
Fig.
num, tlirougli the intervention of tlie costal cartilages;
sternal^ or true ribs. The remaining five are false ribs
being connected behind with the spine, and in
front with the costal cartilages, are usually called
the vertebro-costal, but would be better named the
vertebro-chondral ribs : the last two are connected
with the vertebra3 only, being free at their anterior
extremities; they are termed vertebral or floating
'ribs. The ribs vary in their direction, the upper
ones being placed nearly at right angles with the
spine, the lower ones obliquely, so that the ante-
rior extremity is lower tlian the posterior. The
extent of obliquity reaches its maximum at the
ninth rib, and gradually decreases from that rib
to the twelfth. The ribs are situated one below
the other in such a manner that spaces are left
between them, which are called iiitercostal spaces.
Their length corresponds to the length of the ribs,
their breadth is more considerable in front than
behind, and between the upper than between the
lower ribs. The ribs" increase in length from the
first to the seventh, when they again diminish to
the twelfth. In breadth they decrease from above
downwards; in each rib the greatest breadth is
at the sternal extremity.
Common characters of the Ribs (Fig. 168). A rib
from the middle of the series should be taken in
order to study the common characters of the ribs.
Each rib presents two extremities, a posterior
or vertebral, an anterior or sternal, and an inter-
vening portion, the body or shaft. The posterior
or vertebral extremity presents for examination a
head, neck, and tuberosity. The head (Fig. 169)
is marked by a kidney-shaped articular surface,
divided by a horizontal ridge into two facets for
articulation with the costal cavity formed by the
junction of the bodies of two contiguous dorsal
vertebrae; the upper facet is small, the inferior
one of large size ; the ridge separating them serves
for the attachment of the interarticular ligament.
The nech is that flattened portion of the rib
which extends outwards from the head ; it is about
an inch long, and rests upon the transverse process
of the lower of the two vertebrae with which the
head articulates. Its anterior surface is flat and
smooth, its posterior rough, for the attachment of
the middle costo- transverse ligament, and perfo-
rated by numerous foramina, the direction of
which is less constant than those found on the
inner surface of the shaft. Of its two borders the
superior presents a rough crest for the attachment
of the anterior costo-transverse ligament ; its infe-
rior border is rounded. On the posterior surface
of the neck, just where it joins the shaft, and
nearer the lower than the upper border, is an
eminence — the tuberosity, or tubercle; it consists
of an articular and a non-articular portion. The
they are called vertebro-
; of these the first three,
168.— A Central Rib of Right
Side. Inner Surface.
^
'^
c; 2i|!
212
"THE SKELETON.
articular portion^ the more internal and inferior of tlie two, presents a small oval
surface for articulation witli the extremity of the transverse process of the lower
of the two vertebras to which the head is connected. The non- articular portion
is a rough elevation, which affords attachment to the posterior costo-transverse
ligament. The tubercle is much more prominent in the upper than in the
lower ribs.
Fig. 169. — Vertebral Extremity of a Rib. External Surface.
/.T Ant-. CnsJ^-fTai^Ligi far post:: Co,io-iran,verse Li,)i
Facet fur hodii of iup]>e^y Dornal Vortclra^
Jildue for Inte r-artuular Luj--~
Fount for 1/afy of lower Dorsal Vert^^
for tratuv.'proc. of lamer JJoisft''
The sliaft is thin and flat, so as to present two surfaces, an external and an
internal; and two borders, a superior and an inferior. The external surface is
convex, smooth, and marked, at its back part, a little in front of the tuberosity,
by a prominent line, directed obliquely from above, downwards and outwards;
this gives attachment to a tendon of the Sacro-lumbalis muscle, or of one of its
accessory portions, and is called the angle. At this point, the rib is bent in two
directions. If the rib is laid upon its lower border, it will be seen that the
anterior portion of the shaft, as far as the angle, rests upon this margin, while
the vertebral end of the bone, beyond the angle, is bent inwards and at the
same time tilted upwards. The interval between the angle and the tuberosity
increases gradually from the second to the tenth rib. The portion of bone
between these two parts is rounded, rough, and irregular, and serves for the
attachment of the Longissimus dorsi. The portion of bone between the angle
and sternal extremity is also slightly twisted upon its own axis, the external
surface looking downwards behind the angle, a little upwards in front of it. This
surface presents, towards its sternal extremity, an oblique line, the anterior angle.
The internal surface is concave, smooth, directed a little upwards behind the
angle ; a little downwards in front of it. This surface is marked by a ridge
which commences at the lower extremity of the head ; it is strongly marked as
far as the inner side of the angle, and gradually becomes lost at the junction of
the anterior with the middle third of the bone. The interval between it and
the inferior border is deeply grooved, to lodge the intercostal vessels and nerve.
At the back part of the bone, this groove belongs to the inferior border, but just
in front of the angle, where it is deepest and broadest, it corresponds to the
internal surface. The superior edge of the groove is rounded ; it serves for the
attachment of the Internal intercostal muscle. The inferior edge corresponds
to the lower margin of the rib, and gives attachment to the External intercostal.
Within the groove are seen the orifices of numerous small foramina, Avhich
traverse the wall of the shaft obliquely from before backwards. The superior
harder^ thick and rounded, is marked by an external and an internal lip, more
distinct behind than in front; they serve for the attachment of the External and
Internal intercostal muscles. The inferior border^ thin and sharp, has attached
the External intercostal muscle. The anterior or sternal extremity is flattened,
and presents a porous oval concave depression, into which the costal cartilage is
received.
Peculiae Eibs.
The ribs which require especial consideration are five in number, viz., the
first, second, tenth, eleventli, and twelftli.
They?r.s7 rih (Fig. 170) is one of the shortest and the most curved of all the
RIBS.
213
ribs ; it is broad, flat, and placed horizontally at the upper part of the thorax,
its surfaces looking upwards and downwards ; and its borders inwards and out-
wards. The head is of small size, rounded, and presents only a single articular
facet for articulation with the body of the first dorsal vertebra. The neck is
narrow and rounded. The tuberosity^ thick and prominent, rests on the outer
border. There is no angle, and the shaft is not twisted on its axis. The upper
Peculiar Ribs.
Fig. 171
.Any I I
Slif^Mi/ mark
Jii^elosc to tiller osi
pjuu^
hnjn^"
Fig. 172.
Fiff. 173.
Silngh (IT lie- fa-eet-
Fiff. 174.
JwJjr/* artic. fac.
surface of the shaft is marked by two shallow depressions, separated from one
another by a ridge which becomes more prominent towards the internal border,
where it terminates in a tubercle : this tubercle and ridge serve for the attach-
ment of the Scalenus anticus muscle, the groove in front of it transmitting the sub-
214 THE SKELETON.
clavian vein : that beMnd it, the subclavian artery. Between the groove for the
subclavian artery and the tuberosity is a depression for the attachment of the Sca-
lenus medius muscle. The under surface is smooth, and destitute of the groove
observed on the other ribs. The outer border is convex, thick, and rounded ; the
inner, concave, thin, and sharp, and marked about its centre by the tubercle
before mentioned. The anterior extremity is larger and thicker than any of the
other ribs.
The second rib (Fig. 171) is much longer than the first, but bears a very con-
siderable resemblance to it in the direction of its curvature. The non-articular
portion of the tuberosity is occasionally only slightly marked. The angle is
slight, and situated close to the tuberosity, and the shaft is not twisted, so that
both ends touch any plane surface upon which it may be laid. The shaft is not
horizontal, like that of the first rib ; its outer surface, which is convex, looking
upwards and a little outwards. It presents, near the middle, a rough eminence
for the attachment of the second and third digitations of the Serratus magnus.
The inner surf ace, smooth and concave, is directed downwards and a little inwards :
it presents a short groove towards its posterior part.
The tenth rib (Fig. 172) has only a single articular facet on its head.
The eleventh and twelfth ribs (Figs. 173 and 174) have each a single articular
facet on the head, which is of rather large size ; they have no neck or tuberosity,
and are pointed at the extremity. The eleventh has a slight angle and a shallow
groove on the lower border. The twelfth has neither, and is much shorter than
the eleventh.
Structure. The ribs consist of cancellous tissue, enclosed in a thin compact
layer.
Development. Each rib, with the exception of the last two, is developed by
three centres : one for the shaft, one for the head, and one for the tubercle. The
last two have only two centres, that for the tubercle being wanting. Ossification
commences in the body of the ribs at a very early period, before its appearance
in the vertebrae. The epiphysis of the head, which is of a slightly angular shape,
and that for the tubercle, of a lenticular form, make their appearance between
the sixteenth and twentieth years, and are not united to the rest of the bone until
about the twenty-fifth year.
Attachment of Muscles. The Intercostals, Scalenus anticus. Scalenus medius.
Scalenus posticus, Pectoralis minor, Serratus magnus, Obliquus externus, Trans-
versalis, Qnadratas lumborum. Diaphragm, Latissimus dorsi, Serratus posticus
superior, Serratus posticus inferior, Sacro-lumbalis, Musculus accessorius ad sacro-
lumbalem, Longissimus dorsi, Ccrvicalis ascendens, Levatores costarum.
The Costal Caetilages.
The Costal Cartilages (Fig. 162, p. 208) are white elastic structures, which serve
to prolong the ribs forward to the front of the chest, and contribute very materially
to the elasticity of its walls. The first seven are connected with the sternum,
the next three with the lower border of the cartilage of the preceding rib. The
cartilages of the last two ribs, which have pointed extremities, float freely in the
walls of the abdomen. Like the ribs, the costal cartilages vary in their length,
breadth, and direction. They increase in length from the first to the seventh,
then gradually diminish to the last. They diminish in breadth, as well as the
intervals between them, from the first to the last. They are broad at their
attachfncnt to the ribs, and taper towards their sternal extremities, excepting
the first two, which arc of the same length throughout, and the sixth, seventh, and
eighth, which are enlarged where their margins arc in contact. In direction
they also vary; the first descends a little, the second is horizontal, the third
ascends slightly, whilst all the rest follow the course of the ribs for a short extent,
and then ascend to the sternum or preceding cartilage. Kach costal cartilage
presents two surfaces, two borders, and two extremities. The anterior surface
THE UPPER EXTREMITY. 215
is convex, and looks forwards, and upwards ; tliat of the first gives attacTiment
to tlie costo-clavicular ligament ; that of the first, second, third, fourth, fifth, and
sixth, at their sternal ends, to the Pectoralis major. The others are covered by,
and give partial attachment to, some of th€ great flat muscles of the abdomen.
The 'posterior surface is concave, and directed backwards and downwards, the six
or seven inferior ones aifording attachment to the Transversalis muscle, and the
Diaphragm. Of the two borders, the superior is concave ; the inferior, convex ;
they afibrd attachment to the Intercostal muscles, the upper border of the sixth
giving attachment to the Pectoralis major muscle. The contiguous borders of
the sixth, seventh, and eighth, and sometimes the ninth and tenth, costal cartilages
present smooth oblong surfaces at the points where they articulate. Of the two
extremities, the outer one is continuous with the osseous tissue of the rib to
which it belongs. The inner extremity of the first is continuous with the sternum ;
the six succeeding ones have rounded extremities, which are received into
shallow concavities on the lateral margins of the sternum. The inner extremi-
ties of the eighth, ninth, and tenth costal cartilages are pointed, and lie in contact
with the cartilage above. Those of the eleventh and twelfth are free and pointed.
The costal cartilages are most elastic in youth, those of the false ribs being
more so than the true. In old age, they become of a deep yellow color. Under
certain diseased conditions, they are prone to ossify. Dr. Humphry's observa-
tions on this subject have led him to regard the ossification of the costal carti-
lages as a sign of disease rather than of age. " The ossification takes place in
the first cartilage sooner than in the others ; and in men more frequently, and
at an earlier period of life, than in women."
Attachment of Muscles. The Subclavius, Sterno-thyroid, Pectoralis major,
Internal oblique, Transversalis, Eectus, Diaphragm, Triangularis sterni. Internal
and External intercostals.
OF THE EXTREMITIES.
The Extremities, or limbs, are those long jointed appendages of the body,
which are connected to the trunk by one end, and free in the rest of their extent.
They are four in number : an upper or thoracic pair^ connected with the thorax
through the intervention of the shoulder, and subservient mainly to tact and
prehension ; and a lotoer pair^ connected with the pelvis, intended for support
and locomotion. Both pairs of limbs are constructed after one common type,
so that they present numerous analogies ; while at the same time certain differ-
ences are observed in each, dependent on the peculiar offices they perform.
Of the Upper Extremity.
The Upper Extremity consists of the arm, the forearm, and the hand. Its
continuity with the trunk is established by means of the shoulder, which is
homologous with the innominate or haunch bone in the lower limb.
Of the Shoulder.
The Shoulder is placed upon the upper part and side of the chest, connecting
the upper extremity to the trunk ; it consists of two bones — the clavicle, and
the scapula.
The Clavicle.
The Clavicle {clavis^ a key), or collar-bone, forms the anterior portion of the
shoulder. It is a long bone, curved somewhat like the italic letter/, and placed
nearly horizontally at the upper and anterior part of the thorax, immediately
above the first rib. It articulates by its inner extremity with the up]3er border
216 THE SKELETON.
of tlie sternum, and, by its outer extremity, witli the acromion process of the
scapula ; serving to sustain the upper extremity in the various positions which
it assumes, whilst, at the same time, it allows of great latitude of motion in the
arm. The clavicle is nearly horizontal. It presents a double curvature, when
looked at in front ; the convexity being forwards at the sternal end, and the
concavity at the scapular end. Its outer third is flattened from above down-
wards, arid extends, in the natural position of the bone, from a point opposite
the coracoid process to the acromion. Its inner two-thirds are of a cylindrical
form, and extend from the sternum to a point opposite the coracoid process of
the scapula.
External or Flattened Portion. The outer third is flattened from above down-
wards, so as to present two surfaces, an upper and a lower ; and two borders,
an anterior and a posterior. The upper surface is flattened, rough, marked by
impressions for the attachment of the Deltoid in front, and the Trapezius behind :
between these two impressions, externally, a small portion of the bone is sub-
cutaneous. The under surface is flattened. At its posterior border, where the
prismatic joins with the flattened portion, is a rough eminence, the conoid
tuhercle ; this, in the natural position of the bone, surmounts the coracoid pro-
cess of the scapula, and gives attachment to the conoid ligament. From this
tubercle, an oblique line, occasionally a depression, passes forwards and outwards
to near the outer end of the anterior border ; it is called the oblique line^. and
affords attachment to the trapezoid ligament. The anterior harder is concave,
thin, and rough ; it limits the attachment of the Deltoid, and occasionally pre-
sents, near the centre, a tubercle, the deltoid tuhercle^ which is sometimes distinct
in the living subject. ^\\q posterior border is convex, rough, broader than the
anterior, and gives attachment to the Trapezius.
Internal or Cylindrical Portion. The cylindrical portion forms the inner tioo-
thirds of the bone. It is curved, so as to be convex in front, concave behind,
and is marked by three borders separating three surfaces. The anterior border
is continuous with the anterior margin of the flat portion. At its commence-
ment it is smooth and corresponds to the interval between the attachment of the
Pectoralis major and Deltoid muscles ; about the centre of the clavicle it divides
to inclose an elliptical space for the attachment of the clavicular portion of the
Pectoralis major. This space extends inwards as far as the anterior margin of
the sternal extremity. The superior border is continuous with the posterior
margin of the flat portion, and separates the anterior from the posterior surface.
At its commencement it is smooth and rounded, becomes rough towards the
inner third for the attachment of the Sterno-mastoid muscle, and terminates at
the upper angle of the sternal extremity. The posterior or sid)clavian border
separates the posterior from the inferior surface, and extends from the conoid
tubercle to the rhomboid impression. It forms the posterior boundary of the
groove for the Subclavius muscle, and gives attachment to the fascia which
incloses that muscle. The anterior surface is included between the superior and
anterior borders. It is directed forwards and a little upwards at the sternal end,
outwards and still more upwards at the acromial extremity, where it becomes
continuous with the upper surface of the flat portion. Externally, it is smooth,
convex, nearly subcutaneous, being covered only by the Platysma ; but corre-
sponding to the inner lialf of the bone, it is divided by a more or less promi-
nent line into two parts : an anterior portion, cllipitical in form, rough, and
sliglitly convex, for the attachment of the Pectoralis major ; and an upper part,
which is rough behind, for the attachment of the Sterno-cleido-mastoid. Be-
tween the two muscular impressions is a small subcutaneous interval. Tlie
posterior or cervical surface is smooth, flat, directed vertically, and looks back-
wards towards tlic root of the neck. It is limited, above, by the superior
border; below, by the subclavian border; internally,- by the margin of the
sternal extremity ; externally, it is continuous with the posterior border of the
flat portion. It is concave from witln'n outwards, and is in relation, by its lower
CLAVICLE.
217
part, with the Suprascapular vessels. It gives attachment, near the sternal
extremity, to part of the Sterno-hyoicl muscle ; and presents, at or near the
middle, a foramen, directed obliquely outwards, which transmits the chief
nutrient artery of the bone. Sometimes, there are two foramina on the poste-
rior surface, or one on the posterior, the other on the inferior surface. The
inferior or subclavian surface is bounded, in front, by the anterior border ;
behind, by the subclavian border. It is narrow internally, but gradually
Fiff. 175. — Left Clavicle. Anterior Surface.
Sle TTial -Ea:tTe^dtij
Ap-fumial Uxt.y
Fig. 176.— Left Clavicle. Inferior Surface.
I
increases in width externally, and is continuous with the under surface of the
flat portion. Commencing at the sternal extremity may be seen a small facet
for articulation with the cartilage of the first rib. This is continuous with the
articular surface at the sternal end of the bone. External to this is a broad
rough impression, the rhomboid, rather more than an inch in length, for the
attachment of the costo-clavicular (rhomboid) ligament. The remaining part
of this surface is occupied by a longitudinal groove, the subclavian groove,
broad and smooth externally, narrow and more uneven internally ; it gives
attachment to the subclavius muscle, and, by its anterior margin to the strong
aponeurosis which incloses it. Not unfrequently this groove is subdivided into
two parts by a longitudinal line, which gives attachment to the intermuscular
septum of the subclavius muscle.
The internal or sternal end of the clavicle is triangular in form, directed in-
wards, and a little downwards and forwards; and presents an articular facet,
concave from before backwards, convex from above downwards, which articu-
lates with the sterum through the intervention of an interarticular fibro-carti-
lage; the circumference of the articular surface is rough, for the attachment of
numerous ligaments. This surface is continuous with the costal facet on the
inner end of the inferior or subclavian surface, which articulates with the
cartilage of the first rib.
The outer or acromial extremity^ directed outwards and forwards, presents a
small, flattened, oval facet, which looks obliquely downwards for articulation
with the acromion process of the scapula. The direction of this surface serves
to explain the greater frequency of dislocation upwards rather than downwards,
218 THE SKELETON.
beneath the acromion process. The circumference of the articular facet is rough,
especially above, for the attachment of the acromio-clavicular ligaments.
Peculiarities of the Bone in the Sexes and in Individuals. In the female, the
clavicle is generally less curved, smoother, and more slender than in the male.
In those persons who perform considerable manual labor, which brings into
constant action the muscles connected with this bone, it acquires considerable
bulk, becomes shorter, more curved, its ridges for muscular attachment become
prominently marked, and its sternal end of a prismatic form. The right cla-
vicle is generally heavier, thicker, and rougher, and often shorter, than the
left.
Structure. The shaft, as well as the extremities, consists of cancellous tissue,
invested in a compact layer much thicker in the middle than at either end.
The clavicle is highly elastic, by reason of its curves. From the experiments
of Mr. Ward, it has been shown that it possesses suf&cient longitudinal elastic
force to project its own weight nearly two feet on a level surface, when a smart
blow is struck on it ; and suf&cient transverse elastic force, opposite the centre of
its anterior convexity, to throw its own weight about a foot. This extent of
elastic power must serve to moderate very considerably the efi'ect of concussions
received upon the point of the shoulder.
Development. By two centres : one for the shaft, and one for the sternal ex-
tremity. The centre for the shaft appears very early, before any other bone ;
the centre for the sternal end makes its appearance about the eighteenth or
twentieth year, and unites with the rest of the bone a few years after.
Articulations. With the sternum, scapula, and cartilage of the first rib.
Attachment of Muscles. The Sterno-cleido-mastoid, Trapezius, Pectoralis
major. Deltoid, Subclavius, Sterno-hyoid, and Platysma.
The Scapula.
The Scapula forms the back part of the shoulder. It is a large flat bone,
triangular in shape, situated at the posterior aspect and side of the thorax,
between the first and eighth ribs, its posterior border or base being about an inch
from, and nearly parallel with the spinous processes of the vertebrae. It presents
for examination two surfaces, three borders, and three angles.
The anterior surface, or venter (Fig. 177), presents a broad concavity, the sub-
scapular fossa. It is marked, in the posterior two-thirds, by several oblique
ridges, which pass from behind obliquely outwards and upwards, the anterior
third being smooth. The oblique ridges give attachment to the tendinous inter-
sections, and the surfaces between them, to the fleshy fibres, of the Subscapularis
muscle. The anterior third of the fossa, which is smooth, is covered by, but
does not aff'ord attachment to, the fibres of this muscle. This surface is sepa-
rated from tlie posterior border by a smooth triangular margin at the superior
and inferior angles, and in the interval between these by a narrow edge which is
often deficient. This marginal surface affords attachment throughout its entire
extent to the Serratus magnus muscle. The subscapular fossa presents a trans-
verse depression at its upper part, called the suhscapular anyle ; it is in this
situation that the fossa is deepest ; so that the thickest part of the Subscapularis
muscle lies in a line perpendicular to the plnne of the glenoid cavity, aud must
consequently operate most cfl'ectively on 1 lie humerus which is contained in that
cavity.
T\\e posterior surface^ or dorsum, (Fig. 178), is arched from ai)ove downwards,
alternately concave and convex from side to side. It is subdivided unequally
into two parts by the spine; the portion above the spine is called the supraspi-
nous fossa, and that beloAV it the infrasy)inous fossa.
The siiprasjiinov.s fossa., the smaller of the two, is concave, smoolli, and In'oader
at the verte1)ral than at the humeral extremity. It affords attachment by its
inner two-thirds to the Supraspinatus muscle.
SCAPULA.
219
Tlie infraspinous fossa is mucli larger tlaan the preceding; towards its verte-
bral margin a shallow concavity is seen at its upper part; its centre presents a
prominent convexity, whilst towards the axillary border is a deep groove, which
runs from the upper towards the lower part. The inner two-thirds of this sur-
Fig. 171.— -Left Scapula. Anterior Surface, or Yenter.
face affords attachment to the Infraspinatus muscle; the outer third is only
covered by it, without giving origin to its fibres. This surface is separated from
the axillary border by an elevated ridge, which runs from the lower part of the
glenoid cavity, downwards and backwards to the posterior border, about an inch
above the inferior angle. The ridge serves for the attachment of a strong apo-
neurosis, which separates the Infraspinatus from the two Teres muscles. The
surface of bone between this line and the axillary border is narrow in the upper
two-thirds of its extent, and traversed near its centre by a groove for the passage
of the dorsalis scapulae vessels ; it affords attachment to the Teres minor. Its
lower third presents a broader, somewhat triangular surface, which gives origin
to the Teres major, and over which glides the Latissimus dorsi; sometimes the
220
THE SKELETON.
latter muscle takes origin by a few fibres from tbis part. Tbe broad and nar-
row portions of bone above alluded to are separated bj an oblique line, wbicb
runs from tbe axillary border, downwards and backwards : to it is attached tbe
aponeurosis separating the two Teres muscles from each other.
^es s
Fig. 178. — Left Scapula. Posterior Surface, or Dorsum.
Co racoiei
The ^^'pina is a prominent plate of bone, which crosses obliquely the inner
four-fifths of the dorsum of the scapula at its upper part, and separates the
Bupra- from tlic infra-spinous fossa: it commences at tlie vertebral border by a
smooth triangular surface, over which the Trapezius glides, scpiirated from the
bone by a bursa; and, gradually becoming more elevated as it passes forwards,
terminates in the acromion process which overhangs the shoulder -joint. The
spine is triangular, and flattened from above downwards, its apex corresponding
to the posterior border; its base, which is directed outwards, to the neck of the
.scapula. It presents two surfaces and ihrce borders. Its svperior svrface is
concave assists in foriiiing ihc supra.'^])inons fo.ssa, and alTords attachment to
SCAPULA. 221
part of tlie Supraspinatus muscle. Its inferior surface forms part of tlie infra-
spinous fossa, gives origin to ]3art of tlie Infraspinatus muscle, and presents near
its centre the oritice of a nutrient canal. Of the three borders, the anterior is
attached to the dorsum of the bone ; the posterior^ or crest of the spine, is broad,
and presents two lips, and an intervening rough interval. To the superior lip
is attached the Trapezius, to the extent shown in the figure. A very rough
tubercle is generally seen occupying that portion of the spine which receives the
insertion of the middle and inferior fibres of this muscle. To the inferior lip,
throughout its whole length, is attached the Deltoid. The interval between the
lips is also partly covered by the fibres of these muscles. The external border^
the shortest of the three, is slightly concave, its edges thick and round, continu-
ous above with the under surface of the acromion process ; below, with the neck
of the scapula. The narrow portion of bone external to this border serves to
connect the supra- and infra-spinous fossse.
The Acroonion process^ so called from forming the summit of the shoulder
(axpov, a summit; ^^oj, the shoulder), is a large and somewhat triangular process,
flattened from behind forwards, directed at first a little outwards, and then curv-
ing forwards and upwards, so as to overhang the glenoid cavity. Its upper sur-
face^ directed upwards, backwards, and outwards, is convex, rough, and gives
attachment to some fibres of the Deltoid. Its under surface is smooth and con-
cave. Its outer horder^ which is thick and irregular, affords attachment to the
Deltoid raiuscle. Its inner margin^ shorter than the outer, is concave, gives at-
tachment to a portion of the Trapezius muscle, and presents about its centre a
small oval surface, for articulation with the acromial end of the clavicle. Its
apex^ which corresponds to the point of meeting of these two borders in front, is
thin, and has attached to it the coraco-acromial ligament.
Of the three borders or costse of the scapula, the superior is the shortest and
thinnest ; it is concave, terminating at its inner extremity at the superior angle,
at its outer extremity at the coracoid process. At its outer part is a deep
semicircular notch, the suprascapular, formed partly by the base of the coracoid
process. This notch is converted into a foramen by the transverse ligament, and
serves for the passage of the suprascapular nerve. The adjacent margin of the
superior border affords attachment to the Omo-hyoid muscle. The external^ or
axillary border^ is the thickest of the three. It commences above at the lower
margin of the glenoid cavity, and inclines obliquely downwards and backwards
to the inferior angle. Immediately below the glenoid cavity, is a rough im-
pression, about an inch in length, which affords attachment to the long head of
the Triceps muscle ; to this succeeds a longitudinal groove, which extends as far
as its lower third, and affords origin to part of the Subscapular! s muscle. The
inferior third of this border, which is thin and sharp, serves for the attachment
of a few fibres of the Teres major behind, and of the Subscapularis in front.
The internal^ or vertebral^ border^ also named the base, is the longest of the three,
and extends from the superior to the inferior angle of the bone. It is arched,
intermediate in thickness between the superior and the external borders, and
the portion of it above the spine is bent considerably outwards, so as to form an
obtuse angle with the lower part. The vertebral border presents an anterior
lip, a posterior lip, and an intermediate space. The anterior lip affords attach-
ment to the Serratus magnus ; the posterior lip, to the Supraspinatus above the
spine, the Infraspinatus below ; the interval between the two lips, to the Levator
anguli scapulae above the triangular surface at the commencement of the spine;
the Ehomboideus minor, to the edge of that surface; the Rhomboideus major
being attached by means of a fibrous arch, connected above to the lower part of
the triangular surface at the base of the spine, and below to the lower part of
the posterior border.
Of the three angles, the superior, formed by the junction of the superior and
internal borders, is thin, smooth, rounded, somewhat inclined outwards, and
gives attachment to a few fibres of the Levator anguli scapulae muscle. The
222 THE SKELETON.
■inferior angle, thick and rougli, is formed by tlie union of tlie vertebral and
axillary borders, its outer surface affording attacliment to tbe Teres major, and
occasionally a few fibres of tlie Latissimus dorsi. The anterior angle is the
thickest part of the bone, and forms what is called the head of the scapula. The
head presents a shallow, pyriform, articular surface, the glenoid cavity (yxij^}?, a
socket\ whose longest diameter is from above downwards, and its direction out-
wards and forwards. It is broader below than above : at its apex is attached
the long tendon of the Biceps muscle. It is covered with cartilage in the recent
state ; and its margins, slightly raised, give attachment to a fibro-cartilaginous
structure, the glenoid ligament, by which its cavity is deepened. The neck of
the scapula is the slightly depressed surface which surrounds the head ; it is
more distinct on the posterior than on the anterior surface, and below than
above. In the latter situation, it has, arising from it, a thick prominence, the
coracoid process.
The Coracoid process^ so called from its fancied resemblance to a crow's beak
(xopal, a crow), is a thick curved process of bone, which arises by a broad base
from the upper part of the neck of the scapula ; it is directed at first upwards and
inwards ; then, becoming smaller, it changes its direction, and passes forwards
and outwards. The ascending portion, flattened from before backwards, presents
in front a smooth concave surface, over which passes the Subscapularis muscle.
The horizontal portion is flattened from above downwards ; its upper surface is
convex and irregular ; its under surface is smooth ; its anterior border is rough,
and gives attachment to the Pectoralis minor ; its posterior border is also rough
for the coraco-acromial ligament, while the apex is embraced by the conjoined
tendon of origin of the short head of the Biceps and of the Coraco-brachialis.
At the inner side of the root of the coracoid process is a rough impression for
the attachment of the conoid ligament ; and, running from it obliqiiely forwards
and outwards on the upper surface of the horizontal portion, an elevated ridge
for the attachment of the trapezoid ligament.
/Structure. In the head, processes, and all the thickened parts of the bone, it
is cellular in structure, of a dense compact tissue in the rest of its extent. The
centre and upper part of the dorsum, but especially the former, are usually so
thin as to be semi-transparent; occasionally the bone is found wanting in this
situation, and the adjacent muscles come into contact.
Development (Fig, 179). By seven centres: one for the body, two for the
coracoid process, two for the acromion, one for the posterior border, and one for
the inferior angle.
Ossification of the body of the scapula commences about the second month of
foital life, by the formation of an irregular quadrilateral plate of bone, imme-
diately behind the glenoid cavity. This plate extends itself so as to form the
chief part of the bone, the spine growing up from its posterior surface about the
third month. At birth, the chief part of the scapula is osseous, only the coracoid
and acromion processes, the posterior border, and inferior angle, being carti-
laginous. About the first year after birth, ossification takes place in the middle
of the coracoid process; which usually becomes joined with the rest of the bone
at the time when the other centres make their appearance. Between the fif-
teenth and seventeenth years, ossification of the remaining centres takes place
in quick succession, and in the following order: first, near the base of the
acromion, and in tlie root of the comcoid process, the latter appearing in the
form of a broad Hcale; secondly, in the inferior angle and contiguous part of the
posterior ])ordcr; tliirdly, nc;ir the extremity of the acromion: fourthly, in the
posterior border. The acromion process, besides being formed of two separate
nuclei, has its base formed by an extension into it of the centre of ossification
which belongs to the spine, the extent of which varies in different cases. The
two separate nuclei unite, and then join with tlic extensicm carried in from the
spine, Tiicsc various epiphyses become joined to the bone between the ages
of twenty-two and twenty-five years. Sometimes failure of union between the
HUMERUS.
223
acromion process and spine occurs, the junction being effected by fibrous tissue,
or by an imperfect articulation; in some cases of supposed fracture of the
acromion with ligamentous union, it is probable that the detached segment was
never united to the rest of the bone.
Fig. 179. — Plaa of the Development of the Scapula, By Seven Centres.
^ferio'^
The epiphyses (except one for the coracoid process) appear from fifteen to seventeen
years, and unite between twenty-two and twenty-five years of age.
Articulations. With the humerus and clavicle.
Attachment of Muscles. To the anterior surface, the Subscapularis , posterior
surface, Supraspinatus, Infraspinatus ; spine. Trapezius, Deltoid ; superior border,
Omo-hyoid; vertebral border, Serratus magnus. Levator angali scapulae, Ehom-
boideus, minor and major; axillary border. Triceps, Teres minor. Teres major;
glenoid cavity, long head of the Biceps; coracoid process, short head of the
Biceps, Coraco-brachialis, Pectoralis minor; acromion process, the Platysma;
and to the inferior angle occasionally a few fibres of the Latissimus dorsi.
The Humeeus.
The Humerus is the longest and largest bone of the upper extremity; it
presents for examination a shaft and two extremities.
The Upper Extremity is the largest part of the bone; it presents a rounded
head, joined to the shaft by a constricted part, called the neck, and two other
eminences, the greater and lesser tuberosities (Fig. 180).
The head^ nearly hemispherical in form, is directed upwards, inwards, and a
little backwards ; its surface is smooth, coated with cartilage in the recent state,
and articulates with the glenoid cavity of the scapula. The circumference of
its articular surface is slightly constricted, and is termed the anatomical neck., in
224
THE SKELETON.
Fig. 180. — Left Humerus. Anterior View.
Cttl"%
^^'
/:\'^-i
f^^J^^:
y
'i/y>'
V.Vfsi
2J-\i
iSuTgicaJ Neck -
It' '
iU
-m
SUPINATOR RA3I1 10IJCU8
(fXTtliSOa OAilPl R;iDIALia
LQNCIO P
ComTtunt Oriyl.n ^^ \
^ ^-
FLEXOR CARfl RADIALla
PALMARIS L0NCU8
FLLXOR DICITORUM BUOLIMltt
,, CARPI ULNARIO
'^
>j
— "f
\. CXTENSOR. CARP. BAD. BREU
rOBDM COMMUNIS
.^^
., MIMIMI DICITI
„ CARPI ULW4RIS
SUPIM*TOn BREVIS
HUMERUS. 225
contradistinction to the constriction which exists below the tuberosities. The
latter is called the surgical nech^ from its often being the seat of fracture. It
* sliould be remembered, however, that fracture of the anatomical nech does some-
times, though rarely, occur.
The anatomical neck is obliquely directed, forming an obtuse angle with the
shaft. It is more distinctly marked in the lower half of its circumference than
in the upper half, where it presents a narrow groove, separating the head from
. the tuberosities. Its circumference affords attachment to the capsular ligament,
and is perforated by numerous vascular foramina.
The greater tuberosity is situated on the outer side of the head and lesser
tuberosity. Its upper surface is rounded and marked by three flat facets, sepa-
rated by two slight' ridges : the anterior facet gives attachment to the tendon
of the Supraspinatus : the middle one to the Infraspinatus ; the posterior facet,
and the shaft of the bone below it, to the Teres minor. The outer surface of
the great tuberosity is convex, rough, and continuous with the outer side of the
shaft.
The lesser tuberosity is more prominent, although smaller, than the greater:
it is situated in front of the head, and is directed inwards and forwards. Its
summit presents a prominent facet for the insertion of the tendon of the Sub-
scapularis muscle. The tuberosities are separated from one another by a deep
groove, the hicijntal groove^ so called from its lodging the long tendon of the
Biceps muscle, with which runs a branch of the anterior circumflex artery. It
commences above between the two tuberosities, passes obliquely downwards and
a little inwards, and terminates at the junction of the upper with the middle
third of the bone. It is deep and narrow at the commencement, and becomes
shallow and a little broader as it descends. In the recent state it is covered
with a thin layer of cartilage, lined by a prolongation of the synovial membrane
of the shoulder-joint, and receives part of the tendon of insertion of the Latissi-
mus dorsi about its centre.
The Shaft of the humerus is almost cylindrical in the upper half of its extent,
prismatic and flattened below, and presents three borders and three surfaces for
examination.
The anterior border runs from the front of the great tuberosity above to the
coronoid depression below, separating the internal from the external surface.
Its upper part is very prominent and rough, forms the outer lip of the bicipital
groove, and serves for the attachment of the tendon of the Pectoralis major.
About its centre is seen the rough deltoid impression ; below, it is smooth and
rounded, affording attachment to the Brachialis anticus.
The external border runs from the back part of the greater tuberosity to the
external condyle, and separates the external from the posterior surface. It is
rounded and indistinctly marked in its upper half, serving for the attachment
of the external head of the Triceps muscle ; its centre is traversed by a broad
but shallow oblique depression, the musculo-spiral groove; its lower part is
marked by a prominent rough margin, a little curved from behind forwards,
which presents an anterior lip for the attachment of the. Supinator longus above
and Extensor carpi radialis longior below, a posterior lip for the Triceps, and
an interstice for the attachment of the external intermuscular septum.
The internal border extends from the lesser tuberosity to the internal condyle.
Its upper third is marked by a prominent ridge, forming the inner lip of the
bicipital groove, and gives attachment from above downwards to the tendons of
the Latissimus dorsi. Teres major, and part of the origin of the inner head of the
Triceps. About its centre is a rough ridge for the attachment of the Coraco-
brachialis, and just below this is seen the entrance of the nutrient canal directed
downwards. Sometimes there is a second canal higher up, which takes a similar
direction. The inferior third of this border is raised into a slight ridge, which
becomes very prominent below; it presents an anterior lip for the attachment
15
226 THE SKELETON.
of tlie Brachialis anticus, a posterior lip for the internal head of the Triceps, and
an intermediate space for the internal intermuscular septum.
The external surface is directed outwards above, where it is smooth, rounded,
and covered by the Deltoid muscle; forwards below, where it is slightly concave
from above downwards, and gives origin to part of the Brachialis anticus muscle.
About the middle of this surface is seen a rough triangular impression for the
insertion of the Deltoid muscle; and below it the musculo-spiral groove, directed
obliquely from behind, forwards, and downwards, and transmitting the musculo-
spiral nerve and superior profunda artery.
The internal surface^ less extensive than the external, is directed forwards
above, forwards and inwards below : at its upper part it is narrow, and forms the
bicipital groove. The middle part of this surface is slightly rough for the attach-
ment of the Coraco-brachialis ; its lower part is smooth, concave, and gives
attachment to the Brachialis anticus muscle.*
The 'posterior surface (Fig. 181) appears somewhat twisted, so that its upper
part is directed a little inwards, its lower part backwards and a little outwards.
Nearly the whole of this surface is covered by the external and internal heads of
the Triceps, the former of which is attached to its upper and outer part, the latter
to its inner and back part, the two being separated by the musculo-spiral groove.
The Lower Extremity is flattened from before backwards, and curved slightly
forwards ; it terminates below in a broad articular surface, which is divided into
two parts by a slight ridge. On either side of the articular surface are the
external and internal condyles. The articular surface extends a little lower than
the condyles, and is curved slightly forwards, so as to occupy the more anterior
part of the bone; its greatest breadth is in the transverse diameter, and it is
obliquely directed, so that its inner extremity occupies a lower level than the
outer. The outer portion of the articular surface presents a smooth rounded
eminence, which has received the name of the lesser or radial head of the
humerus ; it articulates with the cup-shaped depression on the head of the radius,
and is limited to the front and lower part of the bone, not extending as far back
as the other portion of the articular surface. On the inner side of this eminence
is a shallow groove, in which is received the inner margin of the head of the
radius. The inner or trochlear portion of the articular surface presents a deep
depression between two well-marked borders. This surface is convex from
before backwards, concave from side to side, and occupies the anterior lower and
posterior parts of the bone. The external border, less prominent than the
internal, corresponds to the interval between the radius and the ulna. The in-
ternal border is thicker, more prominent, and consequently of greater length tlian
the external. The grooved portion of the articular surface fits accurately within
the greater sigmoid cavity of the ulna ; it is broader and deeper on the posterior
than on the anterior aspect of the bone, and is inclined obliquely from behind
forwards, and from without inwards. Above the back part of the trochlear
surface is a deep triangular depression, the olecranon fossa, in which is received
' A Rmall hnok-sliapod process of bone, varyinp: from -f',^ to \ of an inch in length, is not unfre-
fjuenlly foiuxl iirojectinp^ from tlie inner s'.irface of the shaft of the humerus two inches above the
internal condyle. It is curved downwards, forwards, and inwards, and its pointed extremity is
connected to the internal border, just above the inner condyle, l)y a lijj'anient or fibrous band ;
complctinf,' an arch, throufyh wliicii the median nerve and brachial artery pass, when these struc-
turcK deviate from their usual course. Sometimes the nerve alone is transmitted throuph it. or
the nerve may be accompanied by the ulnar-interosseous artery, in cases of hi<;h division of the
brachial. A well-marked {.'roove is usually found behind the process, in which the nerve and
artery are lodfred. 'I'his spjice is analofjous to the snpracondyloid foramen in many animals, and
proliably Herves in them to ])rotect the nerve and artery IVoin compression diiriiif,'' t Ih> contraction
of the muscles in this reirion. A detailed accmnit of this process is given by Dr. Sirutliers. in his
" Anatomical and ['hysiologiciil Observations." p. '202. An accessory portion of the (!oraco-bra-
chialis muscle is fref|uently connected with this process, according to JNIr. J. AVood : Journal of
Anat, and Pliy. No. 1, Nov. 18CG, p. 47.
HUMERUS.
227
the summit of the olecranon process in exten-
sion of the forearm. Above the front part of
the trochlear surface is seen a smaller depres-
sion, the coronoid fossa, which receives the coro-
noid process of the ulna during flexion of the
forearm. These fossae are separated from one
another by a thin transparent lamina of bone,
which is sometimes perforated ; their margins
afford attachment to the anterior and posterior
ligaments of the elbow -joint, and they are lined
in the recent state by the synovial membrane
of this articulation. Above the front part of
the radial tuberosity is seen a slight depres-
sion which receives the anterior border of the
head of the radius when the forearm is strongly
flexed. The external condyle is a small tuber-
cular eminence, less prominent than the internal,
curved a little forwards, and giving attachment
to the external lateral ligament of the elbow-
joint, and to a tendon common to the origin of
some of the extensor and supinator muscles.
The internal condyle, larger and more promi-
nent than the external, is directed a little back-
wards : it gives attachment to the internal late-
ral ligament, to the Pronator radii teres, and to
a tendon common to the origin of some of the
flexor muscles of the forearm. The ulnar nerve
runs in a groove at the back of the internal con-
dyle, or between it and the olecranon process.
These eminences are directly continuous above
with the external and internal borders. The
great prominence of the inner one renders it
more liable to fracture.
Structures. The extremities consist of can-
cellous tissue, covered with a thin compact
layer; the shaft is composed of a cylinder of
compact tissue, thicker at the centre than at the
extremities, and hollowed out by a large me-
dullary canal, which extends along its whole
length.
Developr)%ent. By seven centres (Fig. 182):
one for the shaft, one for the head, one for the
greater tuberosity, one for the radial head, one
for the trochlear portion of the articular surface,
and one for each condyle. The centre for the
shaft appears very early, soon after ossification
has commenced in the clavicle, and soon extends
towards the extremities. At birth the humerus
is ossified nearly in its whole length, the extremi-
ties remaining cartilaginous. Between the first
and second years ossification commences in the
head of the bone, and between the second and
third years the centre for the tuberosities makes
its appearance, usually by a single ossific point,
but sometimes, according to Beolard, by one
for each tuberosity, that for the lesser being
small, and not appearing until after the fourth
Fig. 181.— Left Humerus.
Posterior Surface.
Sr:.ipi
^
I
***•• *
\Jrockl%
228
THE SKELETON.
Fig. 182. — Plan of the Development of the
Humerus. By Seven Centres.
EpipJiysesefHead & i y^
luderositt'ex hlenil at y^'
S.u^ct7id unite i
li'itA Shixftat 20*!^ II r]
With, the glenoid cavity
and with the ulna and
year. By the fifth year the centres for the head and tuberosities have enlarged
and become joined, so as to form a siuglelarge epiphysis.
The lower end of the humerus is developed in the following manner : At
the end of the second year ossification commences in the radial portion of the
articular surface, and from this point extends inwards, so as to form the chief
part of the articular end of the bone, the centre for the inner part of the
articular surface not appearing until about the age of twelve. Ossification com-
mences in the internal condyle about the fifth year, and in the external one not
until about the thirteenth or fourteenth
year. About the sixteenth or seventeenth
year the outer condyle and both portions
of the articulating surface (having already
joined) unite with the shaft: at eighteen
years the inner condyle becomes joined,
whilst the upper epiphysis, although the
first formed, is not united until about the
twentieth year.
Articulations.
of the scapula,
radius.
Attachment of Muscles. To the greater
tuberosity, the Supraspinatus, Infraspi-
natus, and Teres minor; to the lesser tube-
rosity, the Subscapularis ; to the anterior
bicipital ridge, the Pectoralis major ; to
the posterior bicipital ridge ard groove,
the Latissimus dorsi and Teres major; to
the shaft, the Deltoid, Coraco-brachialis,
Brachialis anticus, external and internal
heads of the Triceps ; to the internal con-
dyle, the Pronator radii teres, and common
tendon of the Flexor carpi radialis, Pal-
maris longus. Flexor digitorum sublimis,
and Flexor carpi ulnaris : to the external
condyloid ridge, the Supinator longus, and
Extensor carpi radialis longior ; to the
external condyle, the common tendon of
the Extensor carpi radialis brevior. Ex-
tensor communis digitorum. Extensor
minimi digiti, and Extensor carpi ulnaris, the Anconeus and Supinator brevis.
The Forearm is that portion of the upper extremity which is situated between
the elVjow and wrist. It is composed of two bones, the Ulna and the Eadius.
Vnites w/ffi
Shaft at
The Ulna.
The Ulna (Figs. 183, 184), so called from its forming the elbow (lixtn?), is a
long bone, prismatic in form, placed at the inner side of the forearm, parallel
with the radius. It is the larger and longer of the two bones. Its upper
extremity, of great thickness and strength, forms a large part of the articula-
tion of the elbow-joint; it diminishes in size from above downwards, its lower
extremity being very small, and excluded from the wrist-joint by the interposi-
tion of WW iutcrarticiihir fibro-cartilage. It is divisible into a shaft, and two
extremities.
The Upper Extremity^ the strongest part of the bone, presents for examina-
lirm two large curved ])rocesscs, the Olecranon process and the Coronoid process ;
jiiid two concave arlicnliir cavities, the greater and lesser Sigmoid cavities,
^J'iie Olecranon, Process (lixu'j?, elbow ; xpdvoj/, head) is a large thick curved
ULNA.
229
Fig. 183. — Bones of Left Forearm. Anterior Surface.
^
■11 Mr '"m
RADIUS
flEKOR DIOITORU
SUSLIIVilS
PRO IM ATOR
RADII. TERES
tjf rtexoR LONcus poiLicis W.*' teW
RadiaZ Oi
<cai.7b
fLEXOR OICITORUM
SUeLIMIS
SUPINATOR LONCUS
Styloid JProces.
•EXT. 0SS13
MtrTACARP) POLLICI*?
INTEBNODIl P0111CI9
Vfyloial J^rocesa
230 TI-U: SKELETON.
eminence, situated at the upper and back part of tlie ulna. It rises somewliat
liiglier than the coronoid, and is curved forwards at the summit so as to present
n prominent tip, its base being contracted wliere it joins the sliaft. This is tire
narrowest part of the upper end of the ulna, and consequently, the most usual
seat of fracture. The posterior surface of the olecranon, directed backwards,
is triangular, smooth, subcutaneous, and covered bj a bursa. Its upper surface,
directed upwards, is of a quadrilateral form, marked behind by a rough impres-
sion for the attachment of the Triceps muscle ; and in front, near the margin,
by a slight transverse groove for the attachment of part of the posterior liga-
ment of the elbow-joint. Its anterior surface is smooth, concave, covered with
cartilage in the recent state, and forms the upper and back part of the great
sigmoid cavity. The lateral borders present a continuation of the same groove
that was seen on the margin of the superior surface ; they serve for the attach-
ment of ligaments, viz., the back part of the internal lateral ligament internally,
the posterior ligament externally. The Olecranon process, in its structure as
well as in its position and use, resembles the Patella in the lower limb ; and, like
it, sometimes exists as a separate piece, not united to the rest of the bone.^
The Coronoid Process (xoptoi/j^, a croio's beak) is a rough triangular eminence of
bone which projects horizontally forwards from the upper and front part of the
ulna, forming the lower part of the great sigmoid cavity. Its base is con-
tinuous with the shaft, and of considerable strength, so much so that fracture
of it is an accident of rare occurrence. Its apex is pointed, slightly curved up-
wards, and received into the coronoid depression of the humerus in flexion of
the forearm. Its upper surface is sriiooth, concave, and forms the lower part
of the great sigmoid cavity. The under surface is concave, and marked inter-
nally by a rough impression for the insertion of the Brachialis anticus. At the
junction of this surface with the shaft is a rough eminence, the tubercle of the
ulna, for the attachment of the oblique ligament. Its outer surface presents a
narrow, oblong, articular depression, the lesser sigmoid cavity. The inner sur-
face, by its prominent free margin, serves for the attachment of part of the
internal lateral ligament. At the front part of this surface is a small rounded
eminence for the attachment of one head of the Flexor digitorum sublimis, behind
the eminence, a depression for part of the origin of the Flexor profundus digi-
torum, and descending from the eminence, a ridge, which gives attachment to
one head of the Pronator radii teres. Occasionally, the Flexor longus pollicis
arises from the lower part of the Coronoid process by a rounded bundle of
muscular fibres.
The Greater Sigmoid Cavity^ so called from its resemblance to the old shape
of the Greek letter 2, is a semilunar depression of large size, formed by the
olecranon and coronoid processes, and serving for articulation with the trochlear
surface of the humerus. About the middle of either lateral border of this
cavity is a notch, which contracts it somewhat, and serves to indicate the junc-
tion of the two processes of which it is formed. The cavity is concave from
above dowuAvards, and divided into two lateral parts by a smooth, elevated
ridge, wliicli runs from tlic summit of the olecranon to the tip of the coronoid
])rocess. Of these two portions, the internal is the larger; it is slightly concave
transversely, the external portion being nearly plane from side to side.
Tlie Lesser Sujmoid Cavity is a narrow, oblong, articular depression, placed on
the outer side of the coronoid process, and serving for articulation with the head
of the radius. It is concave from before backwards ; and its extremities, A\diich
are prominent, serve for the attachment of the orbicular ligiuncnt.
Tlie Hhdft is prismatic in ^^a'\\\ at its u]:)per part, and cni'vcd rr(^ni bcLind
forwards, and from williiii oni wards, so as to be convex behind and cxtci'ually;
' Profopfjor Owon ropr^rds llio olcrranon as liomnloirnua not with the patella, but wUli an cx-
IcnsifiM fpf llif njipor 'mhI of flic filmla nlxivo tlio kncc-ioint. wliich is met with in the Ornitho-
rliyiidius, KcliidiKi, nnl sonic ollicr aiiiiiiiils. (Owkn, " On Iha Nature of Jji7nbs.")
ULNA. 231
its central part is quite straight; its lower part rounded, smooth, and bent a
little outwards ; it tapers gradually from above downwards, and presents for
examination three borders, and three surfaces.
The anterior border commences above at the prominent inner angle of the
coronoid process, and terminates below in front of the styloid process. It is well
marked above, smooth and rounded in the middle of its extent, and affords
attachment to the Flexor profundus digitorum : sharp and prominent in its
lower fourth for the attachment of the Pronator quadratus. It separates the
anterior from the internal surface.
The posterior border commences above at the apex of the triangular surface at
the back part of the olecranon, and terminates below at the back part of the
styloid process ; it is well marked in the upper three-fourths, and gives attach-
ment to an aponeurosis common to the Flexor carpi ulnaris, the Extensor carpi
ulnaris, and the Flexor profundus digitorum muscles ; its lower fourth is smooth
and rounded. This border separates the internal from the posterior surface.
The external or interosseous border commences above by two lines, which con-
verge one from each extremity of the lesser sigmoid cavity, inclosing between
them a triangular space for the attachment of part of the Supinator brevis, and
terminates below at the middle of the head of the ulna. Its two middle fourths
are very prominent, and serve for the attachment of the interosseous membrane ;
its lower fourth is smooth and rounded. This border separates the anterior
from the posterior surface.
The anterior surface^ much broader above than below, is concave in the upper
three-fourths of its extent, and affords attachment to the Flexor profundus digi-
torum ; its lower fourth, also concave, to the Pronator quadratus. The lower
fourth is separated from the remaining portion of the bone by a prominent ridge,
directed obliquely from above downwards and inwards ; this ridge marks the
extent of attachment of the Pronator above. At the junction of the upper with
the middle third of the bone is the nutrient canal, directed obliquely upwards
and inwards.
The posterior surface^ directed backwards and outwards, is broad and concave
above, somewhat narrower and convex in the middle of its course, narrow,
smooth, and rounded below. It presents above an oblique ridge, which runs
from the posterior extremity of the lesser sigmoid cavity, downwards to the
posterior border ; the triangular surface above this ridge receives the insertion
of the Anconeiis muscle, whilst the ridge itself affords attachment to the Supi-
nator brevis. The surface of bone below this is subdivided by a longitudinal
ridge, sometimes called the perpendicular line, into two parts : the internal part
is smooth, concave, and gives origin to (occasionally is merely covered by) the
Extensor carpi ulnaris ; the external portion, wider and rougher, gives attach-
ment from above downwards to part of the Supinator brevis, the Extensor ossis
metacarpi poUicis, the Extensor secundi internodii pollicis, and the Extensor
indicis muscles.
The internal surface is broad and concave above, narrow and convex below.
It gives attachment by its upper three-fourths to the Flexor profundus digitorum
muscle : its lower fourth is subcutaneous.
The Lower Extremity of the ulna is of small size, and excluded from the
articulation of the wrist-joint. It presents for examination two eminences, the
outer and larger of which is a rounded articular eminence, termed the head of
the ulna ; the inner, narrower and more projecting, is a non-articular eminence,
the styloid process. The head presents an articular facet, part of which, of an
oval form, is directed downwards, and plays on the surface of the triangalar
fibro-cartilage, which separates this bone from the wrist-joint ; the remaining
portion, directed outwards, is narrow, convex, and received into the sigmoid
cavity of the radius. The styloid process projects from the inner and back part
of the bone, and descends a little lower than the head, terminating in a rounded
summit, which affords attachment to the internal lateral ligament of the wrist.
232
THE SKELETON.
Fig. 184.- Bone of the Left Forearm. Posterior Surface.
ULNA
fm EXT. CARPI RAD.LONC
EAT.CAKI'I RAD. UREVinP,
fXT. CECUI4D1 INTrrrMCDII POLLiClik
TLEXOR OICITORUM
3UBLIMIS
EVT. CARPI l/LNAR.
t XT. I MDICIS
EXT, OICITORUM COMMUNIS
EXT. MINimi DIQITI
EADIUS,
233
Fig. 185.— Plan of the Development of tho
Ulna. By Three Centres.
OleeraTdffyi
Ap£ca rs at W^fi yi-l[^^^S\^-Joiiui SJtaft ac fOff if
iShtfl
The head is separated from the styloid process by a depression for the attach-
ment of the triangular interarticukr tibro-cartilage ; and behind, by a shallow
groove for the passage of the tendon of the Extensor carpi ulnaris.
Structure. Similar to that of the other long bones.
Develoioment. By three centres: one for the shaft, one for the inferior ex-
tremity, and one for the olecranon (Fig. 185). Ossification commences near the
middle of the shaft about the fifth week, and soon extend 3 through the greater
part of the bone. At birth the ends are cartilaginous. About the fourth year,
a separate osseous nucleus appears in the middle of the head, which soon ex-
tends into the styloid process. About the tenth year, ossific matter appears in
the olecranon near its extremity, the chief
part of this process being formed from an
extension of the shaft of the bone into it.
At about the sixteenth year, the upper
epiphysis becomes joined, and at about the
twentieth year the lower one.
Articulations. With the humerus and
radius.
Attachment of Muscles. To the olecra-
non : the Triceps, Anconeus, and one head
of the Flexor carpi ulnaris. To the coro-
noid process : the Brachialis anticus. Pro-
nator radii teres, Flexor sublimis digito-
rum, and Flexor profundus digitorum,
occasionally also the Flexor longus polli-
cis. To the shaft : the Flexor profundus
digitorum, Pronator quadratus. Flexor
carpi ulnaris. Extensor carpi ulnaris. An-
coneus, Supinator brevis. Extensor ossis
metacarpi pollicis, Extensor secundi inter-
nodii pollicis, and Extensor indicis.
The Radius.
The Radius is situated on the outer side
of the forearm, lying parallel with the
u.lna, which exceeds it in length and size.
Its upper end is small, and forms only a
small part of the elbow-joint; but its lower end is large, and forms the chief
part of the wrist. It is one of the long bones, prismatic in form, slightly curved
longitudinally, and like other long bones has a shaft and two extremities.
The Uijper Extremity presents a head, neck, and tuberosity. The head is of a
cylindrical form, depressed on its upper surface into a shallow cup, which articu-
lates with the radial or lesser head of the humerus in flexion of the joint.
Around the circumference of the head is a smooth articular surface, coated with
cartilage in the recent state, broad internally where it rotates within the lesser
sigmoid cavity of the ulna ; narrow in the rest of its circumference, to play in the
orbicular ligament. The head is supported on a round, smooth, and constricted
portion of bone, called the neck^ which presents, behind, a slight ridge, for the
attachment of part of the Supinator brevis. Beneath the neck, at the inner and
front aspect of the bone, is a rough eminence, the tuberosity. Its surface is
divided into two parts by a vertical line — a posterior rough portion, for the
insertion of the tendon of the Biceps muscle ; and an anterior smooth portion,
on which a bursa is interposed between the tendon and the bone.
The Shaft of the bone is prismoid in form, narrower above than below, and
slightly curved, so as to be convex outwards. It presents three surfaces, sepa-
rated by three borders.
A^exrs at 4**y^
Y^oins SJiirft at ZO^ '/■
234 THE SKELETON.
Tlie anterior harder extends from tlie lower part of the tuberosity above, to
the anterior part of the base of the styloid process below. It separates the
anterior from the external surface. Its iipper third is very prominent ; and
from its oblique direction, downwards and outwards, has received the name of
the ohlique line of the radius. It gives attachment, externally, to the Supinator
brevis ; internally, to the Flexor longus poUicis, and between these to the Flexor
digitorum sublimis. The middle third of the anterior border is indistinct and
rounded. Its lower fourth is sharp, prominent, affords attachment to the Pro-
nator quadratus, and terminates in a small tubercle, into which is inserted the
tendon of the Supinator longus.
The posterior border commences above, at the back part of the neck of the
radius, and terminates below, at the posterior part of the base of the styloid
process ; it separates the posterior from the external surface. It is indistinct
above and below, but well marked in the middle third of the bone.
The internal or interosseous border commences above, at the back part of the
tuberosity, where it is rounded and indistinct, becomes sharp and prominent as
it descends, and at its lower part bifurcates into two ridges, which descend to
the anterior and posterior margins of the sigmoid cavity. This border separates
the anterior from the posterior surface, and has the interosseous membrane at-
tached to it throughout the greater part of its extent.
The anterior surface is narrow and concave for its upper two-thirds, and gives
attachment to the Flexor longus pollicis muscle ; below, it is broad and flat, and
gives attachment to the Pronator quadratus. At the junction of the upper and
middle thirds of this surface is the nutrient foramen, which is directed obliquely
upwards.
The posterior surface is rounded, convex and smooth, in the upper third of its
extent, and covered by the Supinator brevis muscle. Its middle third is broad,-
slightly concave, and gives attachment to the Extensor ossis metacarpi pollicis
above, the Extensor primi internodii pollicis below. Its lower third is broad,
convex, and covered by the tendons of the muscles, which subsequently run in
the grooves on the lower end of the bone.
The external surface is rounded and convex throughout its entire extent. Its
upper third gives attachment to the Supinator brevis muscle. About its centre
is seen a rough ridge, for the insertion of the Pronator radii teres muscle. Its
lower part is narrow, and covered by the tendons of the Extensor ossis meta-
carpi pollicis and Extensor primi internodii pollicis muscles.
The Lower Extremity of the radius is large, of quadrilateral form, and provided
with two articular surfaces, one at the extremity for articulation with the carpus,
and one at the inner side of the bone for articulation with the ulna. The carpal
articular surface is of triangular form, concave, smooth, and divided by a slight
antero-posterior ridge into two parts. Of these, the external is large, of a trian-
gular form, and articulates with the scaphoid bone; the inner, smaller and
quadrilateral, articulates with the semilunar. The articular surface for the ulna
is called the si<jmoid cavity of the radius; it is narrow, concave, smooth, and
articulates with the head of the ulna. The circumference of this cud of the
bcmc presents three surfaces, an anterior, external, and posterior. The anterior
surface^ rough and irregular, affords attachment to the anterior ligament of the
wrist -joint. The external surface is prolonged obliquely downwards into a strong
conical projection, the styloid process, Avhich gives attachment by its base to
tlie tendon of the Supinator longus, and by its apex to the external lateral
ligament of the wrist-joint, Tlie outer surfiicc of this process is marked by two
grooves, wliich run obliquely downwards and forwards, and are separated from
one another by an elevated ridge. The anterior one gives passage to the tendon
of the Extensor ossis metacarpi ]iollicis, the posterior one to the tendon of the
Extensor primi internodii ])ollicis, Tlie posterior surface is convex, affords
attachment to the posterior ligfimcnt of tlie wrist, and is marked by three
grooves, I'roccediiig from wilhout inwards, the first groove is broad, but
CARPUS.
235
Fig. 186.— Plan of the Development of the
Radius. By Three Centres.
Aj'jjears at S ff' tJ- -
Pea^f^
) -Vnltf.
uv/h SAaft aho
shallow, and subdivided into two by a slightlj elevated ridge : the outer of these
two transmits the tendon of the Extensor carpi radialis longior, the inner the
tendon of the Extensor carpi radialis brevior. The second, which is near the
centre of the bone, is a deep but narrow groove, directed obliquely from above,
downwards and outwards; it transmits the tendon of the Extensor secundi
internodii pollicis. The third, lying most internall}^, is a broad groove, for the
passage of the tendons of the Extensor
communis digitorum, Extensor indicis
and Extensor minimi digiti; the ten-
don of the last-named muscle passing
through the groove at the point of
articulation of the radius with the ulna,
and lying in a separate sheath of the
annular ligament.
Structure. Similar to that of the
other long bones.
Development (Fig. 186). By three
centres: one for the shaft, and one for
each extremity. That for the shaft
makes its appearance near the centre
of the bone, soon after the development
of the humerus commences. At birth
the shaft is ossified, but the ends of the
bone are cartilaginous. About the end
of the second year, ossification com-
mences in the lower epiphysis; and
about the fifth year in the upper one.
At the age of puberty, the upper epi-
physis becomes joined to the shaft; the
lower epiphysis becoming united about
the twentieth year.
Articulations. With four bones : the
humerus, ulna, scaphoid, and semilunar.
Attachment of Muscles. To the tuberosity, the Biceps; to the oblique ridge,
the Supinator brevis, Flexor digitorum sublimis, and Flexor longus pollicis ; to
the shaft (its anterior surface), the Flexor longus pollicis and Pronator quad-
ratus; (its posterior surface), the Extensor ossis metacarpi pollicis and Extensor
primi internodii pollicis ; (its outer surface), the Pronator radii teres ; and to
the styloid process, the Supinator longus.
Appears at Z'f^i/-
'.TTnit/i-s with S'Jin ft nfiX
[^j.^trcmi
THE HAND.
The skeleton of the Hand is subdivided into three segments — the Carpus or
wrist bones, the Metacarpus or bones of the palm, and the Phalanges or bones
of the fingers.
The Carpus.
The bones of the Carpus, eight in number, are arranged in two rows. Those
of the upper row, enumerated from the radial to the ulnar side, are the scaphoid,
semilunar, cuneiform, and pisiform; those of the lower row, enumerated in the
same order, are the trapezium, trapezoid, os magnum, and unciform.
Common Chaeacters of the Carpal Bones.
Each bone (excepting the pisiform) presents six surfaces. Of these, the ante-
rior or palmar, and the posterior or dorsal, are rougli, for ligamentous attachment,
236 THE SKELETON.
tlie dorsal surface being generally the broader of tlie two. The superior and
inferior are articular, the superior generally convex, the interior concave ; and
the internal and external are also articular when in contact with contiguous
bones, otherwise rough and tubercular. Their structure in all is similar, con-
sisting within of cancellous tissue inclosed in a layer of compact bone. Each
bone is also developed from a single centre of ossification.
Bones of the Upper Eow. (Figs. 187, 188.)
The Scaphoid is the largest bone of the first row. It has received its name
from its fancied resemblance to a boat, being broad at one end, and narrowed
like a prow at the opposite. It is situated at the upper and outer part of the
carpus, its direction being from above downwards, outwards, and forwards. The
superior surface is conve±, smooth, of triangular shape, and articulates with the
lower end of the radius. The inferior surface^ directed downwards, outwards,
and backwards, is smooth, convex, also triangular, and divided by a slight ridge
into two parts, the external of which articulates with the trapezium, the inner
with the trapezoid. The posterior or dorsal surface presents a narrow, rough
groove, which runs the entire breadth of the bone, and serves for the attachment
of ligaments. The anterior oy palnnar surface is concave above, and elevated at
its lower and outer part into a prominent rounded tubercle, which projects
forwards from the front of the carpus, and gives attachment to the anterior
annular ligament of the wrist. The external surface is rough and narrow, and
gives attachment to the external lateral ligament of the wrist. The internal
surface presents two articular facets: of these, the superior or smaller one is
flattened, of semilunar form, and articulates with the semilunar ; the inferior or
larger is concave, forming, with the semilunar bone, a concavity for the hea'd
of the OS magnum.
Lay it with the dorsal surface, i. e., the narrow nonarticular grooved surface,
on the table, and the convex radial articular surface towards you. The tubercle
is outwards, i. e., points to the side to which the bone belongs.^
Articulations. With five bones: the radius above, trapezium and trapezoid
below, OS magnum and semilunar internally.
The Semilunar bone may be distinguished by its deep concavity and crescentic
outline. It is situated in the centre of the upper row of the carpus, between the
scaphoid and cuneiform. The superior surface^ convex, smooth, and bounded by
four edges, articulates with the radius. The inferior surface is deeply concave,
and of greater extent from before backwards than transversely ; it articulates
with the head of the os magnum, and by a long narroAV facet (separated by a
ridge from the general surface) with the unciform bone. The anterior or palmar
and posterior or dorsal surfaces are rough, for the attachment of ligaments, the
former being the broader, and of somewhat rounded form. The external surface
presents a narrow, flattened, semilunar facet, for articulation with the scaplund.
The internal surface is marked by a smooth, quadrilateral facet for articulation
with the cuneiform.
Lay it with the broader non-articular surface upwards and the semiluncs
forwards (?'. e., away from you). The broader semilunar surface, that for the os
magnum, will be on the side to which the bone belongs. If the ridge between
the two semiluncs is absent or ill-marked, the crescentic surface for the scaphoid
will be on the side to which the bone belongs.
Articulations. With five bones: the radius above, os magmiin and unciform
below, scaphoid and cuneiform on either side.
The Cuneiform [VOs P'/framidal) may be distinguished by its pyramidal sliape,
and by its having an oval, isolated facet, for articulation with the pisiform bone.
' In llicsf (lircctidiis ciuli hfnu; is supposed to bo jilncnl as it would lie if llic liand were liiid
supine oil tlie luliie in (Vont ul'tlie t^tudenl, with the wrist towards him.
CAEPUS.
237
I
It is situated at tTie upper and inner side of tlie carpus. The superior surface
presents an internal, rough, non-articular portion; and an external or articular
portion, which is convex, smooth, and' separated from the lower end of the ulna
bj the interarticular fibro-cartilage of the wrist. The inferior surface^ directed
Fig. 187. — Bones of the Left Hand. Dorsal Surface.
%^Row
rr^MoU/
238 THE SKELETON.
outwards, is concave, siiuionsly carved, and smooth for articulation witli tlie
unciform. Tlie posterior or dorsal surface is rough, for the attachment of liga-
ments. The anterior or ixilmar surface presents, at its inner side, an oval facet,
for articulation with the pisiform; and is rough externally, for ligamentous
attachment. The external surface^ the base of the pyramid, is marked by a flat,
quadrilateral, smooth facet, for articulation with the semilunar. The internal
surface^ the summit of the pyramid, is pointed and roughened, for the attachment
of the internal lateral ligament of the wrist.
Lay it with the surface on which the pisiform facet is upwards, and the con-
cavo-convex surface for the unciform in front. The base of the wedge {i. e., the
broad end of the bone) will be on the side to which it belongs.
Articulations. With three bones: the semilunar externally, the pisiform in
front, the imciform below, and with the triangular interarticular fibro-cartilage
which separates it from the lower end of the ulna.
The Pisiform bone may be known by its small size, and by its presenting a
single articular facet. It is situated at the anterior and inner side of the carpus,
is nearly circular in form, and presents on its posterior surface a smooth oval
facet, for articulation with the cuneiform bone. This facet approaches the supe-
rior, but not the inferior, border of the bone. The anterior or palmar surface is
rounded and rough, and gives attachment to the anterior annular ligament. The
outer and inner surfaces are also rough, the former being convex, the latter
usually concave.
Lay it with the articular facet on the table, and the non-articular part of the
same surface in front. The concave (inner) surface is then on the side to which
the bone does not belong, i. e., on the ulnar side.
Articulation. With one bone, the cuneiform.
Attachment of Muscles. To two : the Flexor carpi ulnaris, and Abductor
minimi digiti ; and to the anterior annular ligament.
Bones of the Lower Eow. (Figs. 187, 188.)
The Trapezium is of very irregular form. It may be distinguished by a deep
groove, for the tendon of the Flexor carpi radialis muscle. It is situated at the
external and inferior part of the carj^us, between the scaphoid and first meta-
carpal bone. The swperior surface^ concave and smooth, is directed upwards
and inwards, and articulates with the scaphoid. The inferior surface^ directed
downwards and outwards, is oval, concave from side to side, convex from before
backwards, so as to form a saddle-shaped -surface, for articulation with the base
of the first metacarpal bone. The anterior or palmar surface is narrow and
rough. At its u]3per part is a deep groove, running from above obliquely down-
wards and inwards; it transmits the tendon of the Flexor carpi radialis, and is
bounded externally by a prominent ridge, the oblique ridge of the trapezium.
This surface gives attachment to the Abductor polhcis. Flexor ossis mctacarpi,
and Flexor brevis pollicis muscles ; and the anterior annular ligament. The
posterior or dorsal surfa.ce is rough, and the external surf ace also broad aiid rough,
for the attachment of ligaments. The internal surface presents two articular
facets : the upper one, large and concave, articulates with the trapezoid ; the
lower one, narrow and flattened, with the base of the second metacarpal bone.
Lay it with its prominent ridge^ upwards and towards yourself. The saddle-
shaped surface for the tlnunb is cm the side to which the bone belongs.
Articulations. With four Ixmcs : the scaphoid above, the tra])czoid and
second metacarpal bones internally, the first metacarpal bcloAv.
Attachment of Muscles. Abductor pollicis, Flexor ossis mctacarpi, and part
of the Flexor brevis ])ollicis.
' 'I'lif jirotniiifiit rid^'-f is between the deep groove for tlie tendon of tlie Flexor carpi radialis
and the 7io//-;irti(;ular .surface.
CARPUS.
239
The Trapezoid is the smallest bone in the second row. It may be known by
its wedge-shaped form, the broad end of the wedge forming the dorsal, the
narrow end the palmar surface ; and by its having four articular surfaces touch-
ing each other, and separated by sharp edges. The superior surface^ quadri-
lateral in form, smooth and slightly concave, articulates with the scaphoid. The
inferior surface articulates with the upper end of the second metacarpal bone ;
Fig'. 188. — Bones of the Left Hand. Palmar Surface,
FLEXOR. CARPI ULNARIS
FLEICOH BREVIS NllNlMl DICITI
FLEXOR OSSIS WETaCARPl
MINIMI DICITI
*::.
MeJMeai'fiivs
rUCK. BREVIS
240 THE SKELETON.
it is convex from side to side, concave from before backwards, and subdivided
bj an elevated ridge, into two unequal lateral facets. The posterior or dorsal
and anterior or palmar surfaces are rough, for the attachment of ligaments, the
former being the larger of the two. The external surface^ convex and smooth,
articulates with the trapezium. The internal surface is concave and smooth
below, for articulation with the os magnum; rough above, for the attachment
of an interosseous ligament.
Lay it with its smaller non-articular surface upwards, and the edge which
ssparates the two concave articular facets forwards. The lower end of the bone
will then curve aivay from the side to which it belongs.^
Articulations. With four bones : the scaphoid above, second metacarpal bone
below, trapezium externally, os magnum internally.
Attachment of Muscles. Part of the Flexor brevis pollicis.
The Os Magnum is the largest bone of the carpus, and occupies the centre of
the wrist. It presents above a rounded portion or head, which is received into
the concavity formed by the scaphoid and semilunar bones ; a constricted portion
or neck ; and, below, the body. The superior surface is rounded, smooth, and
articulates with the semilunar. The inferior surface is divided by two ridges
into three facets, for articulation with the second, third, and fourth metacarpal
bones ; that for the third (the middle facet) being the largest of the three. The
posterior or dorsal surf ace is broad and rough; the anterior or palmar .^ narrow,
rounded, and also rough, for the attachment of ligaments. The external surf ace
articulates with the trapezoid by a small facet at its anterior inferior angle, behind
which is a rough depression for the attachment of an interosseous ligament.
Above this is a deep and rough groove, which forms part of the neck, and serves
for the attachment of ligaments, bounded superiorly by a smooth convex surface,
for articulation with the scaphoid. The internal surface articulates with the
unciform by a smooth, concave, oblong facet, which occupies its posterior and
superior parts ; and is rough in front, for the attachment of an interosseous
ligament.
Lay it on the table with the narrower (convex) non-articular surface upwards,
and the head towards you. The prominent corner at the lower anterior part
of the bone inclines away from the side to which it belongs.
Articulations. With seven bones : the scaphoid and semilunar above ; the
second, third, and fourth metacarpal below ; the trapezoid on the radial side ;
and the unciform on the ulnar side.
Attachment of Muscles. Part of the Flexor brevis pollicis.
The Unciform bone may be readily distinguished by its wedge-shaped form,
and the hook-like process that projects from its palmar surface. It is situated
at the inner and lower angle of the carpus, with its base downwards, resting on
the two inner metacarpal bones, and its apex directed upwards and outwards.
The supjerior surface^ the apex of the wedge, is narrow, convex, smooth, and
articulates with the semilunar. The inferior surface articulates with the fourth
and fifth metacarpal bones, the concave surface for each being separated by a
ridge, which runs from before backwards. The j^osterior or dorsal surface is
triangular and rough, for ligamentous attachment. The anterior or palmar
sv.rface presents, at its lower and inner side, a curved hook-like process of bone,
the unciform process, directed from the palmar surface forwards and outwards.
It gives attachment by its apex, to the annular ligament; by its inner surface,
to the Flexor brevis minimi digiti, and the Flexor ossjs metacarpi minimi digiti;
and is grooved on its outer side, for the passage of the Flexor tendons into the
' ir tlic l)f)n(' 1)1' not. well niiirkfd, llic follnwine mclliod, siioposlcd by Mr. K. J. Rpitta,
T)ciii()iiKlriitor of Aiiiitoiny at St. (;ci)rii(!'s Hospital S(-lio()l, will he foiiiKl rnoro sini])lo. Let the
BuiKM-ior — /. e. tin; siiuiotli (niiulriliitfinil iirticnlar— surface ])e flirectod towards the student, and
tlie posterior — tlie larjrer miiijli non-articular— surface upwards; tlie latter will tlien be found
to present a wedge-shuiied outline, the baae of which points to the side to which the bone
belong.s.
METACARPUS. 241
palm of the liand. This is one of the four eminences on the front of the carpus,
to which the anterior annular ligament is attached ; the others being the pisi-
form internally, the oblique ridge of the trapezium and the tuberosity of the
scaphoid externally. The internal surface articulates with the cuneiform by an
oblong facet, cut obliquely from above, downwards and inwards. The external
surface articulates with the os magnum by its upper and posterior part, the
remaining portion being rough, for the attachment of ligaments.
Lay it with the hooked process upwards, and the articular surface divided into
two parts for the metacarpal bones forwards. The concavity of the process will
be on the side to which the bone belongs.
Articulations. With five bones : the semilunar above, the fourth and fifth
metacarpal below, the cuneiform internally, the os magnum externally.
Attachment of Muscles. To two : the Flexor brevis minimi digiti, and Flexor
ossis metacarpi minimi digiti ; and to the anterior annular ligament.
Ti-iE Metacarpus.
The Metacarpal Bones are five in number : they are long cylindrical bones,
presenting for examination a shaft, and two extremities.
Common Characters of the Metacarpal Bones.
ThesAa/Hs prismoid in form, and curved longitudinally, so as to be convex in
the longitudinal direction behind, concave in front. It presents three surfaces ;
two lateral, and one posterior. The lateral surfaces are concave, for the attach-
ment of the Interossei muscles, and separated from one another by a prominent
line. The posterior or dorsal surface is triangular, smooth, and flattened below,
and covered, in the recent state, by the tendons of the Extensor muscles. In
its upper half it is divided by a ridge into two narrow lateral depressions, for the
attachment of the Dorsal interossei muscles. This ridge bifurcates a little above
the centre of the bone, and its branches run to the small tubercles on each side
of the digital extremity.
The carpal extreinity^ or hase^ is of a cuboidal form, and broader behind than
in front : it articulates above with the carpus, and on each side with the adjoining
metacarpal bones ; its dorsal and palmair surfaces being rough, for the attachment
of tendons and ligaments.
The digital extremity .^ or head^ presents an oblong surface, flattened at each side,
for articulation with the first phalanx ; it is broader, and extends farther forwards
in front than behind, and is longer in the antero-posterior than in the transverse
diameter. On either side of the head is a deep depression, surmounted by a
tubercle, for the attachment of the lateral ligament of the metacarpo-phalangeal
joint, ^h.e posterior surface.^ broad and fiat, supports the Extensor tendons ; the
anterior surface presents a median groove, bounded on each side by a tubercle,
for the passage of the Flexor tendons.
Peculiar Characters of the Metacarpal Bones.
The metacarp)al hone of the thumb is shorter and wider than the rest, diverges
to a greater degree from the carpus, and its palmar surface is directed inwards
towards the palm. The shaft is flattened and broad on its dorsal aspect, and does
not present the bifurcated ridge which is found on the other metacarpal bones ;
it is concave from before backwards on its palmar surface. The carpal extremity,
or lase^ presents a concavo-convex surface, for articulation with the trapezium,
and has no lateral facets. The digital extremity is less convex than that of the
other metacarpal bones, broader from side to side than from before backwards,
and terminates anteriorly in a small articular eminence on each side, over which
play two sesamoid bones.
16
242 THE SKELETON.
Tlie side to which this bone belongs may be known by observing the httle
facet, which is marked on tlie inner side of its posterior surface just above the
base, for the tendon of the Extensor ossis metacarpi polhcis. Mr. Hoklen directs
that the bone be placed with its dorsal surface upwards, and its head towards
the student, which is the reverse of the ordinary position. This facet will then
mark the side to which the bone belongs.
The metacarj^al hone of the index finger is the longest, and its base the largest
of the other four. Its carjiol extremity is prolonged upwards and inwards. The
dorsal and palmar surfaces of this extremity are rough, for the attachment of
tendons and ligaments. It presents four articular facets : the first, at the end
of the bone, is concave from side to side, convex from before backwards, and
articulates with the trapezoid; the second, on the radial side, is a flat quadri-
lateral facet, for the trapezium ; the third, which occupies the outer part of the
ulnar side of the extremity, is a long narrow facet, for the os magnum ; and the
fourth, which occupies the inner part of the same side, is a considerably broader
surface, for the third metacarpal bone.
The side to which this bone belongs is marked by the absence of the lateral
facet on the outer (radial) side of its head, so that if the bone be placed with its
base towards the student, and the palmar surface upwards, the side on which
there is no lateral facet will be that to which it belongs. If the head of the bone
be indistinctly marked, the base can be recognized, its ulnar or inner surface
being marked by the two long narrow facets for the os magnum and third meta-
carpal, easily distinguishable from the single quadrangular facet on the radial
side for the trapezium, which will then mark the side to which the bone belongs.
The metacarpal hone of the middle finger is a little smaller than the preceding ;
it presents a pyramidal eminence on the radial side of its base (dorsal aspect),
which extends upwards behind the os magnum. The carpal articular facet is
concave behind, flat and horizontal in front, and corresponds to the os magnum.
On the radial side is a smooth concave facet, for articulation with the second
metacarpal bone ; and on the ulnar side two small oval facets, for articulation
with the fourth metacarpal.
The side to which this bone belongs is easily recognized by the projecting
angle on the lower radial corner of its base. With the palmar surface upper-
most, and the base towards the student, this projection points towards the side
to which the bone belongs.
The metacarpal hone of the ringfinger is shorter and smaller than the pre-
ceding, and its base small and quadrilateral ; the carpal surface of the base pre-
senting two facets, for articulation with the unciform and os magnum. On the
radial side are two oval facets, for articulation with the third metacarpal bone;
and on the ulnar side a single concave facet, for the fifth metacarpal.
If this bone is placed with the base towards the student, and the palmar surface
upwards, the radial side of the base, which has two facets for articulation with
the third metacarpal bone, will be on the side to which it belongs. If, as some-
times happens in badly marked bones, one of these facets is indistinguishable,
the side may be known by the greatly larger size in such cases of the fe-cet for
the fifth metacarpal bone, which is therefore situated on the side to which the
bone does not belong.
The metacarpal hone of the little finger may be distinguished by the concavo-
convex form of its carpal surface, which articulates with tlic unciform; and by
its having only one lateral articular facet, which corresponds Avith the fimrth
metacarpal })ono. On its ulnar side is a prominent tubercle, for the insertion of
the t(;ndon ol' ilic I'].vtensor carpi ulnaris. The dorsal surface of the shaft is
marked by an ohliiinf. ridgo, wlricli extends from near the ulnar side of the upper
extremity to ilic. liidijil sidi- of the lower. The outer division of this surface
Hcrves for the atiaclmicnt oC the fourtli Dorsal interosseous muscle ; the inner
division is smooth, and covenjd by the Extensor tendons of the little finger.
If this bone is placed with its base towards the student, and ils palmar surface
PHALANGES. 243
■upwards, the side of the head which has a lateral facet will be that to which the
bone belongs.
Articulations. Besides the phalangeal articulations, the first metacarpal bone
articulates with the trapezium ; the second with the trapezium, trapezoides, os
magnum, and third metacarpal bones; the third with the os-magnum, and second
and fourth metacarpal bones ; the fourth with the os magnum, unciform, and
third and fifth metacarpal bones ; and the fifth with the unciform and fourth
metacarpal.
Attachment of Muscles. To the metacarpal bone of the thumb, three : the
Flexor ossis metacarpi poUicis, Extensor ossis metacarpi pollicis, and first Dorsal
interosseous. To the second metacarpal bone, five : the Flexor carpi radialis.
Extensor carpi radialis longior, first and second Dorsal interosseous, and first
Palmar interosseous. To the third, five : the Extensor carpi radialis brevior,
Flexor brevis pollicis, Adductor pollicis, and second and third Dorsal inter-
osseous. To the fourth, three : the third and fourth Dorsal and second Palmar
interosseous. To the fifth, five : the Extensor carpi ulnaris, Flexor carpi ulna-
ris. Flexor ossis metacarpi minimi digiti, fourth Dorsal, and third Palmar inter-
osseous.
Phalanges.
The Phalanges are the bones of the fingers; they are fourteen in number,
three for each finger, and two for the thumb. They are long bones, and present
for examination a shaft, and two extremities. The shaft tapers from above
downwards, is convex posteriorly, concave in front from above downwards, flat
from side to side, and marked laterally by rough ridges, which give attachment
to the fibrous sheaths of the Flexor tendons. The metacarpal extremity or hase^
in the first row, presents an oval concave articular surface, broader from side to
side than from before backwards ; and the same extremity in the other two
rows, a double concavity separated by a longitudinal median ridge, extending
from before backwards. The digital extremities are smaller than the -others, and
terminate, in the first and second row, in two small lateral condyles, separated
by a slight groove ; the articular surface being prolonged farther forwards on
the palmar than on the dorsal surface, especially in the first row.
The Ungual phalanges are convex on their dorsal, flat on their palmar sur-
faces ; they are recognized by their small size, and by a roughened elevated sur-
face of a horseshoe form on the palmar aspect of their ungual extremity, which
serves to support the sensitive pulp of the finger.
Articulations. The first row with the metacarpal bones, and the second row
of phalanges ; the second row with the first and third ; the third, with the
second row.
Attachment of Muscles. To the base of the first phalanx of the thumb, four
muscles : the Extensor primi internodii pollicis. Flexor brevis pollicis. Abductor
pollicis. Adductor pollicis. To the second phalanx, two: the Flexor longus
pollicis, and the Extensor secundi internodii. To the base of the first phalanx
of the index finger, the first Dorsal and the first Palmar interosseous ; to that
of the middle finger, the second and third Dorsal interosseous; to that of the
ring-finger, the fourth Dorsal and the second Palmar interosseous ; and to that
of the little finger, the third Palmar interosseous, the Flexor brevis minimi
digiti, and Abductor minimi digiti. To the second phalanges, the Flexor sub-
limis digitorum. Extensor communis digitorum ; and, in addition, the Extensor
indicis to the index finger, the Extensor minimi digiti to the little finger. To
the third phalanges, the Flexor profundus digitorum and Extensor communis
dig-itorum.
244
THE SKELETON.
Development of the Bones of the Hand.
The Carpal hones are each developed bj a single centre. At birth thev are
all cartilaginous. Ossification proceeds in the following order (Fig. 189) : in the
OS magnum and unciform an ossific point appears during the first year, the for-
mer preceding the latter ; in the cuneiform, at the third year ; in the trapezium
and semilunar, at the fifth year, the former preceding the latter ; in the scaphoid
at the sixth year ; in the trapezoid, during the eighth year ; and in the pisiform
about the twelfth year.
Fig. 189. — Plan of the Development of the Hand.
Carpus
1 centrefor ecwJi bone
All curTilarjinous at JiirlJi
Metacarpns
2 Centres for each hone
1for Sho^t
lfor JDi(jitu.I Extremity
Pha la nqes
2 Centres for each hone
I for Shaft
iforMetacctriial Ext'J.
The MetacMrpal hones are each developed by two centres : one for the shaft,
and one for the digital extremity, for the four mner metacarpal bones ; one for
the shaft, and one for the base, for the metacarpal bone of the thumb, which in
this respect resembles the phalanges. Ossification commences in the centre of
the shaft about the sixth week, and gradually proceeds to cither end of the
bone ; about the third year the digital extremities of the four inner metacarpal
bones, and tlie base of the first metacarpal, commence to ossify, and they unite
about the twentieth year.
The Phalancjes are each developed by tim centres: one for the sliaft, and one
for the base. Ossification (commences in the shaft, in all three rows, at about the
sixth week, and gradually involves the whole of the bone excc]iting the upper
extremity. Ossification of the base commences in the first row l)etwccn the
third and fourth years, and a year later in those of the second and third rows.
OS INNOMINATUM.
245
The two centres become united in each row, between the eighteenth and twen-
tieth years.
Of the Lower Extremity.
The Lower Extremity consists of three segments, the thigh, leg, and foot,
which correspond to the arm, forearm, and hand in the upper extremity. It is
connected to the trunk through the os innominatum, or haunch, which is homo-
logous with the shoulder.
The Os Innominatum.
The Os Innominatum, or nameless bone, so called from bearing no resemblance
to any known object, is a large irregular-shaped bone, which, with its fellow of
Fig. 190. — Right Os laQominatum. External Surface.
s '*
6 ^r
246
THE SKELETON.
the opposite side, forms tlie sides and anterior wall of the pelvic cavity. In
young subjects it consists of three separate parts, which meet and form the large
cup-like cavity, situated near the middle of the outer side of the bone ; and,
although in the adult these have become united, it is usual to describe the bone
as divisible into three portions — the ilium, the ischium, and the pubes.
The ilium, so called from its supporting the flank (ilia), is the superior broad
and expanded portion which runs upwards from the upper and back part of the
acetabulum, and forms the prominence of the hip.
The ischium {lax^ov, the hip) is the inferior and strongest portion of the bone ;
it proceeds downwards from the acetabulum, expands into a large tuberosity,
and then, curving upwards, forms with the descending ramus of the pubes a
large aperture, the obturator foramen.
Fia:. 191. — Eioht Os Innominatum. Internal Surface.
CRECTOK RSMIl
Th.0 pubes is tliat ])or1ioii wliicli runs horizontally iinvards from the inner side
of the acetabulum for aljout two inches, then makes a sudden bend, and descends
I
OS INNOMINATUM. 247
to the same extent : it forms tlie front of the pelvis, supports the external organs
of generation, and has received its name from being covered with hair.
The lliura presents for examination two surfaces, an external and an internal,
a crest, and two borders, an anterior and a posterior.
External Surface or Dorsuvi of the Ilium (Fig. 190). The back part of this
surface is directed backwards, downwards, and outwards; its front part forwards,
downwards, and outwards. It is smooth, convex in front, deeply concave
behind; bounded above by the crest, below by the upper border of the aceta-
bulum ; in front and behind, by the anterior and posterior borders. This sur-
face is crossed in an arched direction by three semicircular lines, the superior,
middle, and inferior curved lines. The superior curved line, the shortest of the
three, commences at the crest, about two inches in front of its posterior ex-
tremity ; it is at first distinctly marked, but as it passes downwards and outwards
to the upper part of the great sacro-sciatic notch, where it terminates, it becomes
less marked, and is often altogether lost. The rough surface included between
this line and the crest, affords attachment to part of the Gluteus maximus above,
and a few fibres of the Pyriformis below. The middle curved line, the longest
of the three, commences at the crest, about an inch behind its anterior extremity,
and, taking a curved direction downwards and backAvards, terminates at the
upper part of the great sacro-sciatic notch. The space between the middle and
superior curved lines and the crest is concave, and affords attachment to the
Gluteus medius muscle. Near the central part of this line may often be observed
the orifice of a nutrient foramen. The inferior curved line, the least distinct of
the three, commences in front at the upper part of the anterior inferior spinous
process, and taking a curved direction backwards and downwards, terminates
at the anterior part of the great sacro-sciatic notch. The surface of bone included
between the middle and inferior curved lines is concave from above downwards,
convex from before backwards, and affords attachment to the Gluteus minimiis
muscle. Beneath the inferior curved line, and corresponding to the upper part
of the acetabulum, is a smooth eminence (sometimes a depression), to which is
attached the reflected tendon of the Rectus femoris muscle.
The Internal surface (Fig. 191) of the ilium is bounded above by the crest,
below by a prominent line, the linea ilio-pectinea, and before and behind b}'" the
anterior and posterior borders. It presents anteriorly a large smooth concave
surface, called the internal iliac fossa, or venter of the ilium, which lodges the
Iliacus muscle, and presents at its lower part the orifice of a nutrient canal.
Behind the iliac fossa is a rough surface, divided into two portions, a superior
and an inferior. The inferior or auricular portion, so called from its resemblance
in shape to the ear, is coated with cartilage in the recent state, and articulates
with a surface of similar shape on the side of the sacrum. The superior portion
is concave and rough, for the attachment of the posterior sacro-iliac ligaments.
The crest of the ilium is convex in its general outline and sinuously curved,
being bent inwards anteriorljr, outwards posteriorly. It is longer in the female
than in the male, very thick behind, and thinner at the centre than at the extre-
mities. It terminates at either end in a prominent eminence, the anterior supe-
rior and posterior superior spinous process. The surface of the crest is broad,
and divided into an external lip, an internal lip, and an intermediate space.
To the external lip is attached the Tensor vaginae femoris, Obliquus externus
abdominis, and Latissimus dorsi, and by its whole length the fascia lata ; to the
interspace between the lips, the Internal oblique; to the internal lip, the Trans-
versalis, Quadratus lumborum, and Erector spinse, also the fascia iliaca.
The anterior border of the ilium is concave. It presents two projections,
separated by a notch. Of these, the uppermost, situated at the junction of the
crest and anterior border, is called the anterior superior spinous process of the
ilium, the outer border of which gives attachment to the fascia lata, and the
origin of the Tensor vaginae femoris; its inner border, to the Iliacus internus;
whilst its extremity affords attachment to Poupart's ligament, and the origin of
248 - THE SKELETON.
the Sartorius. Beneatli this eminence is a notch which gives attachment to the
Sartorius muscle, and across which passes the external cutaneous nerve. Below
the notch is the anterior inferior spinous process, which terminates in the upper
lip of the acetabulum ; it gives attachment to the straight tendon of the Eectus
femoris muscle. On the inner side of the anterior inferior spinous process is a
broad shallow groove, over which passes the Iliacus muscle. The posterior
border of the ilium, shorter than the anterior, also presents two projections
separated bj a notch, the posterior superior and the posterior inferior spinous
processes. The former corresponds with that portion of the posterior surface
of the ilium which serves for the attachment of the oblique portion of the sacro-
iliac ligaments and the Multifidus spinas; the latter to the auricular portion
which articulates with the sacrum. Below the posterior inferior spinous process
is a deep notch, the great sacro-sciatic.
The Ischium forms the lower and back part of the os innominatum. It is
divisible into a thick and solid portion, the body; the tuberosit_y, a large rough
eminence, on which the body rests in sitting ; and a thin ascending part, the
ramus.
The hody^ somewhat triangular in form, presents throe surfaces, external, in-
ternal, and posterior. The external surface corresponds to that portion of the
acetabulum formed by the ischium ; it is smooth and concave above, and forms
a little more than two-fifths of that cavity ; its outer margin is bounded by a
prominent rim or lip, to which the cotyloid fibro-cartilage is attached. Below
the acetabulum, between it and the tuberosity, is a deep groove, along which
the tendon of the Obturator externus muscle runs, as it passes outwards to be
inserted into the digital fossa of the femur The internal surface is smooth,
concave, and forms the lateral boundary of the true pelvic cavity ; it is broad
above, and separated from the venter of the ilium by the linea ilio-pectinea,'
narrow below; its posterior border is encroached upon, a little below its centre,
by the spine of the ischium, above and below which are the greater and lesser
sacro-sciatic notches; in front, it presents a sharp margin, which forms the outer
boundary of the obturator foramen. This surface is perforated by two or three
large vascular foramina, and ai^brds attachment to part of the Obturator in-
ternus muscle. The posterior surface is quadrilateral in form, broad and smooth
above, narrow below where it becomes continuous with the tuberosity; it is
limited in front, by the margin of the acetabulum ; behind, by the front part of
the great sacro-sciatic notch. This surface supports the Pyriformis, the two
Gemelli, and the Obturator internus muscles, in their passage outAvards to the
great trochanter. The body of the ischium presents three borders, posterior,
inferior, and internal. The posterior harder presents, a little below the centre,
a thin and pointed triangular eminence, the spine of the ischium, more or less
elongated in different subjects. Its external surface gives attachment to the
Gemellus superior, its internal surface to the Coccygcus and Levator aiii; whilst
to the pointed extremity is connected the lesser sacro-sciatic ligament. Above
the spine is a notch of large size, the great sacro-sciatic, converted into a foramen
by the lesser sacro-sciatic ligament; it transmits the Pyriformis muscle, the
gluteal vessels, and superior gluteal nerve passing out of the pelvis above the
muscle; the sciatic vessels, the greater and lesser sciatic nerves, the internal
pudic vessels and nerve, and a small nerve to the Obturator internus muscle
below it. Below the spine is a smaller notch, the lesser sacro-sciatic; it is
smooth, coated in the recent state with cartilage, the surface of which ])i'csents
numerous markings corrcs])onding to the subdivision of the tendon of the
Obturator internus which winds over it. It is converted into a foramen by the
sacro-sciatic ligaments, nnd Iransmits the tendon of the Obturator internus, the
nerve which supjilics tli;it iiiiis(;lc, and the internal ))ii( lie vessels and nerve.
The inferior harder is thick and broad; at ils point of junction witli the posterior
is the tuberosity of tlio iscliimn. ''I'hc internal horder is thin, and forms the
outer circumference of the (;btiirat<jr (bramen.
I
OS INNOMINATUM. 249
The tuberosity presents for examination an external lip, an internal lip, and
an intermediate space. The external lip gives attachment to the Quadratns
femoris, and part of the Adductor magnus muscles. The inner lip is bounded
by a sharp ridge, for the attachment of a falciform prolongation of the great
sacro-sciatic ligament ; it presents a groove on the inner side of this for the
lodgment of the internal pudic vessels and nerve ; and, more anteriorly, has
attached the Transversus perinsei and Erector penis muscles. The intermediate
surface presents four distinct impressions. Two of these, seen at the front part
of the tuberosity, are rough, elongated, and separated from each other by a
prominent ridge; the outer one gives attachment to the Adductor magnus, the
inner one to the great sacro-sciatic ligament. Two, situated at the back
part, are smooth, larger in size, and separated by an oblique ridge: from the
upper and outer arises the Semi-membranosus ; from the lower and inner, the
Biceps and Semi-tendinosus. The uppermost part of the tuberosity gives attach-
ment to the Gemellus inferior.
The ramus^ or ascending ramus^ is the thin flattened part of the ischium, which
ascends from the tuberosity upwards and inwards, and joins the ramus of the
pubes — their point of junction being indicated in the adult by a rough eminence.
The outer surface of the ramus is rouarh, for the attachment of the Obturator
externus muscle, also some fibres of the Adductor magnus, and of the Gracilis ;
its inner surface forms part of the anterior wall of the pelvis. Its inner border
is thick, rough, slightly everted, forms part of the outlet of the pelvis, and
serves for the attachment of the crus penis. Its outer border is thin and sharp,
and forms part of the inner margin of the obturator foramen.
The Puhes forms the anterior part of the os innominatum ; it is divisible into
a horizontal ramus or body, and a perpendicular ramus.
The hody^ or horizontal ramus^ presents for examination two extremities, an
outer and an inner, and four surfaces. The outer extremity^ the thickest part
of the bone, forms one-fifth of the cavity of the acetabulum ; it presents, above, a
rough eminence, the ilio-pectineal, which serves to indicate the point of junction
of the ilium and pubes. The inner extremity is the symphysis ; it is oval,
covered by eight or nine transverse ridges, or a series of nipple-like processes
arranged in rows, separated by grooves ; they serve for the attachment of the
connecting fibro-cartilage, placed between it and the opposite bone. The upper
surface^ triangular in form, wider externally than internally, is bounded behind
by a sharp ridge, the pectineal line; or linea ilio-pectinea, which, running out-
wards, marks the brim of the true pelvis. The surface of bone in front of the
pubic portion of the linea ilio-pectinea, serves for the attachment of the Pectineus
muscle. This ridge terminates internally at a tubercle, which projects forwards,
and is called the spine of the pubes. The portion of bone included betAveen the
spine and inner extremity of the pubes is called the crest ; it serves for the
attachment of the Rectus, Pyramidalis, and conjoined tendon of the Internal
oblique and Transversalis. The pointof junction of the crest with the symphy-
sis is called the amjle of the piihes. The inferior surface presents, externally, a
broad and deep obli(~[ue groove, for the passage of the obturator vessels and
nerve ; and, internally, a sharp margin, which forms part of the circumference
of the obturator foramen. Its external surface^ flat and compressed, serves for
the attachment of mnscles. Its internal surface, convex from above downwards,
concave from side to side, is smooth, and forms part of the anterior wall of the
pelvis.
The descending ramus of the pubes passes outwards and downwards, becoming
thinner and narrower as it descends, and joins with the ramus of the ischium.
Its external surface is rough, for the attachment of muscles; the Adductor mag-
nus above, the Adductor brevis below; the Gracilis along its inner border, the
Compressor nrethrse towards its internal aspect ; and a portion of the Obturator
externus where it enters into the formation of the foramen of that name. Its
inner surface is smooth. Its inner border is thick, rough, and everted, especially
250
THE SKELETON.
iu females. In tlie male it serves for the attacliment of tlie cms penis. Its
outer horder forms part of tlie circumference of tlie obturator foramen.
Tlie cotyloid cavity^ or acetahulum^ is a deep, cup-shaped, hemispherical depres-
sion ; formed, internally, bj the pubes, above by the ilium, behind and below
by the ischium ; a little less than two-fifths being formed by the ilium, a little
more than two-fifths by the ischium, and the remaining fifth by the pubes. It
is bounded by a prominent uneven rim, which is thick and strong above, and
serves for the attachment of a fibro-cartilaginous structure which contracts its
orifice, and deepens the surface for articulation. It presents on its inner side a
deep notch, the cotyloid notch, which transmits the nutrient vessels into the
interior of the joint, and is continuous with a circular depression at the bottom
of the cavity : this depression is perforated by numerous apertures, lodges a
mass of fat, and its margins serve for the attachment of the ligamentum teres.
The notch is converted, in the natural state, into a foramen by a dense ligamen-
tous band which passes across it. Tlirougli this foramen the nutrient vessels
and nerves enter the joint.
Fig. 192.— Plan of the Development of the Os Inn:minatum.
i-> o yr , I '^■CrimcirylJlitini'.I-icJdum.k.I^ivics
The 'i Trima/ry ee/nlris unite ihrouc/h Y sSluhtd fiicre jalnnijMlcvijl
Jl'^i^hyscs ajTpcar ahoict pulerty , ^ u-nCtc uiout 26':'/ year
The ohturntor or thyroid, fornmen is a large aperture, situated between the
ischium and ])ubos. In the male it is large, of an oval form, its longest diameter
being obliqiK'Ty from above doAvnwards; in the female it is smaller, and more
triangular. It is bounded by a thin uneven margin, to which a strong mcm-
brano is attached ; and presents, at its u))i)(U' and onlcr part, a deep groove,
which runs frr)iii Ww ptOvis oblirpioly forwards, inwiir<ls, and (^()wn^\'ards. This
groove is convert cil inlo it foi'iiincii b\' iIk^ obturator mcinltraue, and Iraiisniils
the obturator vessels and nerve.
HirvoiiiTo. This bone consists of nincli ('anccllons tissue, es])0('ially whore it
is thick, iriclDsed bctM^ecn two layers of dense compact tissue. In tlie tliiiuier
PELVIS. 251
parts of tlie bone, as at tlie bottom of tlie acetabulum and centre of the iliac
fossa, it is usually semi-transparent, and composed entirely of compact tissue.
Bevelojwient (Fig. 192). By eic/ht centres : tliree primary — one for the ilium,
one for the ischium, and one for the pubes ; and five secondary — one for the crest
of the ilium its whole length, one for the anterior inferior spinous process (said
to occur more frequently in the male than the female), one for the tuberosity of
the ischium, one for the symphysis pubis (more frequent in the female than the
male), and one for the Y-shaped piece at the bottom of the acetabulum. These
various centres appear in the following order : First, in the ilium, at the lower
part of the bone, immediately above the sciatic notch, at about the same period
that the development of the vertebrjB commences. Secondly, in the body of the
ischium, at about the third month of foetal life. Thirdly, in the body of the
pubes, between the fourth and fifth months. At birth, the three primary cen-
tres are quite separate, the crest, the bottom of the acetabulum, and the rami of
the ischium and pubes, being still cartilaginous. At about the sixth year, the
rami of the pubes and ischium are almost completely ossified. About the thir-
teenth or fourteenth year, the three divisions of the bone have extended their
growth into the bottom of the acetabulum, being separated from each other by
a Y-shaped portion of cartilage, which now presents traces of ossification. The
ilium and ischium then become joined, and lastly the pubes, through the inter-
vention of this Y-shaped portion. At about the age of puberty, ossification
takes place in each of the remaining portions, and they become joined to the
rest of the bone about the twenty-fifth year.
Articulations. With its fellow of the opposite side, the sacrum and femur.
Attachment of Muscles. Ilium. To the outer lip of the crest, the Tensor vaginee
femoris, Obliquus externus abdominis, and Latissimus dorsi ; to the internal lip,
the Transversalis, Quadratus lumborum, and Erector spince; to the interspace
between the lips, the Obliquus internus. To the outer surface of the ilium, the
Gluteus maximus. Gluteus medius, Gluteus minimus, reflected tendon of Rectus,
portion of Pyriformis ; to the internal surface, the Iliacus, and the Multifidus
spinee to the internal surface of the posterior superior spine ; to the anterior border,
the Sartorius and straight tendon of the rectus. Ischium. To its outer surface,
the Obturator externus; internal surface. Obturator internus and Levator ani.
To the spine, the Gemellus superior, Levator ani, and Coccygeus. To the
tuberosity, the Biceps, Semi-tendinosus, Semi-membranosus, Quadratus femoris.
Adductor magnus. Gemellus inferior, Transversus perinasi. Erector penis. To
the Puhes, the Obliquus externus, Obliquus internus, Transversalis, Rectus,
Pyramidalis, Psoas parvus, Pectineus, Adductor longus, Adductor brevis, Gra-
cilis, Obturator externus and internus, Levator ani. Compressor urethree, and
occasionally a few fibres of the Accelerator urinee.
The Pelvis (Figs. 193, 194).
The Pelvis, so called from its resemblance to a basin, is stronger and more
massively constructed than either the cranial or thoracic cavity ; it is a bony ring
interposed between the lower end of the spine, which it supports, and the lower
extremities, upon which it rests. It is composed of four bones : the two ossa
innominata, which bound it on either side and in front; and the sacrum and
coccyx, which complete it behind.
The pelvis is divided by a prominent line, the linea ilio-pectinea, into the false
and true pelvis.
The false pelvis is all that expanded portion of the pelvic cavity which is
situated above the linea ilio-pectinea. It is bounded on each side by the ossa ilii ;
in front it is incomplete, presenting a wide interval between the spinous processes
of the ilia on either side, which is filled up in the recent state by the parietes of
the abdomen ; behind, in the middle line, is a deep notch. This broad shallow
252
THE SKELETON.
cavity is fitted to support the intestines, and to transmit part of tlieir weight to
the anterior wall of the abdomen.
The true pelvis is all that part of the pelvic cavity which is situated beneath
the linea ilio-pectinea. It is smaller than the false pelvis, but its walls are more
perfect. For convenience of description, it is divided into a superior circum-
ference or inlet, an inferior circumference or outlet, and a cavity.
Fig. 193.— Male Pelvis (Adult).
Fig. 194. Female Pelvis (Adult).
Tlio .Hiiperior circumferenrf fnnns the inar^.'-iii of lii-'nn of the ytolvis, the included
Kpaxjc bci)ig called the inlr't. It is formed bv tlic bncailio-pecliiica, com])lctcd in
front by tlie spine and crest of the pub(>s, and behind by the anterior margin of
the base of the sacrum and sacro-vertebral angle.
PELVIS.
253
Tlie inlet of tlie pelvis is somewliat heart- shaped, obtusely pointed in front,
diverging on either side, and encroached upon behind by the projection forwards
of the promontory of the sacrum. It has three principal diameters-, antero-
posterior (sacro-pubic), transverse, and oblique. The antero-posterior extends
from the sacro-vertebral angle to the symphysis pubis ; its average measurement
is four inches. The transverse extends across the greatest width of the inlet, from
the middle of the brim on one side to the same point on the opposite ; its average
measurement is five inches. The oblique extends from the margin of the pelvis,
corresponding to the ilio-pectineal eminence on one side, to the sacro-iliac sym-
physis on the opposite side ; its average measurement is also five inches.
The cavity of the true pelvis is bounded in front by the symphysis pubis ;
behind by the concavity of the sacrum and coccyx, which, curving forwards
above and below, contracts the inlet and outlet of the canal ; and laterally it is
bounded by a broad, smooth, quadrangular plate of bone, corresponding to the
inner surface of the body of the ischium. The cavity is shallow in front, mea-
suring at the symphysis an inch and a half in depth, three inches and a half in
the middle, and four inches and a half posteriorly. From this description, it will
be seen that the cavity ol the pelvis is a short curved canal, considerably deeper
on its posterior than on its anterior wall, and broader in the middle than at either
extremity, from the projection forwards of the sacro-coccygeal column above
and below. This cavity contains, in the recent subject, the rectum, bladder, and
part of the organs of generation. The rectum is placed at the back of the pelvis,
and corresponds to the curve of the sacro-coccygeal column ; the bladder in front,
behind the symphysis pubis. In the female, the uterus and vagina occupy the
interval between these parts.
The lower circumference of the pelvis is very irregular, and forms what is
called the outlet. It is bounded by three prominent eminences : one posterior,
formed by the point of the coccyx ; and one on each side, the tuberosities of the
ischia. These eminences are separated by three notches: one in front, the
puhic arch, formed by the convergence of the rami of the ischia and pubes on
each side. The other notches, one on each side, are formed by the sacrum and
coccyx behind, the ischium in front, and the ilium above ; they are called the
sacro-sciatic notches ; in the natural
state they are converted into foramina
by the lesser and greater sacro-sciatic
ligaments.
The diameters of the outlet of the
pelvis are two, antero-posterior and
transverse. The antero-posterior ex-
tends from the tip of the coccyx to
the lower part of the symphysis pubis,
and the transverse from the posterior
part of one ischiatic tuberosity to the
same point on the opposite side : the
average measurement of both is four
inches. The antero-posterior dia-
meter varies with the length of the
coccyx, and is capable of increase or
diminution, on account of the mobility
of that bone.
Position of the Pelvis. In the erect
posture, the pelvis is placed obliquely
with regard to the trunk of the body :
the pelvic surface of the symphysis
pubis looking upwards and backwards, the concavity of the sacrum and coccyx
looking downwards and forwards ; the base of the sacrum in well-formed female
bodies being nearly four inches above the upper border of the symphysis pubis,
Fig. 195. — Tertical Section of the Pelvis, with
lines iiidicatin"' the Axes of the Pelvis.
FUne
,f OutU^
254 THE SKELETON.
and the apex of tlie coccyx a little more tlian half an inch above its lower border.
The obliquity is much greater in the foetus, and at an early period of life, than
in the adult.
Axes of the Pelvis (Fig. 195). The plane of the inlet of the true pelvis will
be represented by a line drawn from tlie base of the sacrum to the upper margin
of the symphysis pubis. A line carried at right angles with this at its middle,
would correspond at one extremity with the umbilicus, and at the other with
the middle of the coccyx ; the axis of the inlet is therefore directed downwards
and backwards. The axis of the outlet produced upwards would touch the
base of the sacrum, and is therefore directed downwards and forwards. The
axis of the cavity is curved like the cavity itself: this curve corresponds to the
concavity of the sacrum and coccyx, the extremities being indicated by the
central points of the inlet and outlet. A knowledge of the direction of these
axes serves to explain the course of the foetus in its passage through the pelvis
during parturition. It is also important to the surgeon, as indicating the direc-
tion of the force required in the removal of calculi from the bladder, and as
determining the direction in which instruments should be used in operations
upon the pelvic viscera.
Differences hetiveen the Male and Female Pelvis. In the male the bones are
thicker and stronger, and the muscular eminences and impressions on their
surfaces more strongly marked. The male pelvis is altogether more massive ;
its cavity is deeper and narrower, and the obturator foramina of larger size. In
ihe female the bones are lighter and more expanded, the muscular impressions
on their surfaces are only slightly marked, and the pelvis generally is less mas-
sive in structure. The iliac fossae are broad, and the spines of the ilia widely
separated ; hence the great prominence of the hips. The inlet and the outlet
are larger ; the cavity is more capacious, and the spines of the ischia project ■
less into it. The promontory is less projecting, the sacrum wider and less
curved,^ and the coccyx more movable. The arch of the pubes is wider, and
its edo-es more everted. The tuberosities of the ischia and the acetabula are
wider apart.
In the foetus and for several years after birth, the pelvis is small in proportion
to that of the adult. The cavity is deep, and the projection of the sacro- verte-
bral angle less marked. The antero-posterior and transverse diameters are
nearly equal. About puberty^ the pelvis in both sexes presents the general
characters of the adult male pelvis, but after puberty it acquires its proper
sexual characters.
The Femur or Thigii-boke.
The Femur is the longest, largest, and strongest bone in the skeleton, and
almost perfectly cylindrical in the greater part of its extent. In the erect pos-
ture it is not vertical, being separated from its fellow above by a considerable
interval, which corresj^onds to the entire breadth of the pelvis, but inclining
gradually downwards and inwards, so as to approach its fellow towards its lower
])art, for the purpose of bringing the knee-joint near the line of gravity of the
body. The degree of this inclination varies in different persons, and is greater
in the female than in the male, on account of the greater breadth of the pelvis.
The femur, like other long bones, is divisible into a shaft, and two extremities.
The Upper Extremity presents for examination a head, a neck, and the
greater and lesser trochanters.
The head^ which is globular, and forms rather more than a hemisphere, is
directed u])wards, inwards, nnd a little forwards, the greater ]oart of its convexity
being above and in front. lis snrf'ace is sniootli, coaled with cartilage in the
' Tt is not luinsuiil. lidwcvcr. In find lln' siicrum in tlic foiimle presciuing a considerable cnrvo
e.xtciidinf^ tlironfilidut its wIkiIc li'iin'tli.
FEMUR.
255
recent state, and presents, a
little beliind and below its
centre, an ovoid depression,
for the attacliment of the
ligamentum teres. The neck
is a flattened pyramidal pro-
cess of bone, which connects
the head with the shaft. It
varies in length and obliquity
at various periods of life, and
under different circumstances.
Before puberty it is directed
obliquely, so as to form a
gentle curve from the axis of
the shaft. In the adult male
it forms an obtuse angle with
the shaft, being directed up-
wards, inwards, and a little
forwards. In the female it
approaches more nearly a
right angle. Occasionally, in
very old subjects, and more
especially in those greatly
debilitated, its direction be-
comes horizontal; so that the
head sinks below the level of
the trochanter, and its length
diminishes to such a degi'ee,
that the head becomes almost
contiguous with the shaft.
The neck is flattened from be-
fore backwards, contracted in
the middle, and broader at its
outer extremity, where it is
connected with the shaft, than
at its summit, where it is
attached to the head. It is
much broader in the vertical
than in the antero- posterior
diameter, and much thicker
below than above, on account
of the greater amount of re-
sistance required in sustain-
ing the weight of the trunk.
The anterior surface of the
neck is perforated by nume-
rous vascular foramina. The
posterior surface is smooth,
and is broader and more con-
cave than the anterior ; it
receives towards its outer
side the attachment of the
capsular ligament of the hip.
The superior border is short
and thick, bounded exter-
nally by the great trochanter,
and its surface perforated by
large foramina. The inferior
Fig. 196. — Eight Feirrnr. Anterior Surface.
OHTUBHTCIR INTERNUS fc O-MCHi
PVair-OflMia
UlCAMENTUM'TEf!!
"'"lyh
256 THE SlvELETON.
border^ long and narrow, curves a little backwards, to terminate at tlie lesser
trochanter.
The Trochanters {tpoxd^^ to run or roll) are prominent processes of bone which
afford leverage to the muscles which rotate the thigh on its axis. Thej are
two in number, the greater and the lesser.
The Great Trochanter is a large irregular quadrilateral eminence, situated at
the outer side of the neck, at its junction with the upper part of the shaft. It
is directed a little outwards and backwards, and, in the adult, is about three-
quarters of an inch lower than the head. It presents for examination two
surfaces, and four borders. The external surface^ quadrilateral in form, is broad,
rough, convex, and marked by a prominent diagonal line, which extends from
the posterior superior to the anterior inferior angle : this line serves for the
attachment of the tendon of the Gluteus medius. Above the line is a triangular
surface, sometimes rough for part of the tendon of the same muscle, sometimes
smooth for the interposition of a bursa between that tendon and the bone.
Below and behind the diagonal line is a smooth triangular surface over which
the tendon of the Gluteus maximus muscle plays, a bursa being interposed.
The iyiteymal surface is of much less extent than the external, and presents at
its base a deep depression, the digital or trochanteric fossa, for the attachment
of the tendon of the Obturator externus muscle. The superior border is free ;
it is thick and irregular, and marked by impressions for the attachment of the
Pyriformis behind, the Obturator internus and Gemelli in front. The inferior
border corresponds to the point of junction of the base of the trochanter with
the outer surface of the shaft ; it is rough, prominent, slightly curved, and gives
attachment to the upper part of the Vastus externus muscle. The anterior
border is prominent, somewhat irregular, as well as the surface of bone imme-
diately below it; it affords attachment by its outer part to the Gluteus minimus.
The 'posterior border is very prominent, and appears as a free rounded edge,
which forms the back part of the digital fossa.
The Lesser Trochanter is a conical eminence, which varies in size in different
subjects ; it projects from the lower and back part of the base of the neck. Its
base is triangular, and connected with the adjacent parts of the bone by three
well-marked borders : two of these are above — the irdernal continuous with the
lower border of the neck ; the external with the posterior intertrochanteric line,
while the inferior border is continuous with the middle division of the linea
aspera. Its summit, which is directed inwards and backwards, is rough, and
gives insertion to the tendon of the Psoas magnus. The Iliacus is inserted into
the shaft below the lesser trochanter, between the Vastus internus in front, and
the Pectineus behind. A well-marked prominence, of variable size, which pro-
jects from the upper and front part of the neck, at its junction with the great
trochanter, is called the tubercle of the femur ; it is the point of meeting of five
muscles, the Gluteus mimimus externally, the Vastus externus below, and the
tendon of the Obturator internus and Gemelli above. Kunning obliquel}^ down-
wards and inwards from the tubercle is the spiral line of the femur, or anterior
intertrochanteric line ; it winds round the inner side of the shaft, below the
lesser trochanter, and terminates in the linea aspera, about two inches below this
eminence. Its upper half is rough, and affords attachment to the capsular liga-
ment of the hip joint ; its lower half is less prominent, and gives attachment to
the upper part of the Vastus internus. The posterior intertrochanteric line is very
prominent, ;ind runs from the summit of the great trochanter downwards and
inwards to 1 lie upper and back part of llic lesser trochanter. Its upper half
forms the p(;sterJor border of the great trQchanter A Avcll-marked eminence
(commences about the middle of the posterior inteiirfichantci'ic line, and passes
vertically downwards for about two inches along the back jiai't of the shaft: it
is called the linea (pi.wlrati^ and gives attachment to the Quadratus femoris, and
a few fibres of the Adductor magnus muscles.
The Hhdft, almost perfectly cylindrical in form, is a little broader above than
FEMUR.
257
in tlie centre, and somewhat
flattened from before backwards
below. It is slightly arched,
so as to be convex in front ;
concave behind, where it is
strengthened by a prominent
longitudinal ridge, the linea
aspera. It presents for exami-
nation three borders separating
three surfaces. Of the three
borders, one, the linea aspera,
is posterior; the other two are
placed laterally.
The linea aspera (Fig. 197) is
a prominent longitudinal ridge
or crest, presenting, on the mid-
dle third of the bone, an ex-
ternal lip, an internal lip, and a
rough intermediate space. A
little above the centre of the
shaft, this crest divides into
three lines •} the most external
one becomes very rough, and is
continued almost vertically up-
wards to the base of the great
trochanter ; the middle one, the
least distinct, is continued to the
base of the trochanter minor ;
and the internal one is lost above
in the spiral line of the femur.
Below, the linea aspera divides
into two bifurcations, which in-
close between them a triangular
space (the popliteal space), upon
which rests the popliteal artery.
Of these two bifurcations, the
outer branch is the more promi-
nent, and descends to the sum-
mit of the outer condyle. The
inner branch is less marked,
presents a broad and shallow
groove for the passage of the
femoral artery, and terminates
in a small tubercle at the sum-
mit of the internal condyle.
To the inner lip of the linea
aspera, along its whole length,
is attached the Vastus internus ;
and to the whole length of the
outer lip, the Vastus externus.
The Adductor magnus is also
attached to the whole length of
the linea aspera, being connected
with the outer lip above, and the
' Of these three lines, only the oiiter
and inner are described by many annto-
mists : the linea aspera is then said to
bifurcate above and below.
17
Fig.
197. — Right Femur.
Suri'ace.
-t osterior
■. /"arte
Art''
258 THE SKELETON.
inner lip below. Between tlie Yastns externus and the Adductor magnus are
attached two muscles, viz., the Gluteus maximus above, and the short head of
the Biceps below. Between the Adductor magnus and the Vastus internus four
muscles are attached : the Iliacus and Pectineus above (the latter to the middle
of the upper divisions) ; below these, the Adductor brevis and Adductor longus.
The linea aspera is perforated a little below its centre by the nutrient canal,
which is directed obliquely upwards.
The two lateral borders of the femur are only slightly marked, the outer one
extending from the anterior inferior angle of the great trochanter to the anterior
extremity of the external condyle ; the inner one from the spiral line, at a point
opposite the trochanter minor, to the anterior extremity of the internal condyle.
The internal border marks the limit of attachment of the Crureus muscle inter-
nally.
The anterior surface includes that portion of the shaft which is situated be-
tween the two lateral borders. It is smooth, convex, broader above and below
than in the centre, slightly twisted, so that its upper part is directed forwards
and a little outwards, its lower part forwards and a little inwards. To the upper
three-fourths of this surface the Crureus is attached ; the lower fourth is sepa-
rated from the muscle by the intervention of the S3movial membrane of the
knee-joint, and aftbrds attachment to the Subcrureus to a small extent. The
external surface includes the portion of bone between the external border and
the outer lip of the linea aspera ; it is continuous above with the outer surface
of the great trochanter ; below with the outer surface of the external condyle :
to its upper three-fourths is attached the outer portion of the Crureus muscle.
The internal surface includes the portion of bone between the internal border
and the inner lip of the linea aspera ; it is continuous, above, with the lower
border of the neck ; below, with the inner side of the internal condyle : it is
covered by the Vastus internus muscle.
The Lower Extremity^ larger than the upper, is of a cuboid form, flattened
from before backwards, and divided into two large eminences, the condyles
(zoi'SvTioj, a knuckle)^ by an interval which presents a smooth depression in front
called the trochela, and a notch of considerable size behind — the interconclyloid
notch. The external condyle is the more prominent anteriorly, and is the broader
both in the antero-posterior and transverse diameters. The internal condyle is
the narrower, longer, and more prominent internally. This difference in the
length of the two condyles is only observed when the bone is perpendicular,
and depends upon the obliquity of the thigh-bones, in consequence of their
separation above at the articulation with the pelvis. If the femur is held ob-
liquely, the surfaces of the two condyles will be seen to be nearly horizontal.
The two condyles are directly continuous in front, and form a smooth, trochlear
surface, the external border of which is more prominent, and ascends higher
than the internal one. This surface articulates with the patella. It presents a
median groove, which extends downwards and baclcAvards to the intercondyloid
notch ; and two lateral convexities, of which the external is the broader, more
prominent, and prolonged further upwards upon the front of the outer condyle.
The intercondyloid notch lodges the crucial ligaments ; it is bounded laterally
by the opposed surfaces of the two condyles, and in front by the lower end of
the shaft.
Outer Condyle. Tlie outer surface of the external condyle presents, a little
behind ils centre, an eminence, the outer tuherosity ; it is less prominent than
the inner tuberosity, and gives attachment to the external lateral ligament of
the knee. Tm mediately beneath it, is a groove which commences at a depreS'
sion a little behind the centre of the lower border of this surface: the depres-
sion is for tlir, iciidon of origin of the Po])liteus muscle; the groove in which
this tendon is f/mlained is smooth, covered with cartilngc in the recent state,
and runs upwards and backwards to tlie posterior extremity of the condyle.
The inner surface of the outer condyle Ibrms one of the latci'al Ijoundarics of
FEMUR.
259
Fig. 198. — Diagram showing the Structure
of the Neck of the femur. (Ward.)
the intercondyloid notcli, and gives attachment, by its posterior part, to the
anterior crucial ligament. The inferior surface is convex, smooth, and broader
than that of the internal condyle. The posterior extremity is convex and
smooth : just above the articular surface is a depression for the tendon of the
outer head of the Gastrocnemius, above which is the origin of the Plantaris.
Inner Condyle. The inner surface of the inner condjde presents a convex
eminence, the inner tuberosity^ rough, for the attachment of the internal lateral
ligament. Above this tuberosity, at the termination of the inner bifurcation of
the linea aspera, is a tubercle, for the insertion of the tendon of the Adductor
magnus ; and behind and beneath the tubercle a depression for the tendon of the
ianer head of the Gastrocnemius. The outer side of the inner condyle forms
one of the lateral boundaries of the intercondyloid notch, and gives attachment,
by its anterior part, to the posterior crucial ligament. Its inferior or articular
surface is convex, and presents a less extensive surface than the external condyle.
Structure. The shajpt of the femur is a cylinder of compact tissue, hollowed
by a large medullary canal. The cylinder is of great thickness and density in
the middle third of the shaft, where the bone is narrowest, and the medullary
canal well formed ; but above and .below this, the cylinder gradually becomes
thinner, owing to a separation of the layers of the bone into cancelli, which pro-
ject into the medullary canal and finally
obliterate it, so that the ujiper and lower
ends of the shaft, and the articular ex-
tremities more especially, consist of can-
cellated tissue, invested by a thin compact
layer. -
The arrangement of the cancelli in the
ends of the femur is remarkable. In the
upper end (Fig. 198), they run in parallel
columns a a from the summit of the head
to the thick under wall of the neck, while
a series of transverse fibres h b cross the
parallel columns, and connect them to
the thin upper wall of the neck. Another
series of plates c c springs from the whole
interior of the cylinder above the lesser
trochanter ; these pass upwards and con-
verge to form a series of arches beneath
the upper wall of the neck, near its junction with the great trochanter. This
structure is admirably adapted to sustain, with the greatest mechanical advan-
tage, concussion or weight transmitted from above, and serves an important
office in strengthening a part especially liable to fracture.
In the lower end, the cancelli spring on all sides from the inner surface of the
cylinder, and descend in a perpendicular direction to the articular surface, the
cancelli being strongest and having a more accurately perpendicular course
above the condyles.
Articulations. With three bones : the os innominatum, tibia, and patella.
Development (Fig. 199). The femur is developed \>j five centres: one for the
shaft, one for each extremity, and one for each trochanter. Of all the long
bones, except the clavicle, it is the first to show traces of ossification ; this com-
mences in the shaft, at about the fifth week of foetal life, the centres of ossifica-
tion in the epiphyses appearing in the following order : First, in the lower end
of the bone, at the ninth month of foetal life ; from this the condyles and tube-
rosities are formed ; in the head, at the end of the first year after birth ; in the
great trochanter, during the fourth year ; and in the lesser trochanter, between
the thirteenth and fourteenth. The order in which the epiphyses are joined to
the shaft, is the reverse of that of their appearance ; their junction does not
commence until after puberty, the lesser trochanter being first joined, then the
260
THE SKELETON.
greater, tlien tlie head, and, lastly, tlie inferior extremity (tlie first in wliicK
ossification commenced), "vvliicli is not united until the twentieth year.
Attachment of Muscles. To the great trochanter : the Gluteus medius, Gluteus
minimus, Pyriformis, Obturator internus. Obturator externus. Gemellus superior.
Gemellus inferior, and Quadratus femoris. To the lesser trochanter : the Psoas
magnus, and the Iliacus below it. To the shaft, its posterior surface : the Vas-
tus externus, Gluteus maximus, short head of the Biceps, Vastus internus. Ad-
ductor magnus, Pectineus, Adductor brevis, and Adductor longus ; to its anterior
surface, the Crureus and Subcrureus. To the condjdes : the Gastrocnemius,
Plantaris, and Popliteus.
Fig. 199. — Plan of the Development of tlie
Femur. By Five Centn-'S.
Appears at 0t/r z^].
affvear.f at y-7no
Avffarii rittnd'J't.y^
'joiasShaft alaut iS'.'-if'
^3 Joins S/irtJi aiiout m'? yt
Jovyis Sha:j-lat?J)'\f.
Fig. 200.— Right Patella.
Anterior iSurface.
Fig. 201.— Posterior
Surface.
'''^z- Lxirefi^'^^'^
THE LEG.
The skeleton of the Leg consists of three bones: the Patella, a large sesamoid
hone, placed in front of the knee; and the Tibia, and Fibula.
The Patella. (Figs. 200, 20L)
The Patella is a flat, triangular bone, situated at the anterior part of the knee-
Joint. It resembles the sesamoid bones, from being, developed in the tendon of
the Quadriceps extensor, and in its structure, being composed throughout of
dense cancellous tissue; but it is generally rcga^'ded as analogous to the olecra-
non process of the ulna, which occasionally exists as a sc]-)aratc piece, connected
1() the shaft of the bone by a continual ion'of the tendon of tlie Triceps muscle.^
' Professor Owen states, tliat, "in rertain l):\1s. there is a development of a sesamoid 1)one in
tlie Ijieeps brachii, whicli is IIh; trnc liomotypc of tlie patella in the leg," regarding tlie olecranon
a-: homoloirons, not witli tlie palella, but w'ilh an extension of the upper end of Ihe filjula above'
the knee-joint, which is met with in some aniiinls. [On /Iw Ncdurc <f L/'inhs, pp. 19, 24.)
PATELLA.
261
It serves to protect the front of
the joint, and increases the
leverage of the Quadriceps ex-
tensor by making it act at a
greater angle. It presents an
anterior and posterior surface,
three borders, a base, and an
apex.
The anterior surface is convex,
perforated by small apertures,
for the passage of nutrient ves-
sels, and marked by numerous
rough longitudinal striae. This
surface is covered, in the recent
state, by an expansion from the
tendon of the Quadriceps exten-
sor, and separated from the in-
tegument by a bursa. It gives
attachment below to the liga-
mentum patella. The posterior
surface presents a smooth, oval-
shaped, articular surface, cov-
ered with cartilaa;e in the recent
state, and divided into two facets
by a vertical ridge, which de- -
scends from the superior towards
the inferior angle of the bone.
The ridge corresponds to the
groove on the trochlear surface
of the femur, and the two facets
to the articular surfaces of the
two condyles ; the outer facet,
for articulation with the outer
condyle, being the broader and
deeper. This character serves
to indicate the side to which the
bone belongs. Below the ar-
ticular surface is a rough, con-
vex, non-articular depression,
the lower half of which gives
attachment to the ligamentum
patella; the' upper half being
separated from the head of the
tibia by adipose tissue.
The superior and lateral bor-
ders give attachment to the ten-
don of the Quadriceps extensor ;
the superior border^ to that por-
tion of the tendon which is
derived from the Rectus and
Crureus muscles; and the latercCl
borders, to the portion derived
from the external and internal
Vasti muscles.
The base, or superior border, is
Fig. 202.
SttflclH jiyoct
-Bones of the Right Leg. Anterior Surface.
H e a. ^
t>-r,^A MalL«h.,
Urtfyaini HiTallentus
262
THE SKELETON.
Fia-.
203. — Boues of the Right Leg. Posterior Surface.
tliick, directed upwards, and cut
obliquely at the expense of its
outer surface; it receives the
attachment, as already men-
tioned, of part of the Quadriceps
extensor tendon.
The apex is pointed, and gives
attachment to the ligamentum
patella.
Structure. It consists of dense
cancellous tissue, covered by a
thin compact lamina.
Development. By a single
centre, which makes its appear-
ance, according to Beclard, about
the third year. In two instances,
I have seen this bone cartilagi-
nous throughout, at a much later
period (six years). More rarely,
the bone is developed by two
centres, placed side by side.
Articulations. With the two
condyles of the femur.
Attachment of Muscles. The
Rectus, Crureus, Vastus inter-
nus, and Vastus externus. These
muscles joined at their insertion
constitute the Quadriceps exten-
sor cruris.
The Tibia. (Figs. 202, 203.)
The Tibia is situated at the
front and inner side of the leg,
and, excepting the femur, is the
longest and largest bone in the
skeleton. It is prism oid in
form, expanded above, where it
enters into the knee-joint, more
slightly enlarged below. In the
male, its direction is vertical, and
parallel with the bone of the
opposite side; but in the female
it has a slight oblique direction
downwards and outwards, to
compensate for the oblique di-
rection of the femur inwards.
It ]~»rcscnts for examination a
shaft and two extremities.
IMic Upper ExtremAty.^ or head,
is large and expanded on each
side into two lateral eminences,
the tuberosities. Superiorly, the
tuberosities i)resent two smooth
concave surfaces, which articulate with the condyles of the femur; the internal
articular surface is longer than the external, and oval from before backwards,
TIBIA. 263
to articulate witli the internal condyle ; the external one being broader, flatter,
and more circular, to articulate with the external condyle. Between the two
articular surfaces, and nearer the posterior than the anterior aspect of the bone,
is an eminence, the spinous process of the tibia, surmounted by a prominent
tubercle on each side, which gives attachment to the extremities of the semi-
lunar fibro-cartilages; in front and behind the spinous process is a rough depres-
sion for the attachment of the anterior and posterior crucial ligaments and the
semilunar cartilages. The anterior surfaces of the tuberosities are continuous
with one another, forming a single large surface, which is somewhat flattened :
it is triangular, broad above, and perforated by large vascular foramina, narrow
below, where it terminates in a prominent oblong elevation of large size, the
tubercle of the tibia ; the lower half of this tubercle is rough, for the attachment
of the ligamentum patellee ; the upper half is a smooth facet corresponding, in
the recent state, with a bursa which separates the ligament from the bone.
Posteriorly, the tuberosities are separated from each other by a shallow depres-
sion, the popliteal notch, which gives attachment to the posterior crucial liga-
ment. The posterior surface of the inner tuberosity presents a deep transverse
groove, for the insertion of the tendon of the Semimembranosiis ; and the poste-
rior surface of the outer one, a flat articular facet, nearly circular in form,
directed downwards, backwards, and outwards, for articulation with the fibula.
The lateral surfaces are convex and rough : the internal one, the most promi-
nent, gives attachment to the internal lateral ligament.
The Shaft of the tibia is of a triangular prismoid form, broad above, gradually
decreasing in size to the commencement of its lower fourth, its most slender part
where fracture most frequently occurs ; it then enlarges again towards its lower
extremity. It presents for examination three surfaces and three borders.
The anterior border^ the most prominent of the three, is called the crest of the
tibia, or, in popular language, the shin; it commences above at the tubercle,
and terminates below at the anterior margin of the inner malleolus. This bor-
der is very prominent in the upper two-thirds of its extent, smooth and rounded
below. It presents a very flexuous course, being curved outwards above, and
inwards below; it gives attachment to the deep fascia of the leg.
The internal border is smooth and rounded above and below, but more promi-
nent in the centre; it commences at the back part of the inner tuberosity, and
terminates at the posterior border of the internal malleolus ; its upper part gives
attachment to the internal lateral ligament of the knee to the extent of about
two inches, and to some fibres of the Popliteus muscle ; its middle third, to some
fibres of the Soleus and Flexor longus digitorum muscles.
The external border, or interosseous ridge, is thin and prominent, especially its
central part, and gives attachment to the interosseous membrane ; it commences
above in front of the fibular articular facet, and bifurcates below, to form the
boundaries of a triangular rough surface, for the attachment of the interosseous
ligament connecting the tibia and fibula.
The internal surface is smooth, convex, and broader above than below; its
upper third, directed forwards and inwards, is covered by the aponeurosis derived
from the tendon of the Sartorius, and by the tendons of the Gracilis and Semi-
tendinosus, all of which are inserted nearly as far forwards as the anterior border;
in the rest of its extent it is subcutaneous.
The external surface is narrower than the internal ; its upper two-thirds present
a shallow groove for the attachment of the Tibialis anticus muscle ; its lower
third is smooth, convex, curves gradually forwards to the anterior part of the
bone, and is covered from within outwards by the tendons of the following
muscles : Tibialis anticus. Extensor proprius pollicis. Extensor longus digitorum,
Peroneus tertius.
^\\Q posterior surface (Fig. 203) presents, at its upper part, a prominent ridge,
the oblique line of the tibia, which extends from the back part of the articular
facet for the fibula, obliquely doAvnwards, to the internal border, at the junction
264 THE SKELETON.
of its upper and middle tliirds. It marks tlie limit for the insertion of the Pop-
liteus muscle, and serves for the attachment of the popliteal fascia, and part of
the Soleus, Flexor longus digitorum, and Tibialis posticus muscles ; the tri-
angular concave surface, above and to the iinier side of this line, gives attach-
ment to the Popliteus muscle. The middle third of the posterior surface is
divided by a vertical ridge into two lateral halves : the ridge is well marked at its
commencement at the oblique line, but becomes gradually indistinct below : the
inner and broader half gives attachment to the Flexor longus digitorum, the outer
and narrower to part of the Tibialis posticus. The remaining part of the bone is
covered by the Tibialis posticus, Flexor longus digitorum, and Flexor longus
pollicis muscles. Immediately below the oblique line is the medullary foramen,
which is directed obliquely downwards.
The Loiver Extremity^ much smaller than the upper, presents five surfaces ; it
is prolonged downwards, on its inner side, into a strong process, the internal
malleolus. The inferior surface of the bone is quadrilateral, and smooth, for
articulation with the astragalus. This surface is narrow internally, where it
becomes continuous with the articular surface of the inner malleolus, broader
externally, and traversed from before backwards by a slight elevation, separating
two lateral depressions. The anterior surface of the lower extremity is smooth
and rounded above, and covered by the tendons of the Extensor muscles of the
toes ; its lower margin presents a rough transverse depression, for the attachment
of the anterior ligament of the ankle-joint : the j^osterior surface presents a super-
ficial groove directed obliquely downwards and inwards, continuous with a similar
groove on the posterior extremity of the astragalus, and serving for the passage
of the tendon of the Flexor longus pollicis : the external surface presents a tri-
angular rough depression for the attachment of the inferior interosseous ligament
connecting it with the fibula; the lower part of this depression is smooth in some-
bones, covered with cartilage in the recent state, and articulating with the fibula.
This surface is bounded by two prominent ridges, continuous above with the
interosseous ridge : they afford attachment to the anterior and posterior tibio-
fibular ligaments. The internal surface of the lower extremity is prolonged
downwards to form a strong pyramidal process, flattened from without inwards,
the inner malleolus. The inner surface of this process is convex and subcuta-
neous ; its outer surface^ smooth and slightly concave, deepens the articular sur-
face for the astragalus ; its anterior border is rough, for the attachment of liga-
mentous fibres ; its posterior horder presents a broad and deep groove, directed
obliquely downwards and inwards, which is occasionally double : this groove
transmits the tendons of the Tibialis posticus and Flexor longus digitorum
muscles. The summit of the internal malleolus is marked by a rough depression
behind, for the attachment of the internal lateral ligament of the ankle-joint.
Structure. Like that of the other long bones.
Development. By three centres (Fig. 204): one for the shaft, and one for each
extremity. Ossification commences in the centre of the shaft about the same
time as in the femur, the fifth week, and gradually extends towards either
extremity. The centre for the upper epiphysis appears at birth ; it is flattened
in form, and has a thin tongue-shaped process in front, which forms the tubercle.
That for the lower epiphysis appears in the second year. The lower epiphysis
joins the shaft at about the twentieth year, and the upper one about the twenty-
fifth year. Two additional centres occasionally exist, one for the tongue-shaped
process of the upper epiphysis, the tubercle, and one for the inner malleolus.
AriicuJxiLions. With three bones: the femur, fibula, and astragalus.
Attacli/ment of Muscles. To the inner tuberosity, the Semimembranosus: to
the outer tuberosity, the Tiljialis anticusand Extensor longus digitorum : to the
shaft, its internal surface, t])e Sartorius, Gracilis, and Semitendinosus; to its ex-
ternal surface, the Tibialis antions; to its posterior surface, the Popliteus, Soleus
Flexor longus digitorum, and Tibialis posticus ; to the tubercle, the ligamentum
])jilcllfe.
FIBULA.
265
Fig. 204.— Plan of the Development of the
Tibia. By 'J'hree Centres.
iupp^^ ^^^^^/^f^
AppDccys oit birth-
^oirU' Sliaft about
ZSWyS
The Fibula. (Figs. 202, 203.)
The Fibula is situated at the outer side of the leg. It is the smaller of the two
bones, and, in proportion to its length, the most slender of all the long bones ; it
is placed nearly parallel with the tibia. Its upper extremity is small, placed
below the level of the knee-joint, and excluded from its formation ; the lower
extremity inclines a little forwards, so as to be on a plane anterior to that of the
upper end, projects below the tibia, and forms the outer ankle. It presents for
examination a shaft and two extremities.
The Upper Extremity, or Head^ is of an irregular rounded form, presenting
above a flattened articular facet, directed upwards and inwards, for articulation
with a corresponding facet on the ex-
ternal tuberosity of the tibia. On the
cuter side is a thick and rough promi-
nence, continued behind into a pointed
eminence, the styloid process, which
projects upwards from the posterior
part of the head. The prominence gives
attachment to the tendon of the Biceps
muscle, and to the long external lateral
ligament of the knee, the ligament di-
viding the tendon into two parts. The
summit of the styloid process gives at-
tachment to the short external lateral
ligament. The remaining part of the
circumference of the head is rough, for
the attachment of the anterior supe-
rior tibio-fibular ligament, and the up-
per and anterior part of the Pero-
neus longus in front ; and of the pos-
terior superior tibio-fibular ligament
and the upper fibres of the outer head
of the Soleus muscle behind.
^\\Q Lower Extremity, or external mal-
leolus, is of a pyramidal form, some-
what flattened from without inwards,
and is longer, and descends lower, than
the internal malleolus. Its external sur-
face is convex, subcutaneous, and continuous with a triangular (also subcuta-
neous) surface on the outer side of the shaft. The internal surface presents in
front a smooth triangular facet, broader above than below, and convex from
above downwards, which articulates with a corresponding surface on the outer
side of the astragalus. Behind and beneath the articular surface is a rough
depression, which gives attachment to the posterior fasciculus of the external
lateral ligament of the ankle. The anterior horder is thick and rough, and
marked below by a depression for the attachment of the anterior fasciculus of
the external lateral ligament. The posterior horder is broad and marked by a
shallow groove for the passage of the tendons of the Peroneous longus and
brevis muscles. The summit is rounded, and gives attachment to the middle
fasciculus of the external lateral ligament.
The Shaft presents three surfaces and three borders. The anterior horder
commences above in front of the head, runs vertically downwards to a little
below the middle of the bone, and then, curving a little outwards, bifurcates
below. The two lines so formed bound the triangular subcutaneous surface
immediately above the outer side of the external malleolus. This border gives
attachment to an intermuscular septum, which separates the muscles on the
anterior surface from those on the external.
Ajijiears at 2f^y^.
Joins SJi 41 ft a hou*
266 THE SKELETON.
The iiiternal harder^ or interosseous ridge^ is situated close to tlie inner side of
the preceding, and runs nearly parallel with it in the upper third of its extent,
but diverges from it so as to include a broader space in the lower two-thirds.
It commences above just beneath the head of the bone (sometimes it is quite
indistinct for about an inch below the head), and terminates below at the apex
of a rough triangular surface immediately above the articular facet of the ex-
ternal malleolus. It serves for the attachment of the interosseous membrane,
and separates the extensor muscles in front from the flexor muscles behind.
The portion of bone included between the anterior and interosseous lines forms
the anterior surface.
The iMsterior border is sharp and prominent ; it commences above at the base
of the styloid process, and terminates below in the posterior border of the outer
malleolus. It is directed outwards above, backwards in the middle of its course,
backwards and a little inwards below, and gives attachment to an aponeurosis
which separates the muscles on the outer from those on the inner surface of the
shaft. The portion of bone included between this line and the interosseous
ridge, and which includes more than half of the whole circumference of the
fibula, is known as the internal surface. Its upper three-fourths are subdivided
into two parts, an anterior and a posterior, by a very prominent ridge, the ohlique
line of the fibula^ which commences above at the inner side of the head, and
terminates by becoming continuous with the interosseous ridge at the lower
fourth of the bone. The oblique line attaches an aponeurosis which separates
the Tibialis posticus from the Soleus above, and the Flexor longus pollicis below.
This line sometimes ceases just before approaching the interosseous ridge.
The anterior surface is the interval between the anterior and interosseous
borders. It is extremely narrow and flat in the upper third of its extent ;
broader and grooved longitudinally in its lower third; it serves for the attach-
ment of three muscles, tlie Extensor longus cligitorum, Peroneus tertius, and
Extensor proprius pollicis.
The external surface^ much broader than the preceding, and often deeply
grooved, is directed outwards in the upper two-thirds of its course, backwards
in the lower third, where it is continuous with the posterior border of the ex-
ternal malleolus. This surface is completely occupied by the Peroneus longus
and brevis muscles.
The internal surface is the interval between the interosseous ridge and the
posterior border, and occupies nearly two-thirds of the circumference of the bone.
Its upper three-fourths are divided into an anterior and a posterior portion by a
very prominent ridge already mentioned, the oblique line of the fibula. The
anterior portion is directed inwards, and is grooved for the attachment of the
Til)ialis posticus muscle. The posterior portion is continuous below with the
rough triangular surface above the articular facet of the outer malleolus; it is
directed backwards above, backwards and inwards at its middle, directly inwards
below. Its upper third is rough, for the attachment of the Soleus muscle; its
lower part presents a triangular rough surface, connected to the tibia by a strong
interosseous ligament, and between these two points the entire surfiicc is covered
V)y tlie fibres of origin of the Flexor longus pollicis muscle. At about the middle
of this surface is the nutrient foramen, which is directed downwards.
In order to distinguish the side to which the bone belongs, hold it with the
lower extremity downwards, and the broad groove for the Pcronei tendons back-
wards, towards the lioldcr: the triangular subcuUincous surface will then be
directed to tlic side to which the bone belongs.
Articulations. With two bones: the tibia and astragalus.
Development. By three centres (Fig, 205) : one for the shaft, and one for
each extremity. Ossification commences in the shaft about the sixth week of
fojtal life, a little later thiin in 1he tibia, and extends gradually towards the
extremities. At birth both ciid.^ are cartiliiginons. Ossification commences in
ihc lower end in the second yc;ir, ami iu llic ii]>])('r one about the fourth year.
CALCANEUM.
267
Fig. 205. — Plan of the Development
of the Fibula. By 'J'hree Centres.
A^jj-:Pi about lfl';ij.~ri^^VVTnt,tos about 25 i^ if,
The lower epiphysis, tlie first in which ossifi-
cation commences, becomes united to the sliaft
first, contrary to the law which appears to
prevail with regard to the junction of epiphyses
with diaphyses: this takes place about the
twentieth year; the upper epiphysis is joined
about the twenty-fifth year.'
Attachment of Muscles. To the head, the
Biceps, Soleus, and Peroneus longus: to the
shaft, its anterior surface, the Extensor longus
digitorum, Peroneus tertius, and Exteusor pro-
prius pollicis ; to the internal surface, the Soleus,
Tibialis posticus, and Flexor longus pollicis : to
the external surface, the Peroneus longus and
brevis.
THE FOOT. (Figs. 206, 207.)
The skeleton of the Foot consists of three
divisions : the Tarsus, Metatarsus, and Phalanges.
The Taksus.
The bones of the Tarsus are seven in num-
ber: viz., the calcaneum, or os calcis, astragalus. Appears ats.vfy^^^'^^Vnitesaloutzo^Aif-
cuboid, scaphoid, internal, middle, and external '^ \|/ •;5?^
cuneiform iDones. ^^ extt'^
The Calcan'eum.
The Calcaneum, or Os Calcis, is the largest and strongest of the tarsal bones.
It is irregularly cuboidal in form, and situated at the lower and back part of the
foot, serving to transmit the weight of the body to the ground, and forming a
strong lever for the muscles of the calf. It j)resents for examination six surfaces :
superior, inferior, external, anterior, and posterior.
The superior surface is formed behind, of the upper aspect of that part of the
os calcis which projects backwards to form the heel. It varies in length in
different individuals; is convex from side to side, concave from before back-
wards, and corresponds above to a mass of adipose substance placed in front of
the tendo Achillis. In the middle of the superior surface are two (sometimes
three) articular facets, separated by a broad shallow groove, which is directed
obliquely forwards and outwards, and is rough for the attachment of the inter-
osseous ligament connecting the astragalus and os calcis. Of the two articular
surfaces, the external is the larger, and situated on the body of the bone: it is
of an oblong form, wider behind than in front, and convex from before back-
wards. The internal articular surface is supported on a projecting process of
bone, called the lesser process of the calcaneum (sustentaculum tali); it is also
oblong, concave longitudinally, and sometimes subdivided into two parts, which
differ in size and shape. More anteriorly is seen the upper surface of the greaier
process, marked by a rough depression for the attachment of numerous hgaments,
and the origin of the Extensor brevis digitorum muscle.
The inferior surface is narrow, rough, uneven, wider behind than in front,
and convex from side to side ; it is bounded posteriorly by two tubercles, sepa-
rated by a rough depression ; the external, small, prominent, and rounded, gives
attachment to part of the Abductor minimi digiti ; the internal, broader and
' It will be observed that in the fibula, as in other long bones, the epiphysis towards which
the nutrient artery is directed is the one first joined to the shaft.
268
THE SKELETON.
Fig. 206 — Boaes of the Right Foot. Dorsal Surface.
r~„^,^ J- M^«S Astraqajl ubs sf
JKl^^^"^ ''■'■tVy bones ^
Mi"
Go-OOL-e for PEH0NEU3 ESEVIS
C-ivoKe for Tf.n^on. of
rx.'DitlH LCINCUS POLLiCIS
TaTS US
Met a to. rsus
EXT.EREVIS DICITOKUM
TJiMlcunges
tXT. LONCUS PCtLlCIS
CUBOID. 2G9
larger, for tlie support of the heel, gives attachment, by its prominent inner
margin, to the Abductor poUicis, and in front to the Flexor brevis digitorum
muscles; the depression between the tubercles attaches the Abductor minimi
digiti and plantar fascia. The rough surface in front of the tubercles gives
attachment to the long plantar ligament, and to the outer head of the Flexor
accessorius muscle ; and to a prominent tubercle nearer the anterior part of the
bone, as well as to a transverse groove in front of it, is attached the short
plantar ligament.
The external surface is broad, flat, and almost subcutaneous ; it presents near
its centre a tubercle, for the attachment of the middle fasciculus of the external
lateral ligament. Above the tubercle is, a broad smooth surface, giving attach-
ment, at its upper and anterior part, to the external calcaneo-astragaloid liga-
ment ; and in front of the tubercle a narrow surface marked bj two oblique
grooves, separated by an elevated ridge : the superior groove transmits the
tendon of the Peroneus brevis ; the inferior, the tendon of the Peroneus longus ;
the intervening ridge gives attachment to a prolongation from the external annu-
lar ligament.
The internal surface presents a deep concavity, directed obliquely downwards
and forwards, for the transmission of the plantar vessels and nerves and Flexor
tendons into the sole of the foot ; it affords attachment to part of the Flexor
accessorius muscle. This surface presents an eminence of bone, the lesser pro-
cess, which projects horizontally inwards from its upper and fore part-, and to
which a slip of the tendon of the Tibialis posticus is attached. This process is
concave above, and supports the anterior articular surface of the astragalus;
below, it is convex, and grooved for the tendon of the Flexor longus pollicis.
Its free mars:in is rous-h for the attachment of li2:aments.
The anterior surface, of a somewhat triangular form, is smooth, concavo-con-
vex, and articulates with the cuboid. It is surmounted, on its outer side, by a
rough prominence, which forms an important guide to the surgeon in the per-
formance of Ohopart's amputation.
The posterior surface is rough, prominent, convex, and wider below than
above. Its lower part is rough, for the attachment of the tendo Achillis, and
of the Plantaris muscle ; its upper part is smooth, coated with cartilage, and
corresponds to a bursa which separates that tendon from the bone.
Articulations. With two bones : the astraoralus and cuboid.
Attachment of Muscles. Part of the Tibialis posticus, the tendo Achillis, Plan-
taris, Abductor pollicis. Abductor minimi digiti. Flexor brevis digitorum,
Flexor accessorius, and Extensor brevis digitorum.
The Cuboid.
The Cuboid Bone is placed on the outer side of the foot, in front of the os
calcis, and behind the fourth and fifth metatarsal bones. It is of a pyramidal
shape, its base being directed upwards and inwards, its apex downwards and
outwards. It may be distinguished from the other tarsal bones by the existence
of a deep groove on its under surface, for the tendon of the Peroneus longus
muscle. It presents for examination six surfaces: three articular and three
non- articular.
The non-articular surfaces are the superior, inferior, and external. The
superior or dorsal surface, directed upwards and outwards, is rough, for the
attachment of numerous ligaments. The inferior or plantar swr/ace presents in
front a deep groove, which runs obliquely from without, forwards and inwards;
it lodges the tendon of the Peroneus longus, and is bounded behind by a promi-
nent ridge, terminating externally in an eminence, the tuberosity of the cuboid,
the surface of which presents a convex facet, for articulation with the sesamoid
bone of the tendon contained in the groove. The ridge and surface of bone
behind it are rough, for the attachment of the long and short plantar ligaments.
270 THE SKELETON.
A few fibres of tlie Flexor brevis pollicis may be traced to this surface. Tlie
external surface^ the smallest and narrowest of tlie tliree, presents a deep notch
formed bj the commencement of the peroneal groove.
The articular surfaces are the posterior, anterior, and internal. The j^osterior
surface is smooth, triangular and concavo-convex, for articulation with the ante-
rior surface of the os calcis. The anterior, of smaller size, but also irregularly
triangular, is divided by a vertical ridge into two facets : the inner facet, quad-
rilateral in form, articulates with the fourth metatarsal bone : the outer one,
larger and more triangular, articulates with the fifth metatarsal. The internal
surface is broad, rough, irregularly quadrilateral, presenting at its middle and
iij)per part a small oval facet, for articulation with the external cuneiform bone ;
and behind this (occasionally) a smaller facet, for articulation with the scaphoid ;
it is rough in the rest of its extent, for the attachment of strong interosseous
ligaments.
To ascertain to which foot it belongs, hold the bone so that its under surface,
marked by the peroneal groove, looks downwards, and the large concavo-convex
articular surface backwards, towards the holder : the narrow non-articular surface,
marked by the commencement of the peroneal groove, will point to the side to
which the bone belongs.
Articulations. With four bones: the os calcis, external cuneiform, and the
fourth and fifth metatarsal bones, occasionally with the scaphoid.
Attachment of Muscles. Part of the Flexor brevis pollicis.
The Astragalus.
The Astragalus (Fig. 206) is the largest of the tarsal bones, next to the os
calcis. It occupies the middle and upper part of the tarsus, supporting the tibia-
above, articulating with the malleoli on either side, resting below upon the os
calcis, and joined in front to the scaphoid. This bone may easily be recognized
by its large rou.nded head, by the broad articular facet on its upper convex
surface, or by the two articular facets separated by a deep groove on its under
concave surface. It presents six surfaces for examination.
The superior surface presents, behind, a broad smooth trochlear surface, for
articulation with the tibia. The trochlea is broader in front than behind, convex
from before backwards, slightly concave from side to side; in front of it is the
upper surface of the neck of the astragalus ; rough for the attachment of liga-
ments. The inferior surface presents two articular facets separated by a deep
groove. The groove runs obliquely forwards and outwards, becoming gradually
broader and deeper in front: it corresponds with a similar groove upon the
upper surface of the os calcis, and forms, when articulated with that bone, a
canal, filled up in the recent state by the calcaneo-astragaloid interosseous liga-
ment. Of the two articular facets, the posterior is the larger, of an oblong form,
and deeply concave from side to side; the anterior, although nearly of equal
length, is narrower, of an elongated oval form, convex longitudinally, and often
subdivided into two by ?in elevated ridge ; of these the posterior articulates with
the lesser process of the os calcis; the anterior, with the upper surface of the
calcanco-scaphoid ligament. The internal surface presents at its upper part a
pear-shaped articular facet for the inner malleolus, continuous above with the
trochlear surface; below the articular surface is a rough dc])rcssion, for the
attachment of the deep portion of the internal lateral ligament. Tlie external
surface presents a largo Iriangular facet, concave from above downwards, for
articulation willi the external malleolus; it is continuous a])ove with the troch-
lear surfa(;e ; and in front f)P it is a rough depression for the attachment of the
anterior fascicn 1 1 is oC 1 1 k; external lateral ligament. The anterior surface, convex
and rounded, forms the head of the astragalus; it is smooth, of an oval form,
and directed oblif]uely inwards and downwards: it is continuous below with
that part of ihc an1cri<^r facet on the under surface whi(jh rests upon the cal-
ASTRAGALUS.
Fig. 207.— Bonas of the Right Foot. Plantar Surface.
271
ERrlEAttOFACCESSOi.
fLEXOR BRFVIS POtllOIS
Tuhrch of
TIBIAtrs ANTICUSi
FLEXOR LONCUS
DICITORUM
272 THE SKELETON.
caneo-scaplioid ligament. The liead is surrounded by a constricted portion, the
neck of the astragalus. The posterior surface is narrow, and traversed by a
groove, which runs obliquely doAvnwards and inwards, and transmits the tendon
of the Flexor longus pollicis, external to which is a horizontal notch or depres-
sion, in which the posterior fasciculus of the external lateral ligament is lodged.
To ascertain to which foot it belongs, hold the bone with the broad articular
surface upwards, and the rounded head forwards ; the lateral triangular articular
surface for the external malleolus will then point to the side to Avhich the bone
belongs.
Articulations. With four bones : tibia, fibula, os calcis and scaphoid.
The Scaphoid.
The Scaphoid or Navicular Bone, so called from its fancied resemblance to a
boat, is situated at the inner side of the tarsus, between the astragalus behind
and the three cuneiform bones in front. This bone may be distinguished by its
form, being concave behind, convex and subdivided into three facets in front.
The anterior surface^ of an oblong form, is convex from side to side, and sub-
divided by two ridges into three facets, for articulation with the three cuneiform
bones. The posterior surface is oval, concave, broader externally than internally,
and articulates with the rounded head of the astragalus. The superior surface
is convex from side to side, and rough for the attachment of ligaments. The
inferior is somewhat concave, irregular, and also rough for the attachment of
ligaments. The internal surface presents a rounded tubercular eminence, the
tuberosity of the scaphoid, which gives attachment to part of the tendon of the
Tibialis posticus. The external surface is broad, rough, and irregular, for the
attachment of ligamentous fibres, and occasionally presents a small facet for
articulation with the cuboid bone.
To ascertain to which foot it belongs, hold the bone with the concave articular
surface backwards, and the convex dorsal surface upwards ; the broad external
surface will point to the side to which the bone belongs.
Articulations. With four bones : astragalus and three cuneiform ; occasionally
also with the cuboid.
Attachment of Muscles. Part of the Tibialis posticus.
The Cuneiform Bones have received their name from their wedge-like shape.
They form with the cuboid the most anterior row of the tarsus, being placed
between the scaphoid behind, the three innermost metatarsal bones in front, and
the cuboid externally. They are called the firsts second, and third, counting Irom
the inner to the outer side of the foot, and, from their position, internal, middle,
and external.
The Internal Cfneiform.
The Internal Cnnciform is the largest of the three. It is situated at the inner
side of the foot, between tlie scaphoid behind and the base of th(> first meta-
tarsal in front. It may be distinguished from the other two by its large size,
and its more irregular wedge- like form. Without the others, it may be known
by the large kidney-shaped anterior articulating surface, and by the prominence
on the non-articular surface (or base of the wedge), for the attachment of a, large
tendon. It presents for examination six surfaces.
The internal surface is subcutaneous, and forms j^art of the inner border of
the foot; it is broad, f|uadrilateral, and presents at its anterior inferior angle a
smooth oval facet, over wliich tlic tendon of the Tibialis anticus muscle glides:
in the rest of its extent it is rough, for llie attachment of ligaments. The
t'xternal surface is conciive, presenting, along its superior and posterior' borders,
a narrow surface for articulation with the middle cunciibrm behind, and second
CUNEIFORM. 273
metatarsal bone in front : in the rest of its extent, it is rougli for tlie attachment
of ligaments, and prominent below, where it forms part of the tuberosity. The
anterior surface^ kidney-shaped, articulates with the metatarsal bone of the great
toe. The posterior surface is triangular, concave, and articulates with the inner-
most pmd largest of the three facets on the anterior surface of the scaphoid.
The inferior or plantar surface is rough, and presents a prominent tuberosity at
its back part for the attachment of part of the tendon of the Tibialis posticus.
It also gives attachment in front to part of the tendon of the Tibialis anticus.
The superior surface is the narrow pointed end of the wedge, which is directed
upwards and outwards ; it is rough for the attachment of ligaments.
To ascertain to which side it belongs, hold the bone so that its superior
narrow edge looks upwards, and the long, kidney-shaped, articular surface for-
wards ; the external surface, marked by its vertical and horizontal articular
facets, will point to the side to which it belongs.
Articulations. With four bones : scaphoid, middle cuneiform, first and second
metatarsal bones.
Attachment of Muscles. The Tibialis anticus and posticus.
The Middle Cukeifoem.
The Middle Cuneiform, the smallest of the three, is of very regular wedge-
like form, the broad extremity being placed upwards, the narrow end downwards.
It is situated between the other two bones of the same name, and corresponds
to the scaphoid behind, and the second metatarsal in front. It may be distin-
guished from the external cuneiform bone, which it much resembles in general
appearance, by the articular facet, of angular form, which runs round the upper
and back part of its inner surface ; and if the two bones from the same foot are
to2;ether, the middle cuneiform is much the smaller.
The anterior surface^ triangular in form, and narrower than the posterior,
articulates with the base of the second metatarsal bone. The posterior surface^
also triangular, articulates with the scaphoid. The internal surface presents an
articular facet, running along the superior and posterior borders, for articulation
with the internal cuneiform, and is rough below for the attachment of ligaments.
The external surface presents posteriorly a smooth facet for articulation with the
external cuneiform bone. The superior surface forms the base of the wedge ; it
is quadrilateral, broader behind than in front, and rough for the attachment of
ligaments. The inferior surface^ pointed and tubercular, is also rough for liga-
mentous attachment.
To ascertain to which foot the bone belongs, hold its superior or dorsal surface
upwards, the broadest edge being towards the holder : the smooth facet (limited
to the posterior border) will then point to the side to which it belongs.
Articulations. With four bones : scaphoid, internal and external cuneiform,
and second metatarsal bone.
Attachment of Muscle. A slip from the tendon of the Tibialis posticus is
attached this bone.
The External Cuneiform.
The External Cuneiform, intermediate in size between the two preceding, is
of a very regular wedge-like form, the broad extremity being placed upwards,
the narrow end downwards. It occupies the centre of the front row of the
tarsus between the middle cuneiform internally, the cuboid externally, the sca-
phoid behind, and the third metatarsal in front. It is distinguished from the
internal cuneiform bone b}^ its more regular Avedge-like shape, and by the
absence of the kidney-shaped articular surface : from the middle cuneiform, by
the absence of the bent, or angular, facet, and by the two articular facets which
mark both its inner and outer surfaces. It has six surfaces for examination.
18
274 THE SKELETON.
The anterior surface^ triangular in form, articulates witli the third metatarsal
bone. The -posterior surface articulates with the most external facet of the sca-
phoid, and is rough below for the attachment of ligamentous fibres. The internal
surface presents two articular facets separated by a rough depression ; the anterior
one, situated at the superior angle of the bone, articulates with the outer side of
the base of the second metatarsal bone; the posterior one skirts the posterior
border, and articulates with the middle cuneiform ; the rough depression between
the two gives attachment to an interosseous ligament. The external surface also
presents two articular facets, separated by a rough non-articular surface; the
anterior facet, situated at the superior angle of the bone, is small, and articulates
with the inner side of the base ofthe fourth metatarsal; the posterior, and larger
one articulates with the cuboid; the rough non-articular surface serves for the
attachment of an interosseous ligament. The three facets for articulation with
the three metatarsal bones are continuous with one another, and covered by a
prolongation of the same cartilage ; the facets for articulation with the middle
cuneiform and scaphoid are also continuous, but that for articulation with the
cuboid is usually separate. The superior or dorsal surface^ of an oblong form,
is rough for the attachment of ligaments. The inferior or plantar surface is an.
obtuse rounded margin, and serves for the attachment of part of the tendon of
the Tibialis posticus, part of the Flexor brevis pollicis, and ligaments.
To ascertain to which side it belongs, hold the bone with the broad dorsal
surface upwards, the prolonged edge backwards ; the separate articular facet for
the cuboid will point to the proper side.
Articulations. With six bones : the scaphoid, middle cuneiform, cuboid, and
second, third, and fourth metatarsal bones.
Attachment of Muscles. Part of Tibialis posticus, and Flexor brevis pollicis.
The Metatarsal Bones,
The Metatarsal Bones are five in number ; they are long bones, and subdivided
into a shaft and two extremities.
Common characters. The Shaft is prismoid in form, tapers gradually from the
tarsal to the phalangeal extremity, and is slightly curved longitudinally, so as to
be concave below, slightly convex above. The Posterior Extremity^ or Base^ is
wedge-shaped, articulating by its terminal surface with the tarsal bones, and by
its lateral surfaces with the contiguous metatarsal bones ; its dorsal and plantar
surfaces being rough for the attachment of ligaments. The Anterior Extremity^
or Head.^ presents a terminal rounded articular surface, oblong from above down-
wards, and extending further backwards below than above. Its sides are flat-
tened, and present a depression, surmounted by a tubercle, for ligamentous
attachment. Its under surface is grooved in the middle line for the passage of
the Flexor tendon, and marked on each side by an articular eminence continuous
with the terminal articular surface.
Peculiar characters. The First is remarkable for its great size, but is the shortest
of all the metatarsal bones. The sliaft is strong, and of well-marked prismoid
form. The posterior extremity presents no lateral articular facets ; its terminal
articular surface is of large size, of semilunar form, and its circumference grooved
for the tarso-mctatarsal ligaments ; its inferior nngle presents a rimgh oval pro-
minence for the insertion of tlic tendon of the Pcroncus longus. The head is of
large size; on its plantar surface arc two grooved facets, over which glide sesa-
moid bones; the facets are separated by a smooth elevated ridge.
This bone is known by the single kidney-shaped articular surface on its base;
the deeply grooved appearance of the ])lantar surface of its head ; and its great
thickness, relatively to its length. Wlien it is ]iliiced in its natural ])osition, the
concave border of the kidncy-sliaped articular surface on its base points to the
side to which lhc bone belongs.
PHALANGES. 275
Tile Second is tlae longest and largest of tlie remaining metatarsal bones, being
prolonged backwards into the recess formed between tke three cnneiform bones.
Its tarsal extremity is broad above, narrow and rough below. It presents four
articular surfaces : one behind, of a triangular form, for articulation with the
middle cuneiform ; one at the upper part of its internal lateral surface, for articu-
lation with the internal cuneiform ; and two on its external lateral surface, a supe-
rior and an inferior, separated by a rough depression. Each of the latter
articular surfaces is divided by a vertical ridge into two parts ; the anterior seg-
ment of each facet articulates with the third metatarsal ; the two posterior (some^
times continuous) with the external cuneiform.
The facets on the tarsal extremity of the second metatarsal bone serve at once
to distinguish it from the rest and to indicate the foot to which it belongs ; there
being one facet at the upper angle of the internal surface, and two facets, each
subdivided into two parts, on the external surface, pointing to the side to which
the bone belongs. The fact that the two posterior subdivisions of these external
facets sometimes run into one should not be forgotten.
The Third articulates behind, by means of a triangular smooth surface, with
the external cuneiform ; on its inner side, by two facets, with the second meta-
tarsal ; and on its outer side, by a single facet, with the fourth metatarsal. The
latter facet is of circular form, and situated at the upper angle of the base.
The third metatarsal is known by its having at its tarsal end two undivided
facets on the inner side, and a single facet on the outer. This distinguishes it
from the second metatarsal, in which the two facets, found on one side of its tarsal
end, are each subdivided into two. The single facet (when the bone is put in its
natural position) is on the side to which the bone belongs.
The Fourth is smaller in size than the preceding ; its tarsal extremity pre-
sents a terminal quadrilateral surface, for articulation with the cuboid ; a smooth
facet on the inner side, divided by a ridge into an anterior portion for articulation
with the third metatarsal, and a posterior portion for articulation with the ex-
ternal cuneiform; on the outer side a single facet, for articulation with the fifth
metatarsal.
The fourth metatarsal is known by its having a single facet, on either side of
the tarsal extremity, that on the inner side being divided into two parts. If this
subdivision be not recognizable, the fact that its tarsal end is bent somewhat out-
wards will indicate the side to which it belongs, as Mr. Holden points out.
The Fifth is recognized by the tubercular eminence on the outer side of its
base. It articulates behind, by a triangular surface cut obliquely from without
inwards, with the cuboid : and internally, with the fourth metatarsal.
The projection on the outer side of this bone at its tarsal end at once distin-
guishes it from the others, and points to the side to which it belongs.
Articulations. Each bone articulates with the tarsal bones by one extremity,
and by the other with the first row of phalanges. The number of tarsal bones
with which each metatarsal articulates, is one for the first, three for the second,
one for the third, two for the fourth, and one for the fifth.
Attachment of Muscles. To the first metatarsal bone, three : part of the Tibialis
anticus, the Peroneus longus, and First dorsal interosseous. To the second, three :
the Adductor pollicis, and First and Second dorsal interosseous. To the third,
four : the Adductor pollicis. Second and Third dorsal, and first plantar interos-
seous. To the fourth, four : the Adductor pollicis. Third and Fourth dorsal, and
Second plantar interosseous. To the fifth, five : the Peroneus brevis, Peroneus
tertius, Flexor brevis minimi digiti. Fourth dorsal, and Third plantar interosseous.
Phalanges.
The Phalanges of the foot, both in number and general arrangement, resemble
those in the hand ; there being two in the great toe, and three in each of the
other toes.
276 THE SKELETON.
The plialanges of tlie first row resemble closely those of the nand. The shaft
is compressed from side to side, convex above, concave below. The posterior
extrer)%ity is concave ; and the anterior extremity presents a trochlear surface, for
articulation with the second phalanges.
The phalanges of the second roiu are remarkably small and short, but rather
broader than those of the first row.
The wn,(/2<aZ phalanges, in form, resemble those of the fingers; but they are
smaller, flattened from above downwards, presenting a broad base for articula-
tion with the second row, and an expanded extremity for the support of the
nail and end of the toe.
Articulatio7i. The first row, with the metatarsal bones, and second phalanges ;
the second of the great toe, with the first phalanx, and of the other toes, with
the first and third phalanges ; the third with the second row.
Attachment of Muscles. To the first phalanges, great toe : innermost tendon
of Extensor brevis digitorum, Abductor poUicis, Adductor pollicis. Flexor brevis
pollicis, Transversus pedis. Second toe : First and Second dorsal interosseous.
Third toe : Third dorsal and First plantar interosseous. Fourth toe : Fourth
dorsal and Second plantar interosseous. Fifth toe : Flexor brevis minimi digiti.
Abductor minimi digiti, and Third plantar interosseous. Second phalanges,
great toe : Extensor longus pollicis, Flexor longus pollicis. Other toes : Flexor
brevis digitorum, one slip from the Extensor brevis digitorum (except in the
little toe), and Extensor longus digitorum. Third phalanges : two slips from
the common tendon of the Extensor longus and Extensor brevis digitorum, and
the Flexor longus digitorum.
Development of the Foot. (Fig. 208.)
The Tarsal bones are each developed by a single centre, excepting the os
calcis, which has an epiphysis for its posterior extremity. The centres make
their appearance in the following order : os calcis, at the sixth month of foetal
life ; astragalus, about the seventh month ; cuboid, at the ninth month ; external
cuneiform, during the first year ; internal cuneiform in the third year ; middle
cuneiform and scaphoid in the fourth year. The epiphysis for the posterior
tuberosity of the os calcis appears at the tenth year, and unites with the rest of
the bone soon after puberty.
The Metatarsal bones are each developed by two centres; one for the shaft,
and one for the digital extremity, in the four outer metatarsal; one for the
shaft, and one for the base, in the metatarsal bone of the great toe. Ossification
commences in the centre of the shaft about the seventh week, and extends to-
wards either extremity, and in the digital epiphyses about the third year ; they
become joined between the eighteenth and twentieth years.
Tlie Phalanges are developed by tvjo centres for each bone : one for the shaft,
and one for the metatarsal extremity.
Sesamoid Bones.
These are small I'Duiulcd masses, cartilaginous in early life, osseous in the
jiflult, wliicli are developed in those tendons which exert a great amount of pres-
sure upon the |)arts over which they glide. It is said that they are more com-
monly foiiinl ill the male than in the female, and in persons of an active
muscular habit than in those who are weak and debilitated. They are invested
throughout their whole surface by the fibrous tissue of the tendon in which they
are found, excepting u])on that side which, lies in contact witli the part over
which they play, where they present a free articular facet. They may be divi-
<led into 1 wo kinds: those which glide over the articular surfaces of joints, and
those which jjlay over the cartilaginous facets found on the surfaces of certain
bones.
The sesamoid bones of Ihc joints are, in the lower cxtromily, the patella, which
SESAMOID BONES,
277
is developed in the tendon of the Quadriceps extensor; two small sesamoid
bones, found in the tendons of the Flexor brevis pollicis opposite the metatarso-
phalangeal joint of the great toe, and occasionally one in the metatarso-phalan-
geal joint of the second toe, the little toe, and, still more rarely, the third and
fourth toes.
Fig. 208.— Plan of the Development of the Foot.
unites after ^ulert'j
Tarsus ^
/ Centre for caeJi io7io
excx'pt Ox Calcic
Metatarsus
it Centres for each bone
1 for Shaft
1 for Diqital Extremity
ea:ccvt i.f?
.3_3^ Apjxyars S^'' t/''
Unite 18-2VyA
App?- 3^'^ '/■'''— &ad
m:^j3
FAalanges
2Centresfcrr eacJi, I/one
fforSliafl
t forMetntarsalJExt.V
App-ZrUirw: — \
In the upper extremity, there are two on the palmar surface of the metacarpo-
phalangeal joint in the thumb, developed in the tendons of the Flexor brevis
pollicis, occasionally one or two opposite the metacarpo-phalangeal articula-
tions of the fore and little fingers, and, still more rarely, one opposite the same
joints of the third and fourth fingers.
Those found in the tendons which glide over certain bones, occupy the follow-
ing situations : one in the tendon of the Peroneus longus, where it glides through
the groove in the cuboid bone : one appears late in life in the tendon of the
Tibialis anticus, .opposite the smooth facet on the internal cuneiform bone: one
is found in the tendon of the Tibialis posticus, opposite the inner side of the
astragalus ; one in the outer head of the Gastrocnemius, behind the outer con-
dyle of the femur ; and one in the Psoas and Iliacus, where they glide over the
body of the pubes. Sesamoid bones are found occasionally in the tendon of the
Biceps, opposite the tuberosity of the radius ; in the tendon of the Gluteus
maximus, as it passes over the great trochanter ; and in the tendons which wind
round the inner and outer malleoli.
278 THE SKELETON.
The author has to acknowledge valuable aid derived from the perusal of the works of Cloquet,
Cruveilhier, Bourgery, and Boyei\ especially of the latter. Reference has also been made to the
following : " Outlines of Human Osteology," by F. 0. Ward. " A Treatise on the Human
Skeleton, and Observations on the Limbs of Vertebrate Animals," by G. M. Humphry.
Holden's " Human Osteology." Henle's " Handbuch der systematischen Anatomie des Men-
schen. Erster Band. Erste Abtheilung. Knochenlehre." " Osteological Memoirs (The Clavi-
cle)," by Struthers. " On the Archetype and Homologies of the Vertebrate Skeleton," and " On
the Nature of Limbs," by Owen.- — Todd and Bowman's " Physiological Anatomy," and Kblliker's
" Manual of Human Microscopic Anatomy," contain the most complete account of the structure
and development of bone. — The development of the bones is minutely described in Quain's
" Anatomy." edited by Sharpey and Ellis. — On the chemical analysis of bone, refer to Lehmann's
" Physiological Chemistry," translated by Day ; vol. iii. p. 12. Simon's " Chemistry," translated
by Day ; vol. ii. p. 396. A paper by Dr. Stark, " On the Chemical Constitution of the Bones of
the Vertebrated Animals" (Edinburgh Medical and Surgical Journal ; vol. liii. p. 308) ; and
Dr. Owen Rees' paper in the 21st vol. of the Medico-Chirurgical Transactions.
The Articulations.
The various bones of wliich the skeleton consists are connected together at
different parts of their surfaces, and such a connection is designated by the name
of Joint or Articulation. If the joint is immovable^ as between the cranial and
most of the facial bones, their adjacent margins are applied in almost close con-
tact, a thin layer of fibrous membrane, the sutural ligament^ and, at the base
of the skull, in certain situations, a thin layer of cartilage being interposed.
Where slight movement is required, combined with great strength, the osseous
surfaces are united by tough and elastic fibro-cartilages, as in the joints of the
spine, the sacro-iliao, and interpubic articulations ; but in the movable joints,
the bones forming the articulation are generally expanded for greater con-
venience of mutual connection, covered by cartilage, held together by strong
bands or capsules of fibrous tissue, called ligaments, and lined by a membrane,
the synovial membrane, which secretes a fluid to lubricate the various parts of
which the joint is formed ; so that the structures which enter into the formation
of a joint are bone, cartilage, fibro- cartilage, ligament, and synovial membrane.
Bone constitutes the fundamental element of all the joints. In the long
bones, the extremities are the parts which form the articulations ; they are
generally somewhat enlarged, consisting of spongy cancellous tissue, with a thin
coating of compact substance. In the flat bones, the articulations usually take
place at the edges ; and, in the short bones, at various parts of their surface.
The layer of compact bone which forms the articular surface, and to which the
cartilage is attached, is called the articular lamella. It is of a white color, ex-
tremely dense, and varies in thickness. Its structure differs from ordinary bone
tissue in this respect, that it contains no Haversian canals, and its lacuna are
much larger than in ordinary bone, and have no canaliculi. The vessels of the
cancellous tissue, as they approach the articular lamella, turn back in loops,
and do not perforate it ; this layer is consequently more dense and firmer than
ordinary bone, and is evidently designed to form a firm and unyielding support
for the articular cartilasre.
O
The articular will be found described along with the other kinds of cartilage
in the Introduction.
Ligaments are found in nearly all the movable articulations ; they consist of
bands of various forms, serving to connect together the articular extremities
of bones, and composed mainly of bundles of white fibrous tissue placed parallel
with, or closely interlaced with, one another, and presenting a white, shining
silvery aspect. Ligament is pliant and flexible, so as to allow of the most
perfect freedom of movement, but strong, tough, and inextensile, so as not
readily to yield under the most severely applied force ; it is consequently well
adapted to serve as the connecting medium between the bones. Some ligaments
consist entirely of yelloiu elastic tissue, as the liagmenta subflava, which connect
together the adjacent arches of the vertebrae, and the ligamentum nuchas in the
lower animals. In these cases, it will be observed that the elasticity of the
ligament is intended to act as a substitute for muscular power.
Synovial Membrane is a thin, delicate membrane, arranged in the form of a
short wide tube, attached by its open ends to the margins of the articular ex-
tremities of the bones, and covering the inner surface of the various ligaments
which connect the articulating surfaces. It resembles the serous membranes in
structure, but differs in the nature of its secretion, which is thick, viscid, and
glairy, like the white of egg ; and hence termed synovia. The synovial mem-
(279)
280 AETICULATIONS.
branes found in tlie body admit of subdivision into tliree kinds, articular,
bursal, and vaginal.
The articular synovial memhranes are found in all tlie freely movable joints.
In the foetus, this membrane is said, by Toynbee, to be continued over the sur-
face of the cartilages ; but in the adult it is wanting, excepting at their cir-
cumference, upon which it encroaches for a short distance ; it then invests the
inner surface of the capsular or other ligaments enclosing the joint, and is
reflected over the surface of any tendons passing through its cavity, as the ten-
don of the Popliteus in the knee, and the tendon of the Biceps in the shoulder.
In most of the joints, the synovial membrane is thrown into folds, which pro-
ject into the cavity. Some of these folds contain large masses of fat. These
are especially distinct in the hip and the knee. Others are flattened folds,
subdivided at their margins into fringe-like processes, the vessels of which have
a convoluted arrangement. The latter generally project from the synovial
membrane near the margin of the cartilage, and lie flat upon its surface. They
consist of connective tissue, covered with epithelium, and contain fat cells in
variable quantity, and, more rarely, isolated cartilage cells. They are found in
most of the bursal and vaginal, as well as in the articular synovial membranes,
and were described, by Clopton Havers, as mucilaginous glands, and as the
source of the synovial secretion. Under certain diseased conditions, similar
processes are found covering the entire surface of the synovial membrane, form-
ing a mass of pedunculated fibro-fatty growths, which project into the joint.
The h.ursse are found interposed between surfaces which move upon each other,
producing friction, as in the gliding of a tendon, or of the integument over pro-
jecting bony surfaces. They admit of subdivision into two kinds^ the hursse
rnucosse^ and the synovial hursse. The former are large, simple, or irregular
cavities in the subcutaneous areolar tissue, enclosing a clear viscid fluid. They
are found in various situations, as between the integument and front of the
patella, over the olecranon, the malleoli, and other prominent parts. The syno-
vial hursse are found interposed between muscles or tendons as they play over
projecting bony surfaces, as between the Glutei muscles and the surface of the
great trochanter. They consist of a thin wall of connective tissue, partially
covered by epithelium, and contain a viscid fluid. Where one of these exists in
the neighborhood of a joint, it usually communicates with its cavity, as is gene-
rally the case with the bursa between the tendon of the Psoas and Iliacus and the
capsular ligament of the hip, or the one interposed between the under surface
of the Subscapularis and the neck of the scapula.
The vaginal synovial memhranes (synovial sheaths) serve to facilitate the
gliding of tendons in the osseo-fibrous canals through which they pass. The
membrane is here arranged in the form of a sheath, one layer of which adheres
to the wall of the canal, and the other is reflected upon the outer surface of the
contained tendon ; the space between the two free surfaces of the membrane
being partially filled with synovia. These sheaths are chiefly found surrounding
the tendons of the flexor and extensor muscles of the fingers and toes, as they
pass through the osseo-fibrous canals in the hand or foot.
Synovial a transparent, yellowish-white, or slightly reddish fluid, viscid like
^the white of egg, having an alkaline reaction, and slightly saline taste. It
V^onsists, according to Frcrichs, in the ox, of 94.85 water, OX)G mucus and epithe-
lium, 0.08 fat, B.51 albumen and extractive matter, and 1.0 salts.
The Articulations are divided into three classes : Synarthrosis, or immovable ;
AmpJdarthrosis. or mixed; and Dia,rthrosis, or movable joints.
1. Synaktiirosls. Immovable Articulations.
>S//r<ar///ro.s/.y includes all those articulations in wliich the surfaces of the bones
are in almost direct contact, not separated by nn intervening synovial cavity,
and immovablv connected with each other, as the joints between the bones of
STRUCTURE OF JOINTS. 281
the cranium and face, excepting those of the lower jaw. The varieties of synar-
throsis are three m number: Sutura, Schindylesis, and Gomphosis.
Sutura (a seam). Where the articulating surfaces are connected by a series
of processes and indentations interlocked together, it is termed sutura vera ; of
which there are three varieties : sutura dentata, serrata, and limbosa. The sur-
faces of the bones are not in direct contact, being separated by a layer of mem-
brane, continuous externally with the pericranium, internally with the dura
mater. The sutura dentata (dens, a tooth) is so called from the tooth-like form
of the projecting articular processes, as in the suture between the parietal bones.
In the sutura serrata [serra, a saw), the edges of the two bones forming the articu-
lation are serrated like the teeth of a fine saw, as between the two portions of
the frontal bone. In the sutura limhosa (lunhits, a selvage), besides the dentated
processes, there is a certain degree of bevelling of the articular surfaces, so that
the bones overlap one another, as in the suture between the parietal and frontal
bones. When the articulation is formed by roughened surfaces placed in appo-
sition with one another, it is termed ike false suture, sutura notha, of which there
are two kinds : the sutura squamosa {squama, a scale), formed by the overlap-
ping of two contiguous bones by broad bevelled margins, as in the temporo-
parietal (squamous) suture ; and the sutura harmonia (dp^oj/ta, a joining together),
where there is simple apposition of two contiguous rough bony surfaces as in the
articulation between the two superior maxillary bones, or of the horizontal plates
of the palate bones.
Schindylesis (ff;i;n'6i;x52Ttj, a fissure) \& that form of articulation in which a thin
plate of bone is received into a cleft or fissure formed by the separation of two
laminae of another, as in the articulation of the rostrum of the sphenoid, and per-
pendicular plate of the ethmoid with the vomer, or in the reception of the latter
in the fissure between the superior maxillary and palate bones.
Oomphosis (yo^^oj, a nail) is an articulation formed by the insertion of a coni-
cal process into a socket, as a nail is driven into a board ; this is not illustrated
by any articulations between bones, properly so called, but is seen in the articu-
lation of the teeth with the alveoli of the maxillary bones.
2. Amphiarthkosis. Mixed Articulations.
In this form of articulation, the contiguous osseous surfaces are either con-
nected together by broad flattened disks of fibro-cartilage, which adhere to the
end of both bones, as in the articulation between the bodies of the vertebrte, or
that between the first two pieces of the sternum; or else the articulating surfaces
are covered with fibro-cartilage, partially lined by synovial membrane, and con-
nected together by external ligaments, as in the sacro-iliac and pubic symphyses ;
both these forms being capable of limited motion in every direction. The former
resemble the synarthrodial joints in the continuity of their surfaces, and absence
of synovial sac ; the latter, the diarthrodial. These joints occasionally become
obliterated in old age ; as is frequently the case in the pubic articulation, and
occasionally in the intervertebral and sacro-iliac.
3. DiARTHROsis. Movable Articulations.
This form of articulation includes the greater number of the joints in the body,
mobility being their distingiiishing character. They are formed by the approxi-
mation of two contiguous bony surfaces, covered with cartilage, connected by
ligaments, and lined by synovial membrane. The varieties of joints in this class
have been determined by the kind of motion permitted in each ; they are four in
number: Arthrodia, Enarthrosis, Ginglymus, Diarthrosis rotatoria.
Arthrodia is that form of joint which admits of a gliding movement ; it is
formed by the approximation of plane surfaces, or one slightly concave, the other
slightly convex ; the amount of motion between them being limited by the liga-
282 ARTICULATIONS.
ments, or osseous processes, surrounding the articulation; as in the articular pro-
cesses of the vertebras, temporo-maxillary, sterno- and acromio-clavicular, inferior
radio-ulnar, carpal, carpo-metacarpal, superior tibio-libular, tarsal, and tarso-
metatarsal articulations.
Enarthrosis is that form of joint which is capable of motion in all directions.
It is formed by the reception of a globular head into a deep cup-like cavity (hence
the name " ball and socket"), the parts being kept in apposition by a capsular
ligament strengthened by accessory ligamentous bands. Examples of this form
of articulation are found in the hip and shoulder.
Oinglymus^ Hinge-joint (ytyy^D^oj, a hinge). In this form of joint, the articular
surfaces are moulded to each other in such a manner as to permit motion only
in t^yo directions, forwards and backwards, the extent of motion at the same
time being considerable. The articular surfaces are connected together by strong
lateral ligaments, which form their chief bond of union. The most perfect
forms of ginglymus are the elbow and ankle ; the knee is less perfect, as it allows
a slight degree of rotation in certain positions of the limb : there are also the
metatarso-phalangeal and phalangeal joints in the lower extremity, and the meta-
carpo-phalangeal and phalangeal joints in the upper extremity.
Diarthrosis rotatoria (Lateral Ginglymus). Where the movement is limited
to rotation, the joint is formed by a pivot-like process turning within a ring, or
the ring on the pivot, the ring being formed partly of bone, partly of ligament.
In the articulation of the odontoid process of the axis with the atlas, the ring
is formed in front by the anterior arch of the atlas ; behind, by the transverse
ligament ; here the ring rotates round the odontoid process. In the superior
radio-ulnar articulation, the ring is formed partly by the lesser sigmoid cavity
of the ulna ; in the rest of its extent, by the orbicular ligament ; here, the head
of the radius rotates within the ring.
Subjoined, in a tabular form, are the names, distinctive characters, and
examples of the different kinds of articulations.
STRUCTURE OF JOINTS.
283
Synarthrosis, or
immovable joint.
Surfaces separated
by fibrous mem-
brane, witliont any
intervening syno-
vial cavity, and im-
movably connected
with each other.
As in joints of
cranium and face
(except lower jaw).
Amphiarthrosis^
Mixed Articulation.
Diarthrosis^
Movable joint.
Sutura. Arti-
culation by pro-
cesses and inden-
tations interlock-
ed together.
Dentata^ having
' tooth-like processes.
As in interparie-
tal suture.
Serrata, having
Iserrated edges, like
Sutura vera (true) jthe teeth of a saw.
'articulate by in-/ As in interfrontal
dented borders. \suture.
Limhosa, having
[bevelled margins,
and dentated pro-
cesses.
As in fronto-pa-
^rietal suture.
Squamosa^ formed
^by thin bevelled
margins, overlap-
ping each other.
Sutura notha ^^ /^ squamo-
(false) articulate by /P'^J^etal suture,
trough surfaces. V HcmnomaMmed^
° / by the opposition oi
contiguous rough
surfaces.
As in intermaxil-
lary suture.
Schindylesis. Articulation formed by the reception of a
thin plate of one bone into a fissure of another.
As in articulation of rostrum of sphenoid with vomer.
Gomphosis. Articulation formed by the insertion of a
conical process into a socket.
The teeth.
1. Surfaces connected by fibro-cartilage, not separated
by synovial membrane, and having limited motion. As in
joints between bodies of vertebra.
2. Surfaces covered by fibro-cartilage ; lined by a partial
synovial membrane. As in sacro-iliac and pubic symphyses.
Arthrodia. Gliding joint ; articulations by plane surfaces,
which glide upon each other. As in sterno- and acromio-
clavicular articulations.
Enarthrosis. Ball-and-socket joint ; capable of motion in
all directions. Articulations by a globular head received
into a cup-like cavity. As in hip and shoulder joints.
Ginglymus. Hinge joint ; motion limited to two direc-
tions, forwards and backwards. Articular surfaces fitted
together so as to permit of movement in one plane. As in
the elbow, ankle, and knee.
Diarthrosis rotatoria or Lateral Ginglymus. Articulation
by a pivot process turning within a ring, or ring around a
pivot. As in superior radio-ulnar articulation, and atlo-
axoid joint.
284 ARTICULATIONS.
The Kinds of Movement admitted in Joints.
The movements admissible in joints may be divided into four kinds : gliding,
angular movement, circumduction, and rotation.
Gliding movement is the most simple kind of motion that can take place in a
joint, one surface gliding over another. It is common to all movable joints,
but in some, as in the articulations of the carpus and tarsus, it is the only motion
permitted. This movement is not confined to plane surfaces, but may exist
between any two contiguous surfaces, of whatever form, limited by the ligaments
which inclose the articulation.
Angular movement occurs only between the long bones, and may take place
in four directions, forwards and backwards, constituting flexion and extension,
or inwards and outwards, constituting adduction and abduction. The strictly
ginglymoid or hinge joints admit of flexion and extension only. Abduction
and adduction, combined with flexion and extension, are met with in the more
movable joints; as in the hip, shoulder, and metacarpal joint of the thumb,
and partially in the wrist and ankle.
Circumduction is that limited degree of motion which takes place between
the head of a bone and its articular cavity, whilst the extremity and sides of the
limb are made to circumscribe a conical space, the base of which corresponds
with the inferior extremity of the limb, the apex with the articular cavity ; this
kind of motion is best seen in the shoulder and hip joints.
Eotation is the movement of a bone upon its own axis, the bone retaining the
same relative situation with respect to the adjacent parts ; as in the articulation
between the atlas and axis, where the odontoid process serves as a pivot around
which the atlas turns ; or iu the rotation of the radius upon the humerus, and ,
also in the hip and shoulder.
The actions of the different joints of a limb are combined by means of the
long muscles which pass over more than one joint, and which act to a certain
extent as elastic ligaments in restraining certain actions of one joint, except
when combined with corresponding movements of the other — these latter move-
ments being usually in the opposite direction. Thus the shortness of the ham-
string-muscles prevents complete flexion of the hip, unless the knee-joint be
also flexed so as to bring their attachments nearer together. The uses of this
arrangement are threefold. 1. It co-ordinates the kinds of movement which
are the most habitual and necessary, and enables them to be performed with the
least expenditure of power. " Thus in the usual gesture of the arms, whether
in grasping or rejecting, the shoulder and the elbow are flexed simultaneously,
and simultaneously extended," in consequence of the passage of the Biceps and
Triceps cubiti over both joints. 2. It enables the short muscles which pass
over only one joint to act upon more than one. " Thus if the Eectus fcmoris
remain tonically of such length that when stretched over the extended hip, it
compels extension of the knee, then the Gluteus maximus becomes not only an
extensor of the hip, but an extensor of the knee as well." 3. It provides the
joints with ligaments which, while they are of very great power in resisting
movements to an extent incompatible with the mechanism of the joint, at the
same time spontaneously yield when necessary. " Taxed beyond its strength
a ligament will be ruptured, whereas a contracted muscle is easily relaxed ; also,
if neighboring joints be united by ligaments, the amount of flexion or exten-
sion of each must remain in constant pro])ortion to that of the other; while,
if the unif)n be by muscles, the separation of tlic points of attachment of those
muscles may vary consid('ral)ly in (lirCcrcnt varieties of movement, the muscles
adapting themselves tonically io the length required." The quotations are from
a very interesting paper, by Dr. Cleland, in the "Journal of Anatomy and
Physiology," No. 1, IMOC), p. 85; by whom T believe this important fact in the
mechanism of joinls was first clearly ])oiiilcd out, though it has been indepen-
dently observed afterwards by other aiiatomiHts.
OF THE SPINE. 285
Tlie articulations ma^^ be arranged into those of the trunk, those of the upper
extremity, and those of the lower extremity.
ARTICULATIONS OF THE TEUNK.
These may be divided into the following groups, viz:- — ■
I. Of the vertebral column. YII. Of the cartilages of the ribs with
II. Of the atlas with the axis. the sternum, and with each
III. Of the atlas with the occipital other.
bone. VIII. Of the sternum.
IV. Of the axis with the occipital bone. IX. Of the vertebral column with
V. Of the low^er jaw. the pelvis.
VI. Of the ribs with the vertebrae. X. Of the pelvis.
I. Articulations of the Vertebral Column.
The different segments of the spine are connected together by ligaments, which
admit of the same arrangement as the vertebrae. They may be divided into five
sets. 1. Those connecting the bodies of the vertebrge. 2. Those connecting the
Jaminee. 3. Those connecting the articular processes. 4. Those connecting the
spinous processes. 5. ^\io&q oi i\iQ transverse processes.
The articulations of the bodies of the vertebra with each other form a series
of amphiarthrodial joints: those between the articular processes form a series of
arthrodial joints.
1. The Ligaments of the Bodies.
Anterior Common Lio'ament. Posterior Common Ligament.
Intervertebral Substance.
The Anterior Common Ligament (Figs. 209, 210, 217, 220) is a broad and strong
band of ligamentous fibres, which extends along the front surface of tlie bodies
of the vertebras, from the axis to the sacrum. It is broader below than above,
thicker in the dorsal than in the cervical or lumbar regions, and somewhat thicker
opposite the front of the body of each vertebra, than opposite the intervertebral
substance. It is attached, above, to the body of the axis by a pointed process,
which is connected with the tendon of insertion of the Longus colli muscle ; and
extends down as far as the upper bone of the sacrum. It consists of dense
longitudinal fibres, which are intimately adherent to the intervertebral sub-
stance, and the prominent margins of the vertebrae; but less closely to the
middle of the bodies. In the latter situation the fibres are exceedingly thick,
and serve to fill up the concavities on their front surface, and to make the
anterior surface of the spine more even. This ligament is composed of several
layers of fibres, which vary in length, but are closely interlaced with each
other. The most superficial or longest fibres extend between four or five ver-
tebras. A second subjacent set extend between two or three vertebra?; whilst
a third set, the shortest and deepest, extend from one vertebra to the next. At
the side of the bodies, the ligament consists of a few short fibres, which pass
from one vertebra to the next, separated from the median portion hj large oval
apertures, for the passage of vessels.
The Posterior Comm.on Ligament (Figs. 209, 213) is situated within the spinal
canal, and extends along the posterior surface of the bodies of the vertebra?,
from the body of the axis above, where it is continuous with the occipito-axoid
ligament, to the sacrum below. It is broader at the upper than at tlie lower
part of the spine, and thicker in the dorsal than in the cervical or lumbar
regions. In the situation of the intervertebral substance and contiguous margins
of the vertebrae, where the ligament is more intimately adherent, it is broad,
286
ARTICULATIONS.
and presents a series of dentations with intervening concave margins ; bnt it is
narrow and tliick over tlie centre of tlie bodies, from wliich it is separated by
tlie vends basis vertehrse. Tliis ligament is composed of smooth., shining, longi-
tudinal fibres, denser and more compact than those of the anterior ligament, and
composed of a superficial layer occupying the interval between three or four
vertebra?, and of a deeper layer which extends between one vertebra and the
next adjacent to it. It is separated from the dura mater of the spinal cord by
some loose filamentous tissue, very liable to serous infiltration.
The loitervertehral Suhstcmce (Fig. 209) is a lenticular disk of fibro- cartilage,
interposed between the adjacent surfaces of the bodies of the vertebrae, from the
Fig. 209. — Vertical Section of two Vertebrae and their Ligaments, from the Lumbar Region.
ANTERIOR
COMMON
Lie
POSTERIOR
COMMON
axis to the sacrum, and forming the chief bond of connection between these
bones. These disks vary in shape, size, and thickness, in different parts of the
spine. In shape they accurately correspond with the surfaces of the bodies
between which they are placed, being oval in the cervical and lumbar regions,
and circular in the dorsal. Their size is greatest in the lumbar region. In
thickness they vary not only in the different regions of the spine, but in different
parts of the same region : thus, they are uniformly thick in the lumbar region ;
tliickest, in front, in the cervical and lumbar regions which are convex forwards;
and behind, to a slight extent, in the dorsal region. They thus contribute, in a
great measure, to the curvatures of the spine in the neck and loins; whilst the
concavity of the dorsal region is chiefly due to the shape of the bodies of the
vcrtcbra3. The intervertebral disks form about one-fonrth of the spinal column,
exclusive of tlic first two vcrtebrns; tliey are not equally distributed, however,
between the various bones; the dorsal portion of the spine having, in proportion
to its length, a much smaller quantity than in the cervical and lumbar regions,
which necessarily gives to the latter parts greater pliancy and freedom of move-
ment. The intervertebral disks are adlicrent, by their surfaces, to the adjacent
parts of the bodies of the vcrtebrie ; and by their circumference are closely
connected in front to tlic anterior, and l)oliind to the posterior common ligament;
wliilst, in the dorsal region, they are connected laterally, by means of the inter-
OF THE SPINE. ||| 287
articular ligament, to the lieads of those ribs wliich articulate with two ver-
tebrae ; they, consequently, form part of the articular cavities in which the
heads of those bones are received.
The intervertebral substance is composed, at its circumference, of laminse of
fibrous tissue and iibro-cartilage ; and, at its centre, of a soft, elastic, pulpy
matter. The laminse are arranged concentrically one within the other, with
their edges turned towards the corresponding surfaces of the vertebrae, and con-
sist of alternate plates of fibrous tissue and fibro-cartilage. These plates are not
quite vertical in their direction, those near the circumference being curved out-
wards and closely approximated ; whilst those nearest the centre curve in the
opposite direction, and are somewhat more widely separated. The fibres of
which each plate is composed, are directed, for the most part, obliquely from
above downwards ; the fibres of an adjacent plate have an exactly opposite
arrangement, varying in their direction in every layer ; whilst in some few they
are horizontal. This laminar arrangement belongs to about the outer half of
each disk, the central part being occupied by a soft, pulpy, highly elastic sub-
stance, of a yellowish color, which rises up considerabl}^ above the surrounding
level, when the disk is divided horizontally. This substance presents no con-
centric arrangement, and consists of white fibrous tissue, with cells of variable
shape and size interspersed. The pulpy matter, which is especially well devel-
oped in the lumbar region, is separated from immediate contact with the verte-
brae by the interposition of thin plates of cartilage.
2. Ligaments connecting the Lamina.
Ligamenta Subflava.
The Ligamenta Subflava (Fig. 209) are interposed between the laminae of the
vertebrae, from the axis to the sacrum. They are most distinct when seen from
the interior of the spinal canal ; when viewed from the outer surface, they appear
short, being overlapped by the laminse. Each ligament consists of two lateral
portions, which commence on each side at the root of either articular process,
and pass backwards to the point where the laminae converge to form the spinous
process, where their margins are thickest, and separated by a slight interval,
filled up with areolar tissue. These ligaments consist of yellow elastic tissue,
the fibres of which, almost perpendicular in direction, are attached to the ante-
rior surface of the margin of the lamina above, and to the posterior surface, as
well as to the margin of the lamina below. In the cervical region, they are
thin in texture, but very broad and long ; they become thicker in the dorsal
region: and in the lumbar acquire very considerable thickness. Their highly
elastic property serves to preserve the upright posture, and to assist in resuming
it, after the spine has been flexed. These ligaments do not exist between the
occiput and atlas, or between the atlas and axis.
3. Ligaments connecting the Aeticulae Jeocesses.
The Capsular Ligaments (Fig. 211) are thin and loose ligamentous sacs, at-
tached to the contiguous margins of the articulating processes of each vertebra,
through the greater part of their circumference, and completed internally by
the ligamenta subflava. They are longer and more loose in the cervical than
in the dorsal or lumbar regions. The capsular ligaments are lined on their inner
surface by synovial membrane.
4. Ligaments connecting the Spinous Peocesses.
Interspinous. Supraspinous.
The Interspinous Ligaments (Fig. 209), thin and membranous, are interposed
between the spinous processes in the dorsal and lumbar regions. Each ligament
288 ARTICULATIONS.
extends from tlie root to near tlie summit of eacli spinous process, and connects
together their adjacent margins. Tliey are narrow and elongated in the dorsal
region, broader, quadrilateral in form, and thicker in the lumbar region.
The Supraspinous Liyament is a strong fibrous cord, which connects together
the apices of the spinous processes from the seventh cervical to the spine of the
sacrum. It is .thicker and broader in the lumbar than in the dorsal region, and
intimately blended, in both situations, with the neighboring aponeuroses. The
most superficial fibres of this ligament connect three or four vertebrae ; those
deeper seated pass between two or three vertebr£e ; , whilst the deepest connect
the contiguous extremities of neighboring vertebrte.
5, Ligaments connecting the Teansveese Peocesses.
Intertransverse.
The Intertransverse Ligaments consist of a few thin scattered fibres, interposed
between the transverse processes. They are generally wanting in the cervical
region ; in the dorsal, they are rounded cords ; in the lumbar region they are
thin and membranous.
Actions. The movements permitted in the spinal column are, Flexion, Exten-
sion, Lateral movement, Circumduction, and Eotation.
In Flexion^ or movement of the spine forwards, the anterior common ligament
is relaxed, and the intervertebral substances are compressed in front ; while the
posterior common ligament, the ligamenta subflava, and the inter- and supra-
spinous ligaments, are stretched, as well as the posterior fibres of the interver-
tebral disks. The interspaces between the laminae are widened, and the inferior
articular processes of the vertebras above glide upwards, upon the articular pro-
cesses of the vertebrge below. Flexion is the most extensive of all the move- "
ments of the spine.
In Extension.^ or movement of the spine backwards, an exactly opposite dispo-
sition of the parts takes place. This movement is not extensive, being limited
by the anterior common ligament, and by the approximation of the spinous
processes.
Flexion and extension are most free in the lower part of the lumbar, and in
the cervical regions; extension in the latter region being greater than flexion,
the reverse of which is the case in the lumbar region. These movements are
least free in the middle and upper part of the back.
In Lateral Movement.^ the sides of the intervertebral disks are compressed, the
extent of motion being limited by the resistance offered by the surrounding liga-
ments, and by the approximation of the transverse processes. This movement
may take place in any part of the spine, but is most free in the neck and loins.
Circnrnduction is very limited, and is produced merely by a succession of the
preceding movements.
Rotation is produced by the twisting of the intervertebral substances; this,
although only slight between any two vertebrEe, produces a great extent of
movement, when it takes place in the whole length of the spine, the front of the
column being turned to one or the other side. This movement takes place only
to a slight extent in the neck, but is more free in the lower part of the dorsal
and lumbar regions.
It is thus seen that the cervical region enjoys the greatest extent of each variety
of movement, flexion and extension especially being very free. In the dorsal
region^ especially at its upper part, the movements are most limited; flexion,
extension, and lateral molion hiking ])lace only to a slight extent.
Jl. Airncri-A'i'iox of TirK Atlas with the Axis.
The articulation of tlic anterior arcli of the atlas witli tlie odontoid process
forms a lateral ginglymus joint, whilst that between the articulating processes
OF THE ATLAS WITH THE AXIS.
289
of the two bones forms a double artlirodia. The ligaments which connect these
bones are, the
Two Anterior Atlo-axoid. Transverse.
Posterior Atlo-axoid. Two Capsular.
Of the Tico Anterior Atlo-axoid Ligaments (Fig. 210), the more superficial is
a rounded cord, situated in the middle line ; it is attached, above, to the tubercle
Fig. 210.— Occipito-atloid and Atlo-axoid Ligaments. Front Yiew.
1\
r CAPSULAR LICT
CAPSULAR LI C -^ &
on the anterior arch of the atlas ; below, to the base of the odontoid process and
body of the axis. The deeper ligament is a membranous layer, attached, above,
to the lower border of the anterior arch of the atlas ; below, to the base of the
odontoid process, and body of the axis. These ligaments are in relation, in
front, with the Recti antici majores.
The Posterior Atlo-axoid Ligament (Fig. 211) is a broad and thin membranous
layer, attached, above, to the lower border of the posterior arch of the atlas ;
below, to the upper edge of the lamina of the axis. This ligament supplies the
place of the ligamenta subflava, and is in relation, behind, vfith the Inferior
oblique muscles.
The Transverse Ligament'^ (Figs. 212, 213) is a thick and strong ligamentous
band, which arches across the ring of the atlas, and serves to retain the odontoid
process in firm connection with its anterior arch. This ligament is flattened
from before backwards, broader and thicker in the middle than at either ex-
tremity, and firmly attached on each side of the atlas to a small tubercle on
the inner surface of its lateral mass. As it crosses the odontoid process, a small
fasciculus is derived from its upper and lower borders; the former passing
upwards, to be inserted into the basilar process of the occipital bone; the latter,
downwards, to be attached to the root of the odontoid process ; hence, the whole
ligament has received the name of cruciform. The transverse ligament divides
' It has been found necessary to describe the transverse ligament with those of the atlas and
axis ; but the student must remember that it is really a portion of the mechanism by which the
movements of the head on the spine are regulated ; so that the connections between the atlas
and axis ought always to be studied together with those between the latter bones and the skull.
19
290
ARTICULATIONS.
tlie ring of the atlas into two unequal parts : of tliese, tlie posterior and larger
serves for tlie transmission of the cord and its membranes; the anterior and
Fig. 211. — Occipito-axoid and Atlo-axoid Ligaments. Posterior View.
A.rcFi foTjoaasaae of'Veri'fliraZA.Ta
FisT. 212. — Articulation between Odontoid Process and Atlas.
smaller contains the odontoid process. Since the lower border of the space
between the anterior arch of the atlas and the transverse ligament is smaller
than the upper (because the transverse ligament embraces firmly the narrow
neck of the odontoid ])rocess), this process is retained in firm connection with
the atlas when all the other ligaments have been divided.
The Capsular L'UjaTnents are two thin and loose capsules, connecting the
articular surfaces of the atlas and axis, the fibres being strongest on the anterior
and external pjirt of the articulation.
There ura frmr Synovial Mnnhrancs in this jirlicnlation ; one lining tlie inner
surface of each of the capsular ligaments; one between the anterior surface of
the odontoid process and the anterior arch of tlie atlas; and one between the
OF THE SPINE AND CRANIUM.
291
posterior surface of the odontoid process and the transverse ligament. The
latter often communicates with those between the condyles of the occipital bone
and the articular surfaces of the atlas.
Fig. 213. — Occipito-axoid and Alto-axoid Ligaments. Posterior Yiew, obtained by removing
the arches of the Vertebrae aud. the posterior part of the sliuU.
t/ir Vcrllcal /lorftert
!>/ ODONTOID Lie:?
CAPSULAR Lie : &
TuOiO \Siirioifial /ncn)hranj
CAPSUL/IR LICT &
t\%0\ D [ Sijnovtal me/nirune
-J«*J
Actions. This joint is capable of great mobility, and allows the rotation of
the atlas (and, with it, of the cranium) upon the axis, the extent of rotation
being limited by the odontoid ligaments.
Articulations of the Spine with the Cranium.
The ligaments connecting the spine with the cranium may be divided into
two sets, those connecting the occipital bone with the atlas, and those connecting
the occipital bone w^ith the axis.
III. Articulation of the Atlas with the Occipital Bone.
This articulation is a double arthrodia. Its ligaments are the
Two Anterior Occipito-atloid.
Posterior Occipito-atloid.
Two Lateral Occipito-atloid.
Two Capsular.
Of the Two Anterior Ligaments (Fig. 210), the superficial is a strong, narrow,
rounded cord, attached, above, to the basilar process of the occiput ; below, to
the tubercle on the anterior arch of the atlas : the deeper ligament is a broad
and thin membranous layer which passes between the anterior margin of the
foramen magnum above, and the whole length of the upper border of the ante-
rior arch of the atlas below. This ligament is in relation, in front, with the Eecti
antici minores ; behind, with the odontoid ligaments.
The Posterior Occipito-atJoid Ligament (Fig. 211) is a very broad but thin
membranous lamina, intimately blended with the dura mater. It is connected.
292 ARTICULATIOInS.
above, to tlie posterior margin of tlie foramen magnnm ; "below, to tlie upper
border of tlie posterior arcli of the atlas. This ligament is incomplete at each
side, and forms, with the superior intervertebral notch, an opening for the pas-
sage of the vertebral arterj and sub-occipital nerve. It is in relation, behind,
with the Eecti postici minores and Obliqui superiores ; in front, with the dura
mater of the spinal canal, to which it is intimately adherent.
The Lateral Ligaments are strong fibrous bands, directed obliquely upwards
and inwards, attached above to the jugular process of the occipital bone ; below,
to the base of the transverse process of the atlas.
The Capsular Ligaments surround the condyles of the occipital bone, and con-
nect them with the articular surfaces of the atlas ; they consist of thin and loose
capsules, which inclose the synovial membrane of the articulation. The synovial
membranes between the occipital bone and atlas communicate occasionally
with that between the posterior surface of the odontoid process and transverse
ligaments.
Actions. The movements permitted in this joint are flexion and extension,
which give rise to the ordinary forward or backward nodding of the head,
besides slight lateral motion to one or the other side. When either of these
actions is carried ^ beyond a slight extent, the whole of the cervical portion of the
spine assists in its production. According to Cruveilhier, there is a slight
motion of rotation in this joint.
IV. Aeticulation of the Axis with the Occipital Boxe.
Occipito-axoid. Three Odontoid.
To expose these ligaments, the spinal canal should be laid open by removing
the posterior arch of the atlas, the laminse and spinou.s process of the axis,
and the portion of the occipital bone behind the foramen magnum, as seen in
Fig. 213.
The Occipito-axoid Ligament (Apparatus ligamentosus colli) is situated at the
upper part of the front surface of the spinal canal. It is a broad and strong
ligamentous band, which covers the odontoid process and its ligaments, and
appears to be a prolongation upwards of the posterior common ligament of the
spine. It is attached, below, to the posterior surface of the body of the axis,
and, becoming expanded as it ascends, is inserted into the basilar groove of the
occipital bone, in front of the foramen magnum.
Relations. By its anterior surface, it is intimately connected with the trans-
verse ligament, by its posterior surface with the dura mater. By cutting this
ligament across, and turning its ends aside, the transverse and odontoid liga-
ments are exposed.
The Odontoid or Chech Ligaments are strong, rounded, fibrous cords, which
arise one on either side of the apex of the odontoid process, and, passing obliquely
upwards and outwards, are inserted into the rough depressions on the inner side
of the condyles of the occipital bone. In the triangular interval left between
these ligaments and the margin of the foramen magnum, a third strong liga-
mentous band (ligamcntum suspensorium) may be seen, which passes almost
perpendicularly from the apex of the odontoid process to the anterior margin of
the foramen, being intimately blended with the anterior occipito-atloid ligament,
and upper fasciculus of the transverse ligament of the atlas.
Actions. The odontoid ligaments serve to limit the extent to which rotation
of the cranium may be carried ; hence they have received the name of chech
ligaments.
Y. Temporo-maxillary Articulation,
This is an arthrodial joint; the parts entering into its formation are, on each
Bide, the anterior part of the glenoid cavity of the temporal bone and the
TEMPO RO-M AXILLARY.
293
eminentia articularis above ; with tlie condyle of the lower jaw below. The
ligaments are the following :
External Lateral. Stylo-maxillarj.
Internal Lateral. Capsular.
Interarticnlar Fibro-cartilage.
Fig. 214. — Temporo-maxillary Articulatioa. External View.
Fig. 215. — Temporo-maxillary Articulation.
Inlernal View.
The External Lateral Ligament (Fig. 214) is a short, thin, and narrow fasci-
culus attached above to the outer surface of the zygoma and to the rough
tubercle on its lower border ; below,
to the outer surface and posterior
border of the neck of the lower jaw.
This ligament is broader above
than below; its fibres are placed
parallel with one another, and
directed obliquely downwards and
backwards. Externally, it is
covered by the parotid gland and
by the integument. Internally, it
is in relation with the interarticu-
lar fibro-cartilage and the synovial
membrane.
The Internal Lateral Ligament
(Fig. 215) is a long, thin, and loose
band, which is attached above to
the spinous process of the sphenoid
bone, and becoming broader as it
descends, is inserted into the inner
margin of the dental foramen. Its
outer surface is in relation above
with the External pterygoid mus-
cle ; lower down it is separated from
the neck of the condyle by the in-
294
ARTICULATIONS.
ternal maxillary artery ; and still more inferiorly tlie inferior dental vessels and
nerve separate it from tlie ramus of the jaw. Internally, it is in relation -vvitli
tlie Internal pterygoid.^
The Stylo-maxillary Ligament is a thin aponeurotic cord, which extends from
near the apex of the styloid process of the temporal bone, to the angle and
posterior border of the ramus of the lower jaw, between the Masseter and In-
ternal pterygoid muscles. This ligament separates the parotid from the sub-
maxillary gland, and has attached to its inner side part of the fibres of origin
of the Stylo-glossus muscle. Although usually classed among the ligaments
of the jaw, it can only be considered as an accessory in the articulation.
Along with the stylo-maxillary ligament, may be described the stylo-hyoid liga-
m,ent^ although it is in no way connected with the functions of the lower jaw.
This is a fibrous cord, which continues the styloid process down to the hyoid
bone, being attached to the tip of the former and the small cornu of the latter.
It is often more or less ossified.
The Capsular Ligament forms a thin and loose ligamentous capsule, attached
above to the circumference of the glenoid cavity and the articular surface
immediately in front ; below, to the neck of the condyle of the lower jaw. It
consists of a few thin scattered fibres, and can hardly be considered as a distinct
ligament ; it is thickest at the back part of the articulation.
The Inter articular Fihro-cartilage (Fig. 216) is a thin plate of an oval form,
jDlaced horizontally between the condyle of the jaw and the glenoid cavity.
Its upper surface is concave from
Fig. 216 — Yertical Section of Temporo-raaxillarj before backwards, and a little con-
Articulation. yq^ transversely, to accommodate
itself to the form of the glenoid
cavity. Its under surface, where
it is in contact with the condyle, is
concave. Its circumference is con-
nected externally to the external
lateral ligament ; internally, to the
capsular ligament; and in front to
the tendon of the External ptery-
goid muscle. It is thicker at its
circumference, especially behind,
than at its centre, where it is some-
times perforated. The fibres of
which it is composed have a con-
centric arrangement, more apparent
at the circumference than at the centre. Its surfaces are smooth, and divide
the joint into two cavities, each of which is furnished with a separate synovial
membrane. When the fibro-cartilage is perforated, the synovial membranes
are continuous with one another.
The Synovial Memhranes, two in number, are placed one above, and the other
below the fibro-cartilage. The upper one, the larger and looser of the two, is
continued from the margin of the cartilage covering the glenoid cavity and
eminentia articularis, over the upper surface of the fibro-cartilage. The lower
one is interposed between the under surface of the fibro-cartilage and the con-
dyle of the jaAV, being prolonged downwards a little further behind than in front.
The Nerves of tliis joint are derived from the auriculo-temporal and masseteric
branches of the inferior maxillary.
Actions. The movements permitted in this articulation are very extensive.
Thus, the jaw may be depressed or elevated, or it may be carried forwards or
backwards, or from side to side. It is l)y the altcnialion of these movements
' Dr. Tfiinipliry dcscribcH tlic intornal porlion of the capsular liiraiiiont. Kcparatcly, as llic short
internal lateral lif.'-atiicMit ; and it certainly sccnis as deserving of a separate description as the
external lateral litranient is.
RIBS WITH VERTEBRAE.
295
performed in succession, tliat a kincl'of rotatory movement of tlie lower jaw upon
the upper takes place, wliich materially assists in the mastication of the food.
If the movement of depression is carried only to a slight extent, the condyles
remain in the glenoid cavities, their anterior part descending only slightly ; but
if the depression is considerable, the condyles glide from the glenoid fosste on to
the articular eminences, carrying with them the interarticular fibro-cartilages.
When this movement is carried to too great an extent, as, for instance, during a
convulsive yawn, dislocation of the condyle into the zj^gomatic fossa may occur ;
the interarticular cartilage being carried forwards, and the capsular ligament
ruptured. When the jaw is elevated, after forced de|Dression, the condyles and
fibro-cartilages are carried backwards into their original position. When the
jaw is carried horizontally forwards and backwards, or from side to side, a
horizontal gliding movement of the fibro-cartilages and condyles U23on the
glenoid cavities takes place in the corresponding direction.
VI. Articulation of the Eibs with the Yertebr^.
The articulation of the ribs with the vertebral column may be divided into
two sets : 1. Those which connect the heads of the ribs with the bodies of the
vertebree ; 2. Those which connect the necks and tubercles of the ribs with the
transverse processes.
1. Articulations between the Heads of the Eibs and the Bodies
OP the Vertebra. (Fig. 217.)
These constitute a series of ginglymoid joints, formed by the articulations of
the heads of the ribs with the cavities on the contiguous margins of the bodies
of the dorsal vertebrae, connected together by the following ligaments : —
Anterior Costo- vertebral or Stellate.
Capsular.
Interarticular.
The Anterior Costo-vertehral or Stellate Ligament connects the anterior part
of the head of each rib with the sides of the bodies of two vertebrae, and the
intervertebral disk between them. It consists of three flat bundles of liga-
mentous fibres, which
radiate from the anterior Fig. 217.— Costo-vertebral and Costo-transverse Articulatious.
part of the head of the Anterior View,
rib. The superior fasci-
culus passes upwards to
be connected with the
body of the vertebra
above; the inferior one
descends to the body of
the vertebra below ; and
the middle one, the
smallest and least dis-
tinct, passes horizontally
inwards to be attached
to the intervertebral
substance.
Relations. In front,
with the thoracic ganglia
of the sympathetic, the
pleura, and on the right
side, with the vena
azygos major; behind,
with the interarticular
ligament and synovial
membranes.
Xirwer Syiwi/ial
296 ARTICULATIONS.
In tlie first rib, wliicli articulates witli a' single vertebra only, tliis ligament
does not present a distinct division into three fasciculi ; its superior fibres, how-
ever, pass to be attached to the body of the last cervical vertebra, as well as to
the body of the vertebra with which the rib articulates. In the tenth, eleventh,
and twelfth ribs also, which likewise articulate with a single vertebra, the
division does not exist ; but the upper fibres of the ligament, in each case, are con-
nected with the vertebra above, as well as that with which the ribs articulate.
The Capsular Ligament is a thin and loose ligamentous bag, which surrounds
the joint between the head of the rib and the articular cavity formed by the
junction of the vertebree. It is very thin, firmly connected with the anterior
ligament, and most distinct at the upper and loAver parts of the articulation.
The Inter articular Ligament is situated in the interior of the joint. It con-
sists of a short band of fibres, flattened from above downwards, attached by one
extremity to the sharp crest on the head of the rib, and by the other to the
intervertebral disk. It divides the joint into two cavities, which have no com-
munication with one another, but are each lined by a separate synovial mem-
brane. In the first, tenth, eleventh, and twelfth ribs, the interarticular ligament
does not exist ; consequently, there is but one synovial membrane.
Actions. The movement permitted in these articulations are limited to eleva-
tion, depression, and a slight amount of movement forwards and backwards.
The mobility, however, of the different ribs varies ^erj much. The first rib is
almost immovable, excepting in deep inspiration. The movement of the second
rib is also not very extensive. In the other ribs, their mobility increases suc-
cessively down to the last two, which are very movable. The ribs are generally
more movable in the female than in the male.
2. Akticulatioxs of the Necks and Tubeecles of the Eibs with the •
Teansveese Peocesses. (Fig. 218.)
The ligaments connecting these parts are — •
Anterior Costo-transverse.
Middle Costo-transverse (Interosseous).
Posterior Costo-transverse.
Capsular.
The Anterior Costo-transverse Ligament is a broad and strong band of fibres,
attached below to the sharp crest on the upper border of the neck of each rib,
and passing obliquely upwards and outwards, to the lower border of the trans-
verse process immediately above. It is broader below than above, broader and
thinner between the lower ribs than between the upper, and more distinct in
front than behind. This ligament is in relation, in front, with the intercostal
vessels and nerves; behind, with the Longissimus dorsi. Its internal border
completes an aperture formed between it and the articular processes, through
which pass the posterior branches of the intercostal vessels and nerves. Its
external horder is continuous with a thin aponeurosis, which covers the External
intercostal muscle.
Thcj^r.s^ and last rihs have no anterior costo-transverse ligament.
The Middle Costo-transverse or Interosseous Ligament consists of short, but
strong, fibres, whicli pass between the rough surface on the posterior part of the
neck of each rib, and the anterior surface of the adjacent transverse process. In
order fully to expose this ligament, a horizontal section should be made across
the transverse process and corresponding part of the rib; or the rib may be
forcibly sc])aratcd from the tj-ansversc process, and its fibres put on the stretch.
In the eleventli, and tii-elfih rihs, this ligament is quite rudiinentarv.
The Posterior Costo-transverse Ligament is a short, but ihiclc and strong, fas-
ciculus, which passes obliquely from the summit of the transverse process to the
rough non-articular portion of the tubercle of the ivib. ^J'liis ligament is shorter
EIBS WITH THE STERNUM.
297
and more oblique in tlie npper tlian in tlie lower ribs. Those corresponding to
the superior ribs ascend, and those of the inferior ones slightly descend.
Fig. 218. — Costo-transverse Articulation. Seen from above.
ANTr.RIOR COSTO-TRANSVERSE LI CT OrVIDED
MIDDLE COSTO-TRANSVERSE
INTEROSSEOUS
POSTERIOR COSTO-TRANSVEBSE LICT
CAPSULAR (■<2MBK.'vlM«
In the eleventh and twelfth rihs, this ligament is wanting.
The articular portion of the tubercle of the rib, and adjacent transverse process,
form an arthrodial joint, provided with a thin Capsular ligament attached to
the circumference of the articulating surfaces, and enclosing a small synovial
inemhrane.
In the eleventh and tivelfth rihs^ this articulation is wanting.
Actions. The movement permitted in these joints is limited to a slight gliding
motion of the articular surfaces one upon the other.
VII. Articulation of the Cartilages of the Eibs with the Sternum, etc.
(Fig. 219.)
The articulations of the cartilages of the true ribs with the sternum are arthro-
dial joints. The ligaments connecting them are —
Anterior Costo-sternal.
Posterior Costo-sternal.
Capsular.
The Anterior Costo-sternal Ligament is a broad and tnin mernbranous band
that radiates from the inner extremity of the cartilages of the true ribs to the
anterior surface of the sternum. It is composed of fasciculi, which pass in dif-
ferent directions. The superior fasciculi ascend obliquely, the inferior pass
obliquely downwards, and the middle fasciculi horizontally. The superficial fibres
of this ligament are the longest ; they intermingle with the fibres of the liga-
ments above and below them, with those of the opposite side, and with the tendi-
nous fibres of origin of the Pectoralis major ; forming a thick fibrous membrane,
which covers the surface of the sternum. This is more distinct at the lower
than at the upper part.
The Posterior Costo-sternal Ligament, less thick and distinct than the anterior,
is composed of fibres which radiate from the posterior surface of the sternal end
of the cartilages of the true ribs, to the posterior surface of the sternum, becom-
ing blended with the periosteum.
298
ARTICULATIONS.
Tlie Capsular Ligament surrounds tile joints formed between tlie cartilages of
tlie true ribs and tbe sternum. It is very tliin, intimately blended Avitb the
anterior and posterior ligaments, and strengthened at the upper and lower part
of the articulation by a few fibres, which pass from the cartilage to the side of
the sternum, ' These ligaments protect the synovial membranes.
Fig. 219. — Costo-sternal, Costo-xiphoid, and Intercostal Articulations. Anterior Yiew.
77io symn'icil caidtccs exposetl
by a vcrta:al section oj tJio Sterimm h CariUa^ea
auiitiTULouji 7idth iStCor7iuiii,
I NTCR-ARTICULAR llCf
liv a3 jiiwiM/a'L iii^mora.tuia
SC-n^le Sfyitoii'nl
Mentbi'ane
Synovial Memlranes. The cartilage of i\\G first rih is directly continuous with
the sternum, without any synovial membrane. The cartilage of the second rih
is connected with the sternum by means of an intcrarticular ligament, attached
by one extremity to the cartilage of the second rib, and by the otlier extremity
to the cartilage wliich unites tlie first and second pieces of the sternum. This
articulation is provided with two synovial membranes. That of the third rib
has also two synovial membranes; and tluit of the fourth, fifth, sixth, and
seventh, each a single synovial membrane. Tims tlicre are eight synovial cavi-
LIGAMENTS OF THE STERNUM. 299
ties on eacli side in tlie articulations between tlie costal cartilages of tlie true
ribs and the sternum. They may be demonstrated by removing a thin section
from the anterior surface of the sternum and cartilages, as seen in the figure.
After middle life, the articular surfaces lose their polish, become roughened, and
the synovial membranes appear to be wanting. In old age, the articulations do
not exist, the cartilages of most of the ribs becoming continuous with the ster-
num. The cartilage of the seventh rib, and occasionally also that of the sixth, is
connected to the anterior surface of the ensiform appendix, by a band of liga-
mentous fibres, which varies in length and breadth in different subjects. It is
called the costo-xiphoid ligmnent.
Actions. The movements which are permitted in the costo-sternal articula-
tions, are limited to elevation and depression; and these only to a slight extent.
Articulations of the Cartilages of the Eibs with each other
(Interchojstdral). (Fig. 219.)
The cartilages of the sixth, seventh, and eighth ribs articulate, by their lower
borders, with the corresponding margin of the adjoining cartilages, by means of
a small, smooth, oblong-shaped facet. Each articulation is enclosed in a thin
capsular ligament, lined by synovial membrane, and strengthened externally and
internally by ligamentous fibres (intercostal ligaments), which pass from one
cartilage to the other. Sometimes the cartilage of the fifth rib, more rarely
that of the ninth, articulates, by its lower border, with the adjoining cartilage
by a small oval facet ; more frequently they are connected together by a few
ligamentous fibres. Occasionally, the articular surfaces above mentioned are
wanting.
Articulations of the Eibs with their Cartilages (Costo-chondral).
(Fig. 219.)
The outer extremity of each costal cartilage is received into a depression in
the sternal end of the ribs, and held together by the periosteum.
VIII. Ligaments of the Sternum.
The first and second pieces of the sternum are united by a layer of cartilage,
which rarely ossifies, except at an advanced period of life. These two segments
are connected by an anterior and posterior ligament. (See on this head p. 207
note.)
The anterior sternal ligament consists of a layer of fibres, having a longitudinal
direction ; it blends with the fibres of the anterior costo-sternal ligaments on
both sides, and with the aponeurosis of origin of the Pectoralis major. This
ligament is rough, irregular, and much thicker at the lower than at the upper
part of the bone.
The posterior sternal ligament is disposed in a somewhat similar manner on
the posterior surface of the articulation.
IX. Articulation of the Pelvis with the Spine.
The ligaments connecting the last lumbar vertebra with the sacrum are simi-
lar to those which connect the segments of the spine with each other, viz. : — 1.
The contniuation downwards of the anterior and posterior common ligaments.
2. The intervertebral substance connecting the flattened oval surfaces of the
two bones, and forming an amphiarthrodial joint, 3. Ligamenta subflava, con-
necting the arch of the last lumbar vertebra with the posterior border of the
sacral canal. 4. Capsular ligaments connecting the articulating processes and
forming a double arthrodia. 5. Interspinous and supraspinous ligaments.
300
ARTICULATIONS.
The two proper ligaments connecting the pelvis witli tlie spine are the lumbo-
sacral and ilio-Iumbar.
The Lumho-sacral Li(jament (Fig. 220) is a short, thick, triangular fasciculus,
which is connected above to the lower and front part of the transverse process
of the last lumbar vertebra, passes obliquely outwards, and is attached below to
the lateral surface of the base of the sacrum, becoming blended with the ante-
rior sacro-iliac-ligament. This ligament is in relation in front with the Psoas
muscle.
The llio-lumhar Ligament (Fig. 220) passes horizontally outwards from the
apex of the transverse process of the last lumbar vertebra, to the crest of the
Fig. 220. — Articulations of Pelvis and Hip. Anterior View.
*t of enTnmuiifCiilui'nt
of psoas 3i. lUIACUS
ilium immediately in front of the sacro-iliao articulation. It is of a triangular
form, thick and narrow internally, broad and thinner externally. It is in rela-
tion, in front, with the Psoas muscle ; behind, with the muscles occupying the
vertebral groove ; above, with the Quadratns lumborum.
X. Aeticulations of tite Pelvis.
The ligaments connecting the bones of the pelvis with each other may be
divided into four groups: — 1. Those connecting the sacrum and ilium. 2. Those
])assing between the sacrum and ischium. 3. Those connecting the sacrum and
coccyx. 4. Those between the two pul)ic bones.
1. Articulation of the Sacrum and Ilium.
The sacro-iliac articulation is an amphinrthrodial joint, formed between the
lateral surfaces of the sacrum and iliuin. The anterior or auricular portion of
each articular surface is covered with a thin plate of cartilage, thicker on the
SACRUM AND ISCHIUM. 301
sacrum than on tlie ilium. The surfaces of these cartilages in the adult are
rough and irregular, and separated from one another by a soft yellow pulpy
substance. At an early period of life, occasionally in the adult, and in the
female during pregnancy, they are smooth, and lined by a delicate synovial
membrane. The ligaments connecting these surfaces are the anterior and
posterior sacro-iliac.
The Anterior Sacro-iliac Ligament (Fig. 220) consists of numerous thin liga-
mentous bands, which connect the anterior surfaces of the sacrum and ilium.
The Posterior Sacro-iliac (Fig. 221) is a strong interosseous ligament, situated
in a deep depression between the sacrum and ilium behind, and forming the
chief bond of connection between those bones. It consists of numerous strong
fasciculi, which pass between the bones in various directions. Three of these
are of large size ; the tivo superior^ nearly horizontal in direction, arise from the
first and second transverse tubercles on the posterior surface of the sacrum, and
are inserted into the rough uneven surface at the posterior part of the inner
surface of the ilium. The third fasciculus, oblique in direction, is attached by
one extremity to the third transverse tubercle on the posterior surface of the
sacrum, and by the other to the posterior superior spine of the ilium ; it is some-
times called the oblique sacro-iliac ligament.
2. Ligaments passing between the Sacrum and Ischium. (Fig. 221.)
The Great Sacro-sciatic (Posterior).
The Lesser Sacro-sciatic (Anterior),
The Great or Posterior Sacro-sciatic Ligament is situated at the lower and
back part of the pelvis. It is thin, flat, and triangular in form; narrower in
the middle than at the extremities ; attached by its broad base to the posterior
inferior spine of the ilium, to the fourth and fifth transverse tubercles on the
sacrum, and to the lower part of the lateral margin of that bone and the coccyx ;
passing obliquely downwards, outwards, and forwards, it becomes narrow and
thick ; and at its insertion into the inner margin of the tuberosity of the ischium,
it increases in breadth, and is prolonged forwards along the inner margin of the
ramus, forming what is known as the falciform ligament. The free concave
edge of this ligament has attached to it the obturator fascia, with which it forms
a kind of groove protecting the internal pudic vessels and nerve. One of its
surfaces is turned towards the perineum, the other towards the Obturator
internus muscle.
The posterior surface of this ligament gives origin, by its whole extent, to
fibres of the Gluteus maximus. Its a,nterioT surface is united to the lesser sacro-
sciatic ligament. Its superior horder forms the lower boundary of the lesser
sacro-sciatic foramen. Its loiver horder forms part of the boundary of the peri-
neum. It is pierced by the coccygeal branch of the sciatic artery.
The Lesser or Anterior Sacro-sciatic Ligament^ much shorter and smaller than
the preceding, is thin, triangular in form, attached by its apex to the spine of
the ischium, and internally, by its broad base, to the lateral margin of the
sacrum and coccyx, anterior to the attachment of the great sacro-sciatic ligament,
with which its fibres are intermingled.
It is in relation, anteriorly^ with the Coccygeus muscle ; posteriorly^ it is covered
by the posterior ligament, and crossed by the internal pudic vessels and nerve.
Its superior horder forms the lower boundary of the great sacro-sciatic foramen;
its inferior horder^ part of the lesser sacro-sciatic foramen.
These two ligaments convert the sacro-sciatic notches into foramina. The
superior or great sacro-sciatic foramen is bounded, in front and above, by the
posterior border of the os innominatum; behind, by the great sacro-sciatic liga-
ment ; and below, by the lesser ligament. It is partially filled up, in the recent
state, by the Pyriformis muscle. Above this muscle, the gluteal vessels and
302
ARTICULATIONS.
superior gluteal nerve emerge from the pelvis ; and below it> tlie ischiatic vessels
and nerves, the internal pudic vessels and nerve, and the nerve to the Obturator
internus. The inferior or lesser sacro-sciatic foramen is bounded, in front, by
Fig. 221. — Articulations of Pelvis and Hip. Posterior View.
ANTER [OR OR LESSER
SACRO-SCIATIC LICIT
the tuber ischii ; above, by the spine and lesser ligament ; behind, by the greater
ligament. It transmits the tendon of the Obturator internus muscle, its nerve,
and the internal pudic vessels and nerve.
3. Aeticulation of the Sacrum and Coccyx.
This articulation is an amphiarthrodial joint, formed between the oval surface
ou the apex of the sacrum, and the base of the coccyx. It is analogous to the
joints between the bodies of the vertebree, and is connected by similar ligaments.
They are the
Anterior Sacro-coccygeal.
Posterior Sacro-coccygcal .
Interposed Fibro-cartilage.
The Anterior l^acro-cocnyfical TA(jaw,oMt consists of a few irregular fibres, which
descend from the anterior surface of the sacrum to tlie front of the coccyx,
becoming blcnflcd with the periosteum.
The Poslerior Sacro-coccj/fjeal Ligament is a flat band of ligamentous fibres, of
a pearly tint, which arises from the margin of the lower orifice of tlie sacral
canal, and descends to be inserted into the posterior surface of the coccyx. This
ligament completes the lower anrl back part of the sacral canal. Its superficial
fibres arc much longer. thai) llic (l(!ep-seated ; the hatter extend from the apex
of the sacrum to tlie upper cornua of the coccvx. Tliis ligament is in relation in
i'ront with the arachnoid membrane of the sacral canal, a portion of the sacrum
SYMPHYSIS PUBIS.
303
and almost tlie whole of tlie posterior surface of the coccyx; behind, with the
Gluteus maximus.
A Fihro-cartilage is interposed between the contiguous surfaces of the sacrum
and coccyx ; it differs from that interposed between the bodies of the vertebras
in being thinner, and its central part more firm in texture. It is somewhat
thicker in front and behind than at the sides. Occasionally, a synovial mem-
brane is found when the coccyx is freely movable, which is more especially the
case during pregnancy.
The different segments of the coccyx are connected together by an extension
downwards of the anterior and posterior sacro-coccygeal ligaments, a thin
annular disk of fibro-cartilage being interposed between each of the bones. In
the adult male, all the pieces become ossified ; but in the female, this does not
commonly occur until a later period of life. The separate segments of the
coccyx are first united, and at a more advanced age the joint between the sacrum
and coccyx is obliterated
Actions. The movements which take place between the sacrum and coccyx,
and between the different pieces of the latter bone, are slightly forwards and
backwards ; they are very limited. Their extent increases during pregnancy.
4. Articulation" of the Pubes. (Fig. 222.)
The articulation between the pubic bones is an amphiarthrodial joint, formed
by the junction of the two oval articular surfaces of the ossa pubis. The articu-
lar surface has been described above under the name of symphysis.^ and the same
name is given to the joint. The ligaments of this articulation are the
Anterior Pubic. Posterior Pubic.
Superior Pubic. Subpubic.
Interposed Fibro-cartilage.
The Anterior Puhic Ligament consists of several superimposed layers, which
pass across the front of the articulation. The superficial fibres pass obliquely
from one bone to the other, decussating and forming an interlacement with the
fibres of the aponeurosis of the External oblique muscle. The deep fibres pass
transversely across the symphysis, and are blended with the fibro-cartilage.
Fig. 222. — Vertical Section of the Symphysis Pubis.
Titv Fihro-CaTtilacjinoiis plntes
Znie-rmediate daatic tissue
SynoiHol eavify at umxr &• hack pari-
Made near its Posterior Surface.
The Posterior Pubic Ligament consists of a few thin, scattered fibres, which
unite the two pubic bones posteriorly.
The Superior Puhic Ligament is a band of fibres, which connects together the
two pubic bones superiorly.
304 ARTICULATIONS
The Suhpubic Ligament is a tliick, triangular arcli of ligamentous fibres,
connecting together the two pubic bones below, and forming the upper boundary
of the pubic arch. Above, it is blended with the interarticular iibro-cartilage ;
laterally, with the rami of the pubes. Its fibres are of a yellowish color, closely
connected, and have an arched direction.
The Interposed Fihro-cartilage consists of two oval-shaped plates, one covering
the surface of each symphysis pubis. They vary in thickness in different
subjects, and project somewhat beyond the level of the bones, especially behind.
The outer surface of each plate is firmly connected to the bone by a series of
nipple-like processes, which accurately fit within corresponding depressions on
the osseous surface. Their opposed surfaces are connected in the greater part
of their extent, by an intermediate elastic fibrous tissue ; and by their circum-
ference to the various ligaments surrounding the joint. An interspace is left
between the plates at the upper and back part of the articulation, where the
fibrous tissue is deficient, and the surface of the fibro-cartilage is lined by epi-
thelium. This space is found at all periods of life, both in the male and female ;
but it is larger in the latter, epecially during pregnancy, and after parturition.
It is most frequently limited to the upper and back part of the joint, but it
occasionally reaches to the front, and may extend the entire length of the carti-
lage. This structure may be easily demonstrated, by making a vertical section
of the symphysis pubis near its post-erior surface.
The Obturator Ligam.ent is more properly regarded as analogous to the
muscular fascige, with which it will therefore be described.
ARTICULATIONS OF THE UPPEE EXTREMITY.
The articulations of the Upper Extremity may be arranged in the following
groups : — I. Sterno-clavicular articulation. II. Scapulo-clavicular articulation.
III. Ligaments of the Scapula. lY. Shoulder-joint. Y. Elbow-joint. YI.
Radio-ulnar articulations. YII. Wrist-joint. YIII. Articulation of the Carpal
bones. IX. Carpo-metacarpal articulations. X. Metacarpo-phalangeal articu-
lations. XL Artie ul-ations of the Phalanges.
I. Steeno-clavicular Articulation. (Fig. 223.)
The Sterno-clavicular is an arthrodial joint. The parts entering into its forma-
tion are the sternal end of the clavicle, the upper and lateral part of the first
piece of the sternum, and the cartilage of the first rib. The articular surface
of the clavicle is much larger than that of the sternum, and invested with a
layer of cartilage,^ which is considerably thicker than that on the latter bone.
The ligaments of this joint are the
Anterior Sterno-clavicular. Interclavicular.
Posterior Sterno-clavicular. Costo-clavicular (rhomboid).
Interarticular Fibro-cartilage.
Tlie Anterior /^lerno-clavicuj.a.r Ligament is a broad band of fibres, which covers
the anterior surface of the articulation, being attached, above, to the upper and
front part of the inner extremity of the clavicle; and, passing obliquely down-
wards and inwards, is attjicliod, below, to the front and ujipcr part of the first
piece of the sternum. Tliis ligament is covered in front by the_sternal_ pcn-tion
of the Sterno-clcido-mastoid and the integument; behind, it is in relation with
the interarticular fibro-cartilage and the two synovial membranes.
The L^oHlarior Sterno-clamcidar Ligament is a similar band of fibres, which
' Apr'or(1in[r to T.riirl), llu- storrKil cud of llio claviclo is ('ovorod hy a tissue, which is rathor
fibrous than cartilaginous in structure.
STERNO-CLAVICULAR JOINT,
305
covers tlie posterior surface of the articulation, being attached, above, to the pos-
terior part of the inner extremity of the clavicle ; and which, passing obliquely
downwards and inwards, is connected, below, to the posterior and upper part of
Fig:. 223. — Sterno-clavicular Articulation. Anterior View.
the sternum. It is in relation, in front, with the interarticular fibro-cartilage
and synovial membranes; behind, with the Sterno-hyoid and Sterno-thyroid
muscles.
The Interclavicular Ligament is a flattened band, which varies considerably
in form and size in different individuals; it passes from the upper part of the
inner extremity of one clavicle to the' other, and is closely attached to the upper
margin of the sternum. It is in relation, in front, with the integument ; behind,
with the Sterno-thyroid muscles.
The Costo-clavicular Ligament [rhomhoid) is short, fiat, and strong : it is of a
rhomboid form, attached, below, to the upper and inner part of the cartilage of
the first rib : it ascends obliquely backwards and outwards, and is attached above
to the rhomboid depression on the under surface of the clavicle. It is in rela-
tion, in front, with the tendon of origin of the subclavius ; behind, with the sub-
clavian vein.
The Interarticular Fihro-cartilage is a flat and' nearly circular disk, interposed
between the articulating surfaces of the sternum and clavicle. It is attached,
above, to the upper and posterior border of the clavicle ; below, to the cartilage
of the first rib, at its junction with the sternum : and by its circumference to the
anterior and posterior sterno-clavicular ligaments. It is thicker at the circum-
ference, especially its upper and back part, than at its centre, or below. It divides
the joint into two cavities, each of which is furnished with a separate synovial
membrane ; when the fibro-cartilage is perforated, which not unfrequently occurs,
the synovial membranes communicate.
Of the two Synovial Membranes found in this articulation, one is reflected from
the sternal end of the clavicle, over the adjacent surface of the fibro-cartilage,
and cartilage of the first rib ; the other is placed between the articular surface
of the sternum and adjacent surface of the fibro-cartilage ; the latter is the more
loose of the two. The}^ seldom contain much synovia.
Actions. This articulation is the centre of the movements of the shoulder,
and admits of motion in nearly every direction — upwards, downwards, back-
wards, forwards, as well as circumduction. " The movements attendant on eleva-
tion and depression of the shoulder take place between the clavicle and the
interarticular ligament ; the bone rotating upon the ligament on an axis drawn
from before backwards through its own articular facet. When the shoulder is
20
306 ARTICULATIONS.
moved forwards and backwards, the clavicle, with the interarticular ligament,
rolls to and fro on the articnlar surface of the sternum, revolving, with a slightly
sliding movement, round an axis drawn nearly vertically through the sternum.
In the circumduction of the shoulder, which is compounded of these two move-
ments, the clavicle revolves upon the interarticular cartilage, and the latter,
with the clavicle, rolls upon the sternum."^
II. SCAPULO-CLAVICULAR ARTICULATION. (Fig. 224.)'
The Scapulo -clavicular is an arthrodial joint, formed between the outer extre-
mity of the clavicle, and the upper edge of the acromion process of the scajDula.
Its ligaments are the
Superior Acromio-clavicular.
Inferior Acromio-clavicular.
( Trapezoid
Coraco- clavicular I and
( Conoid.
Interarticular I'ibro-cartilage.
The Superior Acromio-clavicular Li(j amentia a broad band, of a quadrilateral
form, which covers the superior part of the articulation, extencliiig between the
upper part of the outer end of the clavicle, and the adjoining part of the acromion.
It is composed of parallel fibres, which interlace with the ajDoneurosis of the
Trapezius and Deltoid muscles; below, it is in contact with the interarticular
fibro-cartilage and synovial membranes.
The Inferior Acromio-clavicular Ligam,ent^ somewhat thinner than the pre-
ceding, covers the under part of the articulation, and is attached to the adjoining
surfaces of the two bones. It is in relation, above, with the interarticular fibro-
cartilage (when it exists) and the synovial membranes ; below, with the tendon
of the Supraspinatus. These two ligaments are continuous with each other in
front and behind, and form a complete capsule around the joint.
The Goraco-clavicular Ligament serves to connect the clavicle with the coracoid
process of the scapula. It consists of two fasciculi, called the trapezoid and
conoid ligaments.
The trapezoid ligament, the anterior and external fasciculus, is broad, thin, and
nuadrilateral: it is placed obliquely between the coracoid process and the clavicle.
It is attached, below, to the upper surface of the coracoicl process ; above, to the
oblique line on the under surface of the clavicle. Its anterior border is free;
its posterior border is joined with the conoid ligament, the two forming by their
junction a projecting angle.
The conoid ligam.ent, the posterior and internal fasciculus, is a dense band of
fibres, conical in form, the base being turned upwards, the summit downwards.
It is attached by its apex to a rough depression at the base of the coracoid pro-
cess, internal to the preceding; above, by its expanded base, to the conoid
tubercle on the under surface of the clavicle, and to a line proceeding internally
from it for half an inch. Those ligaments are in relation, in front, with the
Subclavius; behind, with the Trapezius: they serve to limit rotation of the
scapula forwards and backwards.
The Inter articular Fihro- cartilage is most frequently absent in this articula-
tion. When it exists, it generally only partially separates the articular surfaces,
and occupies the upper part of the articulation. More rarely, it completely
separates the joint into two cavities.
There are tv^o Synovial Memliranes when a complete interarticular cartilage
exists; more frcfpicntly there is only one synovial membrane.
Actions. The movcincnis of this articulation are of two kinds. 1. A gliding
' III MriiitY, On the Human Skeleton, p. 402.
LIGAMENTS OF THE SCAPULA.
307
motion of tlie articular end of tlie clavicle on tlie acromion. 2. Eotation of the
scapula forwards and backwards upon the clavicle, the extent of this rotation
being limited bj the two portions of the coraco-clavicular ligament.
Fig. 224.— The Left Shoulder-joint, Scapulo-cUivicuhn- Articulations,
and proper Ligaments of Scapula.
The scapulo-clavicular joint has important functions in the movements of the
upper extremity. It has been well pointed out by Prof Humphry, that if there
had been no joint between the clavicle and scapula the circular movement of
the scapula on the ribs (as in throwing both shoulders back or forward) would
have been attended with a greater alteration in the direction of the shoulder
than is consistent with the free use of the arm in such positions, and it would
have been impossible to give a blow straight forward with the full force of the
arm, that is to say, with the combined force of the scapula, arm, and forearm.
"This joint," as he happily says, "is so adjusted as to enable either bone to turn
in a hinge-like manner upon a vertical axis drawn through the other, and it
permits the surfaces of the scapula, like the baskets in a round-about swing, to
look the same way in every position, or nearly so." Again, when the whole
arch formed by the clavicle and scapula rises and falls (in elevation or depres-
sion of the shoulders), the joint between these two bones enables the scapula
still to maintain its lower part in contact with the ribs.
III. Peoper Ligaments of the Scapula. (Fig. 224.)
The proper ligaments of the scapula are, the
Coraco-acromial. Transverse.
The Coraco-acromial Ligament is a broad, thin, flat band, of a triangular
shape, extended transversely above the upper part of the shoulder-joint, between
308 ARTICULATIONS.
tlie coracoid and acromion processes. It is attaclied, by its apex, to tlie summit
of the acromion just in front of tlie articular surface for the clavicle ; and by its
broad base, to the whole length of the outer border of the coracoid process. Its
jDosterior fibres are directed obliquely backwards and outwards, its anterior
fibres transversely. This ligament completes the vault formed by the coracoid
and acromion processes for the protection of the head of the humerus. It is in
relation, above, with the clavicle and under surface of the Deltoid ; below, with
the tendon of the Supraspinatus muscle, a bursa being interposed. Its anterior
border is continuous with a dense cellular lamina that passes beneath the Deltoid
upon the tendons of the Supraspinatus and Infraspinatus muscles.
The Transverse or Coracoid Ligament converts the suprascapular notch into a
foramen. It is a thin and flat fasciculus, narrower at the middle than at the
extremities, attached, by one end, to the base of the coracoid process, and, by
the other, to the inner extremity of the scapular notch. The suprascapular
nerve passes through the foramen ; the suprascapular vessels above it.
lY. Shoulder-joint. (Fig. 22-i.)
The Shoulder is an enarthrodial or ball-and-socket joint. The bones entering
into its formation, are the large globular head of the humerus, received into the
shallow glenoid cavity of the scapular, an arrangement which permits of very
considerable movement, whilst the joint itself is protected against displacement
by the strong ligaments and tendons which surround it, and above by an arched
vault, formed by the under surface of the coracoid and acromion processes, and
the coraco-acromial ligament. The articular surfaces are covered by a layer of
cartilage : that on the head of the humerus is thicker at the centre than at the
circumference, the reverse being the case in the glenoid cavity. The ligaments
of the shoulder are, the
Capsular. Coraco -humeral.
Glenoid.^
The Capsular Ligament completely encircles the articulation ; being attached,
above, to the circumference of the glenoid cavity beyond the glenoid ligament ;
below, to the anatomical neck of the humerus, approaching nearer to the articu-
lar cartilage above than in the rest of its extent. It is thicker above than
below, remarkably loose and lax, and much larger and longer than is necessary
to keep the bones in contact, allowing them to be separated from each other
more than an inch, an evident provision for that extreme freedom of movement
which is peculiar to this articulation. Its external surface is strengthened,
above, by the Supraspinatus ; above and internally, by the coraco-humeral
ligament ; below, by the long head of the Triceps ; externally, by the tendons
of the Infraspinatus and Teres minor; and internally, by the tendon of the Sub-
scapularis. The capsular ligament usually presents three openings; one at its
inner side, below the coracoid process, partially filled up by the tendon of the
Subscapularis ; it establishes a communication between the synovial membrane
of the joint and a bursa beneath the tendon of that muscle. The second, Avhich
is not constant, is at the outer part, where a communication sometimes exists
between the joint and a bursal sac belonging to the Infraspinatus muscle. The
tliird is seen in the lower border of the ligament, between the Iavo tuberosities,
f(jr the passage of the long tendon of the Biceps muscle.
The Coraco-] tiLineral or Accessory Tjigament is a broad band which strengthens
the upper and inner part of the capsular ligament. It arises from tlio outer
border of the coracoid process, and passes obliquely downwards and outwa-rds
' 'I'lic Iniif,'' tcMiddii of (iriLnii of 1he Biceps muscle also acts as one of llic li^'anionls of tin's
joint, fciec the ob.sorvation.s on p. 284, on ihu fuuclion of tlic muscles passing over nioie ihaii one
joint.
SHOULDER-JOINT. 309
to the front of tlie great tuberosity of the humerus, being blended with the
tendon of the Supraspinatus muscle. . This ligament is intimately united to the
capsular in the greater part of its extent.
The Glenoid Ligament is a firm fibrous band attached round the margin of
the glenoid cavity. It is triangular on section, the thickest portion being fixed
to the circumference of the cavity, the free edge being thin and sharp. It is
continuous above with the long tendon of the Biceps muscle, which bifurcates
at the upper part of the cavity into two fasciculi, encircling the margin of the
glenoid cavity and uniting at its lower part. This ligament deepens the cavity
for articulation, and protects the edges of the bone. It is lined by the synovial
membrane.
The Synovial Membrane lines the margin of the glenoid cavity and the fibro-
cartilaginous rim surrounding it; it is then reflected over the internal surface
of the capsular ligament, covers the lower part and sides of the neck of the-
humerus, and is continued a short distance over the cartilage covering the head
of the bone. The long tendon of the Biceps muscle which passes through the
capsular ligament, is inclosed in a tubular sheath of synovial membrane, which
is reflected upon it at the point where it perforates the capsule, and is continued
around it as far as the summit of the glenoid cavity. The tendon of the Biceps
is thus enabled to traverse the articulation, but is not contained in the interior
of the synovial cavity. The synovial membrane communicates with a large
bursal sac beneath the tendon of the Subscapularis, by an opening at the inner
side of the capsular ligament; it also occasionally communicates v/ith another
bursal sac, beneath the tendon of the Infraspinatus, through an orifice at its
outer part. A third bursal sac, which does not communicate with the joint, is.
placed between the under surface of the deltoid and the outer surface of the
capsule.
The Muscles in relation with the joint are, above, the Supraspinatus; below,
the long head of the Triceps ; internally, the Subscapularis ; externally, the
Infraspinatus, and Teres minor ; within, the long tendon of the Biceps. The
Deltoid is placed most externally, and covers the articulation on its outer side,
as well as in front and behind.
The Arteries supplying the joint are articular branches of the anterior and
posterior circumflex, and suprascapular.
The Nerves are derived from the circumflex and suprascapular.
Actions. The shoulder-joint is capable of movement in every direction, for-
wards, backwards, abduction, adduction, circumduction, and rotation.
The most striking peculiarities in this joint are : 1. The large size of the head
of the humerus in comparison with the depth of the glenoid cavity, even when
supplemented by the glenoid ligament. 2. The looseness of the capsule of the
joint. 3. The intimate connection of the capsule with the muscles attached to the
head of the humerus. 4. The peculiar relation of the biceps tendon to the joint.
It is in consequence of the relative size of the two articular surfaces that the
joint enjoys so free movement in every possible direction. When these move-
ments of the arm are arrested in the shoulder -joint by the contact of the bony
surfaces, and by the tension of the corresponding fibres of the capsule, together
with that of the muscles acting as accessory ligaments, they can be carried con-
siderably further by the movements of the scapula, involving, of course, motion
at the coraco- and sterno- clavicular joints. These joints are therefore to be
regarded as accessory structures to the shoulder-joint.^ The extent of these
movements of the scapula is very considerable, especially in extreme elevation
of the arm, which movement is best accomplished when the arm is thrown
somewhat forward, since the articular surface of the humerus is broader in the
middle than at either end, especially the lower, so that the range of elevation
directly forward is less, and that directly backward still more restricted. The
• See pp. 306, 307..
310 ARTICULATIONS.
great width of tlie central portion of tlie humeral head allows of very free
horizontal movement when the arm is raised to a right angle, in which move-
ment the arch formed by the acromion, the coracoid process, and the coraco-
acromial ligament, constitutes a sort of supplemental articular cavity for the
head of the bone.
The looseness of the capsule is so great that the arm will fall about an inch
from the scapula when the muscles are dissected from the capsular ligament,
and an opening made in it to remove the atmospheric pressure. The movements
of the joint, therefore, are not regulated by the capsule, so much as by the
surrounding muscles and by the pressure of the atmosphere, an arrangement
Avhich "renders the movements of the joint much more easy than they would
otherwise have been, and permits a swinging pendulum-like vibration of the
limb, when the muscles are at rest." (Humphry.) The fact, also, that in all
ordinary positions of the joint the capsule is not put on the stretch, enables the
arm to move freely in all directions. Extreme movements are checked by the
tension of appropriate portions of the capsule, as well as by the interlocking of
the bones. Thus it is said that "abduction is checked by the contact of the
great tuberosity with the upper edge of the glenoid cavity, adduction, b}^ the
tension of the coraco-humeral ligament." (Beaunis et Bouchard.)
The intimate union of the tendons of the four short muscles with the capsule
converts these muscles into elastic and spontaneously acting ligaments of the
joint, and it is regarded as being also intended to prevent the folds into which
all portions of the capsule would alternately fall in the varjang positions of the
joint from being driven between the bones by the pressure of the atmosphere.
The peculiar relations of the biceps tendon to the shoulder-joint appear to
subserve various purposes. In the first place by its connection with both the
shoulder and elbow, the muscle harmonizes the action of the two joints, and'
acts as an elastic ligament in all positions, in the manner previously adverted
to.^ Next it strengthens the upper part of the articular cavity, and prevents
the head of the humerus from being pressed up against the acromion process,
when the deltoid contracts, instead of forming the centre of motion in the glenoid
cavity. By its passage along the bicipital groove it assists to render the head
of the humerus steady in the various movements of the arm and forearm. To
these offices Prof. Humphry adds, that "it assists the supra- and infraspinatus
muscles to cause the head of the humerus to revolve in the glenoid cavity when
the arm is raised from the side, and that it holds the head of the humerus firmly
in contact with the glenoid cavity, and prevents its slipping over the lower
edge of the cavity or being displaced by the action of the latissimus dorsi and
pectoralis major when the arm is raised from the side, as in climbing and man}-
other movements."
Y. Elbow-joint.
The Elbow is a ginglymus or hinge joint. The bones entering into its forma-
tion are the trochlear surface of the humerus, which is received in the greater
sigmoid cavity of the ulna, and admits of the movements peculiar to this joint,
those of flexion and extension, Avhilst the ciiji-shaped depression on the head of
the radius articulates with the lesser, or radial, head of the humerus, and the
circumference of the head of the radius with the lesser sigmoid cavity of the
ulna, allowing of the mcwcment of rotation of the radius on the ulna, the chief
action of the superior radio-ulnar articulation. The articular surfaces are
covered witli a thin layer of carlilngc, and connc^cted together by the following
ligaments: —
Anterior. Internal Lateral.
Posterior. External Lateral.
' Sec p. 284.
ELBOW-JOINT.
311
Figf.
225. Left Elbow-joint, showing An-
terior and Internal Ligaments.
The orbicular ligament of the upper radio-ulnar articulation must also be
I'eckoned among the ligaments of the elbow.
The Anterior Ligament (Fig. 225) is a broad and thin fibrous layer, which
covers the anterior surface of the joint. It is attached to the front of the
humerus immediately above the coronoid fossa ; below, the anterior surface of
the coronoid process of the ulna and orbicular ligament, being continuous on
each side with the lateral ligaments. Its superficial or oblique fibres pass from
the inner condyle of the humerus outwards to the orbicular ligament. The
middle fibres, vertical in direction, pass from the upper part of the coronoid
depression, and become blended with the preceding. A third, or transverse set,
intersect these at right angles. This liga-
ment is in relation, in front, with the Bra-
chialis anticus ; behind, with the synovial
membranes.
The Posterior Ligar)ient (Fig. 226) is a
thin and loose membranous fold, attached,
above, to the lower end of the humerus,
immediately above the olecranon fossa;
below, to the margin of the olecranon.
The superficial or transverse fibres pass
between the adjacent margins of the ole-
cranon fossa. The deeper portion consists
of vertical fibres, which pass from the upper
part of the olecranon fossa to the margin
of the olecranon. This ligament is in rela-
tion, behind, with the tendon of the Triceps
and the Anconeus ; in front, with the syno-
vial membrane.
The Internal Lateral Ligament (Eig. 225)
is a thick triangular band, consisting of
two distinct portions, an anterior and pos-
terior. The anterior portion^ directed ob-
liquely forwards, is attached, above, by its
apex, to the front part of the internal con-
dyle of the humerus ; and, below, by its
broad base, to the inner margin of the coro-
noid process. The posterior portion^ also
of triangular form, is attached, above, by
its apex, to the lower and back part of the
internal condyle ; below, to the inner mar-
gin of the olecranon. This ligament is in
relation, internally, with the Triceps and
Flexor carpi ulnaris muscles, and the ulnar
nerve.
The External Lateral Ligament (Fig. 226)
is a short and narrow fibrous fasciculus, less distinct than the internal, attached,
above,- to the external condyle of the humerus ; below, to the orbicular liga-
ment, some of its most posterior fibres passing over that ligament, to be inserted
into the outer margin of the ulna. This ligament is intimately blended with
the tendon of origin of the Supinator brevis muscle.
The Synovial Membrane is very extensive. It covers the margin of the arti-
cular surface of the humerus, and lines the coronoid and olecranon fossae on that
bone ; from these points, it is reflected over the anterior, posterior, and lateral
ligaments ; and forms a pouch between the lesser sigmoid cavity, the internal
surface of the orbicular ligament, and the circumference of the head of the
radius.
312
ARTICULATIONS,
Fig. 226.— Left Elbow-joint, showing The Muscles in relation witli tlie joint are in
Posterior and External Ligaments. ^^.^^^^ ^lie Brachialis anticns; behind, the Tri-
ceps and Anconeus ; externally, the Supinator
brevis, and the common tendon of origin of the
Extensor muscles ; internally, the common ten-
don of origin of the Flexor muscles, and the
Flexor carpi ulnaris, with the ulnar nerve.
The Arteries supplying the joint are derived
from the communicating branches between the
superior profunda, inferior profunda, and an-
astomotic branches of the brachial, with the
anterior, posterior, and interosseus recurrent
branches of the ulnar, and the recurrent branch
of the radial. These vessels form a complete
chain of inosculation around the joint.
The Nerves are derived from the ulnar, as it
passes between the internal condyle and the ole-
cranon ; and a few filaments from the musculo-
cutaneous.
Actions. The elbow-joint comprises three
different portions : viz., the joint between the
ulna and humerus, that between the head of the
radius and the humerus, and the superior radio-
ulnar aa'ticulation, described below. All these
articular surfaces are invested by a common
synovial membrane, and the movements of the
whole joint should be studied together. The-
combination of the movements of flexion and
extension of the forearm with those of prona-
tion and supination of the hand, which is en-
sured by the two being performed at the same
joint, is essential to the accuracy of the various minute movements of the hand.
The portion of the joint between the ulna and humerus is a simple hinge-joint,
and allows of movements of flexion and extension only. The shape of the
trochlear surface of the humerus, with its prominences and depressions accurately
adapted to the opposing surfaces of the olecranon, prevents any lateral movement.
In the ordinary position assumed by the humerus, when resting on the promi-
nent internal condyle, this direct movement of flexion carries the hand inwards,
towards the chest and mouth.
The joint between the head of the radius and the capitellum or radial head of
the humerus is an arthrodial joint. The bony surfaces would of themselves con-
stitute an enarthrosis and allow of movement in all directions, were it not for
the orbicular ligament by which the head of the radius is bound down firmly to
the sigmoid cavity of the ulna, and which prevents any separation of the two
bones laterally. It is to the same ligament that the head of the radius owes its
security from dislocation, which would otherwise constantly occur, as a conse-
quence of the shallowness of the cup-like surface on the head of the radius. In
fact, but for this ligament, the tendon of the biceps would be liable to pull the
head of the radius out of the joint.^ In complete extension, the head of the radius
glides so far back on the outer condyle that its edge is plainly felt at the back
of the joint.
In combination with any position of flexion or extension, the head of the
radius can be rotated in the upper radio-uhiar joint, carrying the hand with it.
The hand is articulated to the lower surface of the radius only, and the concave
or sigmoid surface on the lower end of the radius travels round the lower end
Ilunipliry, op. cit. p. 419.
RADIO-ULNAE. 313
of the ulna. The latter bone is excluded from the wrist-joint (as will be seen
in the sequel) by the triangular tibro-cartilage. Thus, rotation of the head of
the radius round an axis which passes through the external condyle of the
humerus, imparts circular movement to the hand through a very considerable
arc. If it is necessary to turn the hand iipwards and downwards without
changing its place (as in using a corkscrew), this circular movement is obviated
by rapid instinctive compensating changes in the position of the elbow.
VL Eadio-ulnar Aeticulations.
The articulation of- the radius with the ulna is effected by ligaments, which
connect together both extremities as well as the shafts of these bones. They
may, consequently, be subdivided into three sets : 1. The superior radio-ulnar,
which is a portion of the elbow-joint; 2, the middle radio-ulnar; and, 3, the
inferior radio-ulnar articulations.
1. Superior Eadio-ulnar Articulation",
This articulation is a lateral ginglymus. The bones entering into its forma-
tion are the inner side of the circumference of the head of the radius rotating
within the lesser sigmoid cavity of the ulna. These surfaces are covered with
cartilage, and invested with a duplicature of synovial membrane, continuous
with that which lines the elbow-joint. Its only ligament is the annular or orbi-
cular.
The Orbicular Ligament (Fig. 226) is a strong, flat band of ligamentous fibres,
which surrounds the head of the radius, and retains it in firm connection with
the lesser sigmoid cavity of the ulna. It forms about three-fourths of a fibrous
ring, attached by each end to the extremities of the lesser sigmoid cavity, and
is broader at the upper part of its circumference than below, by which means
the head of the radius is more securely held in its position. Its outer surface is
strengthened by the external lateral ligament of the elbow, and affords origin to
part of the Supinator brevis muscle. Its inner surface is smooth, and lined by
synovial membran^e.
Actions. The movement which takes place in this articulation is limited to
rotation of the head of the radius within the orbicular ligament, and upon the
lesser sigmoid cavity of the ulna; rotation forwards being called pronation;
rotation backwards, supination.
2. Middle Eadio-ulnar ArticulatiojST,
The interval between the shafts of the radius and ulna is occupied by two
ligaments.
Oblique, Interosseous,
The Ohlique or Round Ligament (Fig. 225) is a small, round fibrous cord,
which extends obliquely downwards and outwards, from the tubercle of the ulna
at the base of the coronoid process, to the radius a little below the bicipital
tuberosity. Its fibres run in the opposite direction to those of the interosseous
ligament ; and, it appears to be placed as a substitute for it in the upper part of
the interosseous interval. This ligament is sometimes wanting.
The Interosseous Membrane is a broad and thin plane of aponeurotic fibres,
descending obliquely downwards and inwards, from the interosseous ridge on
the radius to that on the ulna. It is deficient above, commencing about an inch
beneath the tubercle of the radius ; is broader in the middle than at either ex-
tremity ; and presents an oval aperture just above its lower margin for the
passage of the anterior interosseous vessels to the back of the forearm. This
ligament serves to connect the bones, and to increase the extent of surface for
314
ARTICULATIONS.
the attacliment of the deep muscles. Between its upper border and the oblique
ligament an interval exists, through which the posterior interosseous vessels
pass. Two or three fibrous bands are occasionally found on the posterior sur-
face of this membrane, which descend obliquely from the ulna towards the radius,
and which have consequently a direction contrary to that of the other fibres.
It is in relation, in front^ by its upper three-fourths with the Flexor longus
poUicis on the outer side, and with the Flexor profundus digitornm on the inner,
Iving upon the interval between which are the anterior interosseous vessels and
nerve, by its lower fourth with the Pronator quadratus ; hehind^ with the Supi-
nator brevis. Extensor ossis metacarpi pollicis. Extensor primi internodiipollicis,
Extensor secundi internodii pollicis. Extensor indicis ; and, near the wrist, with
the anterior interosseous artery and posterior interosseous nerve.
3. Inferioe Radio-ulnar Articulation.
This is a lateral ginglymus, formed by the head of the ulna received into the
sigmoid cavity at the inner side of the lower end of the radius. The articular
surfaces are covered by a thin layer of cartilage, and connected together by the
following ligaments :—
Anterior Radio-ulnar.
Posterior Eadio-ulnar.
Triangular luterarticular Fibro-cartilage.
The Anterior Radio-ulnar Ligament (Fig. 227) is a narrow band of fibres, ex-
tending from the anterior margin of the sigmoid cavity of the radius to the
anterior surface of the head of the ulna.
Fig. 227. — Ligaments of Wrist and Hand. Anterior View.
lIJF-ERlOn RADlO-ULrjAR ARTICS
WniST-JOIIMT
CAnPAL ARTICS?
CARPO-HnETACARPA!- AnTlC !!
The Posterior Radio-ulnar Ligament (Fig. 22-^) extends between similar points
on tlie posterior surface of tlic artionlation.
The Triangular Fihrn-mrtilage (Fig. 220, ]-). 820) is ])laccd transversely iKMioalli
l!ic hoad of the ulna, binding the lower end of lliis bone and the radins lii-nily
together. Its cirfinrnfcrencels thicker than its centre, which is thin and occa-
sionally perforated. It is attached by its apex to a depression wliicli separates
WRIST-JOINT.
315
the styloid process of tlie ulna from tlie liead of that bone ; and, by its base,
Avhich is thin, to the prominent edge of the radius, which separates the sigmoid
cavity from the carpal articulating surface. Its margins are united to the liga-
ments of the wrist-joint. Its up^jer surface^ smooth and concave, is contiguous
Fig. 228.^Ligaments of Wrist and liand. Posterior View.
Ca TV 0 -Metaca rjiaZ
with the head of the ulna; its under surface.^ also concave and smooth, with the
cuneiform bone. Both surfaces are lined by a synovial membrane : the upper
surface by one peculiar to the radio-ulnar articulation ; the under surface, by
the synovial membrane of the wrist.
The Synovial Membrane (Fig. 229) of this articulation has been called, from
its extreme looseness, the meinhrana sacciformis ; it covers the margin of the
articular surface of the head of the ulna, and where reflected from this bone on
to the radius, forms a very loose cul-de-sac; from the radius, it is continued over
the upper surface of the iibro- cartilage. The quantity of synovia which it con-
tains is usually considerable. When the fibro-cartilarge is perforated, the
synovial membrane is continuous with that which lines the wrist.
Actions. The arrangement in the inferior radio-ulnar articulation is just the
reverse of that between the two bones above ; motion is limited to rotation of
the radius round the head of the ulna ; rotation forwards being {QTirnd pronation^
rotation backwards suiy'ination. In pronation, the sigmoid cavity glides forward
on the articular edge of the ulna ; in supination, it rolls in the opposite direction,
the extent of these movements being limited by the anterior and posterior liga-
ments.
VII. Radio- CAEPAL or Wrist- joint.
The Wrist presents some of the characters of an enarthrodial joint, but is
more correctly regarded as an arthrodia. The parts entering into its formation
are, the lower end of the radius, and under surface of the triangular iuterarticu-
lar fibro- cartilage above ; and the scaphoid, semilunar, and cuneiform bones
below. The articular surfaces of the radius and interarticular fibro-cartilage
form a transversely elliptical concave surface. The surface of the radius is
subdivided into two parts by a line extending from before backwards ; and
these, together with the interarticular cartilage, form three facets, one for each
316 AETICULATIONS.
carpal bone. The tliree carpal bones are connected together, and form a con-
vex surface, wliick is received into tlie concavity above mentioned. All the
bony surfaces of the articulation are covered with cartilage, and connected to-
gether by the following ligaments : —
External Lateral. Anterior.
Internal Lateral. Posterior.
The External Lateral Ligament {radio-carpal) (Fig. 227) extends from the
summit of the styloid process of the radius to the outer side of the scaphoid,
some of its fibres being prolonged to the trapezium and annular ligament.
The Lnternal Lateral Ligament (ulno-carpal) is a rounded cord, attached, above,
to the extremity of the styloid process of the ulna : and dividing below into
two fasciculi, which are attached, one to the inner side of the cuneiform bone,
the other to the pisiform bone and annular ligament.
The Anterior Ligament is a broad membranous band, consisting of three fasci-
culi, attached, above, to the anterior margin of the lower end of the radius, its
styloid process, and the ulna ; its fibres pass downwards and inwards, to be
inserted into the palmar surface of the scaphoid, semilunar, and cuneiform
bones. This ligament is perforated by numerous apertures for the passage of
vessels, and is in relation, in front, with the tendons of the Flexor profundus
digitorum and Flexor longus poUicis ; behind, with the synovial membrane of
the wrist-joint.
The Posterior Ligament (Fig. 228), less thick and strong than the anterior, is
attached, above, to the posterior border of the lower end of the radius ; its fibres
pass obliquely downwards and inwards to be attached to the dorsal surface of
the scaphoid, semilunar, and cuneiform bones, being continuous with those of
the dorsal carpal ligaments. This ligament is in relation, behind, with the
extensor tendons of the fingers ; in front, with the sjmovial membrane of the
wrist.
The Synovial Ifemhrane (Fig. 229) lines the under surface of the triangular
interarticular fibro-cartilage above ; and is reflected on the inner surface of the
ligaments just described.
Relations. The wrist-joint is covered in front by the flexor, and behind by
the extensor tendons ; it is also in relation with the radial and ulnar arteries.
The Arteries supplying the joint are the anterior and posterior carpal branches
of the radial and ulnar, the anterior and posterior interosseous, and some ascend-
ing branches from the deep palmar arch.
The Nerves are derived from the ulnar and posterior interosseous.
Actions. The movements permitted in this joint are flexion, extension, abduc-
tion, adduction, and circumduction. It is totally incapable of rotation, one of
the characteristic movements in true enarthrodial joints. Its action will be
further studied with, those of the carpus, with which they are combined,
YIII. Articulations of the Carpus.
These articulations may be subdivided into three sets.
1. The Articulations of the First Eow of Carpal Bones.
2. The Articulations of the Second E(^w of Car]tal Bones.
3. T]ic Articulations of the Two Rows with each other.
1. AirrifTLATTONS OF n^TTE First Row of Carpal Bones.
These are arthrodial joints. Tlio articnhir surHices arc covered with cartilage,
and conncdcd 1()g(;thcr by the following ligaments: —
Two Dorsal. Two Pahnar.
Two Interosseous.
OF THE CAEPUS. 317
Tlie Dorsal Ligaments are placed transversely beliind tlie bones of tlie first
row ; tliey connect the scaphoid and semilunar, and the semilunar and cuneiform.
The Palmar Ligaments connect the scaphoid and semilunar, and the semilunar
and cuneiform bones ; they are less strong than the dorsal, and placed very deep
under the anterior ligament of the wrist.
The Lnterosseous Ligaments (Fig. 229) are tv/o narrow bundles of fibrous tissue,
connecting the semilunar bone, on one side with the scaphoid, on the other with
the cuneiform. They close the upper part of the interspaces between the
scaphoid, semilunar, and cuneiform bones, their upper surfaces being smooth,
and lined by the synovial membrane of the wrist-joint.
The articulation of the pisiform with the cuneiform is provided with a sepa-
rate synovial membrane, protected by a thin capsular ligament. There are also
two strong fibrous fasciculi, which connect this bone to the unciform and the
base of the fifth metacarpal bone (Fig. 227).
2. Articulations op the Second Eow of Carpal Bones.
These are also arthrodial joints. The articular surfaces are covered with car-
tilage, and connected by the following ligaments:^
Three Dorsal. Three Palmar.
Two Interosseous.
The three Dorsal Ligaments extend transversely from one bone to another on
the dorsal surface, connecting the trapezium with the trapezoid, the trapezoid
with the OS magnum, and the os magnum with the unciform.
The three Palmar Ligaments have a similar arrangement on the palmar surface.
The two Lnterosseous Ligaments^ much thicker than those of the first row, are
placed one on each side of the os magnum, connecting it with the trapezoid
externally, and the unciform internally. The former is less distinct than the
latter.
3. Articulations of the Two Rows of Carpal Bones with each other.
The articulations between the two rows of the carpus consist of a joint in
the middle, formed by the reception of the head of the os magnum into a cavity
formed by the scaphoid and semilunar bones, and of an arthrodial joint on each
side, the outer one formed by the articulation of the scaphoid with the trapezium
and trapezoid, the internal one by the articulation of the cuneiform and unciform.
The articular surfaces are covered by a thin layer of cartilage, and connected by
the following ligaments : —
Anterior or Palmar. External Lateral.
Posterior or Dorsal. Internal Lateral.
The Anterior or Palmar LAgaments consist of short fibres, which pass obliquely
between the bones of the first and second row on the palmar surface.
The Posterior or Dorsal Ligaments have a similar arrangement on the dorsal
surface of the carpus.
The Lateral Ligaments are 'vq.tj short; they are placed, one on the radial, the
other on the ulnar side of the carpus ; the former, the stronger and more distinct,
connecting the scaphoid and trapezium bones, the latter the cuneiform and unci-
form; they are continuous with the lateral ligaments of the wrist -joint.
The common Synovial Memhrane of the Carpus is very extensive; it lines the
under surface of the scaphoid, semilunar, and cuneiform bones, sending upwards
two prolongations between their contiguous surfaces; it is then reflected over
the bones of the second row, and sends down three prolongations between them,
which line their contiguous surfaces, and invest the carpal extremities of the
four inner metacarpal bones. There is a separate synovial membrane between
the pisiform and cuneiform bones.
318 ARTICULATIONS.
Actions. Tlie articulation of tlie hand and wrist, considered as a wliole, is
divided by Meyer^ into three parts: — 1. Tlie radius and the triangular cartilage.
2. The hand proper, viz., the matacarpal bones with the four carpal bones on
which they are supported, the Linciform, os magnum, trapezoid, and trapezium ;
and 3. The meniscus^ formed by the cuneiform, semilunar, and scaphoid; the
pisiform bone having no essential part in the movements of the hand.
These three elements form two joints:- — 1. The anterior between the hand
and meniscus (transverse carpal joint, as it may be called), mainly ginglymoid
in character; 2. The posterior (wrist-joint proper) between the meniscus and
bones of the forearm, chiefly arthrodial.
1. The joint between the meniscus and the other four bones of the carpus is
subdivided into three portions — the central formed between the deep cup of the
semilunar above and the head of the os magnum with the adjacent part of the
unciform below, is a ginglymoid joint in which some rotation is allowed; the
radial portion formed by the scaphoid articulating with a portion of the os
magnum, the trapezoid, and trapezium, represents also a ginglymoid joint in
which rotation is permitted ; while the u.lnar portion or articulation of the cunei-
form with the unciform partakes more of the arthrodial character. The axes of
iTLOvement of these joints are inclined to each other at a considerable angle, so
that in flexion of the hand on the forearm the carpal bones are brought together,
and on the contrary are separated in extension.
Extension of the hand on the forearm or dorsi-flexion Meyer divides into three
movements, corresponding to the three portions of the transverse joint. In the
first the semilunar moves in its hinge-joint around the head of the os magnum
and the edge of the unciform until its motion is checked by its bony surface
coming into contact with the adjoining portions of those bones. The second
part of the movement consists of a hinge-like motion of the scaphoid round the-
OS magnum continued by a rotation of the same bone on a pivot formed by the
head of the os magnum until it is checked by the tension of the ligaments uniting
it to the trapezium and trapezoid. The third part is effected by the cuneiform
which glides outwards or towards the radial side on the unciform to a certain
extent and carries the semilunar with it, so that it is disengaged from its contact
with the OS magnum and unciform, and undergoes a further separation from
those bones towards the radial side.
Flexion of the hand on the forearm, or palmar flexion, is accomplished by the
semilunar (with the cuneiform) hinging around the os magnum and unciform,
and the scaphoid moving in the same sense until the movement is checked by
these two bones coming together.
It follows from this that the movement of extension in this joint is consider-
able, while that of flexion is but slight.^ A very trifling rotation is permitted
around the head of the os magnum as a pivot ; but only to the extent which is
determined by the tension of the ligaments connected with that bone.
2. The articulation between the forearm and carpus is formed chiefly by tlic
radius articulating with the scaphoid and semilunar, the articulation between the
triangular cartilage and cuneiform being of subordinate importance. The ridge
vv^hich divides the two concave surfaces on the end of the radius is the centre of
motion in the chief part of the joint. This ridge is so inclined as to represent a
portion of a spiral line passing from the point of the styloid process of the ulna
to the ridge on the scaphoid which fits in between the trapezium and trapezoid.
The result of this arrangement is that in flexion and extension of the hand, its
radial bordc^r describes more of a curve than its ulnar, Avliich moves more ])arallcl
to the axis of the forearm. The ulnar border of the hand is also brought moro
' llci''licrt 11. T)u IJois Ptcyniotid, Arrlu'r, IHGC).
'^ It may not he iimiss 1o nofo lliat Prof, rrumpliry atd'ibntos a very considorablo sliare in tlio
flexion of llic liaiid 1o tliis Iransvcr.se carpal joint, and l)clieves that extension in the wrisl-joint
is more free than flexion. The Human Skclduv, p. 430.
CARPO-METACARPAL. 310
towards tlie middle line of the forearm than its radial — the meniscus (carrjdng
the hand with it) is displaced towards the radial side in extension and towards
the ulnar in flexion. As above noted, extension takes place to a considerable
extent in the transverse carpal joint as well as in the wrist-joint, while flexion
takes place chiefly in the latter.
With regard to abduction and adduction of the hand (or "radial" and "ulnar"
flexion), these also are elTected chiefly in the latter joint, or indeed entirely, if
considered accurately, i.e.^ if the terms are limited, as in strictness they should
be, to movements in the plane which passes through the axis of the forearm and
the straight line joining the styloid processes of the radius and ulna when these
bones are at rest on each other. In abduction or radial flexion, the tubercle
of the scaphoid glides towards the styloid process of the radius, carrying the
meniscus towards the ulnar side, till its movement is stopped by the tension of
the internal lateral ligament of the wrist, and by atmospheric pressure. The
same traction which pulls the hand to the radial side, exerts, however, an influ-
ence on the transverse carpal joint which produces a movement of extension or
dorsi-flexion, and as the meniscus follows this movement to a slight extent, the
tubercle of the scaphoid is disengaged to some degree from its contact with the
styloid process of the radius, and the abduction can be then carried a little further.
From this it follows that any considerable abduction of the hand must also be
combined with extension. The force which produces abduction Meyer regards
as being usually the resultant of the action of the combined tendons of the
Flexor carpi radialis and the two Extensores carpi radiales, passing through the
posterior part of the axis of the scaphoid bone.
Adduction, or ulnar flexion, of the hand is less opposed than abduction. In
this movement, the semilunar is drawn across the ridge on the radius, drawing
with it the cuneiform along the face of the triangular fibro-cartilage. This
movement does not tend to separate the scaphoid very much from the radius,
since the curved surface formed by the end of the radius and its styloid process,
is much the same in shape as the opposed surface of the scaphoid ; consequentl}^
the movement of adduction is much more extensive and. uncomplicated than that
of abduction. It is easily combined with flexion or extension, by preponderating
actions of the Flexor or Extensor carpi ulnaris respectively, but extension is
much more easily permitted than flexion.
IX. Carpo-metacaepal Arttcflatton'S.
1. Articulation of the Metacarpal Boxe of the Thumb with the
Trapezium.
This is an arthrodial joint, which enjoys great freedom of movement, on
account of the configuration of its articular surfaces, which are saddle-shaped,
so that, on section, each bone appears to be received into a cavity in the other,
according to the direction in which they are cut. Hence this joint is sometimes
described as one " by reciprocal reception." Its ligaments are a capsular and
synovial membrane.
The capsular ligament is a thick but loose capsule, which passes from the
circumference of the upper extremity of the metacarpal bone to the rough edge
bounding the articular surface of the trapezium ; it is thickest externally and
behind, and lined by a separate synovial membrane.
2. Articulations of the Metacarpal Bones of the Fingers with the
Carpus.
The joints formed between the carpus and four inner metacarpal bones are
connected together by dorsal, palmar, and interosseous ligaments.
The Dorsal Ligaments^ the strongest and most distinct, connect the carpal
320
ARTICULATIONS.
and metacarpal bones on tlieir dorsal surface. THe second metacarpal bone
receives two fasciculi, one from the trapezium, the other from the trapezoid;
the third metacarj^al receives one from the os magnum ; the fourth two, one from
the OS magnum, and one from the unciform ; the fifth receives a single fasciculus
from the unciform bone.
The Palmar Ligaments have a somewhat similar arrangement on the palmar
surface, with the exception of the third metacarpal, which has three ligaments,
an external one from the trapezium, situated above the sheath of the tendon of
the Flexor carpi radialis ; a middle one, from the os magnum ; and an internal
one from the unciform.
The Interosseous Ligaments consist of short thick fibres, which are limited to
one part of the carpo-metacarpal articulation ; they connect the contiguous infe-
rior angles of the os magnum and unciform with the adjacent surfaces of the
third and fourth metacarpal bones.
The Synovial Membrane is a continuation of that between the two rows of
carpal bones. Occasionally, the articulation of the unciform with the fourth
and fifth metacarpal bones has a separate synovial membrane.
The synovial membranes of the wrist (Fig. 229) are thus seen to be five in
number. The first^ the membrana sacciformis, lines the lower end of the ulna,
the sigmoid cavity of the radius, and the upper surface of the triangular inter-
articular fibro-cartilage. The second lines the lower end of the radius and inter-
Fig. 229. — Vertical Section through the Articulations at the Wrist, showing the five
Synovial Membranes.
articular fibro-cartilage above, and the scaphoid, semilunar, and cuneiform
])(jiios below. The tli/i.rd^ the most extensive, covers the contiguous surfaces of
the two rows of carpal bones, and passing between the bones of the second row,
lines the carpal extremities of the four inner metacarpal bones. The fourth lines
the adjacent surfaces of tlie trapezium and metacarjial bone of the thumb. The
ffth, lines the adjacent snrfaccjs of the cuneiform and ])isif()rm bones.
Actions. Tlic inovcincnt permitted in tlic carpo-metacarpal articulations is.
limited to a slight gliding of the ar-ticul;ir surfaces ii])on each other, the extent of
which varies in the dificrciit joints. Thus the articulation of the metacarpal
METACARPO-PHALANGEAL.
321
bone of tlie tliumb witli tlie trapezium is most movable, tlien tbe fiftli meta-
carpal, and then the fourth. The second and third are almost immovable. In
the articulation of the metacarpal bone of the thumb with the trapezium, the
movements permitted are flexion, extension, adduction, abduction, and circum-
duction.
LATERAL LICAMC
Meta^arpo - pJiula.nge/d
A.rti.c''}
3. Aeticulations of the Metacaepal Bones with each othee.
The carpal extremities of the metacarpal bones articulate with one another at
each side by small surfaces covered with cartilage, and connected together by
dorsal, palmar, and interosseous ligaments.
The Dorsal and Palmar Ligaments pass transversely from one bone to another
on the dorsal and palmar surfaces. The Interosseous Ligaments pass between
their contiguous surfaces, just beneath their lateral articular facets.
The Synovial Memhrane lining the lateral facets is a reflection from that
between the two rows of carpal bones.
The digital extremities of the metacarpal bones are connected together by a
narrow fibrous band, the trans-
verse ligament (Fig. 230) which Fij?. 230.— Articulations of the Phalanges,
passes transversely across their
anterior surfaces, and is blend-
ed with the ligaments of the
metacarpo-phalangeal articu-
lations. Its anterior surface
presents four grooves for the
passage of the flexor tendons.
Its posterior surface blends
with the ligaments of the meta-
carpo-phalangeal articulations.
X. Metacaepo-phalangeal
Aeticulations. (Fig. 230.)
These articulations are of
the ginglymus kind, formed
by the reception of the rounded
head of the metacarpal bone
into a superficial cavity in the
extremity of the first phalanx.
They are connected by the
following ligaments : —
Anterior. Two Lateral.
The Anterior Ligaments ti^ iJ'£-H ArUci'f
[Glenoid Ligaments of Cru-
veilhier) are thick, dense, and
fibro-cartilaginous in texture.
Each is placed on the palmar
surface of the joint, in the
interval between the lateral
ligaments, to which they are
connected; they are loosely
united to the metacarpal bone,
but very firmly to the base of
the first phalanges. Their palmar surface is intimately blended with the trans-
verse ligament, forming a groove for the passage of the flexor tendons, the
sheath surrounding which is connected to each side of the groove. By their
21
822 ARTICUUATIONS.
deep surface, tliey form part of the articular surface for the head of the meta-
carpal bone, and are lined bj a synovial membrane.
The Lateral L'ujaments are strong rounded cords, placed one on each side of
the joint, each being attached by one extremity to the tubercle on the side of
the head of the metacarpal bone, and by the other to the contiguous extremity
of the phalanx.
The j)osterior ligament is supplied by the extensor tendon placed over the back
of each joint.
Actions. The movements which occur in these joints are flexion, extension,
adduction, abduction, and circumduction ; the lateral movements are very limited.
XI. Aeticulations of the Phalanges.
These are ginglymus joints, connected by the following ligaments: —
Anterior. Two Lateral.
The arrangement of these ligaments is similar to those in the metacarpo-
phalangeal articulations; the extensor tendon supplies the place of a posterior
ligament.
Actions. The only movements permitted in the phalangeal joints are flexion
and extension; these movements are more extensive between the first and second
phalanges than between the second and third. The movement of flexion is very
considerable, but the extension is limited by the anterior and lateral ligaments.
AETICULATIONS OF THE LOWER EXTEEMITY.
The articulations of the Lower Extremity comprise the following groups : —
I. The hip-joint. II. The knee-joint. III. The articulations between the tibia
and fibula. lY. The ankle-joint. V. The articulations of the tarsus. VI. The
tarso-metatarsal articulations. VII. The metatarso-phalangeal articulations.
VIII. The articulations of the phalanges.
I. Hip-joint. (Fig. 231.)
This articulation is an enarthrodial, or ball-and-socket joint, formed by the
reception of the head of the femur into the cup-shaped cavity of the acetabulum.
The articulating surfaces are covered with cartilage, that on the head of the
femur being thicker at the centre than at the circumference, and covering the
entire surface with the exception of a depression just below its centre at the
ligamentum teres; that covering the acetabulum is much thinner at the centre
than at the circumference, being deficient in the situation of the circular depres-
sion at the bottom of the cavity. The ligaments of the joint are the
Capsular. Teres.
Ilio-fcmoral. Cotyloid.
Transverse.
Tlic Cn'ps'iiJar Tjifjam.ont is a strong, dense, ligamentous capsule, embracing
the margin of the acetabulum above, and surrounding tlic neck of the femur
below. Its itpper circuwference is attached to the acetabulum two or three lines
external to the cotyloid ligamciil ; but opposite the notch where the margin of
this cavity is deficient, it is coiineulcd with the transverse ligament, and by a
few fibres to the edge of the obturator foramen. Its lower circumference sur-
rounds the neck of tl)c femur, being attached, in front, to the spiral or anterior
intcrtrochanto.ric line; above, to the base of the neck ; behind, to the middle of
the neck of tlie bone, about lialf an inch above the posterior intertrochanteric
line. It is much thicker at the upper and fore part of the joint where the
HIP-JOINT.
323
greatest amount of resistance is required, than below, wliere it is tliin, loose,
and longer than in any other part. Its external surface (Fig. 220, p. 300) is
rough, covered by numerous muscles, and separated in front from the Psoas
and Iliacus by a synovial bursa, which not unfrequently communicates by a
Fig. 231. — Left Hip-joiat laid open.
circular aperture with the cavity of the joint. It differs from the capsular
ligament of the shoulder, in being much less loose and lax, and in not being
perforated for the passage of a tendon.
The Ilio-femoral Ligament (Fig. 220) is an accessory band of fibres, extending
obliquely across the front of the joint; it is intimately connected with the
capsular ligament, and serves to strengthen it in this situation. It is attached,
above, to the anterior inferior spine of the ilium ; below, to the anterior inter-
trochanteric line. Its lower part is sometimes bifurcated, an arrangement which
Bigelow seems to regard as the usual one, so that he describes it under the name
of "the Y-ligament."'
The Ligamentum Teres is a triangular band of fibres, implanted, by its apex,
into the depression a little behind and below the centre of the head of the
femur, and by its broad base, which consists of two bundles of fibres, into the
margins of the notch at the bottom of the acetabulum, becoming blended with
the transverse ligament. It is formed of a bundle of fibres, the thickness and
strength of which are very variable, surrounded by a tubular sheath of svnovial
membrane. Sometimes, only the synovial fold exists, or the ligament mav be
altogether absent. The use of the round ligament is to check rotation outwards,
as well as adduction in the flexed position (Figs. 232, 233) : it thus assists in
preventmg dislocation of the head of the femur forwards and outwards, an
' Bigelow on the Hip-joint.
324
ARTICULATIONS.
accident likely to occur from the necessary mechanism of the joint, if not pro-
vided against by this ligament and the thick anterior joart of the capsule.^
Fig. 232. — The Hip-Joint laid open from the Pelvis, to show the Ligamentum Teres put on the
stretch by rotation of the Femur outwards.
The Cotyloid Ligament is a fibro-cartilaginous rim attached to the margin of
the acetabulum, the cavity of which it deepens : at the same time it protects the
edges of the bone, and tills up the inequalities on its surface. It is prismoid in
form, its base being attached to the margin of the acetabulum, and its opposite
Fig. 233. — The same view of the Hip as in the former figure, to show the Ligamentum Teres
put on the stretch by adduction in the flexed position.
edge being free and sharp ; whilst its two surfaces are invested by synovial
membrane, the external one being in contact with the capsular ligament, the
internal one being inclined inwards so as to narrow the acetabulum and embrace
the cartilaginous surface of the head of the femur. It is much thicker above
and behind than below and in front, and consists of close compact fibres which
' Ron an inifrosiiiig paper "On the Use nf the Round Tjigamont of Hie TTip-Toint." by Dr.
J. StnithfTS. Edinhimih Modiml Journal. 1858. This ligament is best studied with the assist-
ance of apreparadon in wlii(;h Ihe floor of the aeeiabniiim has been removed wilh a trephine,
and Iho ligament exposr-d by cleaning away the fat. Mr. Savory, without denying the other
nses attribntfd tf> lliis ligament, says that it is always made tense in the upright position, and is
still further tightened in stjindingon one ]e<r ; and llierefon^ he maintains that its main function
is to support the weiLfht of the body, and distribute its pressure equally over the whole surface of
the actaliulum and heiul nf the femur. Latirct, I\Iay 23, 1874.
KNEE-JOINT. ' 325
arise from different points of tlie circumference of tlie acetabulum, and inter-
lace with each, other at very acute angles.
The Transverse Ligament is a strong flattened band of fibres, which crosses
the notch at the lower part of the acetabulum, and converts it into a foramen.
It is continuous at each side with the cotyloid ligament. An interval is left
beneath the ligament for the passage of nutrient vessels to the joint.
The Synovial Memhrane is very extensive. Commencing at the margin of the
cartilaginous surface of the head of the femur, it covers all that portion of the
neck which is contained within the joint ; from the head it is reflected on the
internal surface of the capsular ligament, covers both surfaces of the cotyloid
ligament, and the mass of fat contained in the fossa at the bottom of the aceta-
bulum, and is prolonged in the form of a tabular sheath around the ligamentum
teres, as far as the head of the femur.
The muscles in relation with the joint are, in front, the Psoas and Iliacus,
separated from the capsular ligament by a synovial bursa ; above, the straight
head of the Eectus and Gluteus minimus, 'the latter being closely adherent to
the capsule : internally, the Obturator externus and Pectineus : behind the
Pyriformis Gemellus superior, Obturator internus, Gemellus inferior, Obturator
externus, and Quadratus fern oris.
The arteries supplying the joint are derived from the obturator, sciatic,
internal circumflex, and gluteal.
The Nerves are articular branches from the sacral plexus, great sciatic, obtu-
rator, and accessory obturator nerves.
Actions. The movements of the hip, like all enarthrodial joints, are very
extensive ; they are, flexion, extension, adduction, abduction, circumduction,
and rotation.
The hip-joint presents a very striking contrast to the other great enarthrodial
joint — the shoulder — in the much more complete mechanical arrangements for
its security and for the limitation of its motions. In the shoulder, as we have
seen, the head of the humerus is not adapted at all in shape to the glenoid cavity,
and is hardly restrained in any of its ordinary movements by the capsular liga-
ment. In the hip-joint, on the contrary, the head of the femur is closely fitted
to the acetabulum for a distance extending over nearly half a sphere, and at the
margin of the bony cup it is still more closely embraced by the ligamentous ring
of the cotyloid ligament, so that the head of the femur is held in its place by that
ligament even when the fibres of the capsule have been quite divided (Humphry).
The anterior portion of the capsule described as the ilio-femoral or accessory
ligament, is the strongest of all the ligaments in the body, and is put on the
stretch by any attempt to extend the femur beyond a straight line with the trunk.
That is to say, this ligament is the chief agent in maintaining the erect position
without muscular fatigue, the action of the extensor muscles of the buttock being
balanced by the tension of the ilio-femoral and capsular ligaments. The security
of the joint is also provided for by the two bones being directly united through
the ligamentum teres. Flexion of the hip-joint is arrested by the soft parts of
the thigh and abdomen being brought into contact ;' extension by the tension of
the ilio-femoral ligament and front of the capsule ; adduction by the upper part
of the accessory ligament and of the capsule, and in the flexed position of the
limb by the ligamentum teres ; abduction by the lower portion of the ilio-femoral
ligament and of the capsule ; rotation outwards by the front part of the capsule,
and the ligamentum teres, and rotation inwards by the back part of the capsule.
II. Knee-joint.
The Knee is a ginglymus, or hinge joint; the bones entering into its formation
are, the condyles of the femur above, the head of the tibia below, and the patella
' The hip-joint cannot be completely flexed, in most persons, without at the same time flexingf
the knee; on account of the shortness of the ham-string muscles. Cleland, Journ. of Anat. and
Phys. No. I. Old Series, p. 87.
326
ARTICULATIONS.
in front. The articular surfaces are covered with cartilage, and connected
together bj ligaments, some of which are placed on the exterior of the joint,
whilst others occupy its interior.
Exterior Ligaments.
Anterior, or Ligamentum Pa-
tellee.
Posterior, or Ligamentum Pos-
ticum AViuslowii.
Internal Lateral.
Two External Lateral.
Capsular.
Interior Ligaments.
Anterior, or External Crucial.
Posterior, or Internal Crucial.
Two Semilunar Fibro- cartilages.
Transverse.
Coronary,
Ligamentum mucosum.
Ligamenta alaria.
The Anterior Ligament.^ or Ligamentum Patellse (Fig. 234), is that portion of
the common tendon of the extensor muscles of the thigh which is continued from
the patella to the tubercle of the tibia, supplying the place of an anterior liga-
ment. It is a strong, flat, ligamentous band, about three inches in length,
attached, above, to the apex of the patella and the rough depression on its poste-
rior surface ; below to the lower part of the tuberosity of the tibia ; its superficial
fibres being continuous across the front of the patella with those of the tendon
of the Quadriceps extensor. Two synovial bursas are connected with this liga-
ment and the patella ; one is interposed between the patella and the skin covering
its anterior surface ; the other, of small size, between the ligamentum patellse
Fig. 234. — Eight Knee-joint. Anterior View.
Fig. 235. — Right Knee-joint. Posterior View.
rr'
and the upper part of llic tuberosity of the tibia. The posterior surfixcc of this
hgarnent is separatcHl aljovc from tlic knee-joint by a large mass of adipose
tissue; its lateral margins i\n\ continuous willi tlie aponeuroses derived from the
Vasti muscles.
KNEE-JOINT. 327
The Posterior Ligaraent^ Lig amentum Posticum Winslowii (Fig. 235), is a broad,
flat, fibrous band, wliicli covers over tlie whole of the back part of the joint. It
consists of a central and two lateral portions, the latter formed chiefly of vertical
fibres, which arise above from the condyles of the femur, and are connected
below with the back part of the head of the tibia, being closely united with the
tendons of the Grastrocnemiiis, Plantaris, and Popliteus muscles ; the central
portion is formed of fasciculi, obliquely directed and separated from one another
by apertures for the passage of vessels. The strongest of these fasciculi is derived
from the tendon of the Semi-membranosus, and passes from the back part of the
inner tuberosity of the tibia, obliquely upwards and outwards to the back part
of the outer condyle of the femur. The posterior ligament forms part of the
floor of the popliteal space, and the popliteal artery rests upon it.
The Internal Lateral Ligament is a broad, flat, membranous band, thicker
behind than in front, and situated nearer to the back than the front of the joint.
It is attached, above, to the inner tuberosity of the femur ; below, to the inner
tuberosity and inner surface of the shaft of the tibia, to the extent of about two
inches. It is crossed, at its lower part, by the aponeurosis of the Sartorius, and
the tendons of the Grracilis and Semitendinosus muscles, a synovial bursa being
interposed. Its deep surface covers the anterior portion of the tendon of the
Semi-membranosus, the synovial membrane of the joint, and the inferior internal
articular artery and nerve ; it is intimately adherent to the internal semilunar
fibrocartilao;e.
The Long External Lateral Ligament is a strong, rounded, fibrous cord, situated
nearer to the back than the front of the joint. It is attached, above, to the outer
tuberosity of the femur ; below, to the outer part of the head of the fibula. Its
outer surface is covered by the tendon of the Biceps, which divides at its insertion
into two parts, separated by the ligament. The ligament has, passing beneath
it, the tendon of the Popliteus muscle, and the inferior external articular vessels
and nerve.
The Short External fjateral Ligament is an accessory bundle of fibres, placed
behind and parallel with the preceding; attached, above, to the lower part of
the outer tuberosity of the femur ; below, to the summit of the styloid process
of the fibula. This ligament is intimately connected with the capsular ligament,
and has, passing beneath it, the tendon of the Popliteus muscle.
The Capsular Ligament consists of an exceedingly thin, but strong, fibrous
membrane, which fills in the intervals left by the preceding ligaments. It is
attached to the femur immediately above its articular surface; below, to the
upper border and sides of the patella and the margins of the head of the tibia
and interarticular cartilages, and is continuous behind with the posterior liga-
ment. This membrane is strengthened by fibrous expansions, derived from the
fascia lata, from the Yasti and Crureus muscles, and from the Biceps, Sartorius,
and tendon of the Semimembranosus.
The Crucial are two interosseous ligaments of considerable strength, situated
in the interior of the joint, nearer its posterior than its anterior part. They
are called crucial^ because they cross each other, somewhat like the lines of the
letter X; and have received the names anterior and posterior^ from the position
of their attachment to the tibia.
The Anterior or External Crucial Ijigam.ent (Fig.. 236), smaller than the pos-
terior, is attached to the inner side of the depression in front of the spine of the
tibia, being blended with the anterior extremity of the external semilunar fibro-
cartilage, and passing obliquely upwards, backwards, and outwards, is inserted
into the inner and back part of the outer condyle of the femur.
The Posterior or Internal Crucial Ligament is larger in size, but less oblique
in its direction than the anterior. It is attached to the back part of the depres-
sion behind the spine of the tibia, to the popliteal notch, and to the posterior
extremity of the external semilunar fibro-cartilage ; and passes upwards, for-
wards, and inwards, to be inserted into the outer and fore-part of the inner
328
ARTICULATIONS.
Fig. 236.— Right Knee-joint.
Internal Lisanieuts.
Showing
condyle of the femur. As it crosses tlie anterior crncial ligament, a fasciculus
is given off from it, whicli blends witli the posterior part of that ligament. It
is in relation, in front, with the anterior
crucial ligament; behind, with the liga-
mentum posticum Winslowii.
The Semilunar Fihro-cartilages (Fig.
237) are two crescentic lamella, which
are attached to the margins of the head
of the tibia, and serve to deepen its
surface for articulation with the con-
dyles of the femur. The circumference
of each cartilage is thick and convex;
the inner free border, thin and concave.
Their upper surfaces are concave, and
in relation with the condyles of the
femur ; their lower surfaces are flat, and
rest upon the head of the tibia. Each
cartilage covers nearly the outer two-
thirds of the corresjDonding articular
surface of the tibia, leaving the inner
third uncovered; both surfaces are
smooth, and invested by synovial mem-
brane.
The Internal Semilunar Fihro-carti-
lage is nearly semicircular in form, a
little elongated from before backwards,
and broader behind than in front; its'
convex border is united to the internal
lateral ligament, and to the head of the
tibia, by means of the coronary liga-
ments; its anterior extremity, thin and
pointed, is firmly implanted into a de-
pression in front of the inner articular
surface of the tibia; its posterior ex-
tremity into the depression behind the' spine, between the attachment of the
external cartilage and posterior crucial ligament.
The External Semilunar Fihro-cartilaye forms nearly an entire circle, covering
a larger portion of the articular surface than the internal one. It is grooved
on its outer side, for the ten-
Fig. 237.— Head of Tibia, with Semilunar Cartilages, etc. don of the Popliteus muscle
Seen from above. Right Side. j^^ circumference is held in
connection with the head of
the tibia, by means of the
coronary ligaments; and its
two extremities are firmly
implanted in the depressions
in front and behind the spine
of the tibia. These extremi-
ties, at their insertion, are
interposed between tlie at-
tachments of the internal car-
tilage. The external semi-
lunar fibro- cartilage gives
ofl" from its anterior harder a
fasciculus, which forms the
tran.sverso ligament. By its anterior extremity, it is continuous with the anterior
(fiicial ligament. 1\h posterior ^x/rem/V?/ divides into three slips; two of these
KNEE-JOINT. 329
pass upwards and forwards, and are inserted into tlie outer side of the inner
tuberosity of the tibia, one in front, the other behind the posterior crucial
ligament; the third fasciculus is inserted into the back part of the anterior
crucial ligament.
The Transverse Ligmnent is a band of fibres, which passes transversely from
the anterior convex margin of the external semilunar cartilage to the anterior
extremity of the internal cartilage ; its thickness varies considerably in different
subjects.
The Coronary Ligaments consist of numerous short fibrous bands, which con-
nect the convex border of the semilunar cartilages with the circumference of
the head of the tibia, and with the other ligaments surrounding the joint.
The Synovial Memhrane of the knee-joint is the largest and most extensive in
the body. Commencing at the upper border of the patella, it forms a large cul-
de-sac beneath the Extensor tendon of the thigh : this is sometimes replaced \)j
a synovial bursa interposed between the tendon and the front of the femur,
which in some subjects communicates with the synovial membrane of the knee-
joint by an orifice of variable size. On each side of the patella, the synovial
membrane extends beneath the aponeurosis of the Vasti muscles, and more
especially beneath that of the Yastus internus; and, below the patella, it is
separated from the anterior ligament by a considerable quantity of adipose
tissue. In this situation it sends off a triangular prolongation, containing a few
ligamentous fibres, which extends from the anterior part of the joint below the
patella, to the front of the intercondyloid notch. This fold has been termed the
ligartientutn mucosum. The ligamenta alaria consist of two fringe-like folds,
which extend from the sides of the ligamentum mucosum, upwards and out-
wards, to the sides of the patella. The synovial membrane invests the semilunar
fibro-cartilages, and on the back part of the external one forms a cul-de-sac
between the groove on its surface, and the tendon of the Popliteus ; it is con-
tinued to the articular surface of the tibia; surrounds the crucial ligaments,
and the inner surface of the ligaments which enclose the joint; lastly, it ap-
proaches the condyles of the femur, and from them is continued on to the lower
part of the front of the shaft. The pouch of synovial membrane between the
Extensor tendon and front of the femur is supported, during the movements of
the knee, by a small muscle, the Subcruraeus, which is inserted into it.-
The Arteries supplying the joint are derived from the anastomotic branch of
the femoral, articular brancliBs of the popliteal, and recurrent branch of the
anterior tibial.
The Nerves are derived from the obturator, anterior crural, and external and
internal popliteal.
Actions. The knee-joint allows of movement of flexion and extension, and of
slight rotation inwards and outwards. The complicated mechanism of this joint
renders it necessary to study each of these movements separately, pointing out
incidentally the functions of each of the principal components of the joint. The
tibia executes a rotatory movement during flexion around an imaginary axis drawn
transversely through its upper end. This causes a change in the apposition of
the tibia and femur. Thus, in extreme extension, it is the anterior portion of the
tibia which is in contact with the femur ; in the semiflexed position, its middle ;
in complete flexion, its posterior edge.^ Also, during flexion the articular sur-
face of the tibia, covered by the interarticular cartilages, glides backwards on
the femur. The patella is attached by the inextensible ligamentum patellse to
the tubercle of the tibia, and as the tibia glides backwards, the patella falls more
and more into the intercondyloid notch of the femur. The ligamentum patellai
is put on the stretch during flexion, as is also the posterior crucial ligament in
extreme flexion. The other ligaments are all relaxed by flexion of the joint,
though the relaxation of the anterior crucial ligament is very trifling. In
' See Plate XLVII. in Humphry, on The Skeleton.
330 ARTICULATIONS.
partial flexion, before the ligamentum patellaj comes upon tlie stretcli, and while
both crucial ligaments are somewhat relaxed, some rotation of the joint is per-
mitted. Flexion is onlj checked during life by the contact of the leg with the
thigh. In extension^ the ligamentum patellae becomes relaxed, and, in extreme
extension, completely so, so as to allow free lateral movement to the patella,
which then rests on the front of the condyles of the femur. The other ligaments
are all on the stretch. When the limb has been brought into a straight line ex-
tension is checked, mainly by the tension of the posterior crucial ligament.
The movements of rotation of which the knee is susceptible are permitted in the
semiflexed condition by the partial relaxation of both crucial ligaments, as well
as the lateral ligaments. Eotation inwards (or pronation of the leg) is checked
by the anterior crucial ligament. The chief agent in effecting this movement
is the Popliteus muscle. Eotation outwards (or supination) is checked by the
posterior crucial ligament. It is effected mainly by the Biceps. The main
fanction of the crucial ligaments is to act as a direct bond of union between
the tibia and femur, preventing the former bone from being carried too far
backwards or forwards. Thej^ also assist the lateral ligaments in resisting any
lateral bending of the joint. The interarticular cartilages are intended, as it
seems, to adapt the surface of the tibia to the shape of the femur to a certain
extent, so as to fill up the intervals which would otherwise be left in the varying
positions of the joint, and to interrupt the jars which would be so frequently
transmitted up the limb in jumping or falls on the feet. The patella is a great
defence to the knee-joint from any injury inflicted in front, and it distributes
upon a large and tolerably even surface during kneeling the pressure which
would otherwise fall upon the prominent ridges of the condyles : it also affords
leverage to the Quadriceps extensor muscle to act upon the tibia, and Mr._
Ward has pointed out^ how this leverage varies in the various positions of the
joint, so that the action of the muscle produces velocity at the expense of force
in the commencement of extension, and on the contrary, at the close of extension
tends to diminish the velocity, and therefore the shock to the ligaments ; whilst
in the standing position it draws the tibia powerfully forwards, and thus main-
tains it in its place.
The folds of synovial membrane and the fatty processes contained in them
act, as it seems, mainly as padding to fill up interspaces and obviate con-
cussions.
The bursa in connection with the synovial membrane will be found described
with the regional anatomy of the popliteal space.
III. Akticulations between the Tibia and Fibula.
The articulations between the tibia and fibula are effected by ligaments which
connect both extremities, as well as the shafts of the bones. They may, con-
sequently, be subdivided into three sets: — 1. The Superior Tibio-fibular articu-
lation. 2. The Middle Tibio-fibular articulation, o. The Inferior Tibio-fibular
articulation.
1. Superior Tibio-fibular Articulation.
This articulation is an arthrodial joint. Tlie contiguous surfaces of the bones
})roscnt two flat oval fiiccts covered with cartilage, and connected together by
the following ligaments: —
Anterior Superior Tibio-fibular.
Postcrio]- Sii)»crior Tibio-iihular.
The Aidrrior Sy/perio'i Ligament (Fig. 236) consists of two or three broad and
' " lliimaii Ostoolog'y," p. 405.
ANKLE-JOINT. 331
jQat bands, wliicli pass obliqiielj upwards and inwards from the head of the
fibula to tlie outer tuberosity of tlie tibia.
The Posterior Superior Ligament is a single thick and broad band, which
passes from the back part of the head of the fibula to the back part of the outer
tuberosity of the tibia. It is covered bj the tendon of the Popliteus muscle.
A Synovial memhrane lines this articulation, which at its upper and back part
is occasionally continuous with that of the knee-joint.
2. Middle Tibio-fibular Articulation.
An interosseous membrane extends between the contiguous margins of the
tibia and fibula, and separates the muscles on the front from those on the back
of the leg. It consists of a thin aponeurotic lamina composed of oblique fibres,
which pass between the interosseous ridges on the two bones. It is broader
above than below, and presents at its upper part a large oval aperture for the
anterior tibial artery forwards to the anterior aspect of the leg ; and at its lower
part an opening for the passage of the anterior peroneal vessels. It is con-
tinuous below with the inferior interosseous ligament; and is perforated in
numerous parts for the passage of small vessels. It is in relation in front with
the Tibialis anticus. Extensor longus digitorum. Extensor proprius poUicis,
Peroneus tertius, and the anterior tibial vessels and nerve ; behind, with the
Tibialis posticus and Flexor longus pollicis.
3. Inferior Tibio-fibular Articulation.
This articulation is formed by the rough convex surface of the inner side of
the lower end of the fibula, connected with a similar rough surface on the outer
side of the tibia. BeloAv, to the extent of about two lines, these surfaces are
smooth and covered with cartilage, which is continuous with that of the ankle-
joint. The ligaments of this joint are —
Inferior Interosseous. Posterior Inferior Tibio-fibular.
Anterior Inferior Tibio-fibular. Transverse.
The Inferior Interosseous Liga^ment consists of numerous short, strong fibrous
bands, which pass between the contiguous rough surfaces of the tibia and fibula,
and constitute the chief bond of union between the bones. This ligament is
continuous, above, with the interosseous membrane.
The Anterior Inferior Ligament (Fig. 239) is a flat, triangular band of fibres,
broader below than above, which extends obliquely downwards and outwards
between the adjacent margins of the tibia and fibula on the front aspect of the
articulation. It is in relation, in front, with the Peroneus tertius, the aponeu-
rosis of the leg, and the integument ; behind, with the inferior interosseous liga-
ment ; and lies in contact with the cartilage covering the astragalus.
The Posterior Inferior Ligament^ smaller than the preceding, is disposed in a
similar manner on the posterior surface of the articulation.
The Transverse Ligament is a long narrow band, continuous with the preced-
ing, passing transversely across the back of the joint, from the external malleolus
to the tibia, a short distance from its malleolar process. This ligament projects
below the margin of the bones, and forms part of the articulating surface for the
aiStragalus.
The Synovial Metnhrane lining the articular surface is derived from that of
the ankle-joint.
Actions. The movement permitted in these articulations is limited to a very
slight gliding of the articular surfaces one upon another,
lY. Ankle-joint.
The Ankle is a ginglymus or hinge joint. The bones entering into its forma-
tion are the lower extremity of the tibia and its malleolus, and the external
332
ARTICULATIONS.
malleolus of tlie fibula. These bones are united above, and forms an arch, to
receive the upper convex surface of the astragalus and its two lateral facets.
The bony surfaces are covered with cartilage, and connected together by the
folloAving ligaments :
Anterior. Internal Lateral.
External Lateral.
The Anterior or Tihio-tarsal Ligament (Fig. 238) is a broad, thin, membranous
layer, attached, above, to the margin of the articular surface of the tibia; below,
Fig. 238. — Aukle-joint: Tarsal and Tarso-metatarsal Articulation. Internal View. Eight Side.
TARSO-METATARGftU
nRTlc ?!
TARSAL ARTICr'
to the margin of the astragalus, in front of its articular surface. It is in relation,
in front, with the Extensor tendons of the toes, with the tendons of the Tibialis
anticus and Peroneus tertius, and the anterior tibial vessels and nerve; behind,
it lies in contact with the synovial membrane.
The Internal Lateral or Deltoid Ligament consists of two layers, superficial
and deep. The superficial layer is a strong, flat, triangular band, attached,
above, to the apex and anterior and posterior borders of the inner malleolus.
The most anterior fibres pass forwards to be inserted into the scaphoid; the
middle descend almost perpendicularly to be inserted into the os calcis; and the
posterior fibres pass backwards and outwards to be attached to the inner side of
the astragalus. The deeper layer consists of a short, thick, and strong fasciculus,
which passes from the apex of the malleolus to the inner surface of the astragalus,
V)clow the articular surface. This ligament is covoi'cd by the tendons of the
^Pibialis jioaticns and Flexor longus digitorum muscles.
'^Phc External Lateral Ligament (Fig. 230) cfuisists of three fasciculi, taking
different directions, and separated by dislinct intervals; for which reason it is
described by .some anatomists as three distinct ligaments.' This would seem the
preferable description, were it not that the old nomenclature has passed into
general use.
The anterior fasciculus^ the shortest oC the thi'ce, ])asses from the anterior
' HuMPiiitY, on The Skeleton, p. .059.
ANKLE-JOINT.
33a
margin of the summit of tlie external malleolus, downwards and forwards, to the
astrao-alus, in front of its external articular facet.
Fig. 239. — Ankle-joiut : Tarsal aud Tarso-metatarsal Articulations. External View. Rio-ht Side
INFERIOR TIBIO-FIBUL«a
ARTIC!?
AMKLE-JOIIMT
TARSAL ARTIC"
TARSO-METATARSAL AHTIC4S
The posterior fasciculus, the most deeply seated, passes from the depression at
the inner and back part of the external malleolus to the astragalus, behind its
external malleolar facet. Its fibres are almost horizontal in direction.
The middle fasciculus, the longest of the three, is a narrow rounded cord,
passing from the apex of the external malleolus downwards and slightly back-
wards to the middle of the outer side of the os calcis. It is covered by the
tendons of the Peroneus longus and brevis.
There is no posterior ligament, its place being supplied by the transverse
ligament of the inferior tibio-fibular articulation.
The Synovial Memhrane invests the inner surface of the ligaments, and sends
a duplicature upwards between the lower extremities of the tibia and fibula for
a short distance.
Relations. The tendons, vessels, and nerves in connection with the joint are,
in front, from within outwards, the Tibialis anticus. Extensor proprius poUicis,
anterior tibial vessels, anterior tibial nerve, Extensor communis digitorum, and
Peroneus tertius ; behind, from within outwards, Tibialis posticus, Flexor longus
digitorum, posterior tibial vessels, posterior tibial nerve. Flexor longus pollicis ;
and, in the groove behind the external malleolus, the tendons of the Peroneus
longus and brevis.
The Arteries supplying the joint are derived from the malleolar branches of
the anterior tibial and peroneal.
The Nerves are derived from the anterior tibial.
Actions. The movements of the joint are limited to flexion and extension.
There is no lateral motion ; the astragalus being embraced by the two malleoli,
and held securely in its place in all positions of the foot. Of these the external
malleolus is longer than the internal, and is situated further backwards, an
arrangement which Prof. Humphry connects with the direction in which the
weight of the body appears to be transmitted to each side of the foot when planted
334 ARTICULATIONS.
on and raised off tlie ground.^ The lower tibio-fibular joint and the elasticity of
the fibula permit of some separation of the two bones in flexion and extension
of the limb, corresponding to the varying size of the surface of the astragalus ;
the latter is considerably wider in front than behind (Fig. 206, p. 268) in order to
resist the tendency to dislocation of the foot backwards in alighting on the toes.
Of the ligaments, the internal, or deltoid, is of very great power — so much so
that it usually resists a force which fractures the process of bone to which it is
attached. Its middle portion, together with the middle fasciculus of the external
lateral ligament, binds the bones of the leg firmly to the foot and resists dis-
placement in every direction. Its anterior and posterior fibres limit exten-
sion and flexion of the foot respectively, and the anterior fibres also limit abduc-
tion. The posterior portion of the external lateral ligament assists the middle
portion in resisting the . displacement of the foot backwards, and deepens the
cavity for the reception of the astragalus. The anterior fasciculus is a security
against the displacement of the foot forwards, and limits extension of the joint.
The movements of abduction and adduction of the foot, together with the minute
changes in form by which it is applied to the ground or takes hold of an object
in climbing, etc., are effected in the tarsal joints; the one which enjoys the
greatest amount of motion being that between the astragalus and os calcis behind,
and the scaphoid and cuboid in front. This is often called the transverse tarsal
joint^ and it, with the subordinate joints of the tarsus, can replace the ankle-joint
in a great measure when the latter has become ankylosed.
Y. Aeticulations of the Taesus.
These articulations may be subdivided into three sets : — 1. The articulations
of the first row of tarsal bones. 2. The articulations of the second row of tarsal
bones. 3. The articulations of the two rows with each other.
1. Articulations of the First Eow of Tarsal Bones,
The articulations between the astragalus and os calcis are two in number —
anterior and posterior. They are arthrodial joints. The bones are connected
together by three ligaments : — ■
External Calcaneo-astragaloid. Posterior Calcaneo-astragaloid.
Interosseous.
The External Calcaneo-astragaloid Ligament (Fig. 239) is a short strong fasci-
culus, passing from the outer edge of the astragalus, immediately beneath its
external malleolar facet, to the outer edge of the os calcis. It is placed in front
of the middle fasciculus of the external lateral ligament of the ankle-joint, with
the fibres of which it is parallel.
The Posterior Calcaneo-astragaloid Ligament (Fig. 238) connects the posterior
extremity of the astragalus Avith tlie upper contiguous surhicc of the os calcis;
it is a short narrow band, the fibres of which are directed obliquely backwards
and inwards.
The interosseous Ligament forms the chief bond of union between the bones.
It consists of numerous vertical and oblique fibres, attached by one extremity to
tlic groove between the articulating surface of the astragalus; by the other, to
a corros])onding d(!])ression on tlie up])cr surface of the os calcis. It is very thick
and strong, being at least an inch in breadth from side to side, and serves to
unite the os calcis and astragalus solidly together.
' Tlie fiict should ho romomhcrcd in operative surgery. Tims llie ankle-joint is more easily
opoiuul nt, flio iiiHidn tlmii tlin outsido, in conKorincncc of \\w. rclativo shortness of the internal
malleolus. Afrain, in outlinfr Ihe flaps for Syine's anii)utation, if the knife is carried as far upwards
and forwards as the point of the iniuT ni<'flcf)lns, the posterior tlap will be unmanageably long,
and great difTiculty will bn found in rcfii.'cling it over the os calcis.
OF THE TARSUS. 335
The Synovial Memlranes (Fig. 241) are two in number : one for tlie posterior
calcaneo-astragaloid articulation ; a second for the anterior calcaneo-astragaloid
joint. The latter synovial membrane is continued forwards between the con-
tiguous surfaces of the astragalus and scaphoid bones.
2. Articulations of the Second Eow of Tarsal Bones.
The articulations between the scaphoid, cuboid, and three cuneiform are
efi'ected by the following ligaments : —
Dorsal. Plantar.
Interosseous.
The Dorsal Ligaments are small bands of parallel fibres, which pass from each
bone to the neighboring bones with which it articulates.
The Plantar Ligaments have the same arrangement on the plantar surface.
The Interosseous Ligaments are four in number. They consist of strong trans-
verse fibres, which pass between the rough non-articular surfaces of adjoining
bones. There is one between the sides of the scaphoid and cuboid ; a second
between the internal and middle cuneiform bones ; a third between the middle
and external cuneiform ; and a fourth between the external cuneiform and cuboid.
The scaphoid and cuboid, when in contact, present each a small articulating
facet, covered with cartilage, and lined either by a separate synovial membrane,
or by an offset from the great tarsal synovial membrane.
3. Articulations of the Two Rows of the Tarsus with each other.
These may be conveniently divided into three sets : The joint between the os
calcis and the cuboid. The ligaments connecting the os calcis with the scaphoid.
The joint between the astragalus and the scaphoid.
The ligaments connecting the os calcis with the cuboid are four in number: —
-p. 1 j Superior Calcaneo-cuboid.
I Internal Calcaneo-cuboid (Interosseous),
pi , j Long Calcaneo-cuboid.
I Short Calcaneo-cuboid.
The Superior Galcaneo-cuhoid Ligament (Fig. 239) is a thin and narrow fasci-
culus, which passes between the contiguous surfaces of the os calcis and cuboid,
on the dorsal surface of the joint.
The Internal Calcaneo-cuboid [Interosseous) Ligament (Fig. 239) is a short, but
thick and strong, band of fibres, arising from the os calcis, in a deep groove which
.intervenes between it and the astragalus ; and closely blended, at its origin, with
the superior calcaneo-scaphoid ligament. It is inserted into the inner side of
the cuboid bone. This ligament forms one of the chief bonds of union between
the first and second row of the tarsus.
The Long Galcaneo-cuhoid (Fig. 2-10), the more superficial of the two plantar
ligaments, is the longest of all the ligaments of the tarsus; it is attached to the
under surface of the os calcis, from near the tuberosities, as far forwards as the
anterior tubercle ; its fibres pass forwards to be attached to the ridge on the under
surface of the cuboid bone, the more superficial fibres being continued onwards
to the bases of the second, third, and fourth metatarsal bones. This ligament
crosses the groove on the under surface of the cuboid bone, converting it into a
' canal for the passage of the tendon of the Peroneus longus.
The Short Galcaneo-cidmd Ligament lies nearer to the bones than the pre-
ceding, from which it is separated by a little areolar adipose tissue. It is
exceedingly broad, about an inch in length, and extends from the tubercle and
the depression in front of it on the fore part of the under surface of the os calcis,
to the inferior surface of the cuboid bone behind the peroneal groove. A sepa-
rate synovial membrane is found in the calcaneo-cuboid articulation.
336
ARTICULATIONS.
Fig. 240. — Ligaments of Plantar Surface
"of the Foot.
The ligaments connecting the os calcis with scaphoid are two in number : —
Superior Calcaneo-scaphoid. Inferior Calcaneo-scaphoid.
The Superior Calcaneo-sco.phoid (Fig. 289) arises, as already mentioned, with
the internal calcaneo-cuboid in the deep groove between the astragalus and os
calcis ; it passes forwards from the inner
side of the anterior extremity of the os
calcis to the outer side of the scaphoid
bone. These two ligaments resemble the
letter Y, being blended together behind,
but separated in front.
The Inferior Calcaneo-scaphoid {¥\g.14ff)
is by far the larger and stronger of the two
ligaments of this articulation ; it is a broad
and thick band of fibres, which passes for-
wards and inwards from the anterior and
inner extremity of the os calcis to the under
surface of the scaphoid bone. This liga-
ment not only serves to connect the os
calcis and scaphoid, but supports the head
of the astragalus, forming part of the
articular cavity in which it is received.
The upper surface is lined by the synovial
membrane continued from the anterior cal-
caneo-astragaloid articulation. Its under
surface is in contact with the tendon of
the Tibialis posticus muscle.^
The articulation between the astragalus
and scaphoid is an arthrodial joint; the
rounded head of the astragalus being re-
ceived into the concavity formed by the
posterior surface of the scaphoid, the ante-
rior articulating surface of the calcaneum,
and the upper surface of the calcaneo-
scaphoid ligament, which fills up the tri-
angular interval between those bones. The
only ligament of this joint is the superior
astragal o- scaphoid, a broad band, which
passes obliquely forwards from the neck
of the astragalus to the superior surface
of the scaphoid bone. It is thin and weak in texture, and covered by the Ex-
tensor tendons. The inferior calcaneo-scaphoid supplies the place of an inferior
ligament.
The Synovial Memhrane which lines the joint is continued forwards from the
anterior calcaneo-astragaloid articulation. This articulation permits of con-
siderable mobility; but its feebleness is such as to allow occasionally of disloca-
tion of the astragalus.
The Synovial Memhranes (Fig. 241) f )nnd in t]ic articulations of the tarsus, are
four in number: owe for tlu; posterior calcaneo-astragaloid articulation; a second
for the anterior calcaneo-astragaloid and astragalo-scaphoid articulations ; a tliird
for the calcanco-cul)oid articulation; and a fouoih for the articulations of the
sca)>lioid with the three cuneiform, the three cuneiform with each other, the
external cuneiform with the cuboid, and the middle and external cuneiform with
the bases of the second and third metatarsal bones. The prolongation which
' Mr. ITiinf:of;k (l(>8cribcH an oxtcnsion of tliis ligainont upwards on tlio inner side of the foot
which coniplelcH the socUct of the joi:it in that direction. Lancet, 18GG, vol. i. p. G18.
TARSO-METATARSAL.
337
lines tTie metatarsal bones passes forwards between tbe external and middle
cuneiform bones. A small synovial membrane is sometimes found between the
contiguous surfaces of the scaphoid and cuboid bones.
Fig. 241.— Oblique Section of the Articulations of the Tarsus and Metatarsus.
Showing the Six Synovial Membranes.
Actions. The movements permitted between the bones of the first row, the
astragalus and os calcis, are limited to a gliding upon each other from before
backwards, and from side to side. The gliding movement which takes place
between the bones of the second row is very slight, the articulation between the
scaphoid and cuneiform bones being more movable than those of the cuneiform
with each other and with the cuboid. The movement which takes place between
the two rows is more extensive, and consists in a sort of rotation, by means of
which the sole of the foot may be slightly flexed, and extended, or carried in-
wards and outwards.
YI. Tarso-metatarsal Articulations.
These are arthrodial joints. The bones entering into their formation are four
tarsal bones, viz., the internal, middle and external cuneiform, and the cuboid,
which articulate with the metatarsal bones of the five toes. The metatarsal bone
of the great toe articulates with the internal cuneiform ; that of the second is
deeply wedged in between the internal and external cuneiform, resting against
the middle cuneiform, and being the most strongly articulated of all the meta-
tarsal bones; the third metatarsal articulates with the extremity of the external
cuneiform ; the fourth with the cuboid and external cuneiform ; and the fifth
with the cuboid. The articular surfaces are covered with cartilage, lined by
synovial membrane, and connected together by the following ligaments : —
Dorsal. Plantar.
Interosseous.
The Dorsal Ligaments consist of strong, fiat, fibrous bands, which connect the
tarsal with the metatarsal bones. The first metatarsal is connected to the inter-
nal cuneiform by a single broad, thin, fibrous band ; the second has three dorsal
lis;aments, one from each cuneiform bone ; the third has one from the external
cuneiform ; and the fourth and fifth have one each from the cuboid.
The Plantar Ligainents consist of longitudinal and oblique fibrous bands con-
necting the tarsal and metatarsal bones, but disposed with less regularity than
on the dorsal surface. Those for the first and second metatarsal are the most
strongly marked ; the second and third metatarsal receive strong fibrous bands,
which pass obliquely across from the internal cuneiform; the plantar ligaments
90
338 ARTICULATIONS.
of tlie fourtli and fifth, metatarsal consist of a few scanty fibres derived from tlie
cuboid.
The Interosseous Ligaments are three in number : internal, middle, and external.
The internal one passes from the outer extremity of the internal cuneiform to
the adjacent angle of the second metatarsal. The middle one, less strong than
the preceding, connects the external cuneiform with the adjacent angle of the
second metatarsal. The external interosseous ligament connects the outer angle
of the external cuneiform with the adjacent side of the third metatarsal.
The Synovial Meonbranes of these articulations are three in number : one for
the metatarsal bone of the great toe, with the internal cuneiform ; one for the
second and third metatarsal bones, with the middle and external cuneiform ;
this is a part of the great tarsal synovial membrane ; and one for the fourth and
fifth metatarsal bones with the cuboid. The synovial membranes of the tarsus
and metatarsus are thus seen to be six in number (Fig. 241).
Aeticulations of the Metatarsal Bones with each other.
The bases of the metatarsal bones, except the first, are connected together by
dorsal, plantar, and interosseous ligaments. The dorsal and jjlantar ligaments
pass from one metatarsal bone to another. The interosseous ligame7its lie deeply
between the rough non-articular portions of their lateral surfaces. The articular
surfaces are covered with cartilage, and provided with synovial membrane, con-
tinued forwards from the tarso-metatarsal joints. The digital extremities of the
metatarsal bones are united by the transverse metatarsal ligament. It connects
the great toe with the rest of the metatarsal bones ; in this respect it differs
from the transverse ligament in the hand.
Actions. The movement permitted in the tarsal ends of the metatarsal bone's
is limited to a slight gliding of the articular surfaces upon one another ; con-
siderable motion, however, takes place in the digital extremities.
VII. Metataeso-phalangeal Articulations.
The heads of the metatarsal bones are connected with the concave articular
surfaces of the first phalanges by the following ligaments : —
Plantar. Two Lateral.
Their arrangement is precisely similar to the corresponding parts in the hand.
The expansion of the Extensor tendon supplies the place of a dorsal ligament.
Actions. The movements permitted in the metatarso-phalaugeal articulations
are flexion, extension, abduction, and adduction.
VIII. Aeticulations of the phalanges.
Tlic ligaments of these articulations are similar to those found in the hand ;
each pair of ])lialangcs being connected by a plantar and two lateral ligaments,
and their articular surfaces lined by synovial membrane. Their actions are also
similar.
For fiirtlior iiirormntion nn lliis siilijeci. tlio Stndont is rofcrrcd to Crnvoilliior's "Anatfmie
DcKcriptivc ;" to Dr. Iliirnplirv's work on " 'I'lie Iliiniiui Skeldon, including the Joiiils;" 1o
Arnold's " 'I'iilinl.T Anntoinicic," Fnscic. 4. Purs 2, Iconos Arlicnlornm ot Tjitrnnienlornni ; and
to llif papers liy Prof. Hermann Meyer (" Peitrilne znr McLhanik des nienscldiclien Knochen-
gcrUstOH") in Ileicliert u. Dii Hois l{eyniond's Archiv.
The Muscles and Fasciae.^
The muscles are connected witK the bones, cartilages, ligaments, and skin,
either directly or through the intervention of fibrous structures, called tendons
or aponeuroses. Where a muscle is attached to bone or cartilage, the fibres
terminate in blunt extremities upon the periosteum or perichondrium, and do
not come into direct relation with the osseous or cartilaginous tissue. Where
muscles are connected with the skin, they either lie as a flattened layer beneath
it, or are connected with its areolar tissue by larger or smaller bundles of fibres,
as in the muscles of the face.
The muscles vary extremely in their form. In the limbs, they are of con-
siderable length, especially the more superficial ones, the deep ones being gene-
rally broad ; they surround the bones, and form an important protection to the
various joints. In the trunk, they are broad, flattened, and expanded, forming
the parieties of the cavities which they inclose ; hence the reason of the terms,
long, hroad^ shorty etc., used in the description of a muscle.
There is a considerable variation in the arrangement of the fibres of certain
muscles with reference to the tendons to which they are attached. In some, the
fibres are arranged longitudinally, and terminate at either end in a narrow
tendon. If the fibres converge, like the plumes of a pen, to one side of a tendon,
which runs the entire length of a muscle, the muscle is said to be penniform^ as
the Peronei ; if they converge to both sides of the tendon, the muscle is called
hipenniform^ as the Eectus femoris ; if they converge from a broad surface to a
narrow tendinous point, the muscle is said to be radiated^ as the Temporal and
Glutei muscles.
They differ no less in size ; the Gastrocnemius forms the chief bulk of the
back of the leg, and the fibres of the Sartorius are nearly two feet in length,
whilst the Stapedius, a small muscle of the internal ear, weighs about a grain,
and its fibres are not more than two lines in length.
The names applied to the various muscles have been derived : 1, from their
situation, as the Tibialis, Radialis, Ulnaris, Peroneus ; 2, from their direction, as
the Rectus abdominis, Obliqui capitis, Transversalis ; 3, from their uses, as
Flexors. Extensors, Abductors, etc. ; 4, from their shape, as the Deltoid, Tra-
pezius, Rhomboideus ; 5, from the number of their divisions, as the Biceps, the
Triceps ; 6, from their points of attachment, as the Sterno-cleido-mastoid,
Sterno-hyoid, Sterno-thyroid.
In the description of a muscle, the term origin is m.eant to imply its more
fixed or central attachment ; and the term insertion the movable point to which
the force of the muscle is directed ; but the origin is absolutely fixed in only a
very small number of muscles, such as those of the face, which are attached by
one extremity to the bone, and by the other to the movable integument ; in the
greater number, the muscle can be made to act from either extremity.
In the dissection of the muscles, the student should pay especial attention to
the exact origin^ insertion^ and actions^ of each, and its more important relations
with surrounding parts. An accurate knowledge of the points of attachment of
• The Muscles and Fascife are described conjointly, in order that the Htndent may consider the
arrangement of the latter in his dissection of the former. It is I'are for the student of anatomy
in this country to have the opportunity of dissecting the fascise separately; and it is for this reason,
as well as from the close connection that exists between the muscles and their investing aponeu-
roses, that they are considered together. Some general observations are first made on the anatomy
of the muscles and fascise, the special description being given in connection with the different
regions.
(339)
340 MUSCLES AND FASCIA.
the muscles is of great importance in the determination of their action. By a
knowledge of the action of the muscles, the surgeon is able to explain the causes
of displacement in various forms of fracture, and the causes which produce dis-
tortion in various deformities, and consequently, to adopt appropriate treatment
in each case. The relations, also, of some of the muscles, especially' those in
immediate apposition with the larger bloodvessels, and the surface-markings
they produce, should be especially remembered, as they form useful guides in
the application of a ligature to those vessels.
Tendons are white, glistening, fibrous cords, varying in length and thickness,
sometimes round, sometimes flattened, of considerable strength, and only slightly
elastic. They consist almost entirely of white fibrous tissue, the fibrils of which
have an undulating course parallel with each other, and are firmly united
together. They are very sparingly supplied with bloodvessels, the smaller ten-
dons presenting in their interior not a trace of them. Nerves also are not
present in the smaller tendons ; but the larger ones, as the tendo Achillis, receive
nerves which accompany the nutrient vessels. The tendons consist principally
of a substance which yields gelatine.
Aponeuroses are fibrous membranes, of a pearly- white color, iridescent, glisten-
ing, and similar in structure to the tendons. They are destitute of nerves, and
the thicker ones only sparingly supplied with bloodvessels.
The tendons and aponeuroses are connected, on the one hand, with the mus-
cles ; and, on the other hand, with the movable structures, as the bones, carti-
lages, ligaments, fibrous membranes (for instance, the sclerotic), and the synovial
membranes (subcrurseus, subanconeus). Where the muscular fibres are in a
direct line with those of the tendon or aponeurosis, the two are directly continu-
ous, the muscular fibre being distinguishable from that of the tendon only by its
striation. But where the muscular fibre joins the tendon or aponeurosis at an
oblique angle, the former terminates, according to Kolliker, in rounded extremi-
ties, which are received into corresponding depressions on the surface of the
latter, the connective tissue between the fibres being continuous with that of the
tendon. The latter mode of attachment occurs in all the penniform and bipen-
niform muscles, and in those muscles the tendons of which commence in a mem-
branous form, as the Gastrocnemius and Soleus.
The Fasciee [fascia^ a bandage) are fibro-areolar or aponeurotic laminae, of
variable thickness and strength, found in all regions of the body, investing the
softer and more delicate organs. The fascias have been subdivided, from the
structure which they present, into two groups, fibro-areolar or superficial fascite,
and aponeurotic or deep fasciae.
The Jihro-areolar fascia is found immediately beneath the integument over
almost the entire surface of the body, and is generally known as the superficial
fascia. It connects the skin with the deep or aponeurolic fascia, and consists
of fibro-areolar tissue, containing in its meshes pellicles of fat in varying quan-
tity. In the eyelids and scrotum, where adipose tissue is rarely deposited, this
tissue is very liable to serous infiltration. The superficial fascia varies in thick-
ness in different parts of the body: in the groin it is so thick as to be capable
of being subdivided into several laminas, but in the palm of the hand it is of
extreme thinness, and intimately adherent to the integument. The superficial
fjiscia is capable of separation into two or more layers, between which are found
the superficial vessels and nerves, and superficial lyiiqihatic glands; as the super-
ficial epigastric vessels in the abdominal region, lhe radial and ulnar veins in
tlic forearm, the s;i))henous veiii^ in lhe leg and Ihigh ; certain cutaneous mus-
cles also are situfitr.d in the sn])('.i-(icial fascia, as the Platysma myoides in the
nock, and the Orbicularis palpebrarum around the eyelids. This fascia is most
distinct at the lower part of the abdomen, llic si-ioi nm, pcrinaMini, and (>\tremi-
ties; is very thin in those regions where musculai- lihfcs arc inserted into the
integument, as on the side of the neck, the fac(\ and aionnd ihe margin of the
anus; and is almost entirely wanting in the palms ol' \\\v. hands and soles of the
OF THE CRANIUM AND FACE. 341
feet, wliere tlie integument is adlierent to the subjacent aponeurosis. Tlie super-
ficial fascia connects tlie skin to the subjacent parts, facilitates the movement of
the skin, serves as a soft nidus for the passage of vessels and nerves to the in-
tegument, and retains the warmth of the body, since the adipose tissue contained
in its areolae is a bad conductor of caloric.
The aponeurotic or deep fascia is a dense inelastic unyielding fibrous membrane,
forming sheaths for the muscles, and affording them broad surfaces for attach-
ment. It consists of shining tendinous fibres, placed parallel with one another,
and connected together by other fibres disposed in a reticular manner. It is
usually exposed on the removal of the superficial fascia, forming a strong in-
vestment, which not only binds down collectively the muscles in each region,
but gives a separate sheath to each, as well as to the vessels and nerves. The
fascias are thick in unprotected situations, as on the outer side of a limb, and
thinner on the inner side. Aponeurotic fasciee are divided into two classes,
aponeuroses of insertion, and aponeuroses of investment.
The aponeuroses of insertion serve for the insertion of muscles. Some of these
are formed by the expansion of a tendon into an aponeurosis, as, for instance, the
tendon of the Sartorius ; others are connected directly to the muscle, as the
aponeuroses of the abdominal muscles.
The aponeuroses of investment form a sheath for the entire limb, as well as for
each individual muscle. Many aponeuroses, however, serve both for invest-
ment and insertion. Thus the aponeurosis given off' from the tendon of the
Biceps of the arm near its insertion is continuous with, and partly forms, the
investing fascia of the forearm, and gives origin to the muscles in this region.
The deep fascias assist the muscles in their action, by the degree of tension and
pressure they make upon their surface : and, in certain situations, this is in-
creased and regulated bj muscular action, as, for instance, by the Tensor vaginae
femoris and Gluteus maximus in the thigh, by the Biceps in the leg, and Pal-
maris longus in the hand. In the limbs, the fasciae not only invest the entire
limb, but give off septa, which separate the various muscles, and are attached
beneath to the periosteum : these prolongations of fasciae are usually spoken of
as intermuscular septa.
The Muscles and Fasciae may be arranged, according to the general division
of the body, into those of the cranium, face, and neck ; those of the trunk;
those of the upper extremity ; and those of the lower extremity.
MUSCLES AND FASCI.E OF THE CRANIUM AND FACE.
The muscles of the Cranium and Face consist of ten groups, arranged accord-
ing to the region in which they are situated.
1. Cranial Region. 6. Superior Maxillar}^ Region.
2. Auricular Region. ' 7. Inferior Maxillary Region.
3. Palpebral Region. 8. Intermaxillary Region.
4. Orbital Region. 9. Temporo-maxillary Region,
5. Nasal Region. . 10. Pterygo-maxillary Region.
The muscles contained in each of these groups are the following : —
1. Cranial Region. 3. Palpebral Region.
Occipito-frontalis. Orbicularis palpebrarum.
Corrugator supercilii.
Levator palpebrae superioris.
Tensor tarsi.
2. Auricular Region.
Attollens aurem. 4. Orbital Region.
Attrahens aurem. Levator palpebrae superioris.
Retrahens aurem. Rectus superior.
342
MUSCLES AND FASCIA.
Eectus inferior.
Rectus internus.
Rectus externus.
Obliquus superior.
Obliquus inferior.
5. Nasal Region.
Pyramidalis nasi.
Levator labii superioris alteque nasi.
Dilatator naris posterior.
Dilatator naris anterior.
Compressor nasi.
Compressor narium minor.
Depressor alse nasi.
6. Superior Maxillary Region.
Levator labii superioris.
Levator anguli oris.
Zj'gomaticus major.
Zygomaticus minor.
7. Inferior Maxillary Region.
Levator labii inferioris.
Depressor labii inferioris.
Depressor anguli oris.
8. Intermaxillary Region.
Orbicularis oris.
Buccinator,
Risorius;
9. Temporo-maxillary Region.
Masseter.
Temporal.
10. Ptery go-maxillary Region.
Pterygoideus externus.
Pterygoideus internus.
L Ceanial Region — Occipito-feontalis.
Dissection (Fig. 242). The head being shaved, and a block placed beneath the back of the
neck, make a vertical incision through the skin from before backwards, commencing at the root
of the nose in front, and terminating behind at the occipital protuberance; make a second incision
Fig. 242.— Dissection of the Head, Face, and Neck.
'1 J}isseciionoJ' ^ZMS*
2.3.of AURICULAR RECIOW
/j-.S.G.of FACE
^^^B' \ ^.s. of n^cH
in !i lioriznntal direction along (ho forehead and round the side of the head, from the anterior to
the posterior extremity of the preceding. Raise the skin in front from the subjacent muscle from
hrdow upwards; this must he done with extreme care, removing the integument from the outer
Kurface of the vessels and the nerves which lie between the two.
The superficial fascia in tlie cranial region is a firm, dense layer, intimately
adherent to the integument, and to the Occipito-frontalis and its tendinous apo-
neurosis; it is continuous, behind, with the superficial fascia at the back part of
the neck; and, laterally, is continued over the temporal a])oneurosis : it contains
between its layers iIk; sninll muscles of the auricle, and the superficial temporal
vessels and superficial nerves.
CRANIAL REGION.
343
The Occiinto-frontalis (Fig. 243) is a broad musculo-fibrous layer, whicli covers
the whole of one side of the vertex of the skull, from the occiput to the eyebrow.
It consists of two muscular slips, separated by an intervening tendinous apo-
neurosis. The occipital portion^ thin, quadrilateral in form, and about an inch
Fig. 243.— Muscles of tlie Head, Face, and Neck.
COR p. U GAT 0
and a half in length, arises from the outer two-thirds of the superior curved line
of the occipital bone, and from the mastoid portion of the temporal. Its fibres
of origin are tendinous, but they soon become muscular, and ascend in a parallel
direction to terminate in the tendinous aponeurosis. ^]iq frontal, portion is thin,
of a quadrilateral form, and intimately adherent to the skin. It is broader, its
fibres are longer, and their structure paler than the occipital portion. Its inter-
nal fibres are continuous with those of the Pyramidalis nasi. Its middle fibres
become blended with the Corrugator supercilii and Orbicularis: and the outer
fibres are also blended with the latter muscle over the external angular process.
344 MUSCLES AND FASCIA.
From this attacliment, the fibres are directed upwards and join the aponeurosis
below tlie coronal suture. The inner margins of the frontal portions of the two
muscles are joined together for some distance above the root of the nose ; but
between the occipital portions there is a considerable though variable inter v^al.
The cqjoneurosis covers the upper part of the vertex of the skull, being con-
tinuous across the middle line with the aponeurosis of the opposite muscle.
Behind, it is attached, in the interval between the occipital origins, to the occi-
j^ital protuberance and superior curved lines above the attachment of the
Trapezius ; in front, it forms a short angular prolongation between the frontal
portions : and on each side, it has connected with it the AttoUens and Attrahens
aurem muscles; in this situation it loses its aponeurotic character, and is con-
tinued over the temporal fascia to the zygoma by a layer of laminated areolar
tissue. This aponeurosis is closely connected to the integument by a dense
fibro-cellular tissue, which contains much granular fat, and in which ramiiy
the numerous vessels and nerves of the integument; it is loosely connected with
the pericranium by a quantity of loose cellular tissue, which allows of a con-
siderable degree of movement of the integument.
Nerves. The frontal portion of the Occipito-frontalis is supplied by the facial
nerve; its occipital portion by the posterior auricular branch of the facial, and
sometimes by the occipitalis minor.
Actions. The frontal portion of the muscle raises the eyebrows and the skin
over the root of the nose; at the same time throwing the integument of the
forehead into transverse wrinkles, a predominant expression in the emotions of
delight. By bringing alternately into action the occipital and frontal portions,
the entire scalp may be moved from before backwards.
2. Auricular Region. (Fig. 243.)
Attollens Aurem. Attrahens Aurem,
Eetrahens Aurem.
These three small muscles are placed immediately beneath the skin around
the external ear. In man, in whom the external ear is almost immovable, they
are rudimentary. They are the analogues of large and important muscles in
some of the mammalia.
Dissection. This requires considernWe care, and slionld be performed in llie following' manner :
— To expose the Attollens aui'em, draw the pinna or broad part of the ear downwards, when a
tense band will be felt beneath the sUin, passing from the side of the head to the upper part of
the concha; by dividing the skin over the tendon, in a direction from below upwards, and then
reflecting it on each side, the muscle is exposed. 'I'o bring into view the Attrahens aurem, draw
the helix backwards by means of a hook, when the muscle will be made tense, and may be ex-
posed in a similar manner to the preceding. To expose the Eetrahens aurem, draw the pinna
forwards; when the muscle being made tense may be felt beneath the skin, at its insertion into
the back part of the concha, and may be exposed in the same manner as the other muscles.
The Attollens Aurem., the largest of the three, is thin, and fan-shaped: its fibres
arise from the aponeurosis of the Occipito-frontalis, and converge to be inserted
by a thin, flattened tendon into the U2:)per part of the cranial surface of the
pinna.
Rdations. Externally., with the integument; internally ., w\\h. the temporal
aponeurosis.
The Attrahens Avrem, the smallest of the three, is thin, fan-shaped, and its
fibres pale and indistinct; they arise from the lateral edge of the aponeurosis of
the Occipito-rroiilalis, and <'()iiverge to bo inserted int(^ a projection on ihc front
of the lielix.
Relations. Externally^ with the skin ; ivlcrnalh/^ Avith the temporal fascia,
which separates it from tlie tem))oral artery and vein.
The Retrali.ens Aurem, consists of two or three fleshy fasciculi, which arise
from tlic mastoid portion of the tcnnporal bone by sliort aponeurotic fibres.
They are inserted into the lower part of the cranial surhice of the concha.
PALPEBRAL REGION. 345
Relations. Externally, witli tlie integument ; internally, with the mastoid
portion of tlie temporal bone.
Nerves. The Attollens aurem is supplied by the occipitalis minor ; the Attra-
hens aurem, by the facial ; and the Retrahens aurem, by the posterior auricular
branch of the facial.
Actions. In man, these muscles possess very little action; the Attollens aurem
slightly raises the ear ; the Attrahens aurem draws it forwards and upwards ;
and the Eetrahens aurem draws it backwards.
3. Palpebkal Region. (Fig. 243.)
Orbicularis Palpebrarum. Levator Palpebrse Superioris.
Corrugator Supercilii. Tensor Tarsi.
Dissection (Fig. 242). In order to expose the muscles of the face, continue tlie longitudinal
incision, made in the .dissection of the Occipito-frontalis, down the median line of the face to the
tip of the nose, and from this point onwards to the upper lip; and carry another incision along
the margin of the lip to the angle of the mouth, and transversely across the face to the angle of
the jaw. Then make an incision in front of the external ear, from the angle of the jaw upwards,
to join the transverse incision made in exposing the Occipito-frontalis. These incisions include
a square-shaped flap, which should be removed in the direction marked in the figure, with care,
as the muscles at some points are intimately adherent to the integument.
The Orbicularis Paljjehrarum is a sphincter muscle, which surrounds the
circumference of the orbit and eyelids. It arises from the internal angular
process of the frontal bone, from the nasal process of the superior maxillary in
front of the lachrymal groove, and from the anterior surface and borders of a
short tendon, the tendo palpebrarum, placed at the inner angle of the orbit.
From this origin, the fibres are directed outwards, forming a broad, thin, and
flat layer, which covers the eyelids, surrounds the circumference of the orbit,
and spreads out over the temple, and downwards on the cheek, becoming blended
with the Occipito-frontalis and Corrugator supercilii. The palpebral portion
(oiliaris) of the Orbicularis is thin and pale; it arises from the bifurcation of
the tendo palpebrarum, and forms a series of concentric curves, which are united
on the outer side of the eyelids at an acute angle by a cellular raphe, some being
inserted into the external tarsal ligament and malar bone. The orbicular portion
(orbicularis latus) is thicker and of a reddish color: its fibres are well developed,
and form complete ellipses.
Relations. By its superficial surface, with the integument. By its deep surface,
above, with the Occipito-frontalis and Corrugator supercilii, with which it is
intimately blended, and with the supra-orbital vessels and nerve; below, it
covers the lachrymal sac, and the origin of the Levator labii superioris, and
the Levator labii snperioris alseque nasi muscles. Internally, it is occasionally
blended with the Pyramidalis nasi. Externally, it lies on the temporal fascia.
On the eyelids, it is separated from the conjunctiva by a fibrous membrane and
the tarsal cartilages.
The tendo palpehrarum, (tendo oculi) is a short tendon, about two lines in
length and one in breadth, attached to the nasal process of the superior maxil-
lary bone in front of the lachrymal groove. Crossing the lachrymal sac, it
divides into two parts, each division being attached to the inner extremity of
the corresponding tarsal cartilage. As the tendon crosses the lachrymal sac,
a strong aponeurotic lamina is given off from the posterior surface, which
expands over the sac, and is attached to the ridge on the lachrymal bone. This
is the reflected aponeurosis of the tendo palpebrarum.
The Corrugator Supercilii is a small, narrow, pyramidal muscle, placed at the
inner extremity of the eyebrow, beneath the Occipito-frontalis and Orbicularis
palpebrarum muscles. It arises from the inner extremity of the superciliary
ridge ; from whence its fibres pass upwards and outwards, to be inserted into
the under surface of the orbicularis, opposite the middle of the orbital arch.
Relations, By its anterior surface, with the Occipito-frontalis and Orbicularis
346 MUSCLES. AND FASCIA.
•V
palpebrariTm muscles. Bj its •posterior surface^ with tlie frontal bone and supra-
trochlear nerve. 'Ittfe.
The Levator Palpehrse will be described witlJW|li^ muscles of ftig^'orbital region.
The Tensor Tarsi is a small thin muscle, about 'three lines in breadth and six
in length, situated at the inner side of the orbit, behind the tendo oculi. It arises
from the crest and adjacent part of the orbital surface of the lachrymal bone,
and passing across the lachrymal sac, divides into two slips, which cover the
lachrymal canals, and are inserted into the tarsal cartilages near the puncta
lachrymalia. Its fibres appear to be continuous with those of the palpebral
portion of the Orbicularis ; it is occasionally very indistinct.
Nerves. The Orbicularis palpebrarum, Corrugator supercilii, and Tensor tarsi
are supplied by the facial nerve. -^ /^:'
Actions. The Orbicularis palpebrarum is the sphincter JB^cle of the eyelids.
The palpebral portion acts involuntarily in closing the IMle^' and independently
of the orbicular portion, which is subject to the will. When- the entire muscle
is brought into action, the integument of the foreheadi.itemple, and cheek is
drawn inwards towards the inner angle of the eye, ana the eyelids are firmly
closed. The Levator palpebroB is the direct antagonist of this muscle ; it raises
the upper eyelid and exposes the globe. The Corrugator supercilii draws the
eyebrow downwards and inwards, producing the vertical wrinkles of the fore-
head. This muscle may be regarded as the principal agent in the expression of
grief. The Tensor tarsi draws the eyelids and the extremities of the lachrymal
canals inwards, and compresses thcin against the surface of the globe of the eye ;
thus placing them in the most favorable situation for receiving the tears. It
serves, also, to compress the lachrymal sac.
4. Orbital Region. (Fig. 244.)
Levator Palpebras Superioris. Rectus Internus.
Rectus Superior. Rectus Bxternus.
Rectus Inferior. Obliquus Superior.
Obliquus Inferior.
Dissection. To open the cavity of the orbit, remove the skull-cap and brain ; then paw through
the frontal bone at the inner extremity of the supraorbital ridge, and externally at its junction
with the malar. Break in pieces the thin roof of the orbit by a few slight blows ot the hammer,
and take it away; drive forward the superciliary portion of the frontal bone by a smart stroke,
l)ut do not remove it, as that would destroy the pulley of the Obliquus superior. When the
fragments are cleared away, the periosteum of the orbit will be exposed ; this being removed,
together with the fat which fills the cavity of the orbit, the several muscles of this region can be
examined. The dissection will be facilitated by distending the globe of the eye. In order to
effect this, puncture the optic nerve near tha eyeball, with a curved needle, and push the needle
onwards into the globe ; insert the point of a blow-pipe through this aperture, and force a little
air into the cavity of the eyeball ; then apply a ligature round the nerve, so as to prevent the air
escaping. The globe being now drawn forwards, the muscles will be put upon the stretch.
The Levator Palpehrve Superioris is thin, flat, and triangular in shape. It
arises from the under surface of the lesser wing of the sphenoid, immediately in
front of the optic foramen ; and is inserted, by a broad aponeurosis, into the
upper border of the superior tarsal cartilage. At its origin, it is narrow and
tendinous ; but soon becomes broad and fleshy, and finally terminates in a broad
a[)oncnrosis.
lielations. By its upper snrface.^ with the frontal nerve and artery, the peri-
osteum of tlie orbit ; and, in front, with the inner snrface of the broad tarsal
ligament. By its under surface^ with the Superior rectus; and in the lid, with
the conjnnctiva. A small branch of the third nerve enters its under surface.
The Rectus .svperior^ the tliinncst and narrowest of the four Recti, arises from
the upper margin of the o|)tic foramen, benealh the Levator Palpebral, and
Sitpcrior oblirpu;, and from the fibrons sheath of tlu; ojitic nerve : and is inserted,
by a tendinous expansion, into tlie sclerotic coat, aljout three or four lines irom
the margin of the cornea.
ORBITAL REGION.
347
Relations. By its upper surface^ witli the Levator Palpebrae. By its under
surface^ with the optic nerve, the ophthahnic artery, the nasal nerve, and the
branch of the third nerve, which supplies it ; and, in front, with the tendon of
the Superior oblique, and the globe of the eye.
Fig. 244.— Muscles of the Ria-bt Orbit.
Fig. 245. — The relative position and attach-
ment of the Muscles of the Left Eyeball.
Hirtu^ tSfujoerutr
Xi'i'ato r
C'lliciuas Superior
Mcctus Injcruyr
•llccul
JiO-W£r Mt^ad
The Inferior and Internal Recti arise by a common tendon (the ligament of
Zinn), which is attached round the circumference of the optic foramen, except at
its upper and outer part. The External
rectus has two heads : the upper one arises
from the outer margin of the optic fora-
men immediately beneath the Superior
rectus ; the lower head, partly from the
ligament of Zinn, and partly from a small
pointed process of bone on the lower
margin of the sphenoidal fissure. Each
muscle passes forward in the position
implied by its name, to be inserted, by a
tendinous expansion (the tunica alhu-
ginea), into the sclerotic coat, about three
or four lines from the margin of the cornea.
Between the two heads of the External
rectus is a narrow interval, through which pass the third, nasal branch of the
fifth and sixth nerves, and the ophthalmic vein. Although nearly all of these
muscles present a common origin, and are inserted in a similar manner in the
sclerotic coat, there are certain differences to be observed in them, as regards
their length and breadth. The Internal Eectus is the broadest ; the External,
the longest ; and the Superior, the thinnest and narrowest.
The Superior Ohlique is a fusiform muscle, placed at the upper and inner side
of the orbit, internal to the Levator palpebras. It arises about a line above the
inner margin of the optic foramen, and, passing forwards to the inner angle of the
orbit, terminates in a rounded tendon, which plays in a ring or pulley, formed
by fibro-cartilaginous tissue attached to a depression beneath the internal angular
process of the frontal bone, the contiguous surfaces of the tendon and ring being
lined by a delicate synovial membrane, and inclosed in a thin fibrous investment.
The tendon is reflected backwards and outwards beneath the Superior rectus to
the outer part of the globe of the eye, and is inserted into the sclerotic coat,
midway between the cornea and entrance of the optic nerve, the insertion of the
muscle lying between the Superior and External recti.
•348 MUSCLES AND FASCIiE.
Relations. Bj its ^ipioer surface^ with tlie periosteum covering the roof of the
orbit, and the fourth nerve. Tlie tendon, where it lies on tlie globe of the eye,
is covered by the Superior rectus. By its under surface, with the nasal nerve,
and the upper border of the Internal rectus.
The Inferior Oblique is a thin, narrow muscle, placed near the anterior margin
of the orbit. It arises from a depression in the orbital plate of the superior
maxillary bone, external to the lachrymal groove. Passing outwards and back-
wards beneath the Inferior rectus, and between the eyeball and the External
rectus, it is inserted into the outer part- of the sclerotic coat between the Supe-
rior and External rectus, near the tendon of insertion of the Superior oblique.
Relations. By its upper surface, with the globe of the eye, and with the
Inferior rectus. By its under surface, with the periosteum covering the floor
of the orbit, and with the external rectus. Its borders look forwards and back-
wards; the poster.or one receives a branch of the third nerve.
JSferves. The Levator palpebrse. Inferior oblique, and all the recti excepting
the External, are supplied by the third nerve; the Superior oblique, by the
fourth ; the External rectus, by the sixth.
Actions. The Levator palpebree raises the upper ej^elid, and is the 'direct
antagonist of the Orbicularis palpebrarum. The four Kecti muscles are attached
in such a manner to the globe of the eye, that, acting singly, they will turn it
either upwards, downwards, inwards, or outwards, as expressed by their names.
If any two Recti act together, they carry the globe of the eye in the diagonal of
these directions, viz., upwards and inwards, upwards and outwards, downwards
and inwards, or downwards and outwards. The movement of circumduction,
as in looking round a room, is performed by the alternate action of the four
Recti. By some anatomists, these muscles have been considered the chief
agents in adjusting the sight at different distances, by compressing the globe,"
and so lengthening its antero-posterior diameter. The Oblique muscles rotate
the eyeball on its antero-posterior axis, this kind of movement being required
for the correct viewing of an object, when the head is moved laterally, as from
shoulder to shoulder, in order that the picture may fall in all respects on the
same part of the retina of each eye.^
Surrp'cal Anatomy. The position aiul exact point of insertion of llie tendons of the Tnternnl
and External recti ninscles into the globe should be carefully examined from the front of the
eyeball, as the surgeon is often required to divide one or the other muscle for the cure of
strabismus. In convergent strabismus, which is the most common form of the disease, the eye is
turned inwards, requiring the division of the Internal rectus. In the divergent form, which is
more rare, the eye is turned outwards, the External rectus being especially implicated. The
deformity produced in either case is to be remedied by division of one or the other muscle. The
operation is thus effected : the lids are to be well separated ; the eyeball being drawn outwaids,
the conjunctiva should be raised by a pair of forceps, and divided immediately beneath the lower
border Of the tendon of the Internal rectus, a little behind its insertion into the sclerotic; the
submucous aref>litr tissue is then divided, and into the small aperture thus made, a blunt hook is
passed upwards l)etween the muscle and the globe, and the tendon of the muscle and conjunctiva
covering it. divided by a pair of blunt-pointed scissors. Or the tendon may be divided by a sub-
conjunctival incision, one blade of the .scissors being passed upwards between the tendon and the
conjunctiva, and the other between the tendon and the sclerotic. The student, when dissecting
these niuscles, should remove on one side of the subject the conjunctiva from the front of the eye,
in order to sco more accurately the position of the tendons, while on the opposite side the opera-
tion may b<' performed.
' " On the Ohh'r/nc MnarleH nf the Eyo. in Man and Vertebrate Animals," by John Strutiiers.
M.I>.. " Ana./fimiral and Pln/siolocjical Observations.'' For a more full account of the various
co-ordinated aetions of the muscles of a single eye and of both eyes thnii our space allows, the
reader may lie referred to Dr. M. Foster's Text-book of Physiology, pp. 38r)-3bb.
NASAL REGION. 349"
5. Nasal Region. (Fig. 243.)
Pyramidalis Nasi.
Levator Labii Superioris Alseque Nasi.
Dilatator Naris Posterior.
Dilatator Naris Anterior.
Compressor Nasi.
Compressor Narium Minor.
Depressor Alse Nasi.
Tlie Pyram.idalis Nasi is a small pyramidal slip, prolonged downwards from
the Occipito-frontalis upon tlie side of the nose, where it becomes tendinous and
blends with the Compressor nasi. As the two muscles descend, they diverge,
leaving an angular interval between them.
Relations. By its upper surface^ with the skin. By its under surface^ with
the frontal and nasal bones.
The Levator Lahii Superioris Alaeque Nasi is a thin triangular muscle, placed
by the side of the nose, and extending between the inner margin of the orbit
and upper lip. It arises by a pointed extremity from the upper part of the
nasal process of the superior maxillary bone, and passing obliquely downwards
and outwards, divides into two slips, one of which is inserted into the cartilage
of the ala of the nose ; the other is prolonged into the upper lip, becoming
blended with the Orbicularis and Levator labii superioris proprius.
Relations, In front, with the integument ; and with a small part of the Orbi-
cularis palpebrarum above.
Lying upon the superior maxillary bone, beneath this muscle, is a longitudinal
muscular fasciculus about an inch in length. It is attached by one end near
the origin of the Compressor nasi, and by the other to the nasal process about
an inch above it; it was described by Albinus as the " Musculus anomalus," and
by Santorini, as the "Phomboideus."
The Dilatator Naris Posterior is a small muscle, which is placed partly
beneath the proper elevator of the nose and lip. It arises from the margin of
the nasal notch of the superior maxilla, and from the sesamoid cartilages, and
is inserted into the skin near the margin of the nostril.
The Dilatator Naris Anterior is a thin delicate fasciculus, passing from the
cartilage of the ala of the nose to the integument near its margin. This muscle
is situated in front of the preceding.
The Compressor Nasi is a small, thin, triangular muscle, arising by its apex
from the superior maxillary bone, above and a little external to the incisive
fossa ; its fibres proceed upwards and inwards, expanding into a thin aponeurosis
which is attached to the fibro-cartilage of the nose, and is continuous on the
bridge of the nose with that of the muscle of the opposite side, and with the
aponeurosis of the Pyramidalis nasi.
The Compressor Narium Minor is a small muscle, attached by one end to the
alar cartilage, and hy the other to the integument at the end of the nose.
The Depressor Alse Nasi is a short, radiated muscle, ai'ising from the incisive
fossa of the superior maxilla; its fibres ascend to be inserted into the septum,
and back part of the ala of the nose. This muscle lies between the mucous
membrane and muscular structure of the lip.
JSIerves. All the muscles of this group are supplied by the facial nerve.
Actions. The Pyramidalis nasi draws down the inner angle of the eyebrows;
by some anatomists it is also considered as an elevator of the ala, and, conse-
quently, a dilator of the nose. The Levator labii superioris alseque nasi draws
upwards the upper lip and ala of the nose ; its most important action is upon
the nose, which it dilates to a considerable extent. The action of this muscle
produces a marked influence over the countenance, and it is the principal agent
in the expression of contempt. The two Dilatatores nasi enlarge the aperture
350 MUSCLES AND FASCIiE.
of tlie nose, and tlie Compressor nasi appears to press upon tlie nose so as to
increase its breadth, and thus tends rather to open than to close the nostrils.
The Depressor alee nasi is a direct antagonist of the preceding muscles, drawing
the ala of the nose downwards, and thereby constricting the aperture of the
nares.
6. Superior Maxillary Eegion. (Fig, 243.)
Levator Labii Superioris. Zygomaticus Major.
Levator Anguli Oris. Zygomaticus Minor.
The Levator Lahii Superioris (proprius) is a thin muscle of a quadrilateral form.
It arises from the lower margin of the orbit immediately above the infraorbital
foramen, some of its fibres being attached to the superior maxilla, others to the
malar bone ; its fibres converge to be inserted into the muscular substance of the
upper lip.
Relations. By its superficial surface^ with the lower segment of the Orbicu-
laris palpebrarum ; below, it is subcutaneous. By its deep surface^ it conceals
the origin of the Compressor nasi and Levator anguli oris muscles, and the
infraorbital vessels and nerves, as they escape from the infraorbital foramen.
The Levator Anguli Oris arises from the canine fossa, immediately below the
infraorbital foramen ; its fibres incline downwards and a little outwards, to be
inserted into the angle of the mouth, intermingling with those of the Zygomatici,
the Depressor anguli oris, and the Orbicularis.
Relations. By its superficial surface., with the Levator labii superioris and the
infraorbital vessels and nerves. By its deep surface., with the superior maxilla,
the Buccinator, and the mucous membrane.
The Zygomcdicus Major is a slender fasciculus, which arises from the malar
bone, in front of the zygomatic suture, and, descending obliquely downwards
and inwards, is inserted into the angle of the mouth, where it blends with the
fibres of the Orbicularis and Depressor anguli oris.
Relations. By its superficial surface., with the subcutaneous adipose tissue. By
its deep surface., with the malar bone, and the Masseter and Buccinator muscles.
The Zygomaticus Minor arises from the malar bone, immediately behind the
maxillary suture, and, passing downwards and inwards, is continuous with the
outer margin of the Levator labii superioris. It lies in front of the preceding.
Relations. By its superficial surface., with the integument and the Orbicularis
})alpebrarum above. By its deep surface., with the Levator anguli oris.
Nerves. This group of muscles is supplied by the facial nerve.
Actions. The Levator labii superioris is the proper elevator of the upper lip,
carrying it at the same time a little outwards. The Levator anguli oris raises
the angle of the mouth and draws it inwards ; whilst the Zygomatici raise the
upper lip and draw it somewhat outwards, as in laughing.
7. Inferior Maxillary Eegion. (Fig. 243.)
Levator Labii Inferioris (Levator menti).
Depressor Labii Inferioris (Quadratus menti).
Depressor Anguli Oris (Triangularis menti).
DruHP.clion. Tlic muscles in this rcf^ion may be dissected by mukinjr a vertical incision tlirongh
the integument fi'Dni the niarfjin of the lower lip to the chin: a second incision should then be
carried along ihe margin of the lower jaw as far as the angle, and the integument carefully
removed in the direction shown in Fig. 242.
Tlic Levator Lahii hifcrioris {Lc.va.tor menti) is to bc'dissectcd by everting the
lower lip and raising llic mucous membrane. It is a small conical fasciculus,
placed on the side of the frrjcnum of the lower lip. It arises from the incisive
fossa, external to the sympliysis of llic lower jaw : its fibres descend to be inserted
into the integument of the chin.
INTERMAXILLARY REGION". 351
Relations. On its inner surface^ with tlie mncoiis membrane ; in the median
line^ it is blended with the muscle of the opposite side; and on its outer side^ with
the Depressor labii inferioris.
The Depressor Lahii Inferioris [Quadratus menti) is a small quadrilateral
mnscle, situated at the outer side of the preceding. It arises from the external
oblique line of the lower jaw, between the symphysis and mental foramen, and
passes obliquely upwards and inwards, to be inserted into the integument of the
lower lip, its fibres blending with the Orbicularis, and with those of its fellow of
the opposite side. It is continuous with the fibres of the Platysma at its origin.
This muscle contains much yellow fat intermingled with its fibres.
Relations. By its superficial surface^ with part of the Depressor anguli oris,
and with the integument, to which it is closely connected. By its deep surface^
with the mental vessels and nerves, the mucous membrane of the lower lip, the
labial glands, and the Levator menti, with which it is intimately united.
The Depressor Anguli Oris {Trial igularis menti) is triangular in shape, arising,
by its broad base, from the external oblique line of the lower jaw, from whence
its fib:^.es pass upwards, to be inserted, by a narrow fasciculus, into the angle of
the mouth. It is continuous with the Platysma at its origin, and with the Orbi-
cularis and Pisorius at its insertion, and some of its fibres are directly continuous
with those of the Levator anguli oris.
Relations. By its superficial surface.^ with the integument. By its deep surface.^
with the Depressor labii inferioris and Buccinator.
Nerves. This group of muscles is supplied by the facial nerve.
Actions. The Levator labii inferioris raises the lower lip, and protrudes it
forwards, and at the same time wrinkles the integument of the chin. The
Depressor labii inferioris draws the lower lip directly downwards and a little
outwards. The Depressor anguli oris depresses the angle of the mouth, being
the antagonist to the Levator anguli oris and Zygomaticus major ; acting with
these muscles, it will draw the angle of the mouth directly backwards.
8. Intermaxillaey Region.
Orbicularis Oris. Buccinator. Risorius.
Difisedion. The dissection of these Mnsctes may be considerably facilitated by filling the
cavity of the mouth with tow. so as to distend the cheeks and lips ; the mouth should then be
closed by a few stitches, and the integument carefully removed from the surface.
The Orbicularis Oris is a sphincter muscle, elliptic in form, composed of con-
centric fibres, which surround the orifice of the mouth. It consists of two thick
semicircular planes of muscular fibre, which interlace on either side with those
of the Buccinator and other muscles inserted into the lips. On the free margin
of the lips the muscular fibres are continued uninterruptedly from one lip to the
other, around the corner of the mouth, forming a roundish fksciculus of fine pale
fibres closely approximated. To the outer part of each segment some special
fibres are added, by which the lips are connected directly with the maxillary
bones and septum of the nose. The additional fibres for the upper segment
consist of four bands, two of which (Accessorii orbicularis superiores) arise from
the alveolar border of the superior maxilla, opposite the incisor teeth, and arch-
ing outwards on each side, are contimious at the angles of the mouth with the
other muscles inserted into this part. The two remaining muscular slips, called
the Naso-labialis, connect the upper lip to the septum of the nose: as they
descend from the septum, an interval is left between them, which corresponds
to that left by the divergence of the accessory portions of the Orbicularis above
described. It is this interval which forms the depression seen on the surface
of the skin beneath the septum of the nose. The additional fibres for the lower
segment (Accessorii orbicularis inferiores) arise from the inferior maxilla, exter-
nally to the Levator labii inferioris, and arch outwards to the angles of the
mouth, to join the Buccinator and the other muscles attached to this part.
352 MUSCLES AND FASCIJ5.
Belations. By its superficial surface^ witli the integument, to wliicli it is closely
connected. By its deep surface, with the buccal mucous membrane, the labial
glands, and coronary vessels. By its outer circumference, it is blended with the
numerous muscles which converge to the mouth from various parts of the face.
Its inner circumference is free, and covered by the mucous membrane.
The Buccinator is a broad, thin muscle, quadrilateral in form, which occupies
the interval betAveen the jaws at the side of the face. It arises from the outer
surface of the alveolar processes of the upper and lower jaws, corresponding to
the three molar teeth; and, behind, from the anterior border of the ptery go-
maxillary ligament. The fibres converge towards the angle of the mouth,
where the central fibres intersect each other, those from below being continuous
Avith the upper segment of the Orbicularis oris; and those from above with the
inferior segment; the highest and lowest fibres continue forward uninterruptedly
into the corresponding segment of the lip, without decussation.
Relations. By its superficial surface, behind, with a large mass of fat, which
separates it from the ramus of the lower jaw, the Masseter, and a small portion
of the Temporal muscle ; anteriorly, with the Zygomatici, Risorius, Levator
anguli oris, Depressor anguli oris, and Steno's duct, which pierces it opposite
the second molar tooth of the upper jaw ; the facial artery and vein cross it
from below upwards; it is also crossed by the branches of the facial and buccal
nerve. By its internal surface, with the buccal glands and mucous membrane
of the mouth.
The ptery go-maxillary ligament separates the Buccinator muscle from the
Superior constrictor of the pharynx. It is a tendinous band, attached by one
extremity to the apex of the internal pterygoid plate, and by the other to the
])osterior extremity of the internal oblique line of the lower jaw. Its inner
surface corresponds to the cavity of the mouth, and is lined by mucous mem-
brane. Its outer surface is separated from the ramus of the jaw by a quantity
of adipose tissue. Its posterior harder gives attachment to the Superior con-
strictor of the pharynx : its anterior border, to the fibres of the Buccinator.
The Risorius {Santorini) consists of a narrow bundle of fibres, which arises in
the fascia over the Masseter muscle, and passing horizontally forwards, is inserted
into the angle of the mouth, joining with the tibres of the Depressor anguli oris.
It is placed superficial to the Platysma, and is broadest at its outer extremity.
This muscle varies much in its size and form.
Nerves. The Orbicularis oris is supplied by the facial, the Buccinator by the
facial and by the buccal branch of the inferior maxillary nerve, which latter,
however, is by many anatomists regarded as a sensory nerve only.
Actions. The Orbicularis oris is the direct antagonist of all those muscles
which converge to the lips from the various parts of the face, its ordinary action
producing the direct closure of the lips; and its forcible action throwing the
integument into wrinkles, on account of the firm connection between the latter
and the surface of the muscle. The Buccinators contract and compress the
checks, so that, during the process of mastication, tlie food is kept under the
immediate pressure of the teeth.
0. Temporo-maxillatiy Be^jon.
Masseter. ^\M^]M)ral.
Tlio Masseter has been abrady exposed by the removal of the integument frr-m
the side of the fa(;e (Fig. 248); it is a sliort tliick muscle, somewhat quadrilateral
in form, consisting of two portions, superficial and dee]-). The superficial porium,
the larger, arises by a thick tendinous aponeurosis from the niahar ]irocess of the
superior maxilla, and from the anterior two-lliirds of lhc lower border of the
zygomatic arch: ils fibres pass dowuwar<ls and backwards, lo be inserted into
the angle and lower half of the ramus of lhc jaw. The deep portion is much
TEMPORO-MAXILLARY REGION.
353
smaller, and more muscular in texture ; it arises from tlie posterior tliird of tlie
lower border and tlie whole of the inner surface of the zygomatic arch ; its fibres
pass downwards and forwards, to be inserted into the upper half of the ramus
and outer surface of the coronoid process of the jaw. The deep portion of the
muscle is partly concealed, in front, by the superficial portion ; behind, it is
covered by the parotid gland. The fibres of the two portions are united at their
insertion.
Relations. By its superficial surface^ with the integument; above, with the
Orbicularis palpebrarum and Zygomatici ; and with Steno's duct, the branches
of the facial nerve, and the transverse facial vessels, which cross it. By its deep
surface^ with the ramus of the jaw, and the Buccinator, from which it is separated
by a mass of fat. Its posterior margin is overlapped by the parotid gland. Its
anterior margin projects over the Buccinator muscle; and the facial artery lies
on it below.
The temporal fascia is seen, at this stage of the dissection, covering in the
Temporal muscle. It is a strong aponeurotic investment, affording attachment,
by its inner surface, to the superficial fibres of the muscle. Above, it is a single
layer, attached to the entire extent of the temporal ridge ; but below, where it
is attached to the zygoma, it consists of two layers, one of which is inserted into
the outer, and the other into the inner border of the zygomatic arch. A small
quantity of fat, the orbital branch of the temporal artery, and a filament from
the orbital branch of the superior maxillary nerva, are contained between these
two layers. It is covered, on its outer surface, by the aponeurosis of the
Occipito-frontalis, the Orbicularis palpebrarum, the Attollens and Attrahens
aurem muscles; the temporal vessels and nerves cross it from below upwards.
Fig. 246. — The Temporal Muscle, the Zygoma and Massetci* having been removed.
Dissection. In order to expose the Temporal muscle, remove the temporal fascia, which may
he effected by separating it at its attachment along the upper border of the zy.croma. and dis-
secting it upwards from the surface of the muscle. The zygomatic arch should then be divid d,
in front, at its junction with the malar bone; and. behind, near the external auditory meatus,
and drawn downwards with the Masseter, which should be detached from its insertion into the
ramus and angle of the jaw. The whole extent of the temporal muscle is then exposed.
The Temporal (Fig. 246) is a broad radiating muscle, situated at the side of
the head, and occupying the entire extent of the temporal fossa. It arises from
23
354
MUSCLES AND FASCIA.
the wliole of the temporal fossa, which extends from the external angular process
of the frontal in front, to the mastoid portion of the temporal behind; and from
the curved line on the frontal and parietal bones above, to the pterygoid ridge
on the great wing of the sphenoid below. It is also attached to the inner surface
of the temporal fascia. Its fibres converge as they descend, and terminate in an
aponeurosis, the fibres of which, radiated at its commencement, converge into a
thick and flat tendon, which is inserted into the inner surface, apex, and anterior
border of the coronoid process of the jaw, nearly as far forwards as the last molar
tooth.
Relations. By its superficial surface^ with the integument, the temporal fascia,
the aponeurosis of the Occipito-frontalis, the Attolens and Attrahens aurem
muscles, the temporal vessels and nerves, the zygoma and Masseter. By its deep
surface, with the temporal fossa, the External pterygoid and part of the Bucci-
nator muscles, the internal maxillary artery, its deep temporal branches, and the
temporal nerves.
Nerves. Both muscles are supplied by the inferior maxillary nerve.
Actions. These will be described with the muscles of the pterygo-maxillary
region.
10. Pterygo-maxillary Eegion. (Fig. 247.)
Internal Pterygoid. External Pterj^goid.
Dissection. The temporal muscle havino: been exa'.r.iiied, saw through the base of the coronoid
process, and draw it upwards, together with the 'I'emporal muscle, which should be detached from
the surface of the temporal fossa. Divide the ramus of the jaw just below the condyle, and ali-o,
by a transverse incision extending across the commencement of its lower third, just above the
dental foramen ; remove the fragment, and the Pterygoid muscles will be exposed.
Fig. 247.— The Pterygoid Muscles ; the Zygomatic Arch and a portion of the
Ramus of the Jaw havhijr been removed.
The Interval Pterycjoid is a thick quadrilateral muscle, and resembles the
Masseter, in form, structure, and the direction of its fibres. It arises from the
]-)torygoid fossa, being attached to tlic inner surface of the external pterygoid
plate, and 1o Ihc grooved surface of the ttiberosity of the palate bone; its fibres
pass downwards, outwards, and backwards, to be inserted, by strong tendinous
lavninre, into the lower and back part of theiimcr side of the ramus and angle of
the lower jaw, as high as the dental foramen.
MUSCLES AND FASCIA OF THE NECK. 355
Relations. By its external surface^ witli the ramus of the lower jaw, from
which it is separated, at its upper part, bj the External pterygoid, the internal
lateral ligament, the internal maxillary artery, and the dental vessels and nerves.
By its internal surface, with the Tensor palati, being separated from the Superior
constrictor of the pharynx by a cellular interval.
The External Pterygoid is a short thick muscle, somewhat conical in form,
which extends almost horizontally between the zygomatic fossa and the condyle
of the jaw. It arises from the pterygoid ridge on the great wing of the sphenoid,
and the portion of bone included between it and the base of the pterygoid process ;
from the outer surface of the external pterygoid plate ; and from the tuberosity
of the palate and superior maxillary bones. Its fibres pass horizontally back-
wards and outwards, to be inserted into a depression in front of the neck of the
condyle of the lower jaw, and into the corresponding part of the interarticular
fibro-cartilage. This muscle, at its origin, appears to consist of two portions
separated by a slight interval; hence the terms upper and lower head, sometimes
used in the description of the muscle.
Relations. By its external surface, with the ramus of the lower jaw, the internal
maxillary artery, which crosses it,^ the tendon of the Temporal muscle, and the
Masseter. By its internal surface, it rests against the upper part of the internal
pterygoid, the internal lateral ligament, the middle meningeal artery, and inferior
maxillary nerve ; by its iqjper border, it is in relation with the temporal and
masseteric branches of the inferior maxillary nerve.
Nerves. These muscles are supplied by the inferior maxillary nerve.
Actions. The Temporal, Masseter, and internal pterygoid raise the lower jaw
against the upper with great force. The superficial portion of the masseter, and
the Internal pterygoid, assist the External pterygoid in drawing the lower jaw
forwards upon the upper, the jaw being drawn back again by the deep fibres of
the Masseter, and posterior fibres of the Temporal. The external pterygoid
muscles are the direct agents in the trituration of the food, drawing the lower
O 7 0
jaw directly forwards, so as to make the lower teeth project beyond the upper.
If the muscle of one side acts, the corresponding side of the jaw is drawn forwards,
and, the other condyle remaining fixed, the symphysis deviates to the opposite
side. The alternation of these movements on the two sides produces trituration.
MUSCLES AND FASCIA OF THE NECK.
The muscles of the Neck may be arranged into groups, corresponding with
the region in which they are situated.
These groups are nine in number : —
1. Superficial Eegion. 6. Muscles of the Soft Palate.
2. Depressors of the Os Hyoides 7. Muscles of the Anterior Vertebral
and Larynx. Region.
3. Elevators of the Os Hyoides 8. Muscles of the Lateral Vertebral
and Larynx. Region.
4. Muscles of the Tongue. 9. Muscles of the Larynx.
5. Muscles of the Pharynx.
1. Superficial Region. Infra-hyoid Region.
Platysma myoides. 2. Depressors of the Os Hyoides and Larynx.
Sterno-cleido mastoid. Sterno-hyoid.
Sterno-thyroid.
Thyro-hyoid.
Omo-hyoid.
' This is the usual relation ; but in many cases the artery will be found below the muscle.
356
MUSCLES AND FASCIA,
Supra-hyoid Region.
3. Elevators of the Os Ihjoides and
Larynx. Depressors of the Lower Jaw.
Digastric.
Stylo-hyoid.
Mylo-hyoid.
Geuio-liyoid.
Lingual Llegion.
4. Muscles of the Tongue.
Genio-hyo-glossus.
Hyo-glossus.
Lingualis.
Stylo-glossus.
Palato-giossus.
Pharyngeal Re(jion.
5. Muscles of the Pharynx.
Constrictor inferior.
Constrictor medins.
Constrictor superior.
Stylo-pliaryngevis.
Palato-pharyngeus.
Palatal Region.
6. Muscles of the Soft Palate.
Levator palati.
Tensor palati.
Azygos uvulae.
Palato-giossus.
Palato-pharyngeus.
7. Muscles of the Anterior Vertebral
Region.
Pectus capitis anticus major.
Pectus capitis anticus minor.
Pectus lateralis.
Longus colli.
8. Muscles of the Lateral Vertebral
Region.
Scalenus anticus.
Scalenus medius.
Scalenus posticus.
9. Muscles of the Larynx.
Included in tlie description of the
Larynx.
1. Superficial Cervical Pegion.
Platysma Mvoides,
Sterno-cleido-mastoid.
Dissection. A block having- been placed at the back of the neck, and the face turned to the
side opposite to that to be dissected, so as to place the parts npon the stretch, make two trans-
verse incisions: one from the chin, along* the margin of the lower jaw. to the mastoid process; and
the other along the upper border of the clavicle. Connect these by an oblique incision made in
the course of the Sterno-mastoid muscle, from the mastoid process to the sternum ; the two flaps
of integument having been removed in the direction shown in Fig. 242, the superficial iascia will
be exposed.
The superficial cervical fascia is exposed on the removal of the integument
from the side of the neck ; it is an extremely thin aponeurotic lamina, which is
hardly demonstrable as a separate membrane. Beneath it are found the Platysma
myoides muscle, the external jugular vein, and some superficial branches of the
cervical plexus of nerves.
The Platysma Myoides (Fig. 2-i3) is a broad thin plane of mnscular fibres,
placed immediately beneath the skin on each side of the neck. It arises from
the clavicle and acromion, and from the fascia covering the upper part of the
Pectoral, Deltoid, and Trapezius muscles; its fibres proceed obliquely upwards
and inwards along the side of neck, to be inserted into the lower jaw beneath
the external oblique line, some passing forwards to the angle of the mouth, and
others becoming lost in the cellular tissue of the face. The most anterior fibres
interlace, in front of the jaAV, with the fibres of the muscle of the op]iosite side;
those next in order become blended with the Depressor labii inferioris and the
Depressor angnli oris; others are prolonged upon the side of the check, and
interlace, near the angle of the mouth, with the muscles in this sitnation, and
may occjisionally be traced to the Zygomatic muscles, or to the margin of the
Orbicularis palpebrarum. Beneath tljc Platysma, the externiil jngular vein may
be seen descending rrf)m the angle of the jaw to lhc clavicle. It is essential to
remember the direction of the fibres of the Platysma, in connection with the
operation of bleeding from this vcs.sel ; \'nv i('lhc point of the lancet is introduced
in the direction of the muscular fibres, the orifice made will be filled up by the
SUPERFICIAL CERVICAL REGION. 357
contraction of the muscle, and blood will not flow; but if tbe incision is made
across the course of the fibres, thej will retract, and expose the orifice in the
vein, and so facilitate the flow of blood.
Relations. By its external surface^ with the integument, to which it is united
closely below, but more loosely above. By its internal surface^ with the Pecto-
ralis major. Deltoid, and Trapezius, and with the clavicle. In the neck^ with the
external and anterior jugular veins, the deep cervical fascia, the superficial
branches of the cervical plexus, the Sterno-mastoid, Sterno-hyoid, Omo-hyoid,
and Digastric muscles. In front of the Sterno-mastoid, it covers the sheath of
the carotid vessels ; and behind it, the Scaleni muscles and the nerves of the
brachial plexus. On the /ace, it is in relation with the parotid gland, the facial
artery and vein, and the Masseter and Buccinator muscles.
The deep cervical fascia is exposed on the removal of the Platysma myoides.
It is a strong fibrous layer, which invests the muscles of the neck, and incloses
the vessels and nerves. It commences, as an extremely thin layer, at the back
part of the neck, where it is attached to the spinous processes of the cervical
vertebra, and to the ligamentum nuchse ; and, passing forwards to the posterior
border of the Sterno-mastoid muscle, divides into two layers, one of which passes
in front, and the other behind that muscle. These join again at the anterior
border of the Sterno-mastoid ; and, being continued forwards to the front of the
neck, blend with the fascia of the opposite side. The superficial layer of the
deep cervical fascia (that which passes in front of the Sterno-mastoid), if traced
upwards, is found to pass across the parotid gland and Masseter muscle, forming
the parotid and masseteric fascia, and is attached to the lower border of the
zygoma, and more anteriorly to the lower border of the body of the jaw; if the
same layer is traced downwards, it is seen to pass to the upper border of the
clavicle and sternum, being pierced just above the former bone by the external
jugular vein. In the middle line of the neck, the fascia is thin above, and con-
nected to the hyoid bone; but it becomes thicker below, and divides, just below
the thyroid gland, into two layers, the more superficial of which is attached to
the upper border of the sternum and interclavicular ligament ; the deeper and
stronger layer is connected to the posterior border of that bone, covering in the
Sterno-hyoid and Sterno-thyroid muscles. Between these two layers is a little
areolar tissue and fat, and occasionally a small lymphatic gland. The deep layer
of the cervical fascia (that which lies behind the posterior surface of the Sterno-
mastoid) sends numerous prolongations, which invest the muscles and vessels of
the neck ; if traced upwards, a process of the fascia, of extreme density, is found
passing behind and to the inner side of the parotid gland, to be attached to the
base of the styloid process and angle of the lower jaw, termed the stylo-maxillary
ligament; if traced downwards and outwards, the fascia will be found to inclose
the posterior belly of the Omo-hyoid muscle, binding it down by a distinct pro-
cess, which descends to be inserted into the clavicle and cartilage of the first rib.
The deep layer of the cervical fascia also assists in forming the sheath which
incloses the common carotid artery, internal jugular vein, and pneumogastric
nerve. There are fibrous septa intervening between each of these parts, which,
however, are included together in one common investment. More internally, a
thin layer is continued across the trachea and thyroid gland, beneath the Sterno-
thyroid muscles ; and at the root of the neck this may be traced, over the large
vessels, to be continuous with the fibrous layer of the pericardium.
The Sterno-mastoid or Sterno-cleido-mastoid (Fig. 248) is a large thick muscle,
which passes obliquely across the side of the neck, being inclosed between the
two layers of the deep cervical fascia. It is thick and narrow at its central part,
but is broader and thinner at each extremity. It arises, by two heads, from the
sternum and clavicle. The sternal portion is a rounded fasciculus, tendinous in
front, fleshy behind, which arises from the upper and anterior part of the first
piece of the sternum, and is directed upwards, outwards, and backwards. The
clavicular portion arises from the inner third of the superior border of the clavicle,
Jo8
MUSCLES AND FASCIA.
being composed of fleshy and aponeurotic fibres; it is directed abnost vertically
upwards. These two portions are separated from one another, at their origin,
by a triangular cellular interval ; but become gradually blended, below the
middle of the neck, into a thick rounded muscle, which is inserted, by a strong
Fio'. 248. — Muscles of the Neck, and Boundaries of the Triangles
tendon, into the outer surface of the mastoid process, from its apex to its supe-
rior border, and by a thin aponeurosis into the outer two-thirds of the superior
curved line of the occipital bone. The Sterno-mastoid varies much in its extent
of attachment to the clavicle : in one case the clavicular may be as narrow as
the sternal portion; in another, as much as three inches in breadth. When the
clavicular origin is broad, it is occasionally subdivided into numerous slips,
separated by narrow intervals. More rarely, the corresponding margins of the
Sterno-mastoid and Trapezius have been found in contact. In the application
of a ligature to the third part of the subclavian artery, it will be necessary, where
the muscles come close together, to divide a portion of one or of both.
T])is muscle divides the quadrilateral space at the side of the neck into two
triangles, an anterior and a posterior. The boundaries of the anterior triangle
are in front, the median line of the neck ; above, the lower border of the body
of the jaw, and an imaginary line drawn from the angle of the jaw to the mas-
toid ])r()ccss; behind, the anterior border of the Sterno-mastoid muscle. Tlie
})oundarics of the 'poslcrior triangle are, in front, the jiosterior border of the
Sterno-rnastoid ; below, the upper border of the clavicle; behind, the anterior
margin of the Trapezius.'
The anterior edge of the muscle forms a very prominent ridge beneath the
skin which it is important to notice, as it forms a guide to the surgeon in
' 'I'lic anuloiiiy of tlicsc triangles will be more e.\actly described with that of the vessels of the
neck.
INFRA-HYOID REGION. 359
makiag the necessary incisions for ligature of tlie common carotid artery, and
for cesophagotomy.
Relations. By its superfimal surface^ witli the integument and Platysma, from
which it is separated by the external jugular vein, the superficial branches of
the cervical plexus, and the anterior layer of the deep cervical fascia. By its
deep surface^ it rests on the sterno-clavicular articulation, the deep layer of the
cervical fascia, the Sterno-hyoid, Sterno- thyroid, Omo-hyoid, the posterior belly
of the Digastric, Levator anguli scapulee, the Splenius and Scaleni muscles.
Below, it is in relation with the lower part of the common carotid artery, inter-
nal jugular vein, pneumogastric, descendens noni and communicans noni nerves,
and with the deep lymphatic glands; with the spinal accessory nerve, which
pierces its upper third, the cervical plexus, the occipital artery, and a part of
the parotid gland.
Nerves. The Platysma myoides is supplied by the facial and superficial
branches of the cervical plexus; the Sterno-cleido-mastoid by the spinal acces-
sory and deep branches of the cervical plexus.
Actions. The Platysma myoides produces a slight wrinkling of the surface of
the skin of the neck, in an oblique direction, where the entire muscle is brcraght
into action. Its anterior portion, the thickest part of the muscle, depresses the
lower jaw; it also serves to draw down the lower lip and angle of the mouth on
each side, being one of the chief agents in the expression of melancholy. The
Sterno-mastoid muscles, when both are brought into action, serve to depress the
head upon the neck, and the neck upon the chest. Either muscle, acting singh^
flexes the head, and (combined with the Splenius) draws it towards the shoulder
of the same side, and rotates it so as to carry the face towards the opposite side.
Surgical Anatomy. 'We relations of the sternal and clavicular parts of the Sterno-mastoid
should be carefully examined, as the surgeon is sometimes required to divide one or both por-
tions of the muscle in ivry neck. One variety of this distortion is produced by spasmodic con-
traction or rigidity of the Sterno-mastoid ; the head being carried down towards the shoulder of
the same side, and the face turned to the opposite side, and fixed in that position. When all
other remedies for the relief of this disease have failed, subcutaneous division of the muscle is
resorted to. 'I'his is performed by introducing a long narrow bistoury beneath it, about half an
inch above its origin, and dividing it from behind forwards whilst the muscle is put well upon the
stretch. There is seldom any difficulty in dividing the sternal portion. ]n dividing lhe clavicu-
lar portion care must be taken to avoid wounding the external jugular vein, which runs parallel
with the posterior border of the muscle in this situation.
2. Infea-hyoid Regio]st. (Figs. 248, 24:9.)
Depressors of the Os Hyoides and Larynx.
Sterno-hyoid. Thyro-hyoid.
Sterno-thyroid. Omo-hyoid.
Dissection. 'I'he muscles in this region may be exposed by removing the deep fascia from the
front of the neck. In order to see the entire extent of the Omo-hyoid, it is necessary to divide
the Sterno-mastoid at its centre, and turn its ends aside, and to detach the Trapezius from the
clavicle and scapula. This, however, should not be done unless the 'i'rapezius has been dis-
sected.
The Sterno-hyoid is a thin, narrow, riband-like muscle, which arises from the
inner extremity of the clavicle, and the upper and posterior part of the first
piece of the sternum; and, passing upAvards and inwards, is inserted, by short
tendinous fibres, into the lower border of the bodv of the os hyoides. This
muscle is separated, below, from its fellow by a considerable interval ; but they
approach one another in the middle of their course, and again diverge as they
ascend. It often presents, immediately above its origin, a transverse tendinous
intersection, like those in the Eectus abdominis.
Variations. This muscle sometimes arises from the inner extremity of the clavicle, and the
posterior sterno-clavicular ligament ; or from the sternum and this ligament: from either bone
alone, or from all these parts; and occasionally has a fasciculus connected with the cartilage of
the first rib.
360
MUSCLES AND FASCIA.
Relations. By its superficial surface., below, witli the sternum, tlie sternal end
of the clavicle, and the Sterno-mastoid ; and above, with the Platysma and deep
cervical fascia. By its deep surface^ with the Sterno-thyroid, Crico-thyroid, and
Thyro-hyoid muscles, the thyroid gland, the superior thyroid vessels, the crico-
thyroid and thyro-hyoid membranes.
The Sterno-thyroid is situated beneath the preceding muscle, but is shorter
and wider than it. It arises from the posterior surface of the first bone of the
sternum, below the origin of the sterno-hyoid, and occasionally from the edge
of the cartilage of the first rib; and is inserted into the oblique line on the side
of the ala of the thyroid cartilage. This muscle is in close contact with its
fellow at the lower part of the neck ; and is frequently traversed by a trans-
verse or oblique tendinous intersection, like those in the Eectus abdominis.
Variations. This muscle is sometimes continuous with the Thyrohyoid and Inferior constrictor
of the pharynx ; and a lateral prolongation from it sometimes passes as far as the os hyoides.
RelcUions. By its anterior surface., with the Sterno-hyoid, Omo-hyoid, and
Sterno-mastoid. By its posterior surface., from below upwards, with the trachea,
vena innominata, common carotid (and on the right side the arteria innominata),
the thyroid gland and its vessels, and the lower part of the larynx. The middle
thvroid vein lies along its inner border, a relation which it is important to
remember in the operation of tracheotomy.
Fig. 249.-
-Muscles of the Neck.
of-fr,^'
Anterior View.
ike a continuation
Tim Thyro-hyoid is a small quadrilateral muscle appearing lil
of the Sterno-thyroid. It arises from the oblique lino on the side of the thyroid
f.firtilap-o, and passes vertically upwards to be inserted into the lower border of
the bridy and greater cornu of tlic hyoid bone.
Rclaiiorta. By its external surface, with the St(M'no-hyoid and Omo-hyoid
muscles. By its intemnl svrface^ with the th\ioi(l cartiiage, the thyro-hyoid
membrane, and the superior laryngeal vessels and nerve.
SUPRA-HYOID REGION. 3G1
Tlie Omo-hyoid passes across the side of the neck, from the scapula to the
hyoid bone. It consists of two fleshy bellies, united by a central tendon. It
arises from the upper border of the scapula, and occasionally from the transverse
ligament which crosses the suprascapular notch; its extent of attachment to the
scapula varying from a few lines to an inch. From this origin, the posterior
belly forms a flat, narrow fasciculus, which inclines forwards across the lower
part of the neck, behind the Sterno-mastoid muscle, where it becomes tendinous ;
it then changes its direction, forming an obtuse angle, and the anterior belly
ascends almost vertically upwards, close to the outer border of the Sterno-hyoid,
to be inserted into the lower border of the body of the os hyoides, just external
to the insertion of the Sterno-hyoid. The tendon of this muscle, which varies
much in its length and form in different subjects, is held in its position \)j a
process of the deep cervical fascia, which includes it in a sheath, and is prolonged
down to be attached to the cartilage of the first rib. It is by this means that
the angular form of the muscle is maintained.
This muscle subdivides each of the two large triangles at the side of the neck
into two smaller triangles : the two posterior ones being the posterior superior or
occipital^ and the posterior inferior or subclavian; the two anterior, the anterior
superior or superior carotid, and the anterior inferior or inferior carotid triangle.
Relations. By its superficial surface, with the Trapezius, Subclavius, the
clavicle, the Sterno-mastoid, deep cervical fascia, Platysma, and integument.
By its deep surface, with the Scaleni, brachial plexus, sheath of the common
carotid artery, and internal jugular vein, the descendens noni nerve, Sterno-
thyroid and Thyro-hyoid muscles.
Nerves. The Thyro-hyoid is supplied by the hypoglossal ; the other muscles
of this group by branches from the loop of communication between the descen-
' dens and communicans noni.
Actions. These muscles depress the larynx and hyoid bone, after they have
been drawn up with the pharynx in the act of deglutition. The Omo-hyoid
muscles not only depress the hyoid bone, but carry it backwards, and to one or
the other side. They are also tensors of the cervical fascia. The Thyro-hyoid
may act as an elevator of the thyroid cartilage, when the hyoid bone ascends,
drawing upwards the thyroid cartilage behind the os hyoides.^
3. SuPRA-HYOiD Region-. (Figs. 248, 249.)
Elevators of the Os Hyoides — ^Depressors of the Lower Jaw. '
Digastric. Mylo-hyoid.
Stylo-hyoid. Genio-hyoid.
Dissection. To dissect these muscles, a block should he placed beneath the back of the neck,
and the head drawn backwards, and retained in that position. On the removal of the deep fascia,
t.ie muscles are at once exposed.
The Digastric consists of two fleshy bellies united by an intermediate rounded
tendon. It is a small muscle, situated below the side of the body of the lower
jaw, and extending, in a curved form, from the side of the head to the symphysis
of the jaw. The 'posterior helly, longer than the anterior, arises from the digastric
groove on the inner side of the mastoid process of the temporal bone, and passes
downwards, forwards, and inwards. The anterior helly, being reflected upwards
and forwards, is inserted into a depression on the inner side of the lower border
of the jaw, close to the symphysis. The tendon of the muscle perforates the
Stylo-hyoid, and is held in connection with the side of the body of the hyoid
bone by an aponeurotic loop, lined by a synovial membrane. A broad aponeu-
rotic layer is given off from the tendon of the Digastric on each side, which is
' It is this action of the Thyro-hyoid muscle which, as Dr. Buchanan has pointed out, "causes
or permits the folding back of the epiglottis over the upper orifice of the larynx." — Journ. of
Anat. and Phys., 2d series, No. III. p. 255.
362 MUSCLES AND FASCIA.
attaclied to tlie body and great corim of tlie liyoid bone: this is termed tlie
su]?ra-kyoid aponeurosis. It forms a strong layer of fascia between tbe anterior
portion of tbe two muscles, and a firm investment for the otlier muscles of the
supra-hyoid region which lie deeper.
The Digastric muscle divides the anterior superior triangle of the neck into
two smaller triangles ; the upper, or submaxillary, being bounded, above, by the
lower jaw and mastoid process; below, by the two bellies of the Digastric muscle:
the lower, or superior carotid triangle, being bounded, above, by the posterior
belly of the Digastric ; behind, by the Sterno-mastoid ; below, by the Omo-hyoid.
Relations. By its superjicial surface^ with the Platysma, Sterno-mastoid and
Trachelo-mastoid, part of the Stylo-hyoid muscle, and the parotid and submaxil-
lary glands. By its deep surface^ the anterior belly lies on the Mylo-hyoid ; the
posterior belly on the Stylo-glossus, Stylo-pharyngeus, and Hyo-giossus muscles,
the external carotid artery, and its lingual and facial branches, the internal
carotid artery, internal jugular vein, and hypoglossal nerve.
The Stylo-hyoid is a small, slender muscle, lying in front of, and above, the
posterior belly of the Digastric. It arises from the middle of the outer surface
of the styloid process; and, passhig downwards and forwards, is inserted into
the body of the hyoid bone, just at its junction with the greater cornu, and
immediately above the Omo-hyoid. This muscle is perforated, near its insertion,
by the tendon of the Digastric.
Relations. The same as the posterior belly of the Digastric.
The Digastric and Stylo-hyoid should be removed, in order to expose the next
muscle.
The Mylo-hyoid is a flat triangular muscle, situated immediately beneath the
anterior belly of the Digastric, and forming, with its fellow of the opposite side,
a muscular floor for the cavity of the mouth. It arises from the whole length-
of the mylo-hyoid ridge, from the symphysis in front to the last molar tooth
behind. The posterior fibres pass obliquely forwards, to be inserted into the
body of the os hyoides. The middle and anterior fibres are inserted into a
median fibrous raph^, where they join at an angle with the fibres of the opposite
muscle. This median raphd is sometimes wanting ; the muscular fibres of the
two sides are then directly continuous with one another.
Relations. By its cutaneous surface., with the Platysma, the anterior belly of
the Digastric, the supra-hyoid fascia, the submaxillary gland, and submental
vessels. By its deep or superior surface., with the Genio- hyoid, part of the Hyo-
glossus, and Stylo-glossus muscles, the lingual and gustatory nerves, the sub-
lingual gland, and the buccal mucous membrane. Wharton's duct curves
round its posterior border in its passage to the mouth.
Dissection. The Mylo-hyoid should now be removed, in order to expose the muscles which
lie beneath; this is effected by detaching- it from its attachments to the hyoid bone and jaw, and
separating it by a vertical incision from its fellow of the opposite side.
The Genio-hyoid is a narrow, slender muscle, situated immcdiatel}'' beneath^
the inner border of the preceding. It arises from the inferior genial tubercle on
the posterior surface of the symphysis of the jaw, and passes downwards and
backwards, to be inserted into the anterior surface of the body of the os hyoides.
''J^liis muscle lies in close contact with its felloAv of the opposite side, and increases
slightly in breadth as it descends.
Relations. It is covered by the mylo-hyoid, and lies on the Genio-hyo-glossus.
Nerves. The Digastric is supplied, its anterior belly, by the mylo-hyoid branch
of the inferior dental ; its posterior belly, by the facial; the Stylo-hyoid, by the
facial; the Mylo-hyoid, by the mylo-hyoid bninch of the inferior dental; tlic
Genio-hyoid, by tlie hypoglossal.
Actions. This gronji of miisclcs ])crronns two very imiiorlant- actions, Tlicy
' This refers to the depth of the mnsfles from the skin in dissecting-. In Ihe erect position of
the body each of these muiicies lies above the preceding.
LINGUAL REGION.
363
raise the hyoid bone, and witli it tlie base of the tongue, during the act of
deglutition ; or, when the hyoid bone is lixed by its depressors and those of
tiie larynx, they depress the lower jaw. During the first act of deglutition,
when the mass is being driven from the mouth into the pharynx, the hyoid
bone, and with it the tongue, is carried upwards and forwards by the anterior
belly of the Digastric, the Mylo-hyoid, and Genio-hyoid muscles. In the second
act, when the mass is passing through the pharynx, the direct elevation of the
hyoid bone takes place by the combined action of all the muscles; and after
the food has passed, the hyoid bone is carried upwards and backwards by the
posterior belly of the Digastric and Stylo-hyoid muscles, which assist in pre-
venting the return of the morsel into the mouth.
4. Lingual Regiojst.
Muscles of the Tongue.
Genio-hyo-glossus. Lingualis.
Hyo-glossus. Stylo-glossus.
Palato-giossus.
Dissection. After completing the dissection of the preceding muscles, saw through the lower
jaw just external to the symphysis. Then draw the tongue forwards, and attach it, by a stitch,
to the nose ; and its muscles, which are thus put on the stretch, may be examined.
The Genio-hyo-glossus has received its name from its triple attachment to
the jaw, hyoid bone, and tongue; it is a thin, flat, triangular muscle, placed
Fig. 250.— Muscles of the Tongue. Left Side.
vertically on either side of the middle line, its apex corresponding with its
point of attachment to the lower jaw, its base with its insertion into the tongue
364
MUSCLES AND FASCIiE.
and hyoid bone. It arises by a short tendon from the superior genial tubercle
on the inner side of the symphysis of the jaw, immediately above the Genio-
hyoid ; from this point, the muscle spreads out in a fan-like form, the inferior
fibres passing downwards, to be inserted into the upper part of the body of the
hj^oid bone, a few being continued into the side of the pharynx; the middle
iibres passing backwards, and the superior ones upwards and forwards, to be
attached to the whole length of the under surface of the tongue, from the base
to the apex.
Relations. By its internal surface^ it is in contact with its fellow of the opposite
side, from which it is separated, at the back part of the tongue, by the fibrous
septam, which extends through the middle of the organ. By its external surface.,
with the Lingualis, Hyo-giossus, and Stylo- glossus, the lingual artery and hypo-
glossal nerve, the gustatory nerve, and sublingual gland. By its u'pper harder.,
with the mucous membrane of the floor of the mouth (frasnum linguae). By its
lower horder., with the Genio-hyoid.
The Hyo-ylossus is a thin, flat, quadrilateral muscle, which arises from the side
of the body, the lesser cornu, and whole length of the greater cornu of the hyoid
bone, and passing almost vertically upwards, is inserted into the side of the
tongue, between the Stylo-glossus and Lingualis. Those fibres of this muscle
which arise from the body, are directed upwards and backwards, overlapping
those from the greater cornu, which are directed obliquely forwards. Those from
the lesser cornu extend forwards and outwards along the side of the tongue,
under cover of the portion arising from the body.
The difference in the direction of the fibres of this muscle, and their separate
origin from different parts of the hyoid bone, led Albinus and other anatomists
to describe it as three muscles, under the names of the Basio-giossus, the Kerato-
giossus, and the Chondro-glossus.
Relations. By its external surface., with the Digastric, the Stylo-hyoid, Stylo-
glossus, and Mylo-hyoid muscles, the gustatory and hypoglossal nerves, Wharton's
duct, and the sublingual gland. By its cfeep surface., with the Genio-hyo-glossus,
Lingualis, and Middle constrictor, the lingual vessels, and the glosso-pharyngeal
nerve.
The greater part of the muscular substance of the tongue is formed by its in-
trinsic muscle, the Lingualis., inferior, superficial, transverse and vertical. The
Fig. 25L
-A Longitudinal Section of the Tongue near the middle line, to show the Superficial
Lingualis and the Intrinsic Vertical Fibres.
inferior lingualis (Figs. 250, 251) is a loiigihi.lJiKil band of nniscnhir fi1)rcR situ-
ated on the under snrfjicc! of tlic tongue, lying in the interval between tlie Ilyo-
glossuH and Genio-liyo-glossus, and extending from the base to the apex of the
organ. Posteriorly, some of its fibres arc lost in the base of the tongue, and
others arc occasionally attached to the hyoid bone. It blends with the fibres of the
LINGUAL REGION.
060
Stylo-glossus, in front of tlie Hjo-glossus, and is continned forwards as far as the
apex of tlie tongue. It is in relation, by its under surface, with the ranine artery.
The superficial lingualis (Fig. 251) consists of fibres running more or less longi-
tudinally along the back of the tongue beneath the mucous membrane, and
Fig. 252. — A Transverse Section of tlie Tongue, showing the various Intrinsic and Extrinsic
Muscles in their relative positions. 'I'he Intrinsic Vertical Fibres and the-Rauine Artery are
removed on one side, and shown on the other.
i.viy|ii,i\
>\
blending with the deeper fibres. At the sides of the tongue these fibres are
crossed by those of the palato- and hyo-glossus. Between these two are found
transverse fibres (Fig. 252) which arise from the median septum, and blend with
the fibres of the palato-glossus and other muscles, as well as a large number of
vertical fibres. The vertical fibres are arranged somewhat parallel with those
of the genio-hyo-glossus, with which many of those near the middle line are
continuous; they extend from the upper to the lower surface of the tongue, decus-
sating with the fibres of the other muscles, and especially with the transverse.
The interstices of the muscular fibres are filled with a large quantity of fat and
glandular tissue.
A very distinct fibrous septum exists betvv^een the two halves of the tongue, so
that the anastomoses between the two lingual arteries are not very free, a fact
often illustrated by injecting one half of the tongue with colored size, while the
other is left uninjected, or is injected of a dififerent color.
The Stylo-glossus^ the shortest and smallest of the three styloid muscles, arises
from the anterior and outer side of the styloid process, near its centre, and from
the stylo-maxillary ligament, to which its fibres, in most cases, are attached by
a thin aponeurosis. Passing downwards and forwards, so as to become nearly
horizontal in its direction, it divides upon the side of the tongue into two por-
tions : one longitudinal, which is inserted along the side of the tongue, blending
with the fibres of the Lingualis in front of the Hyo-glossus; the other oblique,
which overlaps the Hyo-glossus muscle, and decussates with its fibres.
delations. By its external surf ace, from, above downwards, with the parotid
gland, the Internal pterygoid muscle, the sublingual gland, the gustatory nerve,
and the mucous membrane of the mouth. By its internal surface, with the
tonsil, the Superior constrictor, and the Hyo-glossus muscle.
The Palato-glossus, or Constrictor Isthmi Faucium, although it is one of the
muscles of the tongue, serving to draw its base upwards during the act of deglu-
tition, is more nearly associated with the soft palate, both in its situation and
function; it will, consequently, be described with that group of muscles.
Nerves. The Palato-glossus is supplied by the palatine branches of Meckel's
ganglion; the Lingualis, according to some authors, by the chorda tympani; the
remaining muscles of this group, by the hypoglossal.
Actions. The movements of the tongue, although numerous and complicated,
may be understood by carefully considering the direction of the fibres of its
muscles. The Oenio-hyo-glossi, by means of their posterior and inferior fibres,
draw upwards the hyoid bone, bringing it and the base of the tongue forwards,
3G6
MUSCLES AND FASCIA.
so as to protrude tlie apex from tlie moutli. The anterior fibres will draw the
tongue back into the mouth. The whole length of these two muscles acting along
the middle line of the tongue will draw it downwards, so as to make it concave
from side to side, forming a channel along which fluids may pass towards the
pharynx, as in sucking. The Hyo-glossi muscles draw down the sides of the
tongue, so as to render it convex from side to side. The Linguales^ superficial
and inferior, by drawing downwards the centre and apex of the tongue, render
it convex from before backwards. The Palato-glossi draw the base of the tongue
upAvards, and the Stylo-glossi upwards and backwards.
5. Phaeyngeal Eegion".
Muscles of the Pharynx.
Constrictor Inferior,
Constrictor Medius.
Constrictor Superior.
Stylo-pharyngeus.
Palato-pharyngeus.
Dissection (Fig. 253). In order to examine tlie muscles of the pharynx, cut through the trachea
and oesophagus just above tke sternum, and draw them upwards by dividing the loose areolar
tissue connecting the pharynx with the front of the vertebral column. The parts being drawn well
forwards, apply the edge of the saw immediately behind the styloid processes, and saw the base
of the skull through from below upwards. 'I'he pharynx and mouth should then be stuffed with
tow, in order to distend its cavity and render the muscles tense and easier of dissection.
The Inferior Constrictor^ the most superficial and the thickest of the three
constrictors, arises from the side of the cricoid and thyroid cartilages. To the
cricoid cartilage it is attached in the
Fig. 253.
-Muscles of the Pharynx.
View.
External
interval between the crico-thyroid mus-
cle, in front, and the articular facet for
the thyroid cartilage behind. To the
thyroid cartilage it is attached to the
oblique line on the side of the great ala,
the cartilaginous surface behind it,
nearly as far as its posterior border,
and to the inferior cornu. From these
attachments, the fibres spread back-
wards and inwards, to be inserted into
the fibrous raphe in the posterior me-
dian line of the pharynx. The inferior
fibres are horizontal, and continuous
Avith the fibres of the oesophagus ; the
rest ascend, increasing in obliquity, and
overlap the Middle constrictor. The
superior laryngeal nerve passes near
the upper border, and the inferior, or
recurrent laryngeal, beneath the lower
border of this muscle, previous to theii"
entering the larynx.
Rclaimis. It is covered by a dense
cellular membrane which surrounds
the entire pharynx. Behind^ it is in
relation with the vertebral column and
the ]/)ngus colli muscle ; laterally^ with
the tliyroid gland, the common carotid
artery, and the Stcrno-tliyroid muscle;
by its internal surface^ with the Middle
constrictor, the Stylo-pharyngeus, Pa-
lato-pharyngeus, the pharyngeal aponeurosis, and the muccnis membrane of the
pliarynx.
PHARYNGEAL REGION. 367
Tlie Middle Constrictor is a flattened, fan-shaped muscle, smaller than the pre-
ceding, and situated on a plane anterior to it. It arises from the whole length
of the greater cornu of the hyoid bone, from the lesser cornu, and from the
stylo-hyoid ligament. The fibres diverge from their origin : the lower ones
descending beneath the Inferior constrictor, the middle fibres passing trans-
versely, and the upper fibres ascending and overlapping the Superior constrictor.
The muscle is inserted into the posterior median fibrous raphe, blending in the
middle line with that of the opposite side.
Belations. This muscle is separated from the Superior constrictor by the
glosso-pharyngeal nerve and the Stylo-pharyngeus muscle ; and from the Infe-
rior constrictor, by the superior laryngeal nerve. Behind, it lies on the vertebral
column, the Longus colli, and the Eectus anticus major. On each side it is in
relation with the carotid vessels, the pharyngeal-plexus, and some lymphatic
glands. ISTear its origin, it is covered by the Hyo-glossus, from which it is
separated by the lingual vessels. It lies upon the Superior constrictor, the
Stylo-pharyngeus, the Palato-pharyngeus, the pharyngeal aponeurosis, and the
mucous membrane.
The Siq^erior Constrictor is a quadrilateral muscle, thinner and paler than the
other constrictors, and situated at the upper part of the pharynx. It arises from
the lower third of the margin of the internal pterygoid plate and its hamular
process, from the contiguous portion of the palate boue and the reflected tendon
of the Tensor palati muscle, from the ptery go-maxillary ligament, from the
alveolar process above the posterior extremity of the mylo-hyoid ridge, and by
a few fibres from the side of the tongue in connection with the Genio-hyo-glos-
sus. From these points, the fibres curve backwards, to be inserted into the
median raphe, being also prolonged by means of a fibrous aponeurosis to the
pharyngeal spine on the basilar process of the occipital bone. The superior
fibres arch beneath the Levator palati and the Eustachian tube, the interval
between the upper border of the muscle and the basilar process being deficient
in muscular fibres, and closed by fibrous membrane.
Relations. By its outer surface, with the vertebral column, the carotid vessels,
the internal jugular vein, the three divisions of the eighth nerve and the ninth
nerve, the Middle constrictor which overlaps it, and the Stylo-pharyngeus. It
covers the Palato-pharyngeus and the tonsil, and is lined by the pharyngeal
aponeurosis and by mucous membrane.
The Stylo- pharyngeiis is a long, slender muscle, round above, broad and thin
below. It arises from the inner side of the base of the styloid process, passes
downwards along the side of the pharynx between the Superior and Middle con-
strictors, and spreads out beneath the mucous membrane, where some of its
fibres are lost in the Constrictor muscles, and others, joining with the Palato-
pharyngeus, are inserted into the posterior border of the thyroid cartilage. The
glosso-pharyngeal nerve runs on the outer side of this muscle, and crosses over
it in passing forward to the tongue.
Relations. Externally.^ with the Stylo-glossus muscle, the external carotid
artery, the parotid gland, and the Middle constrictor. Internally.^ with the inter-
nal carotid, the internal jugular vein, the Superior constrictor, Palato-pharyn-
geus and mucous membran-e.
Nerves. The muscles of this group are supplied by branches from the pharyn-
geal plexus and glosso-pharyngeal nerve, and the inferior constrictor, by an
additional branch from the external laryngeal nerve, and by the recurrent laryn-
geal.
Actions. When deglutition is about to be performed, the pharynx is drawn
upwards and dilated in difierent directions, to receive the morsel propelled into
it from the mouth. The Stylo-pharyngei, which are much further removed
from one another at their origin than at their insertion, draw the sides of the
pharynx upwards and outwards, its breadth in the antero-posterior direction
being increased by the larynx and tongue being carried forwards in their ascent.
368
MUSCLES AND FASCIA.
As soon as the morsel is received in tlie pharynx, tlie Elevator muscles relax,
the bag descends, and the Constrictors contract upon the morsel, and convey it
gradually downwards into the oesophagus. Besides its action in deglutition, the
pharynx also exerts an important influence in the modulation of the voice, es-
pecially in the production of the higher tones.
6. Palatal Eegion.
Muscles of the Soft Palate.
Levator Palati. Azygos Uvulse,
Tensor Palati. Palato-glossus.
Palato-Pharyngeus.
Dissection (Fig. 254). Lay open the pharynx from behind, by a vertical incision extending
from its upper to its lower part, and partially divide the occipital attachment by a transverse
incision on each side of the vertical one ; the posterior surface of the soft palate is then exposed.
Having fixed the uvula so as to make it tense, the mucous membrane and glands should be care-
fully removed from the posterior surface of the soft palate, and the muscles of this jiart are at
once exposed.
Fig. 234 — Muscles of the Soft Palate. The Pharynx being laid open from behind.
^ o A k a <j''
The Levator Palati is a long, thick, rounded muscle, placed on the outer side
of the jKj.stcrior uarcs. It arises from the under surface of the apex of the
petrous portion of the tcm]ooral bone, and from the adjoining cartilaginous por-
tion of tiic Eu.^tachian tube; after passing into the pliarynx, above the upper
concave margin of the Superior c(;n.s1rictor, it descends' obliquely downwards
PALATAL REGION. 369
and inwards, its fibres spreading out in tlie posterior surface of tlie soft palate
as far as tlie middle line, where they blend with those of the opposite side.
Relations. Externally^ with the Tensor palati and Superior constrictor.
Internally^ with the mucous membrane of the pharynx. Posteriorly^ with the
mucous lining of the soft palate. This muscle must be removed and the ptery-
• goid attachment of the Superior constrictor dissected away, in order to expose
the next muscle.
The Circumfiexus or Tensor Palati is a broad, thin, riband-like muscle, placed
on the outer side of the preceding, and consisting of a vertical and a horizontal
portion. The vertical portion arises by a broad, thin, and flat lamella from the
scaphoid fossa at the base of the internal pterygoid plate, its origin extending
as far back as the spine of the sphenoid ; it also arises from the anterior aspect
of the cartilaginous portion of the Eustachian tube ; descending vertically
between the internal pterygoid plate and the inner surface of the Internal ptery-
goid muscle, it terminates in a tendon which winds round the hamular process,
being retained in this situation by some of the fibres of origin of the Internal
pterygoid muscle, and lubricated by a bursa. The tendon or horizontal portion
then passes horizontally inwards, and expands into a broad aponeurosis on the
anterior surface of the soft palate, which unites in the median line with the
aponeurosis of the opposite muscle, the fibres being attached in front to the
transverse ridge on the horizontal portion of the palate bone.
Relations. Externally.^ with the Internal pterygoid. Internally^ with the
Levator palati, from which it is separated by the Superior constrictor, and the
internal pterygoid plate. In the Soft palate, its aponeurotic expansion is ante-
rior to that of the Levator palati, being covered by mucous membrane.
The Azygos Uvulae is not a single muscle, as implied by its name, but a pair
of narrow cylindrical fleshy fasciculi, placed side by side in the median line of
the soft palate. Each muscle arises from the posterior nasal spine of the palate
bone, and from the contiguous tendinous aponeurosis of the soft palate, and
descends to be inserted into the uvula.
Relations. Anteriorly^ with the tendinous expansion of the Levatores palati ;
behind^ with the mucous membrane.
The two next muscles are exposed by removing the mucous membranes from the pillars of the
soft palate throughout nearly their whole extent.
The Palato-glossus [Constrictor Isthord Faucium) is a small, fleshy fasciculus,
narrower in the middle than at either extremitj^-, forming, with the mucous
membrane covering its surface, the anterior pillar of the soft palate. It arises
from the anterior surface of the soft palate on each side of the uvula, and
passing downwards, forwards, and outwards in front of the tonsil, is inserted
into the side and dorsum of the tongue, where it blends Avith the fibres of the
Stylo-glossus muscle. In the soft palate, the fibres of this muscle are continuous
with those of the muscle of the opposite side.
The Palato-pharyngeus is a long, fleshy fasciculus, narrower in the middle
than at either extremity, forming, with the mucous membrane covering its sur-
face, the posterior pillar of the soft palate. It is separated from the preceding
by an angular interval, in which the tonsil is lodged. It arises from the soft
palate by an expanded fasciculus, which is divided into two parts by the Leva- '
tor palati. The anterior fasciculus, the thicker, lies in the soft palate between
the Levator and Tensor, and joins in the middle line the corresponding part of
the opposite muscle ; the posterior faciculus lies in contact with the mucous
membrane, and also joins with the corresponding muscle in the middle line.
Passing outwards and downwards behind the tonsil, the Palato-pharyngeus joins
the Stylo-pharyngeus, and is inserted with that muscle into the posterior border
of the thyroid cartilage, some of its fibres being lost on the side of the pharynx,
and others passing across the middle line posteriorly, to decussate with the
muscle of the opposite side.
24
370 MUSCLES AND FASCIiE.
Relations. In tlie soft palate, its anterior and posterior surfaces are covered
by mucous membrane, from wbicli it is separated by a layer of palatine glands.
By its superior border^ it is in relation with the Levator palati. Where it forms
the posterior pillar of the fauces, it is covered by mucous membrane, excepting
on its outer surface. In the pharynx it lies between the mucous membrane and
the Constrictor muscles.
Nerves. The Tensor palati is supplied by a branch from the otic ganglion ;
the Levator palati, and Azygos uvulae, by the facial, through the connection of
its trunk with the Yidian, by the petrosal nerves ; the other muscles, by the
palatine branches of Meckel's ganglion.
Actions. During the first act of deglutition, the morsel of food is driven back
into the fauces by the pressure of the tongue against the hard palate ; the base
of the tongue being, at the same time, retracted, and the larynx raised with the
pharynx, and carried forwards under it. During the second stage, the epiglottis
is pressed over the superior aperture of the larynx, and the morsel glides past
it; then the Palato-giossi muscles, the constrictors of the fauces, contract behind
the food ; the soft palate is slightly raised by the Levator palati, and made tense
by the Tensor palati; and the Palato-pharyngei contract, and come nearly
together, the uvula filling up the slight interval between them. By these means
the food is prevented passing into the upper part of the pharynx or the poste-
rior nares; at the same time, the latter muscles form an ioclined plane, directed
obliquely downwards and backwards, along which the morsel descends into the
lower part of the pharynx.
Surgical Anatomy. The muscles of the soft palate should be carefully dissected, the relations
they bear to the surrounding parts especially examined, and their action attentively studied upon
the dead subject, as the sur^-eon is required to divide one or more of these muscles in the opera-
tion of staphyloraphy. Sir W. Fergusson has shown, that in the congenital deficiency, called
cleft palate, the edges of the fissure are forcibly separated by the action of the Levatores palati
and Palato-pharyngei muscles, producing very considerable impediment to the healing process
after the performance of the operation for uniting their margins by adhesion ; he has, consequently,
recommended the division of these muscles as one of the most important steps in the operation.
This he effects by an incision made with a curved knife introduced behind the flap. The incision
is to be half-way between the hamular process and Eustachian tube, and perpendicular to a line
drawn between them. This incision perfectly accomplishes the division of the Levator palati.
The Palato-pharyngcus may be divided by cutting across the posterior pillar of the soft palate,
just below the tonsil, with a pair of blunt-pointed curved scissors ; and the anterior pillar may be
divided also. To divide the Levator palati, the plan recommended by Mr. Pollock is to be greatly
preferred. The flap being put upon the stretch, a double-edged knife is passed through the soft
palate, just on the inner side of the hamuhir process, and above the line of the Levator palati.
'i'he handle being now alternately raised and depressed, a sweeping cut is made along the poste-
rior surface of the soft palate, and the knife withdrawn, leaving only a small opening in the
mucous membrane on the anterior surface. If this operation is performed on the dead body, and
the parts afterwards dissected, the Levator palati will be found completely divided.
7. Vertebeal Region (Anterior).
Rectus Capitis Anticus Major. Rectus Lateralis.
Rectus Capitis Anticus Minor. Longus Colli.
The Rectus Capitis Anticus Major (Fig. 255), broad and thick above, narrow
below, appears like a continuation upwards of the Scalenus anticus. It arises
by four tendinous slips from the anterior tubercles of the transverse processes
<^f the third, fourth, fifth, and sixth cervical vcrtebrre, and ascends, converging
towards its fellow of the opposite side, to be inserted into the basilar process of
the occi])ital bone,
Rcldlions. By its anterior surface^ with tlie pharynx, the sympa,tlictic nerve,
and llic sheath inclosing the carotid artery, internal jugular vein, and pneumo-
gaatric nerve. By \{i>, posterior surface^ with the Longus colli, the Rectus anticus
minor, and the upper cervical vertebrce.
The Rectus Capilvs Anticus Minor is a sliort flat inusclc, situated immcrliately
behind the upper part of the preceding. It arises from the anterior surface of
ANTERIOR VERTEBRAL REGION.
371
tlie lateral mass of tlie atlas, and from the root of its transverse process, and
passing obliquely upwards and inwards, is inserted into the basilar process
immediately behind the preceding muscle.
Belations. By its anterior surface^ with the Rectus anticus major. By its
posterior surface^ with the front of the occipito-atlantal articulation. Externally^
with the superior cervical ganglion of the sympathetic.
Fig:. 255. — The Prevertebral Muscles.
The Rectus Lateralis is a short flat muscle, which arises from the upper surface
of the transverse process of the atlas, and is inserted into the under surface of
the jugular process of the occipital bone.
Relations. By its anterior surface^ with the internal jugular vein. By its
posterior surface^ with the vertebral artery. On its outer side lies the occiptal
artery.
The Longus Colli is a long flat muscle, situated on the anterior surface of the
spine, between the atlas and the third dorsal vertebra. It is broad in the middle,
narrow and pointed at each extremity, and consists of three portions, a superior
oblique, an inferior oblique, and a vertical portion. The superior oblique portion
arises from the anterior tubercles of the transverse processes of the third, fourth,
and fifth cervical vertebra; and, ascending obliquely inwards, is inserted by a
narrow tendon into the tubercle on the anterior arch of the atlas. The inferior
ohlique portion.^ the smallest part of the muscle, arises from the bodies of the first
two or three dorsal vertebrae ; and ascending obliquely outwards, is inserted into
the transverse processes of the fifth and sixth cervical vertebrae.
The vertical portion lies directly on the front of the spine, and is extended
372 MUSCLES AND FASCIA.
between the bodies of tlie lower three cervical and the upper three dorsal verte-
brae below, and the bodies of the second, third, and fourth cervical vertebrae
above.
Relations. Bj its anterior surface^ with the pharynx, the oesophagus, sympa-
thetic nerve, the sheath of the great vessels of the neck, the inferior thyroid
artery, and recurrent laryngeal nerve. By its posterior surface^ with the cervical
and dorsal portions of the spine. Its inner border is separated from the oppo-
site muscle by a considerable interval below ; but they approach each other
above.
8. Veetebral EEGioisr (Lateral).
Scalenus Anticus. Scalenus Medius.
Scalenus Posticus.
The Scalenus Anticus is a conical-shaped muscle, situated deeply at the side
of the neck, behind the Sterno-mastoid. It arises by a narrow, fiat tendon from
the tubercle on the inner border and upper surface of the first rib ; and, ascend-
ing almost vertically, is inserted into the anterior tubercles of the transverse
processes of the third, fourth, fifth, and sixth cervical vertebrae. The lower
part of this muscle separates the wsubclavian artery and vein : the latter being
in front, and the former, with the brachial plexus, behind.
Relations. In front^ with the clavicle, the Subclavius, Sterno-mastoid, and
Omo-hyoid muscles, the Transversalis colli, and ascending cervical arteries, the
subclavian vein, and the phrenic nerve. By its posterior surface^ with the pleura,
the subclavian artery, and brachial plexus of nerves. It is separated from the
Longus colli, on the inner side, by the vertebral artery.
The Scalenus Medius^ the largest and longest of the three Scaleni, arises, by
a broad origin, from the upper surface of the first rib, behind the groove for the
subclavian artery, as far back as the tubercle ; and, ascending along the side of
the vertebral column, is inserted, by separate tendinous slips, into the posterior
tubercles of the transverse processes of the lower six cervical vertebra. It is
separated from the Scalenus anticus by the subclavian artery below, and the
cervical nerves above.
Relations. By its anterior surface^ with the Sterno-mastoid ; it is crossed by
the clavicle, the Omo-hyoid muscle, and subclavian artery. To its outer side is
the Levator anguli scapulae, and the Scalenus posticus muscle.
The Scalenus Posticus^ the smallest of the three Scaleni, arises by a thin tendon
from the outer surface of the second rib, behind the attachment of the Serratus
magnus, and, enlarging as it ascends, is inserted, by two or three separate ten-
dons, into the posterior tubercles of the transverse processes of the lower two or
three cervical vertebrae. This is the most deeply placed of the three Scaleni,
and is occasionally blended with the Scalenus medius.
Nerves. The Eectus capitis anticus major and minor and the Rectus lateralis
are supplied by the suboccipital and deep branches of the cervical plexus ; the
Longus colli and Scaleni, by branches from the lower cervical nerves.
Actions. The Rectus anticus major and minor are the direct antagonists of
the muscles at the back of the neck, serving to restore the head to its natural
position after it has been drawn backwards. These muscles also serve to flex
the head, and, from their obliquity, rotate it, so as to turn the face to one or the
otlier side. The Longus colli will flex and slightly rotate the cervical portion
of the spine. The Scaleni muscles, taking their fixed point from below, draw
down the transverse processes of the cervical vertebrae, bending the spinal col-
umn to one or the other side. If the muscles of both sides act, the spine will be
kept erect. When they take their fixed point from above, they elevate the
first and second ribs, and arc, therefore, inspiratory muscles.
MUSCLES AND FASCIA OF THE TRUNK. 373
MUSCLES AND FASCIA OF THE TEUNK.
The m-ascles of tlie Trunk may be arranged in four groups : tlie muscles of
tlie Back, of the Abdomen, of the Thorax, and of the Perineeum.
Muscles of the Back.
The muscles of the Back are very numerous, and may be subdivided into five
layers : — •
First Layer. Longissimus dorsi.
Trapezius. Spinalis dorsi.
Latissimus dorsi.
Cervical Region.
Second Layer. - Cervicalis ascendens.
Levator anguli scapulae. Transversalis colli.
Rhomboideus minor. Trachelo-mastoid.
Ehomboideus major. Gomplexus.
Biventer cervicis.
Third Layer. Spinalis coUi.
Serratus posticus superior. I-i'ifth Layer
Serratus posticus inferior, ^ • • t i ' •
Q 1 • ^ •, • bemispmahs dorsi.
feplenius capitis. o ■ • t n-
Q T • iv feemispinaiis com.
Splenius coin. ,^ n^-i^j
^ Multindus spmae.
Fourth Layer. Rotatores spinas.
„ 7 ^ ^ , ^ . feupraspmaies.
bacrai and Lumbar Megions. Interspinales
Erector spinas. Extensor coccygis.
Intertransversales.
Dorsal Region. Rectus capitis posticus major.
Sacro-lumbalis. Rectus capitis posticus minor.
Musculus accessorius ad sacro- Obliquus capitis superior.
lumbalem. Obliquus capitis inferior.
First Layer.
Trapezius. Latissimus Dorsi.
Dissection (Fig. 256). Place the body in the prone position, with the arms extended over the
sides of the table, and the chest and abdomen supported by several blocks, so as to render the
muscles tense. Then make an incision along the middle line of the back, from the occipital pro-
tuberance to the coccyx. Make a transverse incision from the upper end of this to the mastoid
process ; and a third incision from its lower end, along the crest of the ilium to about its middle.
This large intervening space should, for convenience of dissection, be subdivided by a fourth inci-
sion, extending obliquely from the spinous process of the last dorsal vertebra, upwards and out-
wards, to the acromion process. This incision corresponds with the lower border of the Trapezius
muscle. The flaps of integument are then to be removed in the direction shown in the figure.
The_ Trapezius is a broad, flat, triangular muscle, placed immediately beneath
the skin, and covering the upper and back part of the neck and shoulders. It
arises from the inner third of the superior curved line of the occipital bone ;
from the ligamentum nuchas, the spinous process of the seventh cervical, and
those of all the dorsal vertebrae ; and from the corresponding portion of the
supraspinous ligament. From this origin, the superior fibres proceed downwards
and outwards, the inferior ones, upwards and outwards ; and the middle fibres,
horizontally ; and are inserted, the superior ones, into the outer third of the
posterior border of the clavicle ; the middle fibres into the inner margin of the
acromion process, and into the superior lip of the crest of the spine of the sca-
pula ; the inferior fibres converge near the scapula, and are attached to a
374
MUSCLES AND FASCIA.
Fig. 256.
-Dissection of the Muscles
of the Back.
triangular aponeurosis, wliicli glides over a smooth surface at tlie inner ex-
tremity of tlie spine, and is inserted into a tubercle at the outer part of the
surface. The Trapezius is fleshy in the greater
part of its extent, but tendinous at its origin
and insertion. At its occipital origin, it is
connected to the bone by a thin fibrous lamina,
firmly adherent to the skin, and wanting the
lustrous, shining appearance of aponeurosis.
At its origin from the spines of the vertebras,
it is connected to the bones by means of a
broad semi-elliptical aponeurosis, which occu-
pies the space between the sixth cervical and
the third dorsal vertebrse, and forms, with the
aponeurosis of the opposite muscle, a tendi-
nous ellipse. The rest of the muscle arises
by numerous short tendinous fibres. If the
Trapezius is dissected on both sides, the two
muscles resemble a trapezium, or diamond-
shaped quadrangle ; two angles corresponding
to the shoulders ; a third to the occipital pro-
tuberance ; and the fourth to the spinous pro-
cess of the last dorsal vertebra.
The clavicular insertion of this muscle va-
ries as to the extent of its attachment; it
sometimes advances as far as the middle of
the clavicle, and may even become blended
with the posterior edge of the Sterno-mastoid-
or overlap it. This shoiild be borne in mind
in the operation for tying the third part of
the subclavian artery.
Relations. By its superficial surface^ with
the integument, to which it is closely adherent
above, but separated below by an aponeurotic
lamina. By its deep surf ace., in the neck, with the Complexus, Splenius, Levator
anguli scapulae, and Ehomboideus minor; in the back, with the Ehomboideus
major, Supraspinatus, Infraspinatus, a small portion of the Serratus posticus
superior, the vertebral aponeurosis (which separates it from the Erector spinse),
and the Latissimus dorsi. The spinal accessory nerve passes beneath the
anterior border of this muscle, near the clavicle. The interior margin of its
cervical portion forms the posterior boundary of the posterior triangle of the
neck, the other boundaries being the Sterno- mastoid in front, and the clavicle
below.
The Liyamentum Nuchee (Fig. 257) is a thin band of condensed cellulo-fibrous
membrane, placed in the line of union between the two Trapezii in the neck. It
extends from the external occipital protuberance to the spinous process of the
Reventh cervical vertebra, where it is continuous with the supraspinous ligament.
From its anterior surface a fibrous slip is given off to the spinous process of each
of the cervical vertebrae, excepting the atlas, so as to form a septum between the
muscles on each side of the neck. In man, it is merely the rudiment of an im-
portant clastic ligament, which, in some of the lower animals, serves to sustain
the weight of the head.
The Latissimv.s Dorsi is a broad fiat muscle, which covers the lumbar and
the lower half of the dorsal regions, and is gradually contracted into a narrow
fasciculus at its insertion into the humerus. It arises by an apeneurosis from the
spinous processes of the six inferior dorsal, from those of the lumbar and sacral
vertcbrfo, and from the supraspinous ligament. Over the sacrum, the aponeurosis
of this muscle blends with the tendon of the Erector spinas. It also arises from
OF THE BACK.
375
Fig. 257.— M'-'sdes of the Back. On the Left Side is exposed the First Layer;
on the Right Side, the Second Layer and part of the Tliird.
376 MUSCLES AND FASCIAE.
the external lip of the crest of the ilium, behind the origin of the External
oblique, and by fleshy digitations from the three or four lower ribs, which are
interposed between similar processes of the External oblique muscle (Fig. 260,
p. 386). From this extensive origin the fibres pass in different directions, the
upper ones horizontally, the middle obliquely upwards, and- the lower vertically
upwards, so as to converge and form a thick fasciculus, which crosses the inferior
angle of the scapula, and occasionally receives a few fibres from it. The muscle
then curves around the lower border of the Teres major, and is twisted upon
itself, so that the superior fibres become at first posterior and then inferior, and
the vertical fibres at first anterior and then superior. It then terminates in a
short quadrilateral tendon, about three inches in length, which, passing in front
of the tendon of the Teres major, is inserted into the inner lip and into the
bottom of the bicipital groove of the humerus, and its insertion extends higher
on the humerus than that of the tendon of the Pectoralis major. The lower
border of the tendon of this muscle is united with that of the Teres major, the
surfaces of two being separated by a bursa ; another bursa is sometimes inter-
posed between the muscle and the inferior angle of the scapula.
A muscular slip, varying from 3 to 4 inches in length, and from | to f of an inch in breadth,
occasionally arises from the upper edge of the Latissimus dorsi, about the middle of the posterior
fold of the axilla, and crosses the axilla in front of the axillary vessels and nerves, to join the
under surface of the tendon of the Pectoralis major, the Coracobrachialis, or the fascia over the
Biceps. The position of this abnormal slip is a point of interest in its relation to the axillary
artery, as it crosses the vessel just above the spot usually selected for the application of a liga-
ture, and may mislead the surgeon during the operation. Tt may be easily recognized by the
transverse direction of its fibres. Dr. Struthers found it, in 8 out of 105 subjects, occurring seven
times on both sides.
Relations. Its superficial surface is subcutaneous, excepting at its upper part,
where it is covered by the Trapezius. By its deep surface^ it is in relation with
the Erector spinas, the Serratus posticus inferior, the lower intercostal muscles
and ribs, the Serratus magnus, inferior angle of the scapula, Ehomboideus major,
Infraspinatus, and Teres major. Its outer margin is separated below, from the
External oblique, by a small triangular interval ; and another triangular interval
exists between its upper border and the margin of the Trapezius, in which the
Intercostal and Ehomboideus major muscles are exposed.
Nerves. The Trapezius is supplied by the spinal accessory, and deep branches
of the cervical plexus ; the Latissimus dorsi by the long subscapular nerve.
Second Layer.
Levator Anguli Scapulce. Ehomboideus Minor.
Ehomboideus Major.
Difisertion. The Trapezius must be removed in order to expose the next layer ; to effect this,
detach the muscle from its attachment to the clavicle and spine of the scapula, and turn it back
towards the spine.
The Levator Anrjuli Hcapuloe is situated at the back part and side of the neck.
It arises by four tendinous slips from the posterior tubercles of the tTansverse
processes of the three or four upper cervical vertebrte ; these becoming fleshy
are united so as to form a flat muscle, which, passing downwards and backwards,
is inserted into the posterior border of the scapula, between the superior angle
and tlic triangular smooth surface at the root of the s]-)ine.
Jlehaions. By its superficial [anterior) surface^ with the integument, Trapezius,
and Sterno-mastoid. By its deep [posterior) surface^ with the S})lenius colli,
Transvcrsalis colli, Cervicalis ascendens, and Serratus posticus supcricu*, and
with the transvcrsalis colli and posterior scapular arteries.
The Rhornhoid.ens Minor arises from the ligamentum nuchse and spinous pro-
cesses of the seventh ccrviciil and first dorsal vertebrae. Passing downwards
and outwards, it is inserted into the margin of the triangular smooth surlacc at
OF THE BACK. 377
tlie root of tlie spine of tlie scapula. This small muscle is usually separated
from the Ehomboideas major by a slight cellular interval.
The Bhomhoideus Major is situated immediately below the preceding, the
adjacent margins of the two being occasionally united. It arises by tendinous
fibres from the spinous processes of the four or five upper dorsal vertebrae and
the supraspinous ligament, and is inserted into a narrow tendinous arch, attached
above to the triangular surface near the spine ; below, to the inferior angle, the
arch being connected to the border of the scapula by a thin membrane. When
the arch extends, as it occasionally does, but a short distance, the muscular fibres
are inserted into the scapula itself.
Relations. By their superficial [posterior) surface^ with the integument and
Trapezius; the Ehomboideus major, with the Latissimus dorsi. By their deep
{anterior) surface^ with the Serratus posticus superior, posterior scapular artery,
part of the Erector spinse, the intercostal muscles and ribs.
Nerves. These muscles are supplied by branches from the fifth cervical nerve,
and additional filaments from the deep branches of the cervical plexus are distri-
buted to the Levator anguli scapulae.
Actions. The movements effected by the preceding muscles are numerous, as
may be conceived from their extensive attachment. If the head is fixed, the
upper part of the Trapezius will elevate the point of the shoulder, as in
supporting weights; when the middle and lower fibres are brought into action,
a partial rotation of the scapula upon the side of the chest is produced. If the
shoulders are fixed, both Trapezii acting together will draw the head directly
backwards, or if only one acts, the head is drawn to the corresponding side.
The Latissimus Dorsi^ when it acts upon the humerus, draws it backwards
and downwards, and at the same time rotates it inwards. If the arm is fixed,
the muscle may act in various ways upon the trunk ; thus, it may raise the
lower ribs and assist in forcible inspiration, or if both arms are fixed, the two
muscles may assist the abdominal and great Pectoral muscles in drawing the
whole trunk forwards, as in climbing or walking on crutches.
The Levator Anguli Scapulae raises the superior angle of the scapula after it
has been depressed by the lower fibres of the Trapezius, whilst the Ehomboid
muscles carry the inferior angle backwards and upwards, thus producing a slight
rotation of the scapula upon the side of the chest. If the shoulder be fixed, the
Levator anguli scapulae may incline the neck to the corresponding side. The
Ehomboid muscles acting together with the middle and inferior fibres of the
Trapezius, will draw the scapula directly backwards towards the spine.
Thibd Layer.
Serratus Posticus Superior. Serratus Posticus Inferior,
o T • ( Splenius Capitis.
^P^^^^^^^IspleniusColli.
Dissection. To bring into view the third layer of muscles, remove the whole of the second,
together with the Latissimus dorsi ; by cutting through the Levator anguli scapute and Rhom-
boid muscles near their insertion, and reflecting^ them upwards, to expose the Serratus posticus
superior, dividing the Latissimus dorsi in the middle by a vertical incision carried from its upper
to its lower part, and reflecting the two halves of the muscle.
The Serratus Posticus Superior is a thin, flat, quadrilateral muscle, situated
at the upper and back part of the thorax. It arises by a thin and broad
aponeurosis from the ligamentum nuchge, and from the spinous processes of the
last cervical and two or three upper dorsal vertebrae. Inclining downwards and
outwards, it becomes muscular, and is inserted, by four fleshy digitations, into
the upper borders of the second, third, fourth, and fifth ribs, a little beyond
their angles,
Belations. By its superficial surface with the Trapezius, Ehomboidei, and
378 MUSCLES AND FASCIA.
Serratus magniis. By its dee^D surface, with the Splenius, upper part of tlie
Erector spin^e, Intercostal muscles and ribs.
The Serratus Posticus Inferior is situated at the junction of the dorsal and
lumbar regions: it is of an irregularly quadrilateral form, broader than the
preceding, and separated from it bj a considerable interval. It arises by a thin
aponeurosis from the spinous processes of the last two dorsal and two or three
upper lumbar vertebrae, and from the interspinous ligaments. Passing obliquely
upwards and outwards, it becomes fleshy, and divides into four flat digitations,
which are inserted into the lower borders of the four lower ribs, a little beyond
their angles.
Relations. By its superficial surface, with the Latissimus dorsi, with the
aponeurosis of which its own aponeurotic origin is inseparably blended. By its
deep surface, with the lumbar fascia, the Erector spinte, ribs and Intercostal
muscles. Its upper margin is continuous with the vertebral aponeurosis.
The Vertebral Ap)oneurosis is a thin aponeurotic lamina, extending along the
whole length of the back part of the thoracic region, serving to bind down the
Erector spinae, and separating it from those muscles which connect the spine to
the upper extremity. It consists of longitudinal and transverse fibres blended
together, forming a ,thin lamella, which is attached in the median line to the
spinous processes of the dorsal vertebree; externally, to the angles of the ribs;
and below, to the upper border of the Inferior serratus and tendon of the
Latissimus dorsi ; above, it passes beneath the Splenius, and blends with the
deep fascia of the neck.
Now detacli tlie Rerratus posticus superior from its origin, and turn it outwards, when the
Splenius muscle will be brought into view.
The Sp)lenius is situated at the back of the neck and upper part of the dorsal •
region. At its origin, it is a single muscle, narrow, and pointed in form ; but
it soon becomes broader, and divides into two portions, which have separate
insertions. It arises, by tendinous fibres, from the lower half of the ligamentum
nuchc^, from the spinous processes of the last cervical and of the six upper
dorsal vertebrse, and from the supraspinous ligament. From this origin, the
fleshy fibres proceed obliquely upwards and outwards, forming a broad flat
muscle, which divides as it ascends into two portions, the Splenius capitis and
Splenius colli.
The Splenius Capitis is inserted into the mastoid process of the temporal bone,
and into the rough surface on the occipital bone beneath the superior curved
line.
The Spjlenius Colli is inserted, by tendinous fasciculi, into the posterior
tubercles of the transverse processes of the three or four upper cervical verte-
brae.
The Splenius is sej)arated from its fellow of the opposite side b}^ a triangular
interval, in which is seen the Complexus.
Relations. By its superficial surface, with the Trapezius, from which it is
separated below by the Ehomboidei and the Serratus posticus superior. It is
covered at its insertion by the Sterno-mastoid. By its deej^ surface, with the
Spinalis doi'si, Longissimus dorsi, Semispinalis colli, Complexus, Trachelo-
mastoid, and Transvcrsalis colli.
Nerves. The Splenius and Superior serratus arc supplied from the external
posterior branches of the cervical nerves ; the Inferior serratus from the exter-
nal branches of the dorsal nerves.
Actions. Tlic Serrati arc respiratory muscles acting in antagonism to each
other. The Serratus posticus superior elevates the ribs; it is, therefore, an
inspiratory muscle; while the Sernitns inferior draws the lower ribs downwards,
and is a muscle of expiration. ^^Iiis muselc is also ])rolxibly a tensor of the
vertebral aponeurosis. Tlic Splcnii muscles of the two sides, acting together,
draAV the bead directly backwards, assisting the Trapezius and Complexus ;
OF THE BACK. 379
acting separately, they draw the head to one or the other side, and shghtly
rotate it, turning the face to the same side. They also assist in supporting the
head in the erect position.
FouETH Layer.
Sacral and Lunibar Regions. Cervical Region.
Erector Spinje. Cervicalis Ascendens.
Dorsal Region. Transversalis Colli.
Sacro-lumbalis. Trachelo-mastoid.
Musculus Accessorius ad Sacro- lumbal em. Complexus.
Longissimus Dorsi. Biventer Cervicis.
Spinalis Dorsi. Spinalis Colli,
Dissection. To expose the muscles of the fourth layer, remove entirely the Serrati and verte-
bral aponeurosis. Then detach the Splenius by separating its attachment to the spinous
processes, and reflecting it outwards.
The Erector Spinse (Fig. 258), and its prolongations in the dorsal and cervical
regions, fill up the vertebral groove on each side of , 'the spine. It is covered in
the lumbar region by the lumbar aponeurosis; In the dorsal region by the
Serrati muscles and the vertebral aponeurosis ; and in the cervical region by a
layer of cervical fascia continued beneath the Trapeziu-S. This large muscular
and tendinous mass varies in size and structure at different parts of the spine.
In the sacral region, the Erector spinse is narrow and pointed, and its origin
chiefly tendinous in structure. In the lumbar region, the muscle becomes
enlarged, and forms a large fleshy mass. In the dorsal region, it subdivides into
two parts, which gradually diminish in size as they ascend to be inserted into
the vertebrae and ribs, and are gradually lost in the cervical region, where a
number of special muscles are superadded ; which are continued upwards to the
head, and support it upon the spine.
The Erector spinae arises from the sacro-iliac groove, and from the anterior
surface of a very broad and thick tendon, which is attached, internally, to the
spines of the sacrum, to the spinous processes of the lumbar and three lower
dorsal vertebrse, and the supraspinous ligament ; externally, to the back part
of the inner lip of the crest of the ilium, and to the series of eminences on the
posterior part of the sacrum, which represent the transverse processes, where it
blends with the great sacro-sciatic ligament. The muscular fibres form a single
large fleshy mass, bounded in front by the transverse processes of the lumbar
vertebrae, and by the middle lamella of the aponeurosis of origin of the Trans-
versalis muscle. Opposite the last rib, it divides into two parts, the Sacro-
lumbalis, and the Lono-issimus dorsi.
The Sacro-lwnhalis (Ilio-costalis), the external and smaller portion of the
Erector spin^, is inserted, by six or seven flattened tendons, into the angles of
the six lower ribs. If this muscle "is reflected outwards, it will be seen to be
reinforced by a series of muscular slips, which arise from the angles of the ribs ;
by means of these the Sacro-lumbalis is continued upwards to the upper ribs,
and the cervical portion of the spine. The accessory portions form two addi-
tional muscles, the Musculus accessorius and the Cervicalis ascendens.
The Musculus accessorius ad Sacro-lumhalein arises, by separate flattened
tendons, from the angles of the six lower ribs ; these become muscular, and are
finally inserted, by separate tendons, into the angles of the six upper ribs.
The Cervicalis ascendens^ is the continuation of the Accessorius upwards into
the neck : it is situated on the inner side of the tendons of the Accessorius,
arising from the angles of the four or five upper ribs, and is inserted by a series
' This muscle is sometimes called " Cervicalis descendens." The student should remember that
these long muscles take their fixed point from above or from below, according to circumstances.
380
MUSCLES AND FASCIiE,
Fig. 258. — Muscles of the Back. Deep Layers.
MULTiriaUS SPlN/C
ifDoro^l \
f'LMJJ^" V'-
^SacjalY-\
OF THE BACK. 381
of slender tendons into tlie posterior tubercles of the transverse processes of the
fourth, fifth, and sixth cervical vertebrae.
The Longissimus Dors% the inner and larger portion of the Erector spin^e,
arises, with the Sacro-lumbalis, from the common origin above described. In
the lumbar region, where it is as yet blended with the Sacro-lumbalis, some of
the fibres are attached to the whole length of the posterior surface of the trans-
verse processes of the lumbar vertebrae, to the tubercles at the back of the
articular processes, and to the middle layer of the aponeurosis of origin of the
Transversalis abdominis muscle. In the dorsal region, the Longissimus dorsi
is inserted, by long thin tendons, into the tips of the transverse processes of all
the dorsal vertebra, and into from seven to eleven ribs between their tubercles
and angles. This muscle is continued upwards, to the cranium and cervical
portion of the spine, by means of two additional muscles, the Transversalis colli
and Trachelo-mastoid.
The Transversalis Colli^ placed on the inner side of the Longissimus dorsi,
arises by long thin tendons from the summits of the transverse processes of the
third, fourth, fifth, and sixth dorsal vertebra, and is inserted by similar tendons
into the posterior tubercles of the transverse processes of the five lower cervical.
The Trachelo-mastoid lies on the inner side of the preceding, between it and
the Complexus muscle. It arises by four tendons, from the transverse processes
of the third, fourth, fifth, and sixth dorsal vertebrse and by additional separate
tendons from the articular processes of the three or four lower cervical. The
fibres form a small muscle, which ascends to be inserted into the posterior margin
of the mastoid process, beneath the Splenius and Sterno-mastoid muscles. This
small muscle is almost always crossed by a tendinous intersection near its inser-
tion into the mastoid process.
The Spinalis Dorsi connects the spinous processes of the upper lumbar and
the dorsal vertebras together by a- series of muscular and tendinous slips, which
are intimately blended with the Longissimus dorsi. It is situated at the inner
side of the Longissimus dorsi, arising, by three or four tendons, from the spinous
processes of the first two lumbar and the last two dorsal vertebrae : these uniting,
form a small muscle, which is inserted, by separate tendons, into the spinous
processes of the dorsal vertebree, the number varying from four to eight. It is
intimately united with the Semispinalis dorsi, which lies beneath it.
The Spinalis Colli is a small muscle, connecting together the spinous j^rocesses
of the cervical vertebrse, and analogous to the Spinalis dorsi in the dorsal region.
It varies considerably in its size, and in its extent of attachment to the vertebra?,
not only in different bodies, but on the two sides of the same body. It usually
arises by fleshy or tendinous slips, varying from two to four in number, from the
spinous processes of the fifth and sixth cervical vertebree, and occasionally from
the first and second dorsal, and is inserted into the spinous process of the axis,
and occasionally into the spinous process of the two vertebrae below it. This
muscle was found absent in five cases out of twenty-four.
The Complexus is a broad thick muscle, situated at the upper and back part
of the neck, beneath the Splenius, and internal to the Transversalis colli and
Trachelo-mastoid. It arises, by a series of tendons, about seven in number,
from^ the tips of the transverse processes of the upper three dorsal and seventh
cervical, and from the articular processes of the three cervical above this. The
tendons uniting form a broad muscle, which passes obliquely upwards and
inwards, and is inserted into the innermost depression between the two curved
lines of the occipital bone. This muscle, about its middle, is traversed by a
transverse tendinous intersection.
l^h.Q Biventer Gervicis is a small fasciculus, situated on the inner side of the
preceding, and in the majority of cases blended with it ; it has received its name
from having a tendon intervening between two fleshy bellies. It is sometimes
described as a separate muscle, arising, by from two to four tendinous slips, from
the transverse processes of as many of the upper dorsal vertebras, and inserted,
382 MUSCLES AND FASCIA.
on the inner side of tlie Complexiis, into tlie superior curved line of tlie occipital
bone.
Relations. The muscles of the fourth layer are bound down to the vertebrae
and ribs in the dorsal and lumbar regions by the lumbar fascia and vertebral
aponeurosis. The inner part covers the muscles of the fifth layer. In the neck
they are in relation, by their superficial surface^ with the Trapezius and Splenius ;
by their deep surface^ with the Semispinalis dorsi, Semispinalis colli, the Recti and
Obliqui. The Biventer cervicis is separated from its fellow of the opposite side
by the ligamentum nuchae, and the Oomplexus from the Semispinalis colli by
the profunda cervicis artery, the princeps cervicis artery, and branches of the
posterior cervical plexus of nerves.
Nerves. The Erector spinse and its subdivisions in the dorsal region are sup-
plied by the external posterior branches of the lumbar and dorsal nerves ; the
Cervicalis ascendens, Transversalis colli, Trachelo-mastoid, and Spinalis cervicis,
by the external posterior branches of the cervical nerves ; the Complexus by the
internal posterior branches of the cervical nerves, the suboccipital, and great
occipital.
Fifth Layer.
Semispinalis Dorsi. Extensor Coccygis,
Semispinalis Colli. Intertransversales.
Multifidus Spinse. Rectus Capitis Posticus Major.
Eotatores Spinse. Rectus Capitis Posticus Minor.
Supraspinales. Obliquus Capitis Superior.
Interspinales. Obliquus Capitis Inferior.
Dissection. Remove the muscles of the preceding layer by dividing and turning aside the
Complexus; then detaching the Spinalis and Longissimus dorsi from their attachments, dividing
the Erector Spinas at its connection below to the sacral and Inmbar spines, and turning it out-
wards. The muscles filling up the interval between the spinous and transverse processes are then
exposed.
\
The Semispinales muscles (Fig. 258) connect the transverse and articular pro-
cesses to the spinous processes of the vertebrte, extending from the lower part
of the dorsal region to the upper part of the cervical.
The Semispinalis Dorsi consists of thin, narrow, fleshy fasciculi, interposed
between tendons of considerable length. It arises by a series of small tendons
from the transverse processes of the lower dorsal vertebrae, from the tenth or
eleventh to the fifth or sixth ; and is inserted, by five or six tendons, into the
spinous processes of the upper four dorsal and lower two cervical vertebrae.
The Semispinalis Colli, thicker than the preceding, arises by a series of tendi-
nous and fleshy points from the transverse processes of the upper four dorsal
vertebrae and from the articular processes of the lower four cervical vertebrae ;
and is inserted into the spinous processes of four cervical vertebrae, from the
axis to the fifth cervical. The fasciculus connected with the axis is the largest,
and chiefly muscular in structure.
Relations. By their sriperficial surf ace, ir ova below upwards, with the Longis-
simus dorsi, Sjnnalis dorsi, Splenius, Complexus, the profunda cervicis artery,
the princeps cervicis artery, and the posterior cervical plexus of nerves. By
their dfpp surface, with the Multifidus spime.
Tlic Multifidus Sfdnve consists of a number of fleshy and tendinous fjisciculi,
wliicli fill up the groove on cither side of the s])inous processes of the vertebrae,
from the sacrum to the axis. In the sacral region, these fasciculi airise from the
back of the sacrum, as low as the fourth sacral foramen, and from the aponeurosis
of origin of the Erector spinre; in iho ib'ac region, from the inner surface of the
posterior superior spine of the iliiini, ami poslcrior sacro-iliac ligaments; in the
lumbar and cervical regions, from \\\ii articular processes; and in the dorsal region,
from the transverse processes. Each fasciculus, ascending oblirjuely upwards
OF THE BACK. 383
and inwards, is inserted into tlie lamina and wliole lengtli of tlie spinous process
of one of the vertebrae above. These fascicuh vary in length: the most super-
ficial, the longest, pass from one vertebra to the third or fourth above ; those next
in order pass from one vertebra to the second or third above ; whilst the deepest
connect two contiguous vertebrae.
Belations. By its superficial surface^ with the Longissimus dorsi, Spinalis dorsi,
Semispinalis dorsi, and Semispinalis colli. By its deep surface, with the laminae
and spinous processes of the vertebrae, and with the rotatores spina3 in the dorsal
region.
The Rotatores Spinse are found only in the dorsal region of the spine, beneath
the Multifidus spinge ; they are eleven in number on each side. Each muscle
is small and somewhat quadrilateral in form ; it arises from the upper and back
part of the transverse process, and is inserted into the lower border and outer
surface of the lamina of the vertebra above, the fibres extending as far inwards
as the root of the spinous process. The first is found between the first and second
dorsal ; the last, between the eleventh and twelfth. Sometimes the number of
these muscles is diminished by the absence of one or more from the upper or
lower end.
The Supraspinales consist of a series of fleshy bands, which lie on the spinous
processes in the cervical region of the spine.
The Inter spinales are short muscular fasciculi, placed in pairs between the
spinous processes of the contiguous vertebrae. In the cervical region they are
most distinct, and consist of six pairs, the first being situated between the axis
and third vertebra, and the last between the last cervical and the first dorsal.
They are small narrow bundles, attached, above and below, to the apices of the
spinous processes. In the dorsal region, they are found between the first and
second vertebrae, and occasionally between the second and third; and below,
between the eleventh and twelfth. In the lumbar region, there are four pairs of
these muscles in the intervals between the five lumbar vertebras. There is also
occasionally one in the interspinous space, betA\^een the last dorsal and first
lumbar, and betvAcen the fifth lumbar and the sacrum.
The Extensor Coccygis is a slender muscular fasciculus, occasionally present,
which extends over the lower part of the posterior surface of the sacrum and
coccyx. It arises by tendinous fibres from the last bone of the sacrum, or first
piece of the coccyx, and passes downwards to be inserted into the lower part of
the coccyx. It is a rudiment of the Extensor muscle of the caudal vertebrae
which exists in some animals.
The Intertransversales are small muscles placed between the transverse pro-
cesses of the vertebrae. In the cervical region, they are most developed, consisting
of two rounded muscular and tendinous fasciculi, which pass between the anterior
and posterior tubercles of the transverse processes of two contiguous vertebrae,
separated from one another by the anterior branch of a cervical nerve, which
lies in the groove between them, and by the vertebral artery and vein. In this
region there are seven pairs of these muscles, the first being between the atlas
and axis, and the last between the seventh cervical and first dorsal vertebrae. In
the dorsal region, they are at least developed, consisting chiefly of rounded tendi-
nous cords in the intertransverse spaces of the upper dorsal vertebrae ; but
between the transverse processes of the lower three dorsal vertebrae, and the first
lumbar, they are muscular in structure. In the luinhar region, they are four in
number, and consist of a single muscular layer, which occupies the entire inter-
space between the transverse processes of the lower lumbar vertebra, whilst those
between the transverse processes of the u]3per lumbar are not attached to more
than the breadth of the process.
The Rectus Capitis Posticus Major arises by a pointed tendinous origin from
the spinous process of the axis, and, becoming broader as it ascends, is inserted
into the inferior curved line of its occipital bone and the surface of bone imme-
diately below it. As the muscles of the two sides ascend upwards and outwards,
384 MUSCLES AND FASCIA.
thej leave between tliem a triangular space, in wliicli are seen the Eecti capitis
postici minores muscles.
Relations. By its superficial surface.^ withtlie Complexus, and, at its insertion,
witli the Superior oblique. Bj its deep surface^ with the posterior arch of the
atlas, the posterior occipito-atloid ligament, and part of the occipital bone.
The Rectus Capitis Posticus Minor^ the smallest of the four muscles in this
region, is of a triangular shape ; it arises by a narrow pointed tendon from the
tubercle on the posterior arch of the atlas, and, becoming broader as it ascends,
is inserted into the rough surface beneath the inferior curved line, nearly as far
as the foramen magnum, nearer to the middle line than the preceding.
Relations. 'Bj it^ superficial surf ace -v^ith the Complexus. By its deep) surface.,
with the posterior occipito-atloid ligament.
The Ohliquus CcLpitis Inferior., the larger of the two oblique muscles, arises
from the apex of the spinous process of the axis, and passes almost horizontally
outwards, to be inserted into the apex of the transverse process of the atlas.
Relations. By its superficial surface with the Complexus, and with the posterior
branch of the second cervical nerve which crosses it. By its deep surface., with
the vertebral artery, and posterior atlo-axoid ligament.
The Ohliquus Capitis Superior., narrow below, wide and expanded above, arises
by tendinous fibres from the upper part of the transverse process of the atlas,
joining with the insertion of the preceding, and, passing obliquely upwards and
inwards, is inserted into the occipital bone, between the two curved lines, external
to the Complexus. Between the two Oblique muscles and the Eectus posticus
major a triangular interval exists, in which are seen the vertebral artery, and the
posterior branch of the suboccipital nerve.
Relations. By its superficial surface., with the Complexus and Trachelo-mastoid.
By its deep surface., with the posterior occipito-atloid ligament.
Nerves. The Semispinalis clorsi and Eotatores spinas are supplied by the
internal posterior branches of the dorsal nerves ; the Semispinalis colli, Supra-
spinales, and Interspinales, by the internal posterior branches of the cervical
nerves; the Intertransversales, by the internal posterior branches of the cervical,
dorsal, and lumbar nerves ; the Mu.ltifidus spinse, by the same, with the addition
of the internal |)osterior branches of the sacral nerves. The Recti and Obliqui
muscles are all supplied by the suboccipital and great occipital nerves.
Actions. The Erector spinas, comprising the Sacro-lumbalis, with its accessory
muscles, the Longissimus dorsi and Spinalis dorsi, serves, as its name implies,
to maintain the spine in the erect posture ; it also serves to bend the trunk
backwards when it is required to counterbalance the influence of any weight at
the front of the body, as, for instance, when a heavy weight is suspended from
the neck, or when there is any great abdominal development, as in pregnancy
or dropsy ; the peculiar gait under such circumstances depends upon the spine
being drawn backwards, by the counterbalancing action of the Erector spinas
muscles. The muscles which form the continuation of the Erector spinte up-
wards steady the head and neck, and fix them in the upright position. If the
Sacro-lumbalis and Longissimus dorsi of one side act, they serve to draw down
the chest and spine to the corresponding side. The Cervicalis ascendens, taking
its fixed point from the cervical vertebrae, elevates those ribs to which it is
attached. The Multifidus spinas acts successively upon the diflerent parts of
the sf)inc; thus, the sacrum furnishes a fixed point from which the fasciculi of
this rriiisclc act upon tlie himbar region; these then become the fixed points for
ihc fasciculi moving the dorsal region, and so on throughout the entire length
of the spine; it is by the successive contraction and rehixation of the separate
fhsciculi of this and other muscles, that the spine preserves the erect posture
without the fatigue that would necessarily have been produced, had this position
been maintained by the action of a single muscle. The Multifidus spin^e, besides
])rescrving the erect position of the spine, serves to rotate it, so that the front
of the trunk is turned to the side opposite to that from which the muscle acts,
OF THE ABDOMEN.
385
tMs muscle "being assisted in its action by the Obliqnns externus abdominis.
The Complexi, the analogues of the Multifidus spinas in the neck, draw the head
directly backward ; if one muscle acts, it draws the head to one side, and rotates
it so that the face is turned to the opposite side. The Eectus capitis posticus
minor and the Obliquus superior draw the head backwards ; and the latter, from
the obliquity in the direction of its fibres, may turn the face to the opposite side.
The Eectus capitis posticus major and the Obliquus inferior rotate the atlas,
and, with it, the cranium round the odontoid process, and turn the face to the
same side.
Muscles of the Abdomen.
The Muscles in this region are, the
Obliquus Externus.
Obliquus Internus.
Transversalis.
Eectus.
Pyramidalis.
Quadratus Lumborum.
Fiff. 259. — Dissection of Abdomen.
Dissection (Fig. 259). To dissect the abdominal muscles, make a vertical incision from the
ensiform cartilage to the pubes, a second incision from the umbilicus obliquely upwards and out-
wards to the outer surface of the chest, as high as the lower border of the fifth or sixth rib, and
a third, commencing midway between the umbilicus and pubes, transversely outwards to the ante-
rior superior iliac spine, and along the crest of the ilium as far as its posterior third. Then
reflect the three flaps included between these incisions from within outwards, in the line of direc-
tion of the muscular fibres. If necessary, the abdominal muscles may be made tense by inflating
the peritoneal cavity through the umbilicus.
The External or Descending Oblique Muscle (Fig. 260) is situated on the side
and fore part of the abdomen ; being the largest and the most superficial of the
three flat muscles in this region. It is broad, thin, and irregularly quadrilateral,
its muscular portion occupying the side, its aponeurosis the anterior wall of the
abdomen. It arises, by eight fleshy digitations, from the external surface and
lower borders of the eight inferior ribs ; these digitations are arranged in an ob-
lique line running downwards and backwards ; the upper ones being attached
close to the cartilages of the corresponding ribs ;
the lowest, to the apex of the cartilage of the
last rib; the intermediate ones, to the ribs at
some distance from their cartilages. The five
superior serrations increase in size from above
downwards, and are received between corre-
sponding processes of the Serratus magnus ; the
three lower ones diminish in size from above
downwards, receiving between them correspond-
ing processes from the Latissimus dorsi. From
these attachments, the fleshy fibres proceed in
various directions. Those from the lowest ribs
pass nearly vertically downwards, to be inserted
into the anterior half of the outer lip of the
crest of the ilium ; the middle and upper fibres,
directed downwards and forwards, terminate in
tendinous fibres, which spread out into a broad
aponeurosis. This aponeurosis, joined with that
of the opposite muscle along the median line,
covers the whole of the front of the abdomen ;
above, it is connected with the lower border of
the Pectoralis major ; below, its fibres are
closely aggregated together, and extend obliquely
across from the anterior superior spine of the
ilium to the spine of the os pubis and the linea
ilio-pectinea. In the median line, it interlaces with the aponeurosis of the oppo-
site muscle, forming the linea alba, and extends from the ensiform cartilage to
the symphysis pubis.
25
386
MUSCLES AND FASCIA.
Tliat portion of tlie aponeurosis wliich extends between tlie anterior superior
spine of tlie ilium and the spine of tlie os pubis, is a broad band, folded inwards,
and continuous below witli the fascia lata ; it is called Poupart's ligament. The
portion which is reflected from. Poupart's ligament into the pectineal line is
called Oimhernafs liyament} From the point of attachment of the latter to the
pectineal line, a few fibres pass upwards and inwards, behind the inner pillar
of the ring, to the linea alba. They diverge as they ascend, and form a thin,
triangular, fibrous band, which is called the triangular ligament.
Fig. 260.— The External Oblique Muscle.
Evt.Aldomlval Eruf
Ci'iiibvinat's Li'jh—
In the aponeurosis of the External (>bli(|no, immediately above the crest of
the OS pubis, is a triangular opening, tlie external ahdominal ring^ formed by a
separation of the fibres of the aponeurosis in this situation : it serves for the
transmission r)f tlio, sporiiifitic cord in the male, and tlie refund ligament in the
female. Tliis opening is directed ()1)lir|u(!lv n]nvards and outAvards, and corre-
' All Ihfsc; parts will lie found nioix' jjarticularly described liercuflcr, with the Surgical Anatomy
of Hernia.
OF THE ABDOMEN. 387
spends witli the conrse of tTie fibres of tlie aponenrosis. It is bounded, below,
by the crest of the os pubis ; above, by some curved fibres, which pass across
tlie aponeurosis at the upper angle of the ring, so as to increase its strength ;
and, on either side, by the margins of the aponeurosis, which are called the
pillars of the ring. Of these, the external, which is, at the same time, inferior,
from the obliquity of its direction, is inserted into the spine of the os pubis.
The internal, or superior pillar, is attached to the front of the pubes and
symphysis pubis, and interlaces with the corresponding fibres of the opposite
muscle, the fibres of the right muscle being superficial. To the margins of the
pillars of the external abdominal ring is attached an exceedingly thin and
delicate fascia, which is prolonged down over the outer surface of the cord and
testis. This has received the name of intercolumnar fascia^ from its attachment
to the pillars of the ring. It is also called the external spermatic fascia^ from
being the most external of the fascige which cover the spermatic cord.
Relations. By its external or superficial surface^ with the superficial fascia,
superficial epigastric and circumflex iliac vessels, and some cutaneous nerves.
By its internal or deep surface.^ with the Internal oblique, the lower part of the
eight inferior ribs, and Intercostal muscles, cremaster, the spermatic cord in the
male, and round ligament in the female. Its posterior border is occasionally
overlapped by the Latissimus dorsi ; sometimes an interval exists between the
two muscles, in which is seen a portion of the Internal oblique.
Dissection. Detach the External oblique by dividing it across, just in front of its attachment
to the ribs, as far as its posterior border, and separating it below from the crest of the ilium as
far as the spine; then separate the muscle carefully from the Internal oblique, which lies beneath,
and turn it towards the opposite side.
The Internal or Ascending Oblique Muscle (Fig. 261), thinner and smaller than
the preceding, beneath which it lies, is of an irregularly quadrilateral form, and
situated at the side and fore part of the abdomen. It arises, by fleshy fibres,
from the outer half of Poupart's ligament, being attached to the groove on its
upper surface ; from the anterior two-thirds of the middle lip of the crest of the
ilium, and from the lumbar fascia. From this origin, the fibres diverge : those
from Poupart's ligament, few in number and paler in color than the rest, arch
downwards and inwards across the spermatic cord, to be inserted, conjointly with
those of the Transversalis, into the crest of the os pubis and pectineal line, to the
extent of half an inch, forming what is known as the conjoined tendon of the
Internal oblique and Transversalis ; those from the anterior superior iliac spine
are horizontal in their direction; whilst those which arise from the fore part of
the crest of the ilium pass obliquely upwards and inwards, and terminate in an
aponeurosis, which is continued forwards to the linea alba ; the most posterior
fibres ascend almost vertically upwards, to be inserted into the lower borders of
the cartilages of the four lower ribs, being continuous with the Internal Inter-
costal muscles.
The conjoined tendon of the Internal oblique and Transversalis is inserted
into the crest of the os pubis and pectineal line, immediately behind the external
abdominal ring, serving to protect what would otherwise be a weak point in the
abdomen. Sometimes this tendon is sufl&cient to resist the pressure from within,
and is carried forward in front of the protrusion through the external ring, form-
ing one of the coverings of direct inguinal hernia.
The aponeurosis of the Internal oblique is continued forward to the middle
line of the abdomen, where it joins with the aponeurosis of the opposite muscle
at the linea alba, and extends from the margin of the thorax to the pubes. At
the outer margin of the Rectus muscles, this aponeurosis, for the upper three-
fourths of its extent, divides into two lamellge, which pass, one in front and the
other behind the muscle, inclosing it in a kind of sheath, and reuniting on its
inner border at the linea alba ; the anterior layer is blended with the aponeu-
rosis of the External oblique muscle ; the posterior layer with that of the Trans-
versalis. Along the lower fourth, the aponeurosis passes altogether in front of
the Pectus without any separation.
388
MUSCLES AND FASCIA.
Relations. Bj its external surface^ with the External oblique, Latissimus dorsi,
spermatic cord, and external ring. By its internal surface^ with the Transversalis
muscle, fascia transversalis, internal ring, and spermatic cord. Its lower border
forms the upper boundary of the spermatic canal.
Fig. 261.— The Internal Oblique Muscle.
Corjoined Tene/on—.jr
CREMASTER
Difisection. Detach the Internal ohliqne in order to expose the Transversalis beneath. This
may be effected by dividin<r the muscle, above, at its attachment to the ribs; below, at its con-
nection with Poui)an's li<iament and the crest of the ilium ; and behind, by a vertical incision
extending from tlie last rib to the crest of the ilium. The muscle should previously be made
tense by drawing upon it with the fingers of the left hand, aud if its division is carefully effected,
the cellular interval between it and the 'IVansversalis, as well as the direction of the fibres of the
latter muscle, will afford a clear guide to their separation ; along the crest of the ilium the cir-
cumflex iliac vessels are interposed between them, and form an important guide in separating
them. The muscle should tlien be thrown forwards towards the linea alba.
Tlic Tramversalis mvsch (Fig. 262), so called (roin lhe dii'cclion of its fibres,
is the most internal flat muscle of tlic abdomen, being ])laced immediately
beneath the Jnternal oblique. It arises by fleshy fibres from the outer third of
Poupart's ligament, from the inner lip of the crest of the ilium, its anterior
three- fourths, from the inner surface of the cartilages of the six lower ribs,
interdigitating witli the Dia])liragm, and by a broad aponeurosis from the
Bpinous and transverse pro(;cssess of the lumbar vertebrae. The lower fibres
curve downwards, finr] arc inscrterl, together with those of the Internal oblique,
into the crest of the os pubis iind |icc,tincal line, forming Avhat was described
above as the conjoined tendon of these muscles. Throughout the rest of its
OF THE ABDOMEN.
389
extent the fibres pass horizontally inwards, and near the outer margin of the
Rectus, terminate in an aponeurosis, which is inserted into the linea alba; its
upper three-fourths passing behind the Rectus muscle, blending with the poste-
rior lamella of the Internal oblique; its lower fourth passing in front of the
Rectus.
Fig. 262.— The Traiisversalis, Rectus, and Fyramidalis Muscles.
Z m e a a 1 ha
Relations. By its external surface^ with the Internal oblique, the inner surface
of the lower ribs, and Internal intercostal muscles. Its inner surface is lined by
the fascia transversalis, which separates it from the peritoneum. Its lower
border forms the upper boundary of the spermatic canal.
Lumhar Fascia (Fig. 263). The vertebral aponeurosis of the Transversalis
divides into three layers : an anterior, very thin, which is attached to the front
part of the transverse processes of the lumbar vertebras, and, above, to the
lower margin of the last rib, where it forms the ligamentum arcuatum exter-
390 MUSCLES AND FASCIA.
num: a middle layer, much stronger, wliicli is attacTied to tlie apices of tlie
transverse processes ; and a posterior layer, attached to the apices of the spinous
processes. Between the anterior and middle layers is situated the Quadratus
lumborum ; between the middle and posterior, the Erector spinas. The poste-
rior lamella of this aponeurosis receives the attachment of the Internal oblique;
it is also blended with the aponeurosis of the Serratus posticus inferior and with
that of the Latissimus dorsi, forming the lumbar fascia.
Fig. 263.- A Transverse Section of the Abdomen in the Lumbar Kegion.
Dt!Jsection. To expose the Rectus muscle, open its sheath by a vertical incision extending
from the margin of the thorax to the pubes, and then reflect the two portions from the surface
of the muscle, which is easily done, excepting at the linse transversse, where so close an adhesion
exists, that the greatest care is requisite in separating them. Now raise the outer edge of the
muscle, in order to examine the posterior layer of the sheath. By dividing the muscle in the
centre, and turning its lower part downwards, the point where the posterior wall of the sheath
terminates in a thin curved margin will be seen.
The Rectus Abdominis is a long flat muscle, which extends along the whole
length of the front of the abdomen, being separated from its fellow of the
opposite side by the linea alba. It is much broader above than below, and
arises by two tendons, the external or larger being attached to the crest of the
OS pubis; the internal, smaller portion, interlacing with its fellow of the opposite
side, and being connected with the ligaments covering the symphysis pubis.
The fibres ascend vertically, and the muscle, becoming broader and thinner at
its upper part, is inserted by three portions of imequal size into the cartilages
of the fifth, sixth, and seventh ribs. Some 'fibres are occasionally connected
with the costo-xiphoid ligaments, and side of the ensiform cartilage.
Tlie Kectus muscle is traversed by a series of tendinous intersections, which
vary from two to five in number, and have received the name Lineas transversge.
One of these is usually situated opposite the umbilicus, and two above that
point ; of the latter, one corresponds to the ensiform cartilage, and the other, to
the interval between the ensiform cartilage and the umbilicus; there is occa-
sionally one below the umbilicus. These intersections pass transversely or
obliquely across the muscle in a zigzag course; they rarely extend completely
through its substance, sometimes pass only halfway across it, and arc intimately
adherent to the sheath in which the muscle is inclosed.
The Kcclns is inclosed in a sheath (Fig. 263) formed by the n]-)oncurosis of the
m)lifjuc and Tnmsversjilis muscles, which are arranged in the following manner.
When the aponeurosis of the Inlernal oblique arrives at the outer margin of the
Kectus, it divides into two lamcllie, one of which passe« in front of the Ecctus,
OF THE ABDOMEN. 391
blending witb. tlie aponeurosis of tlie External oblique ; the other, behind it,
blending with the aponeurosis of the Transversalis : and these, joining again at
its inner border, are inserted into the linea alba. This arrangement of the
fasciae exists along the upper three-fourths of the muscle : at the commencement
of the lower fourth, the posterior wall of the sheath terminates in a thin curved
margin, or falciform edge^ the concavity of which looks downwards towards the
pubes ; the aponeuroses of all three muscles passing in front of the Eectus with-
out any separation. The Rectus muscle, in the situation where its sheath is
deficient, is separated from the peritoneum by the transversalis fascia.
The Pyi-amidalis is a small muscle, triangular in shape, placed at the lower
part of the abdomen, in front of the Rectus, and contained in the same sheath
with that muscle. It arises by tendinous fibres from the front of the os pubis
and the anterior pubic ligament : the fleshy portion of the muscle passes upwards,
diminishing in size as it ascends, and terminates by a pointed extremity, which
is inserted into the linea alba, midway between the iimbilicus and the os pubis.
This muscle is sometimes found wanting on one or both sides ; the lower end of
the Rectus then becomes proportionately increased in size. Occasionally, it has
been found double on one side, or the muscles of the two sides are of unequal
size. Sometimes its length exceeds what is stated above.
The Quadratus Lumhorum (Fig. 258, p. 380) is situated in the lumbar region ;
it is irregularly quadrilateral in shaj^e, broader below than above, and consists
of two portions. One portion arises by aponeurotic fibres from the ilio-lumbar
ligament, and the adjacent portion of the crest of the ilium for about two inches,
and is inserted into the lower border of the last rib, about half its length, and
by four small tendons, into the apices of the transverse processes of the third,
fourth, and fifth lumbar vertebrae. The other portion of the muscle, situated
in front of the preceding, arises from the upper borders of the transverse pro-
cesses of the third, fourth, and fifth lumbar vertebrae, and is inserted into the
lower margin of the last rib. The Quadratus lumborum is contained in a sheath
formed by the anterior and middle lamellas of the aponeurosis of origin of the
Transversalis.
Relations. Its anterior surface (or rather the fascia which covers its anterior
surface) is in relation with the colon, the kidney, the psoas muscle, and the dia-
phragm. Its posterior sheath separates the Quadratus in front from the Erector
spinee behind, the external edge of the Quadratus, however, overlapping the
Erector spinte to a slight extent.
Nerves. The abdominal muscles are supplied by the lower intercostal, ilio-
hypogastric, and ilio-inguinal nerves. The Quadratus lumborum receives fila-
ments from the anterior branches of the lumbar nerves.
In the description of the abdominal muscles, mention has frequently been
made of the linea alba, linese semilunares and linea transversee ; when the dis-
section of the muscles is completed, these structures should be examined.
The linea alba is a tendinous raph^ or cord seen along the middle line of the
abdomen, extending from the ensiform cartilage to the pubes. It is placed
between the inner borders of the Recti muscles, and is formed by the blending
of the aponeuroses of the Oblique and Transversalis muscles. It is narrow
below, corresponding to the narrow interval existing between the Recti, but
broader above, as these muscles diverge from one another in their ascent,
becoming of considerable breadth after great distension of the abdomen from
pregnancy or ascites. It presents numerous apertures for the passage of vessels
and nerves ; the largest of these is the umbilicus, which in the foetus transmits
the umbilical vessels, but in the adult is obliterated, the cicatrix being stronger
than the neighboring parts ; hence umbilical hernia occurs in the adult above
the umbilicus, whilst in the foetus it occ^^rs at the umbilicus. The linea alba is
in relation, in front, with the integument, to which it is adherent, especially at
the umbilicus ; behind, it is separated from the peritoneum b}^ the transversalis
fascia ; and below, by the urachus, and the bladder when that organ is distended.
392 MUSCLES AND FASCIA.
Tlie linese semilunares are two curved tendinous lines, placed one on eacli side
of tlie linea alba. Eacli corresponds with, the outer border of the Eectus muscle,
extends from the cartilage of the eighth rib to the pubes, and is formed bj the
aponeurosis of the internal oblique at its point of division to inclose the Eectus,
where it is reinforced in front and behind by the External oblique and Trans-
versalis.
The linese transversse are three or four narrow transverse lines which intersect
the Eectus muscle as already mentioned : they connect the linese semilunares
with the linea alba.
Actions. The abdominal muscles perform a threefold action.
When the pelvis and thorax are fixed, they compress the abdominal viscera,
b}^ constricting the cavity of the abdomen, in which action they are materially
assisted by the descent of the diaphragm. By these means the foetus is expelled
from the uterus, the feces from the rectum, the urine from the bladder, and its
contents from the stomach in vomiting.
If the spine is fixed, these muscles compress the lower part of the thorax,
materially assisting in expiration. If the spine is not fixed, the thorax is bent
directly forward, when the muscles of both sides act, or to either side when
those of the two sides act alternately, rotation of the trunk at the same time
taking place to the opposite side.
If the thorax is fixed, these muscles acting together, draw the pelvis upwards,
as in climbing; or, acting singly, they draw the pelvis upwards, and rotate the
vertebral column to one side or the other. The Eecti muscles, acting from
below, depress the thorax, and consequently flex the vertebral column ; when
acting from above, they flex the pelvis upon the vertebral column. The Pyra-
midales are tensors of the linea alba.
The Quadratus lumborum, by the portion inserted into the last rib, draws
down and fixes that bone, acting thereby as a muscle of forced expiration : by
the portion inserted into the lumbar vertebree, it draws the spine towards the
ilium, and thus inclines the trunk towards its own side : or, if the thorax and
spine be fixed, it may act upon the pelvis — raising it towards its own side when
only one muscle is put in action, and when both muscles act together, either
from below or above, they flex the trunk.
Muscles and Fascia of the Thorax.
The Muscles exclusively connected with the bones in this region are few in
number. They are the
Intercostales Externi. Infracostales.
Intercostales Interni. Triangularis Sterni.
Levatores Costarnm.
Intercostal Fascise. A thin but firm layer of fascia covers the outer surface of
the External intercostal and the inner surface of the Internal intercostal muscles;
and a third layer, more delicate, is interposed between the two planes of muscular
fibres. These are the intercostal fascias; they are best marked in those situations
where the muscular fibres are deficient, as between the External intercostal
muscles and sternum, in front ; and between the Internal intercostals and spine,
behind.
Tlic TrilcTcostal Jlfvsclrs (Fig. 267) are two thin ])lanos of muscular and tendi-
nous structure, placed one over the other, filling u\) the intercostal spaces, and
being flircct(;d oblifpiely between the margins of tlie adjacent ribs. They have
received tlic namo "external" aiul "inJoi-iiaV I'roiii the position they bear to one
another.
The External Intercostals arc eleven in number on each side, being attached
to the adjacent margins of each pair of ril)s, and extending from the tubercles
of the ribs, behind, to the commencement of the cartilages of the ribs, in front,
OF THE THORAX. 393
wliere tliey terminate in a tliin membranous aponeurosis, wliicli is continued for-
wards to the sternum. They arise from the outer lip of the groove on the lower
border of each rib, and are inserted into the upper border of the rib below.
In the two lowest spaces they extend to the end of the ribs. Their fibres are
directed obliquely downwards and forwards, in a similar direction with those
of the External oblique muscle. They are thicker than the Internal intercostals.
delations. By their outer surface^ with the muscles which immediately invest
the chest, viz., the Pectoralis major and minor, Serratus magnus, and Ehom-
boideus major, Serratus posticus superior and inferior. Scalenus posticus, Sacro-
lumbalis, Longissimus dorsi, Cervicalis ascendens, Transversalis colli, Levatores
costarum, and the Obliquus externus abdominis. By their internal surf ace^ with
a thin layer of fascia, which separates them from the intercostal vessels and
nerve, and the Internal intercostal muscles, and, behind, from the pleura.
The Internal Intercostals^ also eleven in number on each side, are placed on
the inner surface of the preceding, commencing anteriorly at the sternum, in
the interspaces between the cartilages of the true ribs, and from the anterior
extremities of the cartilages of the false ribs. They extend backwards as far
as the angles of the ribs ; whence they are continued to the vertebral column
by a thin aponeurosis. They arise from the inner lip of the groove on the lower
border of each rib, as well as from, the corresponding costal cartilage, and are
inserted into the upper border of the rib below. Their fibres are directed ob-
liquely downwards and backwards, decussating with the fibres of the preceding.
Relations. By their external surface, with the External intercostals, and the
intercostal vessels and nerves. By their internal surface, with the Pleura costalis.
Triangularis sterni, and Diaphragm.
The Intercostal muscles consist of muscular and tendinous fibres, the latter
being longer and more numerous than the former ; hence the walls of the inter-
costal spaces possess very considerable strength, to which the crossing of the
muscu-lar fibres materially contributes.
A muscle or muscular slip is occasionally found running more or less vertically upwards over
the anterior parts of the ribs, which has been named " Snpracostal muscle" by Mr. J. Wood ('' Proc.
Royal Soc," June 15, 1865), and " Rectus thoracis" by Prof. Turner (" Journ. of Anat. and Phys.."
ser. 2, No. II., p. 392). The latter writer conjectures that it is homologous with the prolongation
of the Rectus abdominis muscle to the thorax, which is met with in some animals. In a case
figured by Prof. Turner, the muscle arose by two heads, one from the fifth rib (the breadth of
which alone separated it from the Rectus abdominis) and the other from the fourth, and ascended
beneath the Pectoralis major muscle to be inserted into the first rib, close to the tendon of the
Subclavius muscle.
The Infracostales consist of muscular and aponeurotic fasciculi, which vary in
number and length ; they arise from the inner surface of one rib, and are inserted
into the inner surface of the first, second, or third rib below. Their direction
is most usually oblique, like the Internal intercostals. They are most frequent
between the lower ribs.
The Triangularis Sterni is a thin plane of muscular and tendinous fibres,
situated upon the inner wall of the front of the chest. It arises from the lower
part of the side of the sternum, from the inner surface of the ensiform cartilage,
and from the sternal ends of the costal cartilages of the three or four lower true
ribs. Its fibres diverge upwards and outwards, to be inserted by fleshy digita-
tions into the lower border and inner surfaces of the costal cartilages of the
second, third, fourth, and fifth ribs. The lowest fibres of this muscle are hori-
zontal in their direction, and are continuous with those of the Transversalis ;
those which succeed are oblique, whilst the superior fibres are almost vertical.
This muscle varies much in its attachment, not only in different bodies, but on
opposite sides of the same body.
Relations. In front, with the sternum, ensiform cartilage, costal cartilages.
Internal intercostal muscles, and internal mammary vessels. Behind, with the
pleura, pericardium, and anterior mediastinum.
The Levatores Costarum (Fig. 258), twelve in number on each side, are small
394 MUSCLES AND FASCIA.
tendinous and ileslij bundles, wliicli arise from the extremities of tile transverse
processes of the dorsal vertebra?, and passing obliquely downwards and out-
wards, are inserted into the upper rough surface of the rib below them, between
the tubercle and the angle. That for the first rib arises from the transverse
process of the last cervical vertebra, and that for the last from the eleventh
dorsal. The Inferior levatores divide into two fasciculi, one of which is inserted
as above described ; the other fasciculus passes down to the second rib below its
origin ; thus, each of the lower ribs receives fibres from the transverse processes
of two vertebrge.
Nerves. The muscles of this group are supplied by the intercostal nerves.
Actions. The Intercostals are the chief agents in the movement of the ribs in
ordinary respiration. The External intercostals raise the ribs, especially their
fore part, and so increase the capacity of the chest from before backwards ; at
the same time they evert their lower borders, and so enlarge the thoracic
cavity transversely. The Internal intercostals, at the side of the thorax, depress
the ribs, and invert their lower borders, and so diminish the thoracic cavity ;
but at the fore part of the chest these muscles assist the External intercostals in
raising the cartilages.^ The Levatores costarum assist the External intercostals
in raising the ribs. The Triangularis sterni draws down the costal cartilages ;
it is therefore an expiratoiy muscle.
Muscles of Inspiration and Expiration. The muscles which assist the action
of the Diaphragm in inspiration are the Intercostals and the Levatores costarum
as above stated, the Scaleni, the Serratus posticus superior, and to a slight extent
the Subclavius. When the need for more forcible action exists, the shoulders
and the base of the scapula are fixed, and then the powerful muscles of forced
inspiration come into play; the chief of these are the Serratus magnus, Latis-
simus dorsi, and the Pectorales, particularly the Pectoralis minor. The Sterno-
mastoid also, when the head is fixed, assists in forced inspiration, by drawing up
the sternum, and by fixing the clavicle, and thus affording a fixed point for the
action of the muscles of the chest.
The ordinary action of expiration is merely passive, the resilience of the ribs
and the elasticity of the lungs being sufficient to produce it. This causes the
ascent of the abdominal viscera covered by the Diaphragm. Forced expiratory
actions are performed mainly by the flat muscles (Obliqui and Transversalis)
of the abdomen, assisted also by the Eectus. Other muscles of forced expiration
are the Internal intercostals and Triangularis sterni (as above mentioned), the
Serratus posticus inferior, the Quadratus lumborum, and the Sacro-lumbalis.
Diaphragmatic Eegiox,
Diaphragm.
The Diaphragm (5t.a>pay/ia, a partition ivalT) (Fig. 26'l)isathin musculo-fibrous
septum, placed obliquely at the junction of the upper with the middle third of
the trunk, and separating the thorax from the abdomen, forming the floor of the
former cavity and the roof of the latter. It is elliptical, its longest diameter being
from side to side, somewhat fau-sliaped, the broad elliptical portion being hori-
' The viow of iho action of llio IDIorcostal mnsdps privpn in 1lio Icxi is lliat wliicli is liuiulit l)y
Hnlcliinson (" (Jycl. of Aiiat. and Pliys.," art. Thorax), and is nsnally adopU'd in our schools. It
is, liowcvcr, much disputcMl. llanihcri^cr bcJievcMl that tlie External intercostals act as elevators
of the riljs, or rnviscles of ins))iratioii, wliile the Internal act in expiration. Ilaller lanpht that
both sets of mnscles act in common — viz., as mnscles of inspiralicm — and lliis view is adopted by
many of the best anatomists of the (Continent, an'd appears supported by many observations made
Oh the human su1)ject under various conditions of disease, and on livin<j animals in whom the
muscles have been exposed under chloroform. '!'he reader mav consult an interesting,^ paper by
Dr. Cleland, in tlie "Journal of Aii:it. and Phys.," No. II.. Mn'y, 18(m, p. 201), "On the llutchin-
srinian Theory of the Action of the Intercostal Muscles," who refers also to Henle, I>uschka,
IJudt'e, and I5ilumler, " Observat 'ons on the Action of the Intercostal Muscles," Erhingen, 1860.
(In " New .Syd. Soc.'s Ycar-Book for 18C1," p. 09.)
DIAPHRAGMATIC REGION.
395
zontal, the narrow part, wliicli represents the handle of the fan, vertical, and
joined at risht angles to the former. It is from this circumstance that some
anatomists describe it as consisting of two portions, the upper or great muscle
of the Diaphragm, and the lower or lesser muscle. It arises from the whole of
the internal circumference of the thorax, being attached, in front, by fleshy fibres
to the ensiform cartilage ; on either side, to the inner surface of the cartilages
Fig. 264. — The Diaphragm. Uuder Surface.
and bony portions of the six or seven inferior ribs, interdigitating with the Trans-
versalis ; and behind, to two aponeurotic arches, named the ligamentum arcuatum
externum and internum, and to the lumbar vertebra. The fibres from these
sources vary in length ; those arising from the ensiform appendix are very short
and occasionally aponeurotic ; those from the ligamenta arcuata, and more espe-
cially those from the ribs at the side of the chest, are longer, describe well-marked
curves as they ascend, and finally converge to be inserted into the circumference
of the central tendon. Between the sides of the muscular slip from the ensiform
appendix and the cartilages of the adjoining ribs, the fibres of the Diaphragm arc
deficient, the interval being filled by areolar tissue, covered on the thoracic side
by the pleurae; on the abdominal, by the peritoneum. This is, consequentl}^,
a weak point, and a portion of the contents of the abdomen may protrude into
the chest, forming phrenic or diaphragmatic hernia, or a collection of pus in the
mediastinum may descend through it, so as to point at the epigastrium.
The ligaTnentitm arciiatnm, ■internum is a tendinous arch, thrown across the
upper part of the Psoas magnus muscle, on each side of the spine. It is con-
nected, by one end, to the outer side of the body of the first, and occasionally the
second lumbar vertebra, being continuous with the outer side of the tendon of the
396 MUSCLES AND FASCI.E.
corresponding cms ; and, by tlie otlier end, to tlie front of the transverse process
of tlie second lumbar vertebra.
The Ugamentum arcuation extermim is the thickened npper margin of the
anterior lamella of the transversalis fascia ; it arches across the npper part of
the Quadratus Inmboram, being attached, by one extremity, to the front of the
transverse process of the second lumbar vertebra : and, by the other, to the apex
and lower margin of the last rib.
To the spine the Diaphragm is connected by two crnra, which are situated on
the bodies of the lumbar vertebra, on each side of the aorta. The crura, at their
origin, are tendinous in structure ; the right crus, larger and longer than the left,
arising from the anterior surface of the bodies and intervertebral substances of
the second, third, and fourth lumbar vertebrse ; the left, from the second and
third ; both blending with the anterior common ligament of the spine. A tendi-
nous arch is thrown across the front of the vertebral column, from the tendon of
one crus to that of the other, beneath which pass the aorta, vena azygos major,
and thoracic duct. The tendons terminate in two large fleshy bellies, which, with
the tendinous portions above alluded to, are called the crura or pillars of the dia-
phragm. The outer fasciculi of the two crura are directed upwards and outwards
to the central tendon ; but the inner fasciculi decussate in front of the aorta, and
then diverge, so as to surround the oesophagus before ending in the central tendon.
The anterior and larger of these fasciculi is formed by the right crus.
The Central or Gordiform Tendon of the Diaphragm is a thin tendinous apo-
neurosis, situated at the centre of the vault formed by the muscle, immediately
below the pericardium, with which its circumference is blended. It is shaped
somewhat like a trefoil leaf, consisting of three divisions, or leaflets, separated
from one another by slight indentations. The right leaflet is the largest; the
middle one, directed towards the ensiform cartilage, the next in size ; and the left,"
the smallest. In structure, the tendon is composed of several planes of fibres,
which intersect one another at various angles, and unite into straight or curved
bundles — an arrangement which affords it additional strength.
The Openings connected with the Diaphragm are three large and several
smaller apertures. The former are the aortic, the oesophageal, and the opening
for the vena cava.
The aortic opening is the lowest and most posterior of the three large apertures
connected with this muscle. It is situated in the middle line, immediately in
front of the bodies of the vertebrce ; and is, therefore, behind the Diaphragm,
not in it. It is an osseo-aponcurotic aperture, formed by a tendinous arch thrown
across the front of the bodies of the vertebros, from the crus on one side to that
on the other, and transmits the aorta, vena azj^gos major, thoracic duct, and occa-
sionally the left sympathetic nerve.
The oesophageal opening^ elliptical in form, muscular in structure, and formed
by the two crura, is placed above, and, at the same time, anterior, and a little to
the left of the preceding. It transmits the oesophagus and pneumogastric nerves.
The anterior margin of this aperture is occasionally tendinous, being formed by
the margin of the central tendon.
The opening for the vena cava is the highest; it is quadrilateral in form, ten-
dinous in structure, and placed at the junction of the right and middle leaflets of
tlic central tendon, its margins being bounded by four bundles of tendinous fibres,
wliich meet at right angles.
The nV//i^cn/,.s transmits the sympathetic and the greater and lesser splanchnic
nerves of the right side; the leflcrus^ the greater and lesser splanchnic nerves
of the left side, and the vena azygos minor.
The HerouH Mcrnhrane.s in relation with the Diaphragm, arc four in number:
throe lining its upper or tlioracic surface; one its abdominal. The three serous
Tiicmbranes on its npjicr surface are the pleura on cither side, and the serous
layer of the pericardium, which covers the luiddlc portion of the tendiuous
DIAPHRAGM. 397
centre. Tlie serous membrane covering its under surface is a portion of tlie
general peritoneal membrane of tbe abdominal cavity.
The Diaphragm is arched, being convex towards the chest, and concave to
the abdomen. The right portion forms a complete arch from before backwards,
being accurately moulded over the convex surface of the liver, and having rested
upon it the concave base of the right wing. The left portion is arched from
before backwards in a similar manner; but the arch is narrower in front, being
encroached upon by the pericardium, and lower than the right, at its summit,
by about three-quarters of an inch. It supports the base of the left lung, and
covers the great end of the stomach, the spleen and left kidney. The central
portion^ which supports the heart, is higher, in front at the sternum, and behind
at the vertebrge, than the lateral portions ; the reverse is the case in the parts
further removed from the surface of the body.
The height of the Diaphragm is constantly varying during respiration, the
muscle being carried upwards or downwards from the average level ; its height
also varies according to the degree of distension of the stomach and intestines,
and the size of the liver. After a forced expiration, the right arch is on a level,
in front, with the fourth costal cartilage ; at the side, with the fifth, sixth, and
seventh ribs ; and behind, with the eighth rib ; the left arch being usually from
one to two ribs' breadth below the level of the right one. In a forced inspira-
tion, it descends from one to two inches; its slope would then be represented
by a line drawn from the ensiform cartilage towards the tenth rib.
Nerves. The Diaphragm is supplied by the phrenic nerves.
Actions. The action of the Diaphragm modifies considerably the size of the
chest and the position of the thoracic and abdominal viscera. During a forced
inspiration^ the cavity of the thorax is enlarged in the vertical direction from
two to three inches, partly by the ascent of the walls of the chest, partly by the
descent of the Diaphragm. The chest, consequently, encroaches upon the
abdomen: the lungs are expanded, and lowered, in relation with the ribs,
nearly two inches ; the heart being drawn down about an inch and a half; the
descent of the latter organ taking place indirectly through the medium of its
connection with the lungs, as well as directly by means of the central tendon
to which the pericardium is attached. The abdominal viscera are also pushed
down (the liver, to the extent of nearly three inches), so that these organs are
no longer protected by the ribs. During expiration^ when the Diaphragm is
passive, it is pushed up by the action of the abdominal muscles; the cavity of
the abdomen (with the organs contained in it) encroaches upon the chest, by
which the lungs and heart are compressed upwards, and the vertical diameter
of the thoracic cavity diminished. The Diaphragm is passive when raised or
lowered, by the abdominal organs, independently of respiration, in proportion
as they are large or small, full or empty ; hence the oppression felt in the chest
after a full meal, or from flatulent distension of the stomach and intestines.
In all expulsive acts the Diaphragm is called into action, to give additional
power to each expulsive effort. Thus, before sneezing, coughing, laughing, and
crying; before vomiting; previous to the expulsion of the urine and feces, or
of the foetus from the womb, a deep inspiration takes place.^
• For a detailed description of the general relations of the Diaphragm, and its action, refer to
Dr. Sibson's " Medical Anatomy."
J98
MUSCLES AKD FASCIA.
MUSCLES AND FASCIAE OF THE UPPEE EXTEEMITY.
The Muscles of the Upper Extremity are divisible into groups, correspondirig
with the different regions of the limb.
Of the Shoulder.
Anterior Thoracic Region.
Pectoralis major.
Pectoralis minor.
Subclavius.
Lateral TJioracic Region.
Serratns maa-nus.
Deltoid.
Acroinial Region.
Radial Region.
Supinator longus.
Extensor carpi radialis longior.
Extensor carpi radialis brevior.
Posterior Brachial Region.
r Extensor communis digitorum.
j Extensor minimi digiti.
Extensor carpi ulnaris. >
[ Anconeus.
Anterior Scapular Region.
Subscapularis.
Posterior Scapular Region.
Supraspinatus.
Infraspinatus.
Teres minor.
Teres major.
Of the Arm.
Anterior Humeral Region.
Coraco-brachialis.
Biceps.
Brachialis anticus.
Posterior Humeral Region.
Triceps.
Subanconeus.
O F-i
in
o. u
\A-
' Supinator brevis.
Extensor ossis metarcarpi pol-
licis.
J Extensor primi internodii pol-
licis.
Extensor secundi internodii pol-
licis.
Extensor indicis.
Of the Hand.
Radial Region.
Abductor pollicis.
Opponens pollicis (Flexor ossis meta-
carpi).
Flexor brevis pollicis.
Adductor pollicis.
Ulnar Region.
Palmar is brevis.
Abductor minimi digiti.
Flexor brevis minimi digiti.
Opponens minimi digiti (Flexor ossis
metacarpi).
Middle Palmar Region.
Lumbricalcs.
Intcrossci jmlmares.
Intcrossci dorsales.
DiHxc.rtion nf Perioral Re.ginn ami Axilla (Fiir. 265). Tlio arm boiiiji: rirawn away from the
«i(l(j nearly atrifjlit arifrlcs witli tlie trunk, and rotated outwards, make a vertical incision throuf^h
the intcfriiinent in Ihc median line of the chest, from the n])))er to the lower part of the sternum;
a Kecoiid incision ahxifr the lower border of the Pectoral muscle, from the ensiform cartilaj,^c to
the inner side of the axillii ; a third, from the sternum aloiifi' the (clavicle, as far as its centre;
and a fourth, from the tniddh^ fif tlie cliivicle ol)li(|nely downwards, alonir the interspace between
tlie Pectoral and Deltoid mnsch's, iis low as tlie fold of the arm-pit. 'I'he flap of integ'ument is
then to be dissected off in the direction indicated in the fif;nre. but not entirely removed, as it
Klioidd be lephieed on completinfr tint dissection. ]f a transverse incision is now made from the
lf.w(-r end of the sternum to the side of the chest, as far as the ])osterior fold of thi' arm-pit, and
the integument reflected outwards, tlie axillary space will be more completely exposed.
Of the Forearm.
Anterior Brachial Region.
'Pronator radii teres. -
Flexor carpi radialis. -
Palmaris longus.
Flexor carpi ulnaris.
Flexor sublimis digitorum.
Flexor profundus digitorum.
Flexor longus pollicis.
Pronator quadratus.
ANTERIOR THORACIC REGION.
399
S.Disseetcoji of
Fascia of the Thorax.
Tlie superficial fascia of tlie thoracic region is a loose cellulo-fibroTis layer,
continuous with, the superficial fascia of the neck and upper extremity above,
and of the abdomen below ; opposite
the mamma, it subdivides into two Fig. 265.— Dissection of Upper Extremity.
layers, one of which passes in front,
the other behind that gland; and
from both of these layers numerous
septa pass into its substance, sup-
porting its various lobes : from the
anterior layer, fibrous processes pass
forward to the integument and nip-
ple, inclosing in their areolaB masses
of fat. These processes were called
by Sir A. Cooper the ligamenta sus-
pensoria^ from the support they afford
to the gland in this situation. On
removing the superficial fascia with
the mamma the deep fascia of the
thoracic region is exposed: it is a
thin aponeurotic lamina, covering
the surface of the great Pectoral
muscle, and sending numerous pro-
longations between its fasciculi: it
is attached, in the middle line, to
the front of the sternum ; and, above,
to the clavicle : it is very thin over
the upper part of the muscle, some-
what thicker in the interval between
the Pectoralis major and Latissimus
dorsi, where it closes in the axillary
space, and divides at the outer mar-
gin of the latter muscle into two
layers, one of which passes in front,
and the other behind it ; these proceed as far as the spinous processes of the
dorsal vertebree, to which they are attached. At the lower part of the thoracic
region, this fascia is well developed, and is continuous with the fibrous sheath
of the Kecti muscles.
^ofl
FORE-ARM
PALM^^KAiSlO
Anterior Thoracic Eegiox.
Pectoralis Major.
Pectoralis Minor.
Subclavius.
The Pectoralis Major (Fig. 266) is a broad, thick, triangular muscle, situated
at the upper and fore part of the chest in front of the axilla. It arises from the
anterior surface of the sternal half of the clavicle ; from half the breadth of the
anterior surface of the sternum, as low down as the attachment of the cartilage
of the sixth or seventh rib; its origin consisting of aponeurotic fibres, which
intersect with those of the opposite muscle ; it also arises from the cartilages of
all the true ribs, with the exception, frequently, of the first, or of the seventh,
or both ; and from the aponeurosis of the External oblique muscle of the
abdomen. The fibres from this extensive origin converge towards its insertion,
giving to the muscle a radiated appearance. Those fibres which arise from the
clavicle pass obliquely outwards and downwards, and are usually separated
from the rest by a cellular interval: those from the lower part of the sternum
and the cartilages of the lower true ribs, pass upwardb and outwards ; whilst
400
MUSCLES AND FASCIA.
tlie middle fibres pass liorizontallj. As tliese three sets of fibres converge, they
are so disposed that the upper overlap the middle, and the middle the lower
portion, the fibres of the lower portion being folded backwards upon themselves;
so that those fibres which are lowest in front become highest at their point of
Fig. 266. — Muscles of the Chest and Front of the Arm. Superficial View.
insertion. They all terminate in a fiat tendon, al)ont two inches broad, which
is inserted into the anterior bicipital ridge of the humerus. This tendon consists
of two lamina}, ])laccd one in front of the other, and usually blended together
below. Tlic anterior, the thicker, receives the clavicular and upper half of the
sternal portion of the muscle; the posterior lamina, receiving the attachment of
the lower half of the sternal y)ortion. From this arrangement it results, that
th(5 fibres of the np])er and middle ])ortions of the muscle are inserted into the
loAvcr part of the bicipital ridge; those of the lower portion, into the upper
part. The tendon, at its insertion, is connected with that of the Deltoid; it
sends uj) an cxpansi(m over the bicipital groove towards the head of the hume-
ANTERIOR THORACIC REGION. 401
rus ; another backwards, wliicli lines the groove ; and a third to the fascia of
the arm.
Relations. Bj its anterior surface, with the integument, the superficial fascia,
the Platysma, and the mammary gland. By its posterior surface — its thoracic
portion, with the sternum, the ribs and costal cartilages, the Subclavius, Pecto-
ralis minor, Serratus magnus, and the Intercostals ; its axillary j^ortion forms
the anterior wall of the axillary space, and covers the axillary vessels and
nerves. Its upper border lies parallel with the Deltoid, from which it is sepa-
rated by the cephalic vein and descending branch of the thoracico-acromialis
artery. Its lower border forms the anterior margin of the axilla, being at first
separated from the Latissimus dorsi by a considerable interval; but both mus-
cles gradually converge towards the outer part of the space.
Peculiarities. In muscular subjects, the sternal origins of the two Pectoral muscles are sepa-
rated only by a narrow interval ; but this interval is enlarged where these muscles are ill developed.
Very rarely, the whole of the sternal portion is deficient. Occasionally, one or two additional
muscular slips arise from the aponeurosis of the E.Kternal oblique, and become united to the lower
margin of the Pectoralis major. A slender muscular slip is occasionally found lying parallel with
the outer margin of the sternum, overlapping the origin of the pectoral muscle. It is attached,
by one end, to the upper part of the sternum near the origin of the sterno-mastoid ; and, by the
other, to the anterior wall of the sheath of the Rectus abdominis. It has received the name
" Rectus sternalis."
Dissection. Detach the Pectoralis major by dividing the muscle along its attachment to the
clavicle, and by making a vertical incision through its substance a little external to its line of
attachment to the sternum and costal cartilages. The muscle should then be reflected outwards.
and its tendon carefully examined. The Pectoralis minor is now exposed, and immediately above
it, in the interval between its upper border and the clavicle, a strong fascia, the costo-coracoid
membrane.
The costo-coracoid membrane protects the axillary vessels and nerves ; it is
very thick and dense externally, where it is attached to the coracoid process, and
is continuous with the fascia of the arm ; more internally, it is connected with
the lower border of the clavicle, as far as the sternal extremity of the first rib ;
traced downwards, it passes behind the Pectoralis minor, surrounding, in a more
or less complete sheath, the axillary vessels and nerves ; and, above, it sends a
prolongation behind the Subclavius, which is attached to the lower border of
the clavicle, and so incloses the muscle in a kind of sheath. The costo-coracoid
membrane is pierced by the cephalic vein, the thoracico-acromialis artery and
vein, superior thoracic artery, and anterior thoracic nerves.
The Pectoralis Minor (Fig. 267) is a thin, flat, triangular muscle, situated at
the upper part of the thorax, beneath the Pectoralis major. It arises by three
tendinous digitations, from the upper margin and outer surface of the third,
fourth, and fifth ribs, near their cartilages, and from the aponeurosis covering
the Intercostal muscles ; the fibres pass upwards and outwards, and converge to
form a flat tendon, which is inserted into the anterior border of the coracoid
process of the scapula.
Belations. By its anterior surface, with the Pectoralis major, and the superior
thoracic vessels and nerves. By its posterior surface, with the ribs. Intercostal
muscles, Serratus magnus, the axillary space, and the axillary vessels and nerves.
Its upper border is separated from the clavicle by a triangular interval, broad
■ internally, narrow externally, bounded in front by the costo-coracoid membrane,
and internally by the ribs. In this space are seen the axillary vessels and nerves.
The costo-coracoid membrane should now be removed, when the Subclavius muscle will be seen.
The Suhclavius is a long, thin, spindle-shaped muscle, placed in the interval
between the clavicle and the first rib. It arises by a short, thick tendon from
the cartilage of the first rib, in front of the rhomboid ligament ; the fleshy fibres
proceed obliquely outwards, to be inserted into a deep groove on the under sur-
face of the middle third of the clavicle.
Relations. By its upper surface, with the clavicle. By its under surface, it is
separated from the first rib by the subclavian or axillary vessels and brachial
26
402 MUSCLES AND FASCIiE.
plexus of nerves. Its anterior surface is separated from tlie Pectoralis major by
the costo-coracoid aj)oneurosis, which, with the clavicle, forms an osteo-fibrous
sheath in which the muscle is inclosed.
If the costal attacliment of the Pectoralis minor is divided across, and the mnscle reflected
outwards, the axillary vessels and nerves are brought fully into view, and should be examined.
Nerves. The Pectoral muscles are supplied bj the anterior thoracic nerves;
the Subclavius, by a filament from the cord formed by the union of the fifth
and sixth cervical nerves.
Actions. If the arm has been raised by the Deltoid, the Pectoralis major will,
conjointly with the Latissimus dorsi and Teres major, depress it to the side of
the chest; and, if acting singly, it will draw the arm across the front of the chest.
The Pectoralis minor depresses the point' of the shoulder, drawing the scapula
downwards and inwards to the thorax. The Subclavius depresses the shoulder,
drawing the clavicle downwards and forwards. When the arms are fixed, all
three muscles act upon the ribs, drawing them upwards and expanding the chest,
and thus becoming very important agents in forced inspiration. Asthmatic
patients always assume this attitude, fixing the shoulders, so that all these
muscles may be brought into action to assist in dilating the cavity of the chest.
Lateral Thoracic Eegion.
Serratus Magnus.
The Serratus Magnus (Fig. 267) is a broad, thin, and irregularly quadrilateral
muscle, situated at the upper part and side of the chest. It arises by nine fleshy
digitations from the outer surface and upper border of the eight upper ribs (the
second rib having two), and from the aponeurosis covering the upper intercostal'
spaces, and is inserted into the whole length of the inner margin of the posterior
border of the scapula. This muscle has been divided into three portions, a
superior, middle, and inferior, on account of the difference in the direction, and
in the extent of attachment of each part. The upper portion, separated from
the rest by a cellular interval, is a narrow, but thick fasciculus, which arises by
two digitations from the first and second ribs, and from the aponeurotic arch
between them; its fibres proceed upwards, outAvards, and backwards, to be
inserted into the triangular smooth surface on the inner side of the superior
angle of the scapula. The middle portion of the muscle arises by three digita-
tions from the second, third, and fourth ribs ; it forms a thin and broad muscular
layer, which proceeds horizontally backwards to be inserted into the posterior
border of the scapula, between the superior and inferior angles. The lower
])ortion arises from the fifth, sixth, seventh, and eighth ribs, by four digitations,
in the intervals between which are received corresponding processes of the Ex-
ternal oblique; the fibres pass upwards, outwards, and backwards, to be inserted
into the inner surface of the inferior angle of the scapula, hj an attachment
partly muscular, partly tendinous.
Relations. This muscle is covered, in front, by the Pectoral muscles ; behind,
by the Subscapularis ; above, by the axillary vessels and nerves. Its deep surface
rests upon the ribs and Intercostal muscles.
Nerves. Tiic Serratus magnus is supplied by the posterior thoracic nerve.
Actions. The Serratus magnus is the most important external ins])iratory
muscle. When the slioulders are fixed, it elevates the ribs, and so dilates the
cavity of the chest, assisting the Pectoral and Subclavius muscles. This muscle,
cspGciall}'" its middle and lower segments, draws the base and inferior angle of
tlie scapula forwards, and so raises the point of the shoulder by ciusing a rota-
tion of the bf)nc on ihc aide of the chest; assisting the IVapczius muscle in sup-
]»orting weights upon the shouldt^r, the thorax being at the same time fixed by
preventing the escape of ihc inclndiMl air.
LATERAL THORACIC REGION.
40^
Di'ssedton. After completing the dissection of the Axilla, if the muscles of the back have
been dissected, the upper extremity should be separated from the trunk. Saw through the clavicle
at its centre, and then cut through the muscles which connect the scapula and arm with the trunk,
viz., the Pectoralis minor, in front, Serratus magnus, at the side, and the Levator anguli scapulae,
the Rhomboids, Trapezius, and Latissimus dorsi behind. These muscles should be cleaned and
traced to their respective insertions. 'I'hen make an incision through the integument, commencing
at the outer third of the clavicle, and extending along the margin of that bone, the acromion
process, and spine of the scapula; the integument should be dissected from above downwards and
outwards, when the fascia covering the Deltoid is exposed (Fig. 265, No. 3).
Fi"-. 2G7. — Muscles of the Chest and Front of the Arm, with the Boundaries of the Axilla.
The superficial fascia of the upper extremity, is a thin celliilo-fibrous lamina,
containing between its layers the superficial veins and lymphatics, and the cuta-
neous nerves. It is most distinct in front of the elbow, and contains very large
superficial veins and nerves ; in the hand it is hardly demonstrable, the integu-
ment being closely adherent to the deep fascia by dense fibrous bands. Small
subcutaneous bursse are found in this fascia, over the acromion, the olecranon,
and the knuckles. The deep fascia of the upper extremity comprises the
aponeurosis of the shoulder, arm, and forearm, the anterior and posterior annular
ligaments of the carpus, and the palmar fascia. These will be considered in the
description of the muscles of the several regions.
404 MUSCLES AND FASCIA.
ACEOMIAL EeGION.
Deltoid.
The deep fascia covering the Deltoid (deltoid aponeurosis) is a thick and strong
fibrous layer, which incloses the outer surface of the muscles, and sends down
numerous prolongations between its fasciculi ; it is continuous, internally, with
the fascia covering the great Pectoral muscle : behind, with that covering the
Infraspinatus and back of- the arm : above, it is attached to the clavicle, the
acromion, and spine of the scapula.
The Deltoid (Fig. 266) is a large, thick, triangular muscle, which forms the
convexity of the shoulder, and has received its name from its resemblance to
the Greek letter a reversed. It surrounds the shoulder-joint in the greater part
of its extent, covering it on its outer side, and in front and behind. It arises
from the outer third of the anterior border and upper surface of the clavicle ;
from the outer margin and upper surface of the acromion process ; and from
the whole length of the lower border of the spine of the scapula. From this
extensive origin, the fibres converge towards their insertion, the middle passing
vertically, the anterior obliquely backwards, the posterior obliquely forwards ;
they unite to form a thick tendon, which is inserted into a rough prominence
on the middle of the outer side of the shaft of the humerus. This muscle is
remarkably coarse in texture, and intersected by three or four tendinous laminae ;
these are attached, at intervals,. to the clavicle and acromion, extend into the
substance of the miuscle, and give origin to a number of fleshy fibres. The
largest of these laminte extends from the summit of the acromion.
Relations. By its superficial surface.^ with the integument, the superficial
fascia, Platysma, and supra-acromial nerves. Its deep surface is separated from
the head of the humerus by a large sacculated synovial bursa, and covers the
coracoid process, coraco-acromial ligament, Pectoralis minor, Coraco-brachialis,
both heads of the Biceps, tendon of the Pectoralis major. Infraspinatus, Teres
minor. Triceps (its scapular and external heads), the circumflex vessels and
nerve, and the humerus. Its anterior horder is separated from the Pectoralis
major by a cellular interspace, which lodges the cephalic vein and "descending
branch of the thoracico-acromialis artery. Its posterior horder rests on the
Infraspinatus and Triceps muscles.
Nerves. The Deltoid is supplied by the circumflex nerve.
'Actions. The Deltoid raises the arm directly from the side, so as to bring it
at right angles with the trunk. Its anterior fibres, assisted by the Pectoralis
major, draw the arm forwards ; and its posterior fibres, aided by the Teres
major and Latissimus dorsi, draw it backwards.
])if!.sect?rm. Divide the Deltoid across, near its upper part, by an incision carried alongf the
niarfrin of the clavicle, the acromion process, and spine of Ihe scapula, and reflect it downwards;
ihe l)ursa will l)e seen on ils under surface, as well as the circumflex vessels and nerve. The
insertion of the muscle should be carefully examined.
Anterior Scapular Region.
Subscapularis.
The suhsrajndar aponeurosis is a thin membrane, attached to the entire cii'cum-
fercnce of the subscaj)ular fossa, and afl'ording atlachiiicnt by its inner surface
to some of the fibres of the Subsca|)iilai'is muscle: wlu'ii lliis is removed, the
Subsca])nlaris muscle is exposed.
The Snhscapnlaris (Fig. 267) is a large triangular muscle, which fills up the
subscapular fossa, arising frf)m its internal two-thirds, with the exception of a
narrow margin along the y)ostcrior border, and the inner side of the superior
and inferior angles, which aflord atlachment to the Scrratus magnus. Some
fibres arise from tendinous lamimc, which intersect the muscle, and arc attached
POSTERIOE SCAPULAR REGION. 405
to ridges on tlie bone ; and others from an aponeurosis, wliich separates the
muscle from the Teres major and the. long head of the Triceps. The fibres pass
outwards, and, gradually converging, terminate in a tendon, which is inserted
into the lesser tuberosity of the humerus. Those fibres which arise from the
axillary border of -the scapula are inserted into the neck of the humerus to the
extent of an inch below the tuberosity. The tendon of the muscle is in close
contact with the capsular ligament of the shoulder-joint, and glides over a large
bursa, which separates it from the base of the coracoid process. This bursa
communicates with the cavity of the joint by an aperture in the capsular liga-
ment.
Relations. By its anterior surface.^ with the Serratus magnus, Coraco-brachialis,
and Biceps, and the axillary vessels and nerves. By its posterior surface^ with
the scapula, the subscapular vessels and nerves, and the capsular ligament of
the shoulder-joint. Its lower border is contiguous with the Teres Major and
Latissimus dorsi.
Nerves. It is supplied by the uppeT and lower subscapular nerves.
Actions. The Subscapularis rotates the head of the humerus inwards ; when
the arm is raised, it draws the humerus dowuAvards. It is a powerful defence
to the front of the shoulder -joint, preventing displacement of the head of the
bone forwards.
Posterior Scapular Eegion. (Fig. 268.)
Supraspinatus. Teres Minor.
Infraspinatus. Teres Maj or.
Dissection. To expose thep.e muscles, and to examine their mode of insertion into the humerus,
detach the Deltoid and Trapezius from their attachment to the spine of the scapula and acromion
process. Remove the clavicle by dividing the ligaments connecting it with the coracoid process,
and separate it at its articulation with its scapula : divide the acromion process near its root with
a saw. The fragments being removed, the tendons of the posterior Scapular muscles will be fully
exposed, and can be examined. A block should be placed beneath the shoulder-joint, so as to
make the muscles tense.
The supraspinous aponeurosis is a thick and dense membranous layer, which
completes the osseo-fibrous case in which the Supraspinatus muscle is contained ;
affording attachment, by its inner surface, to some of the fibres of the muscle.
It is thick internally, but thinner externally under the coraco-acromial ligament.
When this fascia is removed, the Supraspinatus muscle is exposed.
The Supraspinatus muscle occupies the whole of the supraspinous fossa,
arising from its internal two-thirds, and from the strong fascia which covers its
surface. The muscular fibres converge to a tendon, which passes across the
capsular ligament of the shoulder-joint, to which it is intimately adherent, and
is inserted into the highest of the three facets on the great tuberosity of the
humerus.
Relations. By its upper surface^ with the Trapezius, the clavicle, the acromion,
the coraco-acromial ligament, and the Deltoid. By its under surface., with the
scapula, the suprascapular vessels and nerve, and upper part of the shoulder-
joint.
The infraspinous aponeurosis is a dense fibrous membrane, covering in the
Infraspinatus muscle, and attached to the circumference of the infraspinous fossa;
it affords attachment, by its inner surface, to some fibres of that muscle, is con-
tinuous externally with the fascia of the arm, and gives off from its under surface
intermuscular septa, which separate the Infraspinatus from the Teres minor,
and the latter from the Teres major.
The Infraspinatus is a thick triangular muscle, which occupies the chief part
of the infraspinous fossa, arising by fleshy fibres, from its internal two-thirds ;
and by tendinous fibres, from the ridges on its surface ; it also arises from a strong
fascia which covers it externally, and separates it from the Teres major and
minor. The fibres converge to a tendon, which glides over the external border
406
MUSCLES AND FASCIiE.
of tlie spine of tlie scapula, and, passing across the capsular ligament of the
shoulder -joint, is inserted into the middle facet on the great tuberosity of the
humerus. The tendon of this muscle is occasionally separated from the spine of
the scapula by a synovial bursa, which communicates with the synovial mem-
brane of the shoulder-joint.
Fig. 268. — Muscles ou the Dorsum of the Scapula and the Triceps.
Relations. By its posterior surface^ with the Deltoid, lhe Trapezius, Latissimus
dorsi, and the integument. By its anterior surface^ with the scapula, from which
it is separated by the suprascapular and dorsalis scapulte vessels, and with the
capsular ligament of the shoulder -joint. Its loiver horder is in contact with the
Teres minor, and occasionally united with it, and with the Teres major.
The Teres Minor is a narrow, elongated muscle, which lies along the inferior
border of the scapula. It arises from the dorsal surface of the axillary border
of the scapula for the upper two-thirds of its extent, and from two aponeurotic
laminse, one of which separates this muscle from the Infraspinatus, the other
from the Teres major ; its fibres pass obliquely upwards and outwards, and termi-
nate in a tendon, which is inserted into the lowest of the three facets on the great
tuVjorosity of the humerus, and, by fleshy fibres, into the humerus, immediately
below it. The tendon of this muscle passes across the capsular ligament of the
shonldcr-joint.
Rehitions. By its posterior snrface^ with the Deltoid, the Latissimus dorsi, and
the integument. By its anterior surface^ with the scapula, the dorsal branch of
the subscfipnlar artery, the long head of the Triceps, and the shoulder-joint.
By its v,pj,er horder^ with the infrasi)inatus. By its lower horder, with the Teres
major, from which it is separated anteriorly by the long head of the Triceps.
The Teres Major is a broad and somewhat flattened muscle, whicli arises from
. ANTERIOR HUMERAL REGION. 407
tlie dorsal aspect of tlie inferior angle of tlie scapula, and from the fibrous septa
interposed between it and the Teres minor and iDfraspinatus ; the fibres are
directed upwards and outwards, and terminate in a flat tendon, about two inches
in length, which is inserted into the posterior bicipital ridge of the humerus.
The tendon of this muscle, at its insertion into the humerus, lies behind that of
the Latissimus dorsi, from which it is separated by a synovial bursa.
Relations. By its posterior surface^ with the integument, from which it is
separated, internally, by the Latissimus dorsi ; and externally, by the long head
of the Triceps. By its anterior surface^ with the Subscapularis, Latissimus dorsi,
Coraco-brachialis, short head of the Biceps, the axillary vessels, and brachial
plexus of nerves. Its upper border is at first in relation with the Teres minor,
from which it is afterwards separated by the long head of the Triceps. Its lower
border forms, in conjunction with the Latissimus dorsi, part of the posterior
boundary of the axilla.
Nerves. The Supraspinatus and Infraspinatus muscles are supplied by the
suprascapular nerve ; the Teres minor, by the circumflex, and the Teres major,
by the lower subscapular.
Actions. The Supraspinatus assists the Deltoid in raising the arm from the
side, and fixes the head of the humerus in its socket. The Infraspinatus and
Teres minor rotate the head of the humerus outwards: when the arm is raised,
they assist in retaining it in that position, and carrying it backwards. One of
the most important uses of these three mu.scles is the great protection they
afford to the shoulder-joint, the Supraspinatus supporting it above, and pre-
venting displacement of the head of the hu.merus upwards, whilst the Infra-
spinatus and Teres minor protect it behind, and prevent dislocation backwards.
The Teres major assists the Latissimus dorsi in drawing the humerus downwards
and backwards when previously raised, and rotating it inwards; when the arm
is fixed, it may assist the Pectoral and Latissimus dorsi muscles in drawing the
trunk forwards.
Anterior Humeral Eegion. (Fig. 267.)
Coraco-brachialis. Biceps. Brachialis Anticus.
Dissection. The arm beiii"- placed on the table, with the front surface uppermost, make a
vertical incision through the integument along the middle line, from the middle of the interval
between the folds of the axilla, to about two inches below the elbow-joint, where it should be
joined by a transverse incision, extending from the inner to the outer side of the forearm; the
two flaps being reflected on either side, the fascia should be examined.
The deep fascia of the arm, continu.ous with that covering the shoulder and
front of the great Pectoral muscle, is attached, above, to the clavicle, acromion,
and spine of the scapula ; it forms a thin, loose, membranous sheath investing
the muscles of the arm, sending down septa between them, aad composed of
fibres disposed in a circular or spiral direction, and connected together by verti-
cal fibres. It differs in thickness at different parts, being thin over the Biceps,
but thicker where it covers the Triceps, and over the condyles of the humerus;
it is strengthened by fibrous aponeuroses, derived from the Pectoralis major and
Latissimus dorsi, on the inner side, and from the Deltoid externally. On either
side it gives off a strong intermuscular septum^ which is attached to the con-
dyloid ridge and condyle of the humerus. These septa serve to separate the
muscles of the anterior from those of the posterior brachial region. The exter-
nal intermuscular septum extends from the lower part of the anterior bicipital
ridge, along the external condyloid ridge, to the outer condyle ; it is blended
with the tendon of the Deltoid; gives attachment to the Triceps behind, to the
Brachialis anticus, Supinator longus, and Extensor carpi radialis longior, in
front ; and is perforated by the musculo-spiral nerve, and superior profunda
artery. The internal intermuscular septum, thicker than the preceding, extends
from the lower part of the posterior lip of the bicipital groove below the Teres
408 MUSCLES AND FASCIA.
majoT, along tlie internal condyloid ridge to tlie inner condyle; it is blended
with tlie tendon of the Coraco-brachialis, and affords attachment to the Triceps
behind, and the Brachialis anticus in front. It is perforated by the ulnar nerve,
and the inferior profunda and anastomotic arteries. At the elbow, the deep
fascia is attached to all the prominent points ronnd the joint, and is continuous
with the fascia of the forearm. On the removal of this fascia, the muscles of
the anterior humeral region are exposed.
The Coraco-hrachialis^ the smallest of the three muscles in this region, is
situated at the upper and inner part of the arm. It arises by fleshy fibres from
the apex of the coracoid process, in common with the short head of the Biceps,
and from the intermuscular septum between the two muscles; the fibres pass
downwards, backwards, and a little outwards, to be inserted by means of a flat
tendon into a rough ridge at the middle of the inner side of the shaft of the
humerus. It is perforated by the musculo-cutaneous nerve. The inner border
of the muscle forms a guide to the position of the vessel, in tying the brachial
artery in the upper part of its course.
Relations. By its anterior surface.^ with the Deltoid and Pectoralis major
above, and at its insertion with the brachial vessels and median nerve Avhich
cross it. By its posterior surface^ with the tendons of the Subscapularis, Latissi-
mus dorsi, and Teres major, the short head of the Triceps, the humerus, and the
anterior circumflex vessels. By its inner border^ with the brachial artery, and
the median and musculo-cutaneous nerves. By its outer horder^ with the short
head of the Biceps and Brachialis anticus.
The Biceps is a long fusiform muscle, occupying the whole of the anterior
surface of the arm, and divided above into two portions or heads, from which
circumstance it has received its name. The short head arises by a thick flattened
tendon from the apex of the coracoid process, in common with the Coraco-
brachialis. The long head arises from the upper margin of the glenoid cavitj^,
by a long rounded tendon, which is continuous with the glenoid ligament. This
tendon arches over the head of the humerus, being inclosed in a special sheath
of the synovial membrane of the shoulder-joint; it then pierces the capsular
ligament at its attachment to the humerus, and descends in the bicipital groove
in which it is retained by a fibrous prolongation from the tendon of the Pecto-
ralis major. The fibres from this tendon form a rounded belly, and about the
middle of the arm, join with the portion of the muscle derived from the short
head. The belly of the muscle, narrow and somewhat flattened, terminates
above the elbow in a flattened tendon, which is inserted into the back part of
the tuberosity of the radius, a synovial bursa being interposed between the
tendon and the front of the tuberosity. The tendon of the muscle is thin and
broad ; as it approaches the radius it becomes narrow and tAvisted upon itself,
being applied by a flat surface to the back part of the tuberosity : opposite the
bend of tlie clb<nv the tendon gives off", from its inner side, a broad aponeurosis,
tlie bicipital fascia, which passes obliquely downwards and inwards across the
brachial artery, and is conjinuous with the fascia of the forearm (Fig. 26G). The
inner border of this muscle forms a guide to the position of the vessel, in tying
the brachial artery in the middle of the arm.'
Relations. Its anterior surface is overla]-)pcd above by the Pectoralis major
and Deltoid ; in the rest of its extent it is covered by the superficial and deep
fasciai and the integument. Its posterior surface rests on the shoulder -joint and
liutncriis, from which it is separated by tlie Subscapularis, Teres major, Latissi-
iiius dorsi. Bi'achialis anticus, and the musculo-cutaneous nerve. Its inner border
' A third liojul to the Biceps is occasionally fotuid ('I'hoile says as often as once in oiiilil, or
nine subjects), iiri.sin{( at the upper and inner jiart of the Uradiiiilis unlicns, willi tlie (ibres of
which it is continuous, and inscrtr'd into llu; bicipital fascia and iiuier sid(! of the tendon of the
I>ic(;ps. In most cases, this additional slip passes behind the lirnchial artery in its course down
the arm. Occasionally, the third head consists of two slips, wiiich pass down, one in front, the
otiicr behind the artery, concealing the vessel in the lower half of the arm.
POSTERIOK HUMERAL REGION. 409
is in relation witli the Coraco-bracliialis, the brachial vessels, and median
nerve ; its outer harder^ with the Deltoid and Supinator longus.
The Brachialis Anticus is a broad muscle, which covers the elbow-joint and
the lower half of the front of the humerus. It is somewhat compressed from
before backward, and is broader in the middle than at either extremity. It
arises from the lower half of the outer and inner surfaces of the shaft of the
humerus : and commences above at the insertion of the Deltoid, which it embraces
bj two angular processes. Its origin extends below, to within an inch of the
margin of the articular surface, and is limited on each side by the external and
internal borders of the shaft of the humerus. It also arises from the intermuscular
septa on each side, but more extensively from the inner than the oiiter. Its
fibres converge to a thick tendon, which is inserted into a rough depression on
the anterior surface of the coronoid process of the ulna, being received into
an interval between two fleshy slips of the Flexor digitorum profundus.
Relations. By its anterior surface, with the Biceps, the brachial vessels, mus-
culo-cutaneous and median nerves. By its posterior surface^ with the humerus
and front of the elbow-joint. By its inner border ., with the Triceps, ulnar nerve,
and Pronator radii teres, from which it is separated by the intermuscular septum.
By its outer border^ with the musculo-spiral nerve, radial recurrent artery, the
Supinator longus, and Extensor carpi radialis longior.
Nerves. The muscles of this group are supplied by the musculo-cutaneous
nerve. The Brachialis anticus usually receives an additional filament from the
musculo-spiral.
Actions. The Coraco-brachialis draws the humerus forwards and inwards, and
at the same time assists in elevating it towards the scapula. The Biceps and
Brachialis anticus are flexors of the forearm: the former muscle is also a supi-
nator, and serves to render tense the fascia of the forearm by means of the broad
aponeurosis given off" from its tendon. When the forearm is fixed, the Biceps
and Brachialis anticus flex the arm upon the forearm, as is seen in efforts of
climbing. The Brachialis anticus forms an important defence to the elbow -joint.
PosTEKioE Humeral Eegiojst.
Triceps. Subanconeus.
The Triceps (Fig. 268) is situated on the back of the arm, extending the entire
length of the posterior surface of the humerus. It is of large size, and divided
above into three parts; hence its name. These three portions have been named,
(1) the middle, scapular, or long head, (2) the external, or long humeral, and (3)
the internal, or short humeral head.
The middle or scapular head arises, by a flattened tendon, from a rough trian-
gular depression, immediately below the glenoid cavity, being blended at its
upper part with the capsular and glenoid ligaments; the muscular fibres pass
downwards between the two other portions of the muscle, and join with them
in the common tendon of insertion.
The external head arises from the posterior surface of the shaft of the humerus,
between the insertion of the Teres minor and the upper part of the musculo-
spiral groove, from the external border of the humerus and the external inter-
muscular septum : the fibres from this origin converge towards the common
tendon of insertion.
The internal head arises from the posterior surface of the shaft of the humerus,
below the groove for the musculo-spiral nerve, commencing above, narrow and
pointed, below the insertion of the Teres major, and extending to within an inch
of the trochlear surface : it also arises from the internal border of the humerus
and internal intermuscular septum. The fibres of this portion of the muscle are
directed, some downwards to the olecranon, whilst others converge to the common
tendon of insertion.
The common tendon of the Triceps commences about che middle of the back
410 MUSCLES AND FASCIA.
part of tlie muscle : it consists of two aponeurotic lamina, one of wliicli is sub-
cutaneous and covers the posterior surface of the muscle for the lower half of its
extent : the other is more deeply seated in the substance of the muscle : after
receiving the attachment of the muscular fibres, they join together above the
elbow, and are inserted into the back part of the under surface of the elecranon
process, a small bursa, occasionally multilocular, being interposed between the
tendon and front of this surface.
The long head of the Triceps descends between the Teres minor and Teres
major, dividing the triangular space between these two muscles and the humerus
into two smaller spaces, one triangular, the other quadrangular (Fig. 268), The
triangular space contains the dorsalis scapula vessels ; it is bounded by the
Teres minor above, the Teres major below, and the scapular head of the Triceps
externally : the quadrangular space transmits the posterior circumflex vessels
and nerve; it is bounded by the Teres minor above, the Teres major below, the
scapular head of the Triceps internally, and the humerus externally.
Belations. By its posterior surface^ with the Deltoid above : in the rest of its
extent it is subcutaneous. By its anterior surface^ with the humerus, musculo-
spiral nerve, superior profunda vessels, and back part of the elbow -joint. Its
middle or long head is in relation, behind, with the Deltoid and Teres minor ; in
front, with the Subscapularis, Latissimus dorsi, and Teres major.
The Suhanconeus is a small muscle distinct from the Triceps, and analogous
to the Subcrureus in the lower limb. It may be exposed by removing the
Triceps from the lower part of the humerus. It consists of one or two slender
fasciculi, which arise from the humerus, immediately above the olecranon fossa,
and are inserted into the posterior ligament of the elbow-joint.
Nerves. The Triceps and Subanconeus are supplied by the musculo-spiral
nerve.
Actions. The Triceps is the great Extensor muscle of the forearm ; serving,
when the forearm is flexed, to draw it into a right line with the arm. It is the
direct antagonist of the Biceps and Brachialis anticus. When the arm is ex-
tended, the long head of the muscle may assist the Teres major and Latissimus
dorsi in drawing the humerus backwards. The long head of the Triceps pro-
tects the under part of the shoulder-joint, and prevents displacement of the head
of the humerus downwards and backwards.
Muscles of the Foeeaem.
Difinection. To disseot the forearm, place the limh in the position indicated in Fig. 265; make
a vortical incision along the middle line from the elbow to the wrist, and a transverse incision at
each extremity of this; the flaps of integument being removed, the fascia of the forearm is exposed.
Tiic deep fascia of the forearm, continuous above with that inclosing the arm,
is a dense highly glistening aponeurotic investment, which forms a general sheath
inclosing the muscles in this region ; it is attached behind to the olecranon and
posterior border of the ulna, and gives off' from its inner surface numerous inter-
muscular septa, which inclose each muscle separately. It consist of circular and
(jblif I uc fibres, connected together by numerous vertical fibres. It is much thicker
on the dorsal tlian on the palmar surface, and at the lower than at the upper
part of the forearm, and is strengthened by tendinotts fibres derived from the
Brachialis anticus and Biceps in front, and from the Triceps behind. lis inner
surface gives origin to muscular fibres, especially at the upper part of the inner
and outer sides of the forearm, iiixl lonris the boundaries of a series of conical-
8ha|)(!d cavities, in which tlie muscles arc contained. Besides the vertical septa
scpn rating eafli mu.sclc, transverse se])ta are given ofi" botli on the anterior and
postcrif)r surfaces of the foniarm, separating the deep IVoiii the superficial layer
of muscles. Numerous apertures exist in the fascia lor the passage of vessels
and nerves; one of these, of large size, situated at the front of the elbow, serves,
for the passage of a communicating branch between the superficial and deep veins.
ANTERIOR BRACHIAL REGION.
411
Tlie muscles of the forearm may be subdivided into groups corresponding to
tb.e region tliey occupy. One group occupies the inner and anterior aspect of
the forearm, and comprises the Flexor and Pronator muscles. Another group
occupies its outer side ; and a third, its posterior aspect. The two latter groups
include all the Extensor and Supinator muscles.
Anterior Brachial Eegion.
Superficial Layer.
Pronator Radii Teres. Flexor Carpi Ulnaris.
Flexor Carpi Radialis. Flexor Sublimis Digitorum.
Palmaris Longus.
These muscles take origin from the internal con-
dyle of the humerus by a common tendon.
The Pronator Radii Teres arises by two heads.
One, the larger and more superficial, arises from the
humerus, immediately above the internal condyle,
and from the tendon common to the origin of the
other muscles ; also from the fascia of the forearm,
and intermuscular septum between it and the Flexor
carpi radialis. The other head is a thin fasciculus,
which arises from the inner side of the coronoid pro-
cess of the ulna, joining the preceding at an acute
angle. Between the two heads passes the median
nerve. The muscle passes obliquely across the fore-
arm from the inner to the outer side, and terminates
in a flat tendon, which turns over the outer margin
of the radius, and is inserted into a rough ridge at
the middle of the outer surface of the shaft of that
bone.
Variations. The coronoid origin of this muscle presents
numerous variations. It is occasionalTy absent, and in one case
recorded by Dr. Macalister [Journal of Anat. and Phys. 2d
series, No. 1. p. 9), it existed as a distinct muscle, inserted into
the front of the radius higher up than the rest of the mass. In
other cases the coronoid slip has been found connected with the
Palmaris longus or the Flexor carpi radialis, instead of the
Pronator teres, and other slighter anomalies have been recorded
by Dr. Macalister.
Relations. By its anterior surface., with the deep
fascia, the Supinator longus, and the radial vessels
and nerve. By its posterior surface., with the Bra-
chialis anticus. Flexor sublimis digitorum, the me-
dian nerve, and ulnar artery : the small, or deep,
head being interposed between the two latter struc-
tures. Its outer border forms the inner boundary of
a triangular space, in which is placed the brachial
artery, median nerve, and tendon of the Biceps
muscle. Its inner horder is in contact with the
Flexor carpi radialis.
The Flexor Carpi Radialis lies on the inner side
of the preceding muscle. It arises from the internal
condyle by the common tendon, from the fascia
of the forearm, and from the intermuscular septa
between it and the Pronator teres, on the outside ;
the Palmaris longus, internally; and the Flexor
Fig. 269.— Front of the Left
Forearm. Superficial Muscles.
412 MUSCLES AND FASCIA.
sublimis digitorum, beneatli. Slender and aponeurotic in structure at its com-
mencement, it increases in size, and terminates in a tendon which forms the
lower two-thirds of its length. This tendon passes through a canal on the outer
side of the annular ligament, runs through a groove in the os trapezium (which
is converted into a canal by a fibrous sheath, and lined bj a synovial membrane),
and is inserted into the base of the metacarpal bone of the index finger. The
radial artery lies between the tendon of this muscle and the Supinator longus,
and may easily be tied in this situation.
Relations. By its superficial surface^ with the deep fascia and the integument.
By its deep surface^ with the Flexor sublimis digitorum, Flexor longus pollicis
and wrist-joint. By its outer border^ with the Pronator radii teres, and the radial
vessels. By its inner border^ with the Palmaris longus above, and the median
nerve below.
Mr. J. Wood describes a muscle occasionally found (6 times in 70 subjects) beneath the Flexor
carpi radialis, and which he has named the Flexor carpi radialis brevis vel proi'uudus. In the
best marked specimen it arose from the outer side of the front surface of the radius, above the
Pronator quadratus, and below the Flexor longus pollicis, and was inserted into the base of the
middle metacarpal bone and os magnum ; but several variations are described, both in its origiu
and insertion. Mr. Norton has also found an instance of a similar muscle attached to the middle
metacarpal bone. Journ. of Anat. and Phys., Nov. 1866, p. 55.
The Palmaris Longus is a slender, fusiform muscle, lying on the inner side of
the preceding. It arises from the inner condyle of the humerus by the common
tendon, from the deep fascia, and the intermuscular septa between it and the
adjacent muscles. It terminates in a slender flattened tendon, which is inserted
into the annular ligament, expanding to end in the palmar fascia.
Variations. This muscle is often absent; when present, it offers many varieties. Its fleshy
belly is sometimes very long, or may occupy the middle of the muscle, which is tendinous at either
extremity ; or the Palmaris may be muscular at its lower extremity, its upper part being tendinous.
Occasionally, there is a second Palmaris longus placed on the inner side of the preceding, termi-
nating, below, partly in the annular ligament or fascia, and partly in the small muscles of the
little finger.
Relations. By its svperfi.cial surface., with the deep fascia. By its deep surface.,
with the Flexor sublimis digitorum. Internally^ with the Flexor carpi ulnaris.
Externally., with the Flexor carpi radialis. The median nerve lies close to the
tendon, just above the wrist, on its inner and posterior side.
The Flexor Carpi Ulnaris lies along the ulnar side of the forearm. It arises
by two heads, connected by a tendinous arch, beneath which pass the ulnar
nerve, and posterior ulnar recurrent artery. One head arises from the inner
condyle of the humerus by the common tendon ; the other, from the inner margin
of the olecranon, by an aponeurosis from the upper two-thirds of the posterior
border of the ulna, and from the intermuscular septum between it and the
Flexor sublimis digitorum. The fibres terminate in a tendon, which occupies
the anterior part of the lower half of the muscle, and is inserted into the pisiform
bone, some fibres being prolonged to the annular ligament and base of the meta-
carpal bone of the little finger. The ulnar artery lies on the outer side of the
tendon of this muscle, in the lower two-thirds of the forearm ; the tendon form-
ing a guide in tying the vessel in this situation.
Relations. By its superficial surface., witli the dec]) fascia, witli Avhich it is
intimately cr)nnccted for a considerable extent. By its deep surface., with the
Flexor sublimis, the Flexor profundus, the Pronator quadratus, and the ulnar
vessels and nerve. By its outer or radial border with the Palmaris longus above,
and the ulnar vessels and nerve below.
The Flexor Sublimis Jh'f/itoru^n [perforatv.s) is ])l:icc(l bcucalli llie preceding
muscles, whicli therefore must bo removed in order to bring its attacliment into
view. It is tlie largest of tlie musch^s of the superficial layer, and arises by
three heads. One head arises from ihr internal condyle of the humerus by the
common tendon, from the internal lateral ligament of the elbow-joint, and from
ANTERIOR BRACHIAL REGION. 413
the intermuscular septum common to it and the preceding muscles. The second
head arises from the inner side of the coronoid process of the ulna, above the
ulnar origin of the Pronator radii teres (Fig. 183, p. 229). The third head
arises from the oblique line of the radius, extending from the tubercle to the
insertion of the Pronator radii teres. The fibres pass vertically downwards,
forming a broad and thick muscle, which divides into four tendons about the
middle of the forearm ; as these tendons pass beneath the annular ligament into
the palm of the hand, they are arranged in pairs, the anterior pair corresponding
to the middle and ring fingers ; the posterior pair to the index and little fingers.
The tendons diverge from one another as they pass onwards, and are finally
inserted into the lateral margins of the second phalanges, about their middle.
Opposite the base of the first phalanges, each tendon divides so as to leave a
fissured interval, between which passes one of the tendons of the Flexor pro-
fundus, and the tendons of both the Flexors then enter an osseo-aponeurotic
canal, formed by a strong fibrous band, which arches across them, and is attached
on each side to the margins of the phalanges. The two portions into which the
tendon of the Flexor sublimis divides, so as to admit of the passage of the deep
flexor, expand somewhat, and form a grooved channel, into which the accom-
panying deep flexor tendon is received ; the two divisions then unite, and finally
subdivide a second time, to be inserted into the fore part and sides of the second
phalanges (Fig. 274). The tendons, whilst contained in the fibro-osseous canals,
are connected to the phalanges by slender tendinous filaments, called vincula
accessoria tendinum. A synovial sheath invests the tendons as they pass beneath
the annular ligament ; a prolongation from which surrounds each tendon as it
passes along the phalanges.
Relations. In the forearm, by its superficial surface.^ with the deep fascia and
all the preceding superficial muscles; by its deep surface.^ with the Flexor pro-
fundus digitorum. Flexor longus pollicis, the ulnar vessels and nerve, and the
median nerve. In the hand, its tendons are in relation, in front., with the
palmar fascia, superficial palmar arch, and the branches of the median nerve;
hehind. with the tendons of the deep flexor and the Lumbricales.
Anterior Brachial Region,
Deep Layer.
Flexor Profundus Dio-itorum. Flexor Long;us Pollicis.
Pronator Quadratus.
Dissection. Divide each of the superficial muscles at its centre, and turn either end aside;
the deep layer ol' muscles, together with the median nerve and ulnar vessels, will then be exposed.
The Flexor Profundus Digitorum {perforans) (Fig. 270) is situated on the
ulnar side of the forearm, immediately beneath the superficial Flexors. 'It
arises from the upper two-thirds of the anterior and inner surfaces of the shaft
of the ulna, embracing the insertion of the Brachialis anticus above, and ex-
tending, below, to within a short distance of the Pronator quadratus. It also
arises from a depression on the inner side of the coronoid process, by an aponeu-
rosis from the upper two-thirds of the posterior border of the u.lna, and from
the ulnar half of the interosseous membrane. The fibres form a fleshy belly of
considerable size which divides into four tendons : these pass under the annular
ligament beneath the tendons of the Flexor sublimis. Opposite the first pha-
langes, the tendons pass between the two slips of the tendons of the Flexor
sublimis, and are finally inserted into the bases of the last phalanges. The
tendon of the index finger is distinct; the rest are connected together by cellular
tissue and tendinous slips, as far as the palm of the hand.
Four small muscles, the Lumbricales, are connected with the tendons of the
Flexor profundus in the palm. They will be described with the muscles in
that region.
414
MUSCLES AND FASCIA.
Fig. 270.— Front of the Left Forearm. Deep Muscles.
Relations. Bj its superficial sur-
face^ in the forearm, with the
Flexor sublimis digitorum, the
Flexor carpi ulnaris, the ulnar ves-
sels and nerve, and the median
nerve; and in the hand, with the
tendons of the superficial Flexor,
By its deep surface^ in the forearm,
with the ulna, the interosseous
membrane, the Pronator quadra-
tns: and in the hand, with the
Interossei, Adductor pollicis, and
deep palmar arch. By its ulnar
harder, with the Flexor carpi ul-
naris. By its radial border, with
the Flexor longus pollicis, the
anterior interosseous vessels and
nerve being interposed.
The Flexor Longus Pollicis is
situated on the radial side of the
forearm, lying on the same plane
as the preceding. It arises from
the upper two-thirds of the grooved
anterior surface of the shaft of the
radius ; commencing, above, imme-
diately below the tuberosity and
oblique line, and extending, below,
to within a short distance of the
Pronator quadratus. It also arises
from the adjacent part of the inter-
osseous membrane, and occasion-
ally by a fleshy slip from the base
of the coronoid process. The
fibres pass downwards, and termi-
nate in a flattened tendon, which
passes beneath the annular liga-
ment, is then lodged in the inter-
space between the two heads of
the Flexor brevis pollicis, and
entering an osseo-aponeurotic
canal similar to those for the
other flexor tendons, is inserted
into the base of the last phalanx
of the thumb.
Relations. By its superficial
surface, with the Flexor sublimis
digitorum, Flexor carpi radialis,
8u|)iiiator longus and radial ves-
sels. By its deep surface, with the
radius, interosseous membrane,
,an(l Pronator quadratus. By its
vJiKir harder, will) llic Flexor pro-
i'liiiilus (ligilorum, fj'om which it
is separated l)y the aulerior inter-
osseous vessels and nerve.
The Pronator Qnadratus is a
small, flat, quadrilateral muscle,
RADIAL REGION. 415
extending transversely across tlae front of the radius and ulna, above their
carpal extremities. It arises from the oblique line on the lower fourth of the
anterior surface of the shaft of the ulna, and the surface of bone immediately
below it; from the anterior border of the ulna; and from a strong aponeurosis
which covers the inner third of the muscle. The fibres pass horizontally out-
wards, to be inserted into the lower fourth of the anterior surface and external
border of the shaft of the radius.
Relations. By its superficial surface^ with the Flexor profundus digitorum,
the Flexor longus pollicis, Flexor carpi radialis, and the radial vessels. By its
deep surface, with the radius, ulna, and interosseous membrane.
Nerves. All the muscles of the superficial layer are supplied by the median
nerves, excepting the Flexor carpi ulnaris, which is supplied by the ulnar. Of
the deep layer, the Flexor profundus digitorum is supplied conjointly by the
ulnar and by the median, through its branch, the anterior interosseous nerve,
which also supplies the Flexor longus pollicis and Pronator quadratus.
Actions. These muscles act upon the forearm, the wrist, and hand. Those
acting on the forearm, are the Pronator radii teres and Pronator quadratus,
which rotate the radius upon the ulna, rendering the hand prone ; when prona-
tion has been fully effected, the Pronator radii teres assists the other muscles in
flexing the forearm. The flexors of the wrist are the Flexor carpi ulnaris and
radialis ; and the flexors of the phalanges are the Flexor snblimis and profundus
digitorum ; the former flexing the second phalanges, and the latter the last.
The Flexor longus pollicis flexes the last phalanx of the thumb. The three
latter muscles, after flexing the phalanges, by continuing their action, act upon
the wrist, assisting the ordinary flexors of this joint; and all those which are
attached to the humerus assist in flexing the forearm upon the arm. The
Palmaris longus is a tensor of the palmar fascia ; when this action has been
fully effected, it flexes the hand upon the forearm.
Eadial Pegion. (Fig. 271.)
Supinator Longus. Extensor Carpi Eadialis Longior.
Extensor Carpi Eadialis Brevior.
Disisection. Divide the integument in the same manner as in the dissection of the anterior
brachial region ; and after having examined the cutaneous vessels and nerves and deep fascia,
remove all those structures. The muscles will then be exposed. The removal of the i'ascia will
be considerably facilitated by detaching it from below upwards. Great care should be taken to
avoid cutting across the tendons of the muscles of the thumb, which cross obliquely thft larger
tendons running down the back of the radius.
The Supinator Longus is the most superficial muscle on the radial side of the
forearm : it is fleshy for the upper two-thirds of its extent, tendinous below. It
arises from the upper two-thirds of the external condyloid ridge of the humerus,
and from the external intermuscular septum, being limited above by the musculo-
spiral groove. The fibres terminate above the middle of the forearm in a flat
tendon, which is inserted into the styloid process of the radius.
Relations. By its superficial surface, with the integument and fascia for the
greater part of its extent ; near its insertion it is crossed by the Extensor ossis
metacarpi pollicis and the Extensor primi internodii pollicis. By its deep surface,
with the humerus, the Extensor carpi radialis longior and brevior, the insertion
of the Pronator radii teres, and the Supinator brevis. By its inner harder, above
the elbow, with the Brachialis anticus, the musculo-spiral nerve, and radial
recurrent artery ; and in the forearm, with the radial vessels and nerve.
The Extensor Carpi Radialis Longior is placed partly beneath the preceding
muscle. It arises from the lower third of the external condyloid ridge of the
humerus, and from the external intermuscular septum. The fibres terminate at
the upper third of the forearm in a flat tendon, which runs along the outer
border of the radius, beneath the extensor tendons of the thumb ; it then passes
through a groove common to it and the Extensor carpi radialis brevior imme-
416
MUSCLES AND FASCIA.
Fig. 271. — Posterior Surface of the Forearm.
Superficial Muscles.
diately behind tlie styloid process ;
and is inserted into the base of the
metacarpal bone of the index finger,
on its radial side.
Relations. By its superficial sur-
face, with the Supinator longus, and
fascia of the forearm. Its outer side
is crossed obliquely by the extensor
tendons of the thumb. By its deejj
surface, with the elbow -joint, the
Extensor carpi radialis brevior, and
back part of the wrist.
The Extensor Cajjn Radialis
Brevier is shorter, as its name im-
plies, and thicker than the preceding
muscle, beneath which it is placed.
It arises from the external condyle
of the humerus by a tendon common
to it and the three following muscles;
from the external lateral ligament
of the elbow-joint ; from a strong
aponeurosis which covers its surface ;
and from the intermuscular septa
between it and the adjacent muscles.
The fibres terminate about the
middle of the forearm in a flat
tendon, which is closely connected
with that of the preceding muscle,
accompanies it to the wrist lying in
the same groove on the posterior
surface of the radius ; passes beneath
the annular ligament and, diverging
somewhat from its fellow, is inserted
into the base of the metacarpal bone
of the middle finoer on its radial
side.
The tendons of the two preceding
muscles pass through the same com-
partment of the annular ligament,
and are lubricated by a single syno-
vial membrane, but are separated
from each other by a small vertical
ridge of bone as they lie in the
groove at the back of the radius.
Relations. By its siiperficial sur-
face, with the Extensor carpi radialis
longior, and with the Extensor
muscles of the llmuib, which cross
it. By ils drcp surface, willi the
Sn})iiiat()r brcvis, tendon of the Pro-
nator radii teres, radius and wrist-
joint. By its ulnar horder, with the
Extensor communis digitorum.
Actions. The actions of the mus-
cles of this region will be described
in connecti(m with those of the pos-
terior brachial region.
POSTERIOR BRACHIAL REGION. 417
Posterior Brachial Eegion. (Fig. 271.)
Superficial Layer.
Extensor Communis Digitomm. Extensor Carpi Ulnaris.
Extensor Minimi Digiti. Anconeus.
Tlie Extensor Communis Digitorumj is situated at the back part of the forearm.
It arises from the external condyle of the humerus by the common tendon, from
the deep fascia, and the intermuscular septa between it and the adjacent muscles.
Just below the middle of the forearm it divides into three tendons, which pass,
together with the Extensor indicis, through a separate compartment of the
annular ligament, lubricated by a synovial membrane. The tendons then di-
verge, the innermost one dividing into two; and all, after passing across the
back of the hand, are inserted into the second and third phalanges of the fingers
in the following manner: Each tendon becomes narrow and thickened opposite
the metacarpo- phalangeal articulation, and gives off a thin fasciculus upon each
side of the joint which serves as the posterior ligament ; after having passed the
joint, it spreads out into a broad aponeurosis, which covers the whole of the
dorsal surface of the first phalanx ; being reinforced, in this situation, by the
tendons of the Interossei and Lumbricales. Opposite the first phalangeal joint
this aponeurosis divides into three slips, a middle, and two lateral: the former is
inserted into the base of the second phalanx ; and the two lateral, which are con-
tinued onwards along the sides of the second phalanx, unite by their contiguous
margins, and are inserted into the dorsal surface of the last phalanx. As the
tendons cross the phalangeal joints, they furnish them with posterior ligaments.
The tendons of the middle, ring, and little fingers are connected together, as they
cross the hand, by small oblique tendinous slips. The tendons of the index and
little fingers also receive,, before their division, the special extensor tendons
belonging to them.
Relations. By its superficial surface^ with the fascia of the forearm and hand,
the posterior annular ligament, and integument. By its dee^J surface^ with the
Supinator brevis, the Extensor muscles of the thumb and index finger, the pos-
terior interosseous vessels and nerve, the wrist-joint, carpus, metacarpus, and
phalanges. 'Qjil^ radial border^ with the Extensor carpi radius brevior. By its
ulnar border.^ with the Extensor minimi digiti, and Extensor carpi ulnaris.
The Extensor Minimi Digiti is a slender miiscle placed on the inner side of
the Extensor communis, with which it is generally connected. It arises from
the common tendon by a thin tendinous slip.; and from the intermuscular septa
between it and the adjacent muscles. Its tendon ru.ns through a separate com-
partment in the annular ligament behind the inferior radio-ulnar joint, then
divides into two as it crosses the hand, and, at the metacarpo- phalangeal articu-
lation, unites with the tendon derived- from the common Extensor, lying at first
to the ulnar side of that tendon and somewhat more superficial. The common
tendon then spreads into a broad aponeurosis, which is inserted into the second
and third phalanges of the little finger in a similar manner to the common ex-
tensor tendons of the other finarers.
The Extensor Carpi Ulnaris is the most superficial muscle on the ulnar side
of the forearm. It arises from the external condyle of the humerus, by the
common tendon ; from the middle third of the posterior border of the ulna below
the Anconeus, and from the fascia of the forearm. This muscle terminates in a
tendon, which runs through a groove behind the styloid process of the ulna,
passes through a separate compartment in the annular ligament, and is inserted
into the ulnar side of the base of the metacarpal bone of the little finger..
Relations. By its superficial surface.^ with the fascia of the forearm. By its
deep surface^ with the ulna, and the muscles of the deep layer.
The Anconeus is a small triangular muscle, placed behind and below the elbow
27
418 MUSCLES AND FASCIA.
joint, and appears to he a continuation of tlie external portion of the Triceps. It
arises bj a separate tendon from tlie back part of the outer condyle of the hume-
rus ; and is inserted into the side of the olecranon, and upper fourth of the poste-
rior surface of the shaft of the ulna ; its fibres diverge from their origin, the
upper ones being directed transversely, the lower obliquely inwards.
Belations. By its sxiferficial surface^ with a strong fascia derived from the Tri-
ceps. By itstZeep surface^ with the elbow-joint, the orbicular ligament, the ulna,
and a small portion of the Supinator brevis.
Posterior Brachial Eegion. (Fig. 272.)
Dee'p Layer.
Supinator Brevis. Extensor Primi Internodii Pollicis.
Extensor Ossis Metacarpi Pollicis, Extensor Secundi Internodii Pollicis.
Extensor Indicis.
The Supinator Brevis is a broad muscle, of a hollow cylindrical form, curved
round the upper third of the radius. It arises from the external condyle of the
humerus, from the external lateral ligament of the elbow -joint, and the orbicular
ligament of the radius, from the ridge on the ulna which runs obliquely down-
wards from the posterior extremity of the lesser sigmoid cavity, from the tri-
angular depression in front of it, and from a tendinous expansion which covers
the surface of the muscle. The muscle surrounds the upper part of the radius :
the upper fibres forming a sling-like fasciculus, which encircles the neck of the
radius above the tuberosity, and is attached to the back part of its inner surface ;
the middle fibres are attached to the outer edge of the bicipital tuberosity ; the
lower fibres to the oblique line of the radius, as low down as the insertion of the
Pronator radii teres. This muscle is pierced by the posterior interosseous nerve.
Relations. By its superficial surface^ with the superficial Extensor and Supi-
nator muscles, and the radial vessels and nerve. By its deep surface^ with the
elbow-joint, the interosseous membrane, and the radius.
The Extensor Ossis Metacarpi Pollicis is the most external and the largest of
the deep Extensor muscles : it lies immediately below the Supinator brevis, with
which it is sometimes united, it arises from the posterior surface of the shaft of
the ulna below the insertion of the Anconeus, from the interosseous ligament,
and from the middle third of the posterior surface of the shaft of the radius.
Passing obliquely downwards and outwards, it terminates in a tendon which runs
through a groove on the outer side of the styloid process of the radius, accom-
panied by the tendon of the Extensor primi internodii pollicis, and is inserted into
the base of the metacarpal bone of the thumb.
Relations. By its superficial surface^ with the Extensor communis digitorum,
Extensor minimi digiti, and fascia of the forearm ; and with the branches of the
posterior interosseous artery and nerve which cross it. By its deep surface^ with
the ulna, interosseous membrane, radius, the tendons of the Extensor carpi radi-
alis longior and brcvior, which it crosses obliquely ; and, at the outer side of the
wrist, with the radial vessels. By its upper border., with the Supinator brevis.
By its lower harder^ with the Extensor primi internodii pollicis.
The Extensor Primi Internodii Pollicis^ the smallest muscle of this group, lies
on the inner side of the preceding. It arises from the posterior surface of the
shaft of the radius, below the Extensor ossis metacarpi, and from the interosseous
membrane. Its direction is similar to that of the Extensor ossis metacarpi, its
tendrm passing tlirough llie same groove on the outer side of the styloid process
to bo inserted into tljcbasc of the first ])lialanx of thctluimb.
Rdaiions. Tlic same as those of the Extensor ossis metacarpi pollicis.
The Extensor Secundi hiternodii Pollicis is much larger than the ])reccding
muscle, the origin of which it partly covers in. It arises from llic jiosterior
surface of the shaft of the ulna, below the origin of llic Extensor ossis metacarpi
POSTERIOE BRACHIAL REGION.
419
pollicis, and from the interosseous membrane. It terminates in a tendon which,
passes through a separate compartment in the annular hgament, lying in a narrow
oblique groove at the back part
of the lower end of the radius.
It then crosses obliquely the
Extensor tendons of the carpus,
being separated from the other
Extensor tendons of the thumb
by a triangular interval, in which
the radial artery is found; and
is finally inserted into the base
of the last phalanx of the
thumb.
Relations. By its superficial
surface^ with the same parts as
the Extensor ossis metacarpi
pollicis. By its deep surface^
with the ulna, interosseous mem-
brane, radius, the wrist, the
radial vessels, and metacarpal
bone of the thumb.
The Extensor Indicis is a
narrow elongated muscle, placed
on the inner side of, and parallel
with, the preceding. It arises
from the posterior surface of the
shaft of the ulna, below the
origin of the Extensor secundi
internodii pollicis, and from the
interosseous membrane. Its ten-
don passes with the Extensor
communis digitorum through the
same canal in the annular liga-
ment, and subsequently joins
that tendon of the Extensor com-
munis which belongs to the index
finger, opposite the lower end
of the corresponding metacarpal
bone, lying to the ulnar side of
the tendon from the common
Extensor. It is finally inserted
into the second and third
phalanges of the index finger in
the manner already described.
Relations. They are similar
to those of the preceding mus-
cles.
Nerves. The Supinator longus,
Extensor carpi radialis longior,
and Anconeus, are supphed by
branches from the musculo-spiral
nerve. The remaining muscles
of the radial and posterior bra-
chial regions, by the posterior
interosseous nerve.
Actions. The muscles of the
Fig. 272. — Posterior Surface of the Forearm.
Muscles.
Deep
420
MUSCLES AND FASCIA.
radial and posterior bracliial regions, whicli comprise all tlie Extensor and
Supinator muscles, act upon tlie forearm, wrist, and hand; tliej are tlie direct
antagonists of the Pronator and Flexor muscles. The Anconeus assists the
Triceps in extending the forearm. The Supinator longus and brevis are the
supinators of the forearm and hand; the former muscle more especially acting
as a supinator when the limb is pronated. When supination has been produced,
the Supinator longus, if still continuing to act, flexes the forearm. The Extensor
carpi radialis longior and brevior, and Extensor carpi ulnaris muscles, are the
Extensors of the wrist ; continuing their action, thej serve to extend the forearm-
upon the arm ; thev are the direct antagonists of the Flexor carpi radialis and
ulnaris. The common Extensor of the fingers, the Extensors of the thumb, and
the Extensors of the index and little fingers, serve to extend the phalanges into
which they are inserted; and are the direct antagonists of the Flexors. By
continuing their action, they assist in extending the forearm. The Extensors
of the thumb, in consequence of the oblique direction of their tendons, assist in
supinating the forearm when the thumb has been drawn inwards towards the
palm.
Muscles and Fasci.^ of the Hand.
Dissection (Fig. 265). Make a transverse incision across the front of the wrist, and a second
across the heads of the metacarpal bones : connect the two by a vertical incision in the middle
line, and continue it throuch the centre of the middle finger. The anterior and posterior annular
ligaments, and the palmar fascia, should then be dissected.
The Anterior Annular Ligament is a strong fibrous band, which arches over
the carpus, converting the deep groove on the front of the carpal bones into a
canal, beneath which pass the flexor tendons of the fingers. It is attached,
internally, to the pisiform bone, and unciform process of the unciform bone;
and externally, to the tuberosity of the scaphoid, and ridge on the trapezium.
It is continuous, above, with the deep fascia of the forearm, and below, with the
palmar fascia. It is crossed by the ulnar vessels and nerve, and the cutaneous
branches of the median and ulnar nerves. It has inserted into its upper and
inner part the tendon of the Palmaris longus and part of the tendon of the
Flexor carpi ulnaris; and has, arising from it below, the small muscles of the
thumb and little finger. It is pierced by the tendon of the Flexor carpi radialis ;
and, beneath it, pass the tendons of
the Flexor sublimis and profundus
digitorum, the Flexor longus poUicis,
and the median nerve. There are
two synovial. membranes beneath this
ligament; one of large size, inclosing
the tendons of the Flexor sublimis
and profundus ; and a separate one
for the tendon of the Flexor longus
pollicis, which is also ver}^ extensive,
reaching from above the wrist to the
extremity of the last phalanx of the
thumb.
The Posterior AnnAilar Ligament is
a strong fibrous band, extending trans-
versely across the back of the wrist,
and continuous with the fascia of the
forearm. It forms a sheath for the
extensor tendons m their passage to the fingers, being attached, internally, to
llic ulna, the cuneiform and pisiform bones, and palmar fascia; externally, to the
margin of the radius: and, in its passage across the wrist, to the elevated ridges
on the posterior surface of the radius. It presents six compartments for the
passage of tendons, each of wliich is lined by a separate synovial membrane.
Fig. 27.3. — Transverse Section through the Wrist,
showing the Annular Ligaments and the Canals
for the Passage of the 'J'endons.
^ UONC p\^^CARpp^
■^'T. COM. Die
•-^T. IIIOICI'...
':sEc.\tn.^
OF THE HAND. 421
These are, from without inwards — 1. On the outer side of the styloid process
for the tendons of the Extensor ossis metacarpi, and Extensor primi internodii
polhcis. 2. Behind the styloid process, for the tendons of the Extensor carpi
radialis longior and brevior. 3. Opposite the outer side of the posterior surface
of the radius, for the tendon of the Extensor secundi internodii pollicis. 4. To
the inner side of the latter, for the tendons of the Extensor communis digitorum
and Extensor indicis. 5. For the Extensor minimi digiti, opposite the interval
between the radius and ulna. 6. For the tendon of the Extensor carpi ulnaris,
arroovino; the back of the ulna. The synovial membranes linino- these sheaths
are usually very extensive, reaching from above the annular ligament, down
upon the tendons almost to their insertion.
The palmar fascia forms a common sheath which invests the muscles of the
hand. It consists of a central and two lateral portions.
The central portion occupies the middle of the palm, is triangular in shape, of
great strength and thickness, and binds down the tendons in this situation. It
is narrow above, being attached to the lower margin of the annular ligament,
and receives the expanded tendon of the Palmaris longus muscle. Below, it is
broad and expanded, and opposite the- heads of the metacarpal bones divides
into four slips, for the four fingers. Each slip subdivides into two processes,
which inclose the tendons of the Flexor muscles, and are attached to the sides
of the first phalanx, and to the glenoid ligament : by this arrangement, four
arches are formed, under which the Flexor tendons pass. The intervals left in
the fascia, between the four fibrous slips, transmit the digital vessels and nerves,
and the tendons of the Lumbricales. At the points of division of the palmar
fascia into the slips above mentioned, numerous strong transverse fibres bind
the separate processes together. The palmar fascia is intimately adherent to
the integument by numerous fibrous bands, and gives origin by its inner margin
to the Palmaris brevis; it covers the superficial palmar arch, the tendons of the
flexor muscles, and the branches of the median and ulnar nerves ; and on each
side it gives off a vertical septum, which is continuous with the interosseous
aponeurosis, and separates the lateral from the middle palmar group of muscles.
The lateral portions of the palmar fascia are thin fibrous layers, which cover,
on the radial side, the muscles of the ball of the thumb ; and, on the ulnar side,
the muscles of the little finger ; they are continuous with the dorsal fascia, and
in the palm with the middle portion of the palmar fascia.
Muscles of the Hand.
The Muscles of the Hand are subdivided into three groups:—!. Those of the
thumb, which occupy the radial side. 2. Those of the little finger, which occupy
the ulnar side. 3. Tliose in the middle of the palm and between the interosseous
spaces.
Radial Region. (Fig. 274.)
Muscles of the Thumb.
Abductor Pollicis.
Opponens Pollicis (Flexor Ossis Metacarpi).
Flexor Brevis Pollicis.
Adductor Pollicis.
The Ahductor Pollicis is a thin flat muscle, placed immediately beneath the
integument. It arises from the ridge of the os trapezium and annular ligament;
and, passing outwards and downwards, is inserted bv a thin flat tendon into the
radial side of the base of the first phalanx of the thumb.
Relations. By its superficial surface, with the palmar fascia. Bv its deep
surface, with the Opponens pollicis, from which it is separated bv a thin aponeu-
rosis. Its inner border is separated from the Flexor brevis pollicis by a narrow
cellular interval.
422
MUSCLES AND FASCIA.
The Ojpjponeris Pollicis is a small triangular muscle, placed beneatli the pre-
ceding. It arises from the palmar surface of the trapezium and annular ligament,
passes downwards and outwards, and is inserted into the whole length of the
metacarpal bone of the thumb on its radial side.
Fig. 274. — Muscles of the Left Hand. Palmar Surface.
Relations. By its superficial surfnce, with tlio Alxluctor pollicis. By its deep
surface, with the trapezio-metacarpal articulation. By its inner border, with the
Flexor brevis pollicis.
The Flexor Brevis Pollicis is much larger than citlior of the two preceding
muscles, beneath which it is placed. It consists of two portions, in the interval
OF THE HAND. 423
between wliicli lies tlie tendon of the Flexor longus poUicis. The anterior and
more superficial portion arises from the trapezium and outer two-thirds of the
annular ligament ; the deeper portion from the trapezoid, os magnum, base of
the third metacarpal bone, and sheath of the tendon of the Flexor carpi radialis.
The fleshy fibres imite to form a single muscle ; this divides into two portions,
which are inserted one on either side of the base of the first phalanx of the
thumb, the outer portion being joined with the Abductor, and the inner with
the Adductor. A sesamoid bone is developed in each tendon as it passes across
the metacarpo-phalangeal joint.
Relations. Bj its superficial surface., with the palmar fascia. By its deep
surface., with the Adductor poUicis, and tendon of the Flexor carpi radialis. By
its external surface., with the Opponens poUicis. By its internal surface., with
the tendon of the Flexor longus poUicis.
The Adductor PoUicis (Fig. 270) is the most deeply-seated of this group of
muscles. It is of a triangular form, arising, by its broad base, from the whole
length of the metacarpal bone of the middle finger on its palmar surface ; the
fibres, proceeding outwards, converge, to be inserted with the inner tendon of
the Flexor brevis poUicis, into the ulnar side of the base of the first phalanx of
the tliumb, and into the internal sesamoid bone.
Relations. By its superficial surface., with the Flexor brevis poUicis, the ten-
dons of the Flexor profundus and the Lumbricales. Its deep surface covers the
first two interosseous spaces, from which it is separated by a strong aponeurosis.
Nerves. The Abductor, Opponens, and outer head of the Flexor brevis pol-
licis, are supplied by the median nerve; the inner head of the Flexor brevis,
and the Adductor poUicis, by the ulnar nerve.
Actions. The actions of the muscles of the thumb are almost sufficiently
indicated by their names. This segment of the hand is provided with three
Extensors — an Extensor of the metacarpal bone, an Extensor of the first, and
an Extensor of the second phalanx; these occupy the dorsal surface of the
forearm and hand. There are, also, three flexors on the palmar surface — a
Flexor of the metacarpal bone, the Flexor ossis metacarpi (Opponens poUicis),
the Flexor brevis poUicis, and the Flexor longus poUicis; there is also an
Abductor and an Adductor. These muscles give to the thumb its extensive
range of motion.
Uliv^ar Eegion. (Fig. 27-1.)
Muscles of the Little Finger.
Palmaris Brevis. Flexor Brevis Minimi Digiti.
Abductor Minimi Digiti. OpjDonens Minimi Digiti (Flexor Ossis Metacarpi).
The Palmaris Brevis is a thin quadrilateral muscle, placed beneath the integu-
ment on the ulnar side of the hand. It arises by tendinous fasciculi, from the
annular ligament and palmar fascia ; the fleshy fibres pass horizontally inwards
to be inserted into the skin on the inner border of the palm of the hand.
Relations. By its superficial surface., with the integument to which it is inti-
mately adherent, especially by its inner extremity. By its deep surface., with
the inner portion of the palmar fascia ; which separates it from the ulnar vessels
and nerve, and from the muscles of the ulnar side of the hand.
The Abductor Minimi Digiti is situated on the ulnar border of the palm of
the hand. It arises from the pisiform bone, and from an expansion of the
tendon of the Flexor carpi ulnaris; and terminates in a flat tendon, which is
inserted into the ulnar side of the base of the first phalanx of the little finger.
Relations. By its superficial surface., with the inner portion of the palmar
fascia, and the Palmaris brevis. By its deep surface^ with the Flexor ossis meta-
carpi. By its inner harder., with the Flexor brevis minimi digiti.
The Flexor Brevis Minimd Digiti lies on the same plane as the preceding
muscle, on its radial side. It arises from the tip of the unciform process of the
424
MUSCLES AND FASCIA.
unciform bone, and anterior surface of tlie annular ligament, and is inserted into
tlie base of tlie first phalanx of the little finger, with the preceding. It is sepa-
rated from the Abductor at its origin, by the deep branches of the ulnar artery
and nerve. This muscle is sometimes wanting; the Abductor is then, usually,
of large size.
Belations. By its suj)erficial surface^ with the internal portion of the palmar
fascia, and the Palmaris brevis. By its deep surface^ with the Opponens.
The Opponens Minimi Digiii (Fig. 270) is of a triangular form, and placed
immediately beneath the preceding muscles. It arises from the unciform process
of the unciform bone, and contiguous portion of the annular ligament; its fibres
pass downwards and inwards, to be inserted into the whole length of the meta-
carpal bone of the little finger, along its ulnar margin.
Relations. By its superficial surface^ with the Flexor brevis, and Abductor
minimi digiti. By its deep surface.^ with the Interossei muscles in the fourth
metacarpal space, the metacarpal bone, and the Flexor tendons of the little
finger.
Nerves. All the muscles of this group are supplied by the ulnar nerve.
Actions. The actions of the muscles of the little finger are expressed in their
names. The Palmaris brevis corrugates the skin on the inner side of the palm
of the hand.
Fie
27.5. — The Dorsal Interossei of
Left Ha!id.
Middle Palmak PtEGioN.
Lumbricales. Interossei Palmares.
Interossei Dorsales.
The Lumhricales (Fig. 274) are four small fleshy fasciculi, accessories to the
deep Flexor muscle. They arise by fleshy fibres from the tendons of the deep
Flexor: the first and second, from the
radial side and palmar surface of the tendons
of the index and middle fingers ; the third,
from the contiguous sides of the tendons
of the middle and ring fingers ; and the
fourth, from the contiguous sides of the
tendons of the ring and little fingers. They
pass forwards to the radial side of the
corresponding fingers, and opposite the
metacarpo-phalangeal articulation each ten-
don terminates in a broad aponeurosis,
which is inserted into the tendinous expan-
sion from the Extensor communis digi-
torum, covering the dorsal aspect of each
finger.
The Interossei Muscles are so named from
occupying the intervals between the meta-
carpal bones. They arc divided into two
sets, a dorsal and palmar; the former arc
four in number, one in each metacarpal
space ; the latter, three in number, lie upon
the metacarpal bones.
The Dorsal Tnterossei arc four in number,
larger llian the palmar, and occupy the
intervals between the metacarpal bones.
They arc bipcnnin^rm muscles, arising by two heads from the adjacent sides of
the metacarpal b(;ncs, but more extensively from that side of the metacarpal
hone which corresponds to the side of the finger in which the muscle is inserted.
They are inserted into the base of tlic first phalanges and into the aponeurosis
of the common Extensor leiidon. Between the doid^le ori'dn of each of these
OF THE HAND.
425
Fig. 276. — The Palmar Interossei
of Left Haod.
muscles is a narrow triangular interval, through wliicli passes a perforating
branch from the deep palmar arch.
The First Dorsal Interosseous muscle, or Abductor indicis, is larger than the
others. It is flat, triangular in form, and arises bj two heads, separated by a
fibrous arch, for the passage of the radial artery from the dorsum to the palm
of the hand. The outer head arises from the upper half of the ulnar border of
the first metacarpal bone ; the inner head, from almost the entire length of the
radial border of the second metacarpal bone; the tendon is inserted into the
radial side of the index finger. The second and third dorsal interossei are
inserted into the middle finger, the former into its radial, the latter into its
ulnar side. The fourth is inserted into the ulnar side of the ring finger.
The Palmar Interossei^ three in number, are smaller than the Dorsal, and
placed upon the palmar surface of the metacarpal bones, rather than between
them. They arise from the entire length of the
metacarpal bone of one finger, and are inserted
into the side of the base of the first phalanx and
aponeurotic expansion of the common Extensor
tendon of the same finger.
The first arises from the ulnar side of the
second metacarpal bone, and is inserted into the
same side of the index finger. The second arises
from the radial side of the fourth metacarpal
bone, and is inserted into the same side of the
ring finger. The third arises from the radial
side of the fifth metacarpal bone, and is inserted
into the same side of the little finger. From
this account it may be seen, that each finger is
provided with two Interossei muscles, with the
exception of the little finger, in which the Ab-
ductor muscle takes the place of one of the pair.
Nerves. The two outer Lumbricales are sup-
plied by the median nerve ; the rest of the mus-
cles of this group, by the ulnar.
Actions. The Dorsal interossei muscles abduct
the fingers from an imaginary line drawn longi-
tudinally through the centre of the middle fin-
ger; and the Palmar interossei adduct the fingers
towards that line. They usually assist the Ex-
tensor muscles ; but when the fingers are slightly
bent, they assist in flexing them. The action of the Lumbricales and Internal
or Dorsal interossei is said by Hunter to be to flex the first phalanges, and
extend the last two (works by Palmer, iv. 237); and Cleland supports this
(" Journ. of Anat. and Phys.," Old series, i. 85). M. Duchenne gives a difierent
account of the mechanism of the extension of the fingers and of the action of
the Interossei muscles from that usually accepted. According to him, the
Extensor communis digitorum acts almost entirely on the first phalanges, ex-
tension of the second and third phalanges being efiected by the Interossei
muscles, which also act to a certain extent as flexors of the first phalanges.
This action of the Interossei is additional to their action in abduction and
adduction ("Physiologic des Mouvements," pp. 261-298).^
' M. Dnchenne's view of the action of these muscles certainly derives support from the phe-
nomena observed in lead-palsy and from the results of galvanizing the common Extensor and
the Interossei, as Dr. W. Ogle has been kind enough to point out to me. Thus also in a case
related by Mr. Hutchinson, in which the ulnar nerve had been divided below the part from which
the Extensor communis was supplied (and therefore the Interossei were paralyzed while the
Extensor acted), "the first phalanges were bent backwards on the metacarpal bones" (extended)
" while the fingers were curved into the palm" (second and third phalanges flexed). London
Hospital Reports, vol. iii. p. 307.
426
SUEGICAL ANATOMY.
SURGICAL AT^ATOMY.
Fig. 277.— Fracture of the Middle of
tlie Clavicle.
The Student, having completed the dissection of the muscles of the upper extremit}-. should con-
sider the effects likely to be produced by the action of the various muscles in fracture of the bones.
In considering the actions of the various muscles upon fractures of the upper extremity, I have
selected the most common forms of injury, both for illustration and description.
Fracture of the clavicle is an exceedingly common accident, and is usually caused by indirect
violence, as a fall upon the shoulder ; it occasionally, however, occurs from direct force. Its
more usual situation is just external to the centre of the bone, but it may occur at the sternal
or acromial end.
Fracture of the middle of the clavicle (Fig. 277) is always attended with considerable displace-
ment, the outer fragment being drawn downwards, forwards, and inwards; the inner fragment
slightly upw'ards. The outer fragment is drawn down
by the weight of the arm, and the action of the Deltoid,
and forwards and inwards by tlie Pectoralis minor and
Subclavius muscles : the inner fragment is slightly raised
by the Sterno cleido mastoid, but only to a very limited
extent, as the attachment of the costo-clavicular ligament
and Pectoralis major below and in front would prevent
any very great displacement upwards. The causes of
displacement having been ascertained, it is easy to apply
the appropriate treatment. 'J'he outer fragment is to be
drawn outwards, and together with the scapula, raised
upwards to a level with the inner fragment, and retained
in that position.
In fracture of the acromial end of the clavicle, between
the conoid and trapezoid ligaments, only slight displace-
ment occurs, as these ligaments, from their oblique inser-
tion, serve to hold both portions of the bone in apposition.
Fracture, also, of the sterncd end, internal to the costo-
clavicular ligament, is attended with only slight displace-
ment, this ligament serving to retain the fragments in
close apposition.
Fracture of the acromion process usually arises from
violence applied to the upper and outer part of the
shoulder; it is generally known by the rotundity of the
shoulder being lost, from the Deltoid drawing the fr.ac-
tured portion downwards and forwards ; and the displace-
ment may easily be discovered by tracing the margin of
the clavicle outwards, when the fragment will be found
resting on the front and upper part: of the head of the
humerus. In order to relax the anterior and outer fibres
of the Deltoid (the opposing muscle), the arm should be drawn forwards across the ciiest, and the
elbow well raised, so that the head of the bone may press the acromion process upwards and retain
it in its position.
Fracture of the coracotd process is an extremely rare accident, and is usually caused by a sharp
blow ou the point of the shoulder. Displacement is here produced by the combined actions of the
Pectoralis minor, short head of the Biceps, and Coraco-bra-
chialis, the former muscle drawing the fragment inwards, and
the latter directly downwards, the amount of displacement
being limited by the connection of this process to the acromion
by means of the coraco-acromial ligament. In order to relax
these muscles and replace the fragments in close apposition,
till' forearm should be flexed so as to relax the Biceps, and the
arm drawn forwards and inwards across the chest so as to relax
111!' (Joraco-bracliialis; the humerus should then be pushed
upwards against the coraco-acromial ligament, and the arm
retained in that position.
Fracture of the avalomiccd neck of the hnmertis within the
capsular ligament is a rare accident, attended with very slight
displacement, an impaired condition of the motions of the joint,
and crepitus.
Fracture of the snrf)ica,l veclc (Fig. 278) is very common, is
attended with coiisiderai)le disi)lacemeiit, and its appearances
correspond somewhat with those of dislocation of the head of
the linmerus into the axilla. Tlu! upper fragment is slightly
elevated under the coraco-acromial ligament by the muscles
attached to the greater and lesser tuberosities; the lower frag-
ment is drawn inwiirds liy the I'ectoralis major, Latissimus
Fig. 278.— Fracture of the Sur-
gical Neck of the Humerus.
\^
FRACTURES OF THE UPPER EXTREMITY.
427
Fig. 279. — Fracture of the Humerus
above the Coudyles.
dorsi, and Teres major; and the humerus is thrown obliquely outwards from the side by the Del-
toid, and occasionally elevated so as to project beneath and in front of the coracoid process. The
deformity is reduced by fixing the shoulder, and drawing the arm outwards and downwards. To
counteract the opposing muscles, and to keep the fragments in position, the arm should be drawn
from the side, and pasteboard splints applied on its four sides, a large conical-shaped pad should
be placed in the axilla with the base turned upwards, and the elbow approximated to the side,
and retained there by a broad roller passed round the chest; the forearm should then be flexed,
and the hand supported in a sling, care being taken not to raise the elbow, otherwise the lower
fragment may be displaced upwards.
In fracture of the sliaft of the humerus below the insertion of the Pectoralis major, Latissimus
dorsi, and Teres major, and above the insertion of the Deltoid, there is also considerable deformity,
the upper fragment being drawn inwards by the first-mentioned muscles, and the lower fragment
upwards and outwards by the Deltoid, producing shortening of the limb, and a considerable
prominence at the seat of fracture, from the fractured ends of the bone riding over one another,
especially if the fracture takes place in an oblique direction.
The fragments maybe brought into apposition by extension
from the elbow, and retained in that position by adopting
the same means as in the preceding injury.
In fractures of the shaft of the humerus immediately
below the insertion of the Deltoid the amount of deformity
depends greatly upon the direction of the fracture. If the
fracture occurs in a transverse direction, only slight displace-
ment occurs, the upper fragment being drawn a little for-
wards ; but in oblique fracture, the combined actions of the
Biceps and Brachialis anticus muscles in front, and the Tri-
ceps behind, draw upwards the lower fragment, causing it
to glide over the upper fragment, either backwards or for-
wards, according to the direction of the fracture. Simple
extension reduces the deformity, and the application of
splints on the four sides of the arm will retain the fragments
in apposition. Care should be taken not to raise the elbow;
but the forearm and hand may be supported in a sling.
Fracture of the humerus (Fig. 279) immediately above
the condyles deserves very attentive consideration, as the
general appearances correspond somewhat with those pro-
duced by separation of the epiphysis of the humerus, and
with those of dislocation of the radius and ulna backwards.
If the direction of the fracture is oblique from above, down-
wards, and forwards, the lower fragment is drawn upwards
and backwards by the Brachialis anticus and Biceps in front,
and the Triceps behind. This injury may be diagnosed from
dislocation, by the increased mobility in fracture, the existence of crepitus, and the fact of the
deformity being remedied by extension, on the discontinuance of which it is reproduced. The
age of the patient is of importance in distinguishing this form of injury from separation of the
epiphysis. If fracture occurs in the opposite
Fig, 280. — Fracture of the Olecranon.
direction to that shown in the accompanying
figure, the lower fragment is drawn upwards and
forwards, causing a considerable prominence in
front ; and the upper fragment projects back-
wards beneath the tendon of the Triceps muscle.
Fracture of the coronoid process of the tdna
is an accident of rare occurrence, and is usually
caused by violent action of the Brachialis anti-
cus muscle. The amount of displacement varies
according to the extent of the fracture. If the
tip of the process only is broken off, the frag-
ment is drawn upwards by the Brachialis anticus
on a level with the coronoid depression of the
humerus, and the power of flexion is partially
lost. If the process is broken off near its root,
the fragment is still displaced by the same
muscle ; at the same time, on extending the
forearm, partial dislocation backwards of the
ulna occurs from the action of the 'I'riceps
muscle. The appropriate treatment would be
to relax the Brachialis anticus by flexing the
forearm, and to retain the fragments in apposition by keeping the arm in this position,
is generally ligamentous. ,
Fracture of the olecranon process (Fig. 280) is a more frequent accident, and is caused either
by violent action of the Triceps muscle, or by a fall or blow upon the point of the elbow. Tlie
Union
428
SURGICAL ANATOMY
detached fragment is displaced upwards, by the action of the Triceps muscle, from half an inch
to two inches ; the prominence of the elbow is consequently lost, and a deep hollow is felt at the
back part of the joint, which is much increased on flexing the limb. The patient at the same
time loses, more or less, the power of extending the forearm. The treatment consists in relaxing
the Triceps by extending the limb, and retaining it in the extended position by means of a long
straight splint applied to the front of the arm ; the fragments are thus brought into close apposi-
tion, and may be further approximated by drawing down the upper fragment. Union is generally
ligamentous.
Fracture of the neck of the radius is an exceedingly rare accident, and is generally caused by
direct violence. Its diagnosis is somewhat obscure, on account of the slight deformity visible :
the injured part being surrounded by a large number of muscles; but the movements of pronation
and supination are entirely lost. The upper fragment is drawn outwards by the Supinator brevis,
its extent of displacement being limited by the attachment of the orbicular ligament. The lower
fragment is drawn forwards and slightly upwards by the Biceps, and inwards by the Pronator
radii teres, its displacement forwards and upwards being counteracted in some degree by the
Supinator brevis. The treatment essentipJly consists in relaxing the Biceps, Supinator brevis,
and Pronator radii teres muscles, by flexing the forearm, and placing it in a position midway
between pronation and supination, extension having been previously made so as to bring the parts
in apposition.
Fracture of the radius (Fig. 281) is more common than fracture of the ulna, ou account of the
connection of the former bone with the wrist. Fracture of the shaft of the radius near its centre
may occur from direct violence, but more fre-
Fi,!2:. 281. — Fracture of the Shaft of the Radius, quently from a fall forwards, the weight of the
body being received ou the wrist and hand. The
upper fragment is drawn upwards by the Biceps,
and inwards by the Pronator radii teres, holding
a position midway between pronation and supi-
nation, and a degree of fulness in the upper half
of the forearm is thus produced : the lower frag-
ment is drawn downwards and inwards towards
the ulna by the Pronator quadratus, and thrown
into a state of pronation by the same muscle ;
at the same time, the vSupinator longus, by
elevating the styloid process, into which it is
inserted, will serve to depress the upper end of
the lower fragment still more towards the ulna. In order to relax the opposing muscle the forearm
should be bent, and the limb placed in a position midw'ay between pronation and supination ; the
fracture is then easily reduced by ext^ision from the wrist and elbow : well-padded splints should
then be applied on both sides of the forearm from the elbow to the wrist ; the hand being allowed
to fall, will, by its own weight, counteract the action of the Pronator quadratus and Supinator
longus, and elevate the lower fragment to the level of the upper one.
Fracture of the shaft of the idna is not a conmion accident; it is usually caused by direct
violence. The more protected position of the ulna on the inner side of the limb, the greater
strength of its shaft, and its indirect connection with the wrist, render it less liable to injury than
the radius. The fracture usually occurs a little below the middle, which is the weakest part of
the bone. The upper fragment retains its usual position, but the lower fragment is drawn out-
wards towards the radius by the Pronator quadratus, producing a well-marked depression at the
seat of fracture, and some fulness on the dorsal and palmar surfaces of the forearm, 'i'he fracture
is easily reduced by extension from the wrist and forearm. 'J'he forearm should be flexed, and
placed in a position midway between pronation and supination, and well-padded splints applied
irom the elljow to the ends of the fingers.
Fracture of the shafts of the radius and idna together is not a very common accident; it may
arise from a direct blow, or from indirect violence. The lower fragments are drawn upwards,
sometimes forwards, sometimes backwards, according to the direction of the fracture, by the com-
bined actions of the Flexor and E.xtensor muscles, producing a degree of fulness on the dorsal
or f)almar surface of the forearm ; at the same time the two fragments are drawn into contact by
llie Pronator quadratus, the radius in a state of pronation : the upper fragment of the radius is
drawn upwards and inwards l)y the Biceps and Pronator radii teres to a higher level than tlie~
ulna; the upper portion of the ulna is slightly elevated l)y the Brachialis anticus. 'I'lie fracture
may be reduced by extension from the wrist and eli)ow, and the forearm should be jjlaced in the
same position as in fracture of the ulna.
In the treatment of all cases of fracture of the bones of the forearm, the greatest care is requisite
to prevent tlie ends of the l)ones from Ix'iiig drawn inwards towards the interosseous space: if this
point is not carefidly attended to, IIk* radius and ulna may becume anchylosiMl, and the movements
of promilioh and snpimition entirely lost. 'I\) obviate this, the splints iipplied to the limb shouhl
})C well iiadded. HO as to jiress the. muscles down into their noruial situation in the interosseous
j*paco. and thus prevent th(! a])pr(».\imalion of the fragments.
Fracture of IIk; lovu-r mil nf the radius (Fig. 282) is usually <;alled Collcs's fracture, from the
name of the eminent Duldin surgeon who first a<'cnrately des(ril)e it. It is geiu'rally produced
by the patient falling upon the hand, which receives the entire weight of the body. This fracture
MUSCLES AND FASCIA OF THE LOWER EXTREMITY. 429
usually takes place from half an inch to an inch above the articular surface if it occurs in the
adult ; but in the child, before the age of sixteen, it is more frequently a separation of the epiphysis
from the diaphysis. The displacement which is produced is very considerable, and bears some
resemblance to dislocation of the carpus backwards, from which it should be carefully distinguished.
The lower fragment is drawn upwards and backwards behind the upper fragment by the combined
Fig. 282. — Fracture of the Lower End of the Radius.
actions of the Supinator longus and the flexors and the extensors of the thumb and carpus, pro-
ducing a well-marked prominence on the back of the wrist, with a deep depression above it. The
upper fragment projects forwards, often lacerating the substance of the Pronator quadratus, and
is drawn by this muscle into close contact with the lower end of the ulna, causing a projection on
the anterior surface of the forearm, immediately above the carpus, from the flexor tendons being-
thrust forwards. This fracture may be distinguished from dislocation by the deformity being
removed on making sufBcient extension, when crepitus may be occasionally detected; at the same
time, on extension being discontinued, the parts immediately resume their deformed appearance.
The age of the patient will also assist in determining whether the injury is fracture or separation
of the epiphysis. The treatment consists in flexing the forearm, and making powerful extension
from the wrist and elbow, depressing at the same time the radial side of the hand, and retaining
the parts in that position by well-padded pistol-shaped splints.
MUSCLES AND FASCIiE OF THE LOWER EXTREMITY.
The Muscles of the Lower Extremity are subdivided into groups, corre-
sponding with the different regions of the limb.
Hip.
Iliac Region. Gluteal Region.
Psoas magnns.
Psoas parvus.
Illiacns.
Thigh.
Anterior Femoral Region.
Tensor vaginse femoris.
Sartorius,
Rectus.
Vastus externus.
Vastus internus.
Crurens.
Subcrureus.
Internal Femoral Region.
Gracilis.
Pectineus.
Adductor longus.
Adductor brevis.
Adductor mas;nus.
Gluteus maximns.
Gluteu.s medius.
Gluteus miniiuus.
Pj^riformis.
Gemellus superior.
Obturator internus.
Gemellus inferior.
Obturator externus.
Quadratus femoris.
Posterior Femoral Region.
Biceps.
Semitendinosus.
Semimembranosus.
Leg-.
Anterior Tihio-filmlar Region.
Tibialis anticus.
Extensor proprius pollicis.
Extensor longus digitorum.
Peroneus tertius.
430
MUSCLES AND FASCIA.
Posterior Tihio-fihular Region.
Superficial Layer.
Gastrocnemius.
Plantaris.
Soleus.
Deep Layer.
PopliteiTS.
Flexor longus pollicis.
Flexor longus digitorum.
Tibialis posticus.
Fihular Region.
Peroneus longus.
Peroneus brevis.
Foot.
Dorsal Region.
Extensor brevis digitorum.
Plantar Region.
First Layer.
Abductor pollicis.
Flexor brevis digitorum.
Abductor minimi digiti.
Second Layer.
Flexor accessorius.
Lumbricales.
Third Layer.
Flexor brevis pollicis.
Adductor pollicis.
Flexor brevis minimi digiti.
Transversus j)edis.
Fourth Layer.
The Interossei.
Psoas Ma2;nus.
Iliac Eegion".
Psoas Parvus.
Iliacus.
Dissection. No detailed description is required for the dissection of these muscles. On the
removal of the viscera from the abdomen, they are exposed, covei'ed by the peritoneum and a
thin layer of fascia, the fascia iliaca.
The Iliac fascia is the aponeurotic layer which lines the back part of the
abdominal cavity, and covers the Psoas and Iliacus muscles throughout their
whole extent. It is thin above ; and becomes gradually thicker below, as it
approaches the femoral arch.
The portion investing the Psoas is attached, above, to the ligamentum arcuatum
internum ; internally, to the sacrum ; and by a series of arched processes to the
intervertebral substances, and prominent margins of the bodies of the vertebrse;
the intervals so left, opposite the constricted portions of the bodies, transmitting
the lumbar arteries and filaments of the sympathetic nerve. Externally, this
portion of the iliac fascia is continuous with the fascia lumborum.
The portion investing the Iliacus is connected, externally, to the whole length
of the inner border of the crest of the ilium; and internally to the brim of the
true pelvis, where it is continuous with the periosteum, and receives the tendon
of insertion of the Psoas parvus, when that muscle exists. External to the
femoral vessels, this fascia is intimately connected with Poupart's ligament, and
is continuous with the fascia transvcrsalis ; but, as the femoral vessels pass down
into the thigh, it is prolonged down behind them, forming the posterior wall of
the fcmoriil sheath. Outside the femoral sheath, the iliac fascia surrounds the
Psf^as and Iliacus muscles to their termination, and becomes continuous with the
iliac portion of the fascia lata. Internal to the femoral vessels, the iliac fascia
is connected to the ilio-pectincal line, and is continuous with the pubic portion
of the fascia lata. The external iliac vessels lie in front of the iliac fascia, but
all the branches of the lumbar plexus behind it; it is separated from the perito-
neum by a rpiantity of loose areolar tissue. In abscess accompanying caries of
tlic lower ])art of tlic spine, tlie matter makes its way to the femoral arch, dis-
tending tlie^ sheath of the Psoas; and when it accumulates in considerable
quantity, tliis muscle becomes absorbed, ami the nervous cords contained in it
arc dissected out, and arc exposed in tlic cavity of tlie abscess; the femoral
vessels, however, remain intact, and the peritoneum seldom becomes implicated.
(Remove this fascia, and the muscles of the iliac region will be exposed.)
OF THE LOWER EXTREMITY. 431
The Psoas Magnus (Fig. 284) is a long fusiform muscle, placed on the side of
the lumbar region of the spine and margin of the pelvis. It arises from the sides
of the bodies, from the corresponding intervertebral substances, and from the
front of the bases of the transverse processes of the last dorsal and all the
lumbar vertebrge. The muscle is connected to the bodies of the vertebrae by five
slips ; each slip is attached to the upper and lower margins of two vertebrae and
to the intervertebral substance between them ; the slips themselves being con-
nected by the tendinous arches which extend across the constricted part of the
bodies, and beneath which pass the lumbar arteries and sympathetic nerves.
These tendinous arches also give origin to muscular fibres, and protect the blood-
vessels and nerves from pressure during the action of the muscle. The first slip
is attached to the contiguous margins of the last dorsal and first lumbar verte-
brae ; the last to the contiguous margins of the fourth and fifth lumbar, and to
the intervertebral substance. From these points the muscle passes down across
the brim of the pelvis, and, diminishing gradually in size, passes behind Poupart's
ligament, and terminates in a tendon, which, after receiving the fibres of the
Iliacus, is inserted into the lesser trochanter of the femur.
Relations. In the lumbar region. By its anterior surface^ which is placed
behind the peritoneum, with the iliac fascia, the ligamentum arcuatum internum,
the kidney. Psoas parvus, renal vessels, ureter, spermatic vessels, genito-crural
nerve, the colon, and along its pelvic border, with the common and external
iliac artery and vein. By its -posterior surface^ with the transverse processes of
the lumbar vertebrje, and the Quadratus lumborum, from which it is separated
by the anterior lamella of the aponeurosis of the Transversalis. The anterior
crural nerve is at first situated in the substance of the muscle, and emerges from
its outer border at the lower part. The lumbar plexus is situated in the poste-
rior part of the substance of the mu.scle. By its inner side^ the muscle is in
relation with the bodies of the lumbar vertebrae, the lumbar arteries, the ganglia
of the sympathetic nerve, and their branches of communication with the spinal
nerves ; the lumbar glands ; the vena cava inferior on the right, and the aorta
on the left side. In the thigh it is in relation, in front, with the fascia lata ;
behind, with the capsular ligament of the hip, from which it is separated by a
synovial bursa, which sometimes? communicates with the cavity of the joint
through an opening of variable size ; by its inner horder^ with the Pectineus and
the femoral artery, which slightly overlaps it ; by its outer border^ with the
anterior crural nerve and Iliacus muscle.
The Psoas Parvus is a long slender muscle, placed in front of the preceding.
It arises from the sides of the bodies of the last dorsal and first lumbar verte-
brae and from the intervertebral substance between them. It forms a small flat
muscular bundle, which terminates in a long flat tendon, inserted into the ilio-
pectineal eminence, and continuous, by its outer border, with the iliac fascia.
This muscle is present, according to M. Theile, in one out of every twenty sub-
jects examined.
Relations. It is covered by the peritoneum, and at its origin by the liga-
mentum arcuatum internum ; it rests on the Psoas magnus.
The Iliacus is a flat radiated muscle, which fills up the whole of the internal
iliac fossa. It arises from the iliac fossa, and inner margin of the crest of the
ilium ; behind, from the ilio-lumbar ligament, and base of the sacrum ; in front,
from the anterior superior and anterior inferior spinous processes of the ilium,
from the notch between them, and by a few fibres from the capsule of the hip-
joint. The fibres converge to be inserted into the outer side of the tendon of
the Psoas, some of them being prolonged into the oblique line which extends
from the lesser trochanter to the linea aspera.
Relations. Within the Pelvis: hj its anterior surface^ with the iliac fascia which
separates the muscle from the peritoneum, and with the external cutaneous
nerve ; on the right side, with the caecum ; on the left side, with the sigmoid
flexure of the colon. By its p)osterior surface^ with the iliac fossa. By its inner
432
MUSCLES AND FASCIA,
harder^ witli the Psoas magnus, and anterior crural nerve. In tlie tliigli, it is in
relation, by its anterior surface^ witli the fascia lata, Eectus and Sartorius ; behind,
with the capsule of the hip-joint, a synovial bursa common to it and the Psoas
magnus being interposed.
Nerves. The Psoas is supplied by the anterior branches of the lumbar nerves,
the Iliacus by the anterior crural.
Actions. The Psoas and Iliacus muscles, acting from above, flex the thigh
upon the pelvis, and, at the same time, rotate the femur outwards, from the
'obliquity of their insertion into the inner and back part of that bone. Acting
from below, the femur being fixed, the muscles of both sides bend the lumbar
portion of the spine and pelvis forwards. They also serve to maintain the erect
position, by supporting the spine and pelvis upon the femur, and assist in raising
the trunk when the body is in the recumbent posture.
The Psoas parvus is a tensor of the iliac fascia.
Anterior Femoral Eegion.
Tensor Yaginse Femoris.
Sartorius.
Eectus.
Subcrureus.
Vastus Externus.
Vastus Internus.
Crureus.
Fig. 283. — Dissection of Lower Ex-
tremity. Front View,
/ . Dc'Sseefian
"f
\ FEMORAL her;
I Sr,
Scarpa's Ti^iawcls
A,
Dissection. To expose the muscles and fasci?e in
this region, make an incision along Ponpart's liga-
ment, from the spine of the ilium to the pubes. a
vertical incision from the centre of this, along the
middle of the thigh to below the knee-joint, and a
transverse incision from the inner to the outer side of'
the leg, at the lower end of the vertical incision. The
flaps of integument having been removed, the super-
ficial and deep fascise should be examined. The more
advanced student should commence the study of this
region by an examination of the anatomy of femoral
hernia, and Scarpa's triangle, the incisions for the dis-
section of which are marked out in the accompanying
figure.
Fascije of the Thigh.
■RONTafTHl.'iH
The Superficial fascia forms a continuous
layer over the whole of the lower extremity,
consisting of areolar tissue, containing in its
meshes much adipose matter, and capable
of being separated into two or more layers,
between which are found the superficial
vessels and nerves. It varies in thickness,
in difl'erent parts of the limb ; in the sole of
the foot it is so thin as to be scarcely demon-
strable, the integument being closely ad-
herent to the deep fascia beneath, but in the
groin it is thicker, and the two layers are
separated from one another by the super-
ficial inguinal glands, the internal saphenous
vein, and several smaller vessels. One of
tlicse two layers, the superficial, is continu-
ous above with the superficial fascia of the
// , DonsuM^/* FOOT abdomen, the deep layer becoming blended
with the fascia lata, a little below JPoupart's
ligament. The deep layer of superficial
rr.ONTr(» LEO
FASCIA OF THE THIGH.'
433
fascia is intimately adherent to tlie margins
of the saphenous opening in the fascia lata,
and pierced in this situation by numerous
small blood and lymphatic vessels : hence
the name cribriform fascia^ which has been
applied to it. Subcutaneous burste are found
in the superficial fascia over the patella,
point of the heel, and phalangeal articula-
tions of the toes.
The deep fascia of the thigh is exposed on
the removal of the superficial fascia, and is
named, from its great extent, the fascia lata ;
it forms a uniform investment for the whole
of this region of the limb, but varies in
thickness in different parts ; thus it is thicker
in the upper and outer part of the thigh,
where it receives a fibrous expansion from
the Gluteus maximus muscle, and the Tensor
vaginae femoris is inserted between its layers ;
it is very thin behind, and at the upper and
inner part, where it covers the Adductor
muscles, and again becomes stronger around
the knee, receiving fibrous expansions from
the tendon of the Biceps externally, and
from the Sartorius, Gracilis, Semitendinosus,
and Quadriceps extensor cruris in front. The
fascia lata is attached, above, to Poupart's
ligament, and the crest of the ilium ; behind,
to the margin of the sacrum and coccyx;
internally, to the pubic arch, and linea ilio-
pectinea ; and below to all the prominent
points around the knee-joint, the condyles
of the femur, tuberosities of the tibia, and
head of the fibula. That portion which
invests the Gluteus medius (the Gluteal
aponeurosis) is very thick and strong, and
gives origin, by its inner surface, to some of
the fibres of that muscle; at the upper
border of the Gluteus maximus, it divides
into two layers, the upper of which, very
thin, covers the surface of the Gluteus maxi-
mus, and is continuous below with the fascia
lata : the deep layer is thick above, where
it blends with the great sacro- sciatic liga-
ment, thin below, where it separates the
Gluteus maximus from the deeper muscles.
From the inner surface of the fascia lata are
given off two strong intermuscular septa,
which are attached to the whole length of
the linea aspera : the external and stronger
one, which extends from the insertion of the
Gluteus maximus to the outer condyle, sepa-
rates the Vastus externus in front from the
short head of the Biceps behind, and gives
partial origin to those muscles ; the inner
one, the thinner of the two, separates the
Vastus internus from the Adductor muscles.
28
Fig. 284. — Muscles of the Iliac aiu
Aiiterioi" Femoral Reorious.
434 ■ MUSCLES AND FASCIA.
Besides these, tliere are numerous smaller septa, separating tlie individual
muscles, and inclosing each in a distinct sheath. At the upper and inner part
of the thigh, a little below Poupart's ligament, a large oval-shaped aperture is
observed after the superficial fascia has been cleared oft': it transmits the internal
saphenous vein, and other smaller vessels, and is termed the saphenous opening.
In order more correctly to consider the mode of formation of this aperture, the
fascia lata is described as consisting, in this part of the thigh, of two portions,
an iliac portion, and a pubic portion.
The iliac portion is all that part of the fascia lata on the outer side of the
saphenous opening. It is attached, externally, to the crest of the ilium, and its
anterior superior spine, to the whole length of Poupart's ligament, as far inter-
nally as the spine of the pubes, and to the pectineal line in conjunction with
Gimbernat's ligament. From the spine of the pubes, it is reflected downwards
and outwards, forming an arched margin, the sujDerior cornu, or outer boundary
of the saphenous opening ; this margin overlies, and is adherent to the anterior
layer of the sheath of the femoral vessels : to its edge is attached the cribriform
fascia, and, below, it is continuous with the pubic portion of the fascia lata.
T-he p)iLhic portion is situated at the inner side of the saphenous opening ; at
the lower margin of this aperture it is continuous with the iliac portion ; traced
upwards, it is seen to cover the surface of the Pectineus muscle, and passing
behind the sheath of the femoral vessels, to which it is closely united, is con-
tinuous with the sheath of the Psoas and Iliacus muscles, and is finally lost in
the fibrous capsule of the hip-joint. This fascia is attached above to the pectineal
line in front of the insertion of the aponeurosis of the external oblique, and
internally to the margin of the pubic arch. From this description it may be
observed that the iliac portion of the fascia lata passes in front of the femoral
vessels, and the pubic portionbehind them, so that an apparent aperture exists"
between the two, through which the internal saphenous joins the femoral vein.'
The fascia should now be removed from tlie surface of the mnscles. This may be effected by
pinchiiiff it up between the forceps, dividing it, and separating it from each muscle in the course
of its fibres.
The Tensor Vaginse Femoris is a short flat muscle, situated at the uj^per and
outer side of the thigh. It arises from the anterior part of the outer lip of the
crest of the ilium, and from the outer surface of the anterior superior spinous
process, between the Gluteus mediiis and Sartorius. The muscle passes obliquely
downwards, and a little backwards, to be inserted into the fascia lata, about
one-fourth down the outer side of the thigh.
Relations. By its superficial surface, with the fascia lata and the integument.
By its deep surface, with the Gluteus medius, Pectus femoris, Yastus externus,
and the ascending branches of the external circumflex artery. By its anterior
border, with the Sartorius, from which it is se]3arated below by a triangular
space, in which is seen the Pectus femoris. By its posterior border, with the
Gluteus rncdius.
The Sartorius, the longest muscle in the body, is flat, narrow, and riband-like:
it arises by tendinous fibres from the anterior superior spinous process of the
ilium and the upper half of the notch below it, passes obliquely across the upper
and anterior part of the thigh, from the outer to the inner side of the limb, then
descends vertically, as far as llie inner side of the knee, passing behind the inner
condyle of the femur, and terminates in a tendon, which, curving obliquely for-
wards, expands into a broad aponeurosis, inserted into the upper part of the
inner .siirracc of the shaft of the tibia, nearly as far forwards as the crest. This
expansion covers the insertion of the tendons of the Gracilis and Semitendi-
noHus, with which it is partially unitofl, a synovial bursa being interposed be-
tween them. An oH'sct is dcrive.fl (Vom ihc ii]i]i(>r margin of this aponeurosis,
wliif.li blends with the fibrous capsule oC the kucc-joint, and another, given olf
' Tho=c parts will be npain more particularly described with the anatomy cjf ITernia.
ANTERIOR FEMORAL REGION. 435
from its lower border, blends with, tlie fascia on the inner side of tlie leg. The
relations of this muscle to the femoral artery should be carefully examined, as
its inner border forms the chief guide in tying the artery. In the upper third
of the thigh, it forms the outer side of a triangular space, Scarpa's triangle, the
inner side of which is formed by the Adductor longus, and the base, turned
upwards, by Poupart's ligament; the femoral artery passes perpendicularly
through the middle of this space from its base to its apex. In the middle third
of the thigh, the femoral artery lies first along the inner border, and then behind
the Sartorius.
Relations. By its superficial surface^ with the fascia lata and integument. By
its deep surface^ with the Iliacus, Psoas, Pectus, Vastus internus, anterior crural
nerve, sheath of the femoral vessels. Adductor longus. Adductor maguus, Gracilis,
long saphenous nerve, and internal lateral ligament of the knee-joint.
The Quadriceps extensor includes the four remaining muscles on the front of
the thigh. It is the great Extensor muscle of the leg, forming a large fleshy
mass, which covers the front and sides of the femur, being united below into a
single tendon, attached to the tibia, and above subdividing into separate portions
which have received distinct names. Of these, one occupying the middle of the
thigh, connected above with the ilium, is called the Rectus femoris^ from its
straio;ht course. The other divisions lie in immediate connection with the shaft
of the femur, which they cover from the condyles to the trochanters. The portion
on the outer side of the femur is termed the Vastus externus ; that covering the
inner side, the Vastus internus ; and that covering the front of the femur, the
Crureus. The two latter portions are, however, so intimately blended, as to
form but one muscle.
The Rectus Fem.oris is situated in the middle of the anterior region of the
thigh ; it is fusiform in shape, and its fibres are arranged in a bipenniform manner.
It arises by two tendons : one, the straight tendon, or short head, from the anterior
inferior spinous process of the ilium ; the other is flattened, and curves outwards,
to be attached to a groove above the brim of the acetabulum ; this is the reflected
tendon, or long head, of the Pectus ; it unites with the straight tendon at an
acute angle, and then spreads into an aponeurosis, from which the muscular
fibres arise. The muscle terminates in a broad and thick aponeurosis, whicli
occupies the lower two-thirds of its posterior surface, and, gradually becoming
narrowed into a flattened tendon, is inserted into the patella in common with
the Yasti and Crureus.
Relations. By its superficial surface.^ with the anterior fibres of the Gluteus
minimus, the Tensor vaginae femoris, Sartorius, and the Psoas and Iliacus ; by its
lower three-fourths, with the fascia lata. By its posterior surface with the hip-
joint, the external circumflex vessels, and the Crureus and Vasti muscles.
The three remaining muscles have been described collectively by some anato-
mists, separate from the Pectus, under the name of the Triceps extensor cruris.
In order to expose them, divide the Sartorius and Rectus across the middle, and
turn them aside, when the muscles in question will be fully brought into view.
The Vastus Externus is the largest part of the Quadriceps extensor. It arises
by a broad aponeurosis, which is attached to the tubercle of the femur, to the
anterior border of the great trochanter, to a horizontal ridge on its outer surface,
to a rough line leading from the trochanter major to the linea aspera, and to the
whole length of the outer lip of the linea aspera; this aponeurosis covers the
upper three-fourths of the muscle, and from its inner surface many fibres arise.
A few additional fibres arise from the tendon of the Gluteus maximus, and from
the external intermuscular septum between the Vastus externus, and short head
of the Biceps. The fibres form a large fleshy mass, which is attached to a strong
aponeurosis, placed on the under surface of the muscle at its lower part : this be-
comes contracted and thickened into a flat tendon, which is inserted into the
outer border of the patella, blending with the great extensor tendon.
Relations. By its superficial surface^ with the Pectus, the Tensor vaginas
436 MUSCLES AND FASCIA.
femoris, the fascia lata, and the Gluteus maximus, from which it is separated by
a synovial bursa. By its deej) surface^ with the Crureus, some large branches of
the external circumflex artery and anterior crural nerve being interposed.
The Vastus Internus and Crureus are so inseparably connected together, as to
form but one muscle, as which it will be accordingly described. It is the smallest
portion of the Quadriceps extensor. The anterior portion of it, covered by the
Eectus, is called the Crureus; the internal portion, which lies immediately
beneath the fascia lata, the Vastus internus. It arises by an aponeurosis, which
is attached to the lower part of the line that extends from the inner side of the
neck of the femur to the linea aspera, from the whole length of the inner lip of
the linea aspera, and internal intermuscular septum. It also arises from nearly
the whole of the internal, anterior, and external surfaces of the shaft of the femur,
limited, above, by the line between the two trochanters, and extending, below,
to within the lower fourth of the bone. From these different origins, the fibres
converge to a broad aponeurosis, which covers the anterior surface of the middle
portion of the muscle (the Crureus), and the deep surface of the inner division
of the muscle (the Vastus internus), and which gradually narrows down to its
insertion into the patella, where it blends with the other portions of the Quadri-
ceps extensor. The muscular fibres of the Vastus internus extend lower down-
than those of the Vastus externus, so that the capsule of the joint is less covered
with muscular fibres on the outer than on the inner side.
Relations. By its superficial surface^ with the Psoas and Iliacus, the Eectus,
Sartorius, Pectineus, Adductors, and fascia lata, femoral vessels, and saphenous
nerve. By its deep surface, with the femur, Subcrureus, and synovial membrane
of the knee-joint.
The student will observe the striking analogy that exists between the Quadri-
ceps extensor and the Triceps muscle in the upper extremity. So close is this
similarity, that M. Cruveilhier has described it under the name of the Tricep)s
feraoralis. Like the Triceps brachialis, it consists of three distinct divisions, or
heads : a middle or long head, analogous to the long head of the Triceps, attached
to the ilium, and two other portions which may be called the external and
internal heads of the Triceps femoralis. These, it will be noticed, are strictly
analogous to the outer and inner heads of the Triceps brachialis.
The tendons of the different portions of the Quadriceps extensor unite at the
lower part of the thigh, so as to form a single strong tendon, which is inserted
into the upper part of the patella. More properly, the patella may be regarded
as a sesamoid bone, developed in the tendon of the Quadriceps ; and the liga-
mentum patellas, which is continued from the lower part of the patella to the
tuberosity of the tibia, as the proper tendon of insertion of the muscle. A syno-
vial bursa is interposed between the tendon and the upper part of the tuberosity
of the tibia. From the tendons corresponding to the Vasti, a fibrous prolonga-
tion is derived, which is attached below to the upper extremities of the tibia and
fibula, and which serves to protect the knee-joint, being strengthened on its
outer side by the fascia lata.
The Suhcrurev.s is a small muscle, usually distinct from the Crureus, but occa-
sionally blended with it, which arises from the anterior surface of the lower part
of the shaft of the femur, and is inserted into the upper part of the synovial
j)Ouch that extends upwards from the knee-joint behind the pateha. It some-
times consists of two separate muscular bundles.
Nerves. The Tensor vaginae femoris is supplied by the superior gluteal nerve ;
the otIifT muscles of this region, by branches from the antcriiu' crural.
Arf.ions. Tlio Tensor vaginin femoris is a tensor of the fascia lala; continuing
itsaction, thcol)lif|nc direction of its fibres enables it to rotate the thigh inwards.
In the erect posture, acting from below, it will serve to steady the pelvis upon
the head of the femur. The Sartorius flexes the leg upon the thigh, and con-
tinuing to act, flexes the thigh upon the pelvis, at the same time drawing the
limb inwards, so as 1o cross one leg over Ihc other. Taking its fixed point from
INTERNAL FEMORAL REGION.
437
Fig. 285. — Deep Muscles of the Internal
Femoral Eecfion.
the leg, it flexes the pelvis upon tlie tliigh, and, if one muscle acts, assists in
rotating the pelvis. The Quadriceps extensor extends the leg upon the thigh.
Taking its fixed point from the leg, as in standing, this muscle will act upon
the femur, supporting it perpendicularly
upon the head of the tibia, and thus main-
taining the entire weight of the body.
The Eectus muscle assists the Psoas and
Iliacus, in supporting the pelvis and trunk
upon the femur, or in bending it for-
wards.
Interi^al Femoral Eegion.
Gracilis.
Pectineus.
Adductor Longus.
Adductor Brevis.
Adductor Magnus.
Dissection. These muscles are at once exposed
by removing the fascia from the fore part aud inner
side of the thigh. The limb should be abducted, so
as to render the muscles tense, and easier of dis-
section.
The Gracilis (Figs. 284, 287) is the most
superficial muscle on the inner side of the
thigh. It is thin and flattened, broad
above, narrow and tapering below. It
arises by a thin aponeurosis between two
and three inches in breadth, from the inner
margin of the ramus of the pubes and
ischium. The fibres pass vertically down-
wards, and terminate in a rounded tendon
which passes behind the internal condyle
of the femur, and curving round the inner
tuberosity of the tibia, becomes flattened,
and is inserted into the upper part of the
inner surface of the shaft of the tibia,
below the tuberosity. The tendon of this
muscle is situated immediately above that
of the Semitendinosus, and beneath the
aponeurosis of the Sartorius, with which
it is in part blended. As it passes across
the internal lateral ligament of the knee-
joint, it is separated from it by a synovial
bnrsa common to it and the Semitendi-
nosus muscle.
Relations. By its superficial surface^
with the fascia lata and the Sartorius
below ; the internal saphenous vein crosses
it obliquely near its lower part, lying
superficial to the fascia lata. The anterior
crural nerve emerges between its tendon
and that of the Sartorius. By its deep
surface, with the three Adductors, and the
internal lateral ligament of the knee-joint.
The Pectineus (Fig. 284) is a flat quad-
rangular muscle, situated at the anterior
438 MUSCLES AND FASCIA.
part of the upper and inner aspect of the tliigh. It arises from tlie linea ilio-
pectinea, from the surface of bone in front of it, between the pectineal eminence
and spine of the pubes, and from a tendinous prolongation of Gimbernat's liga-
ment, which is attached to the crest of the pubes, and is continuous with the
fascia covering the anterior surface of the muscle ; the fibres pass downwards,
backwards, and outwards, to be inserted into a rough line leading from the tro-
chanter minor to the linea aspera.
Relations. By its anterior surface^ with the pubic portion of the fascia lata,
which separates it from the femoral vessels and internal saphenous vein. By
its posterior surface^ with the hip-joint, the Adductor brevis and Obturator
externus muscles, the obturator vessels and nerve being interposed. By its
outer border^ with the Psoas, a cellular interval separating them, upon which lies
the femoral artery. By its inner harder^ with the margin of the Adductor
longus.
The Adductor Longus, the most superficial of' the three Adductors, is a flat
triangular muscle, lying on the same plane as the Pectineus, with which it is
often blended above. It arises, by a flat narrow tendon, from the front of the
pubes, at the angle of junction of the crest with the symphysis; and soon
expands into a broad fleshy belly, which, passing downwards, backwards, and
outwards, is inserted, by an aponeurosis, into the middle third of the linea aspera,
between the Vastus internus and the Adductor magnus.
Relations. By its anterior surface, with the fascia lata, and, near its insertion,
with the femoral artery and vein. By its posterior surface, with the Adductor
brevis and magnus, the anterior branches of the obturator vessels and nerve,
and with the profunda artery and vein near its insertion. By its outer border,
with the Pectineus. By its inner border, with the Gracilis.
The Poctiiiens and Adductor longiis should now be divided near their origin, and turned doAvn-
wards, when the Adductor brevis and Obturator externus will be exposed.
The Adductor Brevis is situated immediately behind the two preceding mus-
cles. It is somewhat triangular in form, and arises by a narrow origin from the
outer surface of the descending ramus of the pubes, between the Gracilis and
Obturator externus. Its fibres, passing backwards, outwards, and downwards,
are inserted, by an aponeurosis, into the upper part of the linea aspera, imme-
diately behind the Pectineus and upper part of the Adductor longus.
Relations. By its anterior surface, with the Pectineus, Adductor longus, and
anterior branches of the obturator vessels and nerve. By its posterior surface,
with the Adductor magnus, and posterior branches of the obturator vessels and
nerve. By its outer border, with the Obturator externus, and conjoined tendon
of the Psoas and Iliacus. By its inner border, witli the Gracilis and Adductor
magnus. This muscle is pierced, near its insertion, by the middle perforating
branch of the profunda artery.
'I"hn Adductor brevis should now be out away near its origin, and turned outwards, when the
entire extent of the Adductor magnus will be exposed.
The Adductor Mafpius is a large triangular muscle, forming a septum between
tlie muscles on the inner and those on the back of the thigh. It arises from
a small part of tlio descending ramus of tlie pubes, from the ascending ramus of
the ischium, and from the outer margin find under surface of tlic tuberosity of
the ischium. IMiosc fibres which arise from the ramus of the pubes are very
short, horizontal in direction, and are inserted into the rough line leading from
the great trochanter to the linea aspera, internal to the Gluteus maximus; those
from the ramus of the ischium are directed downwards and outwards with
difTercnt degrees of obliquity, to be inserted, by means of a broad aponeurosis,
into tlie wliole length of the linea aspera and the upper jiart of its interuHl
T)i furcation below. The internal portion of the muscle, consisting principally
of those fibres which arise from the tuberosity of the ischium, forms a thick
flcsliy mass consisting of coarse bundles which descend almost vertically, and
GLUTEAL REGION. 439
terminate about the lower tliird of tlie tliigh in a rounded tendon, wliicli is
inserted into the tubercle above the inner condyle of the femur, being connected
bj a fibrous expansion to the line leading upwards from the tubercle to the
linea aspera. Between the two portions of the muscle an angular interval is
left, tendinous in front, fleshy behind, for the passage of the femoral vessels into
the popliteal space. The external portion of the muscle is pierced by four
apertures; the three superior, for the three superior perforating arteries ; the
fourth, for the passage of the profunda. This muscle gives off' an aponeurosis,
which passes in front of the femoral vessels, and joins with the Vastus internus.
Relations. By its oMerior surface^ with the Pectineus, Adductor brevis. Ad-
ductor longus, and the femoral vessels. By its posterior surface^ with the great
sciatic nerve, the Grluteus maximus, Biceps, Semitendinosas, and Semimembra-
nosus. By its superior or shortest border, it lies parallel with the Quadratus
femoris, the internal circumflex artery passing between them. By its internal
or longest border, with the Gracilis, Sartorius, and fascia lata. By its external or
attached border, it is inserted into the femur behind the Adductor brevis and
Adductor longus, which separate it from the Vastus internus ; and in front of
the Gluteus maximus and short he^d of the Biceps, which separate it from the
Vastus externus.
Nerves. All the muscles of this group are supplied by the obturator nerve.
The Pectineus receives additional branches from the accessory obturator and
anterior crural ; and the Adductor magnus an additional branch from the great
sciatic.
Actions. The Pectineus and three Adductors adduct the thigh powerfully ;
they are especially used in horse exercise, the flanks of the horse being grasped
between the knees by the action of these muscles. In consequence of the
obliquity of their insertion into the linea aspera, they rotate the thigh outwards,
assisting the external Eotators, and when the limb has been abducted, they draw
it inwards, carrying the thigh across that of the opposite side. The Pectineus
and Adductor brevis and longus assist the Psoas and Iliacus in flexing the thigh
upon the pelvis. In progression, also, all these muscles assist in drawing for-
wards the hinder limb. The Gracilis assists the Sartorius in flexing the leg and
drawing it inwards ; it is also an Adductor of the thigh. If the lower extremi-
ties are fixed, these muscles may take their fixed point from below and act upon
the pelvis, serving to maintain the body in the erect posture ; or, if their action
is continued, to flex the pelvis forwards upon the femur.
Gluteal Region.
Gluteus Maximus. Gemellus Superior.
Gluteus Medius. Obturator Internus.
Gluteus Minimus. Gemellus Inferior.
Pyriformis. Obturator Externus.
Quadratus Femoris.
Dissection (Fig. 286). The subject should be turned on its face, a block placed beneath the
pelvis to make the buttocks tense, and the limbs allowed to hang over the end of the talile. wiih
the foot inverted, and the thigh abducted. Make an incision through th-e integument along the
back part of the crest of the ilium and margin of the sacrum to the tip of the coccyx, and carry a
second incision from that point obliquely downwards and outwards to the outer side of the thigh,
four inches below the great trochanter. The portion of integument included between these
incisions, together with the superficial fascia, is to be removed in the direction shown in the
figure, when the Gluteus maximus and the dense fascia covering the Gluteus medius will be exposed.
The Gluteus Maximus (Fig. 287), the most superficial muscle in the gluteal
region, is a very broad and thick fleshy mass, of a quadrilateral shape, which
forms the prominence of the nates. Its large size is one of the most characteristic
points in the muscular system in man, connected as it is with the power he has
of maintaining the trunk in the erect posture. In structure the muscle is
440
MUSCLES AND FASCIA.
Fig. 286.— Dissection of Lower Ex-
tremity. Posterior View.
/ , Dissection of
GLUTEAL RECiON
te-N
BACK of THIGH
POPLITEAL SPACE
BACK nf LEG
remarkably coarse, being made up of muscular fasciculi lying parallel witli one
anotlier, and collected together into large bundles, separated by deep cellular
intervals. It arises from the superior curved
line of the ilium, and the portion of bone in-
cluding the crest, immediately behind it ; from
the posterior surface of the last piece of the
sacrum, the side of the coccyx, and posterior
surface of the great sacro-sciatic and posterior
sacro-iliac ligaments. The fibres are directed
obliquely downwards and outwards ; those
forming the upper and larger portion of the
muscle (after converging somewhat) terminate
in a thick tendinous lamina, which passes across
the great trochanter, and is inserted into the
fascia lata covering the outer side of the thigh,
the lower portion of the muscle being inserted
into the rough line leading from the great tro-
chanter to the linea aspera between the Yastus
externus and Adductor magnus.
Three synovial bursas are usually found sepa-
rating the under surface of this muscle from
the eminences which it covers. One of these,
of large size, and generally multilocular, sepa-
rates it from the great trochanter. A second,
often wanting, is situated on the tuberosity of
the ischium. A third is found between the"
tendon of this muscle and the Vastus externus.
delations. By its superficial surface^ with a
thin fascia, which separates it from the sub-
cutaneous tissue. By its cZeejj surface^ from
above downwards, with the ilium, sacrum,
coccyx, and great sacro-sciatic ligament, part
of the Gluteus medius, Pyriformis, Gemelli,
Obturator internus, Quadratus femoris, the
tuberosity of the ischium, great trochanter,
the origin of the Biceps, Semitendinosus, Semi-
membranosus, and Adductor magnus muscles.
The gluteal vessels and superior gluteal nerve
Jive seen issuing from the pelvis above the Pyriformis muscle, the sciatic and
internal pubic vessels and nerves, and the nerve to the Obturator internus muscle
below it. Its wpper harder is thin, and connected with the Gluteus medius by
the fascia lata. Its lower harder^ free and prominent, forms the fold of the nates,
and is directed towards the perineum.
Dissection. Now divide the Gluteus maximns near its origin, by ^ vortical incision carried
from its upper to its lower border; a cellular interval will be exiiosed. separating it from the
(JIuleus medius and External rotator muscles beneath. Tiie upper portion oi' the muscle is to be
jiltogetlier detached, and the lower portion turned outwards ; the loose areolar tissue filling up
ihe interspace between the trochanter major and tul)erosity of the ischium being removed, the
parts already enumerated as ex[)osed by the removal of this muscle will be seen.
Tlio Ghdev,s Medius is ;i broad, tlii(;Ic, radi;U('(l muscle, situated on tlic outer
surface of tlic pelvis. Its ])OKtcrior third is covered by the Gluteus maximus; its
anterior two-thirds by the fascia lata, which separates it from the integument.
It arises from the outer surface of the ilium, between the superior and middle
curved lines, and from the outer lip of that portion of the crest which is between
them; it also arises ffim the dense fascia (gluteal aponeurosis) covering its
anterior part. Tlio fibres converge to a strong flattonod tendon, Avhich is inserted
into the oblique line which tJ'a verses the outer surface of the great trochanter.
w\
f FC
GLUTEAL REGION.
441
A synovial bursa separates the
tendon of the muscle from the
surface of the trochanter in
front of its insertion.
Relations. By its superficial
surface, with the Gluteus maxi-
mus behind, the Tensor vaginaa
femoris, and deep fascia in front.
By its deep surface, with the
Gluteus minimus and the glu-
teal vessels and superior gluteal
nerve. Its anterior horder is
blended with the Gluteus mini-
mus. Its posterior horder lies
parallel with the Pyriformis,
the gluteal vessels intervening.
This muscle sliould now be divided
near its insertion and turned upwards,
when the Gluteus minimus will be
exposed.
The Gluteus Minimus, the
smallest of the three glutei, is
placed immediately beneath the
preceding. It is fan-shaped,
arisino; from the outer surface
of the ilium, between the mid-
dle and inferior curved lines,
and behind, from the margin
of the great sacro-sciatic notch :
the fibres converge to the deep
surface of a radiated aponeu-
rosis, which, terminating in a
tendon, is inserted into an im-
pression on the anterior border
of the great trochanter. A
synovial bursa is interposed
between the tendon and the
great trochanter.
delations. By its superficial
surface, with the Gluteus
medius, and the gluteal vessels
and superior gluteal nerve.
By its deep surface, with the
ilium, the reflected tendon of
the Kectus femoris, and capsu-
lar ligament of the hip-joint.
Its anterior margin is blended
with the Gluteus medius. Its
posterior margin is often joined
with the tendon of the Pyri-
formis.
The Pyriform^is is a flat mus-
cle, pyramidal in shape, lying
almost parallel with the poste-
rior margin of the Gluteus
medius. It is situated partly
within the pelvis at its poste-
Fig. 287.— Muscles of the Hip and Thigh.
442 MUSCLES AND FASCIA.
rior part, and partly at the back of tlie liip-joint. It arises from tlie front of
tlie sacrum bj tbree fleshy digitations, attached to the portions of bone between
the first, second, third, and fourth anterior sacral foramina, and also from the
grooves leading from the foramina: a few fibres also arise from the margin of
the great sacro-sciatic foramen, and from the anterior surface of the great sacro-
sciatic ligament. The muscle passes out of the pelvis through the great sacro-
sciatic foramen, the upper part of which it fills, and is inserted by a rounded
tendon into the upper border of the great trochanter, being generally blended
with the tendon of the Obturator internus.
Relations. By its anterior surface^ toithin the pelvis^ with the Eectum (especially
on the left side), the sacral jdIcxus of nerves, and the internal iliac vessels ; ex-
ternal to the pelvis^ with the os innominatum and capsular ligament of the hip-
joint. By ii^ posterior surface^ within the pelvis^ with the sacrum; and external
to it^ with the Gluteus maximus. By its upp)er border^ with the Gluteus inedius,
from which it is separated by the gluteal vessels and superior gluteal nerve.
By its loiver horder^ with the Gemellus superior and Coccygeus; the sciatic
vessels and nerves, the internal pudic vessels and nerve, and the nerve to the
Obturator internus, passing from the pelvis in the interval between the two
muscles.
Dissection. The next muscle, as well as the origin of the Pyriformis, can only be seen when
the pelvis is divided, and the viscera removed.
The Obturator membrane is a dense layer of interlacing fibres, which completely
closes the obturator foramen, except at its upper and outer part, where a small
oval canal is left for the obturator vessels and nerve. Each obturator muscle
is connected with this membrane.
The Obturator Internus^ like the preceding muscle, is situated partly within
the cavity of the pelvis, partly at the back of the hip-joint. It arises from the
inner surface of the anterior and external wall of the pelvis, around the inner
side of the obturator foramen, being attached to the descending ramus of the
pubes, and the ascending ramus of the ischium, and at the side to the inner
surface of the body of the ischium, between the margin of the obturator foramen
in front, the great sacro-sciatic notch behind, and the brim of the true pelvis
above. It also arises from the inner surface of the obturator membrane and
from the tendinous arch which completes the canal for the passage of the
obturator vessels and nerve. The fibres are directed backwards and downwards,
and terminate in four or five tendinous bands, which are found on its deej:)
surface ; these bands are reflected at a right angle over the inner surface of the
tuberosity of the ischium, which is grooved for their reception : the groove is
covered with cartilage, and lined with a synovial bursa. The muscle leaves the
pelvis by the lesser sacro-sciatic notch; and the tendinous bands unite into a
single flattened tendon, which passes horizontally outwards, and, after receiving
the attachment of the Gemelli, is inserted into the upper border of the great
trochanter in front of the Pyriformis. A synovial bursa, narrow and elongated
in form, is usually found between the tendon of this mtiscle and the capsular
ligament of the hip: it occasionally communicates with that between the tendon
and the tuberosity of the ischium, the two forming a single sac.
In order to display the pocnliar appearances presented by the tendon of this nniscle, it must be
divided near its insertion and reflected outwards.
Relations. Witliin the pelvis^ lliis muscle is in rchition, b\^ its anterior surface,
with the obturator membrane and inner surface of the anterior wall of the
pelvis; by its posterior surface, with the pelvic and obturator fasciiX3, which
separate it from the Levator ani; and it is crossed by the internal pudic vessels
and nerve. This surface forms the outer boundary of the ischio-rcctal fossa.
External to the pelvis, it is covered by the great sciatic nerve and Gluteus
maximus, and rests on the back ])art of tlie hip-joint.
The GernelU are two small muscular fasciculi, accessories to the tendon of the
GLUTEAL REGION. 443
Obturator internus, wliicli is received into a groove between them. They are
called superior and inferior.
The Gemellus Sicjoerior, the smaller of the two, arises from the outer surface
of the spine of the ischium, and passing horizontally outwards becomes blended
with the upper part of the tendon of the Obturator internus, and is inserted
with it into the uj)per border of the great trochanter. This muscle is sometimes
wanting.
delations. By its superficial surface^ with the Gluteus maximus and the sciatic
vessels and nerves. By its deep surface^ with the capsule of the hip-joint. By
its upper harder^ with the lower margin of the Pyriformis. By its loioer border^
with the tendon of the Obturator internus.
The Gemellus Inferior arises from the upper part of the outer border of the
tuberosity of the ischium, and passing horizontally outwards is blended with the
lower part of the tendon of the Obturator internus, and inserted with it into the
upper border of the great trochanter.
delations. By its superficial surface^ with the Gluteus maximus and the sciatic
vessels and nerves. By its deep surface^ with the capsular ligament of the hip-
joint. By its upper border, with the tendon of the Obturator internus. By
its lower border^ with the tendon of the Obturator externus and Quadratus
femoris.
The Quadratus Femoris is a short, flat muscle, quadrilateral in shape (hence
its name), situated between the Gemellus inferior and the upper margin of the
Adductor magnus. It arises from the outer border of the tuberosity of the
ischium, and proceeding horizontally outwards is inserted into the upper part
of the linea quadrati, on the posterior surface of the trochanter major. A syno-
vial bursa is often found between the under surface of this muscle and the lesser
trochanter, which it covers.
Relations. By its posterior surface, with the Gluteus maximus and the sciatic
vessels and nerves. By its anterior surface, with the tendon of the Obturator ex-
ternus and trochanter minor, and with the capsule of the hip-joint. By its upper
border, with the Gemellus inferior. Its loiver border is separated from the Ad-
ductor magnus by the terminal branches of the internal circumflex vessels.
DissecMon. In order to expose the next muscle (the Obturator externus), it is necessary to
remove the Psoas, Iliacus, Pectineus, and Adductor brevis and longus muscles from the front and
inner side of the thigh ; and the Gluteus maximus and Quadratus femoris from the back part.
Its dissection should, consequently, be postponed until the muscles of the anterior and internal
femoral regions have been examined.
The Obturator Externus (Fig. 285) is a flat triangular muscle, which covers
the outer surface of the anterior wall of the pelvis. It arises from the margin
of bone immediately around the inner side of the obturator foramen, viz. from
the body and ramus of the pubes, and the ramus of the ischium; it also arises
from the inner two-thirds of the outer surface of the obturator membrane, and
from the tendinous arch which completes the canal for the passage of the obtu-
rator vessels and nerves. The fibres converging pass outwards and backwards,
and terminate in a tendon which runs across the back part of the hip-joint, and
is inserted into the digital fossa of the femur.
Relations. By its anterior surface, with the Psoas, Iliacus, Pectineus, Adductor
longus, Adductor brevis, and Gracilis ; and more externally, with the neck of
the femur and capsule of the hip-joint. By its posterior surface, with the obtu-
rator membrane and Quadratus femoris.
Nerves. The Gluteus maximus is supplied by the inferior gluteal nerve and
a branch from the sacral plexus; the Gluteus medius and minimus, by the supe-
rior gluteal ; the Pyriformis, Gemelli, Obturator internus, and Quadratus femoris,
by branches from the sacral plexus, and the Obturator externus, by the obturator
nerve.
Actions. The Glutei muscles, when they take their fixed point from the pelvis,
are all abductors of the thigh. The Gluteus maximus and the posterior fibres
444 MUSCLES AND FASCIAE.
of tile Gluteus medius, rotate tlie tliigli outwards ; the anterior fibres of tlie Glu-
teus medius and tlie Gluteus minimus rotate it inwards. The Gluteus maximus
serves to extend the femur, and the Gluteus medius and minimus draw it for-
wards. The Gluteus maximus is also a tensor of the fascia lata. Taking their
fixed point from the femur the Glutei muscles act upon the pelvis, supporting it
and the whole trunk upon the head of the femur, which is specially obvious in
standing on one leg. In order to gain the erect posture after the eftbrt of stoop-
ing, these muscles draw the pelvis backwards, assisted by the Biceps, Semiten-
dinosus, and Semimembranosus muscles. The remaining muscles are powerful
rotators of the thigh outwards. In the sitting posture, when the thigh is flexed
upon the pelvis, their action as rotators ceases, and they become abductors, with
the exception of the Obturator externus, which still rotates the femur outwards.
When the femur is fixed, the Pyriformis and Obturator muscles serve to draw
the pelvis forwards if it has been inclined backwards, and assist in steadying it
upon the head of the femur.
PosTEEiOE Femoral Eegion.
Biceps. Semitendinosus. Semimembranosus.
Dis!^ection (Fig. 286). Make a vertical incision along the middle of the thigh, from the lower
fold of the nates to about three inches below the back of the knee-joint, and there connect it with
a transverse incision, carried from the inner to the outer side of the leg. Make a third incision
transversely at the junction of the middle with the lower third of the thigh, "^rhe integument
having been removed from the back of the knee, and the boundaries of the popliteal space exam-
ined, the removal of the integument from the remaining part of the thigh should be continued,
when the fascia and muscles of this region will be exposed.
The Biceps (Fig. 287) is a large muscle, of considerable length, situated on the '
posterior and outer aspect of the thigh. It arises by two heads. One, the long-
head, arises from the lower and inner facet on the back part of the tuberosity
of the ischium, by a tendon common to it and the Semitendinosus. The femoral,
or short head, arises from the outer lip of the linea aspera, between the Adductor
magnus and Yastus externus, extending from a short distance below the inser-
tion of the Gluteus maximus, to within two inches of the outer condyle ; it also
arises from the external intermuscular septum. The fibres of the long head
form a fusiform belly, which, passing obliquely downwards and a little outwards,
terminate in an aponeurosis which covers the posterior surface of the muscle,
and receives the fibres of the short head ; this aponeurosis becomes gradually
contracted into a tendon, which is inserted into the outer side of the head of the
fibula. At its insertion, the tendon divides into two portions, which embrace
the external lateral ligament of the knee-joint, a strong prolongation being sent
forwards to the outer tuberosity of the tibia, which gives off an expansion to the
fascia of the leg. The tendon of this muscle forms the outer ham-string.
Relations. By its superficial surface^ with the Gluteus maximus above, the
fascia lata and integument in the rest of its extent. By its deep surface^ with the
Semimembranosus, Adductor magnus, and Vastus externus, the great sciatic
nerve, popliteal artery and vein, and near its insertion, with the external head
of the Gastrocnemius, Plantaris, the superior external articular arter^^, and the
external popliteal nerve.
11 le Semitendinosus^ remarkable for the great length of its tendon, is situated
at the posterior and inner aspect of the thigh. It arises from the tuberosity of
the iscliium by a tendon common to it and the long head of the Biceps ; it also
arises from an aponeurosis which connects the adjacent surfaces of the two
muscles to the extent of al)out three inches aiter their origin. It forms a fusiform
muscle, which, passing downwards and inwards, terminates a little below the
middle of the thigh in a long round tendon which lies along the inner side of
the popliteal space, then curves around \\\r. inner tuberosity of the tibia, and is
inserted into the upper part of the inner snrl'ace of the shaft of that bone, nearly
as far forwards as its anterior border. This tendon lies beneath the expansion
OF THE LEG. 445
of tlie Sartorius, and below that of tlie Gracilis, to wliich. it is united. A ten-
dinous intersection is usually observed about the middle of the muscle.
Relations. By its superficial surface^ with the Gluteus maximus and fascia
lata. By its deep surface^ with the Semimembranosus, Adductor magnus, inner
head of the Gastrocnemius, and internal lateral ligament of the knee-joint.
The Sem,imev%hranosus^ so called from the membranous expansion on its anterior
and posterior surfaces, is situated at the back part and inner side of the thigh.
It arises by a thick tendon from the upper and outer facet on the back part of
the tuberosity of the ischium, above and to the outer side of the Biceps and
Semitendinosus, and is inserted into the inner and back part of the inner
tuberosity of the tibia, beneath the internal lateral ligament. The tendon of
the muscle at its origin expands into an aponeurosis, which covers the upper
part of its anterior surface : from this aponeurosis, muscular fibres arise, and
converge to another aponeurosis, which covers the lower part of its posterior
surface and contracts into the tendon of insertion. The tendon of the muscle
at its insertion divides into three portions: the middle portion is the fasciculus
of insertion into the back part of the inner tuberosity; it sends down an expan-
sion to cover the Popliteus muscle. The internal portion is horizontal, passing
forwards beneath the internal lateral ligament, to be inserted into a groove along
the inner side of the internal tuberosity. The posterior division passes upwards
and backwards, to be inserted into the back part of the outer condyle of the
femur, forming the chief part of the posterior ligament of the knee-joint.
The tendons of the two preceding muscles, with those of the Gracilis and
Sartorius, form the inner ham-string.
Relations. By its superficial surface^ with the Semitendinosus, Biceps, and
fascia lata. By its deep surface^ with the popliteal vessels. Adductor magnus,
and inner head of the Gastrocnemius, from which it is separated by a synovial
bursa. By its inner border, with the Gracilis. By its outer border, with the great
sciatic nerve, and its internal popliteal branch.
Nerves. The muscles of this region are supplied by the great sciatic nerve.
Actions. The ham-string muscles flex the leg upon the thigh. "When the
knee is semi-flexed, the Biceps, in consequence of its oblique direction down-
wards and outwards, rotates the leg slightly outwards; and the Semimem-
branosus, in consequence of its oblique direction, rotates the leg inwards,
assisting the Popliteus. Taking their fixed point from below, these muscles
serve to support the pelvis upon the head of the femur, and to draw the trunk
directly backwards, as in feats of strength, when the body is thrown backwards
in the form of an arch.
Surgical Anatomy. The tendons of these mnscles occasionally require subcutaneous division
in some forms of spurious anchylosis of the knee-joint, dependent upon permanent contraction
and rigidity of the Flexor muscles, or from stiffeninq- of the ligamentous and other tissues s-rround-
ing the joint, the result of disease. This is effected by putting the tendon upon the stretch, and
inserting a narrow sharp-pointed knife between it and the skin : the cutting edge being then
turned towards the tendon it should be divided, taking care that the wound in the skin is not at
the same time enlarged.
Muscles and Fascia of the Leg.
Dissection (Fig. 283). The knee should be bent, a block placed beneath it, and the foot kept
in an extended position ; then make an incision through the integument in the middle line of I he
leg to the ankle, and continue it along the dorsum of the foot to the toes. Make a second incision
transversely across the ankle, and a third in the same direction across the bnses of the toes;
remove the flaps of integument included between these incisions, in order to examine the deep
fascia of the leg.
The Fascia of the Leg forms a complete investment to the whole of this region
of the limb, excepting to the inner surface of the tibia. It is continuous above
with the fascia lata, receiving an expansion from the tendon of the Biceps on
the outer side, and from the tendons of the Sartorius, Gracilis, and Semiten-
dinosus on the inner side ; in front it blends with the periosteum covering the
446
MUSCLES AND FASCIA.
Fig. 288.— Muscl
the
es of the Front of
Leff.
(l>ia\,
tibia and fibula ; below, it is continuous witli
the annular ligaments of the ankle. It is thick
and dense in the upper and anterior part of the
leg, and gives attachment, by its deep surface,
to the Tibialis anticus and Extensor longus
digitorum muscles; but thinner behind, where
it covers the- Gastrocnemius and Soleus mus-
cles. Its deep surface gives off, on the outer
side of the leg, two strong intermuscular septa,
which inclose the Peronei muscles, and separate
them from the muscles on the anterior and
posterior tibial rigions, and several smaller and
more slender processes, which inclose the
individual muscles in each region ; at the same
time a broad transverse intermuscular septum,
called the deep fascia of the leg, intervenes be-
tween the superficial and deep muscles in the
posterior tibio-fibular region.
Now remove the fascia by diviclino;' it in the same
direction as the integument, excepting opposite the
anlvle, where it should be left entire. Commence the
removal of the fascia from below, opposite tlio tendons,
and detach it in the line of direction of the muscular
fibres.
Muscles of the Leg.
These may be subdivided into three groups :
those on the anterior, those on the posterior,
and those on the outer side.
A
Anteeior Tibio-fibular Region".
Tibialis Anticus.
Extensor Proprius Pollicis.
Extensor Longus Digitorum.
Peroneus Tertius.
The Tibialis Anticus is situated on the outer
side of the tibia ; it is thick and fleshy at its
upper part, tendinous below. It arises from
the outer tuberosity and upper two-thirds of
the external surface of the shaft of the tibia;
from the adjoining part of the interosseous
membrane; from the deep surface of the fascia;
and from the intermuscular septum between it
and the Extensor longus digitorum ; the fibres
pass vertically downwards, and terminate in a
tendon, which is apparent on the anterior surface
of the muscle at the lower third of the leg.
After passing through the innermost compart-
ment of the anterior annular ligament, it is
inserted into the inner and under surface of the
internal cuneiform bone, and base of the meta-
tarsal l)onc of til e great too.
Relations. By its anterior surface, with the
fascia, and with the annnlar ligament. By its
posterior surface, with \\w. interosseous mem-
brane, tibia, ankle-joint, and inner side of the
ANTERIOR TIBIO-FIBULAR REGION. 447
tarsus : tliis surface also overlaps tlie anterior tibial vessels and nerve in the
upper part of the leg. Bj its inner surface^ with the tibia. By its outer surface^
with the Extensor longus digitorum, and Extensor proprius pollicis, and the
anterior tibial vessels and nerve.
The Extensor Projjrius Pollicis is a thin, elongated, and flattened muscle,
situated betAveen the Tibialis anticus and Extensor longus digitorum. It arises
from the anterior surface of the fibula for about the middle two-fourths of its
extent, its origin being internal to that of the Extensor longus digitorum ; it
also arises from the interosseous membrane to a similar extent. The fibres
pass downwards, and terminate in a tendon, which occupies the anterior border
of the muscle, passes through a distinct compartment in the horizontal portion
of the annular lio-ament, crosses the anterior tibial vessels near the bend of the
ankle, and is inserted into the base of the last phalanx of the great toe. Oppo-
site the metatarso- phalangeal articulation, the tendon gives off a thin prolonga-
tion on each side, which covers the surface of the joint.
Relations. By its anterior horder^ with the fascia, and the anterior annular
ligament. By its posterior harder^ with the interosseous membrane, fibula, tibia,
ankle-joint, and Extensor brevis digitorum. By its outer side, with the Extensor
longus digitorum above, the dorsalis pedis vessels and anterior tibial nerve below.
By its inner side, with the Tibialis anticus and the anterior tibial vessels above.
The Extensor Longus Digitorum is an elongated, flattened, semipenniform
muscle, situated the most externally of all the muscles on the forepart of the
leg. It arises from the outer tuberosity of the tibia; from the upper three-
fourths of the anterior surface of the shaft of the fibula ; from the interosseous
membrane, and deep surface of the fascia; and from the intermuscular septa
between it and the Tibialis anticus on the inner, and the Peronei on the outer
side. The muscle terminates in three tendons, which pass through a canal in
the annular ligament, with the Peroneus tertius, run across the dorsum of the
foot, and are inserted into the second and third phalanges of the four lesser
toes, the innermost tendon being subdivided into two. The mode in which the
tendons are inserted is the following: Each tendon opposite the metatarso-pha-
langeal articulation is joined, on its outer side, by the tendon of the Extensor
brevis digitorum (except the fourth), and receives a fibrous expansion from the
Interossei and Lumbricales ; it then spreads into a broad aponeurosis, which
covers the dorsal surface of the first phalanx: this aponeurosis, at the articu-
lation of the first with the second phalanx, divides into three slips, a middle
one, which is inserted into the base of the second phalanx ; and two lateral
slips, which, after uniting on the dorsal surface of the second phalanx, are
continued onwards, to be inserted into the base of the third.
Relations. By its anterior surface, with the fascia and the annular ligament.
By its 'posterior surface, with the fibula, interosseous membrane, ankle-joint, and
Extensor brevis digitorum. By its inner side, Avith the Tibialis anticus. Extensor
proprius pollicis, and anterior tibial vessels and nerve. By its outer side, with
the Peroneus longus and brevis.
The Peroneus Tertius is a part of the Extensor longus digitorum, and might
be described as its fifth tendon. The fibres belonging to this tendon arise from
the lower fourth of the anterior surface of the fibula, on its outer side ; from the
lower part of the interosseous membrane; and from an intermuscular septum
between it and the Peroneus brevis. The tendon, after passing through the
same canal in the annular ligament as the Extensor longus digitorum, is inserted
into the dorsal surface of the base of the metatarsal bone of the little toe, on
its inner side. This muscle is sometimes wanting.
Nerves. These muscles are supplied by the anterior tibial nerve.
Actions. The Tibialis anticus and Peroneus tertius are the direct flexors of
the tarsus upon the leg ; the former muscle, from the obliquity in the direction
of its tendon, raises the inner border of the foot ; and the latter, acting with the
Peroneus brevis and longus, Avill draw the outer border of the foot upwards,
448
MUSCLES AND FASCIA,
and the sole outwards. Tlie Extensor longus digitorum and Extensor proprius
pollicis extend the phalanges of the toes, and, continuing their action, flex the
tarsus upon the leg. Taking their fixed point from below, in the erect postu.re,
all these muscles serve to fix 1he bones of the leg in the perpendicular position,
and give increased strength to the ankle-joint.
Posterior Tibio-fibular Eegiok.
Dissection (Fig. 286). Make a vertical incision along the middle line of the back of the
leg, from the lower part of the popliteal space to the heel, connecting it below by a transverse
incision extending between the two malleoli; the flaps
of integument being removed, the fascia and muscles
should be examined.
Fig. 289.— Muscles of the Back of the
Leg. Superficial Layer.
The muscles in this region of the leg are
subdivided into two layers, superficial and
deep. The superficial layer constitutes a
powerful muscular mass, forming the calf of
the leg. Their large size is one of the most
characteristic features of the muscular appa-
ratus in man, and bears a direct connection
with his ordinary attitude and mode of pro-
gression.
Svperficial Layer.
Gastrocnemius. Soleus.
Plantaris.
The Gastrocnemius is the most superficial
muscle, and forms the greater part of the
calf. It arises by two heads, which are con-
nected to the condyles of the femur by two
strong flat tendons. The inner head, the
larger, and a little the more posterior, arises
from a depression at the upper and back part
of the inner condyle. The outer head arises
from the upper and back part of the external
condyle, immediately above the origin of the
Popliteus. Both heads, also, arise by a few
tendinous and fleshy fibres from the ridges
which are continued upwards from the con-
dyles to the linea aspera. Bach tendon
spreads out into an aponeurosis, which covers
the posterior surface of that portion of the
muscle to which it belongs; that covering
the inner head being longer and thicker than
the outer. From the anterior surface of these
tendinous expansions, muscular fibres are
given off. Tlie fibres in the median line,
which correspond to the accessory portions
of tlie muscle derived from the bifurcations
oC ihe linea aspera, unite at an angle upon a
median tendinous r«ph^ below ; the remaining
fil)res converge to the posterior surface of an
aponeurosis wliich covers the front of the
nnisclc, and 1his, gradually contracting, unites
will) the tend (Ml of the Soleus, and forms
with it the Tendo Achillis.
lielations. By its svperficial surface^ with
the fascia of the leg, which separates it 'from
POSTERIOE TIBIO-FIBULAR REGION. 449
the external saplienoiis vein and nerve. By its deep surface^ with the posterior
ligament of the knee-joint, the Popliteus, Soleus, Plantaris, popliteal vessels,
and internal popliteal nerve. The tendon of the inner head corresponds with
the back part of the inner condyle, from which it is separated by a synovial
bursa, which, in some cases, communicates with the cavity of the knee-joint.
The tendon of the outer head contains a sesamoid fibro-cartilage (rarely osseous),
where it plays over the corresponding outer condyle; and one is occasionally
found in the tendon of the inner head.
The Gastrocnemius should be divided across, just below its origin, and turned downwards, in
order to expose the next muscles.
The Soleus is a broad flat muscle situated immediately beneath the preceding.
It has received its name from its resemblance in shape to a sole-fish. It arises
by tendinous fibres from the back part of the head of the fibula, and from the
upper third of the internal surface of its shaft ; from the oblique line of the
tibia, and from the middle third of its internal border ; some fibres also arise
from a tendinous arch placed between the tibial and fibular origins of the muscle,
beneath which the posterior tibial vessels and nerve pass. The fibres pass
backwards to an aponeurosis which covers the posterior surface of the muscle,
and this, gradually becoming thicker and narrower, joins with the tendon of the
Gastrocnemius, and forms with it the Tendo Acliillis.
Relations. By its superficial surface^ with the Gastrocnemius and Plantaris.
By its deep surface^ with the Flexor longus digitorum. Flexor longus poUicis,
Tibialis posticus, and posterior tibial vessels and nerve, from which it is sepa-
rated by the transverse intermuscular septum or deep fascia of the leg.
The Tendo AchiUis, the common tendon of the Gastrocnemius and Soleus, is
the thickest and strongest tendon in the body. It is about six inches in length,
and formed by the junction of the aponeurosis of the two preceding muscles.
It commences about the middle of the leg, but receives fleshy fibres on its ante-
rior surface, nearly to its lower end. Gradually becoming contracted below, it
is inserted into the lower part of the posterior tuberosity of the os calcis, a
synovial bursa being interposed between the tendon and the upper part of the
tuberosity. The tendon spreads out somewhat at its lower end, so that its
narrowest part is usually about an inch and a half above its insertion. The
tendon is covered by the fascia and the integument, and is separated from the
deep muscles and vessels by a considerable interval filled up with areolar and
adipose tissue. Along its outer side, but superficial to it, is the external saphe-
nous vein.
The Plantaris is an extremely diminutive muscle, placed between the Gastro-
cnemius and Soleus, and remarkable for its long and delicate tendon. It arises
from the lower part of the outer bifurcation of the linea aspera, and from the
posterior ligament of the knee-joint. It forms a small fusiform belly, about two
inches in length, terminating in a long slender tendon which crosses obliquely
between the two muscles of the calf, and running along the inner border of the
tendo Acliillis, is inserted with it into the posterior part of the os calcis. This
muscle is occasionally double, and is sometimes wanting. Occasionally its tendon
is lost in the internal annular ligament, or in the fascia of the leg.
Nerves. These muscles are supplied by the internal popliteal nerve.
Actions. The muscles of the calf possess considerable power, and are con-
stantly called into use in standing, walking, dancing, and leaping ; hence the
large size they usually present. In walking, these muscles draw powerfully
upon the os calcis, raising the heel, and with it, the entire body, from the ground ;
the body being thus supported on the raised foot, the opposite limb can be
carried forwards. In standing, the Soleus, taking its fixed point from below,
steadies the leg upon the foot, and prevents the body from falling forwards, to
which there is a constant tendency from the superincumbent weight. The Gas-
trocnemius, acting from below, serves to flex the femur upon the tibia assisted
• 29
450
MUSCLES AND FASCIA.
by tlie Popliteus. The Plantaris is the rudiment of a large muscle which exists
in some of the lower animals, and serves as a tensor of the plantar fascia.
Dee'p Layer.
Popliteus,
Flexor Longus Pollicis.
Flexor Longus Digitorum.
Tibialis Posticus.
Fig. 290.— Muscles of the Back of
the Leg. Peep Layers.
Dissection. Detach the Soleus from its attachment to
the fibula and tibia, and turn it downwards, when the deep
layer of muscles is exposed, covered by the deep fascia of
the leg.
The Deep Fascia of the leg is a broad, trans-
verse, intermuscular septum, interposed between
the superficial and deep muscles in the posterior
tibio-fibular region. On each side it is connected
to the margins of the tibia and fibula. Above
where it covers the Popliteus, it is thick and
dense, and receives an expansion from the ten-
don of the Semimembranosus; it is thinner in
the middle of the leg ; but below, where it
covers the tendons passing behind the malleoli,
it is thickened. It is continued onwards in the
interval between the ankle and the heel, where
it covers the vessels, and is blended with the
internal annular ligament.
This fascia should now be removed, commencing from
below opposite the tendons, and detaching it from the
muscles in the direction of their fibres.
The Popliteus is a thin, flat, triangular muscle,
which forms part of the floor of the popliteal
space, and is covered by a tendinous expansion,
derived from the Semimembranosus muscle. It
arises by a strong flat tendon about an inch in
length, from a deep depression on the outer side
of the external condyle of the femur, and from
the posterior ligament of the knee-joint ; and is
inserted into the inner two-thirds of the tri-
angular surface above the oblique line on the
posterior surface of the shaft of the tibia, and
into the tendinous expansion covering the sur-
face of the muscle. The tendon of the muscle
is covered by that of the Biceps and the external
lateral ligament of the knee-joint ; it grooves
the outer surface of the external scmihiuar carti-
lage, and is invested by the synovial nicmbrauo
of the knee-joint.
Relations. By its superficial surface, with the
fascia above mentioned, which separates it from
the Gastrocnemius, Plantaris, popliteal vessels,
and internal popliteal nerve. By its deep sur-
face, with the superior tibio-fibular nrticulatiou,
and back of the tibia.
The Flexor Lonf/its Pollicis is situated on the
fibular side of the leg, and is the most super-
ficial and largest of the next three muscles. It
arises from tlie lower two-thirds of the internal
surface of the shaft of the fil)ula, with the ex-
POSTERIOR TIBIO-FIBULAR REGION. 451
ception of an inch at its lowest part; from tlie lower part of tlie interosseous
membrane ; from an intermuscular septum between it and the Peronei, exter-
nally ; and from the fascia covering the Tibialis posticus. The fibres pass
obliquely downwards and backwards, and terminate round a tendon which
occupies nearly the whole length of the posterior surface of the muscle. This
tendon passes through a groove on the posterior surface of the tibia, external to
that for the Tibialis posticus and Flexor longus digitorum ; it then passes through
another groove on the posterior extremity of the astragalus, and along a third
groove, beneath the lesser process of the os calcis, into the sole of the foot, where
it runs forwards between the two heads of the Flexor brevis poUicis, and is
inserted into the base of the last phalanx of the great toe. The grooves in the
astragalus and os calcis which contain the tendon of the muscle, are converted
by tendinous fibres into distinct canals, lined by synovial membrane ; and as
the tendon crosses the sole of the foot, it is connected to the common flexor by a
tendinous slip.
Relations. By its superficial surf ace ^ with the Soleas and Tendo Achillis, from
which it is separated by the deep fascia. By its deep surface^ with the fibula.
Tibialis posticus, the peroneal vessels, the lower part of the interosseous mem-
brane, and the ankle-joint. By its outer horder^ with the Peronei. By its inner
harder^ with the Tibialis posticus, and Flexor longus digitorum.
The Flexor Longus Digitorum (^perforans) is situated on the tibial side of the
leg. At its origin, it is thin and pointed, but gradually increases in size as it
descends. It arises from the posterior surface of the shaft of the tibia imme-
diately below the oblique line, to within three inches of its extremity internal
to the tibial origin of the Tibialis posticus ; some fibres also arise from the inter-
muscular septum between it and the Tibialis posticus. The fibres terminate in
a tendon, which runs nearly the whole length of the posterior surface of the
muscle. This tendon passes, behind the malleolus, in a groove, common to it
and the Tibialis posticus, but separated from the latter by a fibrous septum ;
each tendon being contained in a special sheath lined by a separate synovial
membrane. It then passes obliquely forwards and outwards beneath the arch
of the os calcis, into the sole of the foot (Fig. 292), where, crossing beneath the
tendon of the Flexor longus pollicis, to which it is connected by a strong tendi-
nous slip, it becomes expanded, is joined by the Flexor aceessorius, and finally
divides into four tendons which are inserted into the bases of the last phalanges
of the four lesser toes, each tendon passing through a fissure in the tendon of
the Flexor brevis digitorum opposite the middle of the first phalanges.
Relations. In the leg: by its superficial surface^ with the Soleus, and the
posterior tibial vessels and nerve, from which it is separated by the deep fascia ;
by its deep surf ace^ with the tibia and Tibialis posticus. In the foot ^ it is covered
by the Abductor pollicis and Flexor brevis digitorum, and crosses beneath the
Flexor longus pollicis.
The Tibialis Posticus lies between the two preceding muscles, and is the most
deeply seated of all the muscles in the leg. It commences above by two pointed
processes, separated by an angular interval, through which the anterior tibial
vessels pass forwards to the front of the leg. It arises from the whole of the
posterior surface of the interosseous membrane, excepting its lowest part, from
the posterior surface of the shaft of the tibia, external to the Flexor longus
digitorum, between the commencement of the oblique line above, and the middle
of the external border of the bone below, and from the upper two-thirds of the
inner surface of the shaft of the fibula ; some fibres also arise from the deep
fascia, and^from the intermuscular septa, separating it from the adjacent muscles
on each side. This muscle, in the lower fourth of the leg, passes in front of the
Flexor longus digitorum, terminates in a tendon, which passes through a groove
behind the inner malleolus, with the tendon, of that muscle, but inclosed in a
separate sheath ; it then passes through another sheath, over the internal lateral
ligament and beneath the calcaneo -scaphoid articulation, and is inserted into the
452 MUSCLES AND FASCIA.
tuberosity of the scaplioid, and internal cuneiform bones. The tendon of this
muscle contains a sesamoid bone, near its insertion, and gives off fibrous expan-
sions, one of wliicb passes backwards to the os calcis, others outwards to the
middle and external cuneiform, and some forwards to the bases of the third and
fourth metatarsal bones (Fig. 293).
Relations. By its superficial surface^ with the Soleus, and Flexor longus digi-
torum, the posterior tibial vessels and nerve, and the peroneal vessels, from
which it is separated by the deep fascia. By its deep surface^ with the inter-
osseous ligament, the tibia, fibula, and ankle-joint.
Nerves. The Poplitens is supplied by the internal popliteal nerve, the re-
maining muscles of this group by the posterior tibial nerve.
Actions. The Popliteus assists in flexing the leg upon the thigh ; when the
leg is flexed, it will rotate the tibia inwards. The Tibialis posticus is a direct
extensor of the tarsus upon the leg ; acting in conjunction with the Tibialis
anticus, it turns the sole of the foot inwards, antagonizing the Peroneus longus,
which turns it outwards. The Flexor longus digitorum and Flexor longus
poUicis are the direct Flexors of the phalanges, and, continuing their action,
extend the foot upon the leg ; they assist the Gastrocnemius and Soleus in ex-
tending the foot, as in the act of walking, or in standing on tiptoe. In conse-
quence of the oblique direction of the tendon of the long flexor, the toes would
be drawn inwards, were it not for the Flexor accessorius muscle, which is inserted
into the outer side of that tendon, and draws it to the middle line of the foot
during its action. Taking their fixed point from the foot, these muscles serve
to maintain the upright posture, by steadying the tibia and fibula, perpendicu-
larly, upon the ankle-joint. They also serve to raise these bones from the oblique
position they assume in the stooping posture.
Fibulae Eegion".
Peroneus Longus. Peroneus Brevis.
Dissection. These muscles are readily exposed, by removing the fascia covering their surface,
from below upwards, in the line of direction of their fibres.
The Peroneus Longus is situated at the upper part of the outer side of the leg,
and is the more superficial of the two muscles. It arises from the head, and
upper two-thirds of the outer surface of the shaft of the fibula, from the deep
surface of the fascia, and from the intermuscular septa, between it and the
muscles on the front, and those on the back of the leg. It terminates in a long
tendon, which passes behind the outer malleolus, in a groove common to it and
the Peroneus brevis, the groove being converted into a canal by a fibrous band,
and the tendons invested by a common synovial membrane ; it is then reflected,
obliquely forwards, across the outer side of the os calcis, being contained in a
separate fibrous sheath, lined by a prolongation of the synovial membrane from
that which lines the groove behind the malleolus. Having reached the outer
side of the cub(;id bone, it runs in a groove on the under surface of tliat bone,
which is converted into a canal by the long calcaneo-cuboid ligament, and is lined
by a synovial membrane : the tendon then crosses obliquely the sole of the foot
and is inserted into the outer side of the base of the metatarsal bone of the great
toe. The tendon changes its direction at two points : first, behind the external
malleolus; secondly, on the outer side of the cuboid bone ; in both of these sit-
uations, tlie tendon is thickened, and, in the latter, a sesamoid bone is usually
developed in its substance.
ReXationa. By its swperficial surface^ with the fascia and integument ; by its
deep surface^ with the fibula, the Peroneus brevis, os calcis, and cuboid bone ; by
its anterior horder^ with an intermuscular septum, Avhicli intervenes between it
and tlie Extensor longus digitorum ; by \i^ posterior horder^ with an intermuscular
OF THE FOOT. 453
septum, wliicli separates it from the Soleus above, and tlie Flexor longus pollicis
below.
The Peroneus Brevis lies beneath the Peroneus longus and is shorter and
smaller than it. It arises from the middle third of the external surface of the
shaft of the fibula, internal to the Peroneus longus ; from the anterior and poste-
rior borders of the bone ; and from the intermuscular septa separating it from
the adjacent muscles on the front and back part of the leg. The fibres pass
vertically downwards, and terminate in a tendon, which runs in front of that of
the preceding muscle through the same groove, behind the external malleolus,
being contained in the same fibrous sheath, and lubricated by the same synovial
membrane ; it then passes through a separate sheath on the outer side of the os
calcis, above that for the tendon of the Peroneus longus, and is finally inserted
into the dorsal surface of the base of the metatarsal bone of the little toe, on its
outer side.
Relations. By its superficial surface^ with the Peroneus longus and the fascia
of the leg and foot. By its deep surface^ with the fibula and outer side of the
OS calcis.
Nerves. The Peroneus longus and brevis are supplied by the musculo-cuta-
neous branch of the external popliteal nerve.
Actions. The Peroneus longus and brevis extend the foot upon the leg, in
conjunction with the Tibialis posticus, antagonizing the Tibiahs anticus and Pero-
neus tertius, which are flexors of the foot. The Peroneus longus also everts the
sole of the foot ; hence the extreme eversion occasionally observed in fracture
of the lower end of the fibula, where that bone ofiJers no resistance to the action
of this muscle. Taking their fixed point below, the Peronei serve to steady
the leg upon the foot. This is especially the case in standing upon one leg, when
the tendency of the superincumbent weight is to throw the leg inwards: the
Peroneus longus overcomes this tendency, by drawing on the outer side of the
leg, and thus maintains the perpendicular direction of the limb.
Surgical Anatomy. The student should now consider the position of the tendons of the
various muscles of the leg, their relation with the ankle-joint and surrounding bloodvessels, and
especially their action upon the foot, as their rigidity and contraction give rise to one or other of
the kinds of deformity known as dub-foot. The most simple and common deformity, and one
that is rarely, if ever, congenital, is the talipes equinus, the heel being raised by rigidity and
contraction of the Gastrocnemius muscle, and the patient walking upon the ball of the foot. In
the talipes varus, which is the more common congenital form, the heel is raised by the Tendo
Achillis, the inner border of the foot drawn upwards by the Tibialis anticus, and the anterior two-
thirds of the foot twisted inwards by the Tibialis posticus and Flexor longus digitorum, the
patient walking upon the outer edge of the foot, and in severe cases upon the dorsum and outer ankle.
In the talipes valgus, the outer edge of the foot is raised by the Peronei muscles, and the patient
walks ou the inner ankle. In the talipes calcaneus the toes are raised by the Extensor muscles,
the heel is depressed, and the patient walks upon it. Other varieties of deformity are met with,
as the talipes equino-varus, equino-valgus, and calcaneo-valgus, whose names sufficiently indi-
cate their nature. Each of these deformities may be successfully relieved (after other remedies
fail) by division of the opposing tendons and fascia : by this means, the foot regains its proper
position, and the tendons heal by the organization of lymph thrown out between the divided ends.
The operation is easily performed by putting the contracted tendon upon the stretch, and dividing
it by means of a narrow sharp-pointed knife inserted between it and the skin.
Muscles and Fascia of the Foot,
The fibrous bands which bind down the tendons in front of and behind the ankle in their
passage to the foot, should now be examined ; they are termed the annular ligaments, and are
three in number, anterior, internal, and external.
The Anterior Annular Ligament consists of a superior or vertical portion,
which binds down the extensor tendons as they descend on the front of the tibia
and fibula ; and an inferior or horizontal portion, which retains them in connec-
tion with the tarsus, the two portions being connected by a thin intervening
layer of fascia. The vertical portion is attached externally to the lower end of
the fibula, internally to the tibia, and above is continuous with the fascia of the
454 MUSCLES AND FASCIA.
leg ; it contains two separate slieaths, one internally, for the tendon of tlie Tibi-
alis anticus, one externally, for the tendons of the Extensor longus digitornm
and Peroneus tertius; the tendon of the Extensor proprius pollicis, and the ante-
rior tibial vessels and nerve pass beneath it, but without any distinct sheath.
The horizontal portion is attached externally to the upper surface of the os
calcis, in front of the depression for the interosseous ligament, and internally to
the inner malleolus and plantar fascia : it contains three slieaths ; the most in-
ternal for the tendon of the Tibialis anticus, the next in order for the tendon of
the Extensor proprius pollicis, and the most external for the Extensor longus
digitornm and Peroneus tertius: the anterior tibial vessels and nerve lie alto-
gether beneath it. These sheaths are lined by separate synovial membranes.
The Internal Annular Ligament is a strong iibrous band, which extends from
the inner malleolus above, to the internal margin of the os calcis below, con-
verting a series of bony grooves in this situation into osseo-fibrous canals, for
the passage of the tendons of the Flexor muscles and vessels into the sole of
the foot. It is continuous above with the deep fascia of the leg, below with the
plantar fascia and the fibres of origin of the Abductor pollicis muscle. The
three canals which it forms, transmit from within outwards, first, the tendon of
the Tibialis posticus; second, the tendon of the Flexor longus digitornm, then
the posterior tibial vessels and nerve, which run through a broad space beneath
the ligament : lastly, in a canal formed partly by the astragalus, the tendon of
the Flexor longus pollicis. Each of these canals is lined by a separate synovial
membrane.
The External Annular Ligament extends from the extremity of the outer
malleolus to the outer surface of the os calcis : it binds down the tendons of the
Peronei muscles in their passage beneath the outer angle. The two tendons are
inclosed in one synovial sac.
Dissection of the Sole of the Foot. The foot sliould be placed on a high block with the sole
uppermost, and firmly secured in that position. Carry an incision round the heel and along the
inner and outer borders of the foot to the great and little toes. This incision should divide the
integument and thick layer of granular fat beneath, until the fascia is visible ; the skin and fat
should then be removed from the fascia in a direction from behind forwards, as seen in Fig. 186.
The Plantar Fascia, the densest of all the fibrous membranes, is of great
strength, and consists of dense pearly-white glistening fibres, disposed, for the
most part, longitudinally : it is divided into a central and two lateral portions.
The central portion, the thickest, is narrow behind and attached to the inner
tubercle of the os calcis, behind the origin of the Flexor brevis digitornm, and
becoming broader and thinner in front, divides opposite the middle of the meta-
tarsal bones into five processes, one for each of the toes. Each of these processes
divides opposite the metatarso-phalangcal articulation into two slips, which
embrace the sides of the flexor tendons of the toes, and are inserted into the sides
of the metatarsal bones, and into the transverse metatarsal ligament, thus forming
a series of arches through which the tendons of the short and long flexors pass
to the toes. The intervals left between the five processes allow the digital
vessels and nerves, and the tendons of the Lumbricales muscles, to become super-
ficial. At the point of division of the fascia into processes and slips, numerous
transverse fibres are superadded, which serve to increase the strength of the
fascia at this part, by binding the processes together, and connecting them with
the integument. The central portion of the plantar fascia is continuous with
the lateral portions at eacli side, and sends upwards into the foot, at their point
of junction, two strong vortical intermuscular septa, brondcr in front than boliind,
whicli separate the middle from the external and internal plantar group of
muscles; from these again thinner transverse septa arc derived, which separate
the various layers of muscles in this region. The upper surface of this fascia
gives attachment behind to the Flexor brevis digitornm muscle.
The lateral portions of the ])lantar fascia are thinner than the central piece
and cover the sides of the foot.
OF THE FOOT. 455
The outer 'portion covers tlie under surface of the Abductor minimi digiti; it
is thick behmd, thin in front, and extends from the os calcis forwards to the
base of the fifth metatarsal bone, into the outer side of which it is attached ; it
is continuous internally with the middle portion of the plantar fascia, and
externally with the dorsal fascia.
The inner portion is very thin, and covers the Abductor poUicis muscle ; it is
attached behind to the internal annular ligament, and is continuous around the
side of the foot with the dorsal fascia, and externally with the middle portion
of the plantar fascia.
Muscles of the Foot.
These are found in two regions: 1. On the dorsum; 2. On the plantar surface.
1. DOESAL EeGIOINT.
Extensor Brevis Digitorum.
The Fascia on the dorsum of the foot is a thin membranous layer, continuous
above with the anterior margin of the annular ligament; it becomes gradually
lost opposite the heads of the metatarsal bones, and on each side blends with
the lateral portions of the plantar fascia; it forms a sheath for the tendons
placed on the dorsum of the foot. On the removal of this fascia, the muscles
and tendons of the dorsal region of the foot are exposed.
The Extensor Brevis Digitorum (Fig. 288) is a broad thin muscle, which arises
from the outer side of the os calcis, in front of the groove for the Peroneus
brevis ; from the external calcaneo-astragaloid ligament ; and from the hori-
zontal portion of the anterior annular ligament. It passes obliquely across the
dorsum of the foot, and terminates in foar tendons. The innermost, which is
the largest, is inserted into the first phalanx of the great toe, crossing the
dorsalis jiedis artery ; the other three, into the outer sides of the long extensor
tendons of the second, third, and fourth toes.
Retations. By its superficial surface^ with the fascia of the foot, the tendons
of the Extensor longus digitorum and Extensor proprius pollicis. By its deep
surface, with the tarsal and metatarsal bones, and the Dorsal interossei muscles.
Nerves. It is supplied by the anterior tibial nerve.
Actions. The Extensor brevis digitorum is an accessory to the long Extensor,
extending the phalanges of the four inner toes, but acting only on the first
phalan'x of the great toe. The obliquity of its direction counteracts the oblique
movement given to the toes by the long Extensor, so that, both muscles acting
together, the toes are evenly extended.
2. Plantar Region.
The. muscles in the plantar region of the foot may be divided into three
groups, in a similar manner to those in the hand. Those of the internal plantar
region are connected with the great toe, and correspond with those of the thumb ;
those of the external plantar region, are connected with the little toe, and corre-
spond with those of the little finger; and those of the middle plantar region are
connected with the tendons intervening between the two former groups. But
in order to facilitate the dissection of these muscles, it will be found more
convenient to divide them into four layers, as they present themselves, in the
order in which they are successively exposed.
456
MUSCLES AND FASCIiE.
Fig. 291.— Muscles of the Sole of the
Foot. First Layer.
First Layer.
Abductor PoUicis. Flexor Brevis Digitorum.
Abductor Minimi Digiti.
Dissection. Eemove the fascia on the inner and outer sides of the foot, commencing in front
over the tendons, and proceeding backwards. The central portion should be divided transversely
in the middle of the foot, and the two flaps dissected forwards and backwards.
The Abductor PoUicis lies along tlie inner border of the foot. It arises from
the inner tubercle on the under surface of the os calcis ; from the internal
g,nnular ligament; from the plantar fascia;
and from the intermuscular septum between
it and the Flexor brevis digitorum. The
fibres terminate in a tendon, which is inserted,
together with the innermost tendon of the
Flexor brevis pollicis, into the inner side of
the base of the first phalanx of the great toe.
It is supplied by the internal plantar nerve.
Relations. By its superficial surface, with
the plantar fascia. By its deep surface.^ with
the Flexor brevis pollicis, the Flexor acces-
sorius, and the tendons of the Flexor longus
digitorum and Flexor longus pollicis, the
Tibialis anticus and posticus, the plantar
vessels and nerves, and the articulations of
the tarsus.
The Flexor Brevis Digitorum (^perforatus)
lies in the middle of the sole of the foot,
immediately beneath^ the plantar fascia, with
which it is firmly united. It arises by a nar-
row tendinous process, from the inner tubercle
of the OS calcis, from the central part of the
plantar fascia; and from the intermuscular
septa between it and the adjacent muscles.
It passes forwards, and divides into four ten-
dons. Opposite the middle of the first pha-
langes, each tendon presents a longitudinal
slit, to allow of the passage of the correspond-
ing tendon of the Flexor longus digitorum;
the two portions form a groove for the recep-
tion of that tendon. The tendon of the short
flexor then reunites and immediately divides
a second time into two processes, which are
inserted into the sides of the second phalanges.
The mode of division of the tendons of the
Flexor brevis digitorum, and their insertion
into the phalanges, is analogous to the Flexor
sublimis in the hand. It is su]-)plied by the
internal ]")lantar nerve.
Relations. By its superficial surface, with
the ]ilantar fascia. By its deep surface, with
the Flexor acccssorius, the Lumbricales, the
tendons of the Flexor longus digitorum, and the external plantar vessels^ and
nerve, from which it, is separated by a thin layer of fascia. The oiiter and inner
horders arc sepanitcd \'r()\n. the adjacent muscles hy means of vertical prolonga-
tions of the plantar fascia.
Ill the (Tt^ct j)()silion, this would, of course, be above.
OF THE SOLE OF THE FOOT. SECOND LAYER.
457
Muscles of the Sole of the Foot.
Second Layer.
Tlie Ahductor Minimi Digiti lies along tlie outer border of tlie foot. It arises,
bj a very broad origin, from tlie outer tubercle of the os calcis, from tbe under
surface of tlie os calcis in front of the tubercle, from the plantar fascia, and the
intermuscular septum between it and the
Flexor brevis digitorum. Its tendon. Fig. 292.-
after gliding over a smooth facet on the
under surface of the base of the fifth meta-
tarsal bone, is inserted with the short
Flexor of the little toe into the outer side
of the base of the first phalanx of the
little toe. It is supplied by the external
plantar nerve.
Relations, By its superficial surface^
with the plantar fascia. By its deep
surface^ with the Flexor accessorius, the
Flexor brevis minimi digiti, the long
plantar ligament, and the tendon of the
Peroneus longus. On its inner side are
the external plantar vessels and nerve,
and it is separated from the Flexor brevis
digitorum by a vertical septum of fascia.
Dissection. The muscles of the superficial layer
should be divided at their origin, by inserting the
knife beneath each, and cutting obliquely back-
wards, so as to detach them from the bone ; they
should then be drawn forwards, in order to expose
the second layer, but not cut away at their inser-
tion. The two layers are separated by a thin
membrane, the deep plantar fascia, on the removal
of which is seen the tendon of the Flexor longus
digitorum, the Flexor accessorius, the tendon of the
Flexor longus pollicis. and the Lumbricales. The
long flexor tendons cross each other at an acute
angle, the Flexor longus pollicis running along the
inner side of the foot, on a plane superior to that
of the Flexor longus digitorum, the direction of
which is obliquely outwards.
Second Layer.
Flexor Accessorius.
Lumbricales.
The Flexor Accessorius arises by two
heads: the inner or larger, which is
muscular, being attached to the inner
concave surface of the os calcis, and to the
calcaneo scaphoid ligament; the outer
head, flat and tendinous, to the under surface of the os calcis, in front of its
outer tubercle, and to the long plantar ligament: the two portions join at an
acute angle, and are inserted into the outer margin and upper and under surfaces
of the tendon of the Flexor longus digitorum, forming a kind of groove, in
which the tendon is lodged. It is supplied by the external plantar nerve.
Relations. By its superficial surface., with the muscles of the superficial layer,
from which it is separated by the external plantar vessels and nerves. By its
deep surface., with the os calcis and long calcaneo-cuboid ligament.
The Lumbricales are four small muscles, accessory to the tendons of the
Flexor longus digitorum : they arise from the tendons of the long flexor, as far
back as their angle of division, each arising from two tendons, except the
internal one. Bach muscle terminates in a tendon, which passes forwards on
the inner side of each of the lesser toes, and is inserted into the expansion of the
458
MUSCLES AND FASCIA.
long extensor and base of the first phalanx of the corresponding toe. The two
internal Lumbricales muscles are supplied by the internal, and the two external
bj the external plantar nerve.
Dissection. The flexor tendons should be divided at the back part of tlie foot, and the Flexor
accessorius at its origin, and drawn forwards, in order to expose the third layer.
Flexor Brevis Pollicis.
Adductor Pollicis.
Third Layer.
Flexor Brevis Minimi Digiti.
Transversus Pedis.
Fig. 293.— Muscles of the Sole of the Foot.
Third Layer.
The Flexor Brevis Pollicis arises, by a
pointed tendinous process, from the inner
border of the cuboid bone, from the con-
tiguous portion of the external cunei-
form, and from the prolongation of the
tendon of the Tibialis posticus, which is
attached to that bone. The muscle
divides, in front, into two portions,
which are inserted into the inner and
outer sides of the base of the first phalanx
of the great toe, a sesamoid bone being
developed in each tendon at its insertion.
The inner portion of this muscle is
blended with the Abductor pollicis pre-
vious to its insertion, the outer with the
Adductor pollicis, and the tendon of the"
Flexor longus pollicis lies in a groove
between them.
Relations. By its superficial surface.^
with the Abductor pollicis, the tendon
of the Flexor longus poUices and plantar
fascia. By its c/eep surface., with the
tendon of the Peroneus longus, and meta-
tarsal bone of the great toe. By its
inner horder^ with the Abductor pollicis.
By its outer harder., with the Adductor
Pollicis.
The Adductor Pollicis is a large, thick,
fleshy mass, passing obliquely across the
foot, and occupying the hollow space
between the four outer metatarsal bones.
It arises from the tarsal extremities of
the second, third, and fourth metatarsal
bones, and from the sheath of the tendon
of the Peroneus longus, and is inserted,
together with the outer portion of the
Flexor brevis pollicis, into the outer side "
of the base of the first phalanx of the
groat toe.
The FlexoT Brevis Minimi Digiti lies
on the metatarsal bone of the little toe,
and much resembles one of the Inter-
ossei. It arises from the base of the metatarsal bone of the little toe, and from
the shcatli of the Peroneus loiigus; its tendon is inserted into the base of the
first ])halanx of the little toe on its outer side.
Relations. ]\y its superficial surface, with the ]>lan1ar fascia and tendon of the
Abductor minimi digiti. By its deep surface, with the fifth metatarsal bone.
OF THE SOLE OF THE FOOT. FOURTH LAYER.
459
Fig. 294.
The Dorsal Interossei.
Left Foot.
The Transversus Pedis is a narrow, flat, irmscular fasciculus, stretclied trans-
versely across the heads of the metatarsal bones, between them and the flexor
tendons. It arises from the under surface of the head of the fifth metatarsal
bone, and from the transverse ligament of the metatarsus ; and is inserted into
the outer side of the first phalanx of the great toe ; its fibres being blended
with the tendon of insertion of the Adductor
pollicis.
Nervous Supply. The Flexor brevis pollicis is
supplied by the internal plantar nerve, and some-
times (according to Meckel) receives a branch
from the external plantar. The other three mus-
cles of this layer are supplied by the external
plantar nerve.
Relations. By its under surface^ with the ten-
dons of the long and short Flexors and Lumbri-
cales. By its upper surface^ with the Interossei.
ft
Fourth Layer.
The Interossei.
The Interossei muscles in the foot are similar
to those in the hand, with this exception, that
they are grouped around the middle line of the
second toe, instead of the middle line of the whole
member, as in the hand. They are seven in
number, and consist of two groups, dorsal and
plantar.
The Dorsal Interossei^ four in number, are
situated between the metatarsal bones. They are
bipenniform muscles, arising by two heads from
the adjacent sides of the metatarsal bones between
which they are placed ; their tendons are inserted
into the bases of the first phalanges, and into the
aponeurosis of the common extensor tendon. In
the angular interval left between the heads of
each muscle at its posterior extremity, the per-
forating arteries pass to the dorsum of the foot ;
except in the first Interosseous muscle, where the
interval allows the passage of the communicating
branch of the dorsalis pedis artery. The first
Dorsal interosseous muscle is inserted into the
inner side of the second toe ; the other three are
inserted into the outer sides of the second, third,
and fourth toes. They are all abductors from the
middle line of the second toe.
The Plantar Interossei^ three in number, lie
beneath, rather than between, the metatarsal
bones. They are single muscles, and are each
connected with but one metatarsal bone. They
arise from the base and inner sides of the shaft
of the third, fourth, and fifth metatarsal bones,
and are inserted into the inner sides of the bases
of the first phalanges of the same toes, and into
the aponeurosis of the common extensor tendon.
These muscles are all adductors towards the
middle line of the second toe.
All the Interossei muscles are supplied by the
external plantar nerve.
Fi2:.295.-
-The Plantar Interossei.
Left Foot.
460
SURGICAL ANATOMY.
SUBGICAL ANATOMY.
Fig. 296.— Fracture of the Neck of the Femur within the
Capsular Ligament.
PYRirORMI
S
GEMELLUS
SUPERIOR
OBTURATOR IN7£RNUS
GEMELLUS
INFERIOR
OBTURATOR
EXTERNUa
QUADRATUS
PEMORIS
Fig. 297.— Fracture of the Fe-
mur below the Trochanters.
The student should now con-
sider the effects produced by
the action of the various muscles
in fractures of the bones of the
lower extremity. The more
common forms of fracture are
selected for illustration and de-
scription.
Fracture of the veck of the
femur internal to the capsular
ligament (Fig. 296) is a very
common accident, and is most
frequently caused by indirect
violence, such as slipping off
the edge of the curbstone, the
impetus and weight of the body
falling upon the neck of the
bone. It usually occurs in fe-
males, and seldom under fifty
years of age. At this period of
life, the cancellous tissue of the
neck of the bone not unfre-
quently is atrophied, becoming
soft and infiltrated with fatty
matter ; the compact tissue is
partially absorbed : hence the
bone is more brittle, and more
liable to fracture. The charac-
teristic marks of this accident
are slight shortening of the limb,
and eversion of the foot, neither
of which symptoms occurs, however, in some cases until some
time after the injury. The eversion is caused by the combined
action of the external rotator muscles, as well as by the Psoas
and Iliacus, Pectineus, Adductors, and Glutei muscles. The
shortening is produced by the action of the Glutei, and by the
Rectus femoris in front, and the Biceps, Semitendinosus, and
Semimembranosus behind.
Fracture of the femur just heloio the trochanters (Fig. 297)
is an accident of not unfrequent occurrence, and is attended
with great displacement, producing considerable deformity.
The upper fragment, the portion chiefly displaced, is tilted for-
wards almost at right angles with the pelvis, by the combined
action of the Psoas and Iliacus ; and, at the same time, everted
and drawn outwards by the external rotatcr and Glutei muscles,
causing a marked prominence at the upper and outer side of the
thigh, and much pain from the bruising and laceration of the
muscles. 'I'he limb is shortened, in consequence of the lower
fragment being drawn upwards by the Rectus in front, and the
Biceps, Semimembranosus, and Scmilendinosus behind ; and, at
the same time, everted, and the upper end thrown outwards, the
lower inwards, by the Pectineus and Adductor muscles. 'J'his
fracture may be reduced in two different methods: either by
direct relaxation of all the opposing muscles, to efl'ect which the
limb should Vjc placed on a double inclined plane; or by over-
coming the conlrnction of the muscles, by continued extension,
which may l)e effected by means of the long splint.
Oblif|ue fracture of the femur immedialely above the condyles
(Fi<r. 298) is a formidable injury, and attended with considerable
displacement. On examination of the liml), the lower fragment
may be felt deep in the jioplitcal space, being drawn backwards
Vjy the (iiistroctneinius and riaiitaris muscles, and ujiwards by
the posterior I'Vmoral and Rectus nniscles. 'I'hc pointed end of
the up])er frafrment is drawn inwards by the Pectineus and Ad-
ductor ninscles. and tilted forwards by the Psoas and Iliacus,
pierciufr the Rectus muscle, and occasionally, the integument.
Relaxation of these muscles and direct a))proximation of the
In-oken fragments are effected by placing the limb on a double
OF THE MUSCLES OF THE LOWER EXTREMITY.
461
inclined plane. The greatest care is requisite in keeping the pointed extremity of the upper
fragment in proper position ; otherwise, after union of the fracture, the power of extension of the
Fig. 298. — Fracture of the Femur above the Condyles. Fig. 299. — Fracture of the Patella.
Fig. 300.— Oblique Fracture of
the Shaft of the Tibia.
limb is partially destroyed, from the Rectus muscle being held down by the fractured end of the bone,
and from the patella, when elevated, being drawn upwards against the projecting fragment.
Fracture of the patella (Fig. 299) may be produced by mus-
cular action, or by direct violence. When produced by mus-
cular action, it occurs thus : a person in danger of falling
forwards attempts to recover himself by throwing the body
backwards, and the violent action of the Quadriceps extensor
upon the patella snaps that bone transversely across. The
upper fragment is drawn up the thigh by tlie Quadriceps ex-
tensor, the lower fragment being retained in its position by
the ligamentum patellae; the extent of separation of the two
fragments depending upon the degree of laceration of the
ligamentous structures around the bone. The patient is
totally unable to straighten the limb ; the prominence of the
patella is lost; and a marked but varying interval can be felt
between the fragments. The treatment consists in relaxing
the opposing muscles, which may be effected by raising the
trunk, and slightly elevating the limb, which should be kept
in a straight position. Union is usually ligamentous. In
fracture from direct violence, the bone is generally commi-
nuted, or fractured obliquely or perpendicularly.
Oblique fracture of the shaft of the tibia (Fig. 300) usually
occurs at the lower fourth of the bone, this being the narrowest
and weakest part, and is usually accompanied with fracture
of the fibula. If the fracture has taken place obliquely from
above, downwards, and forwards, the fragments ride over one
another, the lower fragments being drawn backwards and
upwards by the powerful action of the muscles of the calf; the
pointed extremity of the upper fragment projects forwards
immediately beneath the integument, often protruding through
it, and rendering the fracture a compound one. If the direc-
tion of the fracture is the reverse of that shown in the figure,
the pointed extremity of the lower fragment projects forwards,
riding upon the lower end of the upper one. By bending the
knee, which relaxes the opposing muscles, and making exten-
sion from the knee and ankle, the fragments may be brought
into apposition. It is often necessary, however, in compound
fractui-e, to remove a portion of the projecting bone with the
saw before complete adaptation can be effected.
Fracture of the fibula luith displacement of the tibia (Fig.
301), commonly known as " Pott's Fracture," is one of the most frequent injuries of the ankle-
joint. The end of the tibia is displaced from the corresponding surface of the astragalus ; the
462 SURGICAL ANATOMY.
internal lateral ligament is ruptured ; and the inner malleolus projects inwards beneath the in-
tegument, which is tightly stretched over it and in danger of bursting. The fibula is broken,
usually from two to three inches above the ankle, and occasionally that portion of the tibia with
which it is more directly connected below ; the foot is everted by the action of the Peroneus lon-
Fig. 301. — Fracture of the Fibula, with Dis]3lacement of the Tibia.—" Pott's Fracture."
A%1
gus, its inner border resting upon the ground, and, at the same time, the heel is drawn up by the
muscles of the calf, '^lliis injury may be at once reduced by flexing the leg at right angles with
the thigh, which relaxes all the opposing muscles, and by making slight extension from the knee
and ankle.
On the Descriptive Anatomy of the Muscles, refer to Cruveilhier's "Anatomic Descriptive ;"
"Traits de Myologie et d'Angeiologie," by F. G. Theile, Encyclopedic Anatomique, Paris,
1843 ; and Heule's " Handbuch der Systematischen Anatomic," before referred to.
Of the Arteries.
The Arteries are cylindrical tubular vessels, which serve to convey blood
from both ventricles of the heart to every part of the body. These vessels were
named arteries (a/Jp, air ; tyi?iCv^ to contain)^ from the belief entertained by the
ancients that they contained air. To Gralen is due the honor of refuting this
opinion ; he showed that these vessels, though for the most part empty after
death, contain blood in the living body.
The pulmonary artery, which arises from the right ventricle of the heart,
carries venous blood directly into the lungs, whence it is returned by the pulmo-
nary veins into the left auricle. This constitutes the lesser or pulmonic circu-
lation. The great artery which arises from the left ventricle, the aorta, conveys
arterial blood to the body generally ; whence it is brought back to the right side
of the heart by means of the veins. This constitutes the greater or systemic
circulation.
The distribution of the systemic arteries is like a highly ramified tree, the
common trunk of which, formed by the aorta, commences at the left ventricle of
the heart, the smallest ramifications corresponding to the circumference of the
body, and the contained organs. The arteries are found in nearly every part
of the body, with the exception of the hairs, nails, epidermis, cartilages, and
cornea ; and the larger trunks usually occupy the most protected situations, run-
ning, in the limbs, along the flexor side, where they are less exposed to injury.
There is considerable variation in the mode of division of the arteries : occa-
sionally a short trunk subdivides into several branches at the same point, as we
observe in the coeliac and thyroid axes ; or the vessel may give off several branches
in succession, and still continue as the main trunk, as is seen in the arteries of
the limbs ; but the usual division is dichotomous, as, for instance, the aorta divid-
ing into the two common iliacs ; and the common carotid, into the external and
internal.
The branches of arteries arise at very variable angles; some, as the superior
intercostal arteries from the aorta, arise at an obtuse angle ; others, as the lumbar
arteries, at a right angle ; or, as the spermatic, at an acute angle. An artery
from which a branch is given off is smaller in size, but retains a uniform dia-
meter until a second branch is derived from it. A branch of an artery is smaller
than the trunk from which it arises ; but if an artery divides into two branches,
the combined area of the two vessels is, in nearly every instance, somewhat
greater than that of the trunk ; and the combined area of all the arterial branches
greatly exceeds the area of the aorta ; so that the arteries collectively may be
regarded as a cone, the apex of which corresponds to the aorta ; the base to the
'■capillary system.
The arteries, in their distribution, communicate freely with one another, form-
ing what is called an anastoTnosis [ivd, between ; oro^a, mouth), or inosculation ;
and this communication is very free between the large as well as between the
smaller branches. The anastomoses between trunks of equal size are found where
great freedom and activity of the circulation are requisite, as in the brain ; here
the two vertebral arteries unite to form the basilar, and the two internal carotid
arteries are connected by a short communicating trunk ; it is also found in the
abdomen, the intestinal arteries having very free anastomoses between their
larger branches. In the limbs, the anastomoses are most frequent and of
largest size around the joints ; the branches of an artery above freely inoscu-
lating with branches from the vessels below ; these anastomoses are of consider-
(463)
464 ARTERIES.
able interest to tlie surgeon, as it is bjtlieir enlargement that a collateral circu-
lation is established after tlie application of a ligature to an artery for the cure
of aneurism. The smaller branches of arteries anastomose more frequently than
the larger ; and between the smallest twigs, these inosculations become so nume-
rous as to constitute a close network that pervades nearly every tissue of the body.
Throughout the body generally, the larger arterial branches pursue a perfectly
straight course ; but in certain situations they are tortuous ; thus, the facial artery
in its course over the face, and the arteries of the lips, are extremelj^ tortuous
in their course, to accommodate themselves to the movements of the parts. The
uterine arteries are also tortuous, to accommodate themselves to the increase of
size which the organ undergoes during pregnancy. Again, the internal carotid
and vertebral arteries, previous to their entering the cavity of the skull, describe
a series of curves, which are evidently intended to diminish the velocity of the
current of blood, by increasing the extent of surface over which it moves, and
adding to the amount of impediment which is produced by friction.
The arteries are dense in structure, of considerable strength, highly elastic, and
when divided, they preserve, although empty, their cylindrical form.
The minute structure of these vessels is described in the Introduction,
In the description of the arteries, we shall first consider the efferent trunk of
the systemic circulation, the aorta, and its branches ; and then the efferent trunk
of the pulmonic circulation, the pulmonary artery.
The Aorta.
The Aorta (dopi-^, arteria, magna) is the main trunk of a series of vessels,
which, arising from the heart, convey the red oxygenated blood to every part,
of the body for its nutrition. This vessel commences at the upper part of the
left ventricle, and after ascending for a short distance, arches backwards, to the
left side, over the root of the left lung, descends within the thorax on the left
side of the vertebral column, passes through the aortic opening in the Diaphragm,
and entering the abdominal cavity, terminates, considerably diminished in size,
opposite the fourth lumbar vertebra, where it divides into the right and left
common iliac arteries. Hence its subdivision into the arch of the aorta, the
thoracic aorta, and the abdominal aorta, ^ from the direction or position of its
parts.
Arch of the Aorta.
Dissection. In order to examine the arch of the aorta, open the thorax, by dividing the
cartilages of the ribs on each side of the sternum, raising this bone from below upwards, and
then sawing through the sternum on a level with its articulation with the clavicle. By this means,
the relations of the large vessels to the upper border of the sternum and root of the neck are
kept in view.
The Arch of the Aorta extends from the origin of the vessel at the upper part
of the left ventricle to the lower border of the body of the fourth dorsal vertebra.
At its commencement, it ascends behind the sternum, obliquely upwards and
forwards towards the right side, and opposite the u]-)pcr border of the second
costal cartilage of the right side, passes transversely from right to left, and from
before >)ackwards, to the left side of the third dorsal vertebra ; it then descends
upon the left side of the body of the fourth dorsal vertebra, at the lower border
of which it takes the name of thoracic aorta. The arch of the aorta describes a
cvirve, the convexity of which is directed upwards and to the right vside ; and it
is sitbdividcd, at the points where it changes its direction, so as to be described
in tlircc portions, the ascending, transverse, and descending ])ortions of the arch
of the a<;rta.
' Tlif-o portion^ of lho aorta would be bollor named Iriinsvorsc Moriii. dursnl norbi. and nlxlnm-
inal (jr luniliar uoila ; but 1 hesitate to introduce new niinics in place of those in universal use.
ARCH OF AORTA.
465
Ascending Paet of the Arch.
The ascending portion of tlie arcL. of tlie aorta is about two inclies in lengtli.
It commences at the upper part of the left ventricle, in front of the left auriculo-
ventricular orifice, and opposite the middle of the sternum on a line with its
junction to the third costal cartilage; it passes obliquely upwards in the direction
of the heart's axis, to the right side, as high as the upper border of the second
costal cartilage, describing a slight curve in its course, and being situated, when
distended, about a quarter of an inch behind the posterior surface of the sternum.
Fis- 302. — The Arch of the Aorta and its Branches.
SA Vagus
Recurrent Za ^ geal
Zefi '^oyits
leflT enie
I — Tkor J)uct
^\^'* _^ Fig. SOo-Pfew oftLBraTuJies
k
Zifl CoTOimry
A little above its commencement, it is somewhat enlarged, and presents three
small dilatations, called the sinuses of the aorta (sinuses of Valsalva), opposite
to which are attached the three semilunar valves, which serve the purpose of
preventing any regurgitation of blood into the cavity of the ventricle. A section
of the aorta opposite this part has a somewhat triangular figure ; but below the
attachment of the valves it is circular. This portion of the heart is contained
in the cavitv of the pericardium, and, together with the pulmonary arterv, is
30
466 ARTERIES.
invested in a tnbe of serous membrane, continued on to tliem from tlie surface
of the heart.
Relations. The ascending part of the arcli is covered at its commencement
by the trunk of the pulmonary artery and the riglit appendix auriculae, and,
higher up, is separated from tlie sternum by the pericardium, some loose areolar
tissue, and the remains of the thymus gland; hehind^ it rests upon the right
pulmonary vessels and root of the right lung. On the right side, it is in relation
with the superior vena cava and right auricle; on the left side, with the pulmo-
nary artery.
Plajs" of the Eelations of the Ascending Part of the Arch.
Jn Front.
Pulmonary artery.
Right appendix auriculse.
Pericardium.
Remains of thymus gland.
Right side. f \ Left side.
o • I Arch of Aorta.\ -j, , ,
bupenor cava. Ascending I Pulmonary artery.
Riglit auricle.
Behind.
* Right pulmonary vessels.
Root of right lung.
Transverse Part of the Arch.
The second or transverse portion of the arch commences at the upper border
of the second chondro-sternal articulation of the right side in front, and passes
from right to left, and from before backwards, to the left side of the third dorsal
vertebra behind.^ Its upper border is usually about an inch below the upper
margin of the sternum.
Relations. Its anterior surface is covered by the left pleura and lung, and
crossed towards the left side by the left pneumogastric and phrenic nerves, and
' As regards the portion of the dorsal spine with which the transverse part of the arch of the
aorta is in contact, [ am indebted to Mr. Bennett, late Demonstrator of Anatomy at St. George's
Hospital, for the following observation : —
"in twelve subjects examined successively in i\\^, post-mortem room of the Hospital, in whom
the vessels were healthy, the following was the result as regards the highest point on the verte-
bral column touched by the arch of the aorta. In nine it was opposite some part of the third
dorsal vertebra: in one opposite the disk between the third and fourth, in one opposite the disii
between the second and third, and in one opposite the second dorsal vertebra."
Mr. J. Wood gives the following account of the relations and extent of the arch of the aorta,
as the result of his observations on thirty-two subjects, fourteen male and eighteen female, in
whom an antoro-posterior vertical section of the spinal colunni from top to bottom had been made,
with the viscera in situ.
The cardiac opening of the aorta lies in a horizontal plane drawn through the centre of the
third bone of tlie sternum, passing midway between the third and fdurth rib-cartilages, and
emerging behind about the tip of the sixth dorsal spinous process. The highest ])()int of the
aortic arch lies from three-quarters of an inch to an inch from the posterior surface of the second
bone of the sternum, close to its right border, and to the inner side of the joint between the
second right rib-cartilage and the; sternum. It approaches the; lower bo der of the left side of
the fourth dorsal vertebra, and first touches the spine usually about the intervertebral substance
between the fourth and fifth vertebra;. 1 1 tlnn assumes a more vertical direction, and lies
against the left sidt; of the body of tli(^ lilili dursal vertebra, which is, in fact, the uppermost
vertebra which shows on its body tin; impressidii or llatlcning prdduced by contact with the aorta
{Jnv.rn. of Anat. and Phi/s., vol. iii.).
This anatomist nccordingly puts the lower two portions of the arch one vertebra lower than
the account in the text, and he supports his observations l»y those of Pirogoif.
ARCH OF AORTA.
467
cardiac brandies of the sympatlietic. Its posterior surface lies on tlie tracliea,
just above its bifurcation, on the great, or deep, cardiac plexus, the oesophagus,
thoracic duct, and left recurrent laryngeal nerve. Its up^oer border is in relation
with the left innominate vein ; and from its upper part are given off the innomi-
nate, left common carotid, and left subclavian arteries. Its lower horder is in
relation with the bifurcation of the pulmonary artery, and the remains of the
ductus arteriosus, which is connected with the left division of that vessel; the
left recurrent laryngeal nerve winds round it from before backwards, whilst the
left bronchus passes below it.
Plan of the Eelations of the Transverse Part of the Arch,
Ahove.
Left innominate vein.
Arteria iunominata.
Left carotid.
Left subclavian.
In Front.
Left pleura and lung.
Left pneumogastric nerve.
Left phrenic nerve.
Cardiac nerves.
Behind.
Trachea.
Deep cardiac plexus,
ffisopliagus.
Thoracic duct.
Left recurrent nerve.
Beloio.
Bifurcation of pulmonary artery.
Remains of ductus arteriosus.
Left recurrent nerve.
Left bronchus.
Descending Part of the Arch.
The descending portion of the arch has a straight direction, inclining down-
wards on the left side of the body of the fourth dorsal vertebra, at the lower
border of which it takes the name of thoracic aorta.
Relatiojis. Its anterior surface is covered by the pleura and root of the left
lung; behind., it lies on the left side of the body of the fourth dorsal vertebra.
On its right side are the oesophagus and thoracic duct ; on its left side it is
covered by the pleura.
Plan of the Relations of the Descending Part of the Arch.
In Front.
Pleura.
Root of left lung.
Right side.
(Esophagus.
Thoracic duct.
Left side.
Pleura.
Beh in d.
Left side of body of fourth dorsal vertebra.
The ascending, transverse, and descending portions of the arch vary in position
according to the movements of respiration, being lowered, together with the
trachea, bronchi, and pulmonary vessels, during inspiration by the descent of the
Diaphragm, and elevated during expiration, when the Diaphragm ascends.
These movements are greater in the ascending than the transverse, and in the
latter than the descending part.
468 ARTERIES.
Pecuh'cirit>es. The height to wliich the aorta rises in the chest is usually about an inch below
the upper border of the sternum ; but it may ascend nearly to the top of that bone. Occasion-
ally, it is found an inch and a half, more rarely three inches below this point.
In direction. Sometimes the aorta arches over the root of the right instead of the left lung,
as in birds, and passes down on the right side of the spine. In such cases all the viscera of the
thoracic and abdominal cavities are transposed. Less frequently, the aorta, after arching over
the root of the right lung, is directed to its usual position on the left side of the spine, this pecu-
liarity not being accompanied by any transposition of the viscera.
In coit formation. The aorta occasionally divides, as in some quadrupeds, into an ascending
and a descending trunk, the former of which is directed vertically upwards, and subdivides into
three branches, to supply the head and upper extremities. Sometimes the aorta subdivides soon
after its origin into two branches, which soon reunite. In one of these cases, the oesophagus
and trachea were found to pass through the interval left by their division ; this is the normal
condition of the vessel in the reptilia.
Surgical Anatomy. Of all the vessels of the arterial system, the aorta, and more especially
its arch, is most frequently the seat of disease ; hence it is important to consider some of the
consequences that nuiy ensue from aneurism of this part.
It will be remembered, that the ascending part of the arch is contained in the pericardium,
just behind the sternum, being crossed at its commencement by the pulmonary artery and riyht
auricular appendix, and having the root of the right lung behind, the vena cava on the right side,
and the pulmonary artery and left auricle on the left side.
Aneurism of the ascending aorta, in the situation of the aortic sinuses, in the great majority
of cases, affects the right coronary sinus ; this is mainly owing to the fact that the regurgitation
of blood upon the sinuses takes place chiefly on the right anterior aspect of the vessel. As the
aneurismal sac enlarges, it may compress any or all of the structures in immediate proximity with
it, but chiefly projects towards the right anterior side ; and, consequently, interferes mainly with
those structures that have a corresponding relation with the vessel. In the majority of cases, it
bursts into the cavity of the pericardium, the patient suddenly drops down dead, and, upon a post-
mortem examination, the pericardial sac is found full of blood : or it may compress the right
auricle, or the pulmonary artery, and adjoining part of the right ventricle, and open into one or
the other of these parts, or may press upon the superior cava.
Aneurism of the ascending aorta, originating above the sinuses, most frequently implicates the
right anterior wall of the vessel; this is probably mainly owing to the blood being impelled
against this part. The direction of the aneurism is also chiefly towards the right of the median
line. If it attains a large size and projects forwards, it may absorb the sternum and the carti-
lages of the ribs, usually on the right side, and appear as a pulsating tumor on the front of the
chest, just below the manubrium ; or it may burst into the pericardium, or may compress, or
open into the right lung, the trachea, bronchi, or oesophagus.
Regarding the transverse part of the arch, the student is reminded that the vessel lies on the
trachea, the oesophagus, and thoracic duct; that the recurrent laryngeal nerve winds around it;
and that from its upper part are given off three large trunks, which supply the head, neck, and
upper extremities. Now an aneurismal tumor taking origin from the posterior part or right
aspect of the vessel, its most usual site, may press upon the trachea, impede the breathing, or
produce cough, hcemoptysis, or stridulous breathing, or it may ultimately burst into that tulie.
producing fatal hemorrhage. Again, its pressure on the laryngeal nerves may give rise to symp-
toms which so accurately resemble those of laryngitis, that the operation of tracheotomy has in
some cases been resorted 1o, from the supposition that disease existed in the larynx; or it may
press upon the thoracic duct, and destroy life by inanition; or it may involve the oesophagus,
producing dysphagia; or may burst into the oesophagus, when fatal hemorrhage will occur.
Again, the innominate artery, or the left carotid, or subclavian, may be so obstructed by clots,
as to produce a weakness, or even a disappearance, of the pulse in one or the other wrist; or the
tumor may present itself at or above the manubrium, generally either in the median line, or to
the right of the sternum, and may simulate an aneurism of one of the arteries of the neck.
Aneurism affecting tlie descending part of the arch is usually directed backwards and to the
left side, causing absor[)tion of the vertebras and corresponding ribs ; or it may i)ress upon the
trachea, left bronchus, oesophagus, and the right and left lungs, generally tlie latter. When
rupture of the sac occurs, it usually takes ])lace into the left pleural cavity ; less freqiuMitly into
the \cA'i bronchus, the right pleura, or into the substance of the lungs or trachea. In this form
of aneurism, pain is almost a constant and characti-ristic symjjlom, referred to either the back or
chest, and usually radiating from the spine around the left side. This symptom depends upon
the aneurisnuil sac compressing the intercostal nerves against the bone.
Branches of the Arch of the Aorta. (Figs. 302, 303.^
The branches given off from the arch of the aorta are five in number : two of
small size from the ascending portion, the right and left coronary, and three of
largo size from the Iransversc; ))(iili(>ii, ihc iniiuiiiiualc artcr}^, the left common
carotid, and the left subclavian.
THE CORONARY. 4G9
Peculiarities. Position of the Branches. The branches, instead of arising from the highest
part of the arch (tlieir usual position), may be moved more to the right, arising from the com-
mencement of the transverse or upper part of the ascending portion; or the distance from one
another at their origin may be increased or diminished, the most frequent change in this respect
being the approximation of tlie left carotid towards the innominate artery.
The Number of the primary branches may be reduced to two : the left, carotid arising from the
innominate artery; or (more I'arely), the carotid and subclavian arteries of the left side arising
from a left innominate artery. But the number may be increased to four, from the right carotid
and subclavian arteries arising directly from the aorta, the innominate being absent. In most of
these latter cases, the right subclavian has been found to arise from the left end of the arch ; in
other cases, it was the second or third branch given off instead of the first. Lastly, the number
of trunks from the arch may be increased to five or six; in these instances, the external and
internal carotids arise separately from the arch, the common carotid being absent on one or both
sides.
Number usual, Arrangement different. When the aorta arches over to the right side, the
three branches have an arrangement the reverse of what is usual, the innominate supplying the
left side, and the carotid and subclavian (which arises separately) the right side. In other cases,
where the aorta takes its usual course, the two carotids may be joined in a common trunk, and
the subclavians arise separately from the arch, the right subclavian generally arising from the
left end of the arch.
Secondary Branches sometimes arise from the arch; most commonly such a secondary branch
is the left vertebral, which usually takes origin between the left carotid and left subclavian, or
beyond them. Sometimes, a thyroid branch is derived from the arch, or the right internal mam-
mary, or right vertebral, or, more rarely, both vertebrals.'
The Corojstaey Aeteries,
Tlie Coronary Arteries supply tlie lieart ; tliey are two in number, riglit and
left, arising near tlie commencement of tlie aorta immediately above the free
margin of tbe semilunar valves.
The Right Coronary Artery.^ about the size of a crow's quill, arises from the
aorta immediately above the free margin of the right semilunar valve, between
the pulmonary artery and the right appendix auriculte. It passes forwards to
the right side, in the groove between the right auricle and ventricle, and curving
around the right border of the heart, runs along its posterior surface as far as
the posterior interventricular groove, where it divides into two branches, one of
which continues onwards in the groove between the left auricle and ventricle,
and anastomoses with the left coronary; the other descends along the posterior
interventricular furrow, sup23l3dng branches to both ventricles and to the septum,
and anastomosing at the apex of the heart with the descending branch of the
left coronary.
This vessel sends a large branch along the thin margin of the right ventricle
to the apex, and numerous small branches to the right auricle and ventricle, and
the commencement of the pulmonary artery.
The Left Coronary .^ smaller than the former, arises immediately above the free
edge of the left semilunar valve, a little higher than the right ; it passes forwards
between the pulmonary artery and the left appendix auriculae, and descends
obliquely towards the anterior interventricular groove, where it divides into two
branches. Of these, one passes transversely outwards in the left auriculo-ventri-
cular groove, and winds around the left border of the heart to its posterior sur-
face, where it anastomoses with the superior branch of the right coronary ; the
other descends along the anterior interventricular groove to the apex of the
heart, where it anastomoses with the descending branch of the right coronary.
The left coronary supplies the left auricle and its appendix, both ventricles, and
numerous small branches to the pulmonary artery, and commencement of the
aorta.
Peculiarities. These vessels occasionally arise by a common trunk, or their number may be
increased to three ; the additional branch being of small size. More rarely, there are two addi-
tional branches.
' The anomalies of the aorta and its branches are minutely described by Ki-ause in Henle's
"Anatomy" (Brunswick, 1868), vol. iii. p. 203 et seq^.
470 ARTERIES.
Arteria Innominata.
The Innomiuate Artery is tlie largest brancli given off from tlie arch of the
aorta. It arises from the commencement of the transverse portion in front of
the left carotid, and, ascending obliquely to the upper border of the right sterno-
clavicular articulation, divides into the right common carotid and right subcla-
vian arteries. This vessel varies from an inch and a half to two inches in length.
Relations. Infront^ it is separated from the first bone of the sternum by the
Sterno-hyoid and Sterno-thyroid muscles, the remains of the thymus gland, and
the left innominate and right inferior thyroid veins which cross its root. Behind^
it lies upon the trachea, which it crosses obliquely. On the rigid side^ is the right
vena innominata, right pneumogastric nerve, and the pleura ; and on the left
side^ the remains of the thymus gland, and origin of the left carotid artery.
Plan of the Eelations of the Innominate Artery.
In Front.
Sternum.
Sternohyoid and Sterno.thyroid muscles.
Remains of thymus gland.
Left innominate and right inferior thyroid veins.
Inferior cervical cardiac branch from right pneumogastric nerve.
Right side. / \ L<^ft side.
Right vena innominata. / innominate \ Remains of thymus.
Right pneumogastric nerve. \ Artery, j Left Carotid.
Pleura.
Behind.
Trachea.
Peculiarities in point of division. When the bifurcation of the innominate artery varies
from the point above mentioned, it sometimes ascends a considerable distance above the sternal
end of the clavicle ; less frequently it divides below it. In the former class of cases, its length
may exceed two inches; and, in the lalter, be reduced to an inch or less. '1 hese are points of
considerable interest for the surgeon to remember in connection with the operation of tying this
vessel.
Branches. The arteria innominata occasionally supplies a thyroid branch (middle thyroid
artery), which ascends along the front of the trachea to the thyroid gland ; and sometimes a
thymic or bronchial branch. The left carotid is frequently joined with the innominate artery at
its origin. Sometimes, there is no innominate artery, the right subclavian arising directly Irom
the arch of the aorta.
Position. When the aorta arches over to the right side, the innominate is directed to the left
side of the neck instead of the right.
Collateral Circulation. Allan Burns demonstrated, on the dead subject, the possibility of the
establishment of the collateral circulation after ligature of the innominate artery, by tying and
dividing that artery, after which, he says : "Even coarse injection impelled into the aorta, passed
freely by the anastomosing l)ranches into the arteries of the right arm, filling tliem and all the
vessels of the head completely." {Surcjical Anatomy of the Head and Neck, p. 02.) The
branches by which this circulation would be carried on are very numerous; thus, all the commu-
nications across the middle line between the branches of the carotid arteries of ojiposite sides
would be available for the supply of blood to the right side of the head and neck ; while the
anastomosis between the superior intercostal of the subclavian and the first iKH'tic intercostal (see
infra on the collateral circulation after obliteration of the thoracic aorta), would bring the blood,
by a free and direct course, into the ritrht subclavian : the numerous connections, also, between
the lower intercostal arteries and the branches of the axillary and internal mammary arteries
would, doubtless, assist in the supply of blood to the right arm. while the ejjigastric. from the
external iliac, would, by means of its anastomosis with the internal mammary, compensate lor any
deficiency in the vascularity of the wall of the chest.
Surcjical Anatomy. Although the operation of tyini,'- the iniKnninate artery has been per-
formed by several suVgeons, for aneurism of the right "subclavian extending inwards as lar as the
Scalenus, in only one instance has it been attended with success.' Mott's patient, however, on
' The operation was performed by Dr. Smyth of New Orleans. See the New Sydenham
Society's " Jiieniiial Retrospect," for ISGo-C, p. 346.
COMMON CAROTID. ' 471
whom the operation was first performed, lived nearly four weeks, and Graefe's, more than two
months. The main obstacles to the operation are, as the student will perceive from his dissection
of this vessel, the deep situation of the artery behind and beneath the sternum, and the number
of important structures which surround it in every part.
In order to apply a ligature to this vessel, the patient is to be placed upon his back, with the
shoulders raised, and the head bent a little backwards, so as to draw out the artery from behind
the sternum into the neck. An incision two inches long is then made along the anterior border
of the Sterno-mastoid muscle, terminating at the sternal end of the clavicle. From this point, a
second incision is carried about the same length along the upper border of the clavicle. The
skin is then dissected back, and the Platysnm divided on a director: the sternal end of the Sterno-
mastoid is now brought into view, and a director being passed beneath it, and close to its under
surface, so as to avoid any small vessels, the muscle is to be divided transversely throughout the
greater part of its attacliment. By pressing aside any loose cellular tissue or vessels that may
now appear, the Sterno-hyoid and tSterno-thyroid muscles will be exposed, and must be divided,
a director being previously passed beneath them. The inferior thyroid veins may come into view,
and must be carefully drawn either upwards or downwards, by means of a blunt hook. On no
account should these vessels be divided, as it would add much to the difficulty of the operation,
and endanger its ultimate success. After tearing through a strong fibro-cellular lamina, the right
carotid is brought into view, and being traced downwards, the arteria vena innominata is arrived
at. The left vena innominata should now be depressed, the right vena innominata, the internal
jugular vein, and pneumogastric nerve drawn to the right side ; and a curved aneurism needle
may then be passed around the vessel, close to its surface, and in a direction from below upwards
and inwards; care being taken to avoid the right pleural sac, the trachea, and cardiac nerves.
The ligature should be applied to the artery as high as possible, in order to allovv room between
it and the aorta for the formation of a coagulum. 'i'he importance of avoiding the thyroid plexus
of veins during the primary steps of the operation, and the pleural sac whilst including the vessel
in the ligature, should be most carefully borne in mind, since secondary hemorrhage or pleurisy
has been the cause of death in all the fatal cases hitherto recorded.
Common Cakotid Arteries.
The Common Carotid Arteries, altliough occupjing a nearly similar position
in the neck, differ in position, and, consequently, in their relations at their
origin. The right carotid arises from the arteria innominata, behind the right
sterno-clavicular articulation; the left from the highest part of the arch of the
aorta. The left carotid is, consequently, longer and placed more deeply in the
thorax. It will, therefore, be more convenient to describe first the course and
relations of that portion of the left carotid which intervenes between the arch
of the aorta and the left sterno-clavicular articulation (see Fig. 302).
The left carotid within the thorax ascends obliquely outwards from the arch
of the aorta to the root of the neck. In front it is separated from the first piece
of the sternum by the Sterno-hyoid and Sterno-thyroid muscles, the left innomi-
nate vein, and the remains of the thymus gland ; hehind^ it lies on the trachea,
oesophagus, and thoracic duct. Internally^ it is in relation with the arteria
innominata; externally^ with the left pneumogastric nerve, and left subclavian
artery.
Plan of the Eelations of the Left Common Carotid.
Thoracic Portion.
In Front.
Sternum.
Sterno-hyoid and Sterno-thyroid muscles.
Left innominate vein.
Remains of thymus gland.
InternaVy. /- <-w^ \ Externalhi.
, , . . . /Lieft Oommon\ ^
Arteria innominata. I Carotid. Left pneumogastric nerve.
" Left subclavian artery.
Behind.
Esophagus.
Trachea.
Thoracic duct.
472
ARTERIES.
In the neck, tlie two common carotids resemble each other so closely, that
one description will apply to both. Each vessel passes obliquely upwards, from
behind the sterno-clavicular articulation, to a level with the upper border of the
thyroid cartilage, where it divides into the external and internal carotid ; these
names being derived from the distribution of the arteries to the external parts
of the head and face, and to the internal parts of the cranium respectively.
The course of the common carotid is indicated by a line drawn from the sternal
end of the clavicle below, to a point midway between the angle of the jaw and
the mastoid process above.
Fig. 304. — Surgical Anatomy of the Arteries of the Neck. Right Side.
Fig. 305.
ri(*n of &'
J3 ranches
oflhf \
EXTERNAL CAROTID \
At lli(! lower pnrt of tlio nock the two common enrntid nrtories arc separated
from cacli otlicr by a very small iiilci'val, 'wliich (••miniiis llu^. Iraclioa; but at
the upper part, the thyroid boily, the larynx and ])harynx jirqjcct forwards
betAveen the two vessels, and give the appearance of their being placed further
COMMON CAROTID. 473
back in that situation. Tile common carotid artery is contained in a slieatli
derived from the deep cervical fascia, which also incloses the internal jugular
vein and pneumogastric nerve, the vein lying on the outer side of the artery,
and the nerve between the artery and vein, on a plane posterior to both. On
opening the sheath, these three structures are seen to be separated from one
another, each being inclosed in a separate fibrous investment.
Relations. At the lower part of the neck the common carotid artery is very
deeply seated, being covered by the superficial fascia, Platysma, and deep fascia,
the Sterno-mastoid, Sterno-hyoid, and Sterno-thyroid muscles, and by the Omo-
hyoid opposite the cricoid cartilage; but in the upper part of its course, near its
termination, it is more superficial, being covered merely by the integument, the
superficial fascia, Platysma, deep fascia, and inner margin of the Sterno-mastoid,
and is contained in a triangular space, bounded behind by the Sterno-mastoid,
above by the posterior belly of the Digastric, and below by the anterior belly
of the Omo-hyoid. This part of the artery is crossed obliquely from within
outwards by the sterno-mastoid artery ; it is crossed also by the facial, lingual,
and superior thyroid veins, which terminate in the internal jugular, and descend-
ing on its sheath in front, is seen the descendens noni nerve, this filament being
joined by one or two branches from the cervical nerves, which cross the vessel
from without inwards. Sometimes the descendens noni is contained within the
sheath. The middle thyroid vein crosses the artery about its middle, and the
anterior jugular vein below. Behind, the artery lies in front of the cervical
portion of the spine, resting first on the Longus colli muscle, then on the Eectus
capitis anticus major, from which it is separated by the sympathetic nerve.
The recurrent laryngeal nerve and inferior thyroid artery cross behind the vessel
at its lower part. Internally, it is in relation with the trachea and thyroid
gland, the inferior thyroid artery and recurrent laryngeal nerve being inter-
posed: higher up, with the larynx and pharynx. On its outer side are placed
the internal jugular vein and pneumogastric nerve.
At the lower part of the neck, the internal jugular vein on the right side
diverges from the artery, but on the left side it approaches it, and often crosses
its lower part. This is an important fact to bear in mind during the per-
formance of any operation on the lower part of the left common carotid artery.
Plan of the Eelatioxs of the Common Caeotid Aeteky.
In Front.
Integument and fascia. Omo-hyoid.
Platysma. Descendens noni nerve.
Sterno-mastoid. Sterno-mastoid artery.
Sterno-hyoid. Superior thyroid, lingual, and facial veins.
Sterno-thyroid. Anterior jugular vein.
©Internally.
Trachea.
Thyroid gland.
Recurrent laryngeal nerve.
Interior thyroid artery.
Larynx.
Pharynx.
Behind.
Longus colli. Sympathetic nerve.
Eectus capitis anticus major. Inferior thyroid artery.
Recurrent laryngeal nerve.
Peculiarities as to Origin. The right common carotid may arise above or below its usual
point, the upper border of the sterno-clavicular articulation. This variation occurs in one out
of about eight cases and a half, and the origin is more frequently above than below the usual
point; or the artery may arise as a separate branch from the arch of the aorta, or in conjunction
with the left carotid. The left common carotid varies more frequently in its origin than the
right. In the majority of abnormal cases it arises with the innominate artery, or if the innomi-
nate artery is absent, the two carotids arise usually by a single trunk. The left carotid has a
474 ARTERIES.
tendency towards the right side of the arch of the aorta, being occasionally the first branch given
off from the transverse portion. It rarely joins with the left subclavian, except in cases of trans-
position of the arch.
Peculiarities as to Point of Division. The most important peculiarities of this vessel, in a
surgical point of view, relate to its place of division in the neck. In the majority of abnormal
cases, this occurs higher than usual, the artery dividing into two branches opposite the hyoid
bone, or even higher ; more rarely, it occurs below its usual place opposite the middle of the
larynx, or the lower border of the cricoid cartilage ; and one case is related by Morgagni, where
the common carotid, only an inch and a half in length, divided at the root of the neck. Very
rarely, the common carotid ascends in the neck without any subdivision, the internal carotid
being wanting ; and in two cases, the common carotid has been found to be absent, the external
and internal carotids arising directly from the arch of the aorta. This peculiarity existed on
both sides in one subject, on one side in the other.
Occasional Branches. The common carotid usually gives off no branches ; but it occasionally
gives origin to the superior thyroid, or a laryngeal branch, the inferior thyroid, or, more rarely,
the vertebral artery.
SurgicalAnatomy. The operation of tying the common carotid artery may be necessary in a
wound of that vessel or its branches, in an aneurism, or in a case of pulsating tumor of the orbit
or skull. If the wound involves the trunk of the common carotid, it will be necessary to tie the
artery above and below the wounded part. But in, cases of aneurism, or where one of the branches
of the common carotid is wounded in an inaccessible situation, it may be judged necessary to tie
the trunk. In such cases, the whole of the artery is accessible, and any part may be tied, except
close to either end. When the case is such as to allow of a choice being made, the lower part of
the carotid should never be selected as the spot upon which to place a ligature, for not only is
the artery in this situation placed very deeply in the neck, but it is covered by three layers of
muscles, and on the left side the jugular vein, in the great majority of cases, passes obliquely in
front of it. Neither should the upper end be selected, for here the superior thyroid, lingual, and
facial veins would give rise to very considerable difficulty in the application of a ligature. The
point most favorable for the operation is opposite the lower part of the larynx, and here a liga-
ture may be applied on the vessel, either above or below the point where it is crossed by the
Omo-hyoid muscle. In the former situation the artery is most accessible, and it may be tied'
there in cases of wounds, or. aneurism of any of the large branches of the carotid ; whilst in cases
of aneurism of the upper part of the carotid, that part of the vessel may be selected which is
below the Omo-hyoid. It occasionally happens that the carotid artery bifurcates below its usual
position: if the artery be exposed at its point of bifurcation, both divisions of the vessel should
be tied near their origin, in preference to tying the trunk of the artery near its termination ; and
if in consequence of the entire absence of the common carotid, or from its early division, two
arteries, the external and internal carotids, are met with, the ligature should be placed on that
vessel which is found on compression to be connected with the disease.
In this operation, the direction of the vessel and the inner margin of the Sterno-mastoid are
the chief guides to its performance.
To tie the Common Carotid above the Omo-hyoid. The patient should be placed on his back
with the head thrown back : an incision is to be made, three inches long, in the direction of the
anterior border of the Sterno-mastoid, from a little below the angle of the jaw to a level with the
cricoid cartilage : after dividing the integument, superficial fascia, and Platysma, the deep fascia
must be cut through on a director, so as to avoid wounding numerous small veins that are
usually found beneath. The head may now be brought forwards so as to relax the parts some-
what, and the margins of the wound held asunder by copper spatute. The descendens noni nerve
is now exposed, and must be avoided, and the sheath of the vessel having been raised by forceps,
is to be opened over the artery to a small extent at its inner side. The internal jugular vein
may now present itself alternately distended and relaxed; this should be compressed both above
and below, and drawn outwards, in order to facilitate the operation. The aneurism needle is now
passed from the outside, care being taken to keep the needle in close contact with the artery, and
thus avoid the risk of injuring the jugular vein, or including the vagus nerve. Before the liga-
ture is tied, it should be ascertained that nothing but the artery is included in it.
To tie the Common Carotid, below the Omo-hyoid. The patient should be placed in the -
same position as above mentioned. An incision about three inches in length is to be made,
parallel with the inner edge of the Sterno-mastoid, commencing on a level with the cricoid carti-
lage. 'J'he inner border of the Sterno-mastoid having been exposed, the sterno-mastoid artery
and a large vein, the middle thyroid, will be seen, aiid must be carefully avoided ; the Sterno-
mastoid is to be drawn outwards, and the Steriio-hyoid and thyroid muscfes inwards. The deep
fascia must now be divided below the Omo-liyoid n'luscle, and "the sheath having been exposed,
must 1)0 opened, care being taken to avoid the descendens noni, which here runs on the inner or
traeheal side. 'I'he jugular vein and vagus nerve being then pressed 1o the outer side, the needle
rnust bo passed round the artery from without inwiirds, great care being taken to avoid the infe-
rior thyroid artery, the recurrent laryngeal, and sympathetic nerves wliich lie behind it.
Collaternl Cirndalion. After ligature of the eommon carotid, the collateral circulation can
be perfectly established, by the free communication which exists between the carotid arteries of
EXTERNAL CAROTID.
475
opposite sides, both -witliont and within the cranium — and by enlargement of the branches of the
subclavian artery on the side corresponding' to that on which the vessel has been tied, the chief
communication outside the skull taking place between the superior and inferior thyroid arteries,
and the profunda cervicis, and anterior princeps cervicis of the occipital ; the vertebral taking
the place of the internal carotid within the cranium.
Sir A. Cooper had an opportunity of dissecting, thirteen years after the operation, the case in
which he first successfully tied the common carotid (the second case in which he performed the
operation). Guy's Hospital Reports, i. 56. The injection, however, does not seem to have been
a successful one. It showed merely that the arteries at the base of the brain (circle of Willis)
were much enlarged on the side of the tied artery, and that the anastomosis between the branches
of the external carotid on the afTected side and those of the same artery on the sound side was
free, so that the external carotid was pervious throughout.
External Caeotid Artery.
Tlie External Carotid Artery (Fig. 30-i) arises opposite tlie upper border of
tlie thyroid cartilage, and taking a slightly cnrved course, ascends upwards and
forwards, and then inclines baclvwards, to the space between the neck of the
condyle of the lower jaw, and the external meatus, where it divides into the
temporal and internal maxillary arteries. It rapidly diminishes in size in its
course up the neck, owing to the number and large size of the branches given
off from it. In the child, it is somewhat smaller than the internal carotid • but
in the adult, the two vessels are of nearly equal size. At its commencement
this artery is more superficial, and placed nearer the middle line than the
internal carotid, and is contained in the triangular space bounded bv the Sterno-
mastoid behind, the Omo-hyoid below, and the posterior belly of the Digastric
and Stylo-hyoid above; it is covered by the skin, Platysma, deep fascia and
anterior margin of the Sterno- mastoid, crossed by the hypoglossal nerve and
by the lingual and facial veins ; it is afterwards crossed by the Digastric and
Stylo-hyoid muscles, and higher up passes deeply into the substance of the
parotid gland, where it lies beneath the facial nerve and the junction of the
temporal and internal maxillary veins.
Internally is the hyoid bone, the wall of the pharynx, and the ramus of the
jaw, from which it is separated by a portion of the parotid gland.
Behind it, near its origin, is the superior laryngeal nerve ; and higher up, it
is separated from the internal carotid by the Stylo-glossus and Stylo-pharvngeus
muscles, the glosso-pharyngeal nerve, and part of the parotid gland.
Plax of the Eelatioxs of the External Carotid.
In Front.
Integument, superficial fascia.
Platysma and deep fascia.
Hypoglossal nerve.
Lingual and facial veins.
Digastric and Stylo-hyoid muscles.
Parotid gland with facial nerve and
temporo-maxillary vein in its sub-
stance.
Behind.
Superior laryngeal nerve.
Stylo-glossus.
Stylo-pharyngeus.
Glosso-pharyngeal nerve.
Parotid glaud.
Liternally.
Hyoid bone.
Pharynx.
Parotid gland.
Eamus of jaw.
Surgical Anatomy. The application of a ligature to the external carotid may be required in
cases of wounds of this vessel, or of its branches when these cannot be tied, and in some cases of
pulsating tumor of the scalp or face ; the operation, however, is very rarely performed, ligature
of the common carotid being preferable, on account of the number of branches given off from the
external. To tie this vessel near its origin, below the point where it is crossed by the Digastric,
an incision about three inches in length should be made along the margin of the Sterno-mastoid,
from the angle of the jaw to the cricoid cartilage, as in the operation for tying the common
carotid. To tie the vessel above the Digastric, between it and the parotid dand, an incision
should be made, from the lobe of the ear to the great cornu of the os hyoides, dividing successively
476 ARTERIES.
the skin, Platysnia, and fascia. By separating the posterior belly of the Dijxastric and Stylo-
hyoid muscles which are seen at the lower part of the wound, from the parotid g-land, the vessel
will be exposed, and a ligature may be applied to it. The circulation is at once re-established
by the free communication between n)ost of the large branches of the artery (facial, lingual,
superior thyroid, occipital) and the corresponding arteries of the opposite side, and by the free
anastomosis of the facial with branches from the internal carotid, of the occipital with branches
of the subclavian, etc.
Branches. The external carotid artery gives off eight branches, which, for
convenience of description, may be divided into four sets. (See Fig, 305, Phm
of the Branches.)
Anterior, Posterior. Ascending. Terminal.
Superior Thyroid. OccipitaL Ascending Pha- Temporal.
Lingual. Posterior Auricular. ryngeal. Internal Maxillary.
Facial.
The student is here reminded that many variations are met with in the number,
origin, and course of these branches in different subjects; but the above arrange-
ment is that which is found in the great majority of cases.
■ The SuPEEiOR Thyroid Artery (Figs. 304: and 309) is the first branch given
off from the external carotid, being derived from that vessel just below the
great cornu of the hyoid bone. At its commencement, it is quite superficial,
being covered by the integument, fascia, and Platysnia, and is contained in the
triangular space bounded by the Sterno-mastoid, Digastric, and Omo-hyoid
muscles. After running upwards and inwards for a short distance, it curves
downwards and forwards, in an arched and tortuous manner, to the upper part
of the thyroid gland, passing beneath the Omo-hyoid, Sterno-hyoid, and Sterno-
thyroid muscles; and distributes numerous branches to the anterior surface of
the gland, anastomosing with its fellow of the opposite side, and with, the inferior
thyroid arteries. Besides the arteries distributed to the muscles and the sub-
stance of the gland, the branches of the superior thyroid are the following :
Hyoid. Superior Laryngeal.
Superficial descending branch (Sterno-mastoid). Crico-thyroid.
The hyoid is a small branch which runs along the lower border of the os
hyoides, beneath the thj^'ro-hyoid muscle ; after supplying the muscles connected
to that bone, it forms an arch, by anastomosing with the vessel of the opposite
side.
The superficial descending branch runs downwards and outwards across the
sheath of the common carotid artery, and supplies the Sterno-mastoid and
neighboring muscles and integument. It is of importance that the situation of
this vessel be remembered, in the operation for tying the common carotid
artery. There is often a distinct branch from the external carotid distributed
to the Sterno-mastoid muscle.
The superior laryngeal^ larger than either of the preceding, accompanies the
superior laryngeal nerve, beneath the Thyro-hyoid muscle ; it pierces the thyro-
hyoid membrane, and supplies the muscles, mucous membrane, and glands of
the ]arynx and epiglottis, anastomosing Avitli the branch from the opposite side.
Tlic cr/co-///?/ro?>i (inferior laryngeal) is a small branch wliich runs transversely
across the crico-thyroid membrane, communicating with the artery of the opposite
side. The position of tliis vessel should be remembered, as it may prove the
source of troublesome hemorrhage during the operation of laryngotomy.
t^nrriical Anatomy. The superior thyroid, or sonio of its branelios, is often divided in cases
of cut throat, giving rise to considerable henu)rrhage. In such cases, the artery should be secured,
the wound being enlarged for tliat purpose, if necessary. The operation may be easily performed,
the position of the artery being very superficial, and the only structures of importance covering
it being a few small veins. Tlie operation of lying the superior thyroid artery, in l)ronchocele,
has been porformed in numerous instances with partial or temporary success. When, however,
the collateral circulation lietweeu this vessel and the artery of the opposite side, and the inferior
thyroid, is completely rc-cstablishcd. the tumor usually regains its former size.
LINGUAL. 477
Tlie Lingual Aetery (Fig. 309) arises from tlie external carotid between the
superior tlijroid and facial; it runs obliquely upwards and inwards to the
great cornu of the hjoid bone, then passes horizontally forwards parallel with
the great cornu, and, ascending perpendicularly to the under surface of the
tongue, turns forwards on its under surface as far as the tip of that organ, under
the name of the ranine artery.
Relations. Its first, or oblique portion, is superficial, being contained in the
triangular space already described, resting upon the middle constrictor of the
pharynx, and covered by the Platysma, and fascia of the neck. Its second, or
horizontal portion, also lies upon the Middle constrictor, being covered at first
by the tendon of the Digastric and the Stylo-hyoid muscle, and afterwards by
the Hyo-glossus, the latter muscle separating it from the hypoglossal nerve. Its
third, or ascending portion, lies between the Hyo-glossus and Genio-hyo-giossus
muscles. The fourth, or terminal part, under the name of the ranine, runs along
the under surface of the tongue to its tip : it is very superficial, being covered
only by the mucous membrane, and rests on the Linguaiis on the outer side of
the Genio-hyo-glossus. The hypoglossal nerve lies nearly parallel with the
lingual artery, separated from it, in the second part of its course, by the Hyo-
glossus muscle.
The branches of the lingual artery are, the
Hyoid. Sublingual.
Dorsalis Linguse. Eaniue.
The hyoid hranch runs along the U23per border of the hyoid bone, supplying
the muscles attached to it and anastomosing with its fellow of the opposite side.
The dorsalis Unguse (Fig. 309) arises from the lingual artery beneath the Hyo-
glossus muscle (which, in the figure, has been partly cut away, to show the
vessel); ascending to the dorsum of the tongue, it supplies the mucous mem-
brane, the tonsil, soft palate, and epiglottis ; anastomosing with its fellow from
the opposite side.
The sublingual^ which may be described as a branch of bifurcation of the
lingual artery, arises at the anterior margin of the Hyo-glossus muscle, and,
running forwards and outwards beneath^ the Mylo-hyoid to the sublingual gland,
supplies its substance, giving branches to the Mylo-hyoid and neighboring
muscles, the mucous membrane of the mouth and gums.
The ranine may be regarded as the other branch of bifurcation, or, as is more
usual, as the continuation of the lingual artery ; it runs along the under surface
of the tongue, resting on the Linguaiis, and covered by the mucous membrane
of the mouth ; it lies on the outer side of the Genio-hyo-glossus, and is covered
by the Hyo-glossus and Stylo-glossus, accompanied by the gustatory nerve. On
arriving at the tip of the tongue, it anastomoses with the artery of the opposite
side. These vessels in the mouth are placed one on each side of the frsenum.
Surgical Anatomy. The lingual artery may be divided near its origin in cases of cut throat,
a complication that not unfrequently happens in this class of wounds, or severe hemorrhage which
cannot be restrained by ordinary means, may ensue from a woimd. or deep ulcer, of the tongue.
In the former case, the primary wound may be enlarged if necessary, and the bleeding vessel
secured. In the latter case, it has been suggested that the lingual artery should be tied near its
origin. Ligature of the lingual artery is also occasionally practised, as a palliative measure, in
cases of tumor of the tongue, in order to check the progress of the disease. The operation is a
difficult one, on account of the depth of the artery, the number of important parts by which it is
surrounded, the loose and yielding nature of the parts upon which it is supported, and its occa-
sional irregularity of origin. An incision is to be made, about two and a half inches in length,
running obliquely downwards and backwards, and having its centre opposite the point of the great
cornu of the hyoid bone, which is the guide to the artery. The parts being gradually dissected,
the hypoglossal nerve will come first into view, and then the artery must be carefully sought for
among the loose tissue at the bottom of the wound, care being taken not to open the pharynx.
Large veins, the internal jugular or some of its branches, may be met with, and prove a source of
embarrassment.
' That is to say. it is deeper than the muscle in dissecting from the surface. In the natural
position of the body, the artery lies above the muscle.
478
ARTERIES.
Troublesome hemorrhage may occur in the division of the frisenum in children, if the ranine
artery, which lies on each side of it, is cut through. Tlie student should remember that the ope-
ration is always to be performed with a pair of blunt-pointed scissors, and the mucous membrane
only is to be divided by a very superficial cut, which cannot endanger any vessel. The scissors,
also, should be directed away from the tongue. Any further liberation of the tongue, which may
be necessary, can be effected by tearing.
The Facial Artery (Fig. 306) arises a little above the lingual, and ascends
obliquely forwards and upwards, beneath the body of the lower jaw, to the sub-
, maxillary gland, in which it lies imbedded in a groove on its posterior and upper
Fig. 306.— The Arteries of the Face and Scalp.'
border ; this may be called the cervical part of the artery. It then curves up-
wards over the body of the jaw at the anterior inferior angle of the Masseter
muscle, ascends forwards and upwards across the check to the angle of the
mouth, passes up along the side of the nose, and terminates at the inner canthus
of the eye, under the name of the angular artery. This vessel, both in the
neck, and on the face, is remarkably tortuous ; in tlie former situation, to accom-
modate itself to the movement of the pharynx in deglutition ; and in the latter,
to the movements of the jaw, and the lips and cheeks.
Relations. In thf. nech^ its origin is su]ierlicial, being covered by the intega-
ment, Platysma, and fascia; it then passes beneath the Digastric and Stylo-hyoid
muscles, and \\u\ sii1)iiiaxillary gland. On theface^ wlicre it passes over the body
' The muscular tlHsuo of the lips must be supposed to have been cut away, in order to show the
course of the coronary arteries.
FACIAL. 479
of the lower jaw, it is comparatively superficial, lying immediately beneatli the
Platysma. In this situation, its pulsation may be distinctly felt and compression
of the vessel effectually made against the bone. In its course over the face, it
is covered by the integument, the fat of the cheek, and, near the angle of the
mouth, by the Platysma and Zygomatic muscles. It rests on the Buccinator,
the Levator anguli oris, and the Levator labii superioris. It is accompanied by
the facial vein throughout its entire course; the vein is not tortuous like the
artery, and, on the face, is separated from that vessel by a considerable interval,
lying to its outer side. The branches of the facial nerve cross the artery, and
the infra- orbital nerve lies beneath it.
The branches of this vessel may be divided into two sets, those given off below
the jaw (cervical), and those on the face (facial) : —
Cervical Branches. Facial Branches.
Inferior or Ascending Palatine. Muscular.
Tonsillar. Inferior Labial,
Submaxillary. Inferior Cor6nary,
Submental. Superior Coronary.
Lateralis Nasi.
Angular.
The inferior or ascending palatine (Fig. 309) passes up between the Stylo-
glossus and Stylo-phar3mgeus to the outer side of the pharynx. After supplying
these muscles, the tonsil, and Eustachian tube, it divides, near the Levator
palati, into two branches ; one follows the course of the Tensor palati, and sup-
plies the soft palate and the palatine glands ; the other passes to the tonsil,
which it supplies, anastomosing with the tonsillar artery. These vessels inos-
culate with the posterior palatine branch of the internal maxillary artery.
The tonsillar branch (Fig. 309) passes up along the side of the pharynx, and,
perforating the Superior constrictor, ramifies in the substance of the tonsil and
root of the tongue.
The suhnaxillary consist of three or four large branches, which supply the
submaxillary gland, some being prolonged to the neighboring muscles, lymphatic
glands, and integument.
The submental, the largest of the cervical branches, is given off from the facial
artery, just as that vessel quits the submaxillary gland ; it runs forwards upon
the Mylo-hyoid muscle, just below the body of the jaw, and beneath the Digas-
tric; after supplying the muscles attached to the jaw, and anastomosing with
the sub-lingual artery, it arrives at the symphysis of the chin, where it divides
into a superficial and deep branch ; the former turns round the chin, and, pass-
ing between the integument and Depressor labii inferioris, sui^plies both, and
anastomoses with the inferior labial. The deep branch passes beneath the latter
muscle and the bone, supplies the lip, and anostomoses with the inferior labial
and mental arteries.
The muscular branches are distributed to the internal Pterygoid, Masseter,
and Buccinator.
The inferior labial passes beneath the Depressor anguli oris, to supply the
muscles and integument of the lower lip, anastomosing with the inferior coronary,
and submental branches of the facial, and with the mental branch of the inferior
dental artery.
The inferior coronary is derived from the facial artery, near the angle of the
mouth ; it passes upwards and inwards beneath the Depressor anguli oris, and,
penetrating the Orbicularis muscle, runs in a tortuous course along the edge of
the lower lip between this muscle and the mucous membrane, inosculating with
the artery of the opposite side. This artery supplies the labial glands, the
mucous membrane, and muscles of the lower lip ; and anastomoses with the
inferior labial, and mental branch of the inferior dental artery.
480 ARTERIES.
The sui-)erior coronary is larger, and more tortuous in its course tlian tlie pre-
ceding. It follows tlie same course along the edge of the upper lip, lying
between the mucous membrane and the Orbicularis, and anastomoses with the
artery of the opposite side. It supplies the textures of the upper lip, and gives
oft" in its course two or three vessels which ascend to the nose. One, named the
artery of the septum, ramifies on the septum of the nares as far as the point of
the nose ; another supplies the ala of the nose.
The lateralis nasi is derived from the facial, as that vessel is ascending along
the side of the nose ; it supplies the ala and dorsum of the nose, anastomosing
with its fellow, the nasal branch of the ophthalmic, the artery of the septum, and
the infra-orbital.
The angular artery is the termination of the trunk of the facial ; it ascends to
the inner angle of the orbit, accompanied by a large vein, the angular ; it dis-
tributes some branches on the cheek which anastomose with the infra- orbital,
and, after supplying the lachrymal sac, and Orbicularis muscle, terminates by
anastomosing with the nasal branch of the ophthalmic artery.
The anastomoses of the facial artery are very numerous, not only with the
vessel of the opposite side, but with other vessels from different sources, viz.,
with the sublingual branch of the lingual, with the mental branch of the inferior
dental as it emerges from the mental foramen, with the ascending pharyngeal
and posterior palatine, and with the ophthalmic, a branch of the internal carotid;
it also inosculates with the transverse facial, and with the infra-orbital.
Peculiarities. The facial artery not unfrequently arises by a common trunk M'ith the lingual.
This vessel also is subject to some variations in its size, and in the extent to which it supplies
the face. It occasionally terminates as the' submental, a'.id not unfrequently supplies the face
only as hiarh as the angle of the mouth or nose. The deficiency is then supplied by enlargement,
of one of the neighboring arteries.
Surgical Anatomy. The passage of the facial artery over the body of the jaw would appear
to afford a favorable position for the application of pressure in cases of hemorrhage from the lips,
the result either of an accidental wound, or from an operalion ; but its application is useless,
except for a very short time, on account of the free communication of this vessel with its fellow,
and with numerous branches from different sources. In a wound involving the lip, it is better to
seize the part between the fingers, and evert it, when the bleeding vessel may be at once secured
with a tenaculum. In order to prevent hemorrhage in cases of excision, or in the removal of
diseased growths from the part, the lip should be compressed on each side between the finger
and thumb, v/hilst the surgeon excises the diseased part. In order to stop hemorrhage where the
lip has been divided in an operation, it is necessary, in uniting the edges of the wound, to pass
the sutures through the cut edges, almost as deep as its mucous surl'ace ; by these means, not
only are the cut surfaces more neatly and securely adapted to each other, but the possibility of
hemorrhage is prevented by including in the suture the divided artery. If the suture is, on
the contrary, passed through merely the cutaneous portion of the wound, hemorrhage occurs into
the cavity of the mouth. 'J'he student should, lastly, observe the relation of the angular artery
to the lachrymal sac, and it will be seen that, as the vessel passes up along the inner margin of
the orbit, it ascends on its nasal side. In operating for fistula lachrymalis, the sac should always
be opened on its outer side, in order that this vessel may be avoided.
The Occipital Aktery (Fig. 306) arises from the posterior part of the exter-
nal carotid, opposite the facial, near the lower margin of the Digastric nuiscle.
At its origin, it is covered by the posterior belly of the Digastric and Stylo-
hyoid muscles, and part of the parotid gland, the liypoglossal nerve winding
around it from behind forwards ; higher up, it passes across the internal carotid
artery, the internal jugular vein, and the pncumogastric and spinal accessory
nerves; it then ascends to tljc interval between the transverse process of the
atlas, and the mastoid process of the temporal bone, and passes horizontally
backwards, grooving the surface of the latter bone, being covered by the Sterno-
rnastoid, Splcnius, Digastric, and Trachelo-mastoid nuiscli's, iiiid resting upon
the Com plexus, Superior oblique, and Eectus capitis posticus major muscles:
it then ascends vertically npwnrds, piercing tlie cranial attachment of the Tra-
pezius, find ])asses in ;i Ini-inoiis course over tlic <.)cciput, as high as ihc vertex,
where it divides into nuiMcr(,)US branches.
POSTERIOR AURICULAR. 481
The brandies given off from tliis vessel are,
Muscular. Mening-eal.
Auricular. Arteria Princeps Cervicis.
The muscular branches supply the Digastric, Stylo-hvoid, Sterno-mastoid,
Splenius, and Trachelo- mastoid muscles. The branch distributed to the Sterno-
mastoid is of large size.
The auricular branch supplies the back part of the concha.
The meningeal branch ascends with the internal jugular vein, and enters the
skull through the foramen lacerum posterius, to supply the dura mater in the
posterior fossa.
The arteria 2yrinceps cervicis (Fig. 309) is a large branch which descends along
the back part of the neck, and divides into a superficial and deep branch. The
former runs beneath the Splenius, giving off branches which perforate that
muscle to supply the Trapezius, anastomosing with the superficial cervical artery :
the latter passes beneath the Gomplexus, between it and the Semispinalis colli,
and anastomoses with the vertebral and deep cervical branch of the superior
intercostal. The anastomosis between these vessels serves mainly to establish
the collateral circulation after ligature of the carotid or subclavian artery.
The cranial branches of the occipital artery are distributed upon the occiput ;
they are very tort nous, and lie between the integument and Occipito-frontalis,
anastomosing with the artery of the opposite side, the posterior auricular, and
temporal arteries. They supply the back part of the Occipito-frontalis muscle,
the integument and pericranium, and one or two branches occasionally pass
through the parietal or mastoid foramina, to supply the dura mater.
The Posterior Auricular Artery (Fig. 306) is a small vessel which arises
from the external carotid, above the Digastric and Stylo-hyoid muscles, opposite
the apex of the styloid process. It ascends, under cover of the parotid gland, to
the groove between the cartilage of the ear and the mastoid process, immediately
above which it divides into two branches, an anterior, passing forwards to anas-
tomose with the posterior division of the temporal ; and a posterior, communi-
cating with the occipital. Just before arriving at the mastoid process, this artery
is crossed by the portio dura, and has beneath it the spinal accessory nerve.
Besides several small branches to the Digastric, Stylo-hyoid, and Sterno-mas-
toid muscles, and to the parotid gland, this vessel gives off' two branches : —
Stylo-mastoid. Auricular.
The stylo-mastoid branch enters the stylo-mastoid foramen, and supplies the
tympanum, mastoid cells, and semicircular canals. In the young subject a
branch from this vessel forms, with the tympanic branch from the internal maxil-
lary, a vascular circle, which surrounds the auditory meatus, and from which
delicate vessels ramify on the membrana tympani.
The auricular branch is distributed to the back part of the cartilage of the ear,
upon which it ramifies minutely, some branches curving round the margin of
the fibro- cartilage, others perforating it, to supply its anterior surface.
The AscEN"DmG Pharyngeal Artery (Fig. 309), the smallest branch of the
external carotid, is a long slender vessel, deeply seated in the neck, beneath the
other branches of the external carotid and the Stylo -phai:yngeus muscle. It
arises from the back part of the external carotid, near the commencement of that
vessel, and ascends vertically between the internal carotid and the side of the
pharynx, to the under surface of the base of the skull, lying on the Eectus capi-
tis anticus major. Its branches maybe subdivided into three sets: 1. Those
directed outwards to supply muscles and nerves. 2. Those directed inwards to
the pharynx. 3. Meningeal branches.
The external branches are numerous small vessels, which supply the Recti capi-
tis antici muscles, the sympathetic, hypoglossal, and pneumogastric nerves, and
31
482 ARTERIES.
'the ..lympliatic glands of the neck, anastomosing witli the ascending cervical
artery.
The pharyngeal branches are three or fonr in number. Two of these descend
to supply the middle and inferior Constrictors and the Stylo-pharyngeus, rami-
fying in their substance and in the mucous membrane lining them. The largest
of the pharyngeal branches passes inwards, running upon the Superior constrictor,
and sends ramifications to the soft palate. Eustachian tube, and tonsil, which take
the place of the ascending palatine branch of the facial artery, when that vessel
is of small size.
The meningeal branches consist of several small vessels, which pass through
foramina in the base of the skull, to supply the dura mater. One, the posterior
meningeal, enters the cranium through the foramen lacerum posterius, with the
internal jugular vein. A second passes through the foramen lacerum medium ;
and occasionally a third through the anterior condyloid foramen. They are all
distributed to the dura mater.
The Temporal Artery (Fig. 306), the smaller of the two terminal branches
of the external carotid, appears, from its direction, to be the continuation of that
vessel. It commences in the substance of the parotid gland, in the interspace
between the neck of the condyle of the lower jaw and the external meatus, crosses
over the root of the zygoma, immediately beneath the integument, and divides
about two inches above the zygomatic arch into two branches, an anterior and
a posterior.
The anterior temporal inclines forwards over the forehead, supplying the mus-
cles, integument, and pericranium in this region, and anastomoses with the supra-
orbital and frontal arteries, its branches being directed from before backwards.
The posterior temporal^ larger than the anterior, curves upwards and back- '
wards along the side of the head, lying above the temporal fascia, and inoscu-
lates with its fellow of the opposite side, and with the posterior auricular and
occipital arteries.
The temporal artery, as it crosses the zygoma, is covered by the Atrahens
aurem muscle, and by a dense fascia given oft' from the parotid gland ; it is also
usually crossed by one or two veins, and accompanied by branches of the facial
and auriculo-temporal nerves. Besides some twigs to the parotid gland, the
articulation of the jaw, and the Masseter muscle, its branches are the
Transverse Facial. Middle Temporal.
Anterior Auricular,
The transverse facial is given off from the temporal before that vessel quits
the parotid gland ; running forwards through its substance, it passes transversely
across the face, between Steno's duct and the lower border of the zygoma, and
divides on the side of the face into numerous branches, which supply the parotid
gland, the Masseter muscle, and the integument, anastomosing with the facial
and infraorbital arteries. This vessel rests on the Masseter, and is accompanied
by one or two branches of the facial nerve. It is sometimes a branch of the
external carotid,
Tlie middle temporal artery arises immediately above the zj^gomatic arch, and
perforating the temporal fascia, supplies the Temporal muscle, anastomosing with
the deep temporal branches of the internal maxilhiry. It occasionally gives off
an orbital branch, which runs along the upper border of tlie zygoma, between
the two layers of the temporal fascia, to the outer angle of the orbit. This
branch supplies the Orbicularis palpebrarum, and anastomoses with the lach-
rymal and palpebral branches of the ojilithalmic artciy.
The anterior a'^iricvJar hrannhes arc distributed to the anterior portion of the
pinna, the lobnlo, and part of the external meatus, anastom(jsing with branches
of the posterior auricular.
Snrriical Avntnmy. Tt, nccapinnally liappons tliut Ihn snrcronn is callod upon to porform Mie
operation of artcriotomy \\\n)\\ tliis vcssol in cases of iiiflaniniation of the eye or brain. Under
INTERNAL MAXILLARY.
483
these circumstances, the anterior branch is the one usually selected. If the student will consider'
the relations of the trunk of this vessel, as it crosses the zygomatic arch, with the surrounding'
structures, he will observe that it is covered by a thick and dense fascia, crossed by one or two
veins, and accompanied by branches of the facial and auriculo-teniporal nerves. Bleeding should
not be performed in this situation, as much difficulty may arise from the dense fascia over the
vessel preventing a free flow of blood, and considerable pressure is requisite afterwards to repress
the hemorrhage. Again, a varicose aneurism may be formed by the accidental opening of one of
the veins in front of the artery ; or severe neuralgic pain may arise from the operation implicating
one of the nervous filaments in the neighborhood.
The anterior branch is, on the contrary, subcutaneous, is a large vessel, and as readily com-
pressed as any other portion of the artery ; it should consequently always be selected for the
operation.
The Inteenal Maxillary (Fig. 307), tlie larger of tlie two terminal branches
of the external carotid, passes inwards, at right angles from that vessel, to the
Fig. 307. — The Internal Maxillary Artery, and its Branches.
Fig. 308. Fla^ of ihe Branches
Deefi Tfmlliir«,l\,
iulacllc Meningeal ____^^
Mrvt'tiffta Parvti — rCi_
Tumfianic c;:^ t/|
2'^rctr Bintal-
jFf/ryyc •Falati-n t
J Vidian
> ^ [Descending Fdlaftni
~ ' FdlaUiia
inner side of the neck of the condyle of the lower jaw, to supply the deep strnc-
tures of the face. At its origin, it is imbedded in the substance of the parotid
gland, being on a level with the lower extremity of the lobe of the ear.
In the first part of its course (maxillary portion), the artery passes horizontally
forwards and inwards, between the ramus of the jaw and the internal lateral
ligament. The artery here lies parallel with the auriculo-temporal nerve ; it
crosses the inferior dental nerve, and lies beneath the narrow portion of the
External pterygoid muscle.
In the second part of its course (pterygoid portion), it runs obliquely for-
484 ARTERIES.
wards and upwards upon tlie outer surface of tlie External pterygoid muscle,
being covered by the ramus of the lower jaw, and lower part of the Temporal
muscle.
In the third part of its course (spheno-maxillary portion), it approaches the
superior maxillary bone, and enters the spheno-maxillary fossa, in the interval
between the processes of origin of the External pterygoid, where it lies in rela-
tion with Meckel's ganglion, and gives off its terminal branches.
Peculiarities. Occasionally, this artery passes between the two Pterygoid muscles. The vessel
in this case passes forwards to the interval between the processes of origin of the External ptery-
goid, in order to reach the superior maxillary bone. Sometimes the vessel escapes from beneath
the External pterygoid by perforating the middle of that muscle.
The branches of this vessel may be divided into three groups, corresponding
with its three divisions.
Branches from the Maxillary Portion (Fig. 308),
Tympanic (anterior). Small Meningeal.
Middle Meningeal. Inferior Dental.
The tympanic hranch passes upwards behind the articulation of the lower jaw,
enters the tympanum through the fissure of Glaser, Supplies the Laxator tym-
pani, and ramifies upon the membrana tympani, anastomosing with the stylo-
mastoid, Yidian, and tympanic branch from the internal carotid.
The middle meningeal is the largest of the branches which supply the dura
mater. It arises from the internal maxillary between the internal lateral liga-
ment and the neck of the jaw, and passes vertically upwards to the foramen
spinosum of the sphenoid bone. On entering the cranium, it divides into two-
branches, anterior and posterior. The anterior branch, the larger, crosses the
great ala of the sphenoid, and reaches the groove, or canal, in the anterior infe-
rior angle of the parietal bone : it then divides into branches, which spread out
between the dura mater and internal surface of the cranium, some passing up-
wards over the parietal bone as far as the vertex, and others backwards to the
occipital bone. The posterior branch crosses the squamous portion of the tem-
poral, and on the inner surface of the parietal bone divides into branches which
supply the posterior part of the dura mater and cranium. The branches of this
vessel are distributed partly to the dura mater, but chiefly to the bones ; they
anastomose with the arteries of the opposite side, and with the anterior and
posterior meningeal.
The middle meningeal, on entering the cranium, gives off the following colla-
teral branches: 1. Numerous small vessels to the ganglion of the fifth nerve,
and to the dura mater in this situation. 2. A branch to the facial nerve, which
enters the hiatus Fallopii, supplies the facial nerve, and anastomoses with the
stylo-mastoid branch of the posterior auricular artery. 8. Orbital branches,
which pass through the sphenoidal fissure, or through separate canals in the
great wing of the sphenoid to anastomose with the lachrji^mal or other branches
of the ophthalmic artery. 4. Temporal branches, which pass through foramina
in the great wing of the sphenoid, and anastomose in the temporal fossa witli
the deep temporal arteries.
The sm^all meningeal is sometimes derived from the preceding. It enters the
skull through the foramen ovale, and supplies the Casseriaii ganglion and dura
mater. Before entering the cranium, it gives ofl'a brancli to the nasal fossa and
soft palate.
l^he inferior denfxd descends Avitli tlic dental norvo, to the foramen on the inner
side of the ramus of the jaw. It runs along the dental canal in the substance
of the bone, accompanied by the nerve, and opposite the first bicuspid tooth
divides into two branches, incisor and mental ; the former is continued forwards
beneath the incisor teeth as far as the symphysis, where it anastomoses with the
artery of the opposite side ; the mental branch escapes with the nerve at the
INTERNAL MAXILLARY. 485
mental foramen, supplies the structures composing tlie chin, and anastomoses
with the submental, inferior labial, and inferior coronary arteries. As the
dental artery enters the foramen, it gives oft' a mylo-hyoid branch, which runs
in the Mylo-hyoid groove, and ramifies on the under surface of the Mylo-hyoid
muscle. The dental and incisor arteries during their course through the sub-
stance of the bone give oft' a few twigs which are lost in the cancellous tissue,
and a series of branches which correspond in number to the roots of the teeth :
these enter the minute apertures at the extremities of the fangs, and supply the
pulp of the teeth.
Branches of the Second, or Pterygoid Portion.
Deep Temporal. Masseteric.
Pterygoid. Buccal.
These branches are distributed, as their names imply, to the muscles in the
maxillary region.
The deep temporal branches^ two in number, anterior and posterior, each occupy
that part of the temporal fossa indicated by its name. Ascending between the
temporal muscle and pericranium, they supply that muscle, and anastomose
with the other temporal arteries; the anterior branch communicating with the
lachrymal through small branches which perforate the malar bone, and great
wing of the sphenoid.
The pterygoid hranclies^ irregular in their number and origin, supply the
Pterygoid muscles.
The masseteric is a small branch which passes outwards above the sigmoid
notch of the lower jaw, to the deep surface of the Masseter. It supplies that
muscle, and anastomoses with the masseteric branches of the facial and with the
transverse facial artery.
The buccal is a small branch which runs obliquely forwards between the
Internal pterygoid and the ramus of the jaw, to the outer surface of the Bucci-
nator, to which it is distributed, anastomosing with branches of the facial artery.
Branches of the Third, or Spheno-maxillary Portion.
Alveolar. Vidian.
Infraorbital. Ptery go-palatine.
Posterior or Descending Palatine. Nasal or Spheno-palatine.
The alveolar is given off from the internal maxillary by a common branch
with the infraorbital, and just as the trunk of the vesssel is passing into the
spheno-maxillary fossa. Descending upon the tuberosity of the superior maxil-
lary bone, it divides into numerous branches; one, the superior dental, larger
than the rest, supplies the molar and bicuspid teeth, its branches entering the
foramina in the alveolar process; some branches pierce the bone to supply the
lining of the antrum, and others are continued forwards on the alveolar process
to supply the gums.
The infraorbital appears, from its direction, to be the continuation of the
trunk of the internal maxillary. It arises from that vessel by a common trunk
with the preceding branch, and runs along the infraorbital canal with the
superior maxillary nerve, emerging upon the face at the infraorbital foramen,
beneath the Levator labii superioris. Whilst contained in the canal, it gives
oft' branches which ascend into the orbit, and supply the Inferior rectus and
Inferior oblique muscles, and the lachrymal gland. Other branches descend
through canals in the bone, to supply the mucous membrane of the antrum,
and the front teeth of the upper jaw. On the face, it supplies the lachrymal
sac, and inner angle of the orbit, anastomosing with the facial artery and nasal
486 ARTERIES.
brancTi of tlie ophtlialniic ; and other branches descend beneath the Levator
labii superioris, and anastomose with the transverse facial and buccal branches.
The four remaining branches arise from that portion of the internal' maxillary
which is contained in the spheno-maxillary fossa.
The descending •palatine passes down along the posterior palatine canal with
the posterior palatine branches of Meckel's ganglion, and emerging from the
posterior palatine foramen, runs forwards in a groove on the inner side of the
alveolar border of the hard palate to be distributed to the gums, the mucous
membrane of the hard palate, and palatine glands. "Whilst it is contained in
the palatine canal, it gives off branches, which descend in the accessory palatine
canals to su.pply the soft palate, anastomosing with the ascending palatine artery ;
and anteriorly it terminates in a small vessel, which ascends in the anterior
palatine canal, and anastomoses with the artery of the septum, a branch of the
spheno-palatine.
The Vidian branch passes backwards along the Vidian canal with the Vidian
nerve. It is distributed to the upper part of the pharynx and Eustachian tube,
sending a small branch into the tympanum.
The ptery go -palatine is also a very small branch, which passes backwards
through the pterygo-palatine canal with the pharyngeal nerve, and is distri-
buted to the upper part of the pharynx and Eustachian tube.
The nasal or spheno-palatine passes through the spheno-palatine foramen into
the cavity of the nose, at the back part of the superior meatus, and divides into
two branches ; one internal, the artery of the septum, passes obliquely downwards
and forwards along the septum nasi, supplies the mucous membrane, and anasto-
moses in front with the ascending branch of the descending palatine. The ex-
ternal branches, two or three in number, supply the mucous membrane covering
the lateral wall of the nose, the antrum, and the ethmoid and sphenoid cells.
SuEGicAL Anatomy of the Teiangles of the Neck.
The student having considered the relative anatomy of the large arteries of
the neck and their branches, and the relations they bear to the veins and nerves,
should now examine these structures collectively, as they present themselves in
certain regions of the neck, in each of which important operations are being
constantly performed.
For this purpose, the Sterno-mastoid, or any other muscles that have been
divided in the dissection of the vessels, should be replaced in their normal
position ; the head should be supported by placing a block at the back of the
neck, and the face turned to the side opposite to that which is being examined.
The side of the neck presents a somewhat quadrilateral outline, limited, above,
by the lower border of the body of the jaw, and an imaginary line extending
from the angle of the jaw to the mastoid process ; below, by the prominent
upper border of the clavicle ; in front, by the median line of the neck ; behind,
by the anterior margin of the Trapezius muscle. This space is subdivided into
two large triangles by the Sterno-mastoid muscle, which passes obliquely across
the neck, from the sternum and clavicle, below, to the mastoid process, above.
The triangular space in front of this muscle is called the anterior triangle; and
that behind it, the pjosterior triangle.
Anteeior Teiangulae Space.
The Anterior Triangle is lliriitcd, in front, by a lino extending from the chin
to the sternum; beliirid, 1)y the anterior margin of the Sterno-mastoid; its base,
directed upwards, is formed by the lower border of the body of the jaw, and a
line extending from the angle of the jaw to the mastoid process ; its apex is
below, at the sternum. The space is covered by the integnment, superficial
fascia, Platysma, and deep fascia ; it is crossed by branches of the facial and
ANTERIOR TRIANGULAR SPACE. 487
superficial cervical nerves, and is subdivided into tliree smaller triangles by tbe
Digastric muscle, above, and tbe anterior belly of tlie Omo-liyoid, below. Tliese
smaller triangles are named from below upwards, the inferior carotid, tbe supe-
rior carotid, and the submaxillary triangle.
The Inferior Carotid Trianyle is limited, in front, by the median line of the
neck ; behind, by the anterior margin of the Sterno-mastoid ; above, by the
anterior belly of the Omo-hyoid ; and is covered by the integument, superficial
fascia, Platysma, and deep fascia ; ramifying between which is seen the descending
branch of the superficialis colli nerve. Beneath these superficial structures, are
the Sterno-hyoid and Sterno-thyroid muscles, which, together with the anterior
margin of the Sterno-mastoid, conceal the lower part of the common carotid
artery.^
This vessel is inclosed within its sheath, together with the internal jugular
vein, and pneumogastric nerve ; the vein lying on the outer side of the artery
on the right side of the neck, but overlapping it, or passing directly across it on
the left side ; the nerve lying between the artery and vein, on a plane posterior
to both. In front of the sheath are a few filaments descending from the loop of
communication between the descendens and communicans noni ; behind the
sheath are seen the inferior thyroid artery, the recurrent laryngeal nerve, and
the sympathetic nerve ; and on its inner side, the trachea, the thyroid gland,
much more prominent in the female than in the male, and the lower part of the
larynx. By cutting into the upper part of this space, and slightly displacing
the Sterno-mastoid muscle, the common carotid artery may be tied below the
Omo-hyoid muscle.
Tiie floor of the inferior carotid triangle is formed by the Longus colli muscle
below, and by the Scalenus anticus above (see Fig. 255, p. 371), between which
muscles the vertebral artery and vein will be found passing into the foramen
in the sixth transverse process ; a small portion of the origin of the Eectus capi-
tis anticus major may also be seen in the floor of the space.
The Superior Carotid Trianyle is bounded, behind, by the Sterno-mastoid ;
below by the anterior belly of the Omo-hyoid ; and above, by the posterior belly
of the Digastric muscle. Its floor is formed by parts of the Thyro-hyoid, Hyo-
glossus, and the inferior and middle Constrictor muscles of the pharynx; and it
is covered by the integument, superficial fascia, Platysma, and deep fascia ; rami-
fying between which, are branches of the facial and superficialis colli nerves.
This space contains the upper part of the common carotid artery, which bifur-
cates opposite the upper border of the thyroid cartilage into the external and
internal carotid. These vessels are occasionally somewhat concealed from view
by the anterior margin of the Sterno-mastoid muscle, which overlaps them. The
external and internal carotids lie side by side, the external being the more ante-
rior of the two. The following branches of the external carotid are also met
with in this space : the superior thyroid, running forwards and downwards ; the
lingual directly forwards ; the facial, forwards and upwards ; the occipital, back-
wards ; and the ascending pharyngeal directly upwards on the inner side of the
internal carotid. The veins met with are: the internal jugular, which lies on
the outer side of the common and internal carotid arteries ; and veins corre-
sponding to the above-mentioned branches of the external carotid, viz., the supe-
rior thyroid, the lingual, facial, ascending pharyngeal, and sometimes the occi-
pital ; all of which accompany their corresponding arteries, and terminate in the
internal jugular. The nerves in this space are the following : In front of the
sheath of the common carotid is the descendens noni. The hj^poglossal nerve
' Therefore the carotid artery and jugular vein are not, strictly speaking, contained in this
triangle, since they are covered by the Sterno-mastoid muscle, that is to say, lie behind the ante-
rior border of that muscle, which forms the posterior border of the triangle. But as they lie
very close to the structures which are really contained in the triangle, and whose position it is
essential to remember in operating on this part of the artery, it has seemed expedient to study
the relations of all these parts together.
488 ARTERIES.
crosses botli carotids above, curving round the occipital artery at its origin.
"Within the sheath, between the artery and vein, and behind both, is the pneumo-
gastric nerve; behind the sheath, the sympathetic. On the outer side of the
vessels the spinal accessory nerve runs for a short distance before it pierces
the Sterno-mastoid muscle; and on the inner side of the internal carotid, just
below the hyoid bone, may be seen the superior laryngeal nerve ; and still more
inferiorly, the external laryngeal nerve. The upper part of the larynx and
lower part of the pharynx are. also found in the front part of this space. •
The Suhmaxillary Triangle corresponds to the part of the neck immediately
beneath the body of the jaw. It is bounded, above, by the lower border of the
body of the jaw, the parotid gland and the mastoid process ; below, by the poste-
rior belly of the Digastric and Stylo-hyoid muscles; in front, by the middle line
of the neck. The floor of this space is formed by the anterior belly of the Digas-
tric, the Mylo-hyoid, and Hyo-glossus muscles; and it is covered by the integu-
ment, superficial fascia, Platysma, and deep fascia ; ramifying between which are
branches of the facial and ascending filaments of the superficial cervical nerve.
This space contains, in front, the submaxillary gland, imbedded in the substance
of which are the facial artery and vein, and their glandular branches; beneath
this gland, on the surface of the Mylo-hyoid muscle, are the submental artery,
and the mylo-hyoid artery and nerve. The back part of this space is separated
from the front part by the stylo- maxillary ligament; it contains the external caro-
tid artery ascending deeply in the substance of the parotid gland ; this vessel here
lies in front of, and superlicial to, the internal carotid, being crossed by the facial
nerve, and gives off in its course the posterior auricular, temporal, and internal
maxillary branches ; more deeply is the internal carotid, the internal jugular vein,
and the pneumogastric nerve, separated from the external carotid by the Stylo- •
glossus and Stylo-pharyngeus muscles, and the glosso-pharyngeal nerve.^
Posterior Triangular Space.
The Posterior Triangular Space is bounded, in front by the Sterno-mastoid
muscle; behind, by the anterior margin of the trapezius; its base corresponds
to the upper border of the clavicle; its apex, to the occiput. The space is
crossed about an inch above the clavicle, by the posterior belly of the Omo-hyoid,
which divides it unequally into two, an upper or occipital, and a lower or sub-
clavian triangle.
The Occipital^ the larger of the two posterior triangles, is bounded, in front,
by the Sterno-mastoid ; behind, by the Trapezius ; below, by the Omo-hyoid, Its
fiioor is formed from above downwards by the Splenius, Levator anguli scapulae,
and the middle and posterior Scaleni muscles. It is covered hj the integument,
the Platysma below, the superficial and deep fascias; and crossed, above, by the
ascending branches of the cervical plexus ; the spinal accessory nerve is directed
obliquely across the space from the Sterno-mastoid, which it pierces, to the under
surface of the Trapezius ; below, the descending branches of the cervical plexus
and the transversalis colli artery and transversalis cervicis vein cross the space.
A chain of lymphatic glands is also found running along the posterior border of
the Sterno-mastoid, from the mastoid process to the root of the neck.
Tiie Suhdavian^ the smaller of the two posterior triangles, is bounded, al)ove
by the posterior belly of the Omo-hyoid; below, by the clavicle ; its base, directed
forwards, being formed by the Sterno-mastoid. The size of this space varies
according to the extent of attachment of the clavicular portion of the Sterno-
mastoid and Trapezius muscles, and also according to the height at which the
' 'riiC! snmn roinarlc will fipj)!}' 1o iliis Iriiiiijrlo as was made almut tlic iiifiTior carotid Iriann'lo.
Tlio stnicturos oniitiK^ralcd. as coiitaiiUMl in llic hack part of tlie space, lie, strictly pp(\ikiiig,
l)PtK'at]i the muscles which form the; postcridr l)onn(lary of the triangle; but as it is very impor-
tant to l)ear in mind their close relation to the parotid plaiid and its boundaries (on account of
the frequency of surgical operations on this gland), all these parts are spoken of together.
INTERNAL CAROTID. 489
Omo-]iyoid crosses the neck above tlie clavicle. The height also of this space
varies much, according to the position of the arm, being much diminished by
raising the limb, on account of the ascent of the clavicle, and increased bj drawing
the arm downwards, when that bone is depressed. This space is covered by
the integument, superficial and deep fascia : and crossed by the descending
branches of the cervical plexus. Just above the level of the clavicle, the third
portion of the subclavian artery curves outwards and downwards from the outer
margin of the Scalenus anticus, across the first rib to the axilla. Sometimes
this vessel rises as high as an inch and a half above the clavicle, or to any point
intermediate between this and its usual level. Occasionally, it passes in front
of the Scalenus anticus, or pierces the fibres of that muscle. The subclavian
vein lies behind the clavicle, and is usually not seen in this space ; but it occa-
sionally rises as high up as the artery, and has even been seen to pass with that
vessel behind the Scalenus anticus. The brachial plexus of nerves lies above
the artery and in close contact with it. Passing transversely across the clavicu-
lar margin of the space, are the suprascapular vessels ; and traversing its upper
angle in the same direction, the transverse cervical vessels. The external jugu-
lar vein runs vertically downwards behind the posterior border of the Sterno-
mastoid, to terminate in the Subclavian vein ; it receives the transverse cervical
and suprascapular veins, which occasionally form a plexus in front of the artery,
and a small vein which crosses the clavicle from the cephalic. The small nerve
to the subclavius also crosses this triangle about its middle. A lymphatic gland
is also found in the space.
Internal Caeotid Artery.
The Internal Carotid Artery commences at the bifurcation of the common
carotid, opposite the upper border of the thyroid cartilage, and runs perpen-
dicularly upwards, in front of the transverse processes of the three upper cervi-
cal vertebras, to the carotid foramen in the petrous portion of the temporal bone.
After ascending in it for a short distance, it passes forwards and inwards through
the carotid canal, and, again ascending a little by the side of the sella Turcica,
curves upwards by the anterior clinoid process, where it pierces the dura mater,
and divides into its terminal branches.
This vessel supplies the anterior part of the brain, the eye, and its appen-
dages. Its size, in the adult, is equal to that of the external carotid. In the
child, it is larger than that vessel. It is remarkable for the number of curva-
tures that it presents in different parts of its course. In its cervical portion it
occasionally presents one or two flexures near the base of the skull, whilst
through the rest of its extent it describes a double curvature which resembles
the italic letter s placed horizontally ^. These curvatures most probably
diminish the velocity of the current of blood, by increasing the extent of surface
over which it moves, and adding to the amount of impediment produced from
friction. In considering the course and relations of this vessel, it may be con-
veniently divided into four portions: a cervical, petrous, cavernous, and
cerebral.
Cervical Portion. This portion of the internal carotid is superficial at its
commencement, being contained in the superior carotid triangle, and lying on
the same level as the external carotid, but behind that artery, overlapped by the
Sterno-mastoid, and covered by the Platysma, deep fascia, and integument:
it then passes beneath the parotid gland, being crossed by the hypoglossal nerve,
the Digastric and Stylo-hyoid muscles, and the external carotid and occipital
arteries. Higher up, it is separated from the external carotid by the Stylo-
glossus and Stylo-pharyngeus muscles, the glosso-pharyngeal nerve, and pharyn-
geal branch of the pneumogastric. It is in relation, behind, with the Eectus
capitis anticus major, the superior cervical ganglion of the sympathetic, and
superior laryngeal nerve ; externally, Avith the internal jugular vein, and pneumo-
490
ARTERIES,
gastric nerve; internally^ witli tlie pharynx, tonsil, and ascending pharyngeal
artery.
Petrous Portion. When the internal carotid artery enters the canal in the
petrous portion of the temporal bone, it first ascends a short distance, then
cnrves forwards and inwards, and again ascends as it leaves the canal to enter
the cavity of the skull. In this canal, the artery lies at first anterior to the
Fig. 309. — The Interual Carotid and Yertebral Arteries. Eight Side.
tffAort
tympannrn, from wlii(;li it is separated by a lliin bony lamella, wliich is cribri-
form in the young subject, and often absorbed in old age. It is separated from
the bony wall of the carotid canal by a prolongation of dura mater, and is
surrounded by filaments of the carotid plexus.
INTERNAL CAROTID. 491
Cavernous Portion. The internal carotid artery, in this part of its course, at
first ascends to the posterior clinoid process, then passes forwards bj the side
of the body of the sphenoid bone, being situated on the inner wall of the caver-
nous sinus, in relation, externally, with the sixth nerve, and covered by the
lining membrane of the sinus. The third, fourth, and ophthalmic nerves are
placed on the outer wall of the sinus, being separated from its cavity by the
lining membrane.
Cerebral Portion. On the inner side of the anterior clinoid process the internal
carotid curves upwards, perforates the dura mater bounding the sinus, and is
received into a sheath of the arachnoid. This portion of the artery is on the
outer side of the optic nerve ; it lies at the inner extremity of the fissure of
Sylvius, having the third nerve externally.
Plan of the Relations of the Inteenal Carotid Artery in the Neck.
In Front.
Skin, superficial and deep fasciae.
Parotid gland.
Stylo-glossus and Stylo-pharyngeus muscles.
Glosso-pharyngeal nerve.
Internally.
Externally. / ^^^^,^^^ \ Pharynx.
Internal jugular vein. A^terv Ascending pharyngeal artery.
Pueumogastric nerve. \ / Tonsil.
Behind.
Rectus capitis anticus major.
Sympathetic.
Superior laryngeal nerve.
Peculiarities. The length of the internal carotid varies according to the length of the neck,
and also according to tiie point of bifurcation of the common carotid. Its origin sometimes takes
place from the arch of the aorta ; in such rare instances, this vessel has been found to be placed
nearer the middle line of the neck than the external carotid, as far upwards as the larynx, when
the latter vessel crossed the internal carotid. The course of the vessel, instead of being straight,
may be very tortuous. A few instances are recorded in which this vessel was altogether absent :
in one of these the common carotid passed up the neck, and gave off the usual branches of the
external carotid : the cranial portion of the internal carotid being replaced by two branches of
the internal maxillary, which entered the skull through the foramen rotundum and ovale, and
joined to form a single vessel.
Surgical Anatomy. The cervical part of the internal carotid is sometimes wounded by a stab
or gun-shot wound in the neck, or even occasionally by a stab from within the mouth, as when a
person receives a thrust from the end of a parasol, or falls down with a tobacco-pipe in his mouth.
In such cases a ligature should be applied to the common carotid. The relation of the internal
carotid with the tonsil should be especially remembered, as instances have occurred in which the
artery has been wounded during the operation of scarifying the tonsil, and fatal hemorrhage has
supervened.
■ The branches given off from the internal carotid are :
From the Petrous Portion . Tympanic (internal or deep).
i Arterige Eeceptaculi.
Prom the Cavernous Portion -! Anterior Meningeal.
( Ophthalmic.
( Anterior Cerebral.
rr ^7 n 7 7 -n -L- j Middle Cerebral.
i<rom the Cerebral Portion, i -r> , • /-i ■ .•
I Posterior Communicating.
[ Anterior Choroid.
The cervical portion of the internal carotid gives off no branches.
The tymimnic is a small branch which enters the cavity of the tympanum,
through a minute foramen in the carotid canal, and anastomoses with the tym-
panic branch of the internal maxillary, and with the stylo-mastoid artery.
492
AETERIES,
The arterise receptaculi are numerous small vessels, derived from tlie internal
carotid in tlie cavernous sinus ; tliej supply the pituitary body, the Casserian
ganglion, and the walls of the cavernous and inferior petrosal sinuses. One of
these branches, distributed to the dura mater, is called the anterior meningeal]
it anastomoses with the middle meningeal.
The Ophthalmic Artery arises from the internal carotid, just as that vessel
is emerging from the cavernous sinus, on the inner side of the anterior clinoid
process, and enters the orbit through the optic foramen, below and on the outer
side of the optic nerve. It then passes across the nerve, to the inner wall of the
orbit, and thence horizontally forwards, beneath the lower border of the Superior
oblique muscle to the inner angle of the eye, where it divides into two terminal
branches, the frontal, and nasal.
Branches. The branches of this vessel may be divided into an orbital group,
which are distributed to the orbit and surrounding parts ; and an ocular group,
which supply the muscles and globe of the eye.
Fig. 310. — The Ophthalmic Artery and its Branches, the Eoof of the Orbit having
been removed.
Trmvkd
Ardt.Tior SS.maar>y
£octorictr JS&Ttiovdt
I CarotiSi
Orlntal Group.
Lachrymal.
Supraorbital.
Posterior Ethmoidal.
Anterior Ethmoidal.
Palpebral.
Frontal.
Nasal.
Ocular Groiip.
Muscular.
Anterior Ciliary.
Short Ciliary.
Long Ciliary.
Artcria Centralis Retina).
The lachrymal is the first, and one of the largest branches, derived from the
ophthalmic, arising close to the optic foramen : not un frequently it is given off
fr(;m the artery before it enters the orbit. It accompanies the lachrymal nerve
OPHTHALMIC. 493
along the upper border of the External rectus muscle, and is distributed to the
lachrymal gland. Its terminal branches, escaping from the gland, are distributed
to the upper eyelid and conjunctiva, anastomosing with the palpebral arteries.
The lachrymal artery gives off one or two malar branches ; one of which passes
through a foramen in the malar bone, to reach the temporal fossa, and anasto-
moses with the deep temporal arteries. The other appears on the cheek, and
anastomoses with the transverse facial. A branch is also sent backwards through
the sphenoidal fissure, to the dura mater, which anastomoses with a branch of
the middle meningeal artery.
Peculiarities. 'I'he lachrymal artery is sometimes derived from one of the anterior branches
of the middle meningeal artery.
The suipraorhital artery ., the largest branch of the ophthalmic, arises from that
vessel above the optic nerve. Ascending so as to rise above all the muscles of
the orbit, it passes forwards, with the frontal nerve, between the periosteum and
Levator palpebras ; and passing through the supraorbital foramen, divides into a
superficial and deep branch, which supply the muscles and integument of the
forehead and pericranium, anastomosing with the temporal, the angular branch
of the facial, and the artery of the opposite side. This artery in the orbit sup-
plies the Superior rectus and the Levator palpebrte, sends a branch inwards,
across the pulley of the Superior oblique muscle, to supply the parts at the inner
canthus, and, at the supraorbital foramen, frequently transmits a branch to the
diploe.
The ethmoidal branches are two in number ; posterior and anterior. The
former, which is the smaller, passes through the posterior ethmoidal foramen,
supplies the posterior ethmoidal cells, and, entering the cranium, gives oW a
meningeal branch, which supplies the adjacent dura mater, and nasal branches,
which descend into the nose through apertures in the cribriform plate, anasto-
mosing with branches of the spheno-palatine. The anterior ethmoidal artery
accompanies the nasal nerve through the anterior ethmoidal foramen, supplies
the anterior ethmoidal cells and frontal sinuses, and, entering the cranium,
divides into a meningeal branch, which supplies the adjacent dura mater, and a
nasal branch which descends into the nose, through an aperture in the cribriform
plate.
The palpebral arteries.^ two in number, superior and inferior, arise from the
ophthalmic, opposite the pulley of the Superior oblique muscle; they encircle
the eyelids near their free margin, forming a superior and an inferior arch,
which lie between the orbicularis muscle and tarsal cartilages ; the superior
palpebral inosculating at the outer angle of the orbit with the orbital branch of
the temporal artery, the inferior palpebral with the orbital branch of the infra-
orbital artery, at the inner side of the lid. From this anastomosis, a branch
passes to the nasal duct, ramifying in its mucous membrane, as far as the inferior
meatus.
The frontal artery., one of the terminal branches of the ophthalmic, passes from
the orbit at its inner angle, and ascending on the forehead, supplies the muscles,
' integument, and pericranium, anastomosing with the supraorbital artery.
The nasal artery.^ the other terminal branch of the ophthalmic, emerges from
the orbit above the tendo oculi, and, after giving a branch to the lachrymal sac,
divides into two, one of which anastomoses with the angular artery, the other
branch, the dorsalis nasi, runs along the dorsum of the nose, supplies its entire
surface, and anastomoses with the artery of the opposite side.
The ciliary arteries are divisible into three groups, the short, long, and ante-
rior. The short ciliary arteries., from twelve to fifteen in number, arise from the
ophthalmic, or some of its branches ; they surround the optic nerve as they pass
forwards to the posterior part of the eyeball, pierce the sclerotic coat around the
entrance of the nerve, and supply the choroid coat and ciliary processes. The
long ciliary arteries.^ two in number, also pierce the posterior part of the sclerotic.
494
ARTERIES.
and run forwards, along each, side of tlie eyeball, between tbe sclerotic and
choroid, to the ciliary ligament, where they divide into two branches ; these
form an arterial circle around the circumference of the iris, from which nume-
rous radiating branches pass forwards, in its substance, to its free margin, where
Fig. 311. — The Arteries of the Bnse of the Brain. The right half of the Cerebellum
and Pous have been removed.
they form a second arlcM'ial circle around its ])U])inary margin. Tlie anterior
ciliary arleries arc derived from the muscular branches; they pierce the sclerotic
a shr)rt distance from the cornea, and terminate in the great arterial circle of
llic iris.
OF THE UPPER EXTREMITY. 495
The arteria centralis retinae is one of the smallest branches of tlie ophthalmic
arterj. It arises near the optic foramen, pierces the optic nerve obliquely, and
runs forwards, in the centre of its substance, to the retina, in which its branches
are distributed as far forwards as the ciliary processes. In the human foetus, a
small vessel passes forwards, through the vitreous humor, to the posterior sur-
face of the capsule of the lens.
The muscular branches^ two in number, superior and inferior, supply the
muscles of the eyeball. The superior, the smaller, often wanting, supplies the
Levator palpebrse, Superior rectus, and Superior oblique. The inferior, more
constant in its existence, passes forwards, between the optic nerve and Inferior
rectus, and is distributed to the External and Inferior recti, and Inferior oblique.
This vessel gives off most of the anterior ciliary arteries.
The Cerebral branches of the internal carotid are : the anterior cerebral, the
middle cerebral, the posterior communicating, and the anterior choroid.
The anterior cerebral arises from the internal carotid, at the inner extremity
of the fissure of Sylvius. It passes forwards in the great longitudinal fissure
between the two anterior lobes of the brain, being connected, soon after its origin,
with the vessel of the opposite side by a short anastomosing trunk, about two
lines in length, the anterior com')nunicating . The two anterior cerebral arteries,
lying side by side, curve round the anterior border of the corpus callosum, and
run along its upper surface to its posterior part, where they terminate by
anastomosing with the posterior cerebral arteries. They supply the olfactory
and optic nerves, the under surface of the anterior lobes, the third ventricle, the
anterior perforated space, the corpus callosum, and the inferior surface of the
hemispheres.
The anterior communicating artery is a short branch, about two lines in length,
but of moderate size, connecting together the two anterior cerebral arteries
across the longitudinal fissure. Sometimes this vessel is wanting, the two
arteries joining together to form a single trunk, which afterwards subdivides.
Or the vessel may be wholly, or partially subdivided into two ; frequently, it is
longer and smaller than usual.
The middle cerebral artery^ the largest branch of the internal carotid, passes
obliquely outwards along the fissure of Sylvius, within which it divides into
three branches : an anterior, which supplies the pia mater, investing the surface
of the anterior lobe ; a posterior, which supplies the middle lobe ; and a median
branch, which supplies the small lobe at the outer extremity of the Sylvian
fissure. Near its origin, this vessel gives off numerous small branches which
enter the locus perforatus anticus, to be distributed to the corpus striatum.
The posterior communicating artery arises from the back part of the internal
carotid, runs directly backwards, and anastomoses with the posterior cerebral, a
branch of the basilar. This artery varies considerably in size, being sometimes
small, and occasionally so large that the posterior cerebral may be considered
as arising from the internal carotid rather than from the basilar. It is frequently
larger on one side than on the other side.
The anterior choroid is a small but constant branch which arises from the
back part of the internal carotid, near the posterior communicating artery.
Passing backwards and outwards, it enters the descending horn of the lateral
ventricle, beneath the edge of the middle lobe of the brain. It is distributed to
the hippocampus major, corpus fimbriatum, and choroid plexus.
AETERIES OP THE UPPER EXTREMITY.
The artery which supplies the upper extremity continues as a single trunk
from its commencement down to the elbow ; but different portions of it have
received different names, according to the region throu,gh which it passes. That
part of the vessel which extends from its origin to the outer border of the first
rib, is termed the subclavian; beyond this point to the lower border of the
axilla, it is termed the axillary ; and from the lower margin of the axillary
496 ARTERIES.
space to the bend of the elbow, it is termed hracliial; here, the single trunk
terminates by dividing into two branches, the radial and ulnar, an arrangement
precisely similar to what occurs in the lower limb.
Subclavian Arteries.
The Subclavian Artery on the right side arises from the arteria innominata
opposite the right sterno-clavicular articulation; on the left side it arises from
the arch of the aorta. It follows, therefore, that these two vessels must, in the
first part of their course, differ in their length, their direction, and their relation
with neighboring parts.
In order to facilitate the description of these vessels, more especially in a sur-
gical point of view, each subclavian artery has been divided into three parts.
The first portion, on the right side, ascends obliquely outwards from the origin
of the vessel to the inner border of the Scalenus anticus. On the left side it
ascends vertically to gain the inner border of that muscle. The second part
passes outwards, behind the Scalenus anticus ; and the third part passes from
the outer margin of that muscle, beneath the clavicle, to the lower border of
the first rib, where it becomes the axillary artery. The first portions of these
two vessels differ so much in their course, and in their relation with neighboring
parts, that they will be described separately. The second and third parts are
precisely alilie on both sides.
First Part of the Eight Subclavian Artery. (Figs. 302, 304.)
The right subclavian artery arises from the arteria innominata, opposite the
right sterno-clavicular articulation, passes upwards and outwards across the root
of the neck, and terminates at the inner margin of the Scalenus anticus muscle.
In this part of its course it ascends a little above the clavicle, the extent to
which it does so varying in different cases. It is covered, in front ^ by the integu-
ment, superficial fascia, Platysma, deep fascia, the clavicular origin of the
Sterno-mastoid, the Sterno-hyoid, and Sterno- thyroid muscles, and another layer
of the deep fascia. It is crossed by the internal jugular and vertebral veins, and
by the pneumogastric, the cardiac branches of the symjDathetic, and the phrenic
nerve. Beneath^ the artery is invested by the pleura, and behind^ it is separated
by a cellular interval from the Longus colli, the transverse process of the seventh
cervical or first dorsal vertebra, and the sympathetic : the recurrent laryngeal
nerve winding around the lower and back part of the vessel. The subclavian
vein lies below the subclavian artery, immediately behind the clavicle.
Plan of Eelations of First Portion of Eight Subclavian Artery.
In front.
Clavicular origin of Sterno-mastoid.
Sterno-lij'oid and Storno-tliyroid.
Inlornal jugular and vertebral veins.
Pneumogastric, cardiac, and phrenic nerves.
Beneath.
Pleura.
Behind.
Recurrent laryngeal nerve.
Syin[)athetic.
liongus colli.
'I'ransverse process of scventli cervical or first dorsal vertelira.'
' Tn five ca?;es reeently examined successively the artery was found to lie on the transverse
process of the first dorsal.
SUBCLAVIAN. 497
First Part of tpie Left Subclavian Artery, (Fig. 302.)
The left subclavian artery arises from the end of the transverse portion of the
arch of the aorta, opposite the third dorsal vertebra, and ascends to the inner
margin of the first rib, behind the insertion of the Scalenus anticus muscle.
This vessel is, therefore, longer than the right, situated more deeply in the
cavity of the chest, and directed almost vertically upwards instead of arching
outwards like the vessel of the opposite side.
It is in relation, in front^ with the pleura, the left lung, the pneumogastric,
phrenic, and cardiac nerves, which lie paralled with it, the left carotid artery,
left internal jugular and innominate veins, and is covered by the Sterno-thyroid,
Sterno-hyoid, and Sterno-mastoid muscles ; behind^ it is in relation w4th the
oesophagus, thoracic duct, inferior cervical ganglion of the sympathetic, Longus
colli, and vertebral column. To its inner side are oesophagus, trachea and
thoracic duct ; to its outer side, the pleura.
Plaist of Eelations of First Portion of Left Subclavian Artery.
In Front.
Pleura and left lung,
Pnenmogastric, cardiac, and phrenic nerves.
Left carotid artery.
Left internal jugular and innominate veins.
Sterno-thyroid, Sterno-hyoid, and Sterno-mastoid muscles.
Inner side. /^ .-'i^^^^x Outer side.
Esophagus.
Trachea.
Thoracic duct.
Qllsophagus. I Artery. ] Pleura,
'['rachea. "'
Behind.
CEsophagus and thoracic duct.
Inferior cervical ganglion of sympathetic.
Longus colli and vertebral column.
• Second and Third Parts of the Subclavian Artery. (Fig. 30-i.)
The Second Portion of the Subclavian Artery lies behind the Scalenus anticus
muscle ; it is very short, and forms the highest part of the arch described by
that vessel.
Relations. It is covered, in front., by the integument, Platysma, Sterno-
mastoid, cervical fascia, and by the phrenic nerve, which is separated from the
artery by the Scalenus anticus muscle. Behind.^ it is in relation with the Middle
Scalenus. Above., with the brachial plexus of nerves. JBeloiv, with the pleura.
The subclavian vein lies below and in front of the artery, separated from it by
the Scalenus anticus.
Plan of Relations of Second Portion of Subclavian Artery.
In Front.
Scalenus anticus.
Phrenic nerve.
Subclavian vein.
Above. / ^"]',':J^7;:^" \ Beloio.
Brachial plexus. I Second / Pleura.
Behind.
Plenra and Middle Scalenus.
32
498 ARTERIES.
The Third Portion of the Subclavian Artery passes downwards and outwards
from tlie outer margin of the Scalenus anticus to the lower border of the first
rib, where it becomes the axillary artery. This portion of the vessel is the
most superficial, and is contained in a triangular space, the base of which is
formed in front by the Sterno-mastoid, and the two sides by the Omo-hyoid
above and the clavicle below.
Relations. It is covered, in front^ by the integument, the superficial fascia,
the Platysma, deep fascia; and by the clavicle, the Subclavins muscle, and the
suprascapular artery and vein ; the clavicular descending branches of the cervical
plexus and the nerve to the subclavins pass vertically downwards in front of the
artery. The external jugular vein crosses it at its inner side, and receives the
suprascapular and transverse cervical veins, which occasionally form a plexus
in front of it. The subclavian vein is below the artery, lying close behind the
clavicle. Behind^ it lies on the Middle Scalenus muscle. Above it, and to its
outer side, is the brachial plexus, and Omo-hyoid muscle. Beloiv, it rests on
the outer surface of the first rib.
Plan of Eelations of Third Portion of Subclavian Artery.
Li Front.
Cervical fascia.
External jugular, suprascapular, and transverse cervical veins.
Descending branches of cervical plexus.
Subclavius muscle, suprascapular artery, and clavicle.
Above. / Subclavian \ BeloiO.
Brachial plexus. ( Thfnf I First rib.
Omo-hyoid.
Behind.
Scalenus medius.
Pecxdiaritie^. The Subclavian arteries vary in their origin, their course, and the height to
which they rise in the neci\.
y/ie origin of the right subclavian from the innominate takes place, in some cases, above the
sterno-clavicular articulation; and occasionally, but less frequently, in the cavity of the thorax,
below that joint. Or the artery may arise as a separate trunk from the arch of the aorta. In
such cases it may be either the first, second, third, or even the last branch derived from that
vessel ; in the majority of cases, it is the first or last, rarely the second or third. When it is Die
first bi'anch, it occupies the ordinary position of the innominate artery ; when the second or third,
it gains its usual position by passirig behind the right carotid ; and when the last branch, it arises
from the left extremity of the arch, at its upper or back part, and passes obliquely towards the
right side, usually behind the oesophagus and right carotid, sometimes between the oesophagus
and trachea, to the upper border of the first rib, whence it follows its ordinary course. In very
rare instances, this vessel arises from the thoracic aorta, as low down as the fourth dorsal vertebra.
Occasionally, it perforates the anterior Scalenus; more rarely it passes in front of that muscle:
sometimes the subclavian vein passes with the artery behind the Scalenus. 'I'he artery sometimes
ascends as high as an inch and a half above the clavicle, or any intermediate point between this
and the upper border of the bone, the right subclavian usually ascending higher than the left.
'J'he left subclavian is occasionally joined at its origin with the left carotid.
Surgical Anatomy. The relations of the sulielavian arteries of the two sides having been
examined, the student should direct his attention to consider the best position in which compres-
sion of the vessel may be effected, or in what situation a ligature may be best applied in cases
of aneurism or wound.
('omprcuHion of /.he subclavian artery is required in cases of operations about the shoulder,
in the axilla, or at the upper part of the arm ; and the student will observe; that there is only one
situation in which it can Ijo effectually ap[)lie(], viz., where the artery passes across the outer
surface of the first rib. In order to compress the vessel in this situation, the shoulder should be
depres.sed, and the surgeon grasping the side of the neck, may press with his thumb in the hollow
behind the clavicle downwards against the riii; if from any cause the shoulder cannot be suffi-
ciently depressed, pressure may be made from before backwards, so as to compress the artery
against the middle Scalenus and transverse process of the seventh cervical vertebra. In appro-
SUBCLAVIAN. 499
priate cases, a preliminary incision may be made through the cervical fascia, and the finger may
be pressed down directly upon the artery.
Ligature of the subclavian artery may be required in cases of wounds, or of aneurism in the
axilla; and the third part of the artery is that which is most favorable for an operation, on
account of its being comparatively superficial, and most remote from the origin of the large
branches. In those cases where the clavicle is not displaced, this operation may be performed
with comparative facility ; but where the clavicle is pushed up by a large aneurismal tumor in
the axilla, the artery is placed at a great depth from the surface, which materially increases the
difiSculty of the operation. Under these circumstances, it becomes a matter of importance to
consider the height to which this vessel reaches above the bone. In ordinary cases, its arch is
about half an inch above the clavicle, occasionally as high as an inch and a half, and sometimes
so low as to be on a level with its upper border. If the clavicle is displaced, these variations
will necessarily make the operation more or less difficult, according as the vessel is more or less
accessible.
The chief points in the operation of tying the third portion of the subclavian artery are as
follows : the patient being placed on a table in the horizontal position, and the shoulder depressed
as much as possible, the integument should be drawn downwards upon the clavicle, and an incision
made through it upon that bone from the anterior border of the Trapezius to the posterior border
of the Sterno-mastoid, to which may be added a short vertical incision meeting the preceding in
its centre ; the Platysma and cervical fascia should be divided upon a director, and if the interval
between the 'IVapezius and Sterno-mastoid muscles be insufficient for the performance of the
operation, a portion of one or both may be divided. The external jugular vein will now be seen
towards the inner side of the wound : this and the suprascapular and traiisverse cervical veins
which terminate in it should be held aside, and if divided, both ends should be tied : the supra-
scapular artery should be avoided, and the Omo-hyoid muscle must now be looked for, and held
aside if necessary. In the space beneath this muscle, careful search must be made for the vessel;
the deep fascia having been divided with the finger-nail or silver scalpel, the outer margin of the
Scalenus muscle must be felt for, and the finger being guided by it to the first rib, the pulsation
of the subclavian artery will be felt as it passes over the rib. 'i'he aneurism needle may then be
passed around the vessel from before backwards, by which means the vein will be avoided, care
being taken not to include a branch of the brachial plexus instead of the artery in the ligature.
If the clavicle is so raised by the tumor that the application of the ligature cannot be effected
in this situation, the artery may be tied above the first rib, or even behind the Scalenus muscle ;
the difficulties of the operation in such a case will be materially increased, on account of the
greater depth of the artery, and the alteration in position of the surrounding parts.
The second part of the subclavian artery, from being that portion which rises highest in the
neck, has been considered favorable for the application of the ligature, when it is difficult to tie
the artery in the third part of its course. There are, however, many objections to the operation
in this situation. It is necessary to divide the Scalenus anticus muscle, upon which lies the
phrenic nerve, and at the inner side of which is situated the internal jugular vein ; and a wound
of either of these structures might lead to the most dangerous consequences. Again, the artery
is in contact, below, with the pleui'a, which must also be avoided ; and, lastly, the proximity of
so many of its larger branches arising internal to this point, must be a still further objection to
the operation. If, however, it has been determined to perform the operation in this situation, it
should be remembered that it occasionally happens, that the artery passes in front of the Scalenus
anticus, or through the fibres of that muscle ; and that the vein sometimes passes with the artery
behind the Scalenus anticus.
In those cases of aneurism of the axillary or subclavian artery which encroach upon the outer
portion of the Scalenus muscle to such an extent that a ligature cannot be applied in that situa-
tion, it may be deemed advisable, as a last resource, to tie the first portion of the subclavian
artery. On the left side, this operation is almost impracticable; the great depth of the artery
from the surface, its intimate relation with the pleura, and its close proximity to the thoracic
duct and to so many important veins and nerves, present a series of difficulties which it is next
to impossible to overcome.' On the right side, the operation is practicable, nnd has been per-
formed, though not with success. The main objection to the operation in this situation is the
sniallness of the interval which usually exists between the commencement of the vessel and the
origin of the nearest branch. This operation may be performed in the following manner :— The
patient being placed on the table in the horizontal position, with the neck extended, an incision
should be made parallel with the posterior border of the inner part of the clavicle, and a second
along tlie inner border of the Sterno-mastoid. meeting the former at an angle. 'Jlie sternal attach-
ment of the Sterno-mastoid may now he divided on a director, and turned outwards; a few small
arteries and veins, and occasionally the anterior jugular, must be avoided, and the Sterno-hyoid
and Sterno-thyroid muscles divided in the same manner as the preceding muscle. After tearing
through the deep fascia with the finger-nail, the interna! jugular veinwill be seen crossing the
subclavian artery; this should be pressed aside, and the artery secured by passing the needle
from below upwards, by which the pleura is more effectually avoided. The exact position of the
vagus nerve, the recurrent laryngeal, the phrenic and sympathetic nerves should be remembered.
The operation was, however, performed in New York, by Dr. J. K. Rodffers, and the case is
related in A Sydem of Surgery, edited by T. Holmes, 2d ed. vol. iii. pp. 620, etc.
500
ARTERIES.
and the ligature slioiild be applied near the origin of the vertebral, in order to afford as much
room as possible for the formation of a coagulum between the ligature and the origin of the vessel.
It should be remembered, that the right subclavian artery is occasionally deeply placed in the
first part of its course, when it arises from the left side of the aortic arch, and passes in such cases
behind the oesophagus, or between it and the trachea.
Collateral Circulation. After ligature of the third part of the subclavian artery, the col-
lateral circulation is mainly established by three sets of vessels, thus described in a dissection : —
" 1. A posterior set, consisting of the suprascapular and posterior scapular branches of the
subclavian, which anastomosed with the infrascapular from the axillary.
" 2. An internal set produced by the connection of the internal mammary on the one hand,
with the short and long thoracic arteries, and the infrascapular on the other.
" 3. A middle or axillary set, which consisted of a number of small vessels derived from branches
of the subclavian, above ; and passing through the axilla, to terminate either in the main trunk,
or some of the branches of the axillary below. This last set presented most conspicuously the
peculiar character of newly-formed, or, rather, dilated arteries, being excessively tortuous, and
forming a complete plexus.
" The chief agent in the restoration of the axillary artery below the tumor, was the infra-
scapular artery, which communicated most freely with the internal mammary, suprascapular, and
posterior scapular branches of the subclavian, from all of which it received so great an iiitlux of
blood as to dilate it to three times its natural size."'
Fig. 312.— Plan of the Branches of the
Right Subclavian Artery.
Branches of the Subclavian Arteey,
These are four in number. Three arise from the first portion of the vessel,
the vertebral, the internal mammary, and the thyroid axis ; and one from the
second portion, the superior intercostal.
The vertebral arises from the upper and
back part of the first portion of the artery ;
the thyroid axis from the front, and the
internal mammary from the under part of
this vessel. The superior intercostal is
given off from the upper and back part of
the second portion of the artery. On the
left side, the second portion usuall}^ gives
olf no branch, the superior intercostal
arising at the inner side of the Scalenus
anticus. On both sides of the bod}?", the
first three branches arise close together at
the inner margin of the Scalenus anticus ;
in the majority of cases, a free interval of
half an inch to an inch existing between
the commencement of the artery and the
origin of the nearest branch ; in a smaller number of cases, an interval of more
than an inch exists, never exceeding an inch and three-quarters. In a very few
instances, the interval has been found less than half an inch.
The Vertebral Artery (Fig. 309) is generally the first and largest branch
of the subclavian ; it arises from the upper and back part of the first portion of
the vessel, and, passing upwards, enters the foramen in the transverse process
of the sixth cervical vertebra,^ and ascends through the foramina in the trans-
verse processes of all the vertcbno above this. Above the upper border of the
axis, it inclines outwards and upwards to the foramen in the transverse process
of the atlas, through wliicli it passes; it thou winds backwards behind its
articular process, runs in a deep groove on tlic upper surfiice of the posterior
arch of this bone, and, piercing the posterior occipito-atloid ligament and dura
mater, enters the skull llu'ongli 1lie fornincn mngniini. Tt then passes in front
' Giiy'a TTospi/al Fcpnrts. vol. i., 1836. Case of axillary aneurism, in which Mr. Aslon Ivey
had tied the subclavian artery on Ihe outer edge of the .Scalenus muscle, twelve years previously.
2 'I'ho vertebral artery sometimes outers the foramen in the transverse process of the fifth
vertebra. Dr. Smyth, who tied Ihi.s artery in the living subject, found it, in one of his dissections,
passing into the ruramen in the seventh vertebra.
VERTEBEAL. 501
of tlie medulla oblongata, and unites witli the vessel of the opposite side at tlie
lower border of the pons Varolii, to form the basilar artery.
At its origin, it is situated behind the internal jugular vein, and inferior
thj^roid artery ; and, near the spine, lies between the Longus colli and Scalenus
anticus muscles, having the thoracic duct in front of it on the left side. Within
the foramina formed by the transverse processes of the vertebrte, it is accom-
panied by a plexus of nerves from the sympathetic, and lies between the verte-
bral vein, which is in front, and the cervical nerves, which issue from the inter-
vertebral foramina behind it. Whilst winding round the articular process of
the atlas, it is contained in a triangular space formed by the Eectus posticus
major, the Superior and the Inferior oblique muscles; and is covered by the
Eectus posticus major and Complexus. Within the skull, as it winds round the
medulla oblongata, it is placed between the hypoglossal nerve and the anterior
root of the suboccipital nerve.
Branches. These may be divided into two sets, those given off in the neck,
and those within the cranium.
Cervical Branches. Cranial Branches.
Lateral Spinal. Posterior Meningeal.
Muscular. Anterior Spinal.
Posterior Spinal.
Inferior Cerebellar.
The lateral spinal branches enter the spinal canal through the intervertebral
foramina, each dividing into two branches. Of these one passes along the jroots
of the nerves to supply the spinal cord and its membranes, anastomosing with
the other spinal arteries ; the other is distributed to the posterior surface of the
bodies of the vertebrae.
Muscular branches are given off to the deep muscles of the neck, where the
vertebral artery curves round the articular process of the atlas. They anasto-
mose with the occipital and deep cervical arteries.
The posterior meningeal are one or two small branches given off' from the
vertebral opposite the foramen magnum. They ramify between the bone and
dura mater in the cerebellar fossge, and supply the falx cerebelli.
The anterior spinal is a smaller branch, larger than the posterior spinal, which
arises near the termination of the vertebral, and unites with its fellow of the
opposite side in front of the medulla oblongata. The single trunk, thus formed,
descends a short distance on the front of the spinal cord, and joins with a suc-
cession of small branches which enter the spinal canal through some of the
intervertebral foramina ; these branches are derived from the vertebral and
ascending cervical in the neck ; from the intercostal, in the dorsal region ; and
from the lumbar, ilio-lumbar, and lateral sacral arteries in the lower part of the
spine. They unite, by means of ascending and descending branches, to form a
single anterior median artery, which extends as far as the lower part of the spinal
cord. This vessel is placed beneath the pia mater along the anterior median
fissure ; it supplies that membrane, and the substance of the cord, and sends off'
its branches at its lower part to be distributed to the cauda equina.
The posterior spinal arises from the vertebral, at the side of the medulla
oblongata ; passing backwards to the posterior aspect of the spinal cord, it
descends on either side, lying behind the posterior roots of the spinal nerves:
and is reinforced by a succession of small branches, which enter the spinal canal
through the intervertebral foramina, and by which it is continued to the lower
part of the cord, and to the cauda equina. Branches from these vessels form a
free anastomosis round the posterior roots of the spinal nerves, and communicate,
by means of very tortuous transverse branches, with the vessel of the opposite
side. At its commencement, it gives off an ascending branch, which terminates
on the side of the fourth ventricle.
The inferior cerebellar artery (Fig. 311), the largest branch of the vertebral,
502 ARTERIES.
winds backwards round tlie upper part of tlie medulla oblongata, passing between
the origin of the spinal accessory and pneumogastric nerves, over tlie'restiform
body to the under surface of the cerebellum, where it divides into two branches :
an internal one, which is continued backwards to the notch between the two
hemispheres of the cerebellum ; and an external one, which supplies the under
surface of the cerebellum, as far as its outer border, where it anastomoses with
the superior cerebellar. Branches from this artery supply the choroid plexus
of the fourth ventricle.
The Basilar artery^ so named from its position at the base of the skull, is a
single trunk formed by the junction of the two vertebral arteries ; it extends
from the posterior to the anterior border of the pons Variolii, where it divides
into two terminal branches, the posterior cerebral arteries. Its branches are,
on each side, the following :
Transverse. Superior Cerebellar.
Anterior Cerebellar. Posterior Cerebral.
The transverse branches supply the pons Varolii and adjacent parts of the
brain; one (internal auditory) accompanies the auditory nerve into the internal
auditory meatiis ; and another, of larger size, passes along the crus cerebelli, to
be distributed to the anterior border of the under surface of the cerebellum. It
is called the anterior inferior cerebellar artery.
The superior cerehellar arteries arise near the termination of the basilar. They
wind round the crus cerebri, close to the fourth nerve, and arriving at the upper
surface of the cerebellum, divide into branches which ramify in the pia mater
and anastomose with the inferior cerebellar. Several branches are given to the
pineal gland, and also to the velum interpositum.
H^YiQ posterior cerebral arteries^ the two terminal branches of the basilar, are
larger than the preceding, from which they are separated near their origin by
the third nerves. Winding round the crus cerebri, they pass to the under sur-
face of the posterior lobes of the cerebrum, which they supply, anastomosing
with the anterior and middle cerebral arteries. Near their origin, they receive
the posterior commuDicating arteries from the internal carotid, and give off
nu.merous branches which enter the posterior perforated space : they also give
off a branch, the posterior choroid, which supplies the velum interpositum and
choroid plexus, entering the interior of the brain beneath the posterior border
of the corpus callosum.
Circle of Willis. The remarkable anastomosis which exists between the
branches of the internal carotid and vertebral arteries at the base of the brain,
constitutes the circle of Willis. It is formed, in front, by the anterior cerebral
and anterior communicating arteries; on each side, by the trunk of the internal
carotid, and the posterior communicating; behind by the posterior cerebral, and
point of the basilar. It is by this anastomosis that the cerebral circulation is
equalized, and provision made for effectually carrying it on if one or more
of the branches are obliterated. The parts of the brain included within this
arterial circle are, the lamina cinerea, the commissure of the optic nerves, the
infundibulum, the tuber cincreum, the cor2)ora albicantia, and the posterior
perforated space.
Tlic TrnnioiD Axis (Fig. 304) is a short thick trunk, which arises from the
fore part of the first portion of the subclavian artery, close to the inner border
of the Scalenus anticus muscle, and divides, almost immediately after its origin,
into three branches, the inferior thyroid, su]orasca]")ular, and transvcrsalis colli.
The Inkkiuok Tiiyroid Artery passes u])Avards, in a serpentine course,
beliind tlie slicalli of the common carotid vessel and symjathetic nerve (the
middle cervical ganglion resting upon it), and is distributed to the under surface
of the thyroid gland, anastomosing with lli(^ su))crior thyroid, and with the
corresponding artery of the opposite side. lis l)ranchcs arc the
Laryngeal. (l^'si >] >! lagcal.
Tracheal. Ascending Cervical.
TKANSVEESALIS COLLI.
503
Tile laryngeal brancli ascends upon the tracliea to the back part of the larynx,
and supplies the muscles and mucous membrane of this part.
The tracheal branches are distributed upon the trachea, anastomosing below
with the bronchial arteries.
The oesophageal branches are distributed to the oesophagus.
The ascending cervical is a small branch which arises from the inferior thyroid,
just where that vessel is passing behind the common carotid artery, and runs
up the neck in the interval between the Scalenus anticus and Eectus anticus
major. It gives branches to the muscles of the neck, which communicate with
those sent out from the vertebral, and sends one or two through the interverte-
bral foramina, along the cervical nerves, to supply the bodies of the vertebrae,
the spinal cord, and its membranes.
The Suprascapular Artery, smaller than the transversalis colli, passes ob-
liquely from within outwards, across the root of the neck. It at first lies on
the lower part of the Scalenus anticus, being covered by the Ster no- mastoid; it
then crosses the subclavian artery, and runs outwards behind and parallel with
the clavicle and Subclavian muscle, and beneath the posterior belly of the Omo-
hyoid, to the superior border of the scapula, where it passes over the transverse
ligament of the scapula, to the supraspinous fossa. In this situation it lies close
to the bone, and ramifies between it and the Supraspinatus muscle, to which it
is mainly distributed, giving off a communicating branch, which crosses the neck
of the scapula, to reach the infraspinous fossa, where it anastomoses with the
dorsal branch of the subscapular artery. Besides distributing branches to the
Sterno-mastoid, and neighboring muscles, it gives off a supra-acromial branch,
which, piercing the Trapezius muscle, supplies the cutaneous surface of the aero-
Fig. 313. — The Scapular and Circumflex Arteries.
Sesterter Scafialar
Acromial Bravch
cf TkcTaeice-AcTcmialia
Tcrmijiaflon o^
i>ulsca/Mlar
mion, anastomosing with the acromial thoracic artery. As the artery passes
over the transverse ligament of the scapula, a branch descends into the subscapu-
lar fossa, ramifies beneath that muscle, and anastomoses with the posterior and
subscapular arteries. It also supplies the shoulder -joint.
The Transversalis Colli passes transversely outwards, across the upper
part of the subclavian triangle, to the anterior margin of the Trapezius muscle,
beneath which it divides into two branches, the superficial cervical, and the
posterior scapular. In its passage across the neck, it crosses in front of the
504 ARTERIES.
Scaleni muscles and the bracliial plexus, between the divisions of wliicli it some-
times passes, and is covered by the Platjsma, Sterno-mastoid, Omo-hyoid, and
Trapezius muscles.
The superficial cervical ascends beneath the anterior margin of the Trapezius,
distributing branches to it, and to the neighboring muscles and glands in the
neck.
The posterior scapular^ the continuation of the trans versalis colli, passes
beneath the Levator anguli scapula to the posterior angle of the scapula, and
descends along the posterior border of that bone as far as the inferior angle,
where it anastomoses with the subscapular branch of the axillary. In its
course it is covered by the Ehomboid muscles, supplying these, the Latissimus
dorsi and Trapezius, and anastomosing with the suprascapular and subscapular
arteries, and with the posterior branches of some of the intercostal arteries.
Peculiarities. The superficial cervical fi-equontly arises as a separate branch from the thy-
roid axis ; and the posterior scapular, from the third, more rarely from the second, part of the
subclavian.
The Inteenal Mammary arises from the under surface of the first portion
of the subclavian artery, opposite the thyroid axis. It descends behind the
clavicle to the inner surface of the anterior wall of the chest, resting u.pon the
costal cartilages a short distance from the margin of the sternum ; and, at the
interval between the sixth and seventh cartilages, divides into two branches, the
musculo-phrenic, and superior epigastric.
At its origin, it is covered by the internal jugular and subclavian veins, and
crossed by the phrenic nerve. In the upper part of the thorax, it lies upon the
costal cartilages, and internal Intercostal muscles in front, and is covered by the
pleura behind. At the lower part of the thorax, the Triangularis sterni sepa-'
rates the artery from the pleura. It is accompanied by two veins, which join
at the upper part of the thorax into a single trunk.
The branches of the internal mammary are — •
Comes ISTervi Phrenici (superior phrenic). Anterior Intercostal.
Mediastinal. Perforating.
Pericardiac. Musculo-phrenic.
Sternal. Superior Epigastric.
The comes nervi phrenici {superior pjlirenic) is a long slender branch, which
accompanies the phrenic nerve, between the pleura and pericardium, to the
Diaphragm, to which it is distributed ; anastomosing with the other phrenic
arteries from the internal mammary, and abdominal aorta.
The mediastinal branches are small vessels, which are distributed to the areolar
tissue in the anterior mediastinum, and the remains of the thymus gland.
The pericardiac branches supply the upper part of the pericardium, the lower
part receiving branches from the musculo-phrenic artery. Some steniaZ branches
are distributed to the Triangularis sterni, and both surfaces of the sternum.
The anterior intercostal arteries supply the live or six upper intercostal spaces.
The branch corresponding to each space passes outwards, and soon divides into
two, which run along the opposite borders of the ribs, and inosculate with the
intercostal arteries from the aorta. They are at first situated between the pleura
and the internal Intercostal muscles, and then between the two layers of those
muscles. They supply the Intercostal and Pectoral muscles, and the mammary
gland.
The 'perforatiwj arteries correspond to the five or six upper intercostal spaces.
They arise from the internal mammary, pass forwards through the intercostal
spaces, and, curving outwards, snp])ly the Pcctoralis major, and the integument.
Those which correspond to the first ihrec sjiaccs, arc distributed to the mam-
mary gland. In females, during ladiilinn, llicsc brunches are of large size.
The musculo-phrenic artery is directed ()bli(|ucly downwards and outwards,
behind the cartilages of the false ribs, perforating the Diaphragm at the eighth
AXILLA. 505
or nintli rib, and terminating, considerably reduced in size, opposite tlie last
intercostal space. It gives off anterior intercostal arteries to each, of tbe inter-
costal spaces across wbicli it passes ; these diminish in size as the spaces decrease
in length, and are distributed in a manner precisely similar to the anterior in-
tercostals from the internal mammary. The musculo-phrenic also gives branches
backwards to the Diaphragm, and downwards to the abdominal muscles.
The superior epigastric continues in the original direction of the internal
mammary, descends behind the Kectus muscle, and, perforating its sheath,
divides into branches which supply the Rectus, anastomosing with the epi-
gastric artery from the external iliac. Some vessels perforate the sheath of the
Rectus, and supply the muscles of the abdomen and the integument, and a small
branch which passes inwards upon the side of the ensiform appendix, anasto-
moses in front of that cartilage with the artery of the opposite side.
The SuPERiOE Intercostal (Fig. 309) arises from the upper and back part
of the subclavian artery, behind the anterior scalenus on the right side, and to
the inner side of the muscle on the left side. Passing backwards, it gives off
the deep cervical branch, and then descends behind the pleura in front of the
necks of the first two ribs, and inosculates with the first aortic intercostal. In
the first intercostal space, it gives off a branch which is distributed in a manner
similar to the distribution of the aortic intercostals. The brancii for the second
intercostal space usually joins with one from the first aortic intercostal. Each
intercostal gives off a branch to the posterior spinal muscles, and a small one,
which passes through the corresponding intervertebral foramen to the spinal
cord and its membranes.
The deep cervical branch [profunda cervicis) arises, in most cases, from the
superior intercostal, and is analogous to the posterior branch of an aortic inter-
costal artery. Passing backwards, between the transverse process of the seventh
cervical vertebra and the first rib, it runs up the back part of the neck, between
the Complexus and Semispinalis colli muscles, as high as the axis, supplying
these and adjacent muscles, and anastomosing with the arteria princeps cervicis
of the occipital, and with branches which pass outwards from the vertebral.
Surgical Anatomy of the Axilla.
The Axilla is a pyramidal space, situated between the upper and lateral part
of the chest, and the inner side of the arm.
Boundaries. Its ajoea?, which is directed upwards towards the root of the
neck, corresponds to the interval between the two scaleni muscles on the first
rib. The hase^ directed downwards, is formed by the integument, and a thick
layer of fascia, extending between the lower border of the Pectoralis major in
front and the lower border of the Latissimus dorsi behind ; it is broad internally,
at the chest, but narrow and pointed externally, at the arm. The anterior
boundary is formed by the Pectoralis major and minor muscles, the former
covering the whole of the anterior wall of the axilla, the latter covering only its
central part. The posterior boundary^ which extends somewhat lower than the
anterior, is formed by the Subscapularis above, the Teres major and Latissimus
dorsi below. On the inner side, are the first four ribs with their corresponding
Intercostal muscles, and part of the Serratus magnus. On the otiter side, where
the anterior and posterior boundaries converge, the space is narrow, and bounded
by the humerus, the Coraco-brachialis and Biceps muscles.
Contents. This space contains the axillary vessels, and brachial plexus of
nerves, with their branches, some branches of the intercostal nerves, and a large
number of lymphatic glands, all connected together by a quantity of fat and
loose areolar tissue.
Their Position. The axillary artery and vein, with the brachial plexus of
nerves, extend obliquely along the outer boundary of the axillary space, from
its apex to its base, and are placed much nearer the anterior than the posterior
506
AETERIES.
wall, tlie vein lying to the inner or thoracic side of the artery, and altogether
concealing it. At the fore part of the axillary space, in contact with the Pectoral
muscles, are the thoracic branches of the axillary artery, and along the anterior
margin of the axilla the long thoracic artery extends to the side of the chest.
At the back part, in contact with the lower margin of the Subscapularis muscle,
are the subscapular vessels and nerves : winding around the lower border of
this muscle, is the dorsalis scapulee artery and veins ; and towards the outer
extremity of the muscle, the posterior circumflex vessels and the circumflex
nerve are seen curving backwards towards the shoulder.
Along the inner or thoracic side no vessel of any importance exists, the up]3er
part of the space being crossed merely by a few small branches from the superior
thoracic artery. There are some important nerves, however, in this situation,
viz., the posterior thoracic or external respiratory nerve, descending on the
surface of the Serratus magnus, to which it is distributed ; and perforating the
upper and anterior part of this wall, the intercosto-humeral nerve or nerves,
passing across the axilla to the inner side of the arm.
The cavity of the axilla is filled by a quantity of loose areolar tissue, a large
number of small arteries and veins, all of which are, however, of inconsiderable
size, and numerous lymphatic glands ; these are from ten to twelve in number,
and situated chiefly on the thoracic side, and lower and back part of this space.
Fig. 314. — The Axillary Artery, and its Branches.
^y ' ' A/ V
The student shoulil attentively consider tlio relation of llic vessels and nerves
in tlie several parts of the axilla.; for it not unfrcqucntly hap])cns that the sur-
geon is called npon to extirpate diseased glands, or to remove a tumor from this
situation. In )).rfMi-niing such an operation, it will be necessary to proceed with
much caution in the direction of the outer wall and apex of the space, as here
the axillary vessels will be in danger of being wounded. Towards the posterior
AXILLARY. 507
wall, it will be necessary to avoid the subscapular, dorsalis scapulae, and posterior
circumflex vescels, and, along the anterior wall, the thoracic branches. It is
only along the inner or thoracic wall, and in the centre of the axillary cavity,
that there are no vessels of any importance ; a fortunate circumstance, for it is in
this situation more especially that tumors requiring removal are usually situated.
The Axillaey Artery.
The Axillary Artery, the continuation of the subclavian, commences at the
lower border of the first rib, and terminates at the lower border of the tendons
of the Latissimus dorsi and Teres major muscles, where it takes the name of
brachial. Its direction varies with the position of the limb: when the arm lies
by the side of the chest, the vessel forms a gentle curve, the convexity being
upwards and outwards ; when it is directed at right angles with the trunk, the
vessel is nearly straight ; and when it is elevated still higher, the artery describes
a curve, the concavity of which is directed upwards. At its commencement the
artery is very deeply situated, bu.t near its termination is superficial, being
covered only by the skin and fascia. The description of the relations of this
vessel is facilitated by its division into three portions : the first portion being
that above the Pectoralis minor ; the second portion, behind ; and the third
below, that muscle.
The first portion of the axillary artery is in relation, in front^ with the cla-
vicular portion of the Pectoralis major, the costo-coracoid membrane, the Sub-
clavius, and the cephalic vein ; behind^ with the first intercostal space, the corre-
sponding Intercostal muscle, the first serration of the Serratus magnus, and the
posterior thoracic nerve; on its outer side^ with the brachial plexus, from which
it is separated by a little cellular interval ; on its inner ^ or thoracic side, with
the axillary vein.
Eelations of the First Portion of the Axillary Artery.
In front.
Pectoralis major.
Costo-coracoid membrane.
Subclavins.
Cephalic vein.
Outer side. i Axillary \ Inner side.
Artery.
Brachial plexus. \First portion./ Axillary vein.
Behind.
First intercostal space, and Intercostal muscle.
First serration of Serratus magnus.
Posterior thoracic nerve.
The sesond portion of the axillary artery lies behind the Pectoralis minor. It
is covered, in front, by the Pectoralis major and minor muscles: behind, it is
separated from the Subscapularis by a cellular interval; on the inner side is the
axillary vein. The brachial plexus of nerves surrounds the artery, and sepa-
rates it from direct contact with the vein and adjacent muscles.
508 ARTERIES.
Eelations of the Second Portion of the Axillary Artery.
In front.
Pectoralis major and minor.
Outer side. I Artery. j Inner side.
Outer cord of plexus. y iwrtfon. / Axillary vein.
Inner cord ot piexus.
Behind.
Snbscapulavis.
Posterior cord of plexus.
Tlie third portion of tlie axillary arter}^ lies below the Pectoralis minor. It
is in relation, in front.^ witli the lower part of the Pectoralis major above, being
covered only by the integument and fascia below ; hehind., with the lower part
of the Subscapularis, and the tendons of the Latissimus dorsi and Teres major;
on its outer side^ 'with the Coraco-brachialis ; on its inner .^ or thoracic side, with
the axillary vein. The nerves of the brachial plexus bear the following relation
to the artery in this part of its course : on the outer side is the median nerve,
and the musculo-cutaneous for a short distance ; on the inner-side., the ulnar, the
internal, and lesser internal cutaneous nerves; and behind the musculo-spiral, and
circumflex, the latter extending only to the lower border of the Subscapularis
muscle.
Eelations of the Third Portion of the Axillary Artery.
In front.
Inlegument and fascia.
Pectoralis major.
Outer side. / 4^iii„,.,r \ Inner side.
Coraco-brachialis. [ Artery. \ Ulnar nerve.
Median nerve. y ^" ^'"'^ '°"y Internal cutaneous nerves.
Musculo-cutaneous nerve. \ / Axillary vein.
Behind.
Subscapularis.
Tendons of Latissimus dorsi and Teres major.
Musculo-spiral, and circumflex nerves.
PecAdiarities. The axillary artery, in about one case out of every ten, gives off a large
branch, which forms cither one of the arteries of the forearm, or a large muscular trunk. In the
first set of cases, this artery is most frequently the radial (1 in 83), sometimes the ulnar (1 in 72),
and, very rarely, the interosseous (I in 506). In the second set of cases, the trunk has been
found to give origin to the subscapular, circumflex, and profunda arteries of the arm. Some-
times, only one of the circumflex, or one of the profunda arteries, arose from the trunk. In
these cases, the brachial plexus surrounded the trunk of the branches, and not the main vessel.
Surgical Anatomy. The student, having carefully examined the relations of the a.xillary
artery in its various parts, should now consider in what situation compression of this vessel may
be most easily effected, and the best position for the application of a ligature to it when
necessary.
Cornpres.v'on of the vessel is required in the removal of tumors, or in amputation of the ujiper
])art of the arm; and the only situation in which this can l)e effectually made, is in llic luwer
part of its course ; by pressing on it in this situation from wilhiii outwards against the humerus,
the circulation may bo effectually arrested.
Tlie application (fa lUjal.ure to the axillary artery may 1)0 required in cases of aneurism of
the upper part of the brachial ; and there arc only two situations in which it can be secured,
viz., in the first and in the third parts of its course ; for the axillary artery at its central part
is so deeply seated, and, at the same time, so closely surrounded with large nervous trunks, that
the application of a ligature to it in that situation would be almost inii)racticable.
In the lliiril jxirt of its course, the operation is most simple, and may lie performed in the
following iniinmr: Tlic jiatient being placed on a bed, and the arm se])ara1e(l from lh(> side,
with the hand .-njiinulid, the head of the humerus is felt for, and an incision made through the
AXILLARY. 509
integument over it, about two inches in length, a little nearer to the anterior than the posterior
fold^f the axilla. After carefully dissecting through the areolar tissue and fascia, the median
nerve and axillary vein are exposed ; the former having been displaced to the outer, and the
latter to the inner side of the arm, the elbow being at the same time bent, so as to relax the
structures, and facilitate their separation, the ligature may be passed round the artery from the
ulnar to the radial side. This portion of the artery is occasionally crossed by a muscular slip
derived from the Latissimus dorsi, which may mislead the surgeon during an operation. The
occasional existence of this muscular fasciculus was spoken of in the description of the muscles.
It may easily be recognized by the transverse direction of its fibres.
The first portion of the axillary artery may be tied in cases of aneurism encroaching so far
upwards that a ligature cannot be applied in the lower part of its course. Notwithstanding that
this operation has been performed in some few cases, and with success, its performance is attended
with much difficulty and danger. The student will remark that, in this situation, it would be
necessary to divide a thick muscle, and, after separating the costo-coracoid membrane, the artery
would be exposed at the bottom of a more or less deep space, with cephalic and axillary veins in
such relation with it as must render the application of a ligature to this part of the vessel particu-
larly hazardous. Under such circumstances it is an easier, and, at the same time, more advisable
operation, to tie the subclavian artery in the third part of its course.
In a case of wound of the vessel, the general practice of cutting down upon, and tying it above
and below the wounded point, should be adopted in all cases.
Collateral circulation after ligature of the axillary artery. If the artery be tied above the
origin of the acromial thoracic, the collateral circulation will be carried on by the same branches
as after the ligature of the subclavian ; if at a lower point, between the acromial thoracic and
subscapular arteries, the latter vessel, by its free anastomoses with the other scapular arteries,
branches of the subclavian, will become the chief agent in carrying on the circulation, to which
the long thoracic, if it be below the ligature, will materially contribute, by its anastomoses with
the intercostal and internal mammary arteries. If the point included in the ligature be below
the origin of the subscapular arterj^ the anastomoses are less free. The chief agents in restoring
the circulation, will be the posterior circumflex, by its anastomoses with the suprascapular and
acromial thoracic, and the communications between the subscapular and superior profunda, which
will be afterwards referred to as performing the same office after ligature of the brachial. The
cases in which the operation has been performed are few in number, and no published account of
dissection of the collateral circulation appears to exist.
The branches of the axillary artery are, — •
7-, _, 7-, ( Superior thoracic.
From 1st Part | Acromial thoracic.
„ o 7 n i Thoracica longa.
From M Part -j Thoracica alaris.
i Subscapular,
From 2>d Part ' I Anterior circumflex.
( Posterior circumflex.
The superior thoracic is a small artery, which arises from the axillary sepa-
rately, or by a common trunk with the acromial thoracic. Running forwards
and inwards along the upper border of the Pectoralis minor, it passes between
it and the Pectoralis major to the side of the chest. It supplies these muscles,
and the parietes of the thorax, anastomosing with the internal mammary and
intercostal arteries.
The acromial thoracic is a short trunk, which arises from the fore part of the
axillary artery. Projecting forwards to the upper border of the Pectoralis
minor, it divides into three sets of branches, thoracic, acromial, and descending.
The thoracic branches, two or three in number, are distributed to the Serratiis
magnus, and Pectoral muscles, anastomosing with the intercostal branches of the
internal mammary. The acromial branches are directed outwards towards the
acromion, supplying the Deltoid muscle, and anastomosing, on the surface of the
acromiou, with the suprascapular and posterior circumflex arteries. The de-
scending branch passes in the interspace between the Pectoralis major and
Deltoid, accompanying the cephalic vein, and supplying both muscles.
The long thoracic passes downwards and inwards along the lower border of
the Pectoralis minor to the side of the chest, supplying the Serratus magnus, the
Pectoral muscles, and mammary gland, and sending branches across the axilla
to the axillary glands and Subscapularis, which anastomose with the internal
mammary and intercostal arteries.
510
ARTERIES.
Tlie thoracica alaris is a small branch, which supplies the glands and areolar
tissue of the axilla. Its place is frequently supplied by branches from some of
the other thoracic arteries.
The suhscapular^ the largest branch of the axillary artery, arises opposite the
lower border of the Subscapularis muscle, and passes downwards and backwards
along its lower margin to the inferior angle of the scapula, where it anastomoses
with the posterior scapular, a branch of the subclavian. It distributes branches
to the Subscapularis, Serratus magnus, Teres major, and Latissimus dorsi muscles,
and gives off, about an inch and a half from its origin, a large branch, the dorsalis
scapulae, which curves round the inferior border of the scapula, leaving the
axilla in the interspace between the Teres minor above, the Teres major below,
and the long head of the Triceps in front. Three branches, or sets of branches,
arise from the dorsalis scapulae : the first enters the subscapular fossa, beneath
the Subscapularis, which it supplies, anastomosing with the posterior scapular
and suprascapular arteries ; the sec-
FJg. 315. — The Surg'ical Anatomy of the
Brachial Artery.
MicscwIn-SliiriU
Ncrvi
Profu/ndA
Inferior
Profu nda
AnosfoTHotifCa
MuijiM
ond, the trunk of the artery {dorsalis
scapulee) turns round the axillary
border of the scapula, and enters the
infraspinous fossa, where it anasto-
moses with the suprascapular and
posterior scapular arteries ; and a
third, or median branch, is continued
along the axillary border of the scap-
ula, between the Teres major and
minor, and, at the dorsal surface of
the inferior angle of the bone, anasto-
moses with the posterior scapular.
The circumflex arteries wind round
the neck of the humerus. The pos-
terior circumflex (Fig. 313), the larger
of the two, arises from the back part
of the axillary opposite the lower
border of the Subscapularis muscle,
and, passing backwards with the cir-
cumflex veins and nerve through the
quadrangular space bounded by the
Teres major and minor, the scapular
head of the Triceps and the humerus
winds round the neck of that bone
and is distributed to the Deltoid
muscle and shoulder-joint, anasto-
mosing with the anterior circumflex,
suprascapular and acromial thoracic
arteries. The anterior circumflex
(Figs. 318, 314), considerably smaller
than the preceding, arises just below
that vessel, from the outer side of the
axillary artery. It passes horizon-
tally outwards, beneath the C(irae(v
b'-acliinlis and slioi't head oC tlie
Biceps, lying upon the fore part of
the neck of the liurncrus, and, on
reaching the bicijiital groove, gives
oft' an ascending branch which passes
upwards along the groove to supply
the licad of the bone and the sluml-
BRACHIAL. 511
der-joint. The trunk of tlie vessel is then continued outwards beneath the
Deltoid, which it supplies, and anastomoses with the posterior circumflex, and
acromial thoracic arteries.
Brachial Artery. (Fig. 315.)
The Brachial Artery commences at the lower margin of the tendon of the
Teres major, and, passing down the inner and anterior aspect of the arm, termi-
nates about half an inch below the bend of the elbow, where it divides into the
radial and ulnar arteries.
The direction of this vessel is marked by a line drawn from the outer side
of the axillary space between the folds of the axilla, to a point midway between
the condyles of the humerus, which corresponds to the depression along the
inner border of the Coraco-brachialis and Biceps muscles. In the upper part
of its course, the artery lies internal to the humerus ; but below, it is in front
of that bone.
Relations, This artery is superficial throughout its entire extent, being
covered, in front ^ by the integument, the superficial and deep fascia; the bicipi-
tal fascia separates it opposite the elbow from the median basilic vein ; the
median nerve crosses it at its middle ; and the basilic vein lies in the line of
the artery, but separated from it by the fascia, in the lower half of its course.
Behind^ it is separated from the inner side of the humerus above, by the long
and inner heads of the Triceps, the musculo-spiral' nerve and superior profunda
artery intervening ; and from the front of the bone below, by the insertion of
the Coraco-brachialis muscle, and by the Brachialis anticus. By its outer side^
it is in relation with the commencement of the median nerve, and the Coraco-
brachialis and Biceps muscles, which slightly overlap the artery. By its inner
side^ its upper half is in relation with the internal cutaneous and ulnar nerves,
its lower half with the median nerve. It is accompanied by two vense comites,
which lie in close contact with the artery, being connected together at intervals
by short transverse communicating branches.
Plan of the Eelatioxs of the Brachial Artery.
In Front.
Integument and fasciae.
Bicipital fascia, median basilic vein.
Median nerve.
Outer side. /^ \ Inner side.
Median nerve. ) ■Brachial \ Internal cutaneous and ulnar nerve.
Coraco-brachialis. \ Artery. j Median nerve.
Biceps.
Behind.
Triceps.
Musculo-spiral nerve.
Superior profunda artery.
Coraco-brachialis.
Brachialis anticus. s
Bend of the Elbow,
At the bend of the elbow, the brachial artery sinks deeply into a triangular
interval; the base of which is directed upwards towards the humerus, and the
sides of which are bounded, externally, by the Supinator longus; internally, by
the Pronator radii teres; its floor is formed by the Brachialis anticus and
Supinator brevis. This space contains the brachial artery, with its accom-
panying veins; the radial and ulnar arteries; the median and musculo-spiral
nerves; and the tendon of the Biceps. The brachial artery occupies the middle
line of this space, and divides opposite the coronoid process of the ulna into the
512 ARTERIES.
radial and ulnar arteries ; it is covered, in front^ by the integument, tlie super-
ficial fascia, and tlie median basilic vein, the vein being separated from direct
contact with the artery by the bicipital fascia. Behind^ it lies on the Brachialis
anticus, which separates it from the elbow-joint. The median nerve lies on the
inner side of the artery, but separated from it below by an interval of half an
inch. The tendon of the Biceps lies to the outer side of the space, and the
musculo-spiral nerve still more externally lying upon the Supinator brevis, and
partly concealed by the Supinator longus.
Peculiarities of tlie Artery as regards its Course. The brachial artery, accompanied by the
median nerve, may leave the inner border of the Biceps, and descend towards the inner condyle
of the humerus, where it usually curves round a prominence of bone, to vrhich it is connected by
a fibrous band; it then inclines outwards, beneath or through the substance of the Pronator teres
muscle, to the bend of the elbow. The variation bears considerable analogy with the normal
condition of the artery in some of the caruivora ; it has been referred to, above, in the description
of the humerus.
^6 regards its Division. Occasionally, the artery is divided for a short distance at its upper
part into two trunks, which are united above and below. A similar peculiarity occurs in the
main vessel of the lower limb.
The point of bifurcation may be above or below the usual point, the former condition being by
far the most frequent. Out of 481 examinations recorded by Mr. Quain, some made on the right,
and some on the left side of the body, in 386 the artery bifurcated in its normal position. In one
case only was the place of division lower than usual, being two or three inches below the elbow-
joint. " In 94 cases out of 481, or about one in 5^, there were two arteries instead of one in some
part, or in the whole of the arm."
There appears, however, to be no correspondence between the arteries of the two arms, with
respect to their irregular division ; for in sixty-one bodies it occurred on one side only in forty-
three ; on both sides, in different positions, in thirteen : on .both sides, in the same position, in five.
The point of bifurcation takes place at different parts of the arm, being most frequent in the
upper part, less so in the lower part, and least .so in the middle, the most usual point for the
application of a ligature ; under any of these circumstances, two large arteries would be found
in the arm instead of one. The most frequent (in three out of four) of these peculiarities is the
high division of the radial. That artery often arises from the inner side of the brachial, and runs
parallel with the main trunk to the elbow, where it crosses it, lying beneath the fascia; or it may
perforate the fascia, and pass over the artery immediately beneath the integument.
The ulnar sometimes arises from the brachial high up, and then occasionally leaves that vessel
at the lower part of the arm, and descends towards the inner condyle. In the forearm, it generally
lies beneath the deep fascia, superficial to the Flexor muscles ; occasionally between the integu-
ment and deep fascia, and very rarely beneath the Flexor muscles.
1'he interosseous artery sometimes arises from the upper part of the brachial or axillary : as it
passes down the arm, it lies behind the main trunk, and, at the bend of the elbow, regains its
usual position.
In some cases of high division of the radial, the remaining trunk (ulnar-interosseous) occasionally
passes, together with the median nerve, along the inner margin of the arm to the inner condyle,
and then passing from within outwards, beneath or through the Pronator teres, regains its usual
position at the bend of the elbow.
Occasionally, the two arteries representing the brachial are connected at the bend of the elbow
by a short transverse branch, and are even sometimes reunited.
Sometimes, long slender vessels, vasa aherrantia, connect the brachial or axillary arteries with
one of the arteries of the forearm, or a branch from them. These vessels usually join the radial.
Varieties in Muscular Relations.^ The brachial artery is occasionally concealed, in some part
of its course, by muscular or tendinous slips derived from various sources. In the upper third
of the arm, the brachial vessels and median nerve have been seen concealed, to the extent of three
inches, by a muscular layer of considerable thickness, derived from the (.'oraco-brachialis, which
passed round to the iimer side of the vessel, and joined the internal head of the 'I'riceps. In the
lower half of the arm the artery is occasionally concealed by a broad thin head to the I5iceps
muscle. A narrow fleshy slip from the Biceps has been seen to cross the artery, concealing it for
an inch and a half, its tendon ending in the aponeurosis covering the Pronator teres. A muscular
and tendinous slip has been seen to arise from the external bicipital ridge l)y a long tendon, cross
oblifincly behind the; long tendon of the Biceps, and end in a fleshy hflly, which api)ears on the
inner side of ihe arm between the Biceps and (/oraco brachialis, passes down along the iniu>r edge
of the former, and crosses the artery very oblifpiely. so as to lie in front of it for three inches,
and, finally, gives rise to a narrow flattened tendon, which is inserted into the aponeurosis over
the I'ronator teres. A tendinous slip, arising from the deep part of the tendon of the Pecloralis
major, has been seen to cross the artery obliquely at or below the Coraco-brachialis, and join
the intermiiscidar septum above the inner condyle. The Brachialis anticus not unfretpienlly
' Sec Stj{UThici;s"s Anatomical and Pliijsiological OI)scrvalions.
SURGICAL ANATOMY OF BRACHIAL ARTERY. 513
projects at the outer side of tlie artery, and occasionally overlaps it, sending inwards, across the
artery, an aponeurosis which binds the vessel down upon the Brachialis anticus. Sometimes, a
fleshy slip from the muscle covers the vessel, in one case to the extent of three inches. In some
cases of high origin of the Pronator teres, an aponeurosis extends from it to join the Brachialis
anticus external to the artery; a kind of arch being thus formed under which the principal artery
and median nerve pass, so as to be concealed for half an inch above the transverse level of the
condyle.
SurgiralAnatomy. Compression of the brachial artery is required in cases of amputation and
some other operations in the arm and forearm; and it will be observed, that it may be effected
in almost any part of the course of the artery. If pressure is made in the upper part of the limb,
it should be directed from within outwards, and if in the lower part, from before backwards, as
the artery lies on the inner side of the humerus above, and in front of it below. The most
favorable situation is near the insertion of the Coraco brachialis.
'I'he application of a ligature to the brachial artery may be required in cases of wounds of the
vessel, and in some cases of wound of the palmar arch. It is also sometimes necessary in cases
of aneurism of the brachial, the radial, ulnar, or interosseous arteries. The artery may be secured
in any part of its course. The chief guides in determining its position are the surface-markings
produced by the inner margin of the Coraco-brachialis and Biceps, the known course of the vessel,
and its pulsation, which sliould be carefully felt for before any operation is performed, as the
vessel occasionally deviates from its usual position in the arm. In whatever situation the opera-
tion is performed, great care is necessary, on account of the extreme thinness of the parts covering
the artery, and the intimate connection which the vessel has throughout its whole course with
important nerves and veins. Sometimes a thin layer of muscular fibre is met with concealing
the artery ; if such is the case, it must be cut across in order to expose the vessel.
In the tipper third of the arm the artery may be exposed in the following manner: The
patient being placed horizontally upon a table, the affected limb should be raised from the side,
and the hand supinated. An incision about two inches in length should be made on the ulnar
side of the Coraco-brachialis muscle, and the subjacent fixscia cautiously divided, so as to avoid
wounding the internal cutaneous nerve or basilic vein, which sometimes run on the surface of the
artery as high as the axilla. The fascia having been divided, it should be remembered, that the
ulnar and internal cutaneous nerves lie on the inner side of the artery, the median on the outer
side, the latter nerve being occasionally superficial to the artery in this situation, and that the
venae comites are also in relation with the vessel, one on either side. These being carefully
separated, the aneurism needle should be passed round the artery from the ulnar to the radial side.
If two arteries are present in the arm, in consequence of a high division, they are usually
placed side by side; and if they are exposed in an operation, the surgeon should endeavor to
ascertain, by alternately pressing on each vessel, which of the two communicates with the wound
or aneurism, when a ligature may be applied accordingly ; or if pulsation or hemorrhage ceases
only when both vessels are compressed, both vessels may be tied, as it may be concluded that the
two communicate above the seat of disease, or are reunited.
It should also be remembered, that two arteries may be present in the arm in a case of high
division, and that one of these may be found along the inner intermuscular septum, in a line
towards the inner condyle of the humerus, or in the usual position of the brachial, but deeply
placed beneath the common trunk : a knowledge of these facts will suggest the precautions
necessary in every case, and indicate the measures to be adopted when anomalies are met with.
Li the middle of the arm the brachial artery may be exposed by making an incision along
the inner margin of the Biceps muscle. The forearm being bent so as to relax the muscle, it
should be drawn slightly aside, and, the fascia being carefully divided, the median nerve will be
exposed lying upon the artery (sometimes beneath) ; this being drawn inwards and the muscle
outwards, the artery should be separated from its accompanying veins and secured. In this situa-
tion the inferior profunda may be mistaken for the main trunk, especially if enlarged, from the
collateral circulation having become established ; this may be avoided by directing the incision
externally towards the Biceps rather than inwards or backwards towards the Triceps.
The lower part of the brachial artery/ is of extreme interest in a surgical point of view, on
account of the relation which it bears to the veins most commonly opened in venesection. Of
these vessels, the median basilic is the largest and most prominent, and, consequently, the one
usually selected for the opei-ation. It should be remembered, that this vein runs parallel with
the brachial artery, from which it is separated by the bicipital fascia, and that in no case should
this vessel be selected for venesection, except in a part which is not in contact with the artery.
Collateral Circulation. After the application of a ligature to the brachial artery in the upper
third of the arm, the circulation is carried on by branches from the circumflex and subscapular
arteries, anastomosing with ascending branches from the superior profunda. If the brachial is
tied beloiv the origin of the pi'ofunda arteries, the circulation is maintained by the branches of the
profunda;, anastomosing with the recurrent radial, ulnar, and interosseous arteries. In two cases
described by Mr. South,' in which the brachial artery had been tied some time previously, in one
' Chelius' Surgery, vol. ii. p. 254. See also White's engraving referred to by Mr. South, of
the anastomosing branches after ligature of the brachial, in White's Crt.se.s in Surgery. Porta
also gives a case (with drawings) of the circulation after ligature of both brachial and radial. —
Alter azioni Patologiche delle Arterie.
33
514 ARTERIES.
" a lon<? portion of the artery had been oWiterated, and sets of vessels are descendin<T on either
side from above the obliteration, to be received into others which ascend in a similar manner
from below it. In the other, the obliteration is less extensive, and a single curved artery about
as big as a crow-quill passes from the upper to the lower open part of the artery."
The brandies of tlie bracliial artery are the
Superior profunda. Inferior profunda.
Nutrient artery. Anastoniotica magna.
Muscular.
The siqoerior profunda arises from the inner and back part of the brachial,
opposite the lower border of the Teres major, and passes backwards to the
interval between the outer and inner heads of the Triceps muscle, accompanied
by the musculo-spiral nerve ; it winds round the back part of the shaft of the
humerus in the spiral groove, between the Triceps and the bone, and descends
on the outer side of the arm to the space between the Brachialis anticus and
Sitpinator longus as far as the elbow, where it anastomoses with the recurrent
branch of the radial artery. It supplies the Deltoid, Coraco-brachialis, and
Triceps muscles, and whilst in the groove between the Triceps and the bone, it
gives off the posterior articular artery, which descends perpendicularly between
the Triceps and the bone, to the back part of the elbow-joint, where it anasto-
moses with the interosseous recurrent branch, and, on the inner side of the arm,
with the posterior ulnar recurrent, and with the anastomotica magna or inferior
profunda (Fig. 318). ■
The nutrient artery of the shaft of the humerus arises from the brachial, about
the middle of the arm. Passing downwards, it enters the nutrient canal of that
bone, near the insertion of the Coraco-brachialis muscle.
The inferior profunda^ of small size, arises from the brachial, a little below
the middle of the arm ; piercing the internal intermuscular septum, it descends
on the surface of the inner head of the Triceps muscle, to the space between
the inner condyle and olecranon, accompanied by the ulnar nerve, and termi-
nates by anastomosing with the posterior ulnar recurrent, and anastomotica
magna. It also su]3plies a branch to the front of the internal condyle, which
anastomoses with the anterior ulnar recurrent.
The anastomotica magna arises from the brachial, about two inches above the
elbow-joint. It passes transversely inwards upon the Brachialis anticus, and,
piercing the internal intermuscular septum, winds round the back part of the
humerus between the Triceps and the bone, forming anarch above the olecranon
fossa, by its junction with the posterior articular branch of the superior pro-
funda. As this vessel lies on the Brachialis anticus, an offset passes between
the internal condyle and olecranon, which anastomoses with the inferior pro-
funda and posterior ulnar recurrent arteries. Other branches ascend to join the
inferior profunda ; and some descend in front of the inner condyle, to anasto-
mose with the anterior ulnar recurrent.
The muscular are three or four large branches, which are distributed to the
muscles in the course of the artery. They supply the Coraco-brachialis, Biceps,
and Brachialis anticus muscles.
The Anastomosis around the Elhow-joint (Fig. 818). The vessels engaged in
this anastomosis may be conveniently divided into those situated in front of and
behind the Internal and External Condyles. The branches anastomosing in front
of the Internal Condyle are : The anastomotica magna, the anterior ulnar re-
current, and the anterior terminal branch of the inferior profunda. Those behind
the Internal Condyle are: The anastomotica magna, the posterior ulnar recur-
rent, and the posterior terminal brancli of the inferior profunda. Tlie branches
anastomosing 'm/ror?i of the External Condyle are: The radial recurrent and
tlic termination of the superior profunda. Those behind the External Condyle
(perhaps more properly described as being situated between the external con-
dyle and the olecranon) arc : The anastomotica magna, the interosseous recur-
rent, and the posterior articular branch of the superior profunda. There is also
RADIAL. 515
11 large arch, of anastomosis above tlie olecranon formed by tlie interosseous
recurrent, joining with the anastomotica magna and posterior ulnar recurrent
(Fig. 318).
From this description it will be observed that the anastomotica magna is the
vessel most engaged, the only part of the anastomosis in which it is not employed
being that in front of the external condyle.
Eadial Artery.
The Eadial Artery appears, from its direction, to be the continuation of the
brachial, but, in size, it is smaller than the ulnar. It commences at the bifurca-
tion of the brachial, just below the bend of the elbow, and passes along the
radial side of the forearm to the wrist ; it then winds backwards, round the
outer side of the carpus, beneath the extensor tendons of the thumb, and,
finally, passes forwards between the two heads of the first Dorsal interosseous
muscle, into the palm of the hand, where it crosses the metacarpal bones to the
ulnar border of the hand, to form the deep palmar arch. At its termination, it
inosculates with the deep branch of the ulnar artery. The relations of this
vessel may thus be conveniently divided into three parts, viz., in the forearm,
at the back of the wrist, and in the hand.
Relations. In the forearm,^ this vessel extends from opposite the neck of the
radius, to the fore part of the styloid process, being placed to the inner side of
the shaft of the bone above, and in front of it below. It is superficial through-
out its entire extent, being covered by the integument, the superficial and deep
fascia, and slightly overlapped above by the Supinator longus. In its course
downwards, it lies upon the tendon of the Biceps, the Su]3inator brevis, the Pro-
nator radii teres, the radial origin of the Flexor sublimis digitorum, the Flexor
longus pollicis, the Pronator quadratus, and the lower extremity of the radius.
In the upper third of its course, it lies between the Supinator longus and the
Pronator radii teres ; in its lower two-thirds, between the tendons of the Supi-
nator longus and the Flexor carpi radialis. The radial nerve lies along the outer
side of the artery in the middle third of its course ; and some filaments of the
musculo-cutaneous nerve, after piercing the deep fascia, run along the lower
part of the artery as it winds round the wrist. The vessel is accompanied by
ven£e comites throughout its whole course.
Plan of the Eelations of the Eadial Artery iisr the Forearm.
In front.
Integument — superficial and deep fasciss.
Supinator lougns.
Inner side. I -r, a- ^ \ Outer side.
/ Radial \
Pronator radii teres. ( Artery in I Supinator longus.
Flexor carpi radialis. \ Forearm. / Eadial nerve (middle third).
Behind.
Tendon of Biceps.
Supinator brevis.
Pronator radii teres.
Flexor sublimis digitorum.
Flexor longus pollicis.
Pronator quadratus.
Radius.
At the wrist, as it winds round the outer side of the carpus, from the styloid
process to the first interosseous space, it lies upon the external lateral ligament,
516
ARTERIES.
Ulnar Arteries.
being covered by tbe extensor tendons of the tliiimb, subcutaneous veins, some
filaments of tlie radial nerve, and the integument. It is accompanied by two
veins and a filament of the
Fig. 316.— Tlie Surgical Anatomy of the Radial and musculo-CUtaneous nerve.
In the hand^ it passes from
the upper end of the first inter-
osseous space, between the
heads of the Abductor indicis
or first Dorsal interosseous
muscle transversely across the
palm, to the base of the meta- .
carpal bone of the little finger,
where it inosculates with the
communicating branch from
the ulnar artery, forming the
deep palmar arch. It lies
upon the carpal extremities
of the metacarpal bones and
the Interossei muscles, being
covered by the flexor tendons
of the fingers, the Lumbri-
cales, the muscles of the little
finger, and the Flexor brevis
poUicis, and is accompanied
by the deep branch of the
ulnar nerve.
Peculiarities. The origin of the
radial artery varies in the propor-
tion nearly of one in eight cases. In
one case the origin was lower than
usual. In the other cases, the upper
part of the brachial was a more fre-
quent source of origin than the axil-
lary. The variations in the position
of this vessel in the arm, and at the
bend of the elbow, have been already
mentioned. In the forearm it devi-
ates less frequently from its position
than the ulnar. It has been found
lying over the fascia, instead of be-
neath it. It has also been observed
on the surface oF the Supinator lon-
gns instead of along its inner border :
and in turning round the wrist, it
has been seen lying over, instead of
beneath, the E.xtensor tendons.
Surgical Anatomy. 'I'hc opera-
tion of tying the radial artery is re-
quired in cases of wounds either of
its trunk, or in some of its branches,
or for aneurism : and it will be ob-
served, that the vessel may be ex-
posed in any part of its course
through the forearm without the
division of any muscular fibres. 'I'he
operation in the middle or inferior
third of the forearm is easily jier-
fornied ; but in the upper third near
the elliow, it is attended with some
dilTicully, from the greater depth of
the vessel, and from its being over-
la[)ped by the Supinator longus and
Pronator teres muscles.
Superficial I
Imiiic/i cf UZnitr
BRANCHES OF RADIAL. 517
To tie the artery in tlie upper third, an incision three inches in length should be made through
the integument, from the bend of the elbow obliquely downwards and outwards, on the radial
side of the forearm, avoiding the branches of the median vein ; the fascia of the arm being divided
and the Supinator longus drawn a little outwards, the arlery will be exposed. The veuas com-
ites should be carefully separated from the vessel, and the ligature passed from the radial to
the ulnar side.
In the middle third of the forearm the artery may be exposed by making an incision of similar
length on the inner margin of the Supinator longus. In this situation, the radial nerve lies in
close relation with the outer side of the artery, and should as well as the veins be carefully
avoided.
In the lower third, the artery is easily secured by dividing the integument and fasciae in the
interval between the tendons of the Supinator longus and Flexor carpi radialis muscles.
The brandies of tlie radial artery may be divided into three groups corre-
sponding witb the three regions in which the vessel is situated.
r Eadial recurrent. f Posterior carpal.
In the J Muscular. W ' t \ ^^tacarpal.
Forearm. \ Superficialis volse. " } Dorsales pollicis.
y Anterior carpal. 1^ Dorsalis indicis.
r Princeps pollicis.
j Eadialis indicis.
Perforating.
Interosseous.
Hand.
The radial recurrent is given off immediately below the elbow. It ascends
between the branches of the musculo-spiral nerve, lying on the Supinator brevis
and then between the Supinator longus and Brachialis anticus, supplying these
muscles and the elbow-joint, and anastomosing with the terminal branches of
the superior profunda.
The muscular hranches are distributed to the muscles on the radial side of the
forearm.
The superficialis volse arises from the radial artery, just where this vessel is
about to wind round the wrist. Punning forwards, it passes between the mus-
cles of the thumb, which it supplies, and sometimes anastomoses with the termi-
nation of the ulnar artery, completing the superficial palmar arch. This vessel
varies considerably in size ; usually it is very small, and terminates in the mus-
cles of the thumb ; sometimes it is as large as the continuation of the radial.
The carpal hranches supply the joints of the wrist. The anterior carpal is a
small vessel which arises from the radial artery near the lower border of the
Pronator quadrat us, and, running inwards in front of the radius, anastomoses
with the anterior carpal branch of the ulnar artery. From the arch thus formed,
branches descend to supply the articulations of the wrist.
The posterior ca,rpal is a small vessel which arises from the radial artery
beneath the extensor tendons of the thumb ; crossing the carpus transversely to
the inner border of the hand, it anastomoses with the posterior carpal branch
of the ulnar. It sends branches upwards, which anastomose with the termina-
tion of the anterior interosseous artery; other branches descend to the meta-
carpal spaces ; they are the dorsal interosseous arteries for the third and fourth
interosseous spaces ; they anastomose with the posterior perforating branches from
the deep palmar arch.
The metacarpal {first dorsal interosseous branch) arises beneath the extensor
tendons of the thumb, sometimes with the posterior carpal artery ; running for-
wards on the second dorsal interosseous muscle, it communicates, behind, with
the corresponding perforating branch of the deep palmar arch; and, in front,
inosculates with the digital branch of the superficial palmar arch, and supplies
the adjoining sides of the index and middle fingers.
The dorsales pollicis are two small vessels which run along the side of the
dorsal aspect of the thumb. Thej^ arise separately or occasionally by a common
trunk near the base of the first metacarpal bone.
518
ARTERIES.
Fig. 317. — Ulnar and Radial Arteries.
Deep View.
Vlnnf
He eu I rent
Deep Liujich »/ TTlr.ar
The dor sails indicis^ also a small
branch, runs along the radial side of
the back of the index finger, sending
a few branches to the Abductor in-
dicis.
The princeps pollicis arises from
the radial just as it turns inwards to
the deep part of the hand ; it de-
scends between the Abductor in-
dicis and Abductor pollicis, along
the ulnar side of the metacarpal
bone of the thumb, to the base of
the first phalanx, where it divides
into two branches, which run along
the sides of the palmar aspect of the
thumb, and form an arch on the
under surface of the last phalanx,
from which branches are distributed
to the integument and cellular mem-
brane of the thumb.
The radialis indicis arises close to
the preceding, descends between the
Abductor indicis and Adductor pol-
licis, and runs along the radial side
of the index finger to its extremity,
where it anastomoses with the col-
lateral digital artery from the super-
ficial palmar arch. At the lower
border of the Adductor pollicis, this
vessel anastomoses with the prin-
ceps pollicis, and gives a communi-
cating branch to the superficial
palmar arch.
The perforating arteries,' three in
number, pass backwards between the
heads of the last three Dorsal inter-
ossei muscles, to inosculate with the
dorsal interosseous arteries.
The pahnar interosseous^ three or
four in number, are branches of the
deep palmar arch ; they run forwards
upon the Interossei muscles, and
anastomose at the clefts of the fingers
with the digital branches of the
superficial arch.
Ulnae Artery.
The Ulnar Artery, the larger of the two subdivisions of the brachial, com-
mences a little below the bend of the elbow, and crosses the inner side of the
forearm obliquely inwards, to the commencement of its lower half; it then runs
along its ulnar border to the wrist, crosses the annular ligament on the radial
side of the pisiform bone, and passes across the ])aliii of the hand, forming the
superficial ])alniar arch, which sometimes terminates by inosculating Avith the
superficialis voire.
Relations in the Forearra. In its tipper hxilf^ it is dce])ly seated, being covered
by all the superficial Flex(jr muscles, excepting the Flexor carpi ulnaris ; it is
ULNAE. 519
crossed by tlie median nerve, wliicli lies to its inner side for about an inch, and
it lies upon the Bracliialis anticus and Flexor profundus digitoruni muscles. In
the lower half of the forearm, it lies upon the Flexor profundus, being covered
by the integument, the superficial and deep fascia, and is placed between the
Flexor carpi ulnaris and Flexor sublimis digitorum muscles. It is accompanied
by two venae comites ; the ulnar nerve lies on its inner side for the lower two-
thirds of its extent, and a small branch from the nerve descends on the lower
part of the vessel to the palm of the hand.
Flax of Eelatioxs of the Ulnar Aetery in the Forearm.
In front.
Superficial layer of flexor muscles. ) jj . j^g^jf
Median nerve. j I F
Superficial and deep fasciaj. Lower half.
Inner side. f tti„, \ Older side.
F exor carpi ulnaris. ^ V) Flexor sublimis diffitorum.
I X .1 • 1 N \ Forearm. / o
Uluar nerve (lower two-thiras).
Behin d.
Brachialis anticus.
Flexor profundus digitorum.
At the wrist (Fig. 316), the ulnar artery is covered by the integument and
fascia and lies upon the anterior annular ligament. On its inner side is the
pisiform bone. The ulnar nerve lies at the inner side, and somewhat behind
the artery.
In the palm of the hand., the continuation of the ulnar artery is called the
superficial palmar arch; it passes obliquely outwards to the interspace between
the ball of the thumb and the index finger, where it occasionally anastomoses
with the superficialis voice, and a branch from the radialis indicis, thus com-
pleting the arch. The convexity of this arch is directed towards the fingers, its
concavity towards the muscles of the thumb. If the thumb be put at right
angles to the hand, the position of the superficial palmar arch will be roughly
indicated by a line drawn along the lower margin of the thumb across the palm
of the hand : the deep palmar arch is situated about a finger's breadth nearer
to the carpus.
The superficial palmar arch is covered by the Palmaris brevis, the palmar
fascia, and integument ; and lies upon the annular ligament, the muscles of the
little finger, the tendons of the superficial flexor, and the divisions of the median
and ulnar nerves, the latter accompanying the artery a short part of its course.
Eelations of the Superficial Palmar Arch.
Behind.
In front. /"^ ^^\ Annular ligament.
Inteo'ument / Ulnar \ Origin of muscles of little finger.
Pal maris brevis. I "^Hai^d'" Superficial flexor tendons.
Palmar fascia. \ ' / Division of median and ulnar
\^^ / nerves.
Pecidiarities. The ulnar artery has been found to vary in its origin nearly in the proportion
of one in thirteen cases, in one case arising lower than usual, about two or three inches below the
elbow, and in all the other cases much higher, the brachial being a more frequent source of origin
than the axillary.
Variations in the position of this vessel are more frequent than in the radial. When its origin
is normal the course of the vessel is rarely changed. When it arises high up. it is almost invari-
ably superficial to the Flexor muscles in the forearm, lying commonly beneath the fascia, more
520 ARTERIES.
rarely between the fascia and integument. In a few cases, its position was subcutaneous in the
upper part of the forearm, subaponeurotic in the lower part.
Surgical Anatomy. The application of a ligature to this vessel is required in cases of wound
of the artery, or of its branches, or in consequence of aneurism. In the upper half of the forearm,
the artery is deeply seated beneath the superficial Flexor muscles, and their division would be
requisite in a case of recent wound of the artery in this situation, in order to secure it, but under
no other circumstances. In the middle and lower third of the forearm, this vessel may be easily
secured by making an incision on the radial side of the tendon of the Flexor carpi ulnaris : the
deep fascia being divided, and the Flexor carpi ulnaris and its companion muscle, the Flexor
sublimis, being separated from each other, the vessel will be exposed, accompanied by its venai
comitcs. the ulnar nerve lying on its inner side. The veins being separated from the artery, the
ligature should be passed from the ulnar to the radial side, taking care to avoid the ulnar nerve.
The brandies of the ulnar artery may be arranged in the following groups : —
[ Anterior ulnar recurrent.
I Posterior ulnar recurrent.
Forearm. -{ ^ . ( Anterior interosseous,
interosseous { -n . •
[ rosterior interosseous.
^ Muscular.
-U7 : f \ Anterior carpal.
■ I Posterior carpal.
TT 7 j Deep or communicating branch.
nana. | j)-g^^^p
The anterior ulnar recurrent (Fig. 317) arises immediately below the elbow-
joint, passes upwards and inwards between the Brachialis anticus and Pronator
radii teres, supplies those muscles, and, in front of the inner condyle, anastomoses
with the anastomotica magna and inferior profunda.
The posterior ulnar recurrent is much larger, and arises somewhat lower than
the preceding. It passes backwards and inwards, beneath the Flexor sublimis,
and ascends behind the inner condyle of the humerus. In the interval between
this process and the olecranon, it lies beneath the Flexor carpi ulnaris, ascending
between the heads of that muscle, beneath the ulnar nerve ; it supplies the
neighboring muscles and joint, and anastomoses with the inferior profunda,
anastomotica magna, and interosseous recurrent arteries (Fig. 318).
The interosseous artery (Fig. 317) is a short trunk, about an inch in length, and
of considerable size, which arises immediately below the tuberosity of the radius,
and, passing backwards to the upper border of the interosseous membrane,
divides into two branches, the anterior and posterior interosseous.
The anterior interosseous passes down the forearm on the anterior surface of
the interosseous membrane, to which it is connected by a thin aponeurotic arch.
It is accompanied by the interosseous branch of the median nerve, and over-
lapped by the contiguous margins of the Flexor profundus digitorum and Flexor
longus pollicis muscles, giving off in this situation muscular branches, and the
nutrient arteries of the radius and ulna. At the upper border of the Pronator
quadratus, a branch descends in front of that muscle, to anastomose in front of
the carpus with branches from the anterior carpal and deep palmar arch. The
continuation of the artery passes behind the Pronator quadratus (Kig. 318), and,
piercing the interosseous membrane, descends to the back of the wrist, where it
anastomoses with the posterior interosseous and the posterior carpal branches of
the radial and ulnar arteries. The anterior interosseous gives off a long, slender
branch, which accompanies the median nerve, and gives offsets to its substance.
This, the median artery, is sometimes much enlarged.
The posterior interosseous artery passes backwards through the interval between
the oblif^uc ligament and the upper border of the interosseous mend)rane, and
runs down the back part of the forearm, between the sniierficial and deep layer
of jnusclcs, to both of which it distributes branches. Descending to the back
of tlie wrist, it anastomoses with the termination of the anterior interosseous,
and with the posterior carpal branches of the radial and nlnnr arteries. This
artery gives off, near its origin, the interosseous recurrent branch, a large vessel,
BRANCHES OF ULNAR.
521
Fig:. 318. — Arteries of the Back of the Forearm and Haud.
9 1 Vesoentfirrtf Brnnr/t f-on
1 Su.j,.ri^rrTof^,.da,
Tiixter.
irMeeur
fnfei-nsxfoaa
wliicli ascends to the interval
between tke external condyle
and olecranon, beneath, tlie An-
coneus and Supinator brevis,
anastomosing witli a branch
from the superior profunda,
and with the posterior ulnar
recurrent, and anastomotica
magna.
The muscular hranches are
distributed to the muscles along
the ulnar side of the forearm.
The carpal hranches are in-
tended for the supply of the
wrist-joint.
The anterior carpal is a small
vessel which crosses the front
of the carpus beneath the ten-
dons of the Flexor profundus,
and inosculates with a corre-
sponding branch of the radial
artery.
The posterior carpal arises
immediately above the pisiform
bone, winding backwards be-
neath the tendon of the Flexor
carpi ulnaris; it gives off' a
branch which passes across the
dorsal surface of the carpus
beneath the extensor tendons,
anastomosing with a corre-
sponding branch of the radial
artery, and forming the poste-
rior carpal arch ; it is then con-
tinued along the metacarpal
bone of the little finger, form-
ing its dorsal branch.
The deep or covimunicating
hranch (Fig. 317) arises at the
commencement of the palmar
arch, and passes deeply inwards
between the Abductor minimi
digiti and Flexor brevis minimi
digiti, near their origins; it
anastomoses with the termi-
nation of the radial artery,
completing the deep palmar
arch.
The digital hranches (Fig.
316), four in number, are given off from the convexity of the superficial palmar
arch.^ They supply the ulnar side of the little finger, and the adjoining sides of
the little, ring, middle, and index fingers; the radial side of the index finger
and thumb being supplied from the radial artery. The digital arteries at first
lie superficial to the flexor tendons, but as ihej "pass forwards with the digital
nerves to the clefts between the fingers, they lie between them, and are there
joined by the interosseous branches from the deep palmar arch. The digital
arteries on the sides of the fingers lie beneath the digital nerves ; and, about
522 ARTERIES.
tlie middle of the last plialanx, tlie two brandies for each, finger form an arcli,
from the convexity of which branches pass to supply the matrix of the nail.
The Desceitding Aoeta.
The Descending Aorta is divided into two portions, the thoracic, and abdomi-
nal, in correspondence with the two great cavities of the trunk in which it is
situated.
The Thoracic Aorta.
The Thoracic Aorta commences at the lower border of the fourth dorsal ver-
tebra, on the left side, and terminates at the aortic opening in the Diaphragm,
in front of the last dorsal vertebra. At its commencement, it is situated on the
left side of the spine ; it approaches the median line as it descends ; and, at its
termination, lies directly in front of the column. The direction of this vessel
being influenced by the spine, upon which it rests, it describes a curve which is
concave forwards in the dorsal region. As the branches given off from it are
small, the diminution in the size of the vessel is inconsiderable. It is contained
in the back part of the posterior mediastinum, being in relation, in front ^ from
above downwards, with the left pulmonary artery, the left bronchus, the peri-
cardium, and the oesophagus ; hehind^ with the vertebral column, and the vena
azygos minor; on the right side^ with the vena azygos major, and thoracic duct;
on the left side, with the left pleura and lung. The oesophagus, with its accom-
panying nerves, lies on the right side of the aorta above : in front of the artery,
in the middle of its course ; whilst, at its loiver part, it is on the left side, on a ,
plane anterior to it.
Plan of the Eelations of the Thoracic Aorta.
In front.
Left pulmonary artery.
Left Ijroncbus.
Pericardium.
(Esophagus.
Right side. / \ Left side.
CEsophagus (above). / Thoracic I Pleura.
Vena azygos major. I Aorta. ) Left lung.
'I'lioracic duct. \ / CEsophagus (below).
Behind.
Vertebral column.
Vena azygos minor.
Siirqical Anatomy. The student should now consider the effects likely to be produced by
nneurism of the thoracic aorta, a disease of common occurrence. When we consider the great
depth of the vessel from the surface, and the number of important structures which surround it
on every side, it may be easily conceived what a variety of obscure symiitoms may arise from
disease of this part of the arterial system, and how they may be liable to be mistaken for those,
of other affections. Aneurism of the Ihoracic aorta most usually extends backwards, along Ihe
left side of the spine, producing absorption of the bodies of the vertebraj, with curvature of the
Kl)ine; whilst the irritation or pressure on the cord will give rise to pain, eithc>r iu the chest, back,
or loins, with radiating pain in the left upper intercostal spaces, from pressure on the intercostal
nerves ; at the same time the tumor mny project ba,ckwards on each side of the spine, beneath the
integument, as a pulsating swelling, siu'iulatnig abscess connected with diseased bone ; or it may
displace the fcsophiigus. and comjiress the lung on one or the other side. ' If the tumor extend
forward, it may press upon and displace the heart, giving rise to pali)itation and other symptoms
of disease of that organ ; or it may displace, or even compress, the (vsophagus, causing i)ain and
difficulty of swallowing, as in stricture of that tube, and ultimately even open into it by ulcera-
tion, producing fatal hemorrhage. If the disease make way to either side, it may press upon the
thoracic duct ; or it may burst into the pleural cavity, or into the trachea or hing ; and lastly, it
may open into the posterior mediastinum.
BRANCHES OF THE THORACIC AORTA. 523
The aorta is, comparatively often, found to be obliterated at a particular spot, viz., at the
junction of the arch with the thoracic aorta, just below the ductus arteriosus. Whether this is
the result of disease, or of congenital malformation, is immaterial to our present purpose; it
affords an interesting opportunity of observing the resources of the collateral circulation. The
course of the anastomosing vessels, by which the blood is brought from the upper to the lower
part of the artery, will be found well described in an account of two cases in the Pathological
Transactions, vols. viii. and x. In the former (p. 162), Mr. Sydney Jones thus suras up the
detailed description of the anastomosing vessels. " The principal communications by which the
circulation was carried on, were — Firstly, the internal mammary, anastomosing with the inter-
costal arteries, with the phrenic of the abdominal aorta by means of the musculo-phrenic and
comes nervi phrenici, and largely with the deep epigastric. Secondly, the superior intercostal,
anastomosing anteriorly by means of a large branch with the first aortic intercostal, and pos-
teriorly with the posterior branch of the same artery. Thirdly, the inferior thyroid, by means of
a branch about the size of an ordinary radial, formed a communication with the first aortic inter-
costal. Fourthly, the transversalis colli, by means of very large communications with the posterior
branches of the iiitercostals. Fifthly, the branches (of the subclavian and axillary) going to the
side of the chest were large and anastomosed freely with the lateral branches of the intercostals."
In the second case also (vol. x. p. 97), Mr. Wood describes the anastomoses in a somewhat similar
manner, adding the remark, that " the blood which was brought into the aorta through the anas-
tomoses of the intercostal arteries, appeared to be expended principally in supplying the abdomen
and pelvis; while the supply to the lower extremities had passed through the internal mammary
and epigastrics."
Branches of the Thoracic Aorta.
Pericardiac. CEsopliageal.
Broncliial. Posterior mediastinal.
Intercostal.
Tlie pericardiac are a few small vessels, irregular in tlieir origin, distributed
to the pericardium.
The bronchial arteries are the nutrient vessels of the lungs, and vary in
number, size, and origin. That of the right side arises from the first aortic
intercostal, or by a common trunk with the left bronchial, from the front of the
thoracic aorta. Those of the left side, usually two in number, arise from the
thoracic aorta, one a little lower than the other. Each vessel is directed to the
back part of the corresponding bronchus, along Avhich they run, dividing and
subdividing upon the bronchial tubes, supplying them, the cellular tissue of
the lungs, the bronchial glands, and the oesophagus.
The oesophageal arteries^ usually four or five in number, arise from the front
of the aorta, and pass obliquely downwards to the ossophagus, forming a chain
of anastomoses along that tube anastomosing with the oesophageal branches of
the inferior thyroid arteries above, and with ascending branches from the
phrenic and gastric arteries below.
The posterior mediastinal arteries are numerous small vessels which supply
the glands and loose areolar tissue in the mediastinum.
The Intercostal arteries arise from the back part of the aorta. They are
usually ten in number on each side, the superior intercostal space {and occasion-
ally the second one) being supplied by the superior intercostal, a branch of the
subclavian. The right intercostals are longer than the left, on account of the
position of the aorta on the left side of the spine ; they pass outwards, across the
bodies of the vertebrse, to the intercostal spaces, being covered by the pleura,
the oesophagus, thoracic duct, sympathetic nerve, and the vena azygos major;
the left passing beneath the superior intercostal vein, the vena azygos minor,
and sympathetic. In the intercostal spaces, each artery divides into two
branches ; an anterior, or proper intercostal branch ; and a posterior, or dorsal
branch.
The anterior hranch passes outwards, at first lying upon the External inter-
costal muscle, covered in front by the pleura and a thin fascia. It then passes
between the tAvo layers of Intercostal muscles, and, having ascended obliquely
to the lower border of the rib above, divides, near the angle of that bone, into
two branches: of these the larger runs in the groove, on the lower border of
524
ARTERIES,
the rib above ; tlie smaller branch, along the upper border of the rib below ;
passing forward, they supply the Intercostal muscles, and anastomose with the
anterior intei'bostal branches of the internal mammary, and with the thoracic
branches of the axillary artery. The first aortic intercostal anastomoses with
the superior intercostal, and the last three pass between the abdominal muscles,
inosculating with the epigastric in front, and with the phrenic and lumbar
arteries. Each intercostal arteiy is accompanied by a vein and nerve, the former
being above, and the latter below, except in the upper intercostal spaces, where
the nerve is at first above the artery. The arteries are protected from pressure
during the action of the Intercostal muscles^ by fibrous arches thrown across, and
attached by each extremity to the bone.
Fiff. 319. — The Abdominal Aorta and its Branches.
The 'posterior or dorsal Iranch, of each intercostal artery, passes backwards to
the inner side of the anterior costo-transvcrse ligament, and divides into a spinal
ABDOMINAL AORTA.
525
branch, wliicli supplies the vertebrae, the spinal cord and its membranes, and a
muscular branch, which is distributed to the muscles and integument of the
back.
The Abdominal Aorta. (Fig. 319.)
The Abdominal Aorta commences at the aortic opening of the Diaphragm, in
front of the body of the last dorsal vertebra, and descending a little to the left
side of the vertebral column, terminates on the body of the fourth lumbar verte-
bra, commonly a little to the left of the middle line,^ where it divides into the two
common iliac arteries. It diminishes rapidly in size, in consequence of the
many large branches which it gives off. As it lies upon the bodies of the verte-
bree, the curve which it describes is convex forwards, the greatest convexity
corresponding to the third lumbar vertebra, which is a little above and to the
left side of the umbilicus.
Relations. It is covered, in front ^ by the lesser omentum and stomach, behind
which are the branches of the coeliac axis, and the solar plexus ; below these,
by the splenic vein, the pancreas, the left renal vein, the transverse portion of
the duodenum, the mesentery, and aortic plexus. Behind^ it is separated from
the lumbar vertebrae by the left lumbar veins, the receptaculum chyli, and
thoracic duct. On the right side^ it is in relation with the sujDcrior vena cava
(the right crus of the Diaphragm being interposed above), the vena azygos,
thoracic duct, and right semilunar ganglion; on the left side, with the sympa-
thetic nerve, and left semilunar ganglion.
Plan OF THE Eelations of the Abdominal Aorta.
In front.
Lesser omentum and stomach.
Branches of cceliac axis and solar plexus.
Splenic vein.
Pancreas.
Left renal vein.
Transverse duodenum.
Mesentery.
Aortic plexus.
Right side.
Right crus of Diaphragm.
Inferior vena cava.
Vena azygos.
Thoracic duct.
Right semilunar ganglion.
Left side.
Sympathetic nerve.
Left semilunar ganglion.
Behind.
Left lumbar veins.
Receptaculum chyli.
'J'horacic duct.
Vertebral column.
Surgical Anatomy. Aneurisms of the abdominal aorta near the coeliac axis communicate in
nearly equal proportion with the anterior and posterior parts of the artery.
When an aneurismal sac is connected with the back part of the abdominal aorta, it usually
produces absorption of the bodies of the vertebra, and forms a pulsating tumor, that presents
itself in the left hypochondriac or epigastric regions, accompanied by symptoms of disturbance
of the alimentary canal. Pain is invariably present, and is usually of two kinds — a fixed and
constant pain in the back, caused by the tumor pressing on or displacing the branches of the
solar plexus and splanchnic nerves, and a sharp lancinating pain, radiating along those branches
of the lumbar nerves which are pressed on by the tumor; hence the pain in the loins, the testes,
' Prof. Lister, having accurately examined 30 bodies in order to ascertain the exact point of
termination of this vessel, found it "either absolutely, or almost absolutely, mesial in 15. M'hile
in 13 it divinted more or less to the left, and in 2 was slightly to the right." — Syst. of Surg.,
edited by T. Holmes, 2d ed. vol. v. p. 652.
526 ARTERIES.
■(he liypogastriutn, and in the lower limb (usually of the left side). This form of aneurism usually
bursts into the yjeritoneal cavity, or behind the peritoneum, in the left hypochondriac region ; or
it may form a large aneurismal sac, extending down as low as Poupart's ligament; hemorrhage
in these cases being generally very extensive, but slowly produced, and not rapidly fatal.
When an aneurismal sac is connected with the front of the aorta near the cceliac axis, it forms
a pulsating tumor in the left hypochondriac or epigastric regions, usually attended with symptoms
of disturbance of the alimentary canal, as sickness, dyspepsia, or constipation, and accompanied
by pain, which is constant, but nearly always fixed in the loins, epigastrium, or some part of the
abdomen ; the radiating pain being rare, as the lumbar nerves are seldom implicated. This form
of aneurism may burst into the peritoneal cavity, or behind the peritoneum, between the layers
of the mesentery, or, more rarely, into the duodenum ; it rarely extends backwards so as to affect
the spine.
The abdominal aorta has been tied several times, and although none of the patients permanently
recovered, still, as one of them lived as long as ten days, the possibility of the re-establishment
of the circulation may be considered to be proved. In the lower animals this artery is often
successfully tied. The vessel may be reached in several wa!ys. In the original operation, per-
formed by Sir A. Cooper, an incision was made in the linea alba, the peritoneum opened in front,
the finger carried down amongst the intestines towards the spine, the peritoneum again opened
behind, by scratching through the mesentery, and the vessel thus reached. Or either of the
operations, described below, for securing the common iliac artery, may, by extending the dissec-
tion a sufficient distance upwards, be made use of to expose the aorta. The chief difficulty in the
dead subject consists in isolating the artery, in consequence of its great depth ; but in the living
subject, the embarrassment resulting from the proximity of the aneurismal tumor, and the great
probability of disease in the vessel itself, add to the dangers and difficulties of this formidable
operation so greatly, that it is very doubtful whether it ought ever to be performed.
The collateral circulation would be carried on by the anastomosis between the internal mam-
mary and the epigastric; by the free communication between the superior and inferior mesenteries,
if the ligature were placed above the latter vessel ; or by the anastomosis between the inferior
mesenteric and the internal pudic, when (as is more common) the point of ligature is below the
origin of the inferior mesenteric; and possibly by the anastomoses of the lumbar arteries with
the branches of the internal iliac.
The circulation through the abdominal aorta may be commanded, in thin persons, by firm
pressure with the fingers. A tourniquet has been invented for this purpose, which is of the
greatest use in amputation at the hip-joint and some other operations.
Branches of the Abdominal Aorta.
Phrenic.
[ Gastric. Eenal.
Coeliac axis, -s Hepatic, Spermatic.
( Splenic. Inferior mesenteric.
Superior mesenteric. Lumbar.
Suprarenal. Sacra media.
Tlie branches may be divided into two sets: 1. Those supplying the viscera.
2. Those distributed to the walls of the abdomen.
Visceral Branches. Parietal Branches.
{Gastric. Phrenic.
Hepatic. Lumbar.
Splenic. Sacra media.
Superior mesenteric.
Inferior mesenteric.
Suprarenal. Eenal. Spermatic.
CcELiAC Axis. (Fig. 320.^
To expose tills artery, raise the liver, draw down the stomach, and then tear llu'ough the layers
of the le.sser omentum.
The Coeliac Axis is a short thick trunk, about half an inch in length, which
arises from the aorta, opposite the margin of the Diaphragm, and, passing nearly
horizontally forwards (in the erect posture), divides into three large branches,
the ga.stric, hepatic, and splenic, occasionally giving off one of the phrenic
arteries.
HEPATIC.
527
Rdations. It is covered by the lesser omentum. On tlie right side, it is in
relation witli the right semilunar ganglion, and the lobus Spigelii ; on the left
side, with the left semilunar ganglion and cardiac end of the stomach. Beloio,
it rests upon the upper border of the pancreas.
The Gastric Artery ( Coronaria VentricuU\ the smallest of the three branches
of the coeliac axis, passes upwards and to the left side, to the cardiac orifice of
the stomach, distributing branches to the oesophagus, which anastomose with
the aortic oesophageal arteries; others supply the cardiac end of the stomach,
inosculating with branches of the splenic artery: it then passes from left to
right, along the lesser curvature of the stomach to the pylorus, lying in its
course between the layers of the lesser omentum, and giving branches to both
surfaces of the organ: at its termination it anastomoses with the pyloric branch
of the hepatic.
Fiff. 320.
-The Cceliac Axis and its Branches, the Liver having been raised, and
the Lesser Omentum removed.
The Hepatic Artery in the adult is intermediate in size between the gastric
and splenic ; in the foetus, it is the largest of the three branches of the coeliac
axis. It passes upwards to the right side, between the layers of the lesser
omentum, and in front of the foramen of Winslow, to the transverse fissure of
the liver, where it divides into two branches, right and left, which supply the
corresponding lobes of that organ, accompanying the ramifications of the vena
portas and hepatic duct. The hepatic artery, in its course along the right border
of the lesser omentum, is in relation with the ductus communis choledochus and
portal veins, the duct lying to the right of the artery, and the vena port^e behind.
528
ARTERIES.
Its brandies are the
Pyloric.
Gastro-duodenalis. i Gastro-epiploica dextra.
Cystic.
Pancreatico-duodenalis superior.
The pyloric branch arises from the hepatic, above the pylorus, descends to the
pyloric end of the stomach, and passes from right to left along its lesser curva-
ture, supplying it with branches, and inosculating with the gastric artery.
The yastro-duodenalis (Fig. 321) is a short but large branch, which descends
behind the duodenum, near the pylorus, and divides at the lower border of the
stomach into two branches, the gastro-epiploica dextra and the pancreatico-
duodenalis superior. Previous to its division, it gives off two or three small
inferior p3doric branches to the pyloric end of the stomach and pancreas.
Fig. 321. — The Coeliac Axis and its Brandies, the Stomacli having been raised, aud
the Transverse Mesocolon removed.
+p (Irettt
The fjastro-ejnploica dextra runs from right to left along the greater curvature
of the stomach, between the layers of the great omentum, anastomosing_ about
the middle of the lower border of the stoma'ch with the gastro-e])iploica sinistra
from the splenic artery. This vessel gives oft' nnmorous branches, some of winch
ascend to supply both surfaces of the stomach, whilst others descend to supply the
great omentnm.
The pancrraiico-duodcnalis 5?/;>('r/o?- descends along the contiguous margins of
SUPERIOR MESENTERIC. 529
tile duodenum and pancreas. It supplies botTi tliese organs, and anastomoses
witli the inferior pancreatico-duodenal branch of the superior mesenteric artery.
In ulceration of the duodenum, which frequently occurs in connection with
severe burns, this artery may be involved, and death may occur from hemor-
rhage into the intestinal canal.
The cystic artery. (Fig. 320), usually a branch of the right hepatic, passes up-
wards and forwards along the neck of the gall bladder, and divides into two
branches, one of which ramifies on its free surface, the other between it and the
substance of the liver.
The Splenic Artery, in the adult, is the largest of the three branches of the
coeliac axis, and is remarkable for the extreme tortuosity of its course. It passes
horizontally to the left side behind the upper border of the pancreas, accompanied
by the splenic vein, which lies below it ; and, on arriving near the spleen, divides
into branches, some of which enter the hilum of that organ to be distributed to
its structure, whilst others are distributed to the great end of the stomach.
The branches of this vessel are : — ■
Pancreaticse parvee. Gastric (Yasa brevia).
Pancreatica magna. Gastro-epiploica sinistra.
The pancreatic are numsrous small branches derived from the splenic as it
runs behind the upper border of the pancreas, supplying its middle and left parts.
One of these, larger than the rest, is given oft' from the splenic near the left
extremity of the pancreas ; it runs from left to right near the posterior surface
of the gland, following the course of the pancreatic duct, and is called iYlq pan-
creatica magna. These vessels anastomose with the pancreatic branches of the
pancreatico-duodenal arteries.
The gastric (vasa brevia) consist of from five to seven small branches, which
arise either from the termination of the splenic artery, or from its terminal
branches ; and passing from left to right, between the layers of the gastro-splenic
omentum, are distributed to the great curvature of the stomach ; anastomosing
with branches of the gastric and gastro-epiploica sinistra arteries.
The gastro-epiploica sinistra, the largest branch of the splenic, runs from left
to right along the great curvature of the stomach, between the layers of the
great omentum ; and anastomoses with the gastro-epiploica dextra. In its course
it distributes several branches to the stomach, which ascend upon both surfaces ;
others ascend to supply the omentum.
Superior Mesenteric Artery. (Fig. 822,)
In order to expose this vessel, raise the great omentuTn and transverse colon, draw down the
small intestines, and cut through the peritoneum where the transverse mesocolon and mesentery
join: the artery will then be exposed, just as it issues from beneath the lower border of the
pancreas.
The Superior Mesenteric Artery supplies the whole length of the small
intestine, except the first part of the -duodenum ; it also supplies the coecum,
ascending and transverse colon : it is a vessel of large size, arising from the fore
part of the aorta, about a quarter of an inch below the coeliac axis; being covered
at its origin by the splenic vein and pancreas. It passes forwards, between the
pancreas and transverse portion of the duodenum, crosses in front of this portion
of the intestine, and descends between the layers of the mesentery to the right
iliac fossa, where it terminates, considerably diminished in size. In its course it
forms an arch, the convexity of which is directed forwards and downwards to
the left side, the concavity backwards and upwards to the right. It is accom-
panied by the superior mesenteric vein, and is surrounded by the superior
mesenteric plexus of nerves. Its branches are the
Inferior pancreatico-duodenal. Ileo- colic.
Yasa intestini tenuis. Colica dextra.
Colica media,
3i
530
ARTERIES,
The inferior pancreatico-duodenal is given off from the superior mesenteric
behind the pancreas, and is distributed to the head of the pancreas, with the
transverse and descending portions of the duodenum ; anastomosino- with tlie
superior pancreatico-daodenal arterj.
Fig. 322.— The Superior Mesenteric Artery and its Branches.
The vasa intestini tenuis arise from the convex side of the superior mesenteric
artery. They are usually from twelve to fifteen in number, and are distributed
to the jejunum and ileum. They run parallel with one another between the
layers of the mesentery; each vessel dividing into two branches, which unite
with a similar branch on each side, forming a series of arches, the convexities
of which are directed towards the intestine. From this first set of arches
branches arise, which again unite with similar branches from either side, and
thus a second series of arches is formed ; and from these latter, a third, and a
fourth, or even fifth series of arches are constituted, diminishing in size the
nearer they approach the intestine. From the terminal arches numerous small
straight vessels arise which encircle the intestine, uijon which llicy arc distri-
buted, ramifying thickly between its coats.
The ileo-colic artery is the lowest branch given olT from lhc concavity of the
superior mesenteric artery. It dcsccncls between the layers of the mesentery to
the right iliac fossa, where it divides into two branches. Of these, the inferior
one inosculates with the lowest branches of the vasa intestini tenuis, from the
INFERIOR MESENTERIC. 531
convexity of wliicli brandies proceed to supply the termination of the ileum,
the coecum and appendix coeci, and the ileo coecal valve. The superior division
inosculates with the colica dextra, and supplies the commencement of the colon.
The colica dextra arises from about the middle of the concavity of the superior
mesenteric artery, and, passing beneath the peritoneum to the middle of the
ascending colon, divides into two branches : a descending branch, which inoscu-
lates with the ileo-colic ; and an ascending branch, which anastomoses with the
colica media. These branches form arches, from the convexity of which vessels
are distributed to the ascending colon. The branches of this vessel are covered
with peritoneum only on their anterior aspect.
The colica media arises from the upper part of the concavity of the superior
mesenteric, and, passing forwards between the layers of the transverse meso-
colon, divides into two branches : the one on the right side inosculating with
the colica dextra; that on the left side, with the colica sinistra, a branch of the
inferior mesenteric. From the arches formed by their inosculation, branches
are distributed to the transverse colon. The branches of this vessel lie between
two layers of peritoneum.
Inferior Mesenteric Artery. (Fig. 323.)
Ill order to expose this vessel, draw the small intestines and mesentery over to the right side
of the abdomen, raise the transverse colon towards the thorax, and divide the peritoneum cover-
ing the left side of the aorta.
The Inferior Mesenteric Artery supplies the descending and sigmoid
flexure of the colon, and the greater part of the rectum. It is smaller than the
superior mesenteric ; and arises from the left side of the aorta, between one and
two inches above its division into the common iliacs. It passes downwards to
the left iliac fossa, and then descends -between the layers of the meso-rectum,
into the pelvis, under the name of the superior hemorrhoidal artery. It lies at
first in close relation w^ith the left side of the aorta, and then passes in front of
the left common iliac artery. Its branches are the
Colica sinistra. Sigmoid.
Superior hemorrhoidal.
The colica sinistra passes behind the peritoneum, in front of the left kidney,
to reach the descending colon, and divides into two branches: an ascending
branch, which inosculates with the colica media; and a descending branch, which
anastomoses with the sigmoid artery. From the arches formed by these inoscu-
lations, branches are distributed to the descending colon.
The sigmoid artery runs obliquely downwards across the Psoas muscle to the
sigmoid flexure of the colon, and divides into branches which supply that part
of the intestine ; anastomosing above, with the colica sinistra ; and below, with
the superior hemorrhoidal artery. This vessel is sometimes replaced by three
or four small branches.
The superior hemorrhoidal artery .^ the continuation of the inferior mesenteric,
descends into the pelvis between the layers of the meso-rectum, crossing, in its
course, the ureter, and left common iliac vessels. Opposite the middle of the
sacrum, it divides into two branches, which descend one on each side of the
rectum, where they divide into several small branches, which are distributed
between the mucous and muscular coats of that tube, nearly as far as its lower
end; anastomosing with each other, with the middle hemorrhoidal arteries,
branches of the internal iliac, and with the inferior hemorrhoidal branches of
the internal pudic.
The student should especially remark, that the trunk of the vessel descends
along the back part of the rectum as far as the middle of the sacrum before it
divides; this is about a finger's length or four inches from the anus. In disease
of this tube, the rectum should never be divided beyond this point in that
direction, for fear of involving this artery.
532
ARTERIES,
The SuPEARENAL ARTERIES (Fig. 319) are two small vessels wliicli arise, one
on each, side of the aorta, opposite the superior mesenteric artery. They pass
obliquely upwards and outwards to the under surface of the suprarenal capsules,
to which they are distributed, anastomosing with capsular branches from the
phrenic and renal arteries. In the adult these arteries are of small size ; in the
foetus they are as large as the renal arteries.
Fig. 323. — The Inferior Mesenteric and its Branches.
ItlFeitor Tlirinorrhciihil
The Eenal Arteries are two large trunks, which arise from the sides of the
aorta, immediately below the superior mesenteric artery. Bach is directed out-
wards, so as to form nearly a right angle with the aorta. The right is longer
than the left, on account of the position of the aorta ; it passes behind the infe-
rior vena cava. The left is somewhat higher than the right. Previously to
entering the kidney, each artery divides into four or five branches which are
distributed to its substance. At the hilum, these branches lie between the
renal vein and ureter, the vein being usually in front, tlic ureter behind. Each
vessel gives off" some small branches to the suprai'enal capsules, the ureter and
the surrounding cellular membrane and muscles.
The Spermatic Arteries are distributed to the testes in the male, and to the
ovaria in lhe female. Tliey are two slender vessels, of considerable length,
which arise from the front of the aorta, a little below the renal arteries. Each
artery passes obliquely outwards, and downwards, behind the })critoncum.
LUMBAR. 533
crossing the ureter, and resting on the Psoas muscle, the right spermatic lying
in front of the inferior vena cava, the left behind the sigmoid flexure of the
colon. On reaching the margin of the pelvis, each vessel passes in front of the
corresponding external iliac artery, and takes a different course in the two sexes.
In the male^ it is directed outwards, to the internal abdominal ring, and ac-
companies the other constituents of the spermatic cord along the spermatic canal
to the testis, where it becomes tortuous, and divides into several branches, two
or three of which accompany the vas deferens, and supply the epididymis,
anastomosing with the artery of the vas deferens; others pierce the back part
of the tunica albuginea, and supply the substance of the testis.
In the female^ the spermatic arteries (ovarian) are shorter than in the male,
and do not pass out of the abdominal cavity. On arriving at the margins of
the pelvis each artery passes inwards, between the two laminas of the broad
ligament of the uterus, to be distributed to the ovary. One or two small branches
supply the Fallopian tube ; another passes on to the side of the uterus, and
anastomoses -with the uterine arteries. Other offsets are continued along the
round ligament, through the inguinal canal, to the integument of the labium
and groin.
At an early period of foetal life, when the testes lie by the side of the spine,
below the kidneys, the spermatic arteries are short ; but as these organs descend
from the abdomen into the scrotum, the arteries become gradually lengthened.
The Phrexic Arteries are two small vessels, which present much variety
in their origin. They m.ay arise separately from the front of the aorta, imme-
diately below the coeliac axis, or by a common trunk, which may spring either
from the aorta or from the coeliac axis. Sometimes one is derived from the
aorta, and the other from one of the renal arteries. In only one out of thirty-
six cases examined did >,these arteries arise as two separate vessels from the
aorta. They diverge from one another across the crura of the Diaphragm, and
then pass obliquely upwards and outwards upon its under surface. The left
phrenic passes behind the oesophagus, and runs forwards on the left side of the
oesophageal opening. The right phrenic passes behind the liver and inferior
vena cava, and ascends along the right side of the aperture for transmitting
that vein. Near the back part of the central tendon, each vessel divides into
two branches. The internal branch runs forwards to the front of the thorax,
supplying the Diaphragm, and anastomosing with its fellow of the opposite side,
and with the musculo-phrenic, a branch of the internal mammary. The exter-
nal branch passes towards the side of the thorax, and inosculates with the inter-
costal arteries. The internal branch of the right phrenic gives off a few vessels
to the inferior vena cava ; and the left one some branches to the oesophagus.
Each vessel also sends capsular branches to the suprarenal capsule of its own
side. The spleen on the left side, and the liver on the right, also receive a few
branches from these vessels.
The Lumbar Arteries are analogous to the intercostal. They are usually
four in number on each side, and arise from the back part of the aorta, nearly
at right angles with that vessel. They pass outwards and backwards, around
the sides of the body of the corresponding lumbar vertebra, behind the sympa-
thetic nerve and the Psoas muscle ; those on the right side being covered by the
inferior vena cava, and the two upper ones on each side by the crura of the
Diaphragm. In the interval between the transverse processes of the vertebrae
each artery divides into a dorsal and an abdominal branch.
The dorsal hranch gives off, immediately after its origin, a spinal branch, which
enters the spinal canal ; it then continues its course backwards, between the
transverse processes, and is distributed to the muscles and integument of the
back, anastomosing with each other, and with the posterior branches of the
intercostal arteries.
The spinal branch^ besides supplying offsets which run along the nerves to the
dura mater and cauda equina, anastomosing with the other spinal arteries, divides
534 AETERIES.
into two branches, one of wliicli ascends on the posterior surface of the body of
the vertebra above, and the other descends on the posterior surface of the body
of the vertebra below, both vessels anastomosing with similar branches from
neighboring spinal arteries. The inosculations of these vessels on each side,
throughout the whole length of the spine, form a series of arterial arches behind
the bodies of the vertebree, which are connected with each other, and with a
median longitudinal vessel, extending along the middle of the posterior surface
of the bodies of the vertebrae, by transverse branches. From these vessels
offsets are distributed to the periosteum and bones.
The ahdominal branches pass outwards, behind the Quadratus lumborum, the
lowest branch occasionally in front of that muscle, and, being continued between
the abdominal muscles, anastomose with branches of the epigastric and internal
mammary in front^ the intercostals above, and those of the ilio- lumbar and
circumflex iliac, beloiv.
The Middle Sacral Artery is a small vessel, about the size of a crov^-quill,
which arises from the back part of the aorta, just at its bifurcation. It descends
upon the last lumbar vertebra, and along the middle line of the front of the
sacrum, to the upper part of the coccyx, where it anastomoses with the lateral
sacral arteries, and terminates in a minute branch, which runs clown to the
situation of the body presently to be described as " Luschka's gland." From it,
branches arise which run through the meso-rectum, to supply the posterior
surface of the rectum. Other branches are given off on each side which anasto-
mose with the lateral sacral arteries, and send off small offsets which enter the
anterior sacral foramina.
Coccygeal Gland, or Lusclikci's Oland. — Lying near the tip of the coccyx in a
small tendinous interval formed by the union of the Levator ani muscles of
either side, and just above the coccygeal attachment of the Sphincter ani, is ^
small conglobate body, about as large as a lentil or a pea, first described by
Luschka,^ and named by him the coccygeal gland, but the real nature and uses of
which are doubtful, nor does it seem at present certain that it always exists.
Its most obvious connections are with the arteries of the part. It receives
comparatively large branches from the middle and lateral sacral arteries ; and
its structure, according to Julius Arnold,^ consists in great measure of dilated
arterial vessels. On this account Arnold proposes to call it not a gland, but
" glomerulus arterio-coccygeus." It is sometimes single, sometimes formed of
several lobes, surrounded by a very definite capsule, into which the sympathetic
filaments from the ganglion impar are to be traced and in which they are said
by some observers to terminate. The structure of the body is composed of a
number of cavities, which Luschka believes to be glandular follicles, but which
are regarded by Arnold as fusiform dilatations of the terminal branches from the
middle sacral arteries. Nerves pass into this little body both from the sympa-
thetic and from the fifth sacral, and in the interstices of the lobules nerve-cells
are described.
This body has been variously regarded as an appendage to the nervous or to
the arterial system. The former seems to be Luschka's view, the latter is
Arnold's.^ Arnold's view is supported by the observation of Dr. Macalister,*
that he has found in several birds the middle sacral arteries terminating in a
bunch of interlacing and anastomosing capillaries, but without any capsule ; and
' Dor IJirnnnhanq nnd die Sfensdriisedcfi Menschen, Berlin, 18G0 ; Anatnmie des Mensdicn,
Tuhiiifreii, 18C4, vol.'ii. pt,. 2, p. 187.
2 Vircliow, Ardi., 18G4, 5, 6; sec also Krause and Mcyor in ITcnlo niul rrciffor's Zeitscli.f.
ral. Mcdirin.
^ In a conrso of locturos rcfcntly dolivcrcfl at tlie Col]('^''e of Snrfjooiis, on the Povolopment
of llic IJrain, Mr. (JalU^iulcr sii.<,''^^c'st.s that LiiKclika's f^-land niiiy liavc the same relation to the
development of the npinal cord ii,s he proves tiie pineal and pituitary body to have to that of the
Virain. lir/'L Mcil. Jov.rn., June ].'{, lH7t.
'' BriLidi Medical Journal, dan. 11, IbGB.
COMMON ILIAC,
535
it is rendered in tlie liigliest degree probable, if Arnold's observation be correct,
that several small saccular bodies, of a somewbat similar kind, may be found
connected witli the middle sacral artery.
(For a more detailed description of this body, we would refer to the elaborate
account in " Luschka's Anatomic," and to the authorities quoted in Dr. Mac-
alister's paper, as well as to a monograph by Dr. W. Mitchell Banks, reprinted
in 1867 from the " Glasgow Medical Journal.")
Common Iliac Arteries.
The abdominal aorta divides into the two Common Iliac arteries. The bifur-
cation usually takes place on the left side of the body of the fourtli lumbar
vertebra. This point corresponds to the left side of the umbilicus, and is on a
level with a line drawn from the highest point of one iliac crest to the other.
The common iliac arteries are about two inches in length ; diverging from the
termination of the aorta, they pass downwards and outwards to the margin of
the pelvis, and divide opposite the intervertebral substance, between the last
lumbar vertebra and the sacrum, into two branches, the external and internal
iliac arteries : the former supplying the lower extremity ; the latter, the viscera
and parietes of the pelvis.
The right common iliac is somewhat larger than the left, and passes more
obliquely across the body of the last lumbar vertebra. In front of it are the
peritoneum, the ileum, branches of the sympathetic nerve, and, at its point of
division, the ureter. Beliind, it is separated from the last lumbar vertebra by
the two common iliac veins. On its outer side^ it is in relation with the inferior
vena cava, and the right common iliac vein, above ; and the Psoas magnus
muscle below.
The left common iliac is in relation, in front, with the peritoneum, branches of
the sympathetic nerve, the rectu.m and superior hemorrhoidal artery; and is
crossed at its point of bifurcation by the ureter. The left common iliac vein
lies partly on the inner side, and partly beneath the artery ; on its outer side,
the artery is in relation with the Psoas magnus.
Branches. The common iliac arteries give off small branches to the perito-
neum. Psoas muscles, ureters, and the surrounding cellular membrane, and occa-
sionally give origin to the ilio-lumbar, or renal arteries.
Plan of the Eelations of the Common Iliac Arteries.
In front.
Peritoneum.
Small intestines.
Sympathetic nerves.
Ureter.
In front.
Peritoneum.
Sympathetic nerves.
Eectum.
Superior hemorrhoidal artery.
Ureter.
Outer side.
Yena cava.
Eight common
iliac vein.
Psoas muscle.
Inner side.
Left common
iliac vein.
Outer side.
Psoas muscle.
Behind.
Right anid Ijclt common
iliac veins.
Behind.
Lett common
iliac vein.
Peculiarities. The point of origin varies according to the bifurcation of the aorta. In three-
fourths of a large number of cases, the aorta bifurcated cither upon the fourth lumliar vertebra,
or upon the intervertebral disk between it and the fifth; the bifurcation being, in one case out
of nine below, and in one out of eleven above this point. In ten out of every thirteen cases, the
vessel bifurcated within half an inch above or below the level of the crest of the ilium; more
frequently below than above.
536
ARTERIES.
The point of division is subject to grea*' variety. In two-tliirds of a larofe number of cases it
was between the last lumbar vertebra and the upper border of the sacrum ; being above that
point in one case out of eight, and below it in one case out of six. The left common iliac artery
divides lower down more frequently than the right.
The relative length, also, of the two common iliac arteries varies. The right common iliac was
the longer in sixty-three cases; the left in fifty-two ; whilst they were both equal in fifty-three.
The length of the arteries varied in five-sevenths of the cases examined, from an inch and a half
to three inches; in about half of the remaining cases, the artery was longer; and in the other
half, shorter; the minimum length being less than half an inch, the maximum four and a half
inches. In one instance, the right common iliac was found wanting, the external and internal
iliacs arising directly from the aorta.
Surgical Anatomy. 1'he application of a ligature to the common iliac artery may be required
on account of aneurism or hemorrhage, implicating the external or internal iliacs, or on account
of secondary hemorrhage after amputation of the thigh high up. It has been seen that the origin
of this vessel corresponds to the left side of the umbilicus on a level with a line drawn from the
highest point of one iliac crest to the opposite one, and its course to a line extending from the
left side of the umbilicus downwards towards the middle of Poupart's ligament, 'i'he line of
Fig. 324. — Arteries of the Pelvis.
incisidii rcquiri'd in (ho first stops of an operation for securing this vessel, would materially depend
upon the naliirc dl' the disease. Jf tiic sin-gcon select tiio iliac region, a curved incision, about
five inches in length, may be made, (■(immencing on the left side of the umbilicns, carried oiitwards
towards the anterior superior iliac spine, and then along tlie upper l)order of Poupart's ligament,
as far as its middle. I'.ut if the anenrismal tumor should extend high up in the abdomen, along
the external iliac, it is better to select tlic^ side of the abdonuui, approaching the artery from
above, liy making an incision IVoni ruin- to livi^ iiiclirs in length, IVom about two inches above and
INTERNAL ILIAC. 537
to the left of the umbilicus, carried outwards in a curved direction towards the lumbar region,
and terminating a little below the anterior superior iliac spine. The abdominal muscles (in either
ctise) having been cautiously divided in succession, the transversalis fascia must be carefully cut
through, and the peritoneum, together with the ureter, separated from the artery, and pushed
aside ; the sacro-iliac articulation must then be felt for. and upon it the vessel will be felt pul-
sating, and may be fully exposed in close connection with its accompanying vein. On the right
side, both common iliac veins, as well as the inferior vena cava, are in close connection with the
artery, and must be carefully avoided. On the left side, the vein usually lies on the inner side,
and behind the artery ; but it occasionally happens that the two common iliac veins are joined
on the left instead of the right side, which would add much to the difficulty of an operation in
such a case. The common iliac artery may be so short that danger may be apprehended from
secondary hemorrhage if a ligature is applied to it. It would be preferable, in such a case, to
tie both the external and internal iliacs near their origin.
Collateral Circulation. The principal agents in carrying on the collateral circulation after
the application of a ligature to the common iliac, are, the anastomoses of the hemorrhoidal
branches of the internal iliac, with the superior hemorrhoidal from the inferior mesenteric ; the
anastomoses of the uterine and ovarian arteries, and of the vesical arteries of opposite sides ; of
the lateral sacral, with the middle sacral artery ; of the epigastric, with the internal mammary,
inferior intercostal and lumbar arteries; of the ilio-lumbar, with the last lumbar artery; of the
obturator artery, by means of its pubic branch, with the vessel of the opposite side, and with
the internal epigastric ; and of the gluteal with the posterior branches of the sacral arteries.
Internal Iliac Artery. (Fig. 324.)
The Internal Iliac Artery supplies tlie walls and viscera of the pelvis, the
generative organs, and inner side of the thigh. It is a short, thick vessel,
smaller than the external iliac, and about an inch and a half in length, which
arises at the point of bifurcation of the common iliac ; and, passing downwards
to the upper margin of the great sacro-sciatic foramen, divides into two large
trunks, an anterior and posterior; a partially obliterated cord, the hypogastric
artery, extending from the extremity of the vessel forwards to the bladder.
Relations. In front, with the ureter, which separates it from the peritoneum.
Belmid, with the internal iliac vein, the lumbo- sacral nerve, and Pyriformis
muscle. By its outer side, near its origin with the Psoas muscle.
Plan of the Eelations of the Internal Iliac Artery.
In front.
Peritoneum.
Ureter.
Outer side.
Psoas magnus.
Behind.
Internal iliac vein.
lAinibo-sacral nerve.
Pyriformis muscle.
In the foetus, the internal iliac artery (hypogastric) is twice as large as the
external iliac, and appears to be the continuation of the common iliac. Passing-
forwards to the bladder, it ascends along the sides of that viscus to its summit,
to which it gives branches ; it then passes upwards along the back part of the
anterior wall of the abdomen to the umbilicus, converging towards its fellow
of the opposite side. Having passed through the umbilical opening, the two
arteries twine round the umbilical vein, forming with it the umbilical cord ; and,
ultimately, ramifying in the placenta. The portion of the vessel within the
abdomen is called the hypogastric artery ; and that external to that cavity, the
umbilical artery.
Athirth, when the placental circulation ceases, the upper portion of the hypo-
gastric artery, extending from the summit of the bladder upwards to the umbili-
538 ARTERIES.
ciis, contracts, and ultimately dwindles to a solid fibrous cord; bat tbe lower
portion, extending from its origin (in what is now the internal iliac artery) for
about an inch and a half to the wall of the bladder, and thence to the summit
of that organ, is not totally impervious, though it becomes considerably reduced
in size ; and serves to convey blood to the bladder, under the name of the superior
vesical artery.
Pecxdiarities as regards length. In two- thirds of a large number of cases, the length of the
internal iliac varied between an inch and an inch and a half; in the remaining third, it was
more frequently longer than shorter, the maximum length being three inches, the minimum half
an inch.
'I'he lengths of the common and internal iliac arteries bear an inverse proportion to each other,
the internal iliac artery being long when the common iliac is short, and vice versa.
As regards its place of division. The place of division of the internal iliac varies between the
upper margin of the sacrum, and the upper border of the sacro-sciatic foramen.
The arteries of the two sides in a series of cases often differed in length, but neither seemed
constantly to exceed the other.
Surgical Anatomy/. The application of a ligature to the internal iliac artery may be required
in cases of aneurism or hemorrhage affecting one of its branches. The vessel may be secured by
making an incision through the abdominal parietes in the iliac region, in a direction and to an
extent similar to that for securing the common iliac ; the transversalis fascia having been cau-
tiously divided, and the peritoneum pushed inwards from the iliac fossa towards the pelvis, the
finger may feel the pulsation of the external iliac at the bottom of the wound ; and, by tracing
this vessel upwards, the internal iliac is arrived at, opposite thesacro-iliac articulation. Tt should
be remembered, that the vein lies behind, and on the right side, a little external to the artery,
and in close contact with it; the ureter and peritoneum, which lie in front, must also be avoided.
The degree of facility in applying a ligature to this vessel will mainly depend upon its length.
It has been seen that, in the great majority of the cases examined, the artery was short, varying
from an inch to an inch and a half ; in these cases, the artery is deeply seated in the pelvis : when,
on the contrary, the vessel is longer, it is found partly above that cavity. If the artery is very
short, as occasionally happens, it would be preferable to apply a ligature to the common iliac, or
upon the external and internal iliacs at their origin.
Collateral Circulation. In Prof. Owen's dissection of a case in which the internal iliac artery
had been tied by Stevens ten years before death, for aneurism of the sciatic artery, the internal
iliac was found impervious for about an inch above the point where the ligature had been applied ;
but the obliteration did not extend to the origin of the external iliac, as the iliolumbar artery
arose just above this point. Below the point of obliteration, the artery resumed its natural
diameter, and continued so for half an inch ; the obturator, lateral sacral, and gluteal, arising
in succession from the lateral portion. The obturator artery was entirely obliterated. The late-
ral sacral artery was as large as a crow's quill, and had a very free anastomosis with the artery
of the opposite side, and with the middle sacral artery, 'i'he sciatic artery was entirely oblite-
rated as far as its point of connection with the aneurismal tumor ; but, on the distal side of the
sac, it was continued down along the back of the thigh nearly as large in size as the femoral,
being pervious about an inch below the sac by receiving an anastomosing vessel from the profunda.'
'I'he circulation was carried on by the anastomoses of the uterine and ovarian arteries ; of the
opposite vesical arteries; of the hemorrhoidal branches of the internal iliac with those from the
inferior mesenteric; of the obturator artery, by means of its pubic branch, with the vessel of the
opposite side, and with the epigastric and internal circumflex ; of the circumflex and perforating
branches of the femoral, with tlie sciatic; of the gluteal, with the posterior l)ranches of the sacral
arteries; of the iliolumbar, with the last lumbar; of the lateral sacral, with the middle sacral;
and of the circumflex iliac, with the ilio-lumbar and gluteal.
Branches of the Internal Iliac,
From the Anterior Trunk. From the Posterior Trunk.
Superior vesical. Ilio-lumbar.
Middle vesical. Lateral sacral.
Inferior vesical. Ghitcal.
Middle hemorrhoidal.
Obturator.
Internal pudic.
Sciatic.
7- /. 7 ) Uterine.
In female. | ^^^^.^^^^
The superior vesicle is that part of the foetal hypogastric artery which remains
' Medico-CJiirnrgical Trans., vo\. xvi.
OBTURATOR. 539
j)ervious after birtli. It extends to the side of tlie bladder, distributing niime-
rous branches to the body and fundus of the organ. From one of these a slender
vessel is derived, which accompanies the vas deferens in its course to the testis,
where it anastomoses with the spermatic artery. This is the artery of the vas
deferens. Other branches supply the ureter.
The raiddle vesicle^ usually a branch of the superior, is distributed to the base
of the bladder, and under-surface of the vesiculee seminales.
The inferior vesical arises from the anterior division of the internal iliac, in
common with the middle hemorrhoidal, and is distributed to the base of the
bladder, the prostate gland, and vesiculge seminales. The branches distributed
to the prostate communicate with the corresponding vessel of the opposite side.
The middle hemorrhoidal artery usually arises together with the preceding
vessel. It supplies the rectum, anastomosing with the other hemorrhoidal
arteries.
The uterine artery passes downwards from the anterior trunk of the internal
iliac to the neck of the uterus. Ascending, in a tortuous course on the side of
this viscus, between the layers of the broad ligament, it distributes branches to
its substance, anastomosing, near its termination, with a branch from the ovarian
artery. Branches from this vessel are also distributed to the bladder and ureter.
The vaginal artery is analogous to the inferior vesical in the male ; it descends
upon the vagina, supplying its mucous membrane, and sending branches to the
neck of the bladder and contiguous part of the rectum.
The Obturator Artery usually arises from the anterior trunk of the internal
iliac, frequently from the posterior. It passes forwards below the brim of the
pelvis, to the canal in the upper border of the obturator foramen, and escaping
from the pelvic cavity through this aperture, divides into an internal and an
external branch. In the pelvic cavity this vessel lies upon the pelvic fascia,
beneath the peritoneum, and a little below the obturator nerve ; and whilst
passing through the obturator foramen, is contained in an oblique canal, formed
by the horizontal branch of the pubes, above, and the arched border of the obtu-
rator membrane, below.
Branches. Within the pelvis.^ the obturator artery gives off an iliac hranch to
the iliac fossa, which supplies the bone, and the Iliacus muscle, and anastomoses
with the ilio-lumbar artery ; a vesical hranch, which runs backwards to supply
the bladder ; and a pubic branch, which is given off' from the vessel just before
it leaves the pelvic cavity. This branch ascends upon the back of the pubes,
communicating with offsets from the epigastric artery, and with the correspond-
ing vessel of the opposite side. This branch is placed on the inner side of the
femoral ring. External to the 'pelvis, the obturator artery divides into an external
and an internal branch, which are deeply situated beneath the Obturator externus
muscle ; skirting the circumference of the obturator foramen, they anastomose at
the lower part of this aperture with each other, and with branches of the inter-
nal circumflex artery.
The internal branch curves inwards along the inner margin of the obturator
foramen, distributing branches to the Obturator muscles, Pectineus, Adductors,
and Gracilis, and anastomoses with the external branch, and with the internal
circumflex artery.
The external branch curves round the outer margin of the foramen, to the
space between the Gemellus inferior and Quadratus femoris, where it anasto-
moses with the sciatic artery. It supplies the Obturator muscles, anastomoses,
as it passes backwards, with the internal circumflex, and sends a branch to the
hip-joint through the cotyloid notch, which ramifies on the round ligament as
far as the head of the femur.
Peculiarities. In two out of every three cases the obturator arises from the internal iliac ; in
one case in 3|^, from the epie^astric; and in about one case in seventy-two by two roots from both
vessels. It arises in about the same proportion from the external iliac artery. The origin of the
obturator from the epigastric is not commonly found on both sides of the same body.
;40
ARTEEIES,
When the obturator artery arises at the front of the pelvis from the epigastric, it descends
almost vertically to the upper part of the obturator foramen. The artery in this course usually
lies in contact with the external iliac vein, and on the outer side of the femoral ring (Fig. 325,1);
in such cases it would not be endangered in the operations for femoral hernia. Occasionally,
however, it curves inwards along the free margin of Uimbernat's ligament (Fig. 325, 2), and under
such circumstances would almost completely encircle the neck of a hernial sac (supposing a hernia
to exist in such a case), and would be in great danger of being wounded if an operatioQ was
performed.
Fig. 325. — Variations in Origin and Course of Obturator Artery.
1 II
^^ n ' "t
Tlie Internal Pudic is tlie smaller of tbe two terminal branches of tlie ante-
rior trunk of tlie internal iliac, and supplies the external organs of generation.
It passes downwards and outwards to the lower border of the great sacro-sciatic
foramen, and emerges from the pelvis between the Pyriformis and Coccygeus
muscles ; it then crosses the spine of the ischium, and re-enters the pelvis through
the lesser sacro-sciatic foramen. The artery now crosses the Obturator internus
muscle, to the ramus of the ischium, being covered by the obturator fascia, and
situated about an inch and a half from the margin of the tuberosity ; it then
ascends forwards and upwards along the ramus of the ischiiTm, pierces the pos-
terior layer of the deep perineal fascia, and runs forwards along the inner margin
of the ramus of the pubes ; finally, it perforates the anterior layer of the deep
perineal fascia, and divides into its two terminal branches, the dorsal artery of
the penis, and the artery of the corpus cavernosum.
Relations. In the first part of its course, within the pelvis, it lies in front of
the Pyriformis muscle and sacral plexus of nerves, and on the outer side of the
rectum (on the left side). As it crosses the spine of the ischium, it is covered
by the Gluteus maximus, and great sacro-sciatic ligament. In the pelvis, it lies
on the outer side of the ischio-rectal fossa, upon the surface of the Obturator
internus muscle, contained in a fibrous canal formed by the obturator fascia and
the falciform process of the great sacro-sciatic ligament. It is accompanied by
the pudic veins, and the internal pudic nerve.
Peculiarities. The internal pndlc is sometimes smaller than usual, or fails to give off one or
two of its usual branches; in such cases, the deficiency is supplied by i)ranches derived from an
additional vessel, the accessory pudic, which generally arises from the pudic artery before its
exit from the great sacro-sciatic foramen, and passes forwards near the base of the bladder, on the
upper part of tlie prostate gland, to the perineum, where it gives off the branches, usually derived
from the pudic artery. The deficiency most frequently met with is that in which the internal
piulic ends as the artery of the bulb; the artery of the corpus cavernosum and artcria dorsalis
penis being derived from the accessory pudic. Or the pudic may terminate as the superlicial
perineal, the artery of the bulb being derived, with the other two branches, from the accessory
vessel.
'J'lie relation of the accessory pudic to the prostate gland and urethra, is of the greatest interest
in a surgical point of view, as this vessel is in danger of being wounded in the lateral operation of
lithotomy.
Branches. Within the pelvis, the internal pudic gives off several small
Tjranclics which supply the muscles, sacral nerves, and pelvic viscera. In the
perineum the following branches are given off: —
Inferior or external licmorrhoidal. Artery of the bulb.
Superficial pcrinoul. Artery of the cor]ius cavernosum.
Transverse perineal. D(jrsal artery of the penis.
INTERNAL PUDIC.
541
The external hemorrhoidal are two or three small arteries wliicli arise from
the internal puclic as it passes above the tuberosity of the ischium. Crossing
the ischio-rectal fossa, they are distributed to the muscles and integument of the
anal region.
Fiof. 326. — The Internal Pudic Arterv and its Brancliec.
The superficial 2^erineal artery supplies the scrotum and miiscles and integu-
ment of the perineum. It arises from the internal pudic, in front of the pre-
ceding branches, and piercing the lower border of the deep perineal fascia, runs
across the Transversus perinsei, and through the triangular space between the
Accelerator urinte and Erector penis, both of which it supplies, and is finally
distributed to the skin of the scrotum and dartos. In its passage through the
perineum it lies beneath the superficial perineal fascia.
The transverse perineal is a small branch which arises either from the internal
pudic, or from the superficial perineal artery as it crosses the Transversus
perin93i muscle. Piercing the lower border of the deep perineal fascia, it runs
transversely inwards along the cutaneous surface of the Transversus perimei
muscle, which it supplies, as well as the structures between the anus and bulb
of the urethra.
The artery of the bulb is a large but very short vessel which arises from the
internal pudic between the two layers of the deep perineal fascia, and passing
nearly transversely inwards, pierces the bulb of the urethra, in which it ramifies.
It gives off a, small branch which descends to supply Cowper's gland. This artery
is of considerable importance in a surgical point of view, as it is in danger of
being wounded in the lateral operation of lithotomy, an accident usually attended
542
ARTERIES.
in tlie adult witli alarming hemorrliage. Tlie vessel is sometimes very small,
occasionally wanting, or even double. It sometimes arises from the internal
pndic earlier than usual, and crosses the perineum to reach the back part of the
bulb. In such a case the vessel could hardly fail to be wounded in the per-
formance of the lateral operation for lithotomy. If, on the contrary, it should
arise from an accessory pudic, it lies more forward than usual, and is out of
danger in the operation.
The artery of the corpus cavernosum^ one of the terminal branches of the inter-
nal pudic, arises from that
Fig. 327.— The Arteries of the Gluteal and Posterior vessel while it is situated be-
Femoral Regions. , tween the crus penis and the
ramus of the pubes ; piercing
the crus penis obliquely, it
runs forwards in the corpus
cavernosum by the side of the
septum pectiniforme, to which
its branches are distributed.
The dorsal artery of the penis
ascends between the crus and
pubic symphysis, and piercing
the suspensory ligament, runs
forwards on the dorsum of the
penis to the glans, where it
divides into two branches,
which supply the glans and
prepuce. On the dorsum of
the penis, it lies immediately
beneath the integument, par-
allel with the dorsal vein, and
the corresponding artery of
the opposite side. It supplies
the integument and fibrous
sheath of the corjDus caverno-
sum.
The internal pudic artery in
tlie female is smaller than in
the male. Its origin and
course are similar, and there
is considerable analogy in the
distribution of its branches.
The superficial artery supplies
the labia pudenda ; the artery
of the bulb supplies the erec-
tile tissue of the bulb of the
vagina, whilst the two termi-
nal brandies supply the clito-
ris: the artery of the corpus
cavernosum, the cavernous
body of the clitoris ; and the
artcria dorsalis clitoridis, the
dorsum of that organ.
The Sciatic Artery (Fig.
827), tlic larger of the two
terminal branches of the ante-
rior trunk of ihc internal iliac, is distributed to the muscles on the back of the
pelvis. It passes down to the lower part of the great sacro-sciatic foramen,
i;>chind the internal pudic, resting on the sacral j)lcxus of nerves and Pyriformis
SuTjer. InUrnalAflUuli,
GLUTEAL. 543
muscle, and escapes from the pelvis between ttie Pjriformis and Coccygens. It
then descends in the interval between the trochanter major and tuberosity of
the ischium, accompanied by the sciatic nerves, and covered by the Gluteus
maximus, and divides into branches, which supply the deep muscles at the back
of the hip.
Within the pelvis it distributes branches to the Pyriformis, Coccygeus, and
Levator ani muscles ; some hemorrhoidal branches, which supply the rectum,
and occasionally take the place of the middle hemorrhoidal artery ; and vesical
branches to the base and neck of the bladder, vesiculse seminales, and prostate
gland. External to the pelvis^ it gives off" the coccygeal, inferior gluteal, comes
nervi ischiadici, muscular, and articular branches.
The coccygeal branch runs inwards, pierces the great sacro-sciatic ligament, and
supplies the Gluteus maximus, the integument, and other structures on the back
of the coccyx.
The inferior gluteal branches^ three or four in number, supply the Gluteus
maximus muscle.
The comes nervi ischiadici is a long slender vessel, which accompanies the
great sciatic nerve for a short distance ; it then penetrates it, and runs in its sub-
stance to the lower part of the thigh.
The muscular branches supply the muscles on the back part of the hip, anasto-
mosing with the gluteal, internal and external circumflex, aud superior perfo-
rating arteries.
Some articular branches are distributed to the capsule of the hip-joint.
The llio-Lumbar Artery ascends beneath the Psoas muscle and external iliac
vessels, to the upper part of the iliac fossa, where it divides into a lumbar and
an iliac branch.
The lumbar branch supplies the Psoas and Quadratus lumborum muscles,
anastomosing with the last lumbar artery, and sends a small spinal branch
through the intervertebal foramen, between the last lumbar vertebra and the
sacrum, into the spinal canal, to supply the spinal cord and its membranes.
The iliac branch descends to supply the Iliacus internus, some offsets running
between the muscle and the bone, one of which enters an oblique canal to sup-
ply the diploe, whilst others run along the crest of the ilium, distributing
branches to the Gluteal and Abdominal muscles, and anastomosing in their
course with the gluteal, circumflex iliac, external circumflex, and epigastric
arteries.
The Lateral Sacral Arteries (Fig. 324) are usually two in number on each side,
superior and inferior.
The superior^ which is of large size, passes inwards, and, after anastomosing
with branches from the middle sacral, enters the first or second sacral foramen,
is distributed to the contents of the sacral canal, and escaping by the corre-
sponding posterior sacral foramen, supplies the skin and muscles on the dorsum
of the sacrum.
The inferior passes obliquely across the front of the Pyriformis muscle and
sacral nerves to the inner side of the anterior sacral foramina, descends on the
front of the sacrum, and anastomoses over the coccyx with the sacra media and
opposite lateral sacral arteries. In its course, it gives off branches, which enter
the anterior sacral foramina ; these, after supplying the bones and membranes
of the interior of the spinal canal, escape by the posterior sacral foramina, and
are distributed to the muscles and skin on the dorsal surface of the sacrum.
The Gluteal Artery is the largest branch of the internal iliac, and appears to
be the continuation of the posterior division of that vessel. It is a short, thick
trunk, which passes out of the pelvis above the upper border of the Pyriformis
muscle, and immediately divides into a superficial and deep branch. Within
the pelvis, it gives off a few muscular branches to the Iliacus, Pyriformis, and
Obturator internus, and just previous to quitting that cavity a nutrient artery,
which enters the ilium.
544 ARTERIES.
The superficial branch passes beneatli the Gluteus maximus, and divides into
numerous branches, some of which suj)plj that muscle, whilst others perforate
its tendinous origin, and supply the integument covering the posterior surface
of the sacrum, anastomosing with the posterior branches of the sacral arteries.
The deep branch runs betiveen the Gluteus medius and minimus, and subdivides
into two. Of these, the superior division, continuing the original course of the
vessel, passes along the upper border of the Gluteus minimus to the anterior
superior spine of the ilium, anastomosing with the circumflex iliac and ascending
branches of the external circumflex artery. The inferior division crosses the
Gluteus minimus obliquely to the trochanter major, distributing branches to
the Glutei muscles, and inosculates with the external circumflex artery. Some
branches pierce the Gluteus minimus to supply the hip-joint.
External Iliac Arteey. (Fig. 324.)
The External Iliac Artery is the chief vessel which supplies the lower limb.
It is larger in the adult than the internal iliac, and passes obliquely downwards
and outwards along the inner border of the Psoas muscle, from the bifurcation
of the common iliac to the femoral arch, where it enters the thigh, and becomes
the femoral artery. The course of this vessel would be indicated by a line drawn
from the left side of the umbilicus to a point midway between the anterior supe-
rior spinous process of the ilium and the symphysis pubis.
Relations. In front^ with the peritoneum, subperitoneal areolar tissue, the
intestines, and a thin layer of fascia, derived from the iliac fascia, which sur-
rounds the artery and vein. At its origin it is occasionally crossed by the ureter.
The spermatic vessels descend for some distance upon it near its termination,
and it is crossed in this situation by a branch of the genito-crural nerve and_
the circumflex iliac vein; the vas deferens curves down along its inner side.
Behind^ it is in relation with the external iliac vein, which, at the femoral arch,
lies at its inner side; on the left side the vein is altogether internal to the artery.
Externally^ it rests against the Psoas muscle, from which it is separated by the
iliac fascia. The artery rests upon this muscle, near Poupart's ligament.
ISTumerous lymphatic vessels and glands are found lying on the front and inner
side of the vessel.
Plax of the Relations of the External Iliac Artery.
In front.
Peritoneum, intestines, and iliac fascia.
>T^ f Spermatic A'esscls.
-p ' +> I Gi-enito-crural nerve (genital hranch).
T ■ ^ i Circumflex iliac vein.
Ligament. j t ,-■ i i i i
'^ l_ Lymphatic vessels and glands.
Outer side. / \ Inner side.
T-, / External \ ,t , i -i- • i t f
Psoas magnus iliac. i L.xternal iliac vein and vas deierena
Iliac fascia. ' \ / al femoral arch.
Behind.
E.xteriial iliac vein.
Psoas magnus.
fiurrfical Anatomy. The application of a ligature to the external iliac may lie required in
cases of aneurism of the femoral arti'ry, or in cases of secondary hemorrhage, after the latter
vessel has been tied for popliteal aneurism. 'I'his vessel maybe secured in any ]iart of its course,
excepting near its upper end, which is to he avoided on account of the proximity of the great
stream of blood in \\w internal iliac, and near its lower end, which should also be avoided, on
account of the proximity of tlm epigastric and circumflex iliac vessels. ()ne of the chief points
in the performance of the operation is to secure the vessel without injury to the peritoneum.
EXTERNAL ILIAC. 545
The patient having been placed in the recumbent position, an incision shovdd be made, com-
mencing below at a point about three-quarters of an inch above Poupart's ligament, and a little
external to its middle, and running upwards and outwards, parallel to Poupart's ligament, to a
point above the anterior superior spine of the ilium. When the artery is deeply seated, more
room will be required, and may be obtained by curving the incision from the point last named
inwards towards the umbilicus for a short distance ; or, if the lower part of the artery is to be
reached, the surgeon may commence the incision nearer the inner end of Poupart's ligament,
taking care to avoid the epigastric artery. Abernethy, who first tied this artery, made his
incision in the course of the vessel. The precise line of incision selected is of less moment, pro-
vided an easy access to the deeper parts is secured. The abdominal muscles and transversalis
fascia having been cautiously divided, the peritoneum should be separated from the iliac fossa
and pushed towards the pelvis; and on introducing the finger to the bottom of the wound the
artery may be felt pulsating along the inner border of the Psoas muscle. The external iliac
vein is generally found on the inner side of the artery, and must be cautiously separated from it
by the finger-nail, or handle of the knife, and the aneurism needle should be introduced on the
inner side, between the artery and vein.
Collateral Circulation. The principal anastomoses in carrying on the collateral circulation,
after the application of a ligature to the external iliac, are — the ilio-lumbar with the circumflex
iliac; the gluteal with the external circumflex; the obturator with the internal circumflex; the
sciatic with the superior perforating and circumflex branches of the profunda artery; the internal
pudic with the external pudic, and with the internal circumflex. When the obturator arises from
the epigastric, it is supplied with blood by branches, either from the internal iliac, the lateral
sacral, or the internal pudic. The epigastric receives its supply from the internal mammary and
inferior intercostal arteries, and from the internal iliac, by the anastomoses of its branches with
the obturator.
In the dissection of a limb, eighteen years after the successful ligature of the external iliac
artery, by Sir A. Cooper, which is to be found in Guy's Hospital Eeports, vol. 1. p. 50, <Jhe
anastomosing branches are described in three sets. An anterior set. 1. A very large branch
from the ilio-lumbar artery to the circumflex iliac ; 2. Another branch from the ilio-lumbar,
joined by one from the obturator, and breaking up into numerous tortuous branches to anasto-
mose with the external circumflex ; 3. Two other branches from the obturator, which passed
over the brim of the pelvis, communicated with the epigastric, and then broke up into a plexus
to anastomose with the internal circumflex. An internal set. Branches given off from the
obturator, after quitting the pelvis, which ramified among the adductor muscles on the inner
side of the hip-joint, and joined most freely with branches of the internal circumflex. A posterior
set. 1. Three large branches from the gluteal to the external circumflex : 2. Several branches
from the sciatic around the great sciatic notch to the internal and external circumflex, and the
perforating branches of the profunda.
Branches. Besides several small brandies to tlie Psoas muscles and tlie
neigliboring lymphatic glands, the external iliac gives off two branches of
considerable size, the
Epigastric and Circumflex iliac.
The Einyastric artery arises from the external iliac, a few lines above Pou-
part's ligament. It at first descends to reach this ligament, and then ascends
obliquely inwards between the peritoneum and transversalis fascia, to the
margin of the sheath of the Pectus muscle. Having perforated the sheath near
its lower third, it runs vertically upwards behind the Pectus, to which it is
distributed, dividing into numerous branches, which anastomose above the
umbilicus with the terminal branches of the internal mammary and inferior
intercostal arteries. It is accompanied by two veins, which usually unite into
a single trunk before their termination in the external iliac vein. As this
artery ascends from Poupart's ligament to the Pectus, it lies behind the inguinal
canal, to the inner side of the internal abdominal ring, and immediately above
the femoral ring. The vas deferens in the male, and the round ligament in the
female, cross behind the artery in descending into the pelvis.
Branches. The branches of this vessel are the following : the cremasteric^
which accompanies the spermatic cord, and supplies the Cremaster muscle,
anastomosing with the spermatic artery ; a puhic branch.^ which runs across
Poupart's ligament, and then descends behind the pubes to the inner side of the
femoral ring, and anastomoses with offsets from the obturator artery ; muscular
branches., some of which are distributed to the abdominal muscles and^eritoneum,
35
546 ARTERIES.
anastomosing with the lumbar and circumflex iliac arteries : others perforate
the tendon of the External oblique and supply the integument, anastomosing
with branches of the external epigastric.
Peculiarities. The origin of the epigastric may take place from any part of the external iliac
between Poupart's ligament and two inches and a half above it ; or it may arise below this liga-
ment, from the femoral, or from the deep femoral.
Union rvitli Branches. It frequently arises from the external iliac, by a common trunk with
the obturator. Sometimes the epigastric arises from the obturator, the latter vessel being
furnished by the internal iliac, or the epigastric may be formed of two branches, one derived from
the external iliac, the other from the internal iliac.
The circumflex iliac artery arises from the outer side of the external iliac
nearly opposite the epigastric artery. It ascends obliquely outwards behind
Poupart's ligament, and runs along the inner surface of the crest of the ilium to
about its middle, where it pierces the Transversalis, and runs backwards between
that muscle and the Internal oblique, to anastomose with the ilio-lumbar and
gluteal arteries. Opposite the anterior superior spine of the ilium, it gives off"
a large branch, which ascends between the internal oblique and Transversalis
muscles, supplying them and anastomosing with the lumbar and epigastric
arteries. The circumflex iliac artery is accompanied by two veins. These
unite into a single trunk which crosses the external iliac artery just above Pou-
part's ligament, and enters the external iliac vein.
Pemoeal Artery. (Fig. 328.)
The Femoral Artery is the continuation of the external iliac. It commences
immediately behind Poupart's ligament, midway between the anterior superior
spine of the ilium and the symphysis pubis, and passing down the fore part and
inner side of the thigh, terminates at the opening in the Adductor magnus, at
the junction of the middle with the lower third of the thigh, where it becomes
the popliteal artery. A line drawn from a point midway between the anterior
superior spine of the ilium and the symphysis pu.bis to the inner side of the inner
condyle of the femur, will be nearly parallel with the course of the artery. • This
vessel, at the upper part of the thigh, lies a little internal to the head of the
femur ; in the lower part of its course, on the inner side of the shaft of the bone,
and between these two parts, the vessel is far away from the bone.
In the U2oper third of the thigh the femoral artery is very superficial, being-
covered by the integument, inguinal glands, and the superficial and deep fasciae,
and is contained in a triangular space, called "Scarpa's triangle."
Scarpa's triangle. Scarpa's triangle corresponds to the depression seen imme-
diately below the fold of the groin. It is a triangular space, the apex of which
is directed dowuAvards, and the sides of which are formed externally by the
Sartorius, internally by the Adductor longus, and above by Poupart's ligament.
The floor of this space is formed from without inwards by the Iliacus, Psoas,
Pectineus, Adductor longus, and a small part of the Adductor brevis muscles ;
and it is divided into two nearly equal parts by the femoral vessels, which
extend from tlie middle of its base to its apex ; the artery giving off' in this situa-
tion its cutaneous and profunda branches, the vein receiving the deep femoral
and internal saphenous veins. In this space the femoral artery resfs on the
inner margin of the psoas muscle, which separates it from the capsular ligament
of the hip-joint. The artery in this situation has in front of it filaments from
the crural branch of the genito-crural nerve, and branches from the anterior
crural, one of which is usually of considerable size; behind the artery is the
branch to tlie Pectineus from the anterior crirral. The femoral vein lies at its
inner side, between the margins of the Pectineus and Psoas muscles. The ante-
rior crural nerve lies about half an inch to the outer side of the ffnnoral artery,
deeply imbedded between the Iliacus and Psoas muscles. The femoral artery
FEMORAL.
547
Surgical Anatomy of tlie Femoral Artery.
and vein are inclosed in a
strong fibrous slieatli formed
by fibrons and cellular tissue,
and by a process of fascia sent
inwards, from tbe fascia lata ;
tb.e vessels are separated, how-
ever, from one another by thin
fibrous partitions.
In the middle third of the
thigh^ the femoral artery is
more deeply seated, being
covered by the integument,
the superficial and deep fascia,
and the Sartorius, and is con-
tained in an aponeurotic canal
(Hunter's canal), formed by a
dense fibrous band, which ex-
tends transversely from the
Vastus internus to the tendons
of the Adductor longus and
magnus muscles. In this part
of its course it' lies in a de-
pression, bounded externally
by the Vastus internus, inter-
nally by the Adductor longus
and Adductor magnus. The
femoral vein lies on the outer
side of the artery, in close
apposition with it, and, still
more externally, is the inter-
nal (long) saphenous nerve.
Relations. From above down-
zvards, the femoral artery rests
upon the Psoas muscle, which
separates it from the margin
of the pelvis and capsular
ligament of the hip ; it is next
separated from the Pectineus
by the profunda vessels and
femoral veins ; it then lies
upon the Adductor longus ;
and lastly, upon the tendon of
the Adductor magnus, the
femoral vein being interposed.
To its inner side, it is in rela-
tion above, with the femoral
vein, and lower down, with the Adductor longus, and Sartorius. To its outer
side, the Vastus internus separates it from the femur, in the lower part of its
course.
The femoral vein, at Poupart's ligament, lies close to the inner side of the
artery, separated from it by a thin fibrous partition, but, as it descends, gets be-
hind it, and then to its outer side.
The Internal saphenous nerve is situated on the outer side of the artery, in the
middle third of the thigh, beneath the aponeurotic covering, but not usually
within the sheath of the vessels. Small cutaneous nerves cross the front of the
sheath.
Stcper. E.
InJiV, Moifarvtil Artto.
Anter. Tibial Xscarr^a-f-
•l!,/^.JLt^=-Ml Artie ?■
548
ARTERIES.
PlajSt of the Eelatioxs of the Femoral Aetery.
In front.
Fascia lata.
Branch of anterior crural nerve.
Sartorius.
Long saphenous nerve.
Aponeurotic covering of Hunter's canal.
Inner side.
Femoral vein (at upper part).
Adductor longus.
Sartorius.
Outer side.
Vastus intern us.
Femoral vein (at lower part)
Behind.
Psoas muscle.
Profunda vein.
Pectineus muscle.
Adductor longus.
Femoral vein.
Adductor magnus.
Pecidiarities. Doulle femoral reunited. Four cases are at present recorded, in which the
femoral artery divided into two trunks below the origin of the profunda, and became reunited
uear the opening in the Adductor maguus, so as to form a single popliteal artery. One of them
occurred in a patient operated upon for popliteal aneurism.
Change of Position. A similar number of cases have been recorded, in which the femoral
artery was situated at the back of the thigh, the vessel being continuous above with the internal
iliac, escaping from the pelvis through the great sacro-sciatic foramen, and accompanying the
great sciatic nerve to the popliteal space, where its division occurred in the usual manner.
Position of the Vein. The femoral vein is occasionally placed along the inner side of the
artery, throughout the entire extent of Scarpa's triangle ; or it may be slit, so that a large vein
is placed on each side of the artery for a greater or less extent.
Origin of the Profunda. This vessel occasionally arises from the inner side, and more rarely,
from the back of the common trunk ; but the more important peculiarity, in a surgical point of
view, is that which relates to the height at which the vessel arises from the femoral. In three-
fourths of a large number of cases, it arose between one and two inches below Poupart's ligament ;
in a few cases, the distance was less than an inch ; more rarely, opposite the ligament ; and in one
case, above Poupart's ligament, from the external iliac. Occasionally, the distance between the
origin of the vessel and Poupart's ligament exceeds two inches, and in one case it was found to
be as much as four inches.
Surgical Anatomy. Compression of the femoral artery, which is constantly requisite in
amputations and other operations on the lower limb, is most effectually made immediately below
Poupart's ligament. In this situation the artery is very superficial, and is merely separated from
the margin of the acetabulum and front of the head of the femur, by the Psoas muscle ; so that
the surgeon, by means of his thumb, or a compresser, may effectually control the circulation
through it. This vessel may also be compressed in the middle third of the thigh, by placing a
compress over the artery, beneath the tourniquet, and directing the pressure from within outwards
so as to compress the vessel against the inner side of the shaft of the femur.
'J'hc application of a ligature to the femoral artery may be required in cases of wound or
aneurism of the arteries of the leg, of the popliteal or femoral ; and the vessel may be exposed
and tied in any part of its course. The great depth of this vessel at its lower part, its close
connection with important structures, and the density of its sheath, render the operation in this
situation one of much greater difficulty than the application of a ligature at its upper part, where
it is more superficial.
liigature of the femoral artery, within two inches of its origin, is usually considered unsafe, on
account of the connection of large branches with it, the C]iigastric and circumflex iliac arising
just above its origin ; the profunda, from one to two inches ix.'low; occasionally, also, one of the
circumflex arteries arises from the vessel in the intersjiace between these. 'I'he ])r()funda sometimes
arises higher than the point above mcMitioneil, and rarely between two and three inches (in one case
four) below Poupart's ligament. It would appear, then, that the most favoralile situation for the
application of a ligature to the femoral, is between four and five inches froni its point of origin. In
onier to expose the artery in this situation, an incision, between two and three inches long, should
be made in the course of the vessel, the patient lying in the recuml)ent position, with the limb
slightly flexed and al>dtictcd. A large vein is freciuently met with, i)assing in the course of the
artery to join the saphena ; this must be avoided, and the fascia lata having been cautiously
divided, and the Sartorius exposed, that muscle must be drawn outwards, in order to fully expose
FEMORAL. 549
the sheath of the vessels. The finger being introduced into the wound, and the pulsation of the
artery felt, the sheath should be divided over the artery to a sufficient extent to allow of the
introduction of the ligature, but no further; otherwise the nutrition of the coats of the vessel
may be interfered with, or muscular branches which arise from the vessel at irregular intervals
may be divided. In this part of the operation, a small nerve which crosses the sheath should be
avoided. The aneurism needle must be carefully introduced and kept close to the artery, to avoid
the femoral vein, which lies behind the vessel in this part of its course.
. To expose the artery in the middle of the thigh, an incision should be made through the in-
tegument, between three and four inches in length, over the inner margin of the Sartorius, taking
care to avoid the internal saphenous vein, the situation of which may be previously known by
compressing it higher up in the thigh. The fascia lata having been divided, and the Sartorius
muscle exposed, it should be drawn outwards, when the strong fascia which is stretched across
from the Adductors to the Vastus internus, will be exposed, and must be freely divided ; the
sheath of the vessels is now seen, and must be opened, and the artery secured by passing the
aneurism needle between the vein and artery, in the direction from within outwards. The femoral
vein in this situation lies on the outer side of the artery, the long saphenous nerve on its anterior
and outer side.
It has been seen that the femoral artery occasionally divides into two trunks, below the origin
of the profunda. If, in the operation for tying the femoral, two vessels are met with, the surgeon
should alternately compress each, in order to ascertain which vessel is connected with the aneu-
rismal tumor, or with the bleeding from the wound, and that one only should be tied which con-
trols the pulsation or hemorrhage. If, however, it is necessary to compress both vessels before
the circulation in the tumor is controlled, both should be tied, as it would be probable that they
became re-united, as in the four instances referred to above.
Collateral Circulation. When the common femoral is tied, the main channels for carrying on
the circulation are the anastomoses of the gluteal and circumflex iliac arteries above with the
external circumflex below ; of the obturator and sciatic above with the internal circumflex below ;
of the ilio-lumbar with the external circumflex, and of the comes nervi ischiadici with the arteries
in the ham.
The principal agents in carrying on the collateral circulation after ligature of the superficial
femoral artery are, according to Sir A. Cooper, as follows.'
" The arteria profunda formed the new channel for the blood. The first artery sent off passed
down close to the back of the thigh bone, and entered the two superior articular branches of the
popliteal artery.
'' The second new large vessel arising from the profunda at the same part with the former,
passed down by the inner side of the Biceps muscle, to an artery of the popliteal which was dis-
tributed to the Gastrocnemius muscle ; whilst a third artery dividing into several branches passed
down with the sciatic nerve behind the knee-joint, and some of its branches united themselves
with the inferior articular arteries of the popliteal, with some recurrent branches of those arteries,
with arteries passing to the Gastrocnemii, and, lastly, with the origin of the anterior and postei'ior
tibial arteries.
" It appears then that it is those branches of the profunda which accompany the sciatic nerve
that are the principal supporters of the new circulation."
In Porta's^ work (Tab. xii. xiii.) is a good representation of the collateral circulation after the
ligature of the femoral artery. The patient had survived the operation three years. The lower
part of the artery is, at least, as large as the upper ; about two inches of the vessel appear to have
been obliterated. The external and internal circumflex arteries are seen anastomosing by a great
number of branches with the lower branches of the femoral (muscular and anastomotica magna),
and with the articular branches of the popliteal. The branches from the external circumflex are
extremely large and numerous, one very distinct anastomosis can be traced between this artery
on the outside, and the anastomotica magna on the inside, through the intervention of the superior
external articular artery with which they both anastomose, and blood reaches even the anterior
tibial recurrent from the external circumflex by means of an anastomosis with the same external
articular artery. The perforating branches of the profunda are also seen bringing blood round the
obliterated portion of the artery into long branches (muscular) which have been given off just
below that portion. The termination of the profunda itself anastomoses most freely with the
superior external articular. A long branch of anastomosis is also traced down from the internal
iliac by means of the comes nervi ischiadici of the sciatic which anastomoses on the popliteal nerves
with branches from the popliteal and posterior tibial arteries. In this case the anastomosis had
been too free, since the pulsation and growth of the aneurism recurred, and the patient died after
ligature of the external iliac.
There is an interesting preparation in the Museum of the Royal College of Surgeons, of a limb
on which John Hunter had tied the femoral artery fifty years before the patient's death. The
whole of the superficial femoral and popliteal artery seems to have been obliterated. The anasto-
mosis by means of the comes nervi ischiadici, which is shown in Porta's plate, is distinctly seen ;
the external circumflex, and the termination of the profunda artery, seem to have been the chief
channels of anastomosis ; but the injection has not been a very successful one.
' Med.-Cliir. Trans., vol. ii. 1811. ^ Alterazioni jpatologiche delle Arterie.
550 AETERIES.
Branches. Tlie branclies of tlie femoral artery are the
Superficial epigastric.
Superficial circumflex iliac.
Superficial external pudic.
Deep external pudic.
i External circumflex.
Profunda. I Internal circumflex.
( Three perforating.
Muscular.
Anastomotica magna.
The superficial epigastric arises from the femoral, about half an inch below
Poupart's ligament, and, passing through the saphenous opening in the fascia
lata, ascends on to the abdomen, in the superficial fascia covering the external
oblique muscle, nearly as high as the umbilicus. It distributes branches to the
inguinal glands, the superficial fascia and the integument, anastomosing with
branches of the deep epigastric and internal mammary arteries.
The superficial circur)%flex iliac^ the smallest of the cutaneous branches, arises
close to the preceding, and, piercing the fascia lata, runs outwards, parallel with
Poupart's ligament, as far as the crest of the ilium, dividing into branches which
supply the integument of the groin, the superficial fascia, and inguinal glands,
anastomosing with the circumflex iliac, and with the gluteal and external cicum-
flex arteries.
The superficial external pudic (superior) arises from the inner side of the
femoral artery, close to the preceding vessels, and, after piercing the fascia lata
at the saphenous opening, passes inwards, across the spermatic cord, to be dis-
tributed to the integument on the lower part of the abdomen, the penis and
scrotum in the male, and the labium in the female, anastomosing with branches
of the internal pudic.
The deep external pudic (inferior), more deeply seated than the preceding,
passes inwards on the Pectineus muscle, covered by the fascia lata, which it
pierces opposite the ramus of the pubes, its branches being distributed, in the
male, to the integument of the scrotum and perineum, and in the female, to the
labium, anastomosing with branches of the superficial perineal artery.
The Profunda Femoris (deep femoral artery) nearly equals the size of the
superficial femoral. It arises from the outer and back part of the femoral artery,
from one to two inches below Poupart's ligament. It at first lies on the outer
side of the superficial femoral, and then passes behind it and the femoral vein
to the inner side of the femur, and terminates at the lower third of the thigh in
a small branch, which pierces the Adductor magnus (and from this circumstance
is sometimes called the fourth perforating artery), to be distributed to the flexor
muscles on the back of the thigh, anastomosing with branches of the popliteal
and inferior perforating arteries.
Relations. Behind^ it lies first upon the iliacus, and then on the Adductor
brevis and Adductor magnus muscles. In front^ it is separated from the femoral
artery, above by the femoral and profunda veins, and below by the Adductor
longus. On its outer side^ the origin of the Vastus intcruus separates it from the
femur.
PROFUNDA FEMORIS. 551
Plan of the Eelations of the Profunda Arteey.
In front.
Femoral and profunda veins.
Adductor longus.
Outer side.
Yastus internus.
Belvind.
Iliacus.
Adductor brevis.
Adductor maguus.
Tlie External Circumflex Artery supplies the muscles on tlie front of the tliigh.
It arises from the outer side of the profunda, passes horizontally outwards,
between the divisions of the anterior crural nerve, and behind the Sartorius and
Pectus muscles, and divides into three sets of branches, ascending, transverse,
and descending.
The ascending hranches pass upwards, beneath the Tensor vaginas femoris
muscle, to the outer side of the hip, anastomosing with the terminal branches
of the gluteal and circumflex iliac arteries.
The descending branches., three or four in number, pass downwards, behind the
rectus, upon the Yasti muscles, to which they are distributed, one or two passing
beneath the Yastus externus as far as the knee, anastomosing with the superior
articular branches of the popliteal artery.
The transverse branches^ the smallest and least numerous, pass outwards over
the Crurgeus, pierce the Yastus externus, and wind round the femur to its back
part, just below the great trochanter, anastomosing at the back of the thigh
with the internal circumflex, sciatic, and superior perforating arteries.
The Internal Circumflex Artery., smaller than the external, arises from the
inner and back part of the profunda, and winds round the inner side of the
femur, between the Pectineus and Psoas muscles. On reaching the tendon of
the Obturator externus, it gives off two branches, one of which passes inwards
to be distributed to the Adductor muscles, the Grracilis, and Obturator externus,
anastomosing with the obturator artery ; the other descends, and passes beneath
the Adductor brevis, to supply it and the great Adductor ; while the continua-
tion of the vessel passes backwards, between the Quadratus femoris and uj)per
border of the Adductor magnus, anastomosing with the sciatic, external circum-
flex, and superior perforating arteries. Opposite the hip-joint, this branch gives
off an articular vessel, which enters the joint beneath the transverse ligament ;
and after supplying the adipose tissue, passes along the round ligament to the
head of the bone.
The Perforating Arteries (Fig. 327), usually three in number, are so called
from their perforating the tendons of the Adductor brevis and magnus muscles
to reach the back of the thigh. The first is given off above the Adductor brevis,
the second in front of that muscle, and the third immediately below it.
'Yhe first or superior perforating artery passes backwards between the Pectineus
and Adductor brevis (sometimes perforates the latter) ; it then pierces the Adduc-
tor magnus close to the linea aspera, and divides into branches which supply
both Adductors, the Biceps, and Gluteus maxim us muscle ; anastomosing with
the sciatic, internal circumflex, and middle perforating arteries.
The second or middle perforating artery ., larger than the first, pierces the ten-
dons of the Adductor brevis and Adductor magnus muscles, and divides into
ascending and descending branches, which supply the flexor muscles of the
552 ARTERIES.
tliigli, anastomosing witli tlie superior and inferior perforating. The nutrient
artery of the femur is usually given off from this branch.
The third or inferior perforating artery is given off below the Adductor
brevis; it pierces the Adductor magnus, and divides into branches which supply
the flexor muscles of the thigh; anastomosing with the perforating arteries
above, and with the terminal branches of the profunda below.
Muscular Branches are given off' from the superficial femoral throughout its
entire course. They vary from two to seven in number, and supply chiefly the
Sartorius and Vastus internus.
The Anastomotica Magna arises from the femoral artery just before it passes
through the tendinous opening in the Adductor magnus muscles, and divides
into a superficial and deep branch.
The superficial branch accompanies the long saphenous nerve, beneath the
Sartorius, and, piercing the fascia lata, is distributed to the integument.
The deep branch descends in the substance of the Vastus internus, lying in
front of the tendon of the Adductor magnus, to the inner side of the knee,
where it anastomoses with the superior internal articular artery and recurrent
branch of the anterior tibial. A branch from this vessel crosses outwards above
the articular surface of the femur, forming an anastomotic arch with the supe-
rior external articular artery, and supplies branches to the knee-joint.
Popliteal Artery.
The Popliteal Artery commences at the termination of the femoral at the
opening in the Adductor magnus, and, passing obliquely downwards and out-
wards behind the knee-joint to the lower border of the Popliteus muscle, divides
into the anterior and posterior tibial arteries. Through the whole of this extent
the artery lies in the popliteal space.
The Popliteal Space. (Fig. 329.)
Dissection. A vertical incision about eight inches in length should be made along the back
part of the knee-joint, connected above and below by a transverse incision from the inner to the
outer side of the limb. The flaps of integument included between these incisions should be re-
flected in the direction shown in fig. 286, p. 440.
On removing the integument, the superficial fascia is exposed, and ramifying
in it along the middle line are found some filaments of the small sciatic nerve,
and towards the inner part some offsets from the internal cutaneous nerve.
The superficial fascia having been removed, the fascia lata is brought into
view. In this region it is strong and dense, being strengthened by transverse
fibres, and firmly attached to the tendons on the inner and outer sides of the
space. It is perforated below by the external saphenous vein. This fascia
having been reflected back in the same direction as the integument, the small
sciatic nerve and external saphenous vein are seen immediately beneath it, in
the middle line. If the loose adipose tissue is now removed, the boundaries
and contents of the space may be examined.
Bovrndaries. The popliteal space, or the ham, occupies the lower third of the
thigh and the upper fifth of the leg; extending from the aperture in the Ad-
ductor magnus to the lower border of the Popliteus muscle. It is a lozenge-
shaped space, being widest at the back part of the knee-joint, and deepest above
the articular end of the femur. It is bounded, externally, above the joint, by
the Biceps, and below the joint by the Plantaris and external head of the Gas-
trocnemius. Internally, above the joint, by the Semimembranosus, Scmitendi-
noRus, Gracilis, and Sartorius; below the joint, by the inner liead of the Gastro-
cnemius.
Above, it is limited by the apposition of the inner nnd outer hamstring
muscles; below, by the junction of the two heads of the Gastrocnemius. The
floor is formed by the lower part of the posterior surface of the shaft of the
POPLITEAL. 553
femur, the posterior ligament of the kuee-joint, the upper end of the tibia, and
the fascia covering the Popliteus muscle, and the space is covered in by the
fascia lata.
Contents. It contains the Popliteal vessels and their branches, together with
the termination of the external saphenous vein, the internal and external popli-
teal nerves and their branches, the small sciatic nerve, the articular branch from
the obturator nerve, a few small lymphatic glands, and a considerable quantity
of loose adipose tissue.
Position of contained parts. The internal popliteal nerve descends in the
middle line of the space, lying superficial and a little external to the vein and
artery. The external popliteal nerve descends on the outer side of the space,
lying close to the tendon of the Biceps muscle. More deeply at the bottom of
the space are the popliteal vessels, the vein lying superficial and a little exter-
nal to the artery, to which it is closely united by dense areolar tissue ; sometimes
the vein is placed on the inner instead of the outer side of the artery ; or the
vein may be double, the artery lying between the two ven« comites, which are
usually connected by short transverse branches. More deeply, and close to the
surface of the bone, is the popliteal artery, and passing off from it at right
angles are its articular branches. The articular branch from the obturator
nerve descends upon the popliteal artery to supply the knee; and occasionally
there is found deep in the space an articular filament from the great sciatic
nerve. The popliteal lymphatic glands, four or five in number, are found sur-
rounding the artery; one usually lies superficial to the vessel, another is situated
between it and the bone, and the rest are placed on either side of it. The bursje
usually found in this space are: 1. On the outer side, one beneath the outer
head of the Gastrocnemius (which sometimes communicates with the joint) and
one beneath the tendon of the Popliteus, which is almost always an extension
of the synovial membrane. Sometimes also there is a bursa above the tendon
of the Popliteus, between it and the external lateral ligament. 2. On the inner
side of the joint there is a large bursa between the inner head of the Grastro-
cnemius and the femur, which sends a prolongation between the tendons of the
Gastrocnemius and Semimembranosus, and lies in contact with the ligament of
Winslow. This bursa often communicates with the joint. There is a second
bursa between the tendon of the Semimembranosus and the head of the tibia ;
and sometimes a bursa between the tendons of the Semitendinosus and Semi-
membranosus.
The Popliteal Artery, in its course downwards from the aperture in the
Adductor magnus to the lower border of the Popliteus muscle, rests first on the
inner, and then on the posterior surface of the femur ; in the middle of its course,
on the posterior ligament of the knee-joint; and below, on the fascia covering
the Popliteus muscle. Superficially^ it is covered, above, by the Semimembra-
nosus ; in the middle of its course, by a quantity of fat, which separates it from
the deep fascia and integument ; and below, it is overlapped by the Gastro-
cnemius, Plantaris, and Soleus muscles, the popliteal vein, and the internal popli-
^teal nerve. The popliteal vein, which is intimately attached to the artery, lies
superficial and external to it, until near its termination, when it crosses it and
lies to its inner side. The popliteal nerve is still more superficial and external,
crossing, however, the artery below the joint, and lying on its inner side.
Laterally^ the artery is bounded by the muscles which form the boundaries of
the popliteal space.
Peculiarities in point of division. Occasionally the popliteal artery divides prematurely into
its terminal branches; this division occurs most frequently opposite the knee-joint.
Unusual hranclies. The artery sometimes divides into the anterior tibial and peroneal,. the
posterior tibial being wanting, or very small. In a single case, the popliteal was found to divide
into three branches, the anterior and posterior tibial, and peroneal.
Surgical Anatomy. Ligature of the popliteal artery is required in cases of wound of that
vessel, but for aneurism of the posterior tibial it is preferable to tie the superficial femoral. The
popliteal may be tied in the upper or lower part of its course ; but in the middle of the ham the
554 ARTERIES.
operation is attended with considerable difficulty, from the great depth of the artery, and from
the extreme degree of tension of the lateral boundaries of the space.
In order to expose the vessel in the upper part of its course, the patient should he placed in
the prone position, with the limb extended. An incision about three inches in length should then
be made through the integument, along the posterior margin of the Semimembranosus, and the
fascia lata having been divided, this muscle must be drawn inwards, when the pulsation of the
vessel will be detected with the finger ; the nerve lies on the outer or fibular side of the artery,
the vein, superficial and also to its outer side ; the vein having been cautiously separated from
the artery, the aneurism needle should be passed around the latter vessel from without inwards.
To expose the vessel in the lower part of its course, where the artery lies between the two
heads of the Gastrocnemius, the patient should be placed in the same position as in the preceding
operation. An incision should then be made through the integument in the middle line, com-
mencing opposite the bend of the knee-joint, care being taken to avoid the external saphenous vein
and nerve. After dividing the deep fascia, and separating some dense cellular membrane, the
artery, vein, and nerve will be exposed, descending between the two heads of the Gastrocnemius.
Borne muscular branches of the popliteal should be avoided if possible, or if divided, tied imme-
diately. The leg being now flexed, in order the more effectually to separate the two heads of
the Gastrocnemius, the nerve should be drawn inwards and the vein outwards, and the aneurism
needle passed between the artery and vein from without inwards.
Plan of Eelations of Popliteal Artery.
In front.
Femur.
Ligamentum posticum.
Popliteus.
Inner side. I poputeal \ Outer side.
Semimembranosus. I Aiteiy. y Biceps.
Behind.
Popliteal vein.
Internal popliteal nerve.
Fascia.
The branches of the popliteal artery are, the
T,r 1 ( Superior,
Muscular i t i • a i
( interior or bural.
Cutaneous.
Superior external articu.lar.
Superior internal articular.
Azygos articular.
Inferior external articular.
Inferior internal articular.
The superior muscvJar branches, two or three in number, arise from the upper
part of the popliteal artery, and are distributed to the Vastus externus and
flexor muscles of the thigh ; anastomosing with the inferior perforating, and
terminal branches of the profunda.
The inferior muscular {Sural) are two large branches, which are distributed
to the two heads of the Grastrocnemius and to the Pkmtaris muscle. They arise
from the popliteal artery opposite the knee-joint.
Cutaneous hranches descend on each side and in the middle of tlic limb, be-
tween the Gastrocnemius and integument ; they arise separately from the
popliteal artery, or from some of its branches, and supply the integument of the
calf.
Tlie superior a.rlicular arteries, two in number, arise one on either side of the
popliteal, and wind round tlie femur immediately above its condyles to the front
of the knee-joint. The internal branch passes beneath the tendon of the Adduc-
tor magnu.s, and divides into two, one of which supplies the Vastus intcrnus.
ANTEEIOR TIBIAL. 555
inosculating with the anastomotica magna and inferior internal articular ; the
other ramifies close to the surface of the femur, supplying it and the knee-joint,
and anastomosing with the superior external articular artery. The external
hranch passes above the outer condyle, beneath the tendon of the Biceps, and
divides into a superficial and deep branch : the superficial branch supplies the
Vastus externus, and anastomoses with the descending branch of the external
circumflex artery ; the deep branch supplies the lower part of the femur and
knee-joint, and forms an anastomotic arch across the bone with the anastomo-
tica magna artery.
The azygos articular is a small branch, arising from the popliteal artery oppo-
site the bend of the knee-joint. It pierces the posterior ligament, and supplies
the ligaments and synovial membrane in the interior of the articulation.
The inferior articular arteries^ two in number, arise from the popliteal beneath
the Gastrocnemius, and wind round the head of the tibia, below the joint. The
internal one passes below the inner tuberosity, beneath the internal lateral liga-
ment, at the anterior border of which it ascends to the front and inner side of
the joint, to supply the head of the tibia and the articulation of the knee. The
external one passes outwards above the head of the fibula, to the front of the
knee-joint, lying in its course beneath the outer head of the Grastrocnemius, the
external lateral ligament, and the tendon of the Biceps muscle, and divides into
branches, which anastomose with the inferior internal articular artery, the supe-
rior articular arteries, and the recurrent branch of the anterior tibial.
Anterior Tibial Artery. (Fig. 330.)
The Anterior Tibial Artery commences at the bifurcation of the popliteal, at
the lower border of the Popliteus muscle, passes forwards between the two
heads of the Tibialis posticus, and through the aperture left between the bones
at the upper part of the interosseous membrane, to the deep part of the front
of the leg; it then descends on the anterior surface of the interosseous mem-
brane, and of the tibia, to the front of the ankle-joint, where it lies more super-
ficially, and becomes the dorsalis pedis. A line drawn from the inner side of_
the head of the fibula to midway between the two malleoli will mark the course
of the artery.
Relations. In the upper two-thirds of its extent, it rests upon the interosseous
membrane, to which it is connected by delicate fibrous arches thrown across it.
In the lower third, upon the front of the tibia, and the anterior ligament of the
ankle-joint. In the upper third of its course, it lies between the Tibialis anticus
and Extensor lona-us digitorum : in the middle third, between the Tibialis anti-
cus and Extensor proprius pollicis. In the lower third, it is crossed by the
tendon of the Extensor proprius pollicis, and lies between it and the innermost
tendon of the Extensor longus digitorum. It is covered, in the upper two-thirds
of its course, by the muscles which lie on either side of it, and by the deep
fascia; in the lower third, by the integument, annular ligament, and fascia.
The anterior tibial artery is accompanied by two veins (venas comites), which
lie one on either side of the artery ; the anterior tibial nerve lies at first to its
outer side, and about the middle of the leg is placed superficial to it; at the
lower part of the artery the nerve is generally again on the outer side.
556
ARTERIES.
Plan of the Eelations of the Ajstterior Tibial Artery.
In front.
Integument, superficial and deep fascite.
Tibialis anticus (overlaps it in upper part of leg).
Extensor longus digitorum ] , , -j. t uii \
T7I + • IT • t (overlap it slightly).
Extensor propnus pollicis J ^ ^ o j i
Anterior tibial nerve.
Inner side.
Tibialis anticus.
Extensor proprius pollicis
(crosses it at its lower
part).
Outer side.
Anterior tibial nerve.
Extensor longus digitorum.
Extensor proprius pollicis.
Behind.
Interosseous membrane.
Tibia.
Anterior ligament of ankle-joint.
Pecidiarities in Size. This vessel may be diminished in size, may be deficient to a greater or
less extent, or may be entirely wanting, its place being supplied by perforating branches from
the posterior tibial, or by the anterior division of the peroneal artery.
Course. The artery occasionally deviates in its course towards the fibular side of the leg,
regaining its usual position beneath the annular ligament at the front of the ankle. In two
instances, the vessel has been found to approach the surface in the middle of the leg, being covered
merely by the integument and fascia below that point.
Surgical Anatomy. The anterior tibial artery maybe tied in the upper or lower part of the
leg. In the upper part, the operation is attended with great difficulty, on account of the depth
of the vessel from the surface. An incision, about four inches in length, should be made through
the integument, midway between the spine of the tibia and the outer margin of the fibula, the
fascia and intermuscular septum between the Tibialis anticus and Extensor longus digitorum
being divided to the same extent. The foot must be flexed to relax these muscles, and they must
be separated from each other by the finger. The artery is then exposed, deeply seated, lying
upon the interosseous membrane, the nerve lying externally, and one of the venae comites on
either side ; these must be separated from the artery before the aneurism needle is passed round it.
To tie the vessel in the lower third of the leg above the ankle-joint, an incision about three
inches in length should be made through the integument between the tendons of the Tibialis
anticus and Extensor proprius pollicis muscles, the deep fascia being divided to the same extent;
the tendon on either side should be held aside, when the vessel will be seen lying upon the tibia, with
the nerve superficial to it, and one of the venae comites on either side.
In order to secure the artery over the instep, an incision should be made on the fibular side of
the tendon of the Extensor proprius pollicis, between it and the innermost tendon of the long
Extensor; the deep fascia having been divided, the artery will be exposed, the nerve lying either
superficial to it, or to its outer side.
The branclies of the anterior tibial artery are, the
Eecurrent tibial. Internal malleolar.
Muscular. External malleolar.
The recurrent hranch arises from the anterior tibial, as soon as that vessel has
passed through the interosseous space ; it ascends in the Tibialis anticus muscle,
and ramifies on the front and sides of the knee-joint, anastomosing with the
articular branches of the popliteal.
The muscular hranches are numerous ; they are distributed to the muscles
which lie on either side of the vessel, some piercing the deep fascia to sup23ly
the integument, others passing through the interosseous membrane, and anasto-
mosing with branches of the posterior tibial and peroneal arteries.
The malleolar arteries supply the ankle-joint. The internal arises about two
inches above the articulaticm, and passes beneath the tendon of the Tibialis
anticus to the inner ankle, upon which it ramifies, anastomosing with branches
of the posterior llbiiil and internal plantar arteries. The external passes
beneath the tendons of the Extensor longus digitorum and Extensor proprius
pollicis, and supplies the outer ankle, anastomosing with the anterior peroneal
artery, and with ascending branches from the tarsal branch of the dorsalis pedis.
DORSALIS PEDIS.
557
DoESALis Pedis Arteey. (Fig. 330.)
The Dorsalis Pedis, tTie continuation of tlie anterior tibial, passes forwards from
the bend of the ankle along the tibial side of the foot to the back part of the
Fig. 329. — The Popliteal, Posterior Tibial, Fig. 330. — Surgical Anatomy of the Anterior
and Peroneal Arteries.
Tibial and Dorsalis Pedis Arteries.
^\^
-Ani£TioT Peronea*
Caitimiinuid^
558 AETERIES.
first interosseous space, wliere it divides into two branches, tlie dorsalis halincis
and communicating.
Relations. This vessel, in its course forwards, rests upon the astragalus,
scaphoid, and internal cuneiform bones and the ligaments connecting them,
being covered by the integument and fascia, and crossed near its termination by
the innermost tendon of the Extensor brevis digitorum. On its tilial side is
the tendon of the Extensor proprius poUicis; on its fibular side, the innermost
tendon of the Extensor longus digitorum, and the termination of the anterior
tibial nerve. It is accompanied by two veins.
Plax of the Eelations of the Doksalis Pedis Artery.
In front.
Integument and fascia.
Innermost tendon of Extensor brevis diiritorum.
Tibial side.
Fibular side.
Extensor proprius pollicis. I ^^^''- j Extensor longus digitorum.
^ ^ ^ V y Anterior tibial nerve.
Behind.
Astragalus.
Scaphoid.
Internal cuneiform,
and their ligaments.
Peculiarities in Size. The dorsal artery of the foot may be larger than usual, to compensate
for a deficient plantar artery; or it may be deficient in its terminal branches to the toes, which
are then derived from the internal plantar ; or its place may be supplied altogether by a large
anterior peroneal artery.
Pofiitio7i. This artery frequently curves outwards, lying external to the line between the
middle of the ankle and the back part of the first interosseous space.
Surgical Anaiomy. This artery may be tied, by making an incision through the integument,
between two and three inches in length, on the fibular side of the tendon of the Extensor proprius
pollicis, in the interval between it and the inner border of the short Extensor muscle. The in-
cision should not extend further forwards than the back part of the first interosseous space, as the
artery divides in that situation. The deep fascia being divided to the same extent, the artery
will be exposed, the nerve lying upon its outer side.
Branches. The branches of the dorsalis pedis are the
Tarsal. Dorsalis pollicis, or hallucis.
Ltarsal.
Interosseous.
Metatarsal. Communicating
The tarsal artery arises from the dorsalis pedis, as that vessel crosses the
scaphoid bone ; it passes in an arched direction outwards, lying upon the tarsal
bones, and covered by the Extensor brevis digitorum ; it supplies that muscle
and the articulations of the tarsus, and anastomoses with branches from the
metatarsal, external malleolar, peroneal, and external plantar arteries.
The metatarsal arises a little anterior to the preceding ; it passes outwards to
the outer part of the foot, over the bases of the metatarsal bones, beneath the
tendons of the short Extensor, its direction being influenced by its point of
origin ; and it anastomoses with the tarsal and external plantar arteries. This
vessel gives off three branches, the interosseous, which pass forwards upon the
three outer Dorsal interossei muscles, and, in the clefts between the toes, divide
into two dorsal collateral branches for the adjoining toes. At the back part of
each interosseous space these vessels receive the posterior perforating branches
from the plantar arch ; and at the fore part of each interosseous space, they are
joined by the anterior perforating branches, from the digital arteries. The outer-
most interosseous artery gives oft' a branch which supplies the outer side of the
little toe.
POSTERIOR TIBIAL. 559
The dorsalis hallucis runs forwards along the outer border of the first meta-
tarsal bone, and, at the cleft between the first and second toes, divides into two
branches, one of which 23asses inwards, beneath the tendon of the Extensor
proprius pollicis, and is distributed to the inner border of the great toe ; the
other branch bifurcating to supply the adjoining sides of the great and second
toes.
The communicating artery dips down into the sole of the foot, between the two
heads of the first Dorsal interosseous muscle, and inosculates with the termina-
tion of the external plantar artery, to complete the plantar arch. It here gives
off two digital branches ; one runs along the inner side of the great toe, on its
plantar surface ; the other passes forwards along the first metatarsal space, and
bifurcates for the supply of the adjacent sides of the great and second toes.
PosTERioE Tibial Artery. (Fig. 329.)
The Posterior Tibial is an artery of large size, which extends obliquely down-
wards from the lower border of the Popliteus muscle, along the tibial side of the
leg, to the fossa between the inner ankle and the heel, where it divides beneath
the origin of the Abductor pollicis, into the internal and external plantar arteries.
At its origin it lies opposite the interval between the tibia and fibula ; as it
descends, it approaches the inner side of the leg, lying behind the tibia, and, in
the lower part of its course, is situated midway between the inner malleolus
and the tuberosity of the os calcis.
Relations. It lies successively upon the Tibialis posticus, the Flexor longus
digitorum, the tibia and the back part of the ankle-joint. It is covered by the
intermuscular fascia, which separates it above from the Gastrocnemius and Soleus
muscles. In the lower third, where it is more superficial, it is covered only by
the integument and fascia, and runs parallel with the inner border of the tendo
Achillis. It is accompanied by two veins, and by the posterior tibial nerve,
which lies at first to the inner side of the artery, but soon crosses it, and is, in
the greater part of its course, on its outer side.
Plan of the Eelations of the Posterior Tibial Artery.
In front.
Tibialis posticus.
Flexor longus digitorum.
Tibia.
Ankle-joi'nt. ,
Inner side. I posterior \ Outer side.
Posterior tibial nerve, ( Tibial. J Posterior tibial nerve,
upper third. V y lower two-thirds.
Behind.
Gastrocnemius.
Soleus.
Deep fascia and integument.
Behind the Inner Ankle, the tendons and bloodvessels are arranged in the
following order, from within outwards : First, the tendons of the Tibialis posticus
and Flexor longus digitorum, lying in the same groove, behind the inner mal-
leolus, the former being the most internal. External to these is the posterior
tibial artery, having a vein on either side ; and, still more externally, the poste-
rior tibial nerve. About half an inch nearer the heel is the tendon of the Flexor
longus pollicis.
Peculiarities in Size. The posterior tibial is not unfrequently smaller than usual, or absent,
its place being supplied by a large peroneal artery, which passes inwards at the lower end of the
tibia, and either joins the small tibial artery, or continues alone to the sole of the foot.
560 ARTERIES.
Surgical Anatomy. The application of a ligature to the posterior tibial may be required in
cases of wound of the sole of the foot, attended with great hemorrhage, when the vessel should
be tied at the inner ankle. In cases of wound of the posterior tibial, it will be necessary to
enlarge the wound so as to expose the vessel at the wounded point, excepting where the vessel is
injured by a punctured wound from the front of the leg. In cases of aneurism from wound of the
artery low down, the vessel should be tied in the middle of the leg. But in aneurism of the
posterior tibial high up, it would be better to tie the femoral artery.
To tie the posterior tibial artery at the ankle, a semilunar incision should be made through the
integument, about two inches and a half in length, midway between the heel and inner ankle, or
a little nearer the latter. The subcutaneous cellular membrane having been divided, a strone-
and dense fascia, the internal annular ligament, is exposed. This ligament is continuous above
with the deep fascia of the leg. covers the vessels and nerves, and isintimately adherent to the
sheaths of the tendons. This having been cautiously divided upon a director, the sheath of the
vessels is exposed, and being opened, the ai-tery is seen with one of the vense comites on each side.
The aneurism needle should be passed round the vessel from the heel towards the ankle, in order
to avoid the posterior tibial nerve, care being at the same time taken not to include the venae
comites.
The vessel may also be tied in the lower third of the leg by making an incision about three
inches in length, parallel with the inner margin of the tendo Achillis. The internal saphenous
vein being carefully avoided, the two layers of fascia must be divided upon a director, when the
artery is exposed along the outer margin of the Flexor longus digitorum, with one of its venae
comites on either side, and the nerve lying external to it.
To tie the posterior tibial in the middle of the leg is a very difficult operation, on account of
the great depth of the vessel from the surface, and its being covered by the Gastrocnemius and
Soleus muscles. The patient being placed in the recumbent position, the injured limb should
rest on its outer side, the knee being partially bent, and the foot extended, so as to relax the
muscles of the calf. An incision about four inches in length should then be made through the
integument, a finger's breadth behind the inner margin of the tibia, taking care to avoid the in-
ternal saphenous vein. The deep fascia having been divided, the margin of the Gastrocnemius
is exposed, and must be drawn aside, and the tibial attachment of the Soleus divided, a director
being previously passed beneath it. The artery may now be felt pulsating beneath the deep
fascia, about an inch from the margin of the tibia. The fascia having been divided, and the
limb placed in such a position as to relax the muscles of the calf as much as possible, the veins
should be separated from the artery, and the aneurism needle passed round the vessel from without
inwards, so as to avoid wounding the posterior tibial nerve.
The branclies of tlie posterior tibial artery are, tlie
Peroneal. JSTutrient.
Anterior peroneal. Communicating.
Muscular. Internal calcanean.
Tlie Peroneal Artery lies, deeply seated, along the back part of the fibular
side of the leg. It arises from the posterior tibial, about an inch below the
lower border of the Popliteus muscle, passes obliquely outwards to the fibula,
and then descends along the inner border of that bone to the lower third of the
leg, where it gives off the anterior peroneal. It then passes across the articu-
lation between the tibia and fibula, to the outer side of the os calcis, supplying
the neighboring muscles and back of the ankle, and anastomosing with the ex-
ternal madeolar, tarsal, and external plantar arteries.
Relations. This vessel rests at first upon the Tibialis posticus, and, in the
greater part of its course, in the fibres of the Flexor longus pollicis, in a groove
between the interosseous membrane and the bone. It is covered in the upper
part of its course by the Soleus and deep fascia; l)eloiL\ by the Flexor longus
jjollicis.
PERONEAL. ' 5G1
Plan of the Eelations of the Peroneal Artery.
In front.
Tibialis posticus.
Flexor lougus pollicis.
Outer side.
Fibula.
Bthind.
Soleus.
Deep fascia.
Flexor longus pollicis.
Peculiarities in Origin. The peroneal artery may arise three inches below the Popliteus, or
from the posterier tibial high up, or even from the popliteal.
Its Size is more frequently increased than diminished ; and then it either reinforces the posterior
tibial by its junction with it, or altogether takes the pUice of the posterior tibial in the lower part
of the leg and foot, the latter vessel only existing as a short muscular branch. In those rare
cases where the peroneal artery is smaller than usual, a branch from the posterior tibial supplies
its place; and a branch from the anterior tibial cnmpensates for the diminished anterior peroneal
artery. In one case, the peroneal artery has been found entirely wanting.
The anterior peroneal is sometimes enlarged, and takes the place of the dorsal artery of the
foot.
The peroneal arterj, in its course, gives off brandies to the Soleus, Tibialis
posticus. Flexor longus pollicis, and Peronei muscles, and a nutrient branch to
the fibula.
The Anterior Peroneal.^ the only named branch of the peroneal arterj, pierces
the interosseous membrane, about two inches above the outer malleolus, to reach
the fore part of the leg, and passing down beneath the Peroneus tertius, to the
outer ankle, ramifies on the front and outer side of the tarsus, anastomosing
with the external malleolar and tarsal arteries.
The nutrient artery of the tibia arises from the posterior tibial near its origin,
and, after supplying a few muscular branches, enters the nutrient canal of that
bone, which it traverses obliquely from above downwards. This is the largest
nutrient artery of bone in the body.
The muscular hranches of the posterior tibial are distributed to the Soleus and
deep muscles along the back of the leg.
The communicating branch to the peroneal runs transversely across the back
of the tibia, about two inches above its lower end, passing beneath the Flexor
longus pollicis.
The internal cahanean are several large arteries, which arise from the poste-
rior tibial just before its division ; they are distributed to the fat and integu-
ment behind the tendo Achillis and about the heel, and to the muscles on the
inner side of the sole, anastomosing with the peroneal and internal malleolar
arteries.
The Internal Plantar Artery (Figs. 331, 332), much smaller than the external,
passes forwards along the inner side of the foot. It is at first situated above^
the Abductor pollicis, and then between it and the Flexor brevis digitorum,
both of which it supplies. At the base of the first metatarsal bone, where it
has become much diminished in size, it passes along the inner border of the
great toe, inosculating with its digital branches.
The External Plantar Artery, much larger than the internal, passes obliquely
outwards and forwards to the base of the "fifth metatarsal bone. It then turns
' This refers to the erect position of the body. In the ordinary dissection, the artery is deeper
than the muscle.
36
562
AETERIES.
obliquely inwards to tlie interval between tlie bases of the first and second meta-
tarsal bones, wliere it anastomoses with the commnnicating branch from the
dorsalis pedis artery, thns completing the plantar arch. As this artery passes
outwards, it is at first placed between the os calcis and Abductor poUicis, and
then between the Flexor brevis digitorum and Flexor accessorius ; and as it
passes forwards to the base of the little toe, it lies more superficially between
the Flexor brevis digitorum, and Abductor minimi digiti, covered by the deep
fascia and integument. The remaining portion of the vessel is deeply situated ;
it extends from the base of the metatarsal bone of the little toe to the back part
of the first interosseous space, and forms the plantar arch ; it is convex forwards,
lies upon the Interossei muscles, opposite the tarsal ends of the metatarsal bones,
and is covered by the Adductor pollicis, the flexor tendons of the toes, and the
Lumbricales.
Branches. The plantar arch, besides distributing numerous branches to the
muscles, integument, and fasciee in the sole, gives of!' the following branches : —
Posterior perforating. Digital — Anterior perforating.
The Posterior Perforating are three small branches, which ascend through the
back part of the three outer interosseous spaces, between the heads of the Dorsal
interossei muscles, and anastomose with the interosseous branches from the
metatarsal artery.
Fig. 331. — The Plantar Arteries.
Superficial View.
Fig-. 332.- The Plantar Arteries.
Deep View.
The Difjital Branches are four in number, and supply the three outer toes and
half the second toe. ^\\q, first passes outwards from the outer side of the plantar
arch, and is distributed to the outer side of the little toe, passing in its course
beneath the Abductor and short Flexor muscles. The second^ thirds nud fourth
run forwards along the metatarsal s])accs, and on arriving at the clefts b&twccn
the toes divide into collateral branches, which sni)|)ly flu; subjacent sides of the
three outer toes and the outer side of the seccjud. At the bifurcation of the
PULMONARY. 563
toes, eacli digital artery sends upwards, through the forepart of the corre-
sponding metatarsal space, a small branch, which inosculates with the inter-
osseous branches of the metatarsal artery. These are the anterior perforating
branches.
From the arrangement already described of the distribution of the vessels to
the toes, it will be seeii that both sides of the three outer toes, and the outer
side of the second toe, are supplied by branches from the plantar arch ; both
sides of the great toe, and the inner side of the second, being supplied by the
dorsalis hallucis.
Pulmonary Artery.
The Pulmonary Artery conveys the venous blood from the right side of the
heart to the lungs. It is a short wide vessel, about two inches in length, arising
from the left side of the base of the right ventricle, in front of the aorta. It
ascends obliquely upwards, backwards, and to the left side, as far as the under
surface of the arch of the aorta, where it divides into two branches of nearly
equal size, the right and left pulmonary arteries.
Relations. The greater part of this vessel is contained, together with the
ascending part of the arch of the aorta, in the pericardium, being inclosed with
it in a tube of serous membrane, continued upwards from the base of the heart,
and has attached to it, above, the fibrous layer of the membrane. Behind, it
rests at first upon the ascending aorta, and higher up lies in front of the left
auricle. On either side of its origin is the appendix of the corresponding
auricle, and a coronary artery ; and higher up it passes to the left side of the
ascending aorta.
A little to the left of its point of bifurcation, it is connected to the under
surface of the arch of the aorta by a short fibrous cord, the remains of a vessel
peculiar to foetal life, the ductus arteriosus.
The right pulmonary artery^ longer and larger than the left, runs horizontally
outwards, behind the ascending aorta and superior vena cava, to the root of the
right lung, where it divides into two branches, of which the lower, which is the
larger, supplies the lower lobe ; the upper giving a branch to the middle lobe.
The left pulmonary artery, shorter but somewhat smaller than the right, passes
horizontally in front of the descending aorta and left bronchus to the root of the
left lung, where it divides into two branches for the two lobes.
The terminal branches of the pulmonary artery will be described with the
anatomy of the lung.
The author has to acknowledge valuable aid derived from the followiu": works : Harrison's
" Surgical Anatomy of the Arteries of the Human Body." Dublin, 1824. — Richard Quain's
"Anatomy of the Arteries of the Human Body." London, 1844. — Sibson's " Medical Anatomy ;"
and the other works ou General and Microscopic Anatomy before referred to.
Of the Veins.
The Veins are the vessels wliich serve to return the blood from the capilla-
ries of the different parts of the body to the heart. They consist of two distinct
sets of vessels, the pulmonary and systemic.
The Pulmonary Veins, unlike other vessels of this kind, contain arterial blood,
which they return from the lungs to the left auricle of the heart.
The /Systemic Veins return the venous blood from the body generally to the
right auricle of the heart.
The Portal Vein, an appendage to the systemic venous system, is confined
to the abdominal cavity, returning the venous blood from the viscera of diges-
tion, and carrying it to the liver by a single trunk of large size, the vena portee.
From this organ, the same blood is conveyed to the inferior vena cava by means
of the hepatic veins.
The veins, like the arteries, are found in nearly every tissue of the body.
They commence by minute plexuses which communicate with the capillaries.
The branches which have their commencement in these plexuses unite together
into trunks, and these, in their passage towards the heart, constantly increase
in size as they receive branches, and join other veins similar in size to them-
selves. The veins are larger and altogether more numerous than the arteries;
hence, the entire capacity of the venous system is much greater than that of the
arterial ; the pulmonary veins excepted, which do no exceed in capacity the pul-
monary arteries. From the combined area of the smaller venous branches
being greater than the main trunks, it results, that the venous system represents
a cone, the summit of which corresponds to the heart : its base to the circum-
ference of the body. In form, the veins are not perfectly cylindrical like the
arteries, their walls being collapsed when empty, and the uniformity of their
surface being interrupted at intervals by slight contractions, which indicate the
existence of valves in their interior. They usually retain, however, the same
calibre as long as they receive no branches.
The veins communicate very freely with one another, especially in certain
regions of the body ; and this communication exists between the larger trunks
as well as between the smaller branches. Thus, in the cavity of the cranium,
and between the veins of the neck, where obstruction would be attended with
imminent danger to the cerebral venous system, we find that the sinuses and
larger veins have large and very frequent anastomoses. The sanie free com-
munication exists between the veins throughout the whole extent of the spinal
canal, and between the veins composing the various venous plexuses in the
abdomen and pelvis, as the spermatic, uterine, vesical, prostatic, etc.
The veins are subdivided into three sets: superficial, deep, and sinuses.
The /Superficial or Cutaneous Veins are found between the layers of superficial
fascia, immediately beneath the integument ; they return the blood from these
structures, and communicate with the deep veins by perforating the deep fascia.
The Deep Veins accompany the arteries, and arc usually inclosed in the same
slieath with tliosc vessels. In the smaller arteries, as the radial, ulnar, bracliial,
tibial, peroneal, they exist generally in pairs, one lying on each side of the
vessel, and arc called venoe comites. The larger arteries, as the axillary, sub-
clavian, popliteal, and femoral, have usually only one accompanying vein. In
certain organs of the body, however, the dccjo veins do not accompany the
arteries; for instance, tlic veins in the skull and sjiinal canal, the hepatic veins
in tlic liver, and llic larger veins returning blotjd (Voiu the osseous tissue.
(o04) .
OF THE HEAD AND NECK. 565
Sinuses are venous cliannels, which, in their structure and mode of distribu-
tion, differ altogether from the veins. They are found only in the interior of
the skull, and are formed by a separation of the layers of the dura mater ; their
outer coat consisting of fibrous tissue, their inner of a serous membrane con-
tinuous with the serous membrane of the veins.
Yeins have thinner walls than arteries, the difference in thickness being due
to the small amount of elastic and muscular tissues which the veins contain.
The superficial veins usually have thicker coats than the deep veins, and the veins
of the lower limb are thicker than those of the upper.
The minute structure of these vessels is described in the Introduction,
The veins may be arranged into three groups: 1, Those of the head and
neck, upper extremity, and thorax, which terminate in the superior vena cava.
2. Those of the lower limb, pelvis, arid abdomen, which terminate in the inferior
vena cava. 3. The cardiac veins, which open directly into the right auricle of
the heart.
Yeins of the Head and Neck,
The "Veins of the Head and ISTeck may be subdivided into three groups: 1.
The veins of the exterior of the head. 2. The veins of the neck, 3, The veins
of the diploe and interior of the cranium.
The veins of the exterior of the head are, the
Facial. Temporo-maxillary.
Temporal. Posterior auricular.
Internal maxillary. Occipital.
The Facial Vein passes obliquely across the side of the face, extending from
the inner angle of the orbit, downwards and outwards, to the anterior margin
of the Masseter muscle. It lies to the outer side of the facial artery, and is not
so tortuous as that vessel. It commences in the frontal region, where it is called
\h.e frontal vein; at the inner angle of the eye it has received the name of the
angular vein; and from this point to its termination is called \X\q facial vein.
The frontal vein commences on the anterior part of the skull, by a venous
plexus, which communicates with the anterior branches of the temporal vein ;
the veins converge to form a single trunk, which runs downwards near the
middle line of the forehead parallel with the vein of the opposite side, and unites
with it at the root of the nose, by a transverse trunk, called the nasal arch.
Occasionally, the frontal veins join to form a single trunk, which bifurcates at
the root of the nose into the two angular veins. At the nasal arch the branches
diverge, and run along the side of the root of the nose. The frontal vein as it
descends upon the forehead receives the supraorbital vein ; the dorsal veins of
the nose terminate in the nasal arch ; and the angular vein receives the veins of
the ala nasi on its inner side, and the superior palpebral veins on its outer side ;
it moreover communicates with the ophthalmic vein, which establishes an
important anastomosis between this vessel and the cavernous sinus.
The /aci a? vein commences at the inner angle of the orbit, being a continua-
tion of the angular vein. It passes obliquely downwards and outwards, beneath
the Zygomaticus major muscle, descends along the anterior border of the Masse-
ter, crosses over the body of the lower jaw, with the facial artery, and, passing
obliquely outwards and backwards, beneath the Platysma and cervical fascia,
unites with a branch of commimication from the temporo-maxillary vein, to
form a trunk of large size which enters the internal jugular.
Branches. The facial vein receives, near the angle of the mouth, communi-
cating branches from the pterygoid plexus. It is also joined by the inferior
palpebral, the superior and inferior labial veins, the buccal veins from the cheek,
and the masseteric veins. Below the jaw it receives the submental, the infe-
rior palatine, which returns the blood from the plexus around the tonsil and
566
VEINS.
soft palate ; tlie sabmaxillary vein, wliicli commences in tlie submaxillary
gland; and lastly, tlie ranine vein.
Fig. 333.- Veins of the Head and Neck.
The Temporal Vein commences by a minute plexus on the side and vertex of
the skull, which communicates with the frontal vein in front, the corresponding
vein of the opposite side, and tlie posterior auricular and occipital veins behind.
From this network, anterior and posterior branches are formed which unite above
the zygoma, forming the trunk of the vein. This trunk is joined in this situation
by a large vein, tlic middle temporal, which receives the blood from the substance
of the Temporal.muscle and pierces the fascia at the upper border of the zygoma.
The temporal vein then descends between the external auditory meatus and the
condyle of the jaw, enters the substance of the parotid gland, and unites with
the internal maxillary vein, to form the temporo-maxillary.
Jiranches. The temporal vein receives in its course some ]')arotid veins, an
{irticular branch from the articulation of the jaw, anterior auricular veins from
the external car, and a vein of large size, the transverse facial, from the side of
the face.
OF THE NECK. 567
The Internal Maxillary Vein is a vessel of considerable size, receiving brandies
wliicli correspond with those of the internal maxillary artery. Thus it receives
the middle meningeal veins, the deep temporal, the pterygoid, masseteric, and
buccal, som6 palatine veins, and the inferior dental. These branches form a
large plexus, the pterygoid, which is placed between the Temporal and External
pterygoid, and partly between the Pterygoid muscles. This plexus communi-
cates very freely with the facial vein, and with the cavernous sinus, by branches
through the base of the skull. The trunk of the vein then passes backwards,
behind the neck of the lower jaw, and unites with the temporal vein, forming
the temporo-maxillary.
The Temporo-maxillary Vein^ formed by the union of the temporal and internal
maxillary vein, descends in the substance of the parotid gland, between the
ramus of the jaw and the Sterno-mastoid muscle, and divides into two branches,
one of which passes inwards to join the facial vein, the other is continuous with
the external jugular. It receives near its termination the posterior auricular vein.
The Posterior Auricular Vein commences upon the side of the head, by a
plexus which communicates with the branches of the temporal and occipital
veins. The vein descends behind the external ear and joins the temporo-max-
illary, just before that vessel terminates in the external jugular. This vessel
receives the stylo- mastoid vein, and some branches from the back part of the
external ear.
The Occipital Vein commences at the back part of the vertex of the skull,
by a plexus in a similar manner with the other veins. It follows the course of
the occipital artery, passing deeply beneath the muscles of the back part of the
neck, and terminates in the internal jugular, occasionally in the external jugular.
As this vein passes opposite the mastoid process, it receives the mastoid vein,
which establishes a communication with the lateral sinus.
Yeins of the Neck.
The Veins of the Neck, which return the blood from the head and face, are
the
External jugular. Anterior jugular.
Posterior external jugular. Internal jugular.
Vertebral,
The External Jugular Vein receives the greater part of the blood from the
exterior of the cranium and deep parts of the face, being a continuation of the
temporo-maxillary and posterior auricular veins. It commences in the sub-
stance of the parotid gland, on a level with the angle of the lower jaw, and runs
perpendicularly down the neck, in the direction of a line drawn from the angle
of the jaw to the middle of the clavicle. In its course it crosses the Sterno-
mastoid muscle, and runs parallel with its posterior border as far as its attach-
ment to the clavicle, where it perforates the deep fascia, and terminates in the
subclavian vein, on the outer side of the internal jugular. In the neck it is
separated from the Sterno-mastoid by the anterior layer of the deep cervical
fascia, and is covered by the Platysma, the superficial fascia, and the integu-
ment. This vein is crossed about its middle by the superficial cervical nerve,
and its upper half is accompanied by the auricularis magnus nerve. The ex-
ternal jugular vein varies in size, bearing an inverse proportion to that of the
other veins of the neck ; it is occasionally double. It is provided with two pairs
of valves, the lower pair being placed at its entrance into the subclavian vein,
the upper pair in most cases about an inch and a half above the clavicle. These
valves do not prevent the regurgitation of the blood, or the passage of injection
from below upwards.^
' The student may refer to an interesting paper by Dr. Strnthers. " On Jugular Venesection
in Asphyxia, Anatomically and Experimentally Considered, including the Demonstration of
Valves in the Veins of the Neck," in the Edinburgh Medical Journal, for November, 1856.
568 VEINS.
Branches. This vein receives tlie occipital occasionally, the posterior external
jugular, and, near its termination, the suprascapular and transverse cervical
veins. It communicates with the anterior jugular, and, in the substance of the
parotid, receives a large branch of communication from the internal jugular.
The Posterior External Jugular Vein returns the blood from the integument
and superficial muscles in the upper and back part of the neck, lying between
the Splenius and Trapezius muscles. It runs down the back part of the neck,
and opens into the external jugular just below the middle of its course.
The Anterior Jugular Vein collects the blood from the integument and muscles
in the middle of the anterior region of the neck. It passes down between the
median line and the anterior border of the sterno- mastoid, and, at the lower part
of the neck, passes beneath that muscle to open into the termination of the
external jugular, or into the subclavian vein (Fig. 338). This vein varies con-
siderably in size, bearing almost always an inverse proportion to the external
jugular. Most frequently there are two anterior jugulars, a right and left ; but
occasionally only one. This vein receives some laryngeal branches, and occa-
sionally an inferior thyroid vein. Just above the sternum, the two anterior
jugular veins communicate by a transverse trunk, which receives branches from
the inferior thyroid veins. It also communicates with the external and with
the internal jugular. There are no valves in this vein.
The Internal Jugular Vein collects the blood from the interior of the cranium,
from the superficial parts of the face, and from the neck. It commences at the
jugular foramen, in the base of the skull, being formed by the coalescence of the
lateral and inferior petrosal sinuses. At its origin it is somewhat dilated, and
this dilatation is called the sinus, or gulf, of the internal jugular vein. It runs
down the side of the neck in a vertical direction, lying at first on the outer side
of the internal carotid, and then on the outer side of the common carotid, and
at the root of the neck unites with the subclavian vein, to form the vena innomi-
nata. The internal jugular vein, at its commencement, lies upon the Rectus
lateralis, behind, and at the outer side of the internal carotid, and the eighth and
ninth pairs of nerves ; lower down, the vein and artery lie upon the same plane,
the glosso-pharyngeal and hypoglossal nerves passing forwards between them ;
the pneumogastric descends between and behind them, in the same sheath ; and
the spinal accessory passes obliquely outwards, behind the vein. At the root
of the neck the vein of the right side is placed at a little distance from the
artery ■; on the left side, it usually crosses it at its lower part. The right internal
jugular vein crosses the first part of the subclavian artery. This vein is of
considerable size, but varies in different individuals, the left one being usualh''
the smaller. It is provided with a pair of valves, which are placed at its point
of termination, or from half to three-quarters of an inch above it.
Branches. This vein receives in its course the facial, lingual, pharjmgeal,
superior and middle thyroid veins, and sometimes the occipital. At its point of
junction with the branch common to the temporal and facial veins, it becomes
greatly increased in size.
The lingual veins commence on the dorsum, sides, and under surface of the
tongue, and passing backwards, following the course of the lingual artery and
its branches, terminate in the internal jugular.
T\iG pharyngeal vein commences in a minute plexus, the pharyngeal, at the
back part and sides of the pharynx, and after receiving meningeal branches, and
the Vidian and spheno-palatine veins, terminates in the internal jugular. It
occasionally opens into the facial, lingual, or superior thyroid vein.
The superior thyroid vein commences in the substance and on the surface of
the thyroid gland, by branches corresponding with those of the superior th3'roid
artery, and terminates in the upper part of the internal jugular vein.
The middle thyroid vein collects the blood from the lower part of the lateral
lobe of the thyroid gland, and being joined by some branches from the larynx
and trachea, terminates in the lower part of the internal jugular vein.
OF THE DIPLOE.
569
The occipital vein lias been described above.
The Vertebral Vein commences in the occipital region, by numerous small
branches, from the deep muscles at the upper and back part of the neck, passes
outwards, and enters the foramen in the transverse process of the atlas, and
descends by the side of the vertebral artery, in the canal formed by the trans-
verse processes of the cervical vertebras. Emerging from the foramen in the
transverse process of the sixth cervical, it terminates at the root of the neck in
the back part of the innominate vein near its origin, its mouth being guarded
by a pair of valves. On the right side, it crosses the first part of the subclavian
artery. This vein, in the lower part of its course, occasionally divides into two
branches, one of which emerges with the artery at the sixth cervical vertebra :
tiie other escapes through the foramen in the seventh cervical.
Branches. The vertebral vein receives in its course the posterior condyloid
vein, muscular branches from the muscles in the prevertebral region ; dorsi-spinal
veins, from the back part of the cervical portion of the spine ; meningo-rachidian
veins, from the interior of the spinal canal ; and lastly, the ascending and deep
cervical veins.
VeijSts of the Diploe.
The diploe of the cranial bones is channelled in the adult by a number of
tortuous canals, which are lined by a more or less complete layer of compact
Fig. 334. — Veins of the Diploe, as displayed by the Removal of the Outer Table of the Skull.
tissue. The veins they contain are large and capacious, their walls being thin,
and formed only of epithelium, resting upon a layer of elastic tissue, and they
present, at irregular intervals, punch-like dilatations, or culs-de-sac^ which serve
as reservoirs for the blood. These are the veins of the diploe : they can only
be displayed by removing the outer table of the skull.
In adult life, as long as the cranial bones are distinct and separable, these
veins are confined to the particular bones ; but in old age, when the sutures are
united, they communicate with each other, and increase in size. These vessels
communicate, in the interior of the cranium, with the meningeal veins, and with
the sinuses of the dura mater ; and on the exterior of the slcull, with the veins
of the pericranium. They are divided into the frontal^ which opens into the
supraorbital vein, by an aperture at the supraorbital notch ; the anterior tempo-
570 VEINS.
ra?, wTiich is confined chiefly to the frontal bone, and opens into one of the deep
temporal veins, after escaping by an aperture in the great wing of the sphenoid ;
the posterior temporal^ which is confined to the parietal bone, and terminates in
the lateral sinus bj an aperture at the posterior inferior aiigle of the parietal
bone ; and the occipital^ which is confined to the occipital bone and opens either
into the occipital vein, or the occipital sinus.
Cerebeal Veins.
The Cerebral Veins are remarkable for the extreme thinness of their coats, in
consequence of the muscular tissue in them being wanting, and for the absence
of valves. They may be divided into two sets, the superficial, which are placed
on the surface, and the deep veins, which occupy the interior of the organ.
The Superficial Cerebral Veins ramify upon the surface of the brain, being
lodged in the sulci, between the convolutions, a few running across the convolu-
tions. They receive branches from the substance of the brain, and terminate in
the sinuses. They are named, from the position they occupy, superior, inferior,
internal, and external.
The Superior Cerebral Veins ^ seven or eight in number on each side, pass
forwards and inwards towards the great longitudinal fissure, where they receive
the internal cerebral veins, which return the blood from the convolutions of the
flat surface of the corresponding hemisphere; near their termination, they
become invested with a tubular sheath of the arachnoid membrane, and open
into the superior longitudinal sinus, in the opposite direction to the course of
the blood. The external cerebral veins also open chiefly into these veins.
The Inferior Anterior Cerebral Veins commence on the under surface of the
anterior lobes of the brain, and terminate in the cavernous sinuses.
The Inferior Lateral Cerebral Veins commence on the lateral parts of the
hemispheres, and at the base of the brain: they unite to form from three to five
veins, which open into the lateral sinus from before backwards. One of these
sometimes opens into the superior petrosal sinus.
The Inferior Median Cerebral Veins ^ which are very large, commence at the
fore part of the under surface of the cerebrum, and from the convolutions of the
posterior lobe, and terminate in the straight sinus behind the vense Galeni.
The Deep Cerebral^ or Ventricular Veins (vense Galeni), are two in number,
one from the right, the other from the left, ventricle. They are each formed
by two veins, the vena corporis striati, and the choroid vein. They run back-
wards, parallel with one another, inclosed within the velum interpositum, and
pass out of the brain at the great transverse fissure, between the under surface
of the corpus callosum and the tubercula quadrigemina, to enter the straight
sinus.
The vena corporis striati commences in the groove between the corpus striatum
and thalamus opticus, receives numerous veins from both of these parts, and
unites behind the anterior pillar of the fornix with the choroid vein, to form one
of the ven« Galeni.
The choroid vein runs alonaf the whole leng-th of the outer border of the cho-
roid plexus, receiving veins from the hippocampus major, the fornix and corpus
callosum, and unites, at the anterior extremity of the choroid plexus, with the
vein of the corpus striatum.
Tlie Cerebellar Veins occupy the surface of the cerebellum, and are disposed
in three sets, superior, inferior, and lateral. The superior pass forwards and
inwards, across the superior vermiform process, and terminate in the straight
pinus : some open into the vena; Galeni. Tlie inferior cerebellar veins, of large
size, run transvers(;ly outwards, and terminate l)y two or three trunks in the
lateral sinuses. The lateral anterior cerebellar veins terminate in the superior
petrosal sinuses.
OF THE DURA MATER.
571
Sinuses of the Duea Mater.
The Sinuses of tlie Dura Mater are venous cliannels, analogous to the veins,
their outer coat being formed bj the dura mater ; their inner, bj a continuation
of the serous membrane of the veins. They are fifteen in number, and are
divided into two sets : 1. Those situated at the upper and back part of the
skull; 2. Those at the base of the skull. The former are the
Straisfht sinus.
Superior longitudinal.
Inferior lonoitudinal.
Occipital sinuses.
Lateral sinuses.
The Sujoerior Longitudinal Shius occupies the attached margin of the falx
cerebri. Commencing at the crista galli, it runs from before backwards, groov-
Fig. 335. — Yertical Section of the Skull, showing the Sinuses of the Dura Mater.
/■ara.-nc" CccatT
ing the inner surface of the frontal, the adjacent margins of the two parietal,
and the superior division of the crucial ridge of the occipital bone, and termi-
nates bv dividing into the two lateral sinuses. This sinus is triangular in form,
narrow in front, and gradually increasing in size as it passes backwards. On
examining its inner surface, it presents the internal openings of the cerebral
veins, which run, for the most part, from behind forwards, and open chiefly at
the back part of the sinus, their orifices being concealed by fibrous areolae ;
numerous fibrous bands [chordse WilUsii) are also seen, which extend trans-
versely across the inferior angle of the sinus ; £fnd lastly, some small, white,
projecting bodies, the glandul^e Pacchioni. This sinus receives the superior
cerebral veins, numerous veins from the diploe and dura mater, and, at the
posterior extremity of the sagittal and parietal suture, veins from the pericra-
nium.
The point where the superior longitudinal and lateral sinuses are continuous is
called the confluence of the sinuses, or the torcular Herophili. It presents a
considerable dilatation, of very irregular form, and is the point of meeting of
six sinuses, the superior longitudinal, the two lateral, the two occipital, and the
straight.
The Inferior Longitudinal Sinus, more correctly described as the inferior
longitudinal vein, is contained in the posterior part of the free margin of the
falx cerebri. It is of a circular form, increases in size as it passes backwards,
and terminates in the straight sinus. It receives several veins from the falx
cerebri, and occasionally a few from the flat surface of the hemispheres.
572 VEINS.
Tlie Straight Sinus is situated at the line of junctian of tlie falx cerebri with
the tentorium. It is triangular in form, increases in size as it proceeds back-
wards, and runs obliquely downwards and backwards from the termination of
the inferior longitudinal sinus to the torcular Herophili, Besides the inferior
longitudinal sinus, it receives the vense Galeni, the inferior median cerebral
veins, and the superior cerebellar. A few transverse bands cross its interior.
The Lateral Sinuses are of large size, and are situated in the attached margin
of the tentorium cerebelli. They commence at the torcular Herophili, and
' passing horizontally outwards to the base of the petrous portion of the temporal
bone, curve downwards and inwards on each side to reach the jugular foramen,
where they terminate in the internal jugular vein. Each sinus rests in its
course, upon the inner surface of the occipital, the posterior inferior angle of
the parietal, the mastoid portion of the temporal, and on the occipital again just
before its termination. These sinuses are frequently of unequal size, and they
increase in size as they proceed from behind forwards. The horizontal portion
is of a triangular form, the curved portion semi- cylindrical; their inner surface
is smooth, and not crossed by the tibrous bands found in the other sinuses.
These sinuses receive blood from the superior longitudinal, the straight, and
the occipital sinuses ; and in front they communicate with the superior and infe-
rior petrosal. They communicate with the veins of the pericranium by means
of the mastoid and posterior condyloid veins, and they receive the inferior cere-
bral and inferior cerebellar veins, and some veins from the diploe.
The Occipital are the smallest of the cranial sinuses. They are usually two
in number, and situated in the attached margin of the falx cerebelli. They
commence by several small veins around the posterior margin of the foramen
magnum, which communicate with the posterior spinal veins, and terminate by
saparate openings (sometimes by a single aperture) in the torcular Herophili.
The sinuses at the base of the skull are the
Cavernous. Inferior petrosal.
Circular. Superior petrosal.
Transverse.
The Cavernous Sinuses are named from their presenting a reticulated structure.
They are two in number, of large size, and placed one on each side of the sella
Turcica, extending from the sphenoidal fissure to the apex of the petrous por-
tion of the temporal bone ; they receive anteriorly the ophthalmic vein through
the sphenoidal fissure, and communicate behind with the petrosal sinuses, and
with each other by the circular and transverse sinuses. On the inner wall of
each sinus is found the internal corotid artery, accompanied by filaments of the
carotid plexus and by the sixth nerve; and on its outer wall, the third, fourth,
and ophthalmic nerves. These parts are separated from the blood flowing along
the sinus by the lining membrane, which is continuous with the outer coat of
the veins. The cavity of the sinus, which is larger behind than in front, is
intersected by filaments of fibrous tissue and small vessels. The cavernous
sinuses receive the inferior anterior cerebral veins; they communicate with the
lateral sinuses by means of the superior and inferior petrosal, and with the facial
vein through the ophthalmic.
The ophthalmic is a large vein, which connects the frontal vein at the inner
angle of the orbit with tlic cavernous sinus; it pursues the same course as the
ophthalmic artery, and receives branches corresponding to those derived from
that vessel. Forming a short single trunk, it passes through the inner extremity
of the sphenoidal fissure, and terminates in the cavernous sinus.
The Circular Sinus completely surrounds the pituitary body, and communi-
cates on each side with the cavernous sinus. Its posterior lialf is larger than
the anterior; and in old age it is more capacious than at an early period of life.
It receives veins from the pituitary body, and from the adjacent bone and dura
mater.
OF THE UPPER EXTREMITY.
573
The Inferior Petrosal Sinus is situated in the groove formed bj the junction
of the inferior border of the petrous portion of the temporal witli the basilar pro-
cess of the occipital. It commences in front at the termination of the cavernous
sinus, and opens behind into the jugular foramen, forming with the lateral sinus
the commencement of the internal jugular vein. These sinuses are semi-cylindri-
cal in form.
Fig. 336.— The Sinuses at the Base of the Skull.
XjoT*;
The Transverse Sinus is placed transversely across the fore part of the basilar
process of the occipital bone serving to connect the two inferior petrosal and
cavernous sinuses. A second is occasionally found opposite the foramen
magnum.
The Superior Petrosal Sinus is situated along the upper border of the petrous
portion of the temporal bone, in the front part of the attached margin of the
tentorium. It is small and narrow, and connects together the cavernous and
lateral sinuses at each side. It receives a cerebral vein (anterior lateral cere-
bellar) from the anterior border of the cerebellum, a vein from the internal ear,
and sometimes a cerebral vein (inferior lateral cerebral) from the under part of
the middle lobe.
VEINS OF THE UPPER EXTREMITY.
The Veins of the Upper Extremity are divided into two sets, superficial and
deep.
The Superficial Veins are placed immediately beneath the integument be-
tween the two layers of superficial fascia ; they commence in the hand chiefly
on its dorsal aspect, where they form a more or less complete arch.
The Deep Veins accompany the arteries and constitute the vena? comites of
those vessels.
Both sets of vessels are provided with valves which are more numerous in
the deep than in the superficial.
574
VEINS.
Fig. 337.— The Superficial Yeins of the
Upper Extremity.
The superficial veins of the upper ex-
tremity are the
Anterior ulnar.
Posterior ulnar.
Basilic.
Eaclial.
^ttia^eoasJVerve
Cephalic.
Median.
Median basilic.
Median cephalic.
The Anterior Ulnar Vein commences on
the anterior surface of the ulnar side of
the hand and wrist, and ascends along the
inner side of the forearm to the bend of
the elbow, where it joins with the pos-
terior ulnar vein to form the basilic. It
communicates with branches of the median
vein in front, and with the posterior ulnar
behind.
The Posterior Ulnar Vein commences on
the posterior surface of the ulnar side of
the hand, and from the vein of the little
finger (vena salvatella), situated over the
fourth metacarpal space. It runs on the
posterior surface of the ulnar side of the
forearm, and just below the elbow unites
with the anterior ulnar vein to form the
basilic.
The Basilic is a vein of considerable
size, formed by the coalescence of the an-
terior and posterior ulnar veins. It is
situated along the inner side of the elbow,
receives the median basilac vein, and pass-
ing upwards along the inner side of the arm
pierces the deep fascia, and ascends in the
course of the brachial artery, terminating
either in one of the vense comites of that
vessel, or in the axillary vein.
The Radial Vein commences from the
dorsal surface of the thumb, index finger,
and radial side of the hand, by branches
communicating with the vena salvatella,
and forming by their union a large vessel,
which ascends along the radial side of the
forearm, and receives numerous branches
from both its surfaces. ■ At the bend of the
elbow it receives the median cephalic,
when it becomes the cephalic vein.
The Cephalic Vein courses along the
outer border of the Biceps muscle, to the
upper til ird of the arm; it then passes in
the interval between the Pectoralis major
and Deltoid muscles, accompanied by the
descending branch of the thoracio-acromi-
alis artery and the upper external cutane-
ous branch of the musculo -spiral nerve,
and terminates in the axillary vein just
below the clavicle. This vein is occasionally connected with the external jugular
or subclavian, by a branch which passes from it upwards in front of the clavicle.
The Median Vein collects the blood from the superficial structures on the palmar
AXILLARY. 575
surface of tlie hand and middle line of the forearm, communicating with the
anterior ulnar and radial veins. At the bend of the elbow, it receives a branch
of communication from the deep veins, accompanying the brachial artery and
divides into two branches, the median cephalic and median basilic, which diverge
from each other as they ascend.
The Median Cephalic, usually the smaller of the two, passes outwards in the
groove between the Supinator longus and Biceps muscles, and joins with the
cephalic vein. The branches of the external cutaneous nerve pass behind this
vessel.
The Median Basilic vein passes obliquely inwards, in the groove between the
Biceps and Pronator radii teres, and joins with the basilic. This vein passes in
front of the brachial artery, from which it is separated by a fibrous expansion
(the bicipital fascia) which is given off from the tendon of the Biceps to the
fascia covering the Flexor muscles of the forearm. Filaments of the internal
cutaneous nerve pass in front as well as behind this vessel.^
The Deep Veins of the upper extremity follow the course of the arteries, forming
their venee comites. They are generally two in number, one lying on each side
of the corresponding artery, and they are connected at intervals by short trans-
verse branches.
There are two digital veins, accompanying each artery along the sides of the
fingers ; these, uniting at their base, pass along the interosseous spaces in the
palm, and terminat3 in the two superficial palmar veins. Branches from these
vessels on the radial side of the hand accompany the superficialis volte, and on
the ulnar side terminate in the deep ulnar veins. The deep ulnar veins, as they
pass in front of the wrist, communicate with the interosseous and superficial
veins, and unite, at the elbow, with the deep radial veins, to form the vense co-
mites of the brachial artery.
The Interosseous Veins accompany the anterior and posterior interosseous
arteries. The anterior interosseous veins commence in front of the wrist, where
they communicate with the deep radial and ulnar veins ; at the upper part of
the forearm they receive the posterior interosseous veins, and terminate in the
venjB comites of the ulnar artery.
The Deep) Palmar Veins accompany the deep palmar arch, being formed by
branches which accompany the ramifications of that vessel. They communicate
with the superficial palmar veins at the inner side of the hand ; and on the outer
side terminate in the vense comites of the radial artery. At the wrist, they
receive a dorsal and a palmar branch from the thumb, and unite with the deep
radial veins. Accompanying the radial artery, these vessels terminate in the
ven* comites of the brachial artery.
The brachial veins are placed one on each side of the brachial artery, receiving
branches corresponding with those given off from that vessel ; at the lower
margin of the axilla they unite with the basilic to form the axillary vein.
The deep veins have numerous anastomoses, not only with each other, but
also with the superficial veins.
The AxiLLAEY Yei2^ is of large size and formed by the continuation upwards
of the basilic vein. It commences at the lower part of the axillary space,
increases in size as it ascends, by receiving branches corresponding with those
of the axillary artery, and terminates immediately beneath the clavicle at the
outer margin of the first rib, where it becomes the subclavian vein. This vessel
is covered in front by the Pectoral muscles and costo-coracoid membrane, and
lies on the thoracic side of tlie axillary artery. Opposite the subscapularis,
' Cruveilhier says : " Numerous varieties are observed in the disposition of the veins of the
elbow- sometimes the common median vein is wanting; but in those cases, its two branches of
bifurcation are furnished by the radial vein, and the cephalic is almost always in a rudimentary
condition. In other cases, only two veins are found at the bend of the elbow, the radial and ulnar,
which are continuous, without any demarcatioa, with the cephalic and basilic."
576 VEINS.
it is joined by a large vein, formed by tlie junction of the venje comites of tbe
brachial ; and near its termination it receives the cephalic vein. This vein is
provided with a pair of valves, opposite the lower border of the snbscapularis
muscle ; valves are also found at the termination of the cephalic and subscapu-
lar veins.
The Subclavian Yeix, the continuation of the axillary, extends from the
outer margin of the first rib to the inner end of the sterno-clavicular articulation,
where it unites with the internal jugular, to form the vena innominata. It is in
relation in front, with the clavicle and Subclavius muscle ; behind, with the
subclavian artery, from which it is separated internally by the Scalenus anticus
and phrenic nerve. Below, it rests in a depression on the first rib and upon the
pleura. Above, it is covered by the cervical fascia and integument.
The subclavian vein occasionally rises in the neck to a level with the third
part of the subclavian artery, and in two instances has been seen passing with
this vessel behind the scalenus anticus. This vessel is provided with valves
about an inch from its termination in the innominate, just external to the
entrance of the external jugular vein.
Branches. It receives the external and anterior jugular veins and a small
branch from the cephalic, outside the Scalenus ; and on the inner side of that
muscle, the internal jugular vein.
The Yexje Innominate (Fig. 338) are two large trunks, placed one on each
side of the root of the neck, and formed by the union of the internal jugular
and subclavian veins of the corresponding side.
The Ri(jlit Vena Innominata is a short vessel, about an inch and a half in
length, which commences at the inner end of the clavicle, and, passing almost
vertically downwards, joins with the left vena innominata just below the carti-
lage of the first rib, to form the superior vena cava. It lies superficial and
external to the arteria innominata ; on its right side the pleura is interposed
between it and the apex of the lung. This vein, at its angle of junction with
the subclavian, receives the right vertebral vein, and right Ijnnphatic duct ; and,
lower down, the right internal mammary, right inferior thyroid, and right supe-
rior intercostal veins.
The Left Vena Innominata^ about three inches in length, and larger than the
right, passes obliquely from left to right across the upper and front part of the
chest, to unite with its fellow of the opposite side, forming the superior vena
cava. It is in relation, in front, with the sternal end of the clavicle, the sterno-
clavicular articulation, and the first piece of the sternum, from which it is
separated by the Sterno-hyoid and Sterno-thyroid muscles, the thymus gland or
its remains, and some loose areolar tissue. Behind, it lies across the roots of the
three large arteries arising from the arch of the aorta. This vessel is joined by
the left vertebral, left inferior thyroid, left internal mammary, and the left supe-
rior intercostal veins, and occasionally some thymic and pericardiac veins. There
are no valves in the vense innorainataa.
Peculiarities. Sometimes the innominate veins open separately into the right auricle ; in anch
cases the rij^-ht vein takes the ordinary course of the superior vena cava, but the left vein, after
communicating l)y a small branch with the right one, passes in front of the root of the left lung,
and turning to the back of llie heart, receives the cardiac veins, and terminates in the back of the -
right auricle. This occasional condition of the veins in the adult, is a regular one in tlie foetus
at an early pcriwl, and the two vessels are persistent in birds and some mammalia. 'I'he subse-
quent changes which take place in these vessels are the following : 'I'iie communicating branch
between the two trunks enkirges and forms the future left innominate vein ; the remaining part
of the left trunk is obliterated as far as the heart, where it remains pervious, and forms the coro-
nary sinus; a remnant of the obliterated vessel is seen in adult life as a fibrous band passing
along the back of tlie left auricle and in front of tlie root of the left lung, called by Mr. Marshall
the vestigial folds of the pericardium.
The internal mummxtry veins, two in number to each artery, follow the course
of that vessel, and receive branches corresponding with those derived from it.
SUPERIOR VENA CAVA.
577
Fig. 338. — The Venae Cavse and Azygos Veins with
their Formative Brauciies.
Supe fioi- 77iuroid
■val Juc/vlar
Tke two veins of eacli side
unite into a single trunk,
wliicbi terminates in tke inno-
minate vein.
Tlie inferior thyroid veins,
two, frequently three or four
in number, arise in tlie venous
plexus on the thyroid body,
communicating with the mid-
dle and superior thyroid
veins. The left one descends
in front of the trachea, behind
the Sterno-thyroid muscles,
communicating with its fel-
low by transverse branches,
and terminates in the left
vena innominata. The right
one, which is placed a little
to the right of the median
line, opens into the right
vena innominata, just at its
junction with the superior
cava. These veins receive
tracheal and inferior laryngeal
branches, and are provided
with valves at their termina-
tion in the innominate veins.
The Superior Intercostal
Veins return the blood from
the upper intercostal spaces.
The right superior inter-
costal, much smaller than the
left, closely corresponds with
the superior intercostal artery,
receiving the blood from the
first, or first and second inter-
costal spaces, and terminates
in the right vena innominata.
Sometimes it passes down,
and opens into the vena azy-
gos major.
The left superior intercostal
is always larger than the
right, but varies in size in
different subjects, being small
when the upper azygos vein
is large, and vice versa. It is
usually formed by branches
from the two or three upper
intercostal spaces, and, pass-
ing across the arch of the
aorta, terminates in the left
vena innominata. The left
bronchial vein opens into it.
The SuPERiOE Vena Cava receives the blood which is conveyed to the heart
from the whole of the upper half of the body. It is a short trunk, varying from
two inches and a half to three inches in lenoth, formed by the iunction of the
37 o , J J
Renal
578 VEINS.
two yenvQ innominatse. It commences immediately below tlie cartilage of the
first rib on the right side, and descending vertically, enters the pericardium
about an inch and a half above the heart, and terminates in the upper part
of the right auricle. In its course, it describes a slight curve, the convexity of
which is turned to the right side.
ReMtions. In front^ with the thoracic fascia, which separates it from the
thymus gland, and from the sternum; behind^ with the root of the right lung.
On its riyht side^ with the phrenic nerve and right pleura ; on its left side, with
the ascending part of the aorta. The portion contained within the pericardium
is covered by the serous layer of that membrane, in its anterior three-fourths.
It receives the vena azygos major, just before it enters the pericardium, and
several small veins from the pericardium and parts in the mediastinum. The
superior vena cava has no valves.
The Azygos Yeins connect together the superior and inferior venge cava3,
supplying the place of those vessels in the part of the chest which is occupied
by the heart.
The larger, or right azygos vein, commences opposite the first or second lumbar
vertebra, by a branch from the right lumbar veins; sometimes by a branch from
the renal vein, or from the inferior vena cava. It enters the thorax through the
aortic opening in the Diaphragm, and passes along the right side of the vertebral
column to the third dorsal vertebra, where it arches forward over the root of
the right lung, and terminates in the superior vena cava, just before that vessel
enters the pericardium. Whilst passing through the aortic opening of the
Diaphragm, it lies with the thoracic duct on the right side of the aorta; and in
the thorax, it lies upon the intercostal arteries, on the right side of the aorta
and thoracic duct, covered by the pleura."
Branches. It receives nine or ten lower intercostal veins of the right side,
the vena azygos minor, several oesophageal, mediastinal, and vertebral veins;
near its termination, the right bronchial vein; and is occasionally connected
with the right superior intercostal vein. A few imperfect valves are found in
this vein ; but its branches are provided with complete valves.
The intercostal veins on the left side, below the two or three upper intercostal
spaces, usually form two trunks, named the left lower, and the left upper, azygos
veins.
The hft lower, or sm.aller azygos vein, commences in the lumbar region, by a
branch from one of the lumbar veins, or from the loft renal. It passes into the
thorax, through the left crus of the Diaphragm, and, ascending on the left side
of the spine, as high as the sixth or seventh dorsal vertebra, passes across the
column, behind the aorta and thoracic duct, to terminate in the right azygos
vein. It receives the four or five lower intercostal veins of the left side, and
some oesophageal and mediastinal veins.
The left npper azygos vein varies according to the size of the left superior
intercostal. It receives veins from the intercostal spaces between the left supe-
rior intercostal vein, and highest branch of the left lower azygos. They are
usually two or three in number, and join to form a trunk, which ends in the
right azygos vein, or in the left lower azygos. When this vein is small, or
altogether wanting, the left superior intercostal vein will extend as low as the
fifth or sixth intercostal space.
The hronrJdal veins return the blood from the substance of the lungs; that of
tlie riglit side opens into the vena azygos major, near its termination; that of
the left side, into the left superior intercostal vein.
The Spinal Veins.
The numerous venous y)lcxuses placed upon and wilhin ihe s])ine may be
arranged into four sots.
1. Those placed on tlie exterior of the spinal column (ihc dorsi-spinal veins).
SPINAL. 579
2. Those situated in the interior of the spinal canal, between the vertebrge
and the theca vertebralis (meningo-rachidian veins),
3. The veins of the bodies of the vertebrse.
4. The veins of the spinal cord (medulli-spinal).
1. The Dorsi-spinal Veins commence by small branches, which receive their
blood from the integument of the back of the spine, and from the muscles in
the vertebral grooves. They form a complicated network, which surrounds
the spinous processes, the laminae, and the transverse and articular processes of
all the vertebrge. At the basis of the transverse processes, they communicate,
by means of ascending and descending branches, with the veins surrounding
the contiguous vertebrae, and they join with the veins in the spinal canal by
branches which perforate the ligamenta subflava; they terminate in the intervals
between the arches of the vertebra, by joining the vertebral veins in the neck,
the intercostal veins in the thorax, and the lumbar and sacral veins in the loins
and pelvis.
2. Tlie principal veins contained in the spinal canal are situated between the
theca vertebralis and the vertebrae. They consist of two longitudinal plexuses,
one of which runs along the posterior surface of the bodies of the vertebrae
throughout the entire length of the spinal canal (anterior longitudinal spinal
veins), receiving the veins belonging to the bodies of the vertebrge (ven» basis
vertebrarum). The other plexus (posterior longitiidinal spinal veins) is placed
on the inner, or anterior surface of the lamina of the vertebrge, and extends
also along the entire length of the spinal canal.
The Anterior Longitudinal S^jinal Veins consist of two large, tortuous, venous
canals, which extend along the whole length of the vertebral column, from the
foramen magnum to the base of the coccyx, being placed one on each side of
the posterior surface of the bodies of the vertebras, external to the posterior
common ligament. These veins communicate together opposite each vertebra,
by transverse trunks, which pass beneath the ligament, and receive the largo
venjB basis vertebrarum, from the interior of the body of each vertebra. The
anterior longitudinal spinal veins are least developed in the cervical and sacral
regions. They are not of uniform size throughout, being alternately enlarged
and constricted. At the intervertebral foramina, they communicate with the
dorsi-spinal veins, and with the vertebral veins in the neck, with the intercostal
veins in the dorsal region, and with the lumbar and sacral veins in the corre-
sponding regions.
The Posterior Longitudinal SpinalVeins^ smaller than the anterior, are situated
one on either side, between the inner surface of the laminae and the theca verte-
bralis. They communicate (like the anterior), opposite each vertebra, by trans-
verse trunks; and with the anterior longitudinal veins, by lateral transverse
branches, Avhich pass from behind forwards. These veins, at the intervertebral
foramina, join with the dorsi-spinal veins.
3. The Veins of the Bodies of the Vertebrae (venae basis vertebrarum) emerge
from the foramina on their posterior surface, and join the Iransverse trunk
connecting the anterior longitudinal spinal veins. They are contained in large
tortuous channels, in the substance of the bones, similar in every respect to those
found in the diploe of the cranial bones. These canals lie parallel to the upper
and lower surface of the bones, arise from the entire circumference of the
vertebra, communicate with veins which enter through the foramina on the
anterior surface of the bodies, and converge to the principal canal, which is
sometimes double towards its posterior part. They become greatly developed
in advanced age.
4. The Veins of the Spinal Cord (medulli-spinal) consist of a minute tortuous
venous plexus which covers the entire surface of the cord, being situated between
the pia mater and arachnoid. These vessels emerge chiefly from the posterior
median furrow, and are largest in the lumbar region. Near the base of the
580
VEINS.
skull they "anite, and form two or three small trunks, wliick communicate with,
the vertebral veins, and then terminate in the inferior cerebellar veins, or in the
Fig. 339. — Transverse Section of a Dorsal Vertebra, showing the Spinal Veins.
sr ' -.
Fig. 340.— Vertical Section of two Dorsal Vertebrse, showing the Spinal Veins.
petrosal sinuses. Each of the spinal nerves is accompanied by a branch as far
as the inter- vertebral foramina, where they join the other veins from the spinal
canal.
There are no valves in the spinal veins.
VEINS OF THE LOWEE EXTEEMITY.
The Veins of the Lower Extremity are subdivided, like lliosc of the upper,
into two sets, superficial and deep; the superficial veins being placed beneath
tlic integument, between the two layers of su])erficial fascia; the deep veins
accompanying the arteries, and forming the vcnas comites of those vessels.
Both sets of veins are provided with valves, which are more numerous in the
deep than in the superficial set. These valves are also more numerous in the
lower than in the upper limb.
The t^Uiperfic'ial Veins of tlio lower extroinity arc the internal or long saphe-
nous, and the external or sliort saplienous.
OF THE LOWER EXTREMITY.
581
I
The internal saphenous vein (Fig. 341) commences Fig- 341.— The Internal or
from a minute plexus, which covers the dorsum and Long Saphenous Vein and its
inner side of the foot; it ascends in front of the inner
ankle, and along the inner side of the leg, behind the » ^
inner margin of the tibia, accompanied by the inter-
nal saphenous nerve. At the knee, it passes back-
wards behind the inner condyle of the femur, ascends
along the inside of the thigh, and passing through
the saphenous opening in the fascia lata, terminates
in the femoral vein about an inch and a half below
Poupart's ligament. This vein receives in its course
cutaneous branches from the leg and thigh, and at
the saphenous opening the superficial epigastric, su-
perficial circumflex iliac, and external pudic veins.
The veins from the inner and back part of the thigh
frequently unite to form a large vessel, which enters
the main trunk near the saphenoQS opening ; and
sometimes those on the outer side of the thigh join
to form a large branch ; so that occasionally three
large veins are seen converging from different parts of
the thigh towards the saphenous opening. The in-
ternal saphenous vein communicates in the foot with
the internal plantar vein ; in the leg, with the pos-
terior tibial veins, by branches which perforate the
tibial origin of the Soleus muscle, and also with the
anterior tibial veins ; at the knee, with the articular
veins ; in the tliigh, with the femoral vein by one or
more branches. The valves in this vein vary from
two to six in number ; they are more numerous in
the thio-h than in the lesr.
The external or sliort saphenous vein (Fig. 342) is
formed by branches which collect the blood from the
dorsum and outer side of the foot ; it ascends behind
the outer ankle, and along the outer border of the
tendo Achillis, across which it passes at an acute
angle to reach the middle line of the posterior aspect
of the leg. Passing directly upwards, it perforates
the deep fascia in the lower part of the popliteal space,
and terminates in the popliteal vein, between the
heads of the Gastrocnemius muscle. It is accompa-
nied by the external saphenous nerve. It receives
numerous large branches from the back part of the
leg, and communicates with the deep veins on the
dorsum of the foot, and behind the outer malleolus.
This vein has only two valves, one of which is always
found near its termination in the popliteal vein.
The Deep Veins of the lower extremity accompany
the arteries and their branches, and are called the
veyire comites of those vessels.
The external and internal plantar veins unite to
form the posterior tibial. They accompany the
posterior tibial artery, and are joined by the pero-
neal veins.
The anterior tibial veins are formed by a continuation upwards of the vente
comites of the dorsalis pedis artery. They perforate the interosseous mem-
brane at the upper part of the leg, and form, by their junction with the posterior
tibial, the popliteal vein.
582
VEINS.
Fig. 342.— Exter-
i)al or Short Saphe-
nous Vein.
'I.
'^/
~/
'nh
The valves in tlie deep veins are very numerous.
Tlie Popliteal YeIjST is formed by the junction of the venee comites of the
anterior and posterior tibial vessels ; it ascends through the
popliteal space to the tendinous aperture in the Adductor
magnus, where it becomes the femoral vein. In the lower
part of its course, it is placed internal to the artery ; between
the heads of the Gastrocnemius, it is superficial to that
vessel; but above the knee-joint, it is close to its outer side.
It receives the sural veins from the Gastrocnemius muscle,
the articular veins, and the external saphenous. The valves
in this vein are usually four in number.
The Femoral Vein accompanies the femoral artery
through the upper two-thirds of the thigh. In the lower
part of its course, it lies external to the artery ; higher up,
it is behind it; and beneath Poupart's ligament, it lies to its
inner side, and on the same plan. It receives numerous
muscular branches ; the profunda femoris joins it about an
inch and a half below Poupart's ligament, and near its termi-
nation the internal saphenous vein. The valves in this vein
are four or five in number.
The External Iliac Vein commences at the termination
of the femoral, beneath the crural arch, and passing upwards
along the brim of the pelvis, terminates opposite the sacro-
iliac symphysis, by uniting with the internal iliac to form
the common iliac vein. On the right side, it lies at first
along the inner side of the external iliac artery; but as it
passes upwards, gradually inclines behind it. On the left
side, it lies altogether on the inner side of the artery. It,
receives, immediately above Poupart's ligament, the ejDi-
gastric and circumflex iliac veins. It has no valves.
The Internal Iliac Vein is formed by the vena3 comites
of the branches of the internal iliac artery, the umbilical
arteries excepted. It receives the blood from the exterior
of the pelvis by the gluteal, sciatic, internal pudic, and obtu-
rator veins ; and from the organs in the cavity of the pelvis
by the hemorrhoidal and vesico-prostatic plexuses in the
male, and the uterine and vaginal plexuses in the female.
The vessels forming these plexuses are remarkable for their
large size, their frequent anastomoses, and the number of
valves which they contain. The internal iliac vein lies at
first on the inner side and then behind the internal iliac artery, and terminates
(opposite the sacro-iliac articulation, by uniting with the external iliac, to form
the common iliac vein. This vessel has no valves.
The hemorrhoidal jylexus surrounds the lower end of the rectum, being formed
by the superior hemorrhoidal veins (branches of the inferior mesenteric), and the
middle and inferior hemorrhoidal, which terminate in the internal iliac. The
portal and general venous systems have a free communication by means of the
branches composing this plexus.
The vesi.co-'prostutic plexus surrounds the neck and base of the bladder and
prostate gland. It communicates with the hemorrhoidjil plexus behind, and
receives the dorsal vein of the penis, which enters the pelvis beneath the sub-
pubic ligament. This plexus is supported upon the sides of the bladder by a
reflection of the pelvic fascia. The veins composing it are very liable to become
varicose, and often contain hard earthy concretions, called phleholillis.
The dorsal vein of tJie 'jicnis is a vessel of large size, which returns the blood
from the body of that organ. At first it consists of two branch(!S, which are
contained in tlic groove on the dorsum of the penis, and it receives veins from
INFERIOR VENA CAVA. 583
tlie glans, tlie corpus spongiosum, and numerous superficial veins ; these unite
near the root of tlie penis into a single trunk, which pierces the triangular liga-
ment beneath the pubic arch, and divides into two branches, which enter the
prostatic plexus.
The vaginal plexus surrounds tlie mucous membrane, being especially de-
veloped at the orifice of the vagina ; it communicates with the vesical plexus
in front, and with the hemorrhoidal plexus behind.
The uterine plexus is situated along the sides and superior angles of the uterus,
receiving large venous canals (the uterine sinuses) from its su.bstance. The
veins composing this plexus anastomose frequently with each other and with
the ovarian veins. They are not tortuous like the arteries.
The Common Iliac Yeins are formed by the union of the external and internal
iliac veins in front of the sacro- vertebral articulation ; passing obliquely upwards
towards the right side, they terminate upon the intervertebral substance between
the fourth and fifth lumbar vertebrae, where the veins of the two sides unite at
an acute angle to form the inferior vena cava. The right common iliac is shorter
than the left, nearly vertical in its direction, and ascends behind and then to the
outer side of its corresponding artery. The left co7)%mon iliac^ longer and more
oblique in its course, is at first situated on the inner side of the corresponding
artery, and then behind the right common iliac. Each common iliac receives
the ilio-lumbar and sometimes the lateral sacral veins. The left receives, in
addition, the middle sacral vein. Ko valves are found in these veins.
The middle sacral vein accompanies its corresponding artery along tlie front
of the sacrum, and terminates in the left common iliac vein ; occasionally in the
commencement of the inferior vena cava.
Peculiarities. The left common iliac vein, instead of joining with the right in its visual posi-
tion, occasionally ascends on the left side of the aorta as high as the kidney, where, after receiv-
ing the left renal vein, it crosses over the aorta, and then joins with the right vein to form the
vena cava. In these cases, the two common iliacs are connected by a small communicating branch
at the spot where they are usually united.
The Inferior Vena Cava returns to the heart the blood from all the parts
below the Diaphragm. It is formed by the junction of the two common iliac
veins on the right side of the intervertebral substance between the fourth and
fifth lumbar vertebra. It passes upwards along the front of the spine, on the
right side of the aorta, and having reached the under surface of the liver, is
contained in a groove in its posterior border. It then perforates the tendinous
centre of the Diaphragm, enters the pericardium, where it is covered by its
serous layer, and terminates in the lower and back part of the right auricle. At
its termination in the auricle, it is provided with a valve, the Eustachian, which
is of large size during foetal life.
Relations. In 'front^ from below upwards, with the mesentery, transverse
portion of the duodenum, the pancreas, portal vein, and the posterior border of
the liver, which partly and occasionally completely surrounds it ; behind, with
the vertebral column, the right crus of the Diaphragm, the right renal and
lumbar arteries ; on the left side, with the aorta. It receives in its course the
following branches :
Lumbar. Suprarenal.
Eight spermatic. Phrenic.
Eenal. Hepatic.
Peculiarities. In Position. This vessel is sometimes placed on the left side of the aorta, as
high as the left renal vein, after receiving which, it crosses over to its usual position on the right
side ; or it may be placed altogether on the left side of the aorta, as far upwards as its termina-
tion in the heart : in such cases, the abdominal and tlioracic viscera, together with the great ves-
sels, are all transposed.
Point of Term/nation. Occasionally, the inferior vena cava joins the right azygos vein, which
is then of large size. In such cases, the superior cava receives the whole of the blood from the
body before transmitting it to the right auricle, except the blood from the hepatic veins, which
terminate directly in the right auricle.
584 VEINS.
Tlie lumbar veins^ three or four in number on eacli side, collect tlie blood by
dorsal branches from the muscles and integument of the loins, and by abdominal
branches from the walls of the abdomen, where they communicate with the
epigastric veins. At the spine, they receive branches from the sjjinal plexuses,
and then pass forwards round the sides of the bodies of the vertebrae beneath
the Psoas magnus, and terminate at the back part of the inferior cava. The
left lumbar veins are longer than the right, and pass behind the aorta. The
lumbar veins communicate with each other by branches which pass in front of
the transverse processes. Occasionally, two or more of these veins unite to form
a single trunk, the ascending lumbar, which serves to connect the common iliac,
ilio-lumbar, lumbar, and azygos veins of the corresponding side of the body.
The sperr)%atic veins emerge from the back of the testis, and receive branches
from the epididymis; they form a branched and convoluted plexus, called the
spermatic plexus (plexus pampiniformis), below the abdominal ring: the vessels
composing this plexus are very numerous, and ascend along the cord in front
of the vas deferens; having entered the abdomen, they coalesce to form two
branches, which ascend on the Psoas muscle, behind the peritoneum, lying one
on each side of the spermatic artery, and unite to form a single vessel, which
opens on the right side in the inferior vena cava, at an acute angle, on the left
side in the left renal vein, at a right angle. The spermatic veins are provided
with valves. The left spermatic vein passes behind the sigmoid flexure of the
colon, a part of the intestine in which fascal accumulation is common ; this cir-
cumstance, as well as the indirect communication of the vessel with the inferior
vena cava, may serve to explain the more frequent occurrence of varicocele on
the left side.
The ovarian veins are analogous to the spermatic in the male; they form a
plexus near the ovary, and in the broad ligament and Fallopian tube, communi-
cating with the uterine plexus. They terminate as in the male. Valves are
occasionally found in these veins. These vessels, like the uterine veins, become
much enlarged during pregnancy.
The renal veins are of large size, and placed in front of the renal arteries.^
The left is longer than the right, and passes in front of the aorta, just below the
origin of the superior mesenteric artery. It receives the left spermatic and left
inferior phrenic veins. It usually opens into the vena cava, a little higher than
the right.
The suprarenal vein terminates, on the right side, in the vena cava; on the
left side, in the left renal or phrenic vein.
The pjJirenic veins follow the course of the phrenic arteries. The tvo superior,
of small size, accompany the phrenic nerve and comes nervi phrenici artery ;
the right terminating opposite the junction of the two vense innominatas', the
left in the left superior intercostal or left internal mammary. The tivo inferior
phrenic veins follow the course of the phrenic arteries, and terminate, the right
in the inferior vena cava, the left in the left renal vein.
The hepatic veins commence in the substance of the liver, in the capillary
terminations of the vena portoe: these branches, gradually uniting, form three
large veins, which converge towards the posterior border of the liver, and open
into the inferior vena cava, whilst that vessel is situated in the groove at the
back part of this organ. Of these three veins, one from the right, and another
from the left lobe, open obliquely into the vena cava ; that from the middle of
the organ and lobulus Spigelii having a straight course. The hepatic veins run
singly, ajid are in direct contact with the hepatic tissue. They are destitute of
valves.
' TIic slmlcnl may ohsorvo iliiit. :ill veins nliovo tlio Diaplirapm, wliicli do not lio on llie same
piano as llie iirtoric'H wliicli tlicj' accomijuny, lie in front of llicni; and lliat, all veins below the
Diaphrafrm, wliicli do not lie on llie same planet as the arteries wliicli they accompany, lie behind
them, except the renal and prolunda lemoris vein.
PORTAL SYSTEM. 585
Portal System of Yeins.
Tlie Portal Venous System is composed of four large veins, wliicli collect tlie
venous blood from tlie viscera of digestion. The trunk formed by their union
(vena portas) enters the liver and ramifies throughout its substance; and its
branches again emerging from that organ as the hepatic veins terminate in the
inferior vena cava. The branches of this vein are in all cases single, and desti-
tute of valves.
The veins forming the portal system are, the
Inferior mesenteric. Splenic.
Superior mesenteric. Gastric.
The inferior mesenteric vein returns the blood from the rectum, sigmoid flex-
ure, and descending colon, corresponding with the ramifications of the branches
of the inferior mesenteric artery. Ascending beneath the peritoneum in the
lumbar region, it passes behind the transverse portion of the duodenum and
pancreas, and terminates in the splenic vein. Its hemorrhoidal branches inos-
culate with those of the internal iliac, and thus establish a communication
between the portal and the general venous system.^
The superior mesenteric vein returns the blood from the small intestines, and
from the ceecum and ascending and transverse portions of the colon, correspond-
ing with the distribution of the branches of the superior mesenteric artery.
The large trunk formed by the union of these branches ascends along the right
side and in front of the corresponding artery, passes in front of the transverse
portion of the duodenum, and unites behind the upper border of the pancreas
with the splenic vein to form the vena portas. It receives the right gastro-
epiploic vein.
The splenic vein commences by five or six large branches, which return the
blood from the substance of the spleen. These uniting form a single vessel,
which passes from left to right behind the upper border of the pancreas, and
terminates at its greater end by uniting at a right angle with the superior
mesenteric to form the vena portse. The splenic vein is of large size, and not
tortuous like the artery. It receives the vasa brevia from the left extremity of
the stomach, the left gastro-epiploic vein, pancreatic branches from the pancreas,
the pancreatico-duodenal vein, and the inferior mesenteric vein.
The gastric is a vein of small size, which accompanies the gastric artery from
left to right along the lesser curvature of the stomach, and terminates in the vena
portae.
The Portal Vein is formed by the junction of the superior mesenteric and
splenic veins, their union taking place in front of the vena cava, and behind the
upper border of the great end of the pancreas. Passing upwards through the
right border of the lesser omentum to the under surface of the liver, it enters
the transverse fissure, where it is somewhat enlarged, forming the sinus of the
portal vein, and divides into two branches, which accompany the ramifications
of the hepatic artery and hepatic duct throughout the substance of the liver.
Of these two branches the right is the larger but the shorter of the two. The
portal vein is about four inches in length, and, whilst contained in the lesser
omentum, lies behind and between the hepatic duct and artery, the former being
to the right, the latter to the left. These structures are accompanied by fila-
ments of the hepatic plexus of nerves, and numerous lymphatics, surrounded by
a quantity of loose areolar tissue (capsule of Glisson), and placed between the
' Besides this anastomosis between the portal vein and the branches of the vena cava, other
anastomoses between the portal and systemic veins are formed by the communication between the
left renal vein and the veins of the intestines, especially of the colon and duodenum, and between
superficial branches of the portal veins of the liver and the phrenic veins, as pointed out by Mr.
Kiernan (Todd and Bowman).
586
VEINS.
layers of tlie lesser omentum. Tlie vena portte receives the gastric and cystic
veins ; the latter vein sometimes terminates in tlie riglit branch of the vena
Fig. 343.— Portal Vein and its Branches.
portoe. Within the liver the j)ortal vein receives the blood from the branches
of the hepatic artery.
Cardiac Yeins.
The veins which return the blood from tlic substance of the heart arc, the
Great cardiac vein. Anterior cardiac veins.
Posterior cardiac vein. Venaj Thcbcsii.
The Great Cardiac Vein is a vessel of considerable size, which commences at
the apex of the heart, and ascends along the anterior interventricular groove to
the base of the ventricles. It then curves to the left side, around the auriculo-
vcntricular groove, between the left auricle and ventricle, to the back part of
the heart, and opens into the coronary sinus, its aperture being guarded by two
PULMONARY. 587
valves. It receives tlie posterior cardiac vein, and the left cardiac veins from
the left auricle and ventricle, one of which, ascending along the left margin of
the ventricle, is of large size. The branches joining it are provided with
valves.
The Posterior Cardiac Vein commences, by small branches, at the apex of the
heart, communicating with those of the preceding. It ascends along the poste-
rior interventricular groove to the base of the heart, and terminates in the coro-
nary sinus, its orifice being guarded by a valve. It receives the veins from the
posterior surface- of both ventricles.
The Anterior Cardiac Veins are three or four small branches, which collect
the blood from the anterior surface of the right ventricle. One of these (the
vein of Galen), larger than the rest, runs along the right border of the heart.
They open separately into the lower part of the right auricle.
The Venis Thehesii are numerous minute veins, which return the blood
directly from the muscular substance, without entering the venous current.
They open by minute orifices (^foramina Thebesii), on the inner surface of the
right auricle.
The Coronary Sinus is that portion of the great cardiac vein which is situated
in the posterior part of the left auriculo-ventricular groove. It is about an inch
in length, presents a considerable dilatation, and is covered by the muscular fibres
of the left auricle. It receives the great cardiac vein, the posterior cardiac vein,
and an oblique vein from the back part of the left auricle, the remnant of the
obliterated left innominate trunk of the foetus, described by Mr. Marshall. The
coronary sinus terminates in the right auricle, between the inferior vena cava
and the auriculo-ventricular aperture, its orifice being guarded by a semilunar
fold of the lining membrane of the heart, the coronary valve. All the branches
joining this vessel, excepting the oblique vein above mentioned, are provided
with valves.
The Pulmonary Veins.
The Pulmonary Veins return the arterial blood from the lungs to the left
auricle of the heart. They are four in number, two for each lung. The
pulmonary differ from other veins in several respects : 1. They carry arterial
instead of venous blood. 2. They are destitute of valves. 3. They are only
slightly larger than the arteries they accompany. 4. They accompany those
vessels singly. They commence in a capillary network, upon the parietes of the
bronchial cells, where they are continuous with the ramifications of the pul-
monary artery, and, uniting together, form a single trunk for each lobule. These
branches, uniting successively, form a single trunk for each lobe, three for the
right, and two for the left lung. The vein from the middle lobe of the right
lung unites with that from the upper lobe, in most cases, forming two trunks
on each side, which open separately into the left auricle. Occasionally, they
remain separate ; there are then three veins on the right side. Not unfrequently,
the two left pulmonary veins terminate by a common opening.
Within the lung^ the branches of the pulmonary artery are in front^ the veins
behind, and the bronchi between the two.
At the root of the lung, the veins are in front, the artery in the middle, and the
bronchus behind.
Within the pericarddum, their anterior surface is invested by the serous layer
of this membrane. ' The right pulmonary veins pass behind the right auricle
and ascending aorta; the left pass in front of the thoracic aorta, with the left
pulmonary artery.
Of the Lymphatics.
The Ljmpliatics have derived tlieir name from the appearance of the fluid
contained in tlieir interior {Jympha, water). They are also called absorbents,
from the property they possess of absorbing certain materials from the tissues,
and conveying them into the circulation.
The lymphatic system includes not only the lymphatic vessels and the glands
through which they pass, but also the lacteal, or chyliferous vessels. The lac-
teals are the lymphatic vessels of the small intestine, and differ in no respect
from the lymphatics generally, excepting that they contain a milk-white fluid,
the chyle, during the process of digestion, and convey it into the blood through
the thoracic duct.
The lymphatics are exceedingly delicate vessels, the coats of which are so
transparent, that the fluid they contain is readily seen through them. They
retain a nearly uniform size, being interrupted at intervals by constrictions
which give them a knotted or beaded appearance. These constrictions are due
to the presence of valves in their interior. Lymphatics have been found in
nearly every texture and organ of the body, with the exception of the substance
of the brain and spinal cord, the eyeball, cartilage, tendon, the membranes of
the ovum, the placenta, and umbilical cord, the nails, cuticle, and hair. Their
existence in the substance of bone is doubtful.
The lymphatics are arranged into a superficial and deep set. The superficial
lymphatics, on the surface of the body, are placed immediately beneath the
integument, accompanying the superficial veins; they join the deep lymphatics
in certain situations by perforating the deep fascia. In the interior of the body,
they lie in the submucous areolar tissue, throughout the whole length of the
gastro-pulmonary and genito-urinary tracts ; and in the subserous areolar tissue
in the cranial, thoracic, and abdominal cavities. The method of their origin is
described along with the other details of their minute anatomy in the intro-
duction. Here it will be sufficient to say that a plexiform network of minute
lymphatics may be found interspersed among the proper elements and blood-
vessels of the several tissues; the vessels composing which, as well as the
meshes between them, are much larger, than those of the capillary plexus.
From these networks small vessels emerge, which pass, either to a neighboring
gland, or to join some larger lymphatic trunk. The deep lymphatics, fewer in
number, and larger than the superficial, accompany the deep bloodvessels.
Their mode of origin is not known; it is, however, probably, similar to that of
the superficial vessels. The lymphatics of any part or organ exceed the veins
in number; but in size they are much smaller. Their anastmoses also, espe-
cially those of the large trunks, are more frequent, and are eflccted by vessels
equal in diameter to those which they connect, the continuous trunks retaining
the same diameter.
The lymphatic or absorbent glands, named also conglobate glands, arc small
solid glandular bodies, situated in the course of the lyrnphatic and lacteal
vessels. They arc found in the neck and on the external ])arts of the head;
in the upper extremity, in the axilla and in front of the elbow; in the lower
extremity, in the groin and pojiliteal space. In the abdomen, they are found
in large numbers in the mesenlery, and along the side of the aorta, vena cava,
and iliac vessels; and in the thorax, in the anterior and posterior mediastina.
They arc somewhat flattened, and of a round or oval form. In size, they vary
from a hemp-seed to an almond, and their aAov, on section, is of a^ pinkish-gray
(588)
THORACIC DUCT.
589
tint, excepting tlie broncMal glands, wliicli in tlie adult are mottled witli black.
Each, gland has a layer, or capsule of cellular tissue investing it, from which
prolongations dip into its substance forming partitions. The lymphatic and
lacteal vessels pass through these bodies in their passage to the thoracic and
lymphatic ducts. A lymphatic or lacteal vessel, previous to entering a gland,
divides into several small branches which are named afferent vessels. As they
enter, their external coat becomes continuous with the capsule of the gland,
and the vessels, much thinned, and consisting only of their internal coat and
epithelium, pass into the gland,
where they subdivide and pursue Fig- 344.— The Thoracic and Right Lymphatic Duct.
a tortuous course ; and they finally
anastomose, so as to form a plexus.
The vessels composing this plexus
unite to form two or more efferent
vessels, which, on emerging from
the gland, are again invested with
their external coat. Further de-
tails on the minute anatomy of
the lymphatic vessels and glands
will be found in the Introduction.
Thoracic Duct.
The Thoracic Duct (Fig. 344)
conveys the great mass of the
lymph and chyle into the blood.
It is the common trunk of all the
lymphatic vessels of the body,
excepting those of the right side
of the head, neck, and thorax,
and right upper extremity, the
right lung, riD;ht side of the heart,
and the convex surface of the
liver. It varies from eighteen to
twenty inches in length in the
adult, and extends from the second
lumbar vertebra to the root of the
neck. It commences in the abdo-
men by a triangular dilatation,
the receptaculum chyli (reservoir
or cistern of Pecquet), which is
situated upon the front of the
body of the second lumbar verte-
bra, to the right side and behind
the aorta, by the side of the right
crus of the Diaphragm. It ascends
into the thorax throuarh the aortic
opening in the Diaphragm, and is
placed in the posterior medias-
tinum in front of the vertebral
column, lying between the aorta
and vena azygos. Opposite the
fourth dorsal vertebra, it inclines
towards the left side and ascends
behind the arch of the aorta, on
the left side of the oesophagus, and
behind the first portion of the left
UtimJja?' GFafitIt
590 LYMPHATICS.
subclavian artery to the npper orifice of tlie tliorax. Opposite the upper border
of tlie seventli cervical vertebra, it curves downwards above the subclavian
artery, and in front of the Scalenus anticus muscle, so as to form an arch; and
terminates near the angle of junction of the left internal jugular and subclavian
veins. The thoracic duct, at its commencement, is about equal in size to the
diameter of a goose-quill, diminishes considerably in its calibre in the middle of
the thorax, and is again dilated just before its termination. It is generally
flexuous in its course, and constricted at intervals, so as to present a varicose
appearance. The thoracic duct not infrequently divides in the middle of its
course into two branches of unequal size, which soon reunite, or into several
branches which form a plexiform interlacement. It occasionally bifurcates, at
its upper part, into two branches, of which the one on the left side terminates
in the usual manner, while that on the right opens into the right subclavian
vein in connection with the right lymphatic duct. The thoracic duct has
numerous valves throughout its whole course, but they are more numerous in
the upper than in the lower part; at its termination it is provided with a pair
of valves, the free borders of which are turned towards the vein, so as to
prevent the regurgitation of venous blood into the duct.
. Branches. The thoracic duct, at its commencement, receives four or five large
trunks from the abdominal lymphatic glands, and also the trunk of the lacteal
vessels. Within the thorax, it is joined by the lymphatic vessels from the left
half of the wall of the thoracic cavity, the lymphatics from the sternal and
intercostal glands, those of the left lung, left side of the heart, trachea, and
oesophagus; and just before its termination, receives the lymphatics of the left
side of the head and neck, and left upper extremity.
Structure. The thoracic duct is composed of three coats, which differ in some
respects from those of the lymphatic vessels. The internal coat consists of a
layer of epithelium, resting upon some striped lamellee, and an elastic fibrous
coat, the fibres of which run in a longitudinal direction. The middle coat
consists of a layer of connective tissue, beneath which are several laminas of
muscular tissue, the fibres of which are disposed transversely, and intermixed
with the elastic fibres. The external coat is composed of areolar tissue, with
elastic fibres and isolated fasciculi of muscular fibres.
The Right Lymphatic Duct is a short trunk, about an inch in length, and a
line or a line and a half in diameter, which receives the lymph from the right
side of the head and neck, the right upper extremity, the right side of the
thorax, the right lung and right side of the heart, and from the convex surface
of the liver, and terminates at the angle of union of the right subclavian and
right internal jugular veins. Its orifice is guarded by two semilunar valves,
which prevent the entrance of blood from the veins.
Lymphatics of the Head, Face, and ISTeck.
The Superficial Lymphatic Glands of the Head (Fig. 345) are of small size, few
in number, and confined to its posterior region. They are the occipital^ placed
at the back of the head along the attachment of the occipito-frontalis ; and the
posterior auricular^ near the upper end of the Sterno-mastoid. These glands are
affected in cutaneous eruptions and other diseases of the scalp. In the face, the
su|)crricial lymphatic glands arc more numerous: they are ilio, parotid^ some of
which arc superficial and others deeply placed in the substance of the parotid
gland; the zygomatic^ situated under the zygoma; the Imccal^ on the surface of
the Buccinator muscle; and the submaxillary, the largest, beneath the body of
the lower jaw.
Tlio su'perfieial lyrapliMics of tlie licad are divld('(l iiilo an anterior and a
posterior set, which follow the course of the tem])oral and occipital vessels.
Tlie temporal set accompany the temporal artery in front of tiie car, to the
parotid lymphulic glands, fV(;ni which llicy jirocced to the lyiiq)liatic glands of
OF THE HEAD, FACE, AND NECK.
'591
tlie neck. Tlie occipital set follow the course of the occipital artery, descend
to the occipital and posterior auricular lymphatic glands, and from thence join
the cervical glands.
The superficial lymphatics of the face are more numerous than those of the
head, and commence over its entire surface. Those from the frontal region
accompany the frontal vessels ; they then pass obliquely across the face, running
with the facial vein, pass through the buccal glands on the surface of the
Buccinator muscle, and join the submaxillary lymphatic glands. The latter
receive the lymphatic vessels from the lips, and are often found enlarged in
cases of malignant disease of those parts.
The deep lymphatics of the face are derived from the pituitary membrane of
the nose, the mucous membrane of the mouth and pharynx, and the contents of
the temporal and orbital fossas ; they accompany the branches of the internal
maxillary artery, and terminate in the deep parotid, and cervical lymphatic
glands.
The deep) lym^phatics of the cranium consist of two sets, the meningeal and
cerebral. The meningeal lymphatics accompany the meningeal vessels, escape
Fig. 345. — The Superficial Lymphatics and Glands of the Plead, Face, and Neck.
through foramina at the base of the skull, and join the deep cervical lymphatic
glands. The cerebral lymphatics are described by Eshmann as being situated
between the arachnoid and pia mater, as well as in the choroid plexuses of the
lateral ventricles; they accompany the trunks of the carotid and vertebral
592
LYMPHATICS.
arteries, and probably pass tlirougli foramina at tlie base of tbe skull, to terminate
in tbe deep cervical glands. They liave not at present been demonstrated in the
dura mater, or in the substance of tlie brain.
The Lymphatic Glands of the Neck are divided into two sets, superficial and
deep.
The superficial cervical glands are placed in the course of the external jugular
vein, between the Platysma and sterno-mastoid. They are most numerous at
the root of the neck, in the triangular interval between the clavicle, the sterno-
mastoid, and the Trapezius, where they are continuous with the axillary glands.
A few small glands are also found on the front and sides of the larynx.
The deep cervical glands (Fig. 346) are numerous and of large size ; they form
an uninterrupted chain along the sheath of the carotid artery and internal jugu-
lar vein, lying by the side of the phrarynx, oesophagus, and trachea, and extend-
ing from the base of the skull to the thorax, where they communicate with the
lymphatic glands in that cavity.
Fig. 346. — The Deep Ijymphatics and Glands of the Neck and Thorax.
^hc superficial amd deep cervical lyrnpliatics are a continuation of those al]'(\ady
described on the cranium and face. After traversing the glands in those regions,
they pass through the cliain of glands wliich lie along the sheath of the carotid
vessels, being joined by tlie lymplintics from the ]-)liarynx, oesophagus, larynx,
trachea, and thyroid gland. At lhc lower ));n-t of iJic neck, after receiving
OF THE UPPER EXTREMITY.
593
some lympliatics from the thorax, tliey unite into a single trunk, which termi-
nates on the left side, in the thoracic duct ; on the right side, in the right lym-
phatic duct.
Lymphatics of the Uppee Extremity.
The Lymphatic Glands of the upper extremity (Fig. 347) may be subdivided
into two sets, superficial and deep.
The superficial lymphatic glands are few and of small size. There are occa-
sionally two or three in front of the elbow, and one or two above the internal
condyle of the humerus, near the basilic vein.
Fig. 347. — The Superficial Lymphatics aud Glands of the Upper Extremity.
jLxiliizrj^ Glands.
The deep lymphatic glands are also few in number. In the forearm a few
small ones are occasionally found in the course of the radial and ulnar vessels;
and in the arm, there is a chain of small glands along the inner side of the bra-
chial artery.
38
594 LYMPHATICS.
The axillary glands are of large size, and usually ten or twelve in number.
A chain of these glands surrounds the axillary vessels imbedded in a quantity
of loose areolar tissue; they receive the lymphatic vessels from the arm; others
are dispersed in the areolar tissue of the axilla : the remainder are arranged in
two series, a small chain running along the lower border of the Pectoralis major
as far as the mammary gland, receiving the lymphatics from the front of the
chest and mamma ; and others are placed along the lower margin of the poste-
rior wall of the axilla, which receive the lymphatics from the integument of
the back. Two or three subclavian lymphatic glands are placed immediately
beneath the clavicle ; it is through these that the axillary and deep cervical
glands communicate with each other. One is figured by Mascagni near the
umbilicus. In malignant diseases, tumors, or other affections implicating the
upper part of the back and shoulder, the front of the chest and mamma, the
upper part of the front and side of the abdomen, or the hand, forearm, and arm,
the axillary glands are liable to be found enlarged.
The sujierficial lymphatics of the upper extremity arise from the skin of the
hand, and run along the sides of the fingers chiefly on the dorsal surface of the
hand ; they then pass up the forearm, and subdivide into two sets, which take
the course of the subcutaneous veins. Those from the inner border of the hand
accompany the ulnar veins along the inner side of the forearm to the bend of
the elbow, where they join with some lymphatics from the outer side of the fore-
arm ; they then follow the course of the basilic vein, communicate with the glands
immediately above the elbow, and terminate in the axillary glands, joining with
the deep lymphatics. The superficial lymphatics from the outer and back part
of the hand accompany the radial veins to the bend of the elbow. They are less
numerous than the preceding. At the bend of the elbow, the greater number
join the basilic group; the rest ascend with the cephalic vein on the outer side
of the arm, some crossing the upper part of the Biceps obliquely, to terminate
in the axillary glands, whilst one or t^vo accompany the cephalic vein in the
cellular interval between the Pectoralis major and Deltoid, and enter the sub-
clavian lymphatic glands.
The deep lymphatics of the upper extremity accompany the deep bloodvessels.
In the forearm, they consist of three sets, corresponding with the radial, ulnar,
and interosseous arteries ; they pass through the glands occasionally found in
the course of those vessels, and communicate at intervals with the superficial
lymphatics. In their course upwards, some of them pass through the glands
which lie upon the brachial artery; they then enter the axillary and subclavian
glands, and at the root of the neck terminate, on the left side, in the thoracic
duct, and on the right side in the right lymphatic duct.
Lymphatics of the Lower Extremity.
The Lymphatic Olands of the lower extremity may be subdivided into two
sets, superficial and deep ; the former are confined to the inguinal region.
The superficial inguinal glands^ placed immediately beneath the integument,
are of large size, and vary from eight to ten in number. They are divisible into
two groups: an upper, disposed irregularly along Poupart's ligament, which
receive the lymphatic vessels from the integument of the scrotum, penis, parietcs
of the abdomen, perineal and gluteal regions ; and an inferior group, which
surround the saphenous opening in the fascia lata, a few being sometimes con-
tinued along the saphenous vein to a variable extent. The latter receive the
superficial lymphatic vessels from the lower extremity. These glands frequently
become enlarged in diseases implicating the parts from which their lymphatics
originate. Thus in malignant or syphilitic afiections of the prepuce and penis,
or of tlic labia majora in the female, in cancer scroti, in abscess in the perineum,
or in any other disease afiecting the inlogument and superficial structures in
those parts, or the sub-umbilical part oT the abdomen or gluteal region, the
OF THE LOWER EXTREMITY.
595
upper cTiain of glands is almost invaria-
bly enlarged, the lower chain being im-
plicated in diseases affecting the lower
limb.
The dee'p lymphatic glands are, the an-
terior tibial, popliteal, deep inguinal,
gluteal, and ischiatic.
The anterior tibial gland is not con-
stant in its existence. It is generally
found by the side of the anterior tibial
artery, upon the interosseous membrane
at the upper part of the leg. Occasion-
ally, two glands are found in this situa-
tion.
The deep popUteal glands^ four or five
in number, are of small size ; they sur-
round the popliteal vessels, imbedded in
the cellular tissue and fat of the popliteal
space.
The deep inguinal glands are placed
beneath the deep fascia around the femo-
ral artery and vein. They are of small
size, and communicate with the super-
ficial inguinal glands through the saphe-
nous opening.
The gluteal and ischiatic glands are
placed, the former above, the latter below
the Pyriformis muscle, resting on their
corresponding vessels as they pass
through the great sacro-sciatic foramen.
The Lymphatics of the lower extremity,
like the veins, may be divided into two
sets, superficial and deep.
The superficial lymphatics are placed
between the integument and superficial
fascia, and are divisible into two groups :
an internal group, which follow the
course of the internal saphenous vein ;
and aD external group, which accompany
the external saphenous. The internal
groups the larger, commences on the
inner side and dorsum of the foot ; they
pass, some in front, and some behind the
inner ankle, run up the leg with the in-
ternal saphenous vein, pass with it be-
hind the inner condyle of the femur, and
accompany it to the groin, where they
terminate in the group of inguinal glands
which surround the saphenous opening.
Some of the efferent vessels from these
glands pierce the cribriform fascia and
sheath of the femoral vessels, and termi-
nate in a lymphatic gland contained in
the femoral canal, thus establishing a
communication between the lymphatics
of the lower extremity and those of the
trunk ; others pierce the fascia lata, and
Fio:.
348. — The Superficial Lymphatics and
Glands of the Lower Extremity.
596 LYMPHATICS.
join the deep inguinal glands. The external gi'oup arise from the outer side of
the foot, ascend in front of the leg, and, just below the knee, cross the tibia from
without inwards, to join the lymphatics on the inner side of the thigh. Others
commence on the outer side of the foot, pass behind the outer malleolus, and
accompanj^ the external saphenous vein along the back of the leg, where they
enter the popliteal glands.
The dee^:) lymphatics of the lower extremity are few in member, and accompany
the deep bloodvessels. In the leg, they consist of three sets^ the anterior tibial,
peroneal, and posterior tibial, which accompany the corresponding bloodvessels,
two or three to each artery ; they ascend with the bloodvessels, and enter the
lymphatic glands in the popliteal space; the efferent vessels from these glands
accompany the femoral vein, and join the deep inguinal glands; from these, the
vessels pass beneath Poupart's ligament, and communicate with the chain of
glands surrounding the external iliac vessels.
The deep lymphatics of the gluteal and ischiatic regions follow the course of
the bloodvessels, and join the gluteal and ischiatic glands at the great sacro-
sciatic foramen.
Lymphatics of the Pelvis and Abdomen.
The deep lymphatic glands in the pelvis are, the external iHac, the internal
iliac, and the sacral. Those of the abdomen are the lumbar glands.
The external iliac gkmds form an uninterrupted chain round the external iliac
vessels, three being placed round the commencement of the vessels just behind
the crural arch. They communicate below witJi the femoral lymphatics, and
above with the lumbar glands.
The internal iliac glands surround the internal iliac vessels; the}^ receive the
lymphatics corresponding to the branches of the internal iliac artery, and com-
municate with the lumbar glands.
The sacral glands occupy the sides of the anterior surface of the sacrum, some
being situated in the meso- rectal fold. These and the internal iliac glands are
affected in malignant disease of the bladder, rectum, or uterus.
The lumbar glands are very numerous; they are situated on the front of the
lumbar vertebra, surrounding the common iliac vessels, the aorta and vena
cava; they receive the lymphatic vessels from the lower extremities and pelvis,
as well as from the testes and some of the abdominal viscera; the efferent
vessels from these glands unite into a few large trunks which, with the lacteals,
form the commencement of the thoracic duct. In some cases of malignant dis-
ease, these glands become enormously enlarged, completely surrounding the
aorta and vena cava, and occasionally greatly contracting the calibre of those
vessels. In all cases of malignant disease of the testis, and in malignant disease
of the lower limb, before any operation is attempted, careful examination of
the abdomen should be made, in order to ascertain if any enlargement exists:
and if any should be detected, all operative measures should be avoided, as
fruitless.
The lymphatics of lite pelvis and cdjdomen may be divided into two sets, super-
ficial and deep.
The superficial lym.phatics of the tcalls of the cd>domen and pelvis ioWowr the
course of the superficial bloodvessels. Those derived from the integument of
the lower part of the abdomen below the umbihcus, follow the course of the
superficial epigastric vessels, and converge to the superior group of the super-
ficial inguinal glands; the deep set accompany the deep epigastric vessels, and
communicate, with the external iliac glands. The superficial lymphatics from
the sides of the lumbar part of the abdominal wall wind round the crest of the
ilium, accompanying the superficial circumflex iliac vessels, to join the superior
group of the superficial inguinal glands; the greater number, however, run
OF THE PELVIS AND ABDOMEN.
597
backwards along with the ilio-lumbar and lumbar vessels, to join the lumbar
glands.
The superficial lymphatics of the gluteal region turn horizontally round the
outer side of the nates, and join the supei^ficial inguinal glands.
The superficial ly')nphatics of the scrottion and pjerinewin follow the course of
the external pudic vessels, and terminate in the superficial inguinal glands.
Fig. 34.9. — The Deep Lymphatic Vessels and Glands of the Abdomen and Pelvis.
jExtBrnal
IliciP Glands
Glands
''^ I r.^^'
The superficial lymphatics of the penis occupy the sides and dorsum of the
organ, the latter receiving the lymphatics from the skin covering the glans
penis; they all converge to the upper chain of the superficial inguinal glands.
The deep lymphatic vessels of the penis follow the course of the internal pudic
vessels, and join the internal iliac glands.
598 LYMPHATICS.
In tlie female, tlae lymphatic vessels of tlie mucous membrane of tlie labia,
nymphee, and clitoris, terminate in tbe upper chain of the inguinal glands.
The clee]D lymphatics of the pelvis and abdomen take the course of the principal
bloodvessels. Those of the parietes of the pelvis, which accompany the gluteal,
ischiatic, and obturator vessels, follow the course of the internal iliac artery, and
ultimately join the lumbar lymphatics.
The efferent vessels from the inguinal glands enter the pelvis beneath Pou-
part's ligament, where they lie in close relation with the femoral vein ; they
then pass through the chain of glands surrounding the external iliac vessels, and
finally terminate in the lumbar glands. They receive the deep epigastric,
circumflex iliac, and ilio-lumbar lymphatics.
The lympthatics of the bladder arise from the entire surface of the organ ; the
greater number run beneath the peritoneum on its posterior surface, and, after
passing through the lymphatic glands in that situation, join with the lymphatics
from the prostate and vesiculee seminales, and enter the internal iliac glands.
The lymphatics of the rectum, are of large size ; after passing through some
small glands that lie upon its outer wall and in the meso-rectum, they pass to
the sacral or lumbar glands.
The lympjhatics of the uterus consist of two sets, siiperficial and deep : the
former being placed beneath the peritoneum, the latter in the substance of the
organ. The lymphatics of the cervix uteri, together with those from the vagina,
enter the internal iliac and sacral glands ; those from the body and fundus of the
uterus pass outwards in the broad ligaments, and, being joined by the lympha-
tics from the ovaries, broad ligaments, and Fallopian tubes, ascend with the
ovarian vessels to open into the lumbar glands. In the unimpregnated uterus,
they are small ; but during gestation, they become very greatly enlarged.
The lymphatics of the testicle consist of two sets, superficial and deep ; the
former commence on the surface of the tunica vaginalis, the latter in the epidi-
dymis and body of the testis. They form several large trunks, which ascend
with the spermatic cord, and accompanying the spermatic vessels into the abdo-
men, open into the lumbar glands ; hence the enlargement of these glands in
malignant disease of the testis.
The lymphatics of the hidney arise on the surface, and also in the interior of
the organ ; they join at the hilum, and, after receiving the lymphatic vessels
from the ureter and suprarenal capsules, open into the lumbar glands.
The lymphatics of the liver are divisible into two sets, superficial and deep.
The former arise in the sub-peritoneal areolar tissue over the entire surface of
the organ. Those on the convex surface may be divided into four groups : 1.
Those which pass from behind forwards, consisting of three or four branches,
which ascend in the longitudinal ligament, and unite to form a single trunk,
which passes up between the fibres of the Diaphragm, behind the ensiform
cartilage to enter the anterior mediastinal glands, and finally ascends to the root
of the neck, to terminate in the right lymphatic duct. 2. Another group, which
also incline from behind forwards, are reflected over the anterior margin of the
liver to its under surface, and from thence pass along the longitudinal fissure to
the glands in the gastro-hepatic omentum. 3. A third group incline outwards
to the right lateral ligament, and uniting into one or two large trunks, pierce
the Diaphragm, and run along its upper surface to enter the anterior mediastinal
glands ; or, instead of entering the thorax, turn inwards across the cms of the
Diaphragm, and open into the commencement of the thoracic duct. 4. The
fourth group inc^lino outwards from the surface of the left lobe of the liver to
the left lateral ligament, pierce tlic Diaphragm, and passing forwards, terminate
in the glands in tlie anterior mediastinum.
The snj)erfici((l lym/jJudics on the under surface of the liver are divided into
three sets: 1. Those cm tlie right side of the gall-bladder enter the lumbar
glands. 2. Those surrounding the gall blfukh'r form a remarkable plexus: they
accompany the hepatic vessels, and open iiit(j ihe glands in the gastro-hepatic
OF THE INTESTINES. 599
omentum. 8. Those on tlie left of the gall-bladder pass to tlie oesophageal
glands, and to the glands which are situated along the lesser curvature of the
stomach.
The deep lymphatics accompany the branches of the portal vein and the
hepatic artery and duct through the substance of the liver ; passing out at the
transverse fissure, they enter the lymphatic glands along the lesser curvature
of the stomach and behind the pancreas, or join with one of the lacteal vessels
previous to its termination in the thoracic duct.
The lymphatic cjlands of the stomach are of small size ; they are placed along
the lesser and greater curvatures, some within the gastro- splenic omentum,
whilst others surround the cardiac and pyloric orifices.
The lymphatics of the stomach consist of two sets, superficial and deep ; the
former originating in the subserous, and the latter in the submucous coat. They
follow the course of the bloodvessels, and may, consequently, be arranged into
three groups. The first group accompany the coronary vessels along the lesser
curvature, receiving branches from both surfaces of the organ, and pass to the
glands around the pylorus. The second group pass from the great end of the
stomach, accompany the vasa brevia, and enter the splenic lymphatic glands.
The third group run along tlie greater curvature with the right gastro-epiploic
vessels, and terminate at the root of the mesentery in one of the principal lacteal
vessels.
The lyrnphatic glands of the spleen occupy the hilum. Its lymphatic vessels
consist of two sets, superficial and deep; the former are placed beneath its
peritoneal covering, the latter in the substance of the organ : they accompany
the bloodvessels, passing through a series of small glands, and after receiving
the lymphatics from the pancreas, ultimately pass into the thoracic duct.
The Lymphatic System of the Ixtestines,
The lymphatic glands of the sm.all intestine are placed between the layers of
the mesentery, occupying the meshes formed by the superior mesenteric vessels,
and hence called mesenteric glands. They vary in number from a hundred to a
hundred and fifty : and in size, from that of a pea to that of a small almond.
These glands are most numerous, and largest, above near the duodenum, and
below opposite the termination of the ileum in the colon. This latter group
becomes enlarged and infiltrated with deposit in cases of fever accompanied with
ulceration of the intestines.
The lymphatic glands of the large intestine are much less numerous than the
mesenteric glands ; they are situated along the vascular arches formed by the
arteries previous to their distribution, and even sometimes upon the intestine
itself. They are fewest in number along the transverse colon, where they form
an uninterrupted chain with the mesenteric glands.
The lymphatics of the small intestine are called lacteals^ from the milk-white
fluid they usually contain : they consist of two sets, superficial and deep : the
former lie beneath the peritoneal coat, taking a longitudinal course along the
outer side of the intestine; the latter occupy the submucous tissue, and course
transversely round the intestine, accompanied by the branches of the mesenteric
vessels: they pass between the layers of the mesentery, enter the mesenteric
glands, and finally unite to form two or three large trunks, which terminate in
the thoracic duct.
The lymphatics of the large intestine consist of two sets : those of the csecum,
ascending and transverse colon, which, after passing through their proper glands,
enter the mesenteric glands; and those of the descending colon and rectum,
which pass to the lumbar glands.
GOO LYMPHATICS.
The Lymphatics of the Thoeax.
The deep lymphatic glands of the thorax are the intercostal, internal mammary,
anterior mediastinal, and posterior mediastinal.
The intercostal glands are small, irregular in number, and situated on each
side of the spine, near the costo-vertebral articulations, some being placed
between the two planes of intercostal muscles.
The internal mammary glands are placed at the anterior extremity of each
intercostal space, by the side of the internal mammary vessels.
The anterior mediastinal glands are placed in the loose areolar tissue of the
anterior mediastinum, some lying upon the Diaphragm in front of the pericar-
dium, and others round the great vessels at the base of the heart.
^\i(d posterior mediastinal glands are situated in the areolar tissue in the poste-
rior mediastinum, forming a continuous chain by the side of the aorta and
oesophagus; they communicate on each side with the intercostal, below with the
lumbar glands, and above with the deep cervical.
The superficial lymphatics of the front of the thorax run across the great Pecto-
ral muscle, and those on the back part of this cavity lie upon the Trapezius and
Latissimus dorsi ; they all converge to the axillary glands. The lymphatics
from the mamma run along the lower border of the Pectoralis major, through
a chain of small lymphatic glands, and communicate with the axillary glands.
The deep lymphatics of the thorax are the intercostal, internal mammary, and
diaphragmatic.
The intercostal lymphatics follow the course of the intercostal vessels, receiving
lymphatics from the intercostal muscles and pleura ; they pass backwards to
the spine^ and unite with lymphatics from the back part of the thorax and
spinal canal. After traversiing the intercostal glands, they incline down the
spine, and terminate in the thoracic duct.
The internal mammary lymphatics follow the course of the internal mammar}^
vessels; they commence in the muscles of the abdomen above the umbilicus
communicating with the epigastric lymphatics, ascend between the fibres of the
Diaphragm at its attachment to the ensiform appendix, and in their course
behind the costal cartilages are joined by the intercostal lymphatics, termi-
nating on the right side in the right lymphatic duct, on the left side in the
thoracic duct.
The lymphatics of the Diaphragm follow the course of their corresponding-
vessels, and terminate, some in front, in the anterior mediastinal and internal
mammary glands, some behind in the intercostal and hepatic lymphatics.
The bronchial glands are situated round the bifurcation of the trachea and
roots of the lungs. They are ten or twelve in number, the largest being placed
opposite the bifurcation of the trachea, the smallest round the bronchi and their
primary divisions for some little distance within the substance of the lungs.
In infancy, they present the same appearance as lymphatic glands in other situa-
tions, in the adult they assume a brownish tinge, and in old age a deep black
color. Occasionally, they become sufiiciently enlarged to compress and narrow
the canal of the bronchi ; and they are often the scat of tubercle or deposits of
phosphate of lime.
The lympliMtics of the lung consist of two sets, superficial and deep : the
former are placed beneath the pleura, forming a minute plexus, which covers the
outer surface of the lung ; the latter accompany the bloodvessels, and run along
the bronchi: they both terminate at the root of the lungs in the bronchial
glands. The efferent vessels from these glands, two or three in number, ascend
upon the tracihca to the root of the neck, traverse the tracheal and esophageal
glands, and terminate on the left side in the thoracic duct, and on the right side
in the right lymphatic duct.
The cardiac lymphatics consist of two sets, superficial and deep ; the former
arise in the subserous areolar tissue of the surface, and the latter beneath the
OF THE THORAX. 601
internal lining membrane of tlie heart. They follow the course of the coro-
nary vessels ; those of the right side unite into a trunk at the root of the aorta,
which, ascending across the arch of that vessel, passes backwards to the trachea,
upon which it ascends, to terminate. at the root of the neck in the right lym-
phatic duct. Those of the left side unite into a single vessel at the base of the
heart, which, passing along the pulmonary artery, and traversing some glands
at the root of the aorta, ascends on the trachea to terminate in the thoracic
duct.
The thymic lymjphatics arise from the spinal surface of the thymus gland, and
terminate on each side in the internal jugular veins.
The thyroid lymphatics arise from either lateral lobe of this organ ; they con-
verge to form a short trunk, which terminates on the right side in the right
lymphatic duct, on the left side in the thoracic duct.
The lymi^hatics of the oesophagus form a plexus round that tube, traverse the
glands in the posterior mediastinum, and, after communicating with the pulmo-
nary lymphatic vessels near the roots of the lungs, terminate in the thoracic
duct.
Nervous System.
The Nervous System is composed: 1. of a series of connected central organs,
called, collectively, the cerebrospinal centre or axis ; 2. of the yanglia ; and 3. of
the nerves.
The Cerebro-spinal Centre consists of two parts, the spinal cord and the ence-
phalon : the latter may be subdivided into the cerebrum, the cerebellum, the
pons Varolii, and the medulla oblongata.
The SpmAL Cord and its Membranes.
Dissection. To dissect the cord and its membranes, it will be necessary to lay open the whole
length of the spinal canal. For this purpose, the muscles must be separated from the vertebral
grooves, so as to expose the spinous processes and laminaj of the vertebras ; and the latter must be
sawn through on each side, close to the roots of the transverse processes, from the third or fourth
cervical vertebra, above, to the sacrum below. The vertebral arches having been displaced, by
means of a chisel, and the separate fragments removed, the dura maler will be exposed, covered
by a plexus of veins and a quantity of loose areolar tissue, often infiltrated with serous fluid. The
arches of the upper vertebrae are best divided by means of a strong pair of cutting bone-forceps.
Membranes of the Cord.
The Membranes which envelop the spinal cord are three in number. The
most external is the dura mater, a strong fibrous membrane, which forms a loose
sheath around the cord. The most internal is the pia mater, a cellulo-vascular
membrane, which closely invests the entire surface of the cord. Between the
two is the arachnoid membrane, an intermediate serous sac, which envelops
the cord, and is then reflected on the inner surface of the dura mater.
The Dura Mater of the cord, continuous with that which invests the brain,
is a loose sheath which surrounds the cord, and is separated from the bony
walls of the spinal canal by a quantity of loose areolar adipose tissue, and a
plexus of veins. It is attached to the circumference of the foramen magnum,
and to the posterior common ligament, throughout the whole length of the spinal
canal, by fibrous tissue ; and extends, below, as far as the top of the sacrum ; but
beyond this point, it is impervious, being continued, in the form of a slender cord,
to the back of the coccj^x, where it blends with the periosteum. This sheath is
much larger than is necessary for its contents, and its size is greater in the cer-
vical and lumbar regions than in the dorsal. Its inner surface is smooth, covered
by a layer of polygonal cells ; and on each side may be seen the double openings
which transmit the two roots of the corresponding spinal nerve, the fibrous layer
of the dura mater being continued in the form of a tubular prolongation on them
as they issue from these apertures. These prolongations of the dura mater are
short in the upper part of the spine, but become gradually longer below, forming
a number of tabes of fibrous membrane, which inclose the sacral nerves, and
are contained in the spinal canal.
The chief peculiarities of the dura mater of the cord, as compared with that
investing the brain, arc the followino;:
The dura mater of the cord is not adherent to ilic bones of the spinal canal,
which have an independent periosteum.
It does not send partitions into the fissures of the cord, as in the brain.
Its fibrous lamimc do not separate, to fonn venous sinuses, as in the brain.
Structv,re. The dura mater consists of \vlii1e fibrous ti^ssue, arranged in bands
( 602 )
MEMBRANES OF THE SPINAL CORD.
603
Fi;
•. 350.- The Spinal (Jord
aud its JVlembianc's.
-wHcb. intersect one anotlier. It is sparingly supplied with vessels; and no
nerves liave as yet been traced into it.
The Arachnoid is exposed by slitting up the dura mater, and reflecting that
membrane to either side (Fig. 350).. It is a thin, delicate serous membrane,
which invests the outer surface of the cord, and is
then reflected upon the inner surface of the dura
mater, to which it is intimately adherent. Above,
it is continuous with the cerebral arachnoid ; below,
it is reflected on the various nerves, so that its parie •
tal and visceral layers become continuous with each
other. The visceral layer is the portion which sur-
rounds the cord, and that which lines the inner surface
of the dura mater is called the parietal layer -^ the in-
terval between the two is called the cavity of the
arachnoid. The visceral layer forms a loose sheath
around the cord, so as to leave a considerable interval
between the two, which is called the suh-arachnoidean
space. This space is largest at the lower part of the
spinal canal, aud incloses the mass of nerves which form
the Cauda equina. It contains an abundant serous
secretion, the cerebro- spinal fluid, and usually commu-
nicates with the general ventricular cavity of the brain,
by means of an opening in the fibrous layer of the in-
ferior boundary of the fourth ventricle. This secre-
tion is sufficient in amount to expand the arachnoid
membrane, so as to completely fill up the whole of the
space included in the dura mater. The sub-arach-
noidean space is crossed, at the back part of the cord,
by numerous fibrous bands, which stretch from the
arachnoid to the pia mater, especially in the cervical region, and is partially sub-
divided by a longitudinal membranous partition, which serves to connect the
arachnoid with the pia mater, opposite the posterior median fissure. This parti-
tion is incomplete, and cribriform in structure, consisting of bundles of white
fibrous tissue, interlacing with each other.
The visceral layer of the arachnoid sur-
rounds the spinal nerves where they arise
from the cord, and incloses them in a tubu-
lar sheath as far as their point of exit from
the dura mater, where it becomes continuous
with the parietal layer.
The arachnoid is destitute of vessels. No
nerves have as yet been traced into this
membrane.
The Pia Mater of the cord is exposed on
the removal of the arachnoid (Fig. 350). It
is less vascular in structure than the pia mater of the brain, with which it is
continaous, being thicker, more dense in structure, and composed of fibrous
tissue, arranged in longitudinal bundles. It covers the entire surface of the cord,
to which it is very intimately adherent, forming its neurilemma, and sends a
process downwards into its anterior fissure, and another, extremely delicate, into
the posterior fissure. It also forms a sheath for each of the filaments of the
spinal nerves, and invests the nerves themselves. A longitudinal fibrous band
extends along the middle line on its anterior surface, called by Haller the linea
Fig. 351. — Transverse Section of the
Spinal Cord and its Membranes.
' Kblliker denies that the inner surFace of the dura mater is covered by an outer layer of the
arachnoid, and states that nothing is found here except an epithelial layer, no trace of a special
membrane existin"-.
604 NEEVOUS SYSTEM.
splendens; and a somewliat similar band, the ligamentum denticulatnm, is
situated on eacli side. At the point where the cord terminates, the pia mater
becomes contracted, and is continued down as a long, slender filament [filum
terminale)^ which descends through the centre of the mass of nerves forming the
Cauda equina, and is blended with the impervious sheath of dura mater, on a
level with the top of the sacral canal. It assists in maintaining the cord in its
position during the movements of the trunk, and is, from this circumstance,
called the central ligament of the spinal cord. It contains a little gray nervous
substance, which may be traced for some distance into its up]3er part, and is
accompanied by a small artery and vein.
Structure. The pia mater of the cord, though less vascular than that which
invests the brain, contains a network of delicate vessels in its substance. It is
also supplied with nerves, which are derived from the sympathetic, and from
the posterior roots of the spinal nerves. At the upper part of the cord, the pia
mater presents a grayish, mottled tint, which is owing to yellowish or brown
pigment cells being scattered within its tissue.
The Liyamentum Denticulatum or Dentatum (Fig. 850) is a narrow fibrous
band, situated on each side of the spinal cord, throughout its entire length, and
separating the anterior from the posterior roots of the spinal nerves, having
received its name from the serrated appearance which it presents. Its inner
border is continuous with the pia mater, at the side of the cord. Its outer
border presents a series of triangular, dentated serrations, the points of which
are fixed, at intervals, to the dura mater, serving to unite together the two
layers of the arachnoid membrane. These serrations are abont twenty in
number, on each side, the first being attached to the dura mater, opposite the
margin of the foramen magnum, between the vertebral artery and the hypo-
glossal nerve ; and the last near the lower end of the cord. Its use is to support
the cord in the fluid by which it is surrounded.
The Spinal Cord.
The Spinal Cord [medulla spinalis) is the cylindrical elongated part of the
cerebro-spinal axis, which is contained in the vertebral canal. Its length is
usually about sixteen or seventeen inches, and its weight, when divested of its
membranes and nerves, about one ounce and a half, its proportion to the
encephalon being about 1 to 33. It does not nearly fill the canal in which it is
contained, its investing membranes being separated from the surrounding walls
by areolar tissue and a plexus of veins. It occupies, in the adult, the upper
two-thirds of the vertebral canal, extending from the upper border of the atlas
to the lower border of the body of the first lumbar vertebra, where it termi-
nates in a slender filament of gray substance, which is continued for some dis-
tance into i\\Q filum terminale. In the foetus, before the third month, it extends
to the bottom of the sacral canal ; but, after this period, it gradually recedes
from below, as the growth of the bones composing the canal is more rapid in
proportion than that of the cord ; so that, in the child at birth, the cord extends
as far as the third lumbar vertebra. Its position varies also according to the
degree of curvature of the spinal column, being raised somewhat in flexion of -
the spine. On examining its surface, it presents a difference in its diameter in
different part«, being marked by two enlargements, an up])cr or cervical, and a
lower or lumbar. The cervical enlargement, which is the larger, extends from
the third cervical to the first dorsal vertebra : its greatest diameter is in the
transverse direction, and it corresponds with the origin of the nerves which
supply the upper extremities. The lower, or lumbar enlargement, is situated
opposite the last dorsal vertebra, its greatest diameter being from before back-
wards. It corresponds with the origin of the nerves which su]-)[)ly the lower
extremities. In form, the s])inal cord is a flattened cylinder. It presents, on its
anterior surface, along the middle line, a longitudinal fissure, the anterior median
SPINAL CORD.
605
Fi«-. 352.— Spinal Cord. Side
View. Plan of the Fissures
and Columns.
fissure ; and, on its posterior surface, another fissure, which also extends along
the entire length of the cord, the posterior median fissure. These fissures serve
to divide the cord into two symmetrical halves, which are united in the middle
line, throughout their entire length, by a transverse band of nervous substance,
the commissure.
The Anterior median fissure is wider, but of less depth than the posterior,
extending into the cord for about one-third of its thickness, and is deepest at
the lower part of the cord. It contains a prolongation from the pia mater ; and
its floor is formed by the anterior white commissure, which is perforated by
numerous bloodvessels, passing to the centre of the cord.
The Posterior median fissure is much more delicate than the anterior, and
most distinct at the upper and lower parts of the cord. It extends into the cord
to about one-half of its depth. It contains a very
slender process of the pia mater, and numerous blood-
vessels, and its floor is formed by a thin layer of
white substance, the posterior white commissure.
Some anatomists state that the bottom of this fissure
corresponds to the gray matter, except in the cervi-
cal region, and at a point corresponding to the en-
largement in the lumbar region.^
Lateral Fissures. On either side of the anterior
median fissure, a linear series of foramina may be
observed, indicating the points where the anterior
roots of the spinal nerves emerge from the cord.
This is called, by some anatomists, the antero-lateral
fissure of the cord, although no actual fissure exists
in this situation. And on either side of the posterior
median fissure, along; the line of attachment of the
posterior roots of the nerves, a delicate fissure may be seen, leading down to
the gray matter which approaches the surface in this situation ; this is called
the postero-lateral fissure of the spinal cord. On the posterior surface of the
spinal cord, on either side of the posterior median fissure, is a slight longitudinal
furrow, marking off two slender tracts, the posterior median columns. These
are most distinct in the cervical region, but are stated by Foville to exist through-
out the whole lens-th of the cord.
Columns of the Cord. The fissures divide each half of the spinal cord into four
columns, an anterior column, a lateral column, a posterior column, and a poste-
rior median column.
The anterior column includes all the portion of the cord between the anterior
median fissure and the antero-lateral fissure, from which the anterior roots of
the nerves arise. It is continuous with the anterior pyramid of the medulla
oblongata.
The lateral column., the largest segment of the cord, includes all the portion
between the antero- and postero-lateral fissures. It is continuous with the
lateral column of the medulla. By some anatomists, the anterior and lateral
columns are included together, under the name of the antero-lateral column,
which forms rather more than two-thirds of the entire circumference of the cord.
T!:}iQ posterior column is situated between the posterior median and postero-
lateral fissures. It is continuous with the restiform body of the medulla.
The posterior median column is that narrow segment of the cord which is seen
on each side of the posterior median fissure, usually included with the preceding,
as the posterior column.
Structure of the Cord. If a transverse section of the spinal cord be made, it
' This was the teaching of Vicq d'Azyr, who is followed by Sappey and most of the best modern
anatomists. On the other hand, Meckel strongly affirms the existence of a distinct posterior white
commissure.
606
NERVOUS SYSTEM.
Fig. 353. — Transverse Sections
of the Cord.
will be seen to consist of white and gray nervous substance. Tlie white matter
is situated externally, and constitutes the greater part. The gray substance
occupies the centre, and is so arranged as to present on the surface of the
section two crescentic masses placed one in each lateral half of the cord, united
together by a transverse band of gray matter, the gray commissure. Each
crescentic mass has an anterior and posterior horn. The posterior horn is long
and narrow, and approaches the surface of the posterolateral fissure, near which
it presents a slight enlargement. The anterior horn is short and thick, and
does not quite reach the surface, but extends towards the point of attachment
of the anterior roots of the nerves. Its margin presents a dentate or stellate
appearance. Owing to the projections towards the surface of the anterior and
posterior horns of the gray matter, each half ot the cord is divided, more or less
completely, into three columns, anterior, middle, and posterior; the anterior
and middle being joined to form the antero-lateral column, as the anterior horn
does not quite reach the surface.
The gray commissure, which connects the two crescentic masses of gray
matter, is separated from the bottom of the anterior median fissure by the
anterior white commissure; and from the bottom of
the posterior fissure by the posterior white commis-
sure. The gray commissure consists of a transverse
band of gray matter and of white fibres, derived
from the opposite half of the cord and the posterior
roots of the nerves. The anterior commissure is
formed of fibres, partly from the anterior column,
and partly from the fibrils of the anterior roots of
the spinal nerves, which decussate as they pass
across from one to the other side.
The mode of arrangement of the gray matter, and
its amount in proportion to the white, vary in dif-
ferent parts of the cord. Thus, the posterior horns
are long and narrow, in the cervical region ; short
and narrower, in the dorsal ; short, but wider, in the
lumbar region. In the cervical region, the crescentic
portions are small, and the white matter more abun-
dant than in any other region of the cord. In the
dorsal region, the gray matter is least developed, the
white matter being also small in quantity. In the lumbar region, the gray
matter is more abundant than in any other region of the cord. Towards the
lower end of the cord, the white matter gradually ceases. The crescentic
portions of the gray matter soon blend into a siugle mass, which forms the
only constituent of the extreme point of the cord.
The minute anatomy of the cord was described in the Introduction.
0^2'oslie IdLiidle of Cervical Tcnn
0£jie.?ite Middle a/" Dorsal rtqit.
Opposite ZuTnbar Tc(/io7v
The Braijst and its Membranes.
Dissectinn. To cxjimine llie brain with its mcniljranos, the sknll-cnp mnst be removed. In
order to effect this, saw through the e.xternal table, the section coiiinienciiig, in front, about an
inch above the marg'in of the orbit, and exteiidiiifr. behind, to a level witli the occipital ])ro1nbe-
rance. 'I'hen break the internal table with the cliisel and lianimer, 1o avoid injnrinji,'' the investing:
membranes or brain ; loosen, and forcibly detach the sknll. wlien the dura mater will be exposed,
n'he adhesion between the bone and the dura mater is very intimate, and much more so in the
young subject than in the adult.
Tlic Membranes of the Brain are, the dura mater, arachnoid membrane, and
pi a mater.
Dura Mater,
The Dura Mater is a lliick find dense inolnstic fibrons mombrnno, Avliich lines
the interior of tlic skull. Its outer surface is rouLdi and lHu-illalcd, and adheres
DURA MATER. 607
closely to tlie iuner surface of tlie bones, forming tlieir internal periosteum, this
adliesion being more intimate opposite the sutures and at the base of the skull ;
at the margin of the foramen magnum, it becomes continuous with the dura
mater lining the spinal canal. Its inner surface is smooth and epitheliated,
being lined by the parietal layer of the arachnoid. The dura mater is, therefore,
a fibro-serous membrane, composed of an external fibrous lamella and an internal
serous layer. It sends numerous processes inwards, into the cavity of the skull,
for the support and protection of the different parts of the brain; and is pro-
longed to the outer surface of the skull, through the various foramina which
exist at the base, and thus becomes continuous with the pericranium; its fibrous
layer forms sheaths for the nerves which pass through these apertures. At
the base of the skull, it sends a fibrous prolongation into the foramen cjecum ;
it lines the olfactory groove, and sends a series of tubular prolongations round
the filaments of the olfactory nerves as they pass through the cribriform plate ;
a prolongation is also continued through the sphenoidal fissure into the orbit,
and another is continued into the same cavity through the optic foramen, forming
a sheath for the optic nerve, which is continued as far as the eyeball. In certain
situations in the skull already mentioned, the fibrous layers of this membrane
separate, to form sinuses for the passage of venous blood. Upon the upper
surface of the dura mater, in the situation of the longitudinal sinus, may be
seen numerous small whitish bodies, the glandulge Pacchioni.
Structure. The dura mater consists of white fibrous and elastic tissues,
arranged in flattened laminae, which intersect one another in every direction.
Its arteries are very numerous, but are chiefly distributed to the bones. Those
found in the anterior fossa are the anterior meningeal branches of the anterior
and posterior ethmoidal, and internal carotid. In the middle fossa are the
middle and small meningeal, branches of the internal maxillary, and a third
branch from the ascending pharyngeal, which enters the skull through the
foramen lacerum basis cranii. In the posterior fossa, are the meningeal branch
of the occipital, which enters the skull through the jugular foramen; the pos-
terior meningeal, from the vertebral; and occasionally meningeal branches from
the ascending pharyngeal, which enter the skull, one at the jugular foramen,
the other at the anterior condyloid foramen.
The veins^ which return the blood from the dura mater, and partly from the
bones, anastomose with the diploic veins. These vessels terminate in the
various sinuses, with the exception of two which accompany the middle menin-
geal artery, and pass out of the skull at the foramen spinosum.
The nerves of the dura mater are, the recurrent branch of the fourth, and
filaments from the Casserian ganglion, from the ophthalmic nerve, and from
the sympathetic.
The so-called glandulse Pacchioni are numerous small whitish granulations,
usually collected into clusters of variable size, which are found in the following
situations: 1. Upon the outer surface of the dura mater, in the vicinity of the
superior longitudinal sinus, being received into little depressions on the inner
surface of the calvarium. 2. On the inner surface of the dura mater. 3. In
the superior longitudinal sinus. 4. On the pia mater, near the margin of the
hemispheres.
These bodies are not glandular in structure, but consist of a fibro-cellular
matrix originally developed from the pia mater; by their growth they produce
absorption or separation of the fibres of the dura mater; in a similar manner
they make their way into the superior longitudinal sinus, where they are
covered by the lining membrane. The cerebral layer of the arachnoid in the
situation of these growths is usually thickened and opaque, and adherent to the
parietal portion.
These bodies are not found in infancy, and very rarely until the third year.
They are usually found after the seventh year; and from this period they in-
crease in number as age advances. Occasionally they are wanting.
608 NERVOUS SYSTEM.
Processes of the Dura Mater. Tlie processes of tlie dura mater, sent inwards
into the cavity of tlie skull, are three in number, the falx cerebri, the tentorium
cerebelli, and the falx cerebelli.
The/aZx cerebri^ so named from its sickle-like form, is a strong arched pro-
cess of the dura mater, which descends vertically in the longitudinal fissure
between the two hemispheres of the brain. It is narrow in front, where it is
attached to the crista galli process of the ethmoid bone ; and broad behind,
where it is connected with the upper surface of the tentorium. Its upper mar-
gin is convex, and attached to the inner surface of the skull as far back as the
internal occipital protuberance. In this situation it is broad, and contains the
superior longitudinal sinus. Its lower margin is free, concave, and presents a
sharp curved edge, which contains the inferior longitudinal sinus.
The tentorium cerehelU is an arched lamina of dura mater, elevated in the
middle, and inclining downwards towards the circumference. It covers the
u]323er surface of the cerebellum, supporting the posterior lobes of the brain, and
preventing their pressure upon it. It is attached, behind, by its convex border,
to the transverse ridges upon the inner surface of the occipital bone, and there
incloses the lateral sinuses ; in front, to the superior margin of the petrous
portion of the temporal bone, inclosing the superior petrosal sinuses, and from
the apex of this bone, on each side, is continued to the anterior and posterior
clinoid processes. Along the middle line of its upper surface, the posterior
border of the falx cerebri is attached, the straight sinus being placed on their
point of junction. Its anterior border is free and concave, and presents a large
oval opening for the transmission of the crura cerebri.
The/a/;c cerebelli is a small triangular process of dura mater, received into
the indentation between the two lateral lobes of the cerebellum behind. Its
base is attached, above, to the under and back part of the tentorium ; its poste-
rior margin, to the lower division of the vertical crest on the under surface of
the occipital bone. As it descends, it sometimes divides into two smaller folds,
which are lost on the sides of the foramen magnum.
Aeachnoid Membrane.
The Arachnoid (dpaarvj;, fiSo?, lihe a spider^s web), so named from its extreme
thinness, is the serous membrane which envelops the brain, and is then reflected
on the inner surface of the dura mater. Like other serous membranes, it is a
shut sac, and consists of a parietal and a visceral layer.
The 2^arietal layer covers the inner surface of the dura mater,^ and gives that
membrane its smooth and polished surface ; it is also reflected over those sur-
faces which separate the hemispheres of the brain and cerebellum.
The visceral layer invests the brain more loosely, being separated from direct
contact with the cerebral substance by the pia mater, and a quantity of loose
areolar tissue, the subarachnoidean. On the upper surface of the cerebrum, the
arachnoid is thin and transparent, and may be easily demonstrated by injecting
a stream of air beneath it by means of a blowpipe ; it passes over the convolu-
tions without dipping down into the sulci between them. At the base of the
brain the arachnoid is thicker, and slightly opaque towards the central part ;
it covers the anterior lobes, and is extended across between the two middle
lobes, so as to leave a considerable interval between it and the brain, the ante-
rior subarachnoidean space; it is closely adherent to the pons and under surface
of the cerebellum; but between the hemispheres of the cerebellum and the
medulla oblongata another considerable interval is left between it and the
brain, called the posterior suharacliri.oid.ean space. These tAVO spaces conimnnicalc
' Kiillikcr dfriioR tliia; and sfatos. that Ibo innor surface of tlio dura mater is covered willi
pavr-ment ei-iillielium, but lias no otlior investment whicli can be regarded as a parietal layer of
tlie arachnoid.
PIA MATER THE BRAIN. 609
together across the crura cerebri. The arachnoid membrane surrounds the
nerves which arise from the brain, and incloses them in loose sheaths as far as
their point of exit from the skull, where it becomes continuous with the parietal
layer.
The suharachnoid space is the interval between the arachnoid and pia mater :
this space is narrow on the surface of the hemispheres ; but at the base of the
brain a wide interval is left between the two middle lobes, and behind, between
the hemispheres of the cerebellum and the medulla oblongata. This space is
the seat of an abundant serous secretion, the cerebro-spinal fluid, which fills up
the interval between the arachnoid and pia mater. The subarachnoid space
usually communicates with the general ventricular cavity of the brain by means
of an opening in the inferior boundary of the fourth ventricle.
The sac of the arachnoid also contains serous fluid; this is, however, small in
quantity compared with the cerebro-spinal fluid.
Structure. The arachnoid consists of bundles of white fibrous and elastic
tissues intimately blended together. Its outer surface is covered with a layer
of scaly epithelium. It is destitute of vessels, and the existence of nerves in it
has not been satisfactorily demonstrated.
The cerehro-siyinal fluid fills up the subarachnoid space, kee]3ing the opposed
surfaces of the arachnoid membrane in contact. It is a clear, limpid fluid, hav-
ing a saltish taste, and a slightly alkaline reaction. According to Lassaigne, it
consists of 98.5 parts of water, the remaining 1.5 per cent, being solid matters,
animal and saline. It varies in quantity, being most abundant in old persons,
and is quickly reproduced. Its chief use is probably to aftbrd mechanical pro-
tection to the nervous centres, and to prevent the efiects of concussions commu-
nicated from without.
Pia Matee.
The Pia Mater is a vascular membrane, and derives its blood from the internal
carotid and vertebral arteries. It consists of a minute plexus of bloodvessels,
held together by an extremely fine areolar tissue. It invests the entire surface
of the brain, dipping down between the convolutions and laminae, and is pro-
longed into the interior, forming the velum interpositum and choroid plexuses
of the fourth ventricle. Upon the surfaces of the hemispheres, where it covers
the gray matter of the convolutions, it is very vascular, and gives off' from its
inner surface a multitude of minute vessels, which extend perpendicularly for
some distance into the cerebral substance. At the base of the brain, in the
situation of the substantia perforata and locus perforatus, a number of long
straight vessels are given off, which pass through the white matter to reach the
gray substance in the interior. On the cerebellum the membrane is more deli-
cate, and the vessels from its inner surface are shorter. Upon the crura cerebri
and pons Varolii its characters are altogether changed; it here presents a dense
fibrous structure, marked only bj^ slight traces of vascularity.
According to Fohmann and Arnold, this 'membrane contains numerous lym-
phatic vessels. Its nerves are derived from the sympathetic, and also from the
third, sixth, seventh, eighth, and spinal accessory. They accompany the branches
of the arteries.
The Brain.
The Brain (encephalon) is that portion of the cerebro-spinal axis that is con-
tained in the cranial cavity. It is divided into four principal parts; viz., the
cerebrum, the cerebellum, the pons Varolii, and the medulla oblongata.
The cerebrum forms the largest portion of the encephalon, and occupies a
considerable part of the cavity of the cranium, resting in the anterior and middle
foss£e of the base of the skull, and separated posteriorly from the cerebellum by
the tentorium cerebelli. About the middle of its under surface is a narrow con-
610 NERVOUS SYSTEM.
stricted portion, part of wliicli, tlie crura cerebri, is continued onwards into the
pons Varolii below, and tlirough it to the medulla oblongata and spinal cord;
whilst another portion, the crura cerebelli, passes down into the cerebellum.
The cerebellum (little brain or after brain) is situated in the inferior occipital
fosste, being separated from the under surface of the posterior lobes of the cere-
brum by the tentorium cerebelli. It is connected to the rest of the encephalon
by means of connecting bands, called crara : of these, two ascend to the cere-
brum, two descend to the medulla oblongata, and two blend together in front,
forming the pons Varolii.
The pons Varolii is that portion of the encephalon which rests upon the upper
part of the basilar process and body of the sphenoid bone. It constitutes the
bond of union of the various segments above named, receiving, above, the crura
from the cerebrum ; at the sides, the crura from the cerebellum ; and below, the
medulla oblongata.
The medulla oblongata extends from the lower border of the pons Varolii to
the upper part of the spinal cord. It lies beneath the cerebellum, resting on the
lower part of the basilar groove of the occipital bone.
Weight of the encephalon. The average weight of the brain, in the adult male,
is 49| oz., or a little more than 3 lb. avoirdupois; that of the female, 44 oz. ;
the average difference between the two being from 5 to 6 oz. The prevailing
weight of the brain, in the male, ranges between 46 oz. and 53 oz. ; and in the
female, between 41 oz. and 47 oz. In the male, the maximum weight out of
278 cases was 65 oz., and the minimum weight 34 oz. The maximum weight
of the adult female brain, out of 191 cases, was 56 oz., and the minimum weight
31 oz. It appears that the weight of the brain increases rapidly up to the
seventh year, more slowly to between sixteen and twenty, and still more slowly
to between thirty and forty, when it reaches its maximum. Beyond this period,
as age advances and the mental faculties decline, the brain diminishes slowly in
weight, about an ounce for each subsequent decennial period. These results'
apply alike to both sexes.
The size of the brain appears to bear a general relation to the intellectual
capacity of the individual. Cuvier's brain weighed rather more than 64 oz.,
that of the late Dr. Abercrombie 63 oz., and that of Dupuytren 62 J oz. On the
other hand, the brain of an idiot seldom weighs more than 23 oz.
The human brain is heavier than that of all the lower animals, excepting
the elephant and whale. The brain of the former weighs from 8 lb. to 10 lb. ;
and that of a whale, in a specimen seventy-five feet long, weighed rather more
than 5 lb.
Medulla Oblongata^
The Medulla Oblongata is the upper enlarged part of the spinal cord, and
extends from the upper border of the atlas to the lower border of the pons
Varolii. It is directed obliquely downwards and backwards; its anterior surface
rests on the basilar groove of the occipital bone, its posterior surface is received
into the fossa between the hemispheres of the cerebellum, forming the floor of
tlie fourth ventricle. It is pyramidal in form, its broad extremity directed up-
wards, its lower end being narrow at its point of connection with the cord. It
measures an inch and a quarter in length, three-quarters of an inch in breadth
at its widest part, and half an inch in thickness. Its surface is marked, in the
median line, in front and behind, by an anterior and posterior median fissure,
which arc continuous with those of the spinal cord. The anterior fissure con-
tains a fokl of ])ia mater, and terminates just below the pons in a cid-de-sac, the
foramen cajcuin. The posterior is a deep but narrow fissure, continued upwards
along the Hoof u{' ihc fourth ventricle, where it is finally lost. These two
fissures divide llic tncdnlla. iiilo lwo symmetrical halves, each lateral half being
snbdividrf] by miiior grc^ovcs into four columns, which, from before backwards.
MEDULLA OBLONGATA.
611
Fig. 354. — Medulla Oblongata and
Pons Varolii. Anterior Surface.
are named the anterior pyramid^ lateral tract and olivary hody^ the restiform hody^
the jjosterior pyramid.
The anterior pyramids^ or corpora pyramidalia^ are two pyramidal bundles
of white matter, placed one on either side of the anterior median iissure, and
separated from the olivary body, which is ex-
ternal to them, by a slight depression. At
the lower border of the pons they are somewhat
constricted ; they then become enlarged, and
taper slightly as they descend, being continuous
below with the anterior columns of the cord.
On separating the pyramids below, it will be
observed that their innermost fibres form from
four to five bundles on each side, which decus-
sate with one another; this decussation, hoA\'"-
ever, is not formed entirely of fibres from the
pyramids, but mainly from the deep portion of
the lateral columns of the cord which pass for-
wards to the surface between the diverging
anterior columns. The outermost fibres do not
decussate ; they are derived from the anterior
columns of the cord, and are continued directly
ujDwards through the pons Varolii.
• Lateral tract and olivary body. The lateral
tract is continuous with the lateral column of
the cord. Below, it is broad, and includes that
part of the medulla between the anterior pyramid and restiform body; but
above, it is pushed a little backwards, and narrowed by the projection forwards
of the olivary body.
The olivary bodies are two prominent oval masses, situated behind the anterior
pyramids, from which they are separated by slight grooves. They equal, in
breadth, the anterior pyramids, are a little broader
above than below, and are about half an inch in
length, being separated above from the pons Varolii
by a slight depression. Numerous white fibres {Jibrse
arciformes) are seen winding round the lower end of
each body, sometimes crossing their surface.
The restiform bodies (Fig. 355) are the largest
columns of the medulla, and continuous, below, with
the posterior columns of the cord. They are two
rounded, cord-like eminences, placed between the
lateral tracts, in front, and the posterior pyramids, be-
hind ; from both of which they are separated by slight
grooves. As they ascend they diverge from each other.
Fig. 355. — Posterior Surface
of the Medulla Oblongata.
assist in forming the lateral boundaries of the fourth
ventricle, and then enter the corresponding hemi-
sphere of the cerebellum, forming its inferior peduncle,
while other fibres are continued from the restiform
bodies in'^o the cerebrum.
The posterior i^yraTnids {fasciculi graciles) are two
narrow white cords placed one on each side of the
posterior median fissure, and separated from the resti-
form bodies by a narrow groove. They consist entirely
of white fibres, and are continuous with the posterior
median columns of the spinal cord. These bodies
lie, at first, in close contact. Opposite the apex of the fourth ventricle they form
an enlargement [process clavatus)^ and then, diverging, are lost in the corre-
G12 NERVOUS SYSTEM.
sponding restiform body. The upper part of tlie posterior pyramids forms the
Jateral boundaries of the calamus scriptorius.
The 'posterior surface of the medtdla oblongata forms part of the floor of the
fourth ventricle. It is of a triangular form, bounded on each side by the diverg-
ing posterior pyramids, and is that part of the ventricle which, from its resem-
blance to the point of a pen, is called the calamus scriptorius. The divergence
of the posterior pyramids and restiform bodies opens to view the gray matter
of the medulla, which is continuous, below, with the gray commissure of the
cord. In the middle line is seen a longitudinal furrow, continuous with the
posterior median fissure of the cord, terminating, below, at the point of the
ventricle, in a cul-de-sac^ the ventricle of Arantius, which descends into the
medulla for a slight extent. It is the remains of a canal, which, in the foetus,
extends thronghout the entire length of the cord,
Structure. The columns of the cord are directly continuous with those of the
medulla oblongata, below ; but, higher up, both the white and gray constituents
are rearranged before they are continued upwards to the cerebrum and cere-
bellum.
The anterior pyramid is composed of fibres derived from the anterior column
of the cord of its own side, and from the lateral column of the opposite half of
the cord, and is continued upwards into the cerebrum and cerebellum. The
cerebellar fibres form a superficial and deep layer, which pass beneath the oli-
vary body to the restiform body, and spread out into the structure of the cere-
bellum. A deeper fasciculus incloses the olivary body, and, receiving' fibres
from it, enters the pons as the olivary fasciculus or fillet ; but the chief mavss of
fibres from the pyramid, the cerebral fibres, enter the pons in their passage
upwards to the cerebrum. The anterior pyramids contain no gray matter.
The lateral tract is continuous, below, with the lateral column of the cord.
Its fibres pass in three different directions. The most external join the resti-
form body, and pass to the cerebellum. The internal, more numerous, pass for--
wards, pushing aside the fibres of the anterior column, and form part of the
opposite anterior pyramid. The middle fibres ascend, beneath the olivary body,
to the cerebrum, passing along the back of the pons, and form, together with
fibres from the restiform body, the fasciculi teretes, in the floor of the fourth
ventricle.
Olivary liody. If a transverse section is made through either olivary body,
it will be found to consist of a small ganglionic mass, deeply imbedded in the
medulla, partly appearing on the surface as a
Fig. 35fi.— Transverse Section of smooth, olive-shaped eminence (Fig. 366), It
Mednlla Oblongata. consists, externally, of white substance; and,
/i-^^mr /■/«</« F.iscicarrcrttea internally, of a gray nucleus, the corpus denta-
tum. The gray matter is arranged in the form
of a hollow capsule, open at its upper and inner
\r.t!f.rm'B<:3y part, aud presenting a zigzag or dentated out-
ii!^. „ , line. White fibres pass into, or from the inte-
^. , \ „ ,, rior of this body, by the aperture m the poste-
A^Utlcv rL6->u.r€/ Anterior Fyr^mli . . P , 1 "^ "^ 1 m) • • -i-l ^1
nor part of the capsule. They join with those
fibres of the anterior column which ascend on
the outer side, and beneath the olivary body, to form the olivary fasciculus,
which ascends to the cerebrum.
The restiform hody is formed chiefly of fibres from the posterior column of the
cord; but it receives some from the lateral column, and a fasciculus from the
anterior, and is continued, upwards, to the cerebrum and cerebellum. On enter-
ing the perns, it divides into two fasciculi, above the point of the fourth ventricle.
The external fasciculus enters the cerebellum ; the inner fasciculus joins the
posterior pyramid, is continued up along the fourth ventricle, ai\d is traced up
to the cerebrum with the fasciculi teretes.
MEDULLA OBLONGATA.
613
Septum of the raedulla oblongata. Above the decussation of tlie anterior
}3jramids, numerous white fibres extend, from behind forwards, in the median
line, forming a septum, which subdivides the medulla into two lateral halves.
Some of these fibres emerge at the anterior median fissure, and form a band
which curves round the lower border of the olivary bod v, or passes transversely
across it, and round the sides of the medulla, forming the arciforvi fibres of
Kolando. Others appear in the floor of the fourth ventricle, issuing from the
posterior median fissure, and form the white striae in that situation.
Fiff. 357.
-The Columns of the Medulla Oblongata, and their connection with the
Cerebrum uud Cerebellum.
Gray matter of the medulla oblongata. The gray matter of the medulla is a
continuation of that in the interior of the spinal cord, besides a series of special
deposits or nuclei.
In the lower part of the medulla, the gray matter is arranged as in the cord,
but at the upper part it becomes more abundant, and is disposed with less appa-
rent regularity, becoming blended with all the white fibres, except the anterior
pyraraids. The part corresponding to the transverse gray commissure of the
cord is exposed to view in the floor of the fourth ventricle, by the divergence
of the restiform bodies, and posterior . pyramids, becoming blended with the
ascending fibres of the lateral column, and thus forming the fasciculi teretes.
The lateral crescentic portions, but especially the posterior horns, become
enlarged, blend with the fibres of the restiform bodies, and form the tuhercolo
cinereo of Rolando.
Special deposits of gray matter are found both in the anterior and posterior
parts of the medulla , forming, in the former situation, the corpus dentatum
within the olivary body, and in the latter, a series of special masses, or nuclei,
connected witli the roots of origin of the spinal accessory, vagus, glosso-pha-
ryngeal, and hypoglossal nerves. It thus appears that the closest analogy in
structure, and also probably in general endowments, exists between the medulla
oblongata and the spinal cord. The larger size and peculiar form of the medulla
depend on the enlargement, divergence, and decussation of the various columns ;
and also on the addition of special deposits of gray matter in the olivary bodies
C14 NERVOUS SYSTEM.
and otlier parts, evidently in adaptation to the more extended range of function
wliicli this part of the cerebro-spinal axis possesses.
Pons Yarolii.
The Pons Yarolii {viesocephale^ Chaussier) is the bond of union of the various
segments of the encephalon, connecting the cerebrum above, the medulla ob-
longata below, and the cerebellum behind. It is situated above the medulla
oblongata, below the crura cerebri, and between the hemispheres of the cere-
bellum.
Its under surface presents a broad transverse band of white fibres, which
arches like a bridge across the upper part of the medulla, extending between
the two hemispheres of the cerebellum. This surface projects considerably
beyond the level of these parts, is of quadrangular form, rests upon the sphenoid
and basilar groove of the occipital bone, and is limited before and behind by
very prominent margins. It presents along the middle line a longitudinal
groove, wider in front than behind, which lodges the basilar artery; numerous
transverse strite are also observed on each side, which indicate the course of its
superficial fibres.
Its upper surface forms part of the floor of the fourth ventricle, and at each
side it becomes contracted into a thick rounded cord, the crus cerebelli, which
enters the substance of the cerebellum, constituting its middle peduncle.
Structure. The pons Yarolii consists of alternate layers of transverse and
longitudinal fibres intermixed with gray matter (Fig. 357).
The transverse fibres connect together the two lateral hemispheres of the cere-
bellum, and constitute its great transverse commissure. They consist of a
superficial and a deep layer. The superficial layer passes uninterruptedly
across the surface of the pons, forming a uniform layer, which consists of fibres
derived from the crus cerebelli on each side, meeting in the median line. The
deep la^'-er of transverse fibres decussates with the longitudinal fibres continued
up from the medulla, and contains much more gray matter between its fibres.
The lonyitudiaa.l fibres are continued up through the pons. 1. From the
anterior pyramid. 2. From the olivary body. 3. From the lateral and poste-
rior columns of the cord, receiving special fibres from the gray matter of the
pons itself.
1. The fibres from the anterior pyramid ascend through the pons, embedded
between two layers of transverse fibres, being subdivided in their course into
smaller bundles ; at the upper border of the pons they enter the crus cerebri,
forming its fasciculated portion.
2. The olivary fasciculus divides in the pons into two bundles, one of which
ascends to the corpora quadrigemina ; the other is continued to the cerebrum
with the fibres of the lateral column.
3. The fibres from the lateral and posterior columns of the cord, with a
bundle from the olivary fasciculus, are intermixed with much gray matter, and
appear in the floor of the fourth ventricle as the fasciculi teretes : they ascend
to the deep or cerebral part of the crus cerebri.
Fovillc believes that a few fibres from each of the longitudinal tracts of the
medulla turn forwards, and are continuous with the transverse fibres of the
pons.
Sepiurn. The pons is subdivided into two lateral halves by a median septum
which extends through its posterior half. The septum consists of antero-poste-
rior and transverse fibres. The former are derived from the floor of the fourth
ventricle and from the transverse fibres of the pons, which bond backwards
before passing across to the opposite side. The latter arc derived from the
floor of the fourth ventricle; they pierce the longitudinal fibres, and are then
continued acrcxss from one to the other side of the medulla, i)iercing the antcro-
CONVOLUTIONS OF THE BRAIN. 615
posterior fibres. The two halves of tlie pons, in front, are connected together
by transverse commissural fibres.
Cerebrum. Upper Surface. (Fig. 358.)
The Cerebrum, in man, constitutes the largest portion of the encephalon.
Its upper surface is of an ovoidal form, broader behind than in front, convex in
its general outline, and divided into two lateral halves or hemispheres, right
and left, by the great longitudinal fissure, which extends throughout the entire
length of the cerebrum in the middle line, reaching down to the base of the
brain in front and behind, but interrupted in the middle by a broad transverse
commissure of white matter, the corpu-s callosum, which connects the two hemi-
spheres together. This fissure lodges the falx cerebri, and indicates the original
development of the brain by two lateral halves.
Each hemisphere presents an outer surface, which is convex, to correspond
with the vault of the cranium ; an inner surface, flattened, and in contact with
the opposite hemisphere (the two inner surfaces forming the sides of the longi-
tudinal fissure) ; and an under surface or base, of more irregular form, which
rests, in front, on the anterior and middle fossae at the base of the skull, and
behind, upon the tentorium.
Convolutions. If the pia mater is removed with the forceps, the entire surface
of each hemisphere will be seen to present a number of convoluted eminences,
the convolutions^ separated from each other by depressions (sulci) of various
depths. The outer surface of each convolution, as well as the sides and bottom
of the sulci between them, are composed of gray matter, which is here called
the cortical substance. The interior of each convolution is composed of white
matter ; and white fibres also blend with the gray matter at the sides and bot-
tom of the sulci. By this arrangement the convolutions are adapted to increase
the amount of gray matter without occupying much additional space, while
they also afford a greater extent of surface for the termination of the white
fibres in gray matter. On closer examination, however, the cortical substance
is found subdivided into four layers, two of which are composed of gray and
two of white matter. The most external is an outer white stratum, not equally
thick over all parts of the brain, being most marked on the convolutions in the
longitudinal fissure and on the under part of the brain, especially on the middle
lobe, near the descending horn of the lateral ventricle. Beneath this is a thick
reddish-gray lamina, and then another thin white stratum ; lastly, a thin stratum
of gray matter, which lies in close contact with the white fibres of the hemi-
spheres : consequently white and gray laminae alternate with one another in
the convolutions. In certain convolutions, however, the cortical substance
consists of no less than six laj^ers, three gray and three white, an additional
white stratum dividing the most superficial gray one into two ; this is especially
marked in those convolutions which are situated near the corpus callosnm.
There is no accurate resemblance between the convolutions in different brains,
nor are they symmetrical on the two sides of the same brain. Occasic^nally the
free borders or the sides of a deep convolution present a fissured or notched
appearance.
The sulci are generally an inch in depth ; they also vary in different brains,
and in different parts of the same brain ; they are usually deepest on the outer
convex surface of the hemispheres ; the deepest is situated on the inner sur-
face of the hemisphere, on a level with the corpus callosum, and corresponds to
the projection in the posterior horn of the lateral ventricle, the hippocampus
minor.
The number and extent of the convolutions, as well as their depth, appear to
bear a close relation to the intellectual power of the individual, as is shown in
their increasing complexity of arrangement as we ascend from the lowest mam-
malia up to man. Thus they are absent in some of the lower order of mam-
616 NERVOUS SYSTEM.
malia, and tliey increase in number and extent tlirongli the liiglier orders. In
man tliej' present the most complex arrangement. Again, in the child at birth
before the intellectual faculties are exercised, the convolutions have a very-
simple arrangement, presenting few undulations ; and the sulci between them
are less deep than in the adult. In old age, when the mental faculties have
diminished in activity, the convolutions become much less prominently marked.
The convolutions on the outer convex surface of the hemisphere, the general
direction of which is more or less oblique, are the largest and most complicated
convolutions of the brain, frequently becoming branched like the letter Y in
their course upwards and backwards towards the longitudinal fissure: these
convolutions attain their greatest development in man, and are especially charac-
teristic of the human brain. They are seldom symmetrical on the two sides.
Each hemisphere of the brain is divided into five lobes, the division being
made by the main fissures, and by imaginary lines drawn to connect them.
This division, however, is only traceable on the external surfiace of the hemi-
spheres.
In this description of the divisions of the brain, the first point to be remem-
bered is the external termination of the fissure of Sylvius. That fissure bifur-
cates, one branch running forwards into the anterior lobe, the other, the longer
one, running nearly horizontally backwards. An imaginary line, continuing
this branch backwards to the posterior lobe, separates from the middle lobe a
few convolutions which fill up the hollow of the middle fossa of the skull, and
these are called the temporo-sphenoidal lobe (Fig. 360). This, added to the old
anterior, middle, and posterior lobes (now renamed frontal, parietal, and occipi-
tal), and to the island of Reil, now described as a separate lobe, raises the number
of lobes from three to five. The subdivision is made by fissures which are tole-
rably distinct. Thus the separation between the anterior, or frontal, and the
parietal lobe at the base, by the fissure of Sylvius, is obvious, and the large
vertical fissure (fissure of Rolando, Fig. 368) which separates the frontal from
the parietal lobe at the vertex is usually very plainl};^ marked, and runs down
nearly to the posterior bifurcation of the Sylvian fissure. The parietal lobe is
separated from the occipital above by the parieto-occipital fissure (Fig. 358),
which becomes indistinct below; and the separation is completed by an imagi-
nary line which meets another imaginary line, by which the posterior bifur-
cation of the fissure of Sylvius is continued backwards, and by the junction of
these two lines the lowest or temporo-sphenoidal lobe is bounded ofi:' from the
upper parts of the parietal and occipital lobes.
The chief convolutions whicli bound these several fissures are pretty constant,
but the secondary convolutions, or those which form the bulk of the several
lobes, vary greatly in their number and arrangement.
The convolntion of the corpus callosum [gyrus fornicatus^ Fig. 359) is always
well marked. It lies parallel with the upper surface of the corpus callosum,
commencing, in front, on the under surface of the brain in front of the anterior
perforated space; it winds round the curved border of the corpus callosum, and
passes along its upper surface as far as its posterior extremity, where it is con-
nected with the convolutions of the posterior lobe ; it then curves downwards
and forwards, embracing the cerebral peduncle, passes into the middle lobe,
forming the hippocampus major, and terminates just behind the point from
whence it arose.
The sv.jiraorhital convolution on the uiid(;r surface of the anterior lobe is well
marked.
The Convolution of tlte l/m(jitudinal fissure (Fig. 358) bounds the margin of the
fissure on the upper surface of the hemisphere. It commences on the under
surface of the brain, at the anterior perforated spot, passes forwards along the
inner margin of tlic anterior lobe, being here divided by a deep sulcus, in which
the olfactory nerve is received ; it th(>n curves over the anterior {inrl upper su7'fiice
of the hemisphere, along the margin of the longitudinal fissure, to its posterior
CONVOLUTIONS OF THE BRAIN.
617
extremity, wliere it curves forwards along the under, surface of tlie liemisplierc
as far as the middle lobe.
The convolutions seen on the outer side of the frontal lobe are described as an
ascending or transverse frontal convolution, which lies parallel to and in front
of the fissure of Eolando, and three more or less horizontal convolutions, the
superior, middle, and inferior frontal (Fig. 358).
Fig. 358. — Upper Surface of the Brain, the Pia Mater having been removed.
Great ZonffiluJinal T'lssur/:
Infr Frontal Conv.
Asc. Frontal
C071V.
Fiss7tre of
Rolando
Asc. Parietal
Conv.
Lit. Parietal
F'issure
Siipramarginal
Conv.
Angular Conv.
Pa riet o - Occip ' I
Fissnre^
Middle Occ'l Conv.
Infr Occ'l Conv.
The external surface of the parietal lobe is fortned in front by a convolution
lying parallel to and behind the fissure of Rolando, named the ascending parietal.,
which usually joins the ascending frontal either above or below. Its central
and lower part is bounded behind by the inter -parietal fissure., a fissure which com-
mences below in or near the fissure of Sylvius, and runs upwards to the vertex,
where it terminates in or near the parieto-occipital fissure. The group of con-
volutions connected with the upper part of the ascending parietal, and lying in
front of the interparietal fissure, is called the superior parietal lobule. Lower
down, and lying behind the inter-parietal fissure, is the lower parietal lobule,
divided into the supra-marginal and the angular convolution, which run into each
other above andbeloAv. The angular convolution is continuous with the convo-
lutions of the temporo-sphenoidal and occipital lobes.
' In the specimen from which this figure was drawn, the parieto-occipital fissure has been
bridged over, or obliterated, by one of the annectant convolutions of the occipital lobe, but its
continuation can be traced on the internal aspect of the hemisphere. (See Fig. 359.)
G18
NERVOUS SYSTEM.
The occipital lobe is cliiefly formed by three somewhat parallel convolutions,
the superior, middle, and inferior, separated by two fissures, the superior and in-
ferior occipital. The occipital convolutions are connected with the superior
parietal lobule, with the angular convolution, and with the temporo-sphenoidal
lobe, bj various convolutions termed annectant^ described as four in number.
The convolutions of the temporo-sphenoidal lobe are three : a suj^erior^ Ijii^g
behind or internal to the posterior branch of the Sylvian fissure ; a middle.
continuous with the angular and middle occipital convolution : and an inferior.^
continuous w^ith the inferior occipital.
Fig. 359. — Vertical Median Sectiou of the Euceplialon, showing the parts in the middle line.
7.
Convolution of corpus callosum. Ahove it is the cal-
li. so-marginal fissure, luuniug out at 2 to join the
fissure of llolando.
The parieto-occipital fissure.
4 point to the calcarine fissure, which is just above the
numbers. Between 2 and 3 are the onvolutions of
thf quadrate lobe. Between 3 and 4 is the cuneate
lobp.
The corpus callosum.
Tlie s-eptum lucidum.
Tlie forni.x.
Anterior pillar of the fornix, descendinfj to the baso of
the brain, and turninir on itself to form the corpus
albicans, its course to the optic thalamus is indi-
cated by a dottid line.
The optic thalamus, in front of the number and be-
hind the anterior cms of the fornix, a shaded part
indicates the forjimon of Monro ; behind tlie number
au oval marlv shows the position of the gray matter
continnous with the middle commissure.
10. The velum interpositum.
1 1. Tlie pineal gland.
12. The corpora quadrigemina.
13. Tlie crus cerebri.
14. The valve of Vieussens (above tho number).
1">. The pons Varolii.
lii. The third nerve.
17. Tho pituitary body.
18. Tlie optic nerve.
19 points to the anterior commissure, indicated by an
oval mark behind the nnuibor.
At the point where the Sylvian fissure bifurcates is found the commencement
of the island of Eeil, the fifth lobe of the brain, a triangular-shaped prominent
cluster of a1)out six convolutions, the (jyTi operti^ so called from being covered
in by the sides of the fissure. They arc continuous wilh tliosc of the frontal,'
parietal, and temporo-sphenoidal lobes. By the removal of tlicse convolutions
the cxtraventricular part of the corpus striatum would be reached.
On the inner, or median, surface of the hemispheres there is no division into
lobes, and the arrangement of the convolutions is less complex (Fig. 351)). IMio
termination of the paricto-oocipital fissure will be seen at the ]')(isterior part, and
joining this near the posterior extremity of the corpus callosum is another
BASE OF THE BRAIN. 619
fissure, the calcarine^ wliicli commences usually by two branclies at tlie back of
the hemisphere, and runs horizontally to join the parieto-occipital fissure.
Between it and the latter fissure a wedge-shaped mass of convolutions (the
cuneate lobule) is seen. Another fissure, the calloso-marginal fissure, is seen in
front, commencing near the anterior extremity of the corpus callosum, and
bounding the gyrus fornicatus above. This runs upwards and backwards to
fall into the extremity of the fissure of Eolando. Between it and the parieto-
occipital fissure is a somewhat square-shaped assemblage of convolutions — the
Iphulus guadratus or preecuneus. The space between the gyrus fornicatus and
'the convolution of the longitudinal fissure on this aspect of the brain is occupied
by various secondary convolutions, which need not be particularly described.
Besides tlie great primary convolutions above named and described, and
which can be recognized in almost any well-developed brain, there are a great
number of these secondary convolutions which pass from one to another of the
primary, and often somewhat obscure their arrangement; of these, the annectant
convolutions of the occipital lobe, above mentioned, may be taken as examples.
Ceeebrum. Uxder Surface of Base. (Fig. 360.)
The under surface of each hemisphere presents a subdivision, as already
mentioned, into three lobeSj named from their position, anterior, middle, and
posterior.
The anterior OT frontal lohe^ of a triangular form, with its apex backwards,
is somewhat concave, and- rests upon the convex surface of the roof of the orbit,
being separated .from the middle lobe by the fissure of Sylvius. The middle
lohe^ which is more prominent, is received into the middle fossa of the base of
the skull, and comprises the parietal and temporo-sphenoidal lobes. l^h.Q pos-
terior or occipital lohe rests upon the tentorium, its extent forwards being limited
by the anterior margin of the cerebellum.
The various objects exposed to view on the under surface of the cerebrum,
in and near the middle line, are here arranged in the order in which they are
met with from before backwards.
Longitudinal fissure. Tuber cinereum.
Corpus callosum and its peduncles. Infundibulum.
Lamina cinerea. Pituitary body.
Olfactory nerve. Corpora albicantia.
Fissure of Sylvius. Posterior perforated space.
Anterior perforated space. Crura cerebri.
Optic commissure.
The longitudinal fissure partially separates the two hemispheres from one
another: it divides the two anterior lobes in front; and on raising the cere-
bellum and pons, it will be seen completely separating the two posterior lobes,
the intermediate portion of the fissure being filled up by the great transverse
band of white matter, the corpus callosum. Of these two portions of the
longitudinal fissure, that which separates the posterior lobes is the longest. In
the fissure between the two anterior lobes the anterior cerebral arteries may be
seen ascending to the corpus callosum ; and at the back part of this portion of
the fissure, the anterior curved portion of the corpus callosum descends to the
base of the brain.
The corpus callosttm, terminates at the base of the brain by a concave margin,
which is connected with the tuber cinereum through the intervention of a thin
layer of gray substance, the lamina cinerea. This may be exposed by gently
raising and drawing back the optic commissure. A broad white band may
be observed on each side, passing from the under surface of the corpus callosum
backwards and outwards, to the commencement of the fissure of Sylvius ; these
620
NERVOUS SYST'EM.
bands are called tlie peduncles of the corpus callosum. Laterally, tlie corpus
callosum extends into the anterior lobe.
The lamina cmerea is a thin layer of gray substance, extending backwards
above the optic commissure from the termination of the coryjus callosum to the
tuber cinereum; it is continuous on either side with the gray matter of the
anterior perforated space, and forms the anterior part of the inferior boundary
of the third ventricle. It connects the genu, or reflected portion, of the corpus
callosum with the optic commissure, and is on this account described by Sappey
as the gray root of the optic nerves.
The olfactory nerve^ with its bulb, is seen on either side of the longitudinal
fissure, upon the under surface of each anterior lobe.
The fissure of Sylvius separates the anterior and middle lobes, and lodges
the middle cerebral artery. At its commencement is seen a point of medullary
substance, corresponding to a subjacent band of white fibres, connecting the
anterior and middle lobes, and called the fasciculus unciformis ; on following
this fissure outwards, it divides into two branches, which inclose the triangular-
shaped prominent cluster of isolated convolutions {gyri operti) called the island
of Reil.
360. — Base of the Brain.
Lobe
FarietrilLobe
Posfr
Divlsioyi of
Ivia n l-'/ss7t re
Temporo-
sphenoidal
Lobe
—Occipilal Lobe.
The anterior perforated space is situated at llic inner side of the fissure of
Sylvius. It is of a triangular shape, bounded in front by the convolutions of the
anterior lobe and the roots of the olfactory nerve; behind, by the optic tract;
BASE OF THE BRAIN. G21
externally, by tlie middle lobe and commencement of the fissure of Sylvius;
internally, it is continuous witb the lamina cinerea, and crossed by the peduncle
of the corpus callosum. It is of a grayish color, and corresponds to the under
surface of the corpus striatum, a large mass of gray matter, situated in the inte-
rior of the brain ; it has received its name from being perforated by numerous
minute apertures for the transmission of small straight vessels into the sub-
stance of the corpus striatum.
The optic commissure is situated in the middle line, immediately behind the
lamina cinerea. It is the point of junction between the two optic nerves.
Immediately behind the diverging optic tracts, and between them and the
peduncles of the cerebrum {crura cerehi)^ is a lozenge-shaped interval, the inter-
peduncular space, in which are found the following parts, arranged in the follow-
ing order from before backwards : the tuber cinereum, infundibulum, pituitary
body, corpora albicantia, and the posterior perforated space.
The tuher cinereum is an eminence of gray matter, situated between the optic
tract and the corpora albicantia : it is connected with the surrounding parts of
the cerebrum, forms part of the floor of the third ventricle, and is continuous
with the gray substance in that cavity. From the middle of its under surface a
conical tubular process of gray matter, about two lines in length, is continuous
downwards and forwards to be attached to the posterior lobe of the pituitary
body; this is the infundibulum. Its canal, which is funnel-shaped, communi-
cates with the third ventricle.
The pituitary body is a small reddish-gray vascular mass, weighing from five
to ten grains, and of an oval form, situated in the sella Turcica, in connection
with which it is retained by the dura mater forming the inner wall of the caver-
nous sinus. It is very vascular, and consists of two lobes, separated from one
another by a fibrous lamina. Of these, the anterior is the larger, of an oblong
form, and somewhat concave behind, where it receives the posterior lobe, which
is round. The anterior lobe consists externally of a firm yellowish-gray sub-
stance, and internally of a soft pulpy substance of a yellowish- white color. The
posterior lobe is darker than the anterior. In the foetus it is larger proportion-
ally than in the adult, and contains a cavity which communicates through the
infundibulum with the third ventricle. In the adult it is firmer and more solid,
and seldom contains any cavity. Its structure, especially the anterior lobe, is
similar to that of the ductless glands.
The corpora albicantia are two small round white masses, each about the size
of a pea, placed side by side immediately behind the tuber cinereum. They are
formed by the anterior crura of the fornix, hence called the hulls of the fornix^
which, after descending to the base of the brain, are folded upon themselves,
before passing upwards to the thalami optici. They are composed externally of
white substance, and internally of gray matter ; the gray matter of the two being
connected by a transverse commissure of the same material. At an early period
of foetal life they are blended together into one large mass, but become separated
about the seventh month.
^]iQ posterior perforated space [pons Tarini) corresponds to a whitish-gray sub-
stance, placed between the corpora albicantia in front, the pons Yarolii behind,
and the crura cerebri on either side. It forms the back part of the third ven-
tricle, and is perforated by numerous small orifices for the passage of blood-
vessels to the thalami optici.
The crura cerebri {peduncles of the cerebrum) are two thick cjdindrical bundles
of white matter, which emerge from the anterior border of the pons, and diverge
as they pass forwards and outwards to enter the under part of either hemisphere.
Each crus is about three-quarters of an inch in length, and somewhat broader
in front than behind. They are marked upon their surface with longitudinal
stri^, and each is crossed, just before entering the hemisphere, by a flattened
white band, the optic tract, which is adherent by its upper border to the
peduncle. In the interior of the crura is contained a mass of dark a:ray matter,
622 NERVOUS SYSTEM.
called locus niger. The third nerves may be seen emerging from the inner side
of either eras, and the fourth nerve winding round its outer side from above.
Each crus consists of a superficial and deep layer of longitudinal white fibres,
continued u^pwards from the pons : these layers are separated from each other by
the locus niger.
The superficial longitudinal fihres are continued upwards, from the anterior
pyramids to the cerebrum. They consist of coarse fasciculi, which form the free
part of the crus, and have received the name of the fasciculated portion or crusta
of the peduncle.
The deep longitudinal fihres are continued upwards, in two layers, one from the
lateral and posterior columns of the medulla and one from the olivary fasciculus,
these fibres consisting of some derived from the same, and others from the
opposite lateral tract of the medulla. More deeply, are finer fibres, mixed with
gray matter, derived from the cerebellum, blended with the former. The
cerebral surface of the crus cerebri is formed of these fibres, and is named the
tegmentum.
The locus niger is a mass of gray matter, situated between the superficial and
deep layers of fibres above described. It is placed nearer the inner than the
outer side of the crus.
The posterior lobes of the cerebrum are concealed from view by the upper
surface of the cerebellum, and pons Varolii. When these parts are removed, the
two hemispheres are seen to be separated by the great longitudinal fissure, this
fissure being interrupted, in front, by the posterior rounded border of the corpus
callosum.
Gexeeal Arkaxgement of the Parts composixg the Cerebrum.
As the peduncles of the cerebrum enter the hemispheres, they diverge from
one another, so as to leave an interval between them, the interpeduncular space.
As they ascend, the component fibres of each pass through two large masses of
gray matter, the ganglia of the brain, called the thalamus opticus and cordons
striatum, which project as rounded eminences from the upper and inner side of
each peduncle. The hemispheres are connected together, above these masses,
by the great transverse commissure, the corpus callosum, and the interval left
between its under surface, the upper surface of the ganglia, and the parts closing
the interpeduncular space, forms the general ventricular cavity. The upper
part of this cavity is subdivided into two by a vertical septum, the septum
lucidura ; and thus the two lateral ventricles are formed. The lower part of
the cavity forms the third ventricle, which communicates with the lateral
ventricles above, and with the fourth ventricle behind. The fifth ventricle is
the interval left between the two layers composing the septum lucidum.
Interior of the Cerebrum.
If the upper part of either hemisphere is removed with a scalpel, about half
an inch above the level of the corpus coUosum, its internal white matter will be
exposed. It is an oval-shaped centre, of white substance, surrounded on all sides
by a narrow convoluted margin' of gray matter which presents an equal thick-
ness in nearly every part. ^.Phis white central mass has been called the centrum
ovale minus. Its surface is studded with numerous minute red dots {puncta
vasculosa), produced by the escape of blood from divided bloodvessels. In
inflammation or great congestion of the brain, these are very numerous, and of
a dark color. If the remaining portion of one hemisphere is slightly separated
from the other, a broad band oF white substance will be observed connecting
them, at the bottom of the longitudinal fissure ; this is the corpus callosum.
The margins of the hemispheres, Avhich overlap this portion of the bram, are
called the lahia cerehri. Each labiiiin is part of the convolution of the corjius
CEREBRUM.
623
callosum {gyrus fornicatus), already described ; and the space between it and tlic
upper surface of the corpus callosum has been termed the ventricle of the corpus
callosum.
The hemispheres should now be sliced off, to a level with the corpus callosum,
when the white substance of that structure will be seen connecting together both
hemispheres. The large expanse of medullary matter now exposed, surrounded
by the convoluted margin of gray substance, is called the centrum ovale majus
of Vieussens,
The corjius callosum is a thick stratum of transverse fibres, exposed at the
bottom of the longitudinal fissure. It connects the two hemispheres of the brain,
forming their great transverse commissure ; and forms the roof of a space in the
interior of each hemisphere, the lateral ventricle. It is about four inches in
lenofth, extending to within an inch and a half of the anterior, and to within
two inches and a half of the posterior, part of the brain. It is somewhat broader
behind than in front, and is thicker at either end than in its central part, being
Fig. 361. — Section of the Brain. Made on a level with the Corpus Callosum.
thickest behind. It presents a somewhat arched form, from before backwards,
terminating anteriorly in a rounded border, which curves downwards and back-
wards, between the anterior lobes to the base of the brain. In its course, it
forms a distinct bend, named the knee or genu^ and the reflected portion, named
the heah [rostrum)^ becoming gradually narrower, is attached to the anterior
cerebral lobe, and is connected through the lamina cinerea with the optic com-
missure. The reflected portion of the corpus callosum gives off, near its termi-
nation, two bundles of white substance, which, diverging from one another, pass
624
NERVOUS SYSTEM.
backwards, across tlie anterior perforated space, to tlie entrance of tlie fissure
of Sylvius. Tiiej are called the peduncles of the corpus callosum. Posteriorly,
the corpus callosum forms a thick rounded fold, which is free for a little distance,
as it curves forwards, and is then continuous with the fornix. On its upper
surface, its fibrous structure is very apparent to the naked eye, being collected
into coarse transverse bundles. Along the middle line is a linear depression,
the raphe, bounded laterally by two or more slightly elevated longitudinal bands,
called the strise Longitudinales^ or nerves of Lancisi ; and, still more externally,
other longitudinal strias are seen, beneath the convokitions which rest on the
corpus callosum. These are the strise longitudinales laterales. The under sur-
face of the corpus callosum is continuous behind with the fornix, being sepa-
rated from it in front by the septum lucidum, wliich forms a vertical partition
between the two ventricles. On either side, the fibres of the corpus callosum
penetrate into the substance of the hemispheres, and connect together the ante-
rior, middle, and part of the posterior lobes. It is the large number of fibres
derived from the anterior and posterior lobes which explains the great thickness
of the two extremities of this commissure.
An incision should now be made through the corpus callosum, on either side of the raphe,
■when two large irregular-shaped cavities will be exposed, wliich extend through a great part of
the length of each hemisphere. These are the lateral ventricles.
Fig. 362. — The Lateral Yentricles of the Brain.
The latpral ventricles arc serous cavities, formcMl by the uj'jj'icr j^art of tlie
general ventricular si)acc in the interior of the brain. They are lined by a thin
diaphanous lining membrane, covered with ciliated c])ithelinm, and moistened
by a serous fli.iid, which is sometimes, even in health, secreted in consldci'ablc
LATERAL VENTRICLES. G2o
quantity. These cavities are two in number, one in each hemisphere, and they
are separated from each other by a vertical septum, the septum lucidum.
Each lateral ventricle consists of a central cavity, or body, and three smaller
cavities or cornua, which extend from it in different directions. The anterior
cornu curves forwards and outwards into the substance of the anterior lobe.
The posterior cornu, called the digital cavity^ curves backwards into the posterior
lobe. The middle cornu descends into the middle lobe.
The central cavity^ or body of the lateral ventricle, is triangular in form. It
is bounded, above, by the under surface of the corpus callosum, which forms the
roof of the cavity. Internally, is a vertical partition, the septum lucidum,
which separates it from the opposite ventricle, and connects the under surface
of the corpus callosum with the fornix. Its floor is formed by the following
parts, enumerated in their order of position, from before backwards : the corpus
striatum, taenia semicircularis, thalamus opticus, choroid plexus, corpus fimbri-
atum, and fornix.
The anterior cornu is triangular in form, passing outwards into the anterior
lobe, and curving round the anterior extremity of the corpus striatum. It is
bounded above and in front, by the corpus callosum ; behind, by the corpus
striatum.
The posterior cornu^ or digital cavity, curves backwards into the substance of
the posterior lobe, its direction being backwards and outwards, and then in-
wards. On its floor is seen a longitudinal eminence, which corresponds with a
deep sulcus, between two convolutions : this is called the hippocavipus minor.
Between the middle and posterior horns a smooth eminence is observed, which
varies considerably is size in different subjects. It is called the eminentia col-
lateralis.
The corpus striatum has received its name from the striped appearance
which its section presents, in consequence of diverging white fibres being mixed
with the gray matter which forms the greater part of its substance. The intra-
ventricular portion is a large pear-shaped mass, of a gray color externally ; its
broad extremity is directed forwards, into the fore part of the body, and anterior
cornu of the lateral ventricle: its narrow end is directed outwards and back-
wards, being separated from its fellow by the thalami optici : it is covered by
the serous lining of the cavity, and crossed by some veins of considerable size.
The extraventricular portion is imbedded in the white substance of the hemi-
sphere.
The tsenia semicircularis is a narrow, whitish, semi-transparent band of
medullary substance, situated in the depression between the corpus striatum
and thalamus opticus. Anteriorly, it descends in connection with the anterior
pillar of the fornix ; behind, it is continued into the descending horn of the
ventricle, where it becomes lost. Its surface, especiallj^ at its fore-part, is trans-
parent, and dense in structure, and this was called by Tarinus the horny hand.
It consists of longitudinal white fibres, the deepest of which run between the
corpus striatum and thalamus opticus. Beneath it is a large vein [vena corporis
striati), which receives numerous small veins from the surface of the corpus
striatum and thalamus opticus, and joins the vense Galeni.
The choroid plexus is a highly vascular, fringe like membrane, occupying the
margin of the fold of pia mater {vehtm interpositum)^ in the interior of the brain.
It extends, in a curved direction, across the floor of the lateral ventricle. In
front, where it is small and tapering, it communicates with the choroid plexus
of the opposite side, through a large oval aperture, the fora.men of Monro.
Posteriorly, it descends into the middle horn of the lateral ventricle, where it
joins with the pia mater through the transverse fissure. In structure, it consists
of minute and highly vascular villous processes, the villi being covered by a
single layer of epithelium, composed of large round corpuscles, containing,
besides a central nucleus, a bright yellow spot. The arteries of the choroid
plexus enter the ventricle at the descending cornu, and, after ramifying through
40
626
NERVOUS SYSTEM.
its substance, send branches into the substance of the brain. The veins of the
choroid plexus terminate in the vense Graleni.
The corpus fimhriatum {tsenia hippocampi) is a narrow, wTaite, tape-like band,
situated immediately behind the choroid plexus. It is the lateral edge of the
posterior pillar of the fornix, and is attached along the inner border of the
hippocampus major as it descends into the middle horn of the lateral ventricle.
It may be traced as far as the pes hippocampi.
The thalami opiici e^ndi fornix will be described when more completely ex-
posed, in a later stage of the dissection of the brain.
The middle eornu should now be exposed, throughout its entire extent, by introducing the
little finger gently into it, and cutting outwards along the finger through the substance of the
hemisphere, which should be removed, to an extent sufficient to expose the entire cavity.
The middle^ or descending cornu^ the largest of the three, traverses the middle
lobe of the brain, forming in its course a remarkable curve round the back of
the optic thalamus. It passes, at first, backwards, outwards, and downwards, ■
and then curves round the crus cerebri, forwards and inwards, nearly to the
Fig. 363.— The Fornix, Yelum Interpositum, and Middle or Descending Cornu of the
Lateral Ventricle.
point of the middle lobe, close to the fissure of Sylvius. Its upper boundary is
formed by the medullary substance of the middle lobe, and the under surface
of the thalamus opticus. Its lower boundary, or floor, presents for examination
the following parts: the hippocampus major, pes hippocampi, pes accessorius,
corpus fimljriatuin, choroid plexus, fascia dentata, transverse fissure.
HIPPOCAMPUS MAJOR. 627
Tlie Mppocam^pus major ^ or cormi Ammonis, so called from its resemblance to a
ram's horn, is a wliite eminence, of a curved elongate form, extending along the
entire length of the floor of the middle horn of the lateral ventricle. At its lower
extremity it becomes enlarged, and presents a number of rounded elevations with
intervening depressions, which, from presenting some resemblance to the paw
of an animal, is called the pes hippocampi. If a transverse section is made
through the hippocampus major, it will be seen that this eminence is the inner
surface of the convolution of the corpus callosum, doubled upon itself like a horn,
the white convex portion projecting into the cavity of the ventricle; the gray
portion being on the surface of the cerebrum, the edge of which, slightly in-
dented, forms the fascia dentata. The white matter of the hippocampus major
is continuous, through the corpus fimbriatum, with the fornix and cor23us cal-
losum.
The pes accessoriiis^ or eminentia collateralis., has already been mentioned, as
a white eminence, varying in size, placed between the hippocampus major and
hippocampus minor, at the junction of the posterior with the descending cornu.
Like the hippocampi, it is formed of white matter corresponding to one of the
sulci, between two convolutions protruding into the cavity of the ventricle.
The corpus pmhriatura is a continuation of the posterior pillar of the fornix,
prolonged, as already mentioned, from the central cavity of the lateral ventricle.
Fascia dentata. On separating the inner border of the corpus fimbriatum
from the choroid plexus, and raising the edge of the former, a serrated band of
gray substance, the edge of the gray substance of the middle lobe, will be seen
beneath it; this is the fascia dentata. Correctly speaking, it is placed external
to the cavity of the descending cornu.
The transverse fissure is seen on separating the corpus fimbriatum from the
thalamus opticus. It is situated beneath the fornix, extending from the middle
line behind, downwards on either side, to the end of the descending cornu, being
bounded on one side by the fornix and the hemisphere, and on the other by the
thalamus opticus. Through this fissure the pia mater passes from the exterior
of the brain into the ventricles, to form the choroid plexuses. Where the pia
mater projects into the lateral ventricle, beneath the edge of the fornix, it is
covered by a prolongation of the lining membrane, which excludes it from the
cavity.
The septum lucidum (Fig. 362) forms the internal boundary of the lateral
ventricle. It is a thin, semi-transparent septum, attached, above, to the under
surface of the corpus callosum ; below, to the anterior part of the fornix ; and,
in front of this, to the prolonged portion of the corpus callosum. It is trian-
gular in form, broad in front, and narrow behind, its surfaces looking towards
the cavities of the ventricles. The septum consists of two laminae, separated by
a narrow interval, the fifth ventricle.
Fifth Ventricle. Each lamina of the septum lucidum consists of an internal
layer of white substance, covered by the lining membrane of the fifth ventricle ;
and an outer layer of gray matter, covered by the lining membrane of the lateral
ventricle. The cavity of the fifth ventricle is lined by a serous membrane,
covered with the epithelium, and contains fluid. In the foetus, and in some
animals, this cavity communicates, below, with the third ventricle ; but in the
adult, it forms a separate cavity. In cases of serous effusion into the ventricles,
the septum is often found softened and partially broken down.
The fifth ventricle maybe exposed by cutting through the septum, and attached portion of the
corpus callosum, with scissors; after examining which, the corpus callosum should be cut across,
towards its anterior part, and the two portions carefully dissected, the one forwards, the other
backwards, when the fornix will be exposed.
The fornix (Figs. 362, 363) is a longitudinal lamella of white fibrous matter,
situated beneath the- corpus callosum, with which it is continuous behind, but
separated from it in front by the septum lucidum. It may be described as
consisting of two symmetrical halves, one for either hemisphere. These two
628 NERVOUS SYSTEM.
portions are joined together in the middle line, where they form the body, but
are separated from one another in front and behind ; forming the anterior and
posterior crura.
The hody of the fornix is triangular ; narrow in front, broad behind. Its
upper surface is connected, in the median line, to the septum lucidum in front,
and the corpus callosnm behind. Its under surface rests ujion the velum inter-
positum, which separates it from the third ventricle, and the inner portion of
the optic thalami. Its lateral edges form, on each side, part of the floor of the
lateral ventricles, and are in contact with the choroid plexuses.
The anterior crura arch downwards towards the base of the brain, separated
from each other by a narrow interval. They are composed of white fibres,
which descend through a quantity of gray matter in the lateral walls of the
third ventricle, and are placed immediately behind the anterior commissure.
At the base of the brain, the white fibres of each crus form a sudden curve upon
themselves, spread out and form the outer part of the corresponding corpus albi-
cans, from which point they may be traced upwards into the substance of the
corresponding thalamus opticus (Fig. 359). The anterior crura of the fornix are
connected in their course with the optic commissure, the white fibres covering
the optic thalamus, the peduncle of the j)ineal gland, and the superficial fibres of
the t£enia semicircularis.
^h.e posterior crura^ at their commencement, are intimately connected by their
upper surfaces with the corpus callosum ; diverging from one another, they pass
downwards into the descending horn of the lateral ventricle, being continuous
with the concave border of the hippocampus major. The lateral thin edges of
the posterior crura have received the name corpus fiwhriatum^ already described.
On the under surface of the fornix, towards its posterior part, between the
diverging posterior crura, may be seen some transverse lines, and others longi-
tudinal or oblique. This appearance has been termed the lyra^ from the fancied
resemblance it bears to the strings of a harp.
Between the anterior pillars of the fornix and the anterior extremities of the
thalami optici, an oval aperture is seen on each side, the foramen of Monro.
The two openings descend towards the middle line, and joining together, lead
into the upper part of the third ventricle. These openings communicate with
the lateral ventricles on each side, and below with the third ventricle.
Divide the fornix across anteriorly, and reflect the two portions, tlie one forwards, the other
backwards, when the velum interpositum will be exposed.
The velum interpositum (Fig, 363) is a vascular membrane, reflected from the
pia mater into the interior of the brain through the transverse fissure, passing
beneath the posterior rounded border of the corpus callosum and fornix, and
above the corpora quadrigemina, pineal gland, and optic thalami. It is of a
triangular form, and separates the under surface of the body of the fornix from
the cavity of the third ventricle. Its posterior border forms an almost complete
investment for the pineal gland. Its anterior extremity, or apex, is bifid; each
bifurcation being continued into the corresponding lateral ventricle, behind the
anterior crura of the fornix, forming the anterior extremity of the choroid
plexus. On its under surface are two vascular fringes, which diverge from each
other behind, and project into the cavity of the third ventricle. Tlicse are the
choroid plexuses of the third ventricle. To its lateral margins arc connected
the choroid plexuses of the lateral ventricles. The arteries of the velum inter-
positum enter from behind, beneath the corpus callosum. Its veins, the vense
Galeni, two in nninber, run along its under surface; Ihey are formed by the
vena? corporis striati and the veins of tlic choroid ])lexuscs; the venai Galeni
unite posteriorly into a single trunk, which terminates in the straight sinus.
Tlic vclmn interpositum sliould now bo removed. Tliia mnst he effected cnrefnlly, especially
at its p(JStcrior part. wIutc it invests the pineal frhuid ; the tliahtini optici will then be exposed
with the cavity of the third ventricle between them (Fig. 364).
THALAMUS OPTICUS.
629
The thalami optici are two large oblong masses, placed between the diverging
portions of the corpora striata ; they are of a white color superficially ; inter-
nally they are composed of white fibres intermixed with gray matter. Each
thalamus rests upon its corresponding crus cerebri, which it embraces. Exter-
nally^ it is bounded by the corpus striatum, and tsenia semicircularis ; and is
continuous with the hemisphere. Internally^ it forms the lateral boundary of
the third ventricle ; and running along its upper border is seen the peduncle of
the pineal gland. Its upper surface is free, being partly seen in the lateral ven-
tricle ; it is partly covered by the fornix, and marked in front by an eminence,
the anterior tubercle. Its under surface forms the roof of the descending cornu
of the lateral ventricle ; into it the crus cerebri passes. Its posterior and inferior
part, which projects into the descending horn of the lateral ventricle, presents
two small rounded eminences, the internal and external geniculate bodies. Its
anterior extremity, which is narrow, forms the posterior boundary of the fora-
men of Monro.
Fiff. 364— The Third and Fourth Ventricles.
The thii'd ventricle is the narrow oblong fissure placed between the thalami
optici, and extending to the base of the brain. It is bounded, above, by the
under surface of the velum interpositum, from which are suspended the choroid
plexuses of the third ventricle ; and, laterally, by two white tracts, one on either
side, the peduncles of the pineal gland. Its floor, somewhat oblique in its direc-
tion, is formed, from before backwards, by the parts which close the interpedun-
cular space, viz., the lamina cinerea, the tuber cinereum and infundibulum, the
630 NERVOUS SYSTEM.
corpora albicantia and tlie locus perforatus posticus; its sides, by tlie optic
tlialami; it is bounded, in front, by the anterior crura of the fornix, and part
of the anterior commissure ; behind, by the posterior commissure, and the iter
a tertio ad quartum ventriculum.
The cavity of the third ventricle is crossed by three commissures, named,
from their position, anterior^ middle^ and posterior.
The anterior commissure is a rounded cord of white fibres, placed in front of
the anterior crura of the fornix. It perforates the corpus striatum on either side,
and spreads out into the substance of the hemispheres, over the roof of the
descending horn of each lateral ventricle.
The middle or soft commissure consists almost entirely of gray matter. It
connects together the thalami optici, and is continuous with the gray matter lining
the anterior part of the third ventricle. It is frequently broken in examining
the brain, and might then be supposed to have been wanting.
The posterior com,missure^ smaller than the anterior, is a flattened white band
of fibres, connecting together the two thalami optici posteriorly. It bounds
the third ventricle posteriorly, and is placed in front of and beneath the pineal
gland, above the opening leading to the fourth ventricle.
The third ventricle has four openings connected with it. In front are the
two oval apertures of the foramen of Monro, one on either side, through which
the third communicates with the lateral ventricles. Behind is a third opening
leading into the fourth ventricle by a canal, the aqueduct of Sylvius, or iter a
tertio ad quartum ventriculum. The fourth, situated in the anterior part of the
floor of the ventricle, is a deep pit, which leads downwards to the funnel-shaped
cavity of the infundibulum {iter ad.infundilmlum).
The lining membrane of the lateral ventricles is continued through the foramen
of Monro into the third ventricle, and extends along the iter a tertio into the
fourth ventricle; at the bottom of the iter ad infundibulum, it ends in a cul-
de-sac.
Or ay matter of tlie third ventricle. A layer of gray matter covers the greater
part of the surface of the third ventricle. In the floor of this cavity it exists
in great abundance, and is prolonged upwards on the sides of the thalami,
extending across the cavity as the soft commissure ; below, it enters into the
corpora albicantia, and surrounds in part the anterior pillars of the fornix.
Behind the third ventricle, and in front of the cerebellum, are the corpora
quadrigemina ; and resting upon these, the pineal gland.
The pineal gland {conarium)^ so named from its peculiar shape (jnnas, a fir-
cone), is a small reddish-gray body, conical in form, placed immediately behind
the posterior commissure, and between the nates, upon which it rests. It is
retained in its position by a duplicature of pia mater, derived from the under
surface of the velum interpositum, Avhich almost completely invests it. The
pineal gland is about four lines in length, and from two to three in width, at
its base, and is said to be larger in the child than in the adult, and in the female
than in the male. Its base is connected with the cerebrum by some transverse
commissural fibres, derived from the posterior commissure; and by four slender
peduncles, formed of medullary fibres. Of these, the two su]^crior pass forwards
upon the upper and inner margin of the oj^tic thalami to the anterior crura of
the fornix, with which they become blended. The inferior peduncles pas's
vertically downwards from the base of the pineal gland, along the back part of
the inner surface of the thalami, and are only seen on a vertical section through
the gland. The pineal gland is very vascular, and consists chiefly of gray matter,
with a few medullaTy fibres. In its base is a small cavity, said by some to
communicate with 1hat of the third ventricle. It contains a transparent viscid
flaid, and occasionally a quantity of sabulous matter, named acervulus cerebri,
com])oscd of phos|)lia1e and carbonate of lime, phosjihatc of magnesia and
ammonia, with a little animal matter. These concretions are almost constant in
CORPORA QUADRIGEMINA. 631
tlieir existence, and are found at all periods of life. "Wlien this body is solid,
the sabulous matter is found upon its surface, and occasionally upon its
peduncles.
On the removal of the pineal gland and adjacent portion of pia mater, the corpora quadrigemina
are exposed.
The corpora or tubercuJa quadriyemina [oj^tic lohes) are four rounded eminences
placed in pairs, two in front, and two behind, and separated from one another
by a crucial depression. They are situated immediately behind the third
ventricle and posterior commissure, beneath the posterior border of the corpus
callosum, and above the iter a tertio ad quartum, ventriculum. The anterior pair,
the nates, are the larger, oblong from before backwards, and of a gray color.
The posterior pair, the testes, are hemispherical in form, and lighter in color
than the preceding. They are connected on each side with the thalamus
opticus, and commencement of the optic tracts, by means of two white promi-
nent bands termed hrachia. Those connecting the nates with the thalamus
(hrachia anteriora) are the larger, and pass obliquely outwards. Those con-
necting the testes with the thalamus, are called the hrachia posteriora. Both
pairs, in the adult, are quite solid, being composed of white matter externally,
and gray matter within. These bodies are larger in the lower animals than in
man. In fishes, reptiles, and birds, they are only two in number, are called
the optic lohes^ from their connection with the optic nerves, and are hollow in
their anterior ; but in mammalia, they are four in number, as in man, and quite
solid. In the human foetus, they are developed at a very early period, and form
a large proportion of the cerebral mass; at first, they are only two in number,
as in the lower mammalia, and hollow in their interior.
These bodies receive, from below, white fibres from the olivary fasciculus or
fillet ; they are also connected with the cerebellum, by means of a large white
cord on each side, the processus ad testes^ or superior peduncles of the cerebellum,
which pass up to the thalami from the tubercula quadrigemina.
The valve of Yieussens is a thin translucent lamina of medullary substance,
stretched between the two processus e cerehello ad testes ; it covers in the canal
leading from the third to the fourth ventricle, forming part of the roof of the
latter cavity. It is narrow in front, where it is connected with the testes ; and
broader behind, at its connection with the vermiform process of the cerebellum.
A slight elevated ridge, the frsenulum, descends upon the upper part of the
valve from the corpora quadrigemina, and on either side of it may be seen the
fibres of origin of the fourth nerve. Its lower half is covered by a thin trans-
versely-grooved lobule of gray matter prolonged from the anterior border of
the cerebellum; this is called by the Italian anatomists the linguetta laminosa.
The corpora geniculcUa are two small flattened, oblong masses, placed on the
outer side of the corpora quadrigemina, and on the u.nder and back part of each
optic thalamus, and named, from tlieir position, corjous geniculatum externum
and internum. They are placed one on the outer and one on the inner side of
each optic tract. In this situation, the optic tract may be seen dividing into
two bands, one of which is connected with the external geniculate body and
nates, the other being connected with the internal geniculate body and testes.
Structure of the cerebrum. The white matter of each hemisphere consists of
three kinds of fibres: 1. Diverging or peduncular fibres, which connect the
hemisphere with the cord and medulla oblongata. 2. Transverse commissural
fibres, which connect together the two hemispheres. 3. Longitudinal commis-
sural fibres, which connect distant parts of the same hemisphere.
The diverging or peduncular fibres consist of a main body, and of certain
accessory fibres. The main body originate in the columns of the cord and
medulla oblongata, and enter the cerebrum through the crus cerebri, where
they are arranged into two bundles, separated by the locus niger. Those fibres
which form the inferior or fasciculated portion of the crus, are derived from
the anterior pyramid, and, ascending, pass mainly through the centre of the
G32 NERVOUS SYSTEM.
striated body; those on the opposite surface of the crus, wliich form the teg-
mentum, are derived from tlie posterior pyramid and fasciculi teretes ; as they
ascend, they pass, some through tlie under part of the tlialamus, and others
through both thalamus and corpus striatum, decussating in these bodies with
each other, and with the fibres of the corpus callosum. The optic thalami also
receive accessory fibres from the j^^^ocessics ad testes^ the olivary fasciculus, the
corpora quadrigemina, and corpora geniculata. Some of the diverging fibres
end in the cerebral ganglia, whilst others pass through and receive additional'
fibres from them, and, as they emerge, radiate into the anterior, middle, and
posterior lobes of the hemisphere, decussating again with the fibres of the corpus
callosum, before passing to the convolutions. These fibres have received the
name of corona racliata.
The transverse commissural jihres connect together the two hemispheres across
the middle line. They are formed by the corpus callosum, and the anterior and
posterior commissu.res.
The longitudinal commissural fibres connect together distant parts of the same
hemisphere, the fibres being disposed in a longitudinal direction. They form
the fornix, the taenia semicircularis, and peduncles of the pineal gland, the
striaa longitudinales, the fibres of the gyrus fornicatus, and the fasciculus nnci-
formis.
The Ceeebellum,
The Cerebellum, or little brain, is that portion of the encephalon which is con-
tained in the inferior occipital fossaa. It is situated beneath the posterior lobes
of the cerebrum, from which it is separated by the tentorium. Its average weight
in the male is 5 ozs. 4 drs. It attains its maximum weight between the twenty-
fifth and fortieth year ; its increase in weight after the fourteenth year being
relatively greater in the female than in the male. The proportion between the
cerebellum and cerebrum is, in the male, as 1 to 8| ; and in the female, as 1 to 8^.
In the infant, the cerebellum is proportionally much smaller than in the adult,
the relation between it and the cerebrum being, according to Chaussier, between
1 to 13, and 1 to 26 ; by Cruveilhier the proportion was found to be 1 to 20. In
form, the cerebellum is oblong, and flattened from above downwards, its greater
diameter being from side to side. It measures from three and a half to four
inches transversely, and from two to two and a half inches from before back-
wards, being about two inches thick in the centre, and about six lines at the
circumference, which is the thinnest part. It consists of gray and white matter :
the former, darker than that of the cerebrum, occupies the surface ; the latter,
the interior. The surface of the cerebellum is not convoluted like the cerebrum,
but traversed by numerous curved furrows or sulci, which vary in depth at
different parts, and separate the laminae of which its exterior is composed.
Its u^rper surface (Fig. 365) is somewhat elevated in the median line, and de-
pressed towards its circumference ; it consists of two lateral hemispheres, con-
nected together by an elevated median portion or lobe, the superior vermiform
process. The median lobe is the fundamental part, and in some anima.ls, as
fishes and reptiles, the only part which exists ; the hemispheres being additions,
and attaining their maximum size in man. The hemispheres arc scjiarated, in
front, by a deep notch, the incisura cerehelli anterior^ which encircles the corpora
quadrigemina behind ; they arc also separated by a similar notch behind, the
incisura, cerehelli -posterior^ in which is received the upper part of the falx cere-
bclli. Tlie superior vermiform process (upper part of the median lobe of the
cerebellum) extends from the notch on the anterior to that on the posterior
border. It is divided into three lobes: the hlndus centralis, a small lobe,
situated in the incisura anterior ; the monticulus cerehelli, the central projecting
part of the process ; and the commissura simplex, a small lobe near the incisura
posterior.
CEREBELLUM.
633
The under surface of tlie cerebellum (Fig. 366) is subdivided into two lateral
hemisplieres by a depression, tbe valley, whicli extends from before_ backwards
in the middle line. The lateral hemispheres are lodged in the inferior occipital
foss£e ; the median depression, or valley, receives the back part of the medulla
Fig. 365.— Upper Surface of tlie Cerebellum.
oblongata, is broader in the centre than at either extremity, and has, projecting
from its floor, part of the median lobe of the cerebellum, called the inferior
vermiform process. The parts entering into the composition of this body are,
from behind forwards, the commissura brevis^ situated in the incisura posterior ;
Fie;. 366.— Under Surface of the Cerebellum.
in front of this, a laminated conical projection, the pyramid; more anteriorly,
a larger eminence, the uvula, which is placed between the two rounded lobes
which occupy the sides of the valley, the amygdalse or tonsils, and is connected
with them by a commissure of gray matter, indented on the surface, called the
furroioed hand. In front of the uvula is the nodule ; it is the anterior pointed
termination of the inferior vermiform process, and projects into the cavity of
the fourth ventricle ; it has been named by Malacarne the laminated tuhercle.
On each side of the nodule is a thin layer, of white substance, attached exter-
nally to the flocculus, and internally to the nodule ; these form together the
posterior m.edullary velum, or commissure of the flocculus. It is usually covered
in and concealed by the amygdalse, and cannot be seen until they are drawn
aside. This band is of a semilunar form on each side, its anterior margin being
634
NERVOUS SYSTEM.
free and concave, its posterior attaclied just in front of tlie furrowed band.
Between it and the nodulus and uvula behind, is a deep fossa, called the svjallow^s
nest (nidus hirundinis).
Lobes of the cerebellum,. Eacli bemispliere is divided into an upper and a lower
portion by tlie great horizontal fissure, which commences in front at the pons,
and passes horizontally round the free margin of either hemisphere, backwards
to the middle line. From this primary fissure numerous secondary fissures pro-
ceed, which separate the cerebellum into lobes.
Upon the upper surface of either hemisphere there are two lobes, separated
from each other by a fissure. These are the anterior or square lobe, which
extends as far back as the posterior edge of the vermiform process, and the
posterior or semilunar lobe, which passes from the termination of the preceding
to the great horizontal fissure.
Upon the under surface of either hemisphere there are five lobes, separated
by sulci ; these are from before backwards. The flocculus or suhpeduncular
lobe, a prominent tuft, situated behind and below the middle peduncle of the
cerebellum ; its surface is composed of gray matter, subdivided into a few small
laminse ; it is sometimes called the p^ieumo gastric lobule, from being situated
behind the pneumogastric nerve. The amyydalse or tonsil is situated on either
side of the great median fissure or valley, and projects into the fourth ventricle.
The digastric lobe is situated on the outside of the tonsil, being connected in
part with the pyramid. Behind the digastric is the slender lobe, which is con-
nected with the back part of the pyramid and the commissura brevis : and more
posteriorly is the inferior posterior lobe, which also joins the commissura brevis
in the valley.
Structure. If a vertical section is made through either hemisphere of the
cerebellum, midway between its centre and the superior vermiform process, the
interior will be found to consist of a central stem of white matter, which con-
tains in its interior a dentate body. From the surface of this central stem a series
of plates of medullary matter are detached, which, covered with gray matter, form
the laminge ; and from the anterior part of each hemisphere arise three large pro-
cesses or peduncles, superior, middle, and inferior, by which the cerebellum is
connected with the rest of the encephalon.
The laminse are about ten or twelve in number, including those on both
surfaces of the cerebellum, those in front being detached at a right angle, and
those behind at an acute
Fi?. 367.— Ycrtical Section of tlie Cerebellum. angle; as each lamina pro-
ceeds outwards, other second-
ary laminas are detached from
it, and from these, tertiary
lamina3. The arrangement
thus described gives to the cut
surface of the organ a foliated
appearance, to which the name
arbor vitse has been given.
Each lamina consists of white
matter, covered externally by
a layer of gray substance.
The white matter of each lam-
ina is derived partly from the
central stem : in addition to
which white fibres pass from
one lamina to another. The
gi'ay matter resembles some-
what the cortical substance
of the convolutions. It consists of two layers : the external one, soft and of a
grayish color ; the internal one, firmer and of a rust color.
FOURTH VENTRICLE. 635
The corpus dentatum, or ganglion of the cerehelhion, is situated a little to tlie
inner side of the centre of the stem of white matter. It consists of an open bag
or capsule of gray matter, the section of which presents a gray dentated outline,
open at its anterior part. It is surrounded by white fibres ; white fibres are also
contained in its interior, which issue from it to join the superior peduncles.
The peduncles of the cerebellum, superior, middle, and inferior, serve to con-
nect it with the rest of the encephalon.
The superior peduncles (^processus e cerehello ad testes) connect the cerebellum
with the cerebrum ; they pass forwards and upwards to the testes, beneath which
they ascend to the crura cerebri and optic thalami, forming part of the diverg-
ing cerebral fibres : each peduncle forms part of the lateral boundary of the
fourth ventricle, and is connected with its fellow of the opposite side by the
valve of Vieussens. The peduncles are continuous behind with the folia of the
inferior vermiform process, and with the white fibres in the interior of the corpus
dentatum. Beneath the corpora quadrigemina, the innermost fibres of each
peduncle decussate with each other, so that some fibres from the right half of
the cerebellum are continued to the left half of the cerebrum.
The inferior peduncles [i^rocessus ad medullam) connect the cerebellum with
the medulla oblongata. They pass downwards, to the back part of the medulla,
and form part of the restiform bodies. Above, the fibres of each process are
connected chiefly with the laminae, on the upper surface of the cerebellum ; and
below, they are connected with all three tracts of one half of the medulla ; and,
through these, with the corresponding half of the cord, excepting the posterior
median columns.
The middle peduncles [processus ad pontem)^ the largest of the three, connect
together the two hemispheres of the cerebellum, forming their great transverse
commissure. They consist of a mass of curved fibres, which arise in the lateral
parts of the cerebellum, and pass across to the same points on the opposite side.
They form the transverse fibres of the pons Varolii.
Fourth Ventricle. (Fig. 364.)
The Fourth Ventricle, or ventricle of the cerebellum, is the space between
the posterior surface of the medulla oblongata and pons in front, and the cere-
bellum behind. It is lozenge-shaped, being contracted above and below, and
broadest across its central part. It is bounded laterally by the processus e cere-
hello ad testes above, and by the diverging posterior pyramids and restiform
bodies below.
The roof is arched ; it is formed by the valve of Vieussens and the under
surface of the cerebellum, which presents, in this situation, four small eminences
or lobules, the nodulus, uvula, and amygdala.
The anterior boundary, or floor, is formed by the posterior surface of the
medulla oblongata and pons. In the median line is seen the posterior median
fissure, which becomes gradually obliterated above, and terminates below in the
point of the calamus scriptorius,- formed by the convergence of the posterior
pyramids. At this point is the orifice of a short canal terminating in a cul-de-
sac, the remains of the canal which extends in foetal life through the centre of
the cord. On each side of the median fissure are two slightly convex longitu-
dinal eminences, the fasciculi teretes: they extend the entire length of the floor,
being indistinct below and of a grayish color, but well marked and whitish
above. Each eminence consists of fibres derived from the lateral tract and resti-
form body, which ascend to the cerebrum. Opposite the crus cerebelli, on the
outer side of the fasciculi teretes, is a small eminence of dark gray substance,
which presents a bluish tint through the thin stratum covering it ; this is called
the locus cseruleus ; and a thin streak of the same color continu.ed up from this on
either side of the fasciculi teretes, as far as the top of the ventricle, is called
the tsenia violacea. The lower part of the floor of the ventricle is crossed by
636 NERVOUS SYSTEM.
several wliite transverse lines, linese transversse ; they emerge from the posterior
median fissure ; some enter the crus cerebelli, others enter the roots of origin
of the auditory nerve, whilst some pass upwards and outwards on the floor of
the ventricle.
The lining membrane of the fourth ventricle is continuous with that of the
third, through the aqueduct of Sylvius, and its cavity communicates below with
the sub-arachnoid space of the brain and cord through an aperture in the layer
of pia mater extending between the cerebellum and medulla oblongata. Later-
ally, this membrane is reflected outwards a short distance between the cerebellum
and medulla.
The choroid plexuses of the fourth ventricle are two in number; they are deli-
cate vascular fringes, which project into the ventricle on each side, passing from
the point of the inferior vermiform process to the outer margin of the restiform
bodies.
The (jray matter in the floor of the ventricle consists of a tolerably thick
stratum, continuous below with the gray commissure of the cord, and extending
up as high as the aqueduct of Sylvius, besides some special deposits connected
with the roots of origin of certain nerves. In the upper half of the ventricle is
a projection situated over the nucleus, from which the sixth and facial nerves
take a common origin. In the lower half are three eminences on each side for
the roots of origin of the eighth and ninth nerves.
For further information on the Descriptive Anatomy of the Nervous Centres, consult: Cru-
veilhier's " Anatomie Descriptive;" Todd's "Descriptive Anatomy of the Brain, Spinal Cord,
and Ganglions ;" Herbert Mayo's " Plates of the Brain and Spinal Cord ;" Arnold's " Tabulae
Anatomicas, Fascic. 1, Icones Cerebri et Mednlte Spinalis ; " Sappey's " Anatomic Descriptive ;"
Tlirschfeld et Leveille's '' Trait§ et Iconographie du Systfeme nerveux ;" and Henle's "Handbuch
der Anatomie."
Cranial Nerves.
The Cranial Nerves, nine in number on eacli side, arise from some part of tbe
cerebro-spinal centre, and are transmitted tlirougli foramina in tlie base of the
cranium. They have been named numerically, according to the order in which
they pass out of the base of the brain. Other names are also given to them
derived from the parts to which they are distributed, or from their functions.
Taken in their order, from before backwards, they are as follows : —
1st. Olfactory. ^..-i j Facial (Portio dura).
2d. Optic. ■ \ Auditory (Portio mollis).
3d. Motor oculi. ( Glosso-pharyngeal. '
4th. Pathetic. 8th. < Pneumogastric (Par vagum). :
5th. Trifacial (Trigeminus). ( Spinal accessory. '
6tli. Abducens. 9th. Hypoglossal. L_
If, however, the 7th pair be considered as two, and the 8th pair as three
distinct nerves, then their number will be increased to twelve, which is the
arrangement adopted by Sommering.
The cranial nerves may be subdivided into four groups, according to the
peculiar function possessed by each, viz., nerves of special sense; nerves of
common sensation ; nerves of motion ; and mixed nerves. These groups may
be thus arranged : —
Nerves of Special Sense. Nerves of Motion.
Olfactory. Motor oculi.
Optic. Pathetic.
Auditory. Part of third division of fifth.
Part of glosso-pharyngeal. Abducens.
Lingual or gustatory branch of fifth. Facial.
Hypoglossal.
Nerves of Common Sensation. Mixed Nerves.
Fifth (greater portion). Pneumogastric.
Part of glosso-pharyngeal. Spinal accessory.
All the cranial nerves are connected to some part of the surface of the brain.
This is termed their superficial or apparent origin. But their fibres may, in all
cases, be traced deeply into the substance of the organ. This part is called their
deep or real origin.
Olfactoet ISTerve. (Fig. 360.)
The First, or Olfactory Nerve, the special nerve of the sense of smell,
may be regarded as a lobe, or portion of the cerebral substance pushed forAvard
in direct relation with the organ to Avhich it is distributed. It arises by three
roots.
The external^ or long root^ is a narrow, white, medullary band, which passes
outwards across the fissure of Sylvius, into the substance of the middle lobe of
the cerebrum. Its deep origin has been traced to the corpus striatum,^ the
superficial fibres of the optic thalamus,^ the anterior commissure,^ and the con-
volutions of the island of Eeil.
' YieusseiiG, Winslow, Monro, Maj'o. ^ Valenlin. ^ Crnveilhier.
i 637 )
638
CRANIAL NERVES.
The middle^ or gray root^ arises from a papilla of gray matter t^caruncula mam-
millaris), imbedded in the anterior lobe. This root is prolonged into the nerve
from the adjacent part of the brain, and contains white fibres in its interior,
which are connected with the corpus striatum.
The internal^ or short root^ is composed of white fibres, which arise from the
inner and back part of the anterior lobe, being connected, according to Foville,
with the longitudinal fibres of the gyrus fornicatus.
These three roots unite, and form a flat band, narrower in the middle than at
either extremity, and of a somewhat prismoid form on section. It is soft in
texture, and contains a considerable amount of gray matter in its substance.
As it passes forwards, it is contained in a deep sulcus, between two convolutions,
lying on the under surface of the anterior lobe, on either side of the longitudinal
fissure, and is retained in position by the arachnoid membrane which covers it.
On reaching the cribriform plate of the ethmoid bone, it expands into an oblong
mass of grayish-white substance, the olfactory bulb. From the under part of
this bulb are given off numerous filaments, about twenty in number, which pass
through the cribriform foramina, and are distributed to the mucous membrane
of the nose. Each filament is surrounded by a tubular prolongation from the
dura mater and pia mater; the former being lost on the periosteum lining the
nose ; the latter, in the neurilemma of the nerve. The filaments, as they enter
the nares, are divisible into three groups : an inner group, larger than those on
the outer wall, spread out over the upper third of the septum ; a middle set,
confined to the roof of the nose ; and an outer set, which are distributed over
the superior and middle turbinated bones, and the surface of the ethmoid in
front of them. As the filaments descend, they unite in a plexiform network,
and become gradually lost in the lining membrane. Their mode of termination
is unknown.
The olfactory differs in structure from other nerves, in containing gray matter
in its interior, and being soft and pulpy in consistence. Its filaments are defi-
cient in the white substance of Schwann, are not divisible into fibrillee, and
resemble the gelatinous fibres, in being nucleated, and of a finelj^-granular tex-
ture.
Fig. 368.— The Optic Nerve and
Optic 'J'ract.
Optic Neeve.
The Second, or Optic Nerve, the special nerve of the sense of sight, is dis-
tributed exclusively to the eyeball. The nerves of opposite sides are connected
together at the commissure; and from the
back of the commissure, they may be traced
to the brain, under the name of the optic
tracts.
The o]Dtic tract^ at its connection with the
brain, is divided into two bands which arise
from the optic thai ami, the corpora geniculata,
and the corpora quadrigemina. The fibres
of origin from the thalamus may be traced
partly from its surface, and partly from its
interior. From this origin, the tract winds
obliquely across the under surface of the crus
cerebri, in the form of a flattened band, desti-
tute of neurilemma, and is attached to the
crus by its anterior margin. It now assumes
a cylindrical form, and, as it passes forwards,
is connected with the tuber cinereum, and
lamina cinerea, from both of which it receives
fibres. According to Foville, it is also con-
ucdcd with tlic ln'iiia stMnicircnlaris, and the
AUDITORY. 639
anterior termination of tlie gyrus fornicatus. It finally joins with, the nerve of
the opposite side, to form the optic commissure.
The commissure or chiasma^ somewhat quadrilateral in form, rests upon the
optic groove of the sphenoid bone, being bounded, in front, by the lamina cinerea ;
behind, by the tuber cinereum ; on either side by the anterior perforated space.
Within the commissure, the optic nerves of the two sides undergo a partial
decussatioD. The fibres which form the inner margin
of each tract are continued across from one to the Fig. 369.— Course of the
other side of the brain, and have no connection with Fibres in the Optic Com-
the optic nerves. These may be regarded as com-
missural fibres (inter-cerebral) between the. thalami
of opposite sides. Some fibres are continued across
the anterior border of the chiasma, and connect the
optic nerves of the two sides, having no relation with,
the optic tracts. They may be regarded as commis- 'W\^ ' **^-i^«/»H»<««fea<to
sural fibres between the two retinae (inter-retinal fibres).
The outer fibres of each tract are continued into the optic nerve of the same side.
The central fibres of each tract are continued into the optic nerve of the oppo-
site side, decussating in the commissure with similar fibres of the opposite
tract.i ^ ^
The optic nerves arise from the fore-part of the commissure, and, diverging
from one another, become rounded in form and firm in texture, and are inclosed
in a sheath derived from the arachnoid. As each nerve passes through the
corresponding optic foramen, it receives a sheath from the dura mater ; and as
it enters the orbit, this sheath subdivides into layers, one of which becomes con-
tinuous with the periosteum of the orbit ; the other forms a sheath for the nerve,
and surrounds it as far as the sclerotic. The nerve passes through the cavity
of the orbit, pierces the sclerotic and choroid coats at the back part of the eyeball,
a little to the nasal side of its centre, and expands into the retina. A small
artery, the arteria centralis retiuc-e, perforates the optic nerve a little behind
the globe, and runs along its interior in a tubular canal of fibrous tissue. It
supplies the inner surface of the retina, and is accompanied by corresponding
Auditory Nerve.
The Auditory Nerve (portio mollis of the seventh pair) is the special nerve
of the sense of hearmg, being distributed exclusively to the internal ear. The
portio dura of the seventh pair, or facial nerve, is the motor nerve of the muscles
of the face. _ It will be described with the cranial motor nerves.
The auditory nerve arises by numerous white stride, the linese transversse,
which emerge from the posterior median fissure in the anterior wall, or floor, of
the fourth ventricle. It is also connected with the gray matter of the medulla,
corresponding to the locus cseruleus. According to Foville, the roots of this
nerve are connected, on the under surface of the middle peduncle, with the gray
-substance of the cerebellum, with the flocculus, and with the gray matter at the
borders of the calamus scriptorius. The nerve winds round the restiform body,
from which it receives fibres, and passes forwards across the posterior border of
the crus cerebelli, in company with the facial nerve, from which it is partially
separated by a small artery. It then enters the meatus auditorius, in company
with the facial nerve, and, at the bottom of the meatus, divides into two branches
cochlear and vestibular, which are distributed, the former to the cochlea, the
latter to the vestibule and semicircular canals. The auditory nerve is very soft
m texture (hence the name, portio mollis), destitute of neurilemma, and, within
the meatus, receives one or two filaments from the facial.
' A specimen of congenital absence of the optic commissure is to be found in the Museum of
the Westminster Hospital.
640
CRANIAL NERVES,
The otlier nerves of special sense must be described with the glosso-pharyn-
geal and fifth nerves, of which thej are parts.
tn^vaXroehh,
Third Nerve. (Figs. 370, 371.)
The Third Nerve {motor oculi) supplies all the muscles of the orbit, except
the Superior oblique and External rectus ; it also sends motor filaments to the
iris. It is a rather large nerve, of rounded form and firm texture, having its
apparent origin from the inner surface of the crus cerebri, immediately in front
of the pons Varolii.
The deep oriyin may be traced into the substance of the crus, where some of
its fibres are connected with the locus niger ; others run downwards, among the
longitudinal fibres of the pons ;
Fig. 370.— Nerves of the Orbit. Seen from above. whilst others ascend, to be con-
nected with the tubercula quad-
rigemina, and valve of Vieussens.
According to Stilling, the fibres
of the nerve pierce the peduncle
and locus niger, and arise from
a gray nucleus in the floor of
the aqueduct of Sylvius. On
emerging from the brain, the
nerve is invested with a sheath
of pia mater, and inclosed in a
prolongation from the arachnoid.
It then pierces the dura mater
on the outer side of the anterior
clinoid process, where its serous^
covering is reflected from it, and
it passes along the outer wall of
the cavernous sinus, above the
other orbital nerves, receiving
in its course one or two filaments
from the cavernous plexus of
the sympathetic. It then di-
vides into two branches, which
enter the orbit through tlie
sphenoidal fissure, between the
two heads of the External rec-
tus muscle. On passing through
the fissure, the nerve is placed
below the fourth, and the frontal
and lachrymal branches of the
ophthalmic nerve.
The superior divisioji, .the
smaller, passes inwards across the optic nerve, and supplies the Superior rectus
and Levator palpebroe.
The inferior division, the larger, divides into three branches. One passes
beneath the optic nerve to the Internal rectus ; anotlicr to the Inferior rectus ;
and the third, the largest of the three, passes forwards between the Inferior and
External recti, to the Inferior oblique. From the latter, a short thick branch
is given off' to the lower part of the lenticular ganglion, forming its inferior
root, as well as two filaments to the inferior rectus. All Ihcsc branches enter
the muscles on llieir ocular surface.
Hfeirrrrnf Filajitriit
tiiMura-Matar
FOURTH— SIXTH.
641
Fourth Nerve. (Fig. 370.)
The Fourth Nerve (trochlear), the smallest of the cranial nerves, supplies
the Superior oblique muscle. It arises from the upper part of the valve of
Yieussens, immediately behind the testis, and divides beneath the corpora
quadrigemina, into two fasciculi ; the anterior one arising from a nucleus of
gray matter, close to the middle line of the floor of the Sylvian aqueduct ; the
posterior one from a gray nucleus, at the upper part of the floor of the fourth
ventricle, close to the origin of the fifth nerve. The two nerves are connected
together at their origin, by a transverse band of white fibres, which crosses the
surface of the valve of Vieussens. The nerve winds round the outer side of
the crus cerebri, immediately above the pons Varolii, pierces the dura mater in
the free border of the tentorium cerebelli, near the posterior clinoid process,
above the oval opening for the fifth nerve, and passes forwards through the
outer wall of the cavernous sinus, below the third ; but, as it enters the orbit,
through the sphenoidal fissure, it becomes the highest of all the nerves. In the
orbit, it passes inwards, above the origin of the Levator palpebree, and finally
enters the orbital surface of the Superior oblique muscle.
Fig. 371. — Nerves of tbe Orbit and Ophthalmic Gaugliou. Side View.
& CairoUd
In the outer wall of the cavernous sinus, this nerve receives some filaments
from the carotid plexus of the sympathetic. It is not unfrequently blended
with the ophthalmic division of the fifth ; and occasionally gives ofi' a branch
to assist in the formation of the lachrymal nerve. It also gives off a recurrent
branch, which passes backwards between the layers of the tentorium, dividing
into two or three filaments, which may be traced as far back as the wall of the
lateral sinus.
Sixth Nerve.
The Sixth Nerve {ahducens) supplies the External rectus muscle. Its appa-
rent origin is by several filaments from the constricted part of the corpus pyra-
midale, close to the pons, or from the lower border of the pons itself.
The deep origin of this nerve has been traced, by Mayo, between the fasciculi
of the corpus pyramidale, to the posterior part of the medulla, where Stilling
has shown its connection with a e'ray nucleus in the floor of the fourth ventricle.
41
642 CRANIAL NERVES.
Tlie nerve pierces tlie dura mater, immediately below the posterior clinoid pro-
cess, lying in a groove bj the side of the body of the sphenoid bone. It passes
forwards through the cavernous sinus, lying on the outer side of tbe internal
carotid artery, where it is joined by several -filaments from the carotid plexus,
by one from Meckel's ganglion (Bock), and another from the ophthalmic nerve.
It enters the orbit through the sphenoidal fissure, and lies above the ophthalmic
vein, from which it is separated by a lamina of dura mater. It then passes
between the two heads of the External rectus, and is distributed to that muscle
on its ocular surface.
The above-mentioned nerves, as well as the ophthalmic division of tlie fifth
as they pass to the orbit, bear a certain relation to each other in the cavernous
sinus, at the sphenoidal fissure, and in the cavity of the orbit, which will be now
described.
In the cavernous sinus, the third, fourth, and ophthalmic division of the fifth,
are placed in the dura mater of the outer wall of the sinus, in their numerical
order, both from above downwards, and from within outwards. The sixtli
nerve lies at the outer side of the internal carotid artery. As these nerves
pass forwards to the sphenoidal fissure, the third and fifth nerves become
divided into branches, and the sixth approaches the rest; so that their relative
position becomes considerably changed.
In the sphenoidal fissure, th.e fourth, and the frontal and lachrymal divisions
of the ophthalmic, lie upon the same plane, the former being most internal, the
latter external ; and they enter the cavity of the orbit above the muscles. The
remaining nerves enter the orbit between the two heads of the External rectus.
The superior division of the third is the highest of these ; beneath, this lies the
nasal branch of the fifth ; then the inferior division of the third ; and the sixth
lowest of all.
In the orbit, the fourth, and the frontal and lachrymal divisions of the oph-
thalmic, lie on the same plane immediately beneath the periosteum, the fourth"
nerve being internal and resting on the Superior oblique, the frontal resting on
the Levator palpebriB, and the lachrymal on the external rectus. Next in order
comes the superior division of the third nerve lying immediately beneath the
Superior rectus, and then the nasal division of the fifth crossing the optic nerve
from the onter to the inner side of the orbit. Beneath these is found the optic
nerve, surrounded in front by the ciliary nerves, and having the lenticular
ganglion on its outer side, between it and the External rectus. Below the
optic is the inferior division of the tliird, and the sixth, which lies on the outer
side of the orbit.
Facial ISTepive.
The Facial Nerve [portio dwa of the seventh pair) is the motor nerve of
all the muscles of expression in the face, and of the Pkitysma and Buccinator.
It supplies also two of the muscles of the external ear, the posterior belly of the
Digastric, and the Stylo-hyoid. Througli the chorda tympani it supplies the
Lingualis ; by its tympanic
Fig. 372.— The Cowrse and Connection of the Facial branch, the Stapedius and Laxa-
Nerve, in the Temporal Bone. ^^^ tympani ; through the otic
|V]«-v — JS ganglion, the Tensor tjnnpani;
E.tcr.ai Frfrcsai \h^N //L^>^^,rn'/'Mi\ ^^^^ through thc connection of
"tS"^"'!^/^:^^^^^^^^^^ " * \ ^^« tvnwV with, the Vidian nerve,
, ^ ,., l'\~WE^^W\h^ M bv the petrosal nerve, it probably
Jntumescen/iii Gannliformm 1 IB" !!l'i[iW* a a^ \ \ T i T t • i
Wiiif^yT^vfe \ '^k i^'ipp'^^'^ "^^^ Levator palati and
« -• ; racJ^^^K^' '." ^^Sl'f .'A 1 A/ygos uvnlas. It arises from
'■■^-WdZry ''''''*%LjM I 1h(> lateral tract of the medulla
^"'^-'^ ' (iblongatii, in the groove between
tlic olivarv and rcstitbrm bodies.
FACIAL. 643
Its deep origin may be traced to the floor of tlie fourth ventricle, where it is
connected with the same nucleus as the sixth nerve. This nerve is situated a
little nearer to the middle line than the portio mollis, close to the lower border
of the pons Varolii, from which some of its fibres are derived.
Connected with this nerve, and lying between it and the portio mollis, is a
small fasciculus [portio inter duram et moUein of Wrisberg, or portio intermedia).
This accessory portion arises from the lateral column of the cord.
The nerve passes forwards and outwards upon the crus cerebelli, and enters
the internal auditory meatus with the auditory nerve. Within the meatus, the
facial nerve lies first to the inner side of the auditory, and then in a groove
upon that nerve, and is connected to it by one or two filaments.
At the bottom of the meatus, it enters the aqu^eductus Fallopii, and follows
the serpentine course of that canal through the petrous portion of the temporal
bone, from its commencement at the internal meatus to its termination at the
stylo-mastoid foramen. It is at first directed outwards towards the hiatus
Fallopii, Avhere it forms a reddish gangiiform swelling (intumescentia ganglio-
formisj, and is joined by several nerves; then bending suddenly backwards, it
runs in the internal wall of the tympanum, above the fenestra ovalis, and at
the back of that cavity passes vertically downwards to the stylo-mastoid
foramen.
On emerging from this aperture, it runs forwards in the substance of the
parotid gland, crosses the external carotid artery, and divides behind the ramus
of the lower jaw into two primary branches, temporo- facial and cervico-facial,
from which numerous offsets are distributed over the side of the head, face, and
upper part of the neck, supplying the superficial muscles in these regions. As
the primary branches and their offsets diverge from each other, they present
somewhat the appearance of a bird's claws ; hence the name of pes anserinus is
given to the divisions of the facial nerve in and near the parotid gland.
The communications of the facial nerve may be thus arranged : —
In the internal auditory meatus . With the auditory nerve.
With Meckel's ganglion by the large
petrosal nerve.
With the otic ganglion by the small
In the aquEeductus Fallopii . \ petrosal nerve.
With the sympathetic on the middle
meningeal by the external petrosal
nerve.
With the pneumogastric.
" glosso-pharyngeal.
At its exit from the stylo-mastoid -! " carotid plexus,
foramen ..... " auricularis magnus.
[ " auriculo-temporal.
On the face .... With the three divisions of the fifth.
In the internal auditory meatus, some minute filaments pass between the facial
and auditory nerves.
Opposite the hiatus Fallopii, the ganglioform enlargement on the facial nerve
communicates by means of the large petrosal nerve, with Meckel's ganghon,
forming its motor root ; by a filament from the small petrosal, with the otic
ganghon; and by the external petrosal, with the sympathetic filaments accom-
panying the middle meningeal artery (Bidder). From the ganglioform enlarge-
ment, according to Arnold, a twig is sent back to the auditory nerve.
At its exit from the stylo-mastoid foramen, it sends a twig to the pneumo-
gastric, another to the glosso-pharyngeal nerve, and communicates with the
carotid plexus of the sympathetic, with the great auricular branch of the cervical
plexus, with the auriculo-temporal branch of the inferior maxillary nerve in
the parotid gland, and on the face with the terminal branches of the three
divisions of the fifth.
QU
CRANIAL NERVES,
Branches of Distribution.
Within aqueednctnsFallopii | cStympani.
. ^ .^ o ^ ^ X -J ( Posterior auricular.
At exit irom styio-mastoid ) t^- . •
^^^^^^^ .... I stllo-hyoid.
{Temporal.
Malar,
Infraorbital.
' ( Jiuccal.
^ Cervico-facial } Supramaxillarj.
( Inframaxillary.
Tlie Ty^njjanic branch arises from the nerve opposite the pyramid; it is
small filament, which supplies the Stapedius and Laxator tympani muscles.
Fig. 373. — The Nerves of the Scalp, Face, and side of the Neck.
of Supra - tj-ocJilear
of Infra-irochleaT
of Nasal
The niordn. lywpani is ^Wv.n off from the facial as it passes vertically down-
wards at the back of the tympanum, about a quarter of an mch before its exit
BRANCHES OF DISTRIBUTION. 645
from the stylo-mastoid foramen. It ascends from below upwards in a distinct
canal, parallel with the aqugeductus Fallopii, and enters the cavity of the tym-
panum through an opening (iter chord* posterius) between the base of the
pyramid and the attachment of the membrana tympani, and becomes invested
with mucous membrane. It passes forwards through the cavity of the tvm-
panum, between the handle of the malleus and vertical ramus of the incus, to its
anterior inferior angle, and emerges from that cavity through a foramen at the
inner side of the Glaserian fissure which is called the iter chord^B anterius, or canal
of Huguier. It then descends between the two Pterygoid muscles, and meets
the gustatory nerve at an acute angle, after communicating with which, it
accompanies it to the submaxillary gland ; it then joins the submaxillary gan-
glion, from whence it has been traced by some anatomists into the proper
muscular fibres of the tongue — the Lingualis muscle.
The Posterior auricular nerve arises close to the stylo-mastoid foramen, and
passes upwards in front of the mastoid process, where it is joined by a filament
from the auricular branch of the pneumogastric, and communicates with the
deep branch of the auricular magnus ; as it ascends between the meatus and
mastoid process it divides into two branches. The auricular branch supplies the
Retrahens aurem. The occipital branchy the larger, passes backwards along the
superior curved line of the occipital bone, and supplies the occipital portion of
the Occipito-frontalis.
The Stylo-hyoid is a long slender branch, which passes inwards, entering the
Stylo-hyoid muscle about its middle; it communicates with the sympathetic
filaments on the external carotid artery.
The Digastric branch usually arises by a common trunk with the preceding;
it divides into several filaments, which supply the posterior belly of the Digas-
tric; one of these perforates that muscle to join the glosso-pharyngeal nerve.
The Temporo-facial^ the larger of the two terminal branches, passes upwards
and forwards through the parotid gland, crosses the neck of the condyle of the
jaw, being connected in this situation with the auriculo-temporal branch of the
inferior maxillary nerve, and divides into branches, which are distributed over
the temple and upper part of the face ; these are divided into three sets, temporal,
malar, and infraorbital.
The temporal branches cross the zygoma to the temporal region, supplying
the Attrahens aurem muscle, and join with the temporal branch of the superior
maxillary, and with the auriculo-temporal branch of the inferior maxillary.
The more anterior branches supply the frontal portion of the Occipito-frontalis,
and the Orbicularis palpebrarum muscle, joining with the supraorbital branch
of the ophthalmic.
The malar branches pass across the malar bone to the outer angle of the orbit,
where they supply the Orbicularis and Corrugator supercilii muscles, joining
with filaments from the lachrymal and supraorbital nerves: others supply the
lower eyelid, joining with filaments of the malar branches of the superior
maxillary nerve.
The infraorbital^ of larger size than the rest, pass horizontally forwards to be
distributed between the lower margin of the orbit and the mouth. The superfi-
cial branches run beneath the skin and above the superficial muscles of the face,
which they supply; some supply the lower eyelid and Pyramidalis nasi, joining
at the inner angle of the orbit with the infratrochlear and nasal branches of the
ophthalmic. The deep branches pass beneath the Levator labii superioris, supply
it and the Levator anguli oris, and form a plexus (infraorbital) by joining with
the infraorbital branch of the superior maxillary nerve.
The Cervico-facial division of the facial nerve passes obliquely downwards and
forwards through the parotid gland, where it is joined by branches from the
great auricular nerve; opposite the angle of the lower jaw it divides into
branches which are distributed on the lower half of the face and upper part of
646
CRANIAL NERVES,
the neck. These may be divided into tliree sets: buccal, supramaxillary, and
inframaxillary.
The huccal branches cross the Masseter muscle. They supply the Buccinator
and Orbicularis oris, and join with the infraorbital branches of the temporo-
facial division of the nerve, and with filaments of the bnccal branch of the infe-
rior maxillary nerve.
The supramaxillary brandies pass forwards beneath the Platysma and Depres-
sor anguli oris, supplying the muscles of the lip and chin, and anastomosing
Avith the mental branch of the inferior dental nerve.
The inframaxillary branches run forward beneath the Platysma, and form a
series of arches across the side of the neck over the supra-hyoid region. One
of these branches descends vertically to join with the superficial cervical nerve
from the cervical plexus; others supplj^ the Platysma.
Ninth, or Hypoglossal Nerve.
The Ninth Nerve [hypoglossal) is the motor nerve of the tongne. It arises
by several filaments, from ten to fifteen in number, from the groove between the
Fig. 374. — Hypoglossal Nerve, Cervical Plexus, and their branches.
pyramidal and olivjjry l)odics, in a conlinnous line with the anterior roots of
the spinal nerves. According to Stilhng, these roots may be traced to a gray
nucleus in the floor of 1he medulla oblongata, between the posterior median
furrow and the nuclei (jf ihe glosso-pharyngeal and vagus nerves. The filaments
FIFTH NERVE. 647
of tliis nerve are collected into two bundles, wliicli perforate tbe dura mater
separately, opposite tlie anterior condyloid foramen, and unite together after
their passage through it. In those cases in which the anterior condyloid fora-
men in the occipital bone is double, these two portions of the nerve are sepa-
rated by a small piece of bone, which divides the foramen. The nerve descends
almost vertically to a point corresponding with the angle of the jaw. It is at
first deeply seated beneath the internal carotid and internal jugular vein, and
intimately connected with the pneumogastric nerve; it then passes forwards
between the vein and artery, and at a lower part of the neck becomes superficial
below the Digastric muscle. The nerve then loops round the occipital artery,
and crosses the external carotid below the tendon of the Digastric muscle. It
passes beneath the Mylo-hyoid muscle, lying between it and the Hyo-glossus,
and is connected at the anterior border of the latter muscle with the gu.statory
nerve ; it is then continued forwards into the Genio-hyo-glossus muscle as far as
the tip of the tongue, distributing branches to its substance.
Branches of this nerve communicate with the
Pneumogastric. First and second cervical nerves.
Sympathetic. Gustatory.
The communication with the pneumogastric takes place close to the exit of
the nerve from the skull, numerous filaments passing between the hj-poglossal
and second ganglion of the pneumogastric, or both being united so as to form
one mass.
The communication with the sympathetic takes place opposite the atlas, by
branches derived from the superior cervical ganglion, and in the same situation
the ninth is joined by a filament derived from the loop connecting the first two
cervical nerves.
The communication with the gustatory takes place near the anterior border
of the Hyo-glossus muscle by numerous filaments which ascend upon it.
The branches of distribution are the
Descendens noni. Thyro-hyoid.
Muscular,
The descendens noni is a long slender branch, which quits the hypoglossal
where it turns round the occipital artery. It descends obliquely across the
sheath of the carotid vessels, and joins just below the middle of the neck, to
form a loop with the communicating branches from, the second and third cervical
nerves. From the convexity of this loop branches pass forwards to supply the
Sterno-hyoid, Sterno-thyroid, and both bellies of the Omo-hyoid. According to
Arnold, another filament desends in front of the vessels into the chest, which
joins the cardiac and phrenic nerves. The descendens noni is occasionally con-
tained in the sheath of the carotid vessels, being sometimes placed over and
sometimes beneath the internal jugular vein.
The thyro-hyoid is a small branch, arising from the hypoglossal near the pos-
terior border of the Hyo-glossus ; it passes obliquely across the great cornu of
the hyoid bone, and supplies the Thyro-hyoid muscle.
The muscular branches are distributed to the Stylo-glossus, Hyo-glossus, Genio-
hyoid, and Genio-hyo-glossus muscles. At the under surface of the tongue,
numerous slender branches pass upwards into the substance of the organ.
Fifth ISTeeve.
The Fifth ISTerve (trifacial^ trigeminus) is the largest cranial nerve, and
resembles a spinal nerve, in its origin by two roots, and in the existence of a
ganglion on its posterior root. The functions of this nerve are various. It is
a nerve of special sense, of common sensation, and of motion. It is the great
sensitive nerve of the cranium and face, the motor nerve of the muscles of
648 CRANIAL NERVES.
mastication, and its lingual brancli is one of tlie nerves of tlie special sense of
taste. It arises by two roots, a posterior larger or sensory, and an anterior
smaller or motor root. Its superficial origin is from tlie side of tlie pons Varolii,
a little nearer to tlie upper tlian the lower border. The smaller root consists
of three or four bundles ; in the larger, the bundles are more numerons, varying
in number from seventy to a hundred : the two roots are separated from one
another by a few of the transverse fibres of the pons. The deep origin of the
larger or sensory root may be traced between the transverse fibres of the pons
Varolii to the lateral tract of the medulla oblongata, immediately behind the
olivary body. According to some anatomists, it is connected with the gray
nucleus at the back part of the medulla, between the fasciculi teretes and resti-
form columns. By others, it is said to be continuous with the fasciculi teretes
and lateral column of the cord ; and, according to Foville, some of its fibres are
connected with the transverse fibres of the pons; whilst others enter the cere-
bellum, spreading out on the surface of its middle peduncle. The motor root
has been traced by Bell and Eetzius to be connected with the pyramidal body.
The two roots of the nerve pass forwards through an oval opening in the dura
mater, opposite the internal auditory meatus : here the fibres of the larger root
enter a large semilunar ganglion (Casserian), while the smaller root passes
beneath the ganglion without having any connection with it, and joins outside
the cranium with one of the trunks derived from it.
The Casserian, or Semilunar Ganglion, is lodged in a depression near the
apex of the petrous portion of the temporal bone. It is of a somewhat cres-
centic form, with its convexity turned forwards. Its upper surface is intimately
adherent to the dura mater. Besides the small or motor root, the large super-
ficial petrosal nerve lies underneath the ganglion.
Branches. This ganglion receives, on its inner side^ filaments from the carotid
plexus of the sympathetic; and from it some minute branches are given off to
the tentorium cerebelli, and the dura mater, in the middle fossa of the cranium.
From its anterior harder^ which is directed forwards and outwards, three large
branches proceed: the ophthalmic, superior maxillary, and inferior maxillary.
The ophthalmic and superior maxillary consist exclusively of fibres derived
from the larger root and ganglion, and are solely nerves of common sensation.
The third division, or inferior maxillary, is composed of fibres from both roots.
This, therefore, strictly speaking, is the only portion of the fifth nerve which
can be said to resemble a spinal nerve.
Ophthalmic Nerve, (Fig. 370.)
The Ophthalmic, or first division of the fifth, is a sensory nerve. It supplies
the eyeball, the lachrymal gland, the mucous lining of the eye and nose, and
the integument and muscles of the eyebrow and forehead. It is the smallest
of the three divisions of the fifth, arising from the upper part of the Casserian
ganglion. It is a short, flattened band, about an inch in length, which passes
forwards along the outer wall of the cavernous sinus, below the other nerves,
and just before entering the orbit, through the sphenoidal fissure, divides into
three branches, lachrymal, frontal, and nasal. The ophthalmic nerve is joined
by filaments from the cavernous plexus of the sympathetic, and gives off
recurrent filaments which pass between the layers of the tentorium, with a
brancli from the fourth nerve.
Its branches are, the
Tjnchrymal. Frontal. Nasal.
The LarJirjirndl is the smallest of iho three branches of the ophthalmic. Not
unfrcqucntly it nriscs by two filnmonts, one from the o])hthalniic, the other from
the fourth, nnd lhis Swan considers to be its usual coiulilion. It ])asses forAvards
in a separate tube of dura mater, and enters tlic orbit through the narrowest
OPHTHALMIC. 649
part of tlie splienoidal fissure. In tlie orbit, it runs along the npper border of
the External rectus muscle, with the lachrymal artery, and is connected with
the orbital branch of the superior maxillary nerve. Within the lachrymal
gland it gives off several filaments, which supply the gland and the conjunctiva.
Finally, it pierces the palpebral ligaments, and terminates in the integument
of the upper eyelid, joining with filaments of the facial nerve.
The Frontal is the largest division of the ophthalmic, and may be regarded,
both from its size and direction, as the continuation of this nerve. It enters
the orbit above the muscles, through the highest and broadest part of the
sphenoidal fissure, and runs forwards along the middle line, between the Levator
palpebrse and the periosteum. Midway between the apex and base of the orbit
it divides into two branches, supratrochlear and supraorbital.
The suj^ratrochlear branchy the smaller of the two, passes inwards, above the
pulley of the Superior oblique muscle, and gives off" a descending filament, which
joins with the infratrochlear branch of the nasal nerve. It then escapes from
the orbit between the pulley of the Superior oblique and the supraorbital
foramen, curves up on to the forehead close to the bone, and ascends behind
the Corrugator supercilii and Occipito-frontalis muscles, to both of which it is
distributed ; finally, it is lost in the integument of the forehead.
The supraorbital branch passes forwards through the supraorbital foramen,
and gives off, in this situation, palpebral filaments to the upper eyelid. It then
ascends upon the forehead, and terminates in muscular, cutaneous, and peri-
cranial branches. The muscular branches supply the Corrugator supercilii,
Occipito-frontalis, and Orbicularis palpebrarum, furnishing these muscles with
common sensation, and joining in the substance of the latter muscle with the
facial nerve. The cutaneous branches^ two in number, an inner and an outer,
supply the integument of the cranium as far back as the occiput. They are at
first situated beneath the Occipito-frontalis, the inner branch perforating the
frontal portion of the muscle, the outer branch its tendinous aponeurosis. The
pericranial branches are distributed to the pericranium over the frontal and
parietal bones. They are derived from the cutaneous branches whilst beneath
the muscle.
The Nasal nerve is intermediate in size between the frontal and lachrymal,
and more deeply placed than the other branches of the ophthalmic. It enters
the orbit between the two heads of the External rectus, and passes obliquely
inwards across the optic nerve, beneath the Levator palpebrse and superior
rectus muscles, to the inner wall of the orbit, where it enters the anterior
ethmoidal foramen, immediately below the superior oblique. It then enters
the cavity of the cranium, traverses a shallow groove on the front of the
cribriform plate of the ethmoid bone, and passes down, through the slit by the
side of the crista galli, into the nose, where it divides into two branches, an
internal and an external. The internal branch supplies the mucous membrane
near the fore part of the septum of the nose. The external branch descends in
a groove on the inner surface of the nasal bone, and supplies a few filaments to
the mucous membrane covering the fore part of the outer wall of the nares as
far as the inferior spongy bone ; it then leaves the cavity of the nose, between
the lower border of the nasal bone and the upper lateral cartilage of the nose,
and, passing down beneath the compressor nasi, supplies the integument of the
ala and the tip of the nose, joining with the facial nerve.
The branches of the nasal nerve are, the ganglionic, ciliary, and infratrochlear.
The ganglionic is a long, slender branch, about half an inch in length, which
usually arises from the nasal, between the two heads of the external rectus. It
passes forwards on the outer side of the optic nerve, and enters the superior and
posterior angle of the ciliary ganglion, forming its superior, or long root. It is
sometimes joined by a filament from the cavernous plexus of the sympathetic,
or from the superior division of the third nerve.
The long ciliary nerves two or three in number, are given off" from the nasal
650 CRANIAL NERVES.
as it crosses the optic nerve. They join the short ciliary nerves from the ciliary
ganglion, pierce the posterior part of the sclerotic, and, running forwards between
it and the choroid, are distributed to the ciliary muscle and iris.
The infratrochleaf hranch is given oW just as the nasal nerve passes through
the anterior ethmoidal foramen. It runs forwards along the upper border of
the Internal rectus, and is joined, beneath the pulley of the Superior oblique,
by a filament from the supratrochlear nerve. It then passes to the inner angle
of the eye, and supplies the Orbicularis palpebrarum, the integument of the
eyelids, and side of the nose, the conjunctiva, lachrymal sac, and caruncula
lachrymalis.
Connected with the three divisions of the fifth nerve are four small ganglia,
which form the whole of the cephalic portion of the sympathetic. With the
first division is connected the ophthalmic ganglion; with the second division,
the spheno-palatine, or Meckel's ganglion ; and with the third, the otic and
submaxillary ganglia. All the four receive sensitive filaments from the fifth,
and motor and sympathetic filaments from various sources ; these filaments are
called the roots of the ganglia. The ganglia are also connected with each other,
and with the cervical portion of the sympathetic.
Ophthalmic Gaistgliox. (Fig. 371.)
The Ophthalmic, Lenticular, or Ciliary Ganglion, is a small, quadrangular
flattened ganglion, of a reddish-gray color, and about the size of a pin's head,
situated at the back part of the orbit between the optic nerve and the External
rectus muscle, lying generally on the outer side of the ophthalmic artery. It is
inclosed in a quantity of loose fat, which makes its dissection somewhat difficult.
Its tranches of communication^ or roots^ are three, all of which enter its pos-
terior border. One, the long root, is derived from the nasal branch of the oph-
thalmic, and joins its superior angle. The second, the short root, is a short thick
nervCj. occasionally divided into two parts, which is derived from the branch of
the third nerve to the Inferior oblique muscle, and is connected with the inferior
angle of the ganglion. The third, the sympathetic root, is a slender filament
from the cavernous plexus of the sympathetic. This is occasionally blended
with the long root, and sometimes passes to the ganglion separately. According
to Tiedemann, this ganglion receives a filament of communication from the
spheno-palatine ganglion.
Its tranches of distritution are the short ciliary nerves. These are delicate
filaments from ten to twelve in number, which arise from the fore part of the
ganglion in two bundles, connected with its superior and inferior angles ; the
upper handle consisting of four filaments, and the lower of six or seven. They
run forwards with the ciliary arteries in a wavy course, one set above and the
other below the optic nerve, pierce the sclerotic at the back part of the globe,
pass forwards in delicate grooves on its inner surface, and are distributed to the
ciliary muscle and iris. A small filament is described by Tiedemann, penetrating
the optic nerve with the arteria centralis retinaj.
SuPEKiOR Maxillary Nerve. (Fig. 375.)
The Superior Maxillary, or second division of the fifth, is a sensory nerve. It
is intermediate, both in position and size, between the ophthalmic and inferior
maxillary. It commences at the middle of the Casserian ganglion as a flattened
plcxiform band, and passes forwards through the foramen rotundum, where it
becomes more cylindrical in form, and firmer in texture. It then crosses the
sphcno-maxillary fossa, traverses the infraorbital canal in the floor of the orbit,
and appears upon tlic face at the infraorbital foramen. At its termination, the
nerve lies beneath the Levator labii superioris muscle, and divides into a leasli
SUPERIOR MAXILLARY.
651
of branches, wliicli spread out upon tlie side of the nose, the lower eyelid, and
upper lip, joining with filaments of the facial nerve.
The branches of this nerve may be divided into three groups: 1. Those given
off in the spheno-maxillary fossa. 2.. Those in the infraorbital canal. 3. Those
on the face.
( Orbital.
Spheno-maxillary fossa -x Spheno-palatine.
( Posterior dental.
Infraorbital canal . . Anterior dental.
{Palpebral.
jSTasal.
Labial.
The Orbital branch arises in the spheno-maxillary fossa, enters the orbit by
the spheno- maxillary fissure, and divides at the back of that cavity into two
branches, temporal and malar.
Fig. 375. — Distribution of the Second and Third Divisions of the Fifth Nerve
and Submaxillary Ganglion.
'^.-jianvr Hooi
^o'ibT Jipo-t
JuiTteuIo -Ternp
The te'mporal branch runs in a groove along the outer wall of the orbit (in the
malar bone), receives a branch of communication from the lachrymal, and, pass-
ing through a foramen in the malar bone, enters the temporal fossa. It ascends
between the bone and substance of the Temporal muscle, pierces this muscle and
the temporal fascia about an inch above the zygoma, and is distributed to the
integument covering the temple and side of the forehead, communicating with
the facial and auriculo-temporal branch of the inferior maxillary nerve.
The raalar branch passes along the external inferior angle of the orbit, emerges
652 CRANIAL NERVES.
upon tlie face tlirongli a foramen in tlie malar bone, and perforating tlie Orbicu-
laris palpebrarum muscle on the prominence of the cheek, joins with the facial.
The s2:)heno-palatine branches^ two in number, descend to the spheno-palatine
ganglion.
^]iQ posterior dental hranclies arise from the trunk of the nerve just as it is
about to enter the infraorbital canal ; thej are two in number, posterior and
anterior.
The posterior hranch passes from behind forwards in the substance of the supe-
rior maxillary bone, and joins opposite the canine fossa with the anterior dental.
Numerous filaments are given off from the lower border of this nerve, which
form a minute plexus in the outer wall of the superior maxillary bone, imme-
diately above the alveoli. From this plexus filaments are distributed to the
pulps of the molar and second bicuspid teeth, the lining membrane of' the
antrum, and corresponding portion of the gums.
The anterior hranch is distributed to the gums and Buccinator muscle.
The anterior dental^ of large size, is given off from the su.perior maxillary
nerve just before its exit from the infraorbital foramen ; it enters a special canal
in the anterior wall of the antrum, and anastomoses with the posterior dental.
From this nerve some filaments are distributed to the incisor, canine, and first
bicuspid teeth ; others are lost upon the lining membrane covering the fore part
of the inferior meatus. In this situation it forms a communication with a nasal
branch from Meckel's ganglion called the ganglion of Bochdalek.
I^YiQ IDalpehralhranches pass upwards beneath the Orbicularis palpebrarum.
They supply this muscle, the integument, and conjunctiva of the lower eyelid
with sensation, joining at the outer angle of the orbit with the facial nerve and
malar branch of the orbital.
The nasal branches pass inwards ; they supply the muscles and integument of
the side of the nose, and join Avith the nasal branch of the ophthalmic.
The labial branches^ the largest and most numerous, descend beneath the
Levator labii superioris, and are distributed to the integument and muscles of
the upper lip, the mucous membrane of the mouth, and labial glands.
All these branches are joined, immediately beneath the orbit, by filaments
from the facial nerve, forming an intricate plexus, the infraorbital.
Spheno-palatine Ganglion. (Fig. 376.)
The Spheno-palatine Ganglion (Meckel's), the largest of the cranial ganglia, is
deeply placed in the spheno-maxillary fossa, close to the spheno-palatine fora-
men. It is triangular or heart-shaped, of a reddish-gray color, and placed
mainly behind the palatine branches of the superior maxillary nerve, at the
point where the sympathetic root joins the ganglion. It consequently does not
involve those nerves which pass to the palate and nose. Like the other gan-
glia of the fifth nerve, it possesses a motor, a sensory, and a sympathetic root.
Its motor root is derived from the facial, through the Vidian ; its sensory root
from the fifth; and its sympathetic root from the carotid plexus, through the
Vidian. Its branches are divisible into four groups: ascending, which pass to
the orbit; descending, to the palate; internal, to the nose; and posterior
branches, to the pharynx.
The ascendincj brandies are two or three delicate filaments, which enter the
orbit by the spheno-maxillary fissure, and supply the periosteum. Arnold
describes and delineates these iDranchcs as ascending to the optic nerve ; one, to
the sixth nerve (Bock); and one to the ophthalmic ganglion (Tiedemann).
The descending ot pala.tine branches are distributed to the roof of the mouth,
the soft palate, tonsil, and lining membrane oP tlie nose. They are almost a
direct continuation of the spheno-palatine l)ranchcs of the superior niaxillary
nerve, and arc three in number: anterior, middle, and ])ostcrior.
The antcj'ior, oj- lai'ge palatine nerve, descends through the posterior ]-)alatinc
SPHENO-PALATINE GANGLION.
653
canal, emerges upon the liard palate, at the posterior palatine foramen, and
passes forwards through a groove in the hard palate, nearly as far as the incisor
teeth. It supplies the gums, the mucous membrane and glands of the hard
palate, and communicates in front with the termination of the naso-palatine
nerve. While in the posterior palatine canal, it gives off inferior nasal
branches, which enter the nose through openings in the palate bone, and ramify
over the middle meatus, and the middle and inferior spongy bones ; and at its
exit from the canal, a palatine branch is distributed to both surfaces of the soft
palate.
The middle, or external palatine nerve, descends in the same canal as the pre-
ceding, to the posterior palatine foramen, distributing branches to the uvula,
tonsil, and soft palate. It is occasionally wanting.
The posterior, or small palatine nerve, descends with a small artery through
the small posterior palatine canal, emerging by a separate opening behind the
posterior palatine foramen. It supplies the Levator palati and Azygos uvulae
muscles, the soft palate, tonsil, and uvula.
Fig. 376. — The Spheno-palatine Ganglion and its Branches.
The internal hranclies are distributed to the septum, and outer wall of the
nasal fossse. They are the superior nasal (anterior), and the naso-palatine.
The superior nasal branches (anterior), four or five in number, enter the back
part of the nasal fossa by the spheno-palatine foramen. They supply the
mucous membrane covering the superior and middle spongy bones, and that
lining the posterior ethmoidal cells, a few being prolonged to the upper and
back part of the septum. One of these branches (the posterior) is continued
on to the outer wall of the antrum, and there forms a communication with the
anterior dental nerve. At the point of communication a swelling exists, de-
nominated "the ganglion of Bochdalek," the nature of which seems however
"uncertain.
The naso-palatine nerve (Cotunnius) enters the nasal fossa with the other
nasal nerves, and passes inwards across the roof of the nose, below the orifice of
the sphenoidal sinus, to reach the septum; it then runs obliquely downwards
and forwards along the lower part of the septum, to the anterior palatine fora-
654 CRANIAL NERVES.
men, lying between tlie periosteum and mucous membrane. It descends to tlie
roof of the moutli by a distinct canal, whicli opens below in the anterior pala-
tine fossa; the right nerve, also in a separate canal, being posterior to the left
one. In the mouth, they become united, supply the mucous membrane behind
the incisor teeth, and join with the anterior palatine nerve. The naso-j)alatine
nerve occasionally furnishes a few small filaments to the mucous membrane
of the septum.
The posterior hranches are the Yidian and pharyngeal (pterygo-palatine).
The Vidian nerve, if traced from Meckel's ganglion, may be said to arise from
the back part of the spheno-palatine ganglion, and then passes through the
Vidian canal, enters the cartilage filling in the foramen lacerum basis cranii,
and divides into two branches, the large petrosal and the carotid. In its course
along the Vidian canal, it distributes a few filaments to the lining membrane at
the back part of the roof of the nose and septum, and that covering the end of
the Eustachian tube. These are upper posterior nasal branches.
The large petrosal branch [nervus petrosiis si.iperficialis onajor) enters the cra-
nium through the fc^ramen lacerum basis cranii, having pierced the cartilaginous
substance which fills in this aperture. It runs beneath the Casserian ganglion
and dura mater contained in a groove in the anterior surface of the petrous por-
tion of the temporal bone, enters the hiatus Fallopii, and, being continued
through it into the aquasductus Fallopii, joins the gangliform enlargement on
the facial nerve. Properly speaking, this nerve passes from the facial to the
spheno-palatine ganglion, forming its motor root.
The carotid branch is shorter, but larger than the petrosal, of a reddish-gray
color and soft in texture. It crosses the foramen lacerum surrounded by the
cartilaginous substance which fills in that aperture, and enters the carotid canal
on the outer side of the carotid artery, to join the carotid plexus.
This description of the Vidian nerve as a branch from the ganglion, is the.
more convenient anatomically, inasmuch as the nerve is generally dissected /rom
the ganglion, as a single trunk dividing into two branches. But it is more cor-
rect, physiologically, to describe the Vidian as being formed by the union of the
two branches (great petrosal and carotid) from the facial and the sympathetic,
and as running into the ganglion. The filaments, which are described above as
given off' from the Vidian nerve, would then be regarded as branches from the
ganglion which are merely inclosed in the same sheath as the Vidian.
The pharyngeal nerve (pterygo-palatine) is a small branch arising from the
back part of the ganglion, occasionally together with the Vidian nerve. It
passes through the pterygo-palatine canal with the pterygo-palatine artery, and
is distributed to the lining membrane of the pharynx, behind the Eustachian
tube.
Inferior Maxillary Nerve. (Fig. 375.)
The Inferior Maxillary Nerve distributes branches to the teeth and gums of
tlie lower jaw, the integument of the temple and external ear, the lower part of
the face and lower lip, and the muscles of mastication : it also supplies the tongue
with one of its special nerves of the sense of taste. It is the largest of the three
divisions of the fifth, and consists of two portions, the large or sensory root
proceeding from the inferior angle of the Casserian ganglion; and tlic small
or motor root, which passes beneath the ganglion, and unites with the inferior
maxillary nerve, just after its exit through the foramen ovale. Immediately
beneath the base of the skull, this nerve divides into two trunks, anterior and
y)ostorior.
The anterior and smaller division, which receives nearly the whole of the
motor root, divides into branches, which sup])ly the muscles of mastication.
They are the masseteric, deep tem]iMiiil, buccal, ' and two pterygoid.
' Tt, is clonlitfiil wlidli. r tlie buccal liriuich convoys only sensory pnwor to the buccinator, or
motor influence likewise.
INFERIOR MAXILLARY. 655
The masseteric hranch passes outwards, above the External pterygoid muscle,
in front of the temporo-maxillary articulation, and crosses the sigmoid notch,
with the masseteric artery, to the Masseter muscle, in which it ramifies nearly
as far as its anterior border. It occasionally gives a branch to the Temporal
muscle, and a filament to the articulation of the jaw.
The deep temporal branches^ two in number, anterior and posterior, supply the
deep surface of the Temporal muscle. The posterior hranch, of small size, is
placed at the back of the temporal fossa. It is sometimes joined with the
masseteric branch. The anterior hranch is reflected upwards, at the pterygoid
ridge of the sphenoid, to the front of the temporal fossa. It is occasionally
joined with the baccal nerve.
The buccal hranch pierces the External pterygoid, and passes downwards
beneath the inner surface of the coronoid process of the lower jaw, or through
the fibres of the Temporal muscle to reach the surface of the Buccinator, upon
which it divides into a superior and an inferior branch. It gives a branch to
the External pterygoid during its passage through that muscle, and a few as-
cending filaments to the Temporal muscle, one of which occasionally joins with
the anterior branch of the deep temporal nerve. The upper hranch supplies the
integument and upper part of the Buccinator muscle, joining with the facial
nerve round the facial vein. The loiver hranch passes forwards to the angle of
the mouth ; it supplies the integument and Buccinator muscle, as well as the
mucous membrane lining the inner surface of that muscle, and joins the facial
nerve.
The pterygoid branches are two in number, one for each pterygoid muscle.
The hranch of the Internal -pterygoid is long and slender, and passes inwards to
enter the deep surface of the muscle. This nerve is intimately connected at its
origin with the otic ganglion. The hranch of the External pterygoid \^ raost fre-
quently derived from the buccal, but it may be given oft' separately from the
anterior trunk of the nerve.
The posterior and larger division of the inferior maxillary nerve also receives
a few filaments from the motor root. It divides into three branches : auriculo-
temporal, gustatory, and inferior dental.
The AURICULO-TEMPORAL Nerve generally arises by two roots, between which
the middle meningeal artery passes. It runs backwards beneath the External
pterygoid muscle to the inner side of the articulation of the lower jaw. It then
turns upwards with the temporal artery, between the external ear and condyle
of the jaw, under cover of the parotid gland, and escaping from beneath this
structure, divides into two temporal branches. The posterior temporal, the
smaller of the two, is distributed to the upper part of the pinna and the neigh-
boring tissues. The anterior temporal accompanies the temporal artery to the
vertex of the skull, and supplies the integument of the temporal region commu-
nicating with the facial nerve.
The auriculo- temporal nerve has branches of communication with the facial and
otic ganglion. Those joining the facial nerve, usually two in number, pass
forwards behind the neck of the condyle of the jaw, and join this nerve at the
posterior border of the Masseter muscle. They form one of the principal
branches of communication between the facial and the fifth nerve. The fila-
ments of communication with the otic ganglion are derived from the commence-
ment of the auriculo-temporal nerve.
The auricular branches are two in number, inferior and superior. The inferior
auricular arises behind the articulation of the jaw, and is distributed to the ear
below the external meatus ; other filaments twine round the internal maxillary
artery, and communicate with the sympathetic. The superior auricular arises
in front of the external ear, and supplies the integument covering the tragus and
pinna.
Branches to the meatus auditorius, two in number, arise from the point of com-
656 CRANIAL NERVES.
munication between tlie auriculo-temporal and facial nerves, and are distributed
to the meatus.
The branch to the temporo-jnaxillary articulation is usually derived from the
auriculo-temporal nerve.
The parotid branches supply the parotid gland.
The Gustatory or Lingual Nerve, one of the special nerves of the sense of
taste, supplies the papillse and mucous membrane of the tongue. It is deeply
placed throughout the whole of its course. It lies at first beneath the External
pterygoid muscle, together with the inferior dental nerve, being placed to the
inner side of the latter nerve, and is occasionally joined to it by a branch which
crosses the internal maxillary artery. The chorda tympani also joins it at an
acute angle in this situation. The nerve then passes between the Internal ptery-
goid muscle and the inner side of the ramus of the jaw, and cros'ses obliquely to
the side of the tongue over the Superior constrictor muscle of the pharynx, and
beneath the Stylo-glossus muscle and deep part of the submaxillary gland ; the
nerve lastly runs across Wharton's duct, and along the side of the tongue to its
apex, being covered by the mucous membrane of the mouth.
Its branches of coininunication are with the submaxillary ganglion and hypo-
glossal nerve. The branches to the submaxillary ganglion are two or three in
number ; those connected with the hypoglossal nerve form a plexus at the ante-
rior margin of the Hyo-glossus muscle.
Its branches of distribution are few in number. They supply the mucous mem-
brane of the mouth, the gums, the sublingual gland, the conical and fungiform
papillge and mucous membrane of the tongue, the terminal filaments anasto-
mosing at the tip of the tongue with the h^-poglossal nerve.
The Inferior Dental is the largest of the three branches of the inferior
maxillary nerve. It passes downwards with the inferior dental artery, at first
beneath the External pterygoid muscle, and then between the internal lateral,
ligament and the ramus of the jaw to the dental foramen. It then passes for-
wards in the dental canal of the inferior maxillary bone, lying beneath the teeth
as far as the mental foramen, where it divides into two terminal branches, in-
cisor and mental. The incisor branch is continued onwards within the bone to
the middle line, and supplies the canine and incisor teeth. The mental branch
emerges from the bone at the mental foramen, and divides beneath the De-
pressor anguli oris into an external branch, which supplies that muscle, the
Orbicularis oris, and the integument, communicating with the facial nerve; and
an inner branch, which ascends to the lower lip beneath the Quadratus menti ;
it supplies that muscle and the mucous membrane and integument of the lip,
communicating with the facial nerve.
The branches of the inferior dental are, the mylo-hyoid, and dental.
The mylo-hyoid is derived from the inferior dental just as that nerve is about
to enter the dental foramen. It descends in a groove on the inner surface of
the ramus of the jaw, in which it is retained by a process of fibrous membrane.
It supplies the cutaneous surface of the Mylo-hyoid muscle, and the anterior
belly of the Digastric, occasionally sending one or two filaments to the submax-
illary gland.
Tlie dental brandies supply the molar and bicuspid teeth. Tlicy correspond
in number to the fangs of those teeth : each nerve entering the orifice at the
point of the fang, and supplying the pulp of the tooth.
Two small ganglia are connected with the inferior maxillary nerve: the otic,
with the trunk of the nerve; and the submaxillar}^, with its lingual branch, the
gustatory.
Otic Ganglion. (Fig. 877.)
The Otic Ganglion (Arnold's) is a small, oval-shaped, flattened ganglion of a
reddish-gray color, situated immediately below the foramen ovale, on the inner
surface of the inferior maxillary nerve, and round the origin of the internal
SUBMAXILLARY GANGLION.
657
pterygoid nerve. It is in relation, externally^ with the trunk of the inferior
maxillary nerve, at the point where the motor root joins the sensory portion;
internally^ with the cartilaginous part of the Eustachian tube, and the origin of
the Tensor palati muscle; behind it, is the middle meningeal artery.
Fig. 377. — The Otic Ganglion and its Bnnclies.
//
Branches of communication. This ganglion is connected with the inferior
maxillary nerve, and its internal pterygoid branch, by two or three short,
delicate filaments, and also with the auriculo-temporal nerve; from the former
it obtains its motor, from the latter, its sensory root ; its communication with
the symjDathetic being effected by a filament from the plexus surrounding the
middle meningeal artery. This ganglion also communicates with the glosso-
pharyngeal and facial nerves, through the small petrosal nerve continued from
the tympanic plexas.
Its branches of distribution are a filament to the Tensor tympani, and one to
the Tensor palati. The former passes backwards, on the outer side of the
Eustachian tube; the latter arises from the ganglion, near the origin of the
internal pterygoid nerve, and passes forwards.
Submaxillary Ganglion. (Fig. 375.)
The Submaxillary Ganglion is of small size, circular in form, and situated
above the deep portion of the submaxillary gland, near the posterior border of
the Mylo-hyoid muscle, being connected by filaments with the lower border of
the gustatory nerve.
Branches of communication. This ganglion is connected with the gustatory
nerve by a few filaments which join it separately, at its fore and back part. It
also receives a branch from the chorda tympani, by which it communicates
with the facial ; and communicates with the sympathetic by filaments from the
nervi molles — the sympathetic plexus around the facial artery.
Branches of distribution. These are five or six in number ; they arise from
the lower part of the ganglion, and supply the mucous membrane of the mouth
and Wharton's duct, some being lost in the submaxillary gland. According to
Meckel, a branch from this ganglion occasionally descends in front of the Hyo-
glossus muscle, and, after joining with one from the hypoglossal, passes to the
Genio-hyo-glossus muscle.
42
658
CEANIAL NERVES.
Eighth Paie.
The Eightli Pair consists of three nerves, tlie glosso-pharyngeal, pneumo-
gastric, and spinal accessory.
Tlie Glosso-phaeyngeal Neeve is distributed, as its name implies, to the
tongue and pharynx, being the nerve of sensation to the mucous membrane of
Fig. 378. — Nerves of the Eighth
Pair, their Origin, Ganglia, and
(.Communications.
tfugutnr- (iani^t.
Fig. 379.- Course and Distribution of the Eighth
Pair of Nerves.
PneiiTno -yastrt*
the pharynx, fauces, and tonsil ;
of motion to the Pharyngeal
muscles ; and a special nerve
of taste in all the parts of the
tongue to which it is distrib-
uted. It is the smallest of the
three divisions of the eighth
pair, and arises by three or four
filaments, closely connected to-
gether, from the upper part of
the medulla oblongata, imme-
diately behind the olivary
body.
Its deej) origin may be traced
through the fasciculi of the
lateral tract, to a nucleus of
gray matter at the lower part
of the floor of the fourth ven-
tricle external to the fasciculi
teretes. From its superficial
origin, it passes outwards across
the flocculus, and leaves the
skull at the central part of the
jugular foramen, in a separate
sheath of the dura mater and
arachnoid, in front of the pncu-
mogastric and spinal accessory
nerves. In its passage through
the jugular foramen, it grooves
the lower border of the petrous
portion of the temporal bone;
and, at its exit from the skull,
passes forwards between the
jugular vein and internal caro-
tid artery, and descends in
front of the latter vessel, and
GLOSSO-PHARYNGEAL. 659
beneath tlie styloid process and the muscles connected with it, to the lower
border of the Stylo-pharyngeus. The nerve now curves inwards, forming an
arch on the side of the neck, and lying upon the Stylo-pharyngeus and the
Middle constrictor of the pharynx, above the superior laryngeal nerve. It then
passes beneath the Hyo-giossus, and is finally distributed to the mucous mem-
brane of the fauces, and base of the tongue, the mucous glands of the mouth
and tonsil.
In passing through the jugular foramen, the nerve presents, in succession,
two gangliform enlargements. The superior, the smaller, is called the Jugular
<ja7i(jlion, the inferior and larger, the ijetroiis gamjlion^ or the ganglion of
Andersch.
The siq:)erior^ ox jugular ganglion^ is situated in the upper part of the groove
in which the nerve is lodged during its passage through the jugular foramen.
It is of very small size, and involves only the outer side of the trunk of the
nerve, a small fasciculus passing beyond it, which is not connected directly
with it.
The inferior^ or petrous ganglion^ is situated in a depression in the lower border
of the petrous portion of the temporal bone ; it is larger than the former, and
involves the whole of the fibres of the nerve. From this ganglion arise those
filaments which connect the glosso-pharyngeal with other nerves at the base of
the skull.
Its branches of communication are with the pneumogastric, sympathetic, and
facial, and the tympanic branch.
The branches to the pneumogastric are two filaments, one to its auricular
branch, and one to the upper ganglion of the pneumogastric.
The branch to the sympathetic is connected with the superior cervical
ganglion.
The branch of communication with the facial perforates the posterior belly
of the Digastric. It arises from the trunk of the nerve below the petrous
ganglion, and joins the facial just after its exit from the stylo-mastoid foramen.
The tympanic branch (Jacobson's nerve) arises from the petrous ganglion,
and enters a small bony canal in the lower surface of the petrous portion of the
temporal bone ; the lower opening of which is situated on the bony ridge which
separates the carotid canal from the jugular fossa. Jacobson's nerve ascends to
the tympanum, enters that cavity by an aperture in its floor close to the inner
wall, and divides into three branches, which are contained in grooves upon the
surface of the promontory.
Its branches of distribution are, one to the fenestra rotunda, one to the fenestra
ovalis, and one to the lining membrane of the Eustachian tube and tympanum.
Its branches of communication are three, and occupy separate grooves on the
surface of the promontory. One of these arches forwards and downwards to the
carotid canal to join the carotid plexus. A second runs vertically upwards to
join the greater superficial petrosal nerve, as it lies in the hiatus Fallopii. The
third branch, the lesser petrosal, runs upwards and forwards towards the ante-
rior surface of the petrous bone, and passes through a small aperture in the
sphenoid and temporal bones, or through the foramen ovale, to the exterior of
the skull, where it joins the otic ganglion. This nerve, in its course through
the temporal bone, passes by the ganglionic enlargement of the facial, and has
a connecting filament with it.
The branches of the glosso-pharyngeal nerve are the carotid, pharyngeal,
muscular, tonsillar, and lingual.
The carotid branches descend along the trunk of the internal carotid artery as
far as its point of bifurcation, communicating with the pharyngeal branch of
the pneumogastric, and with branches of the sympathetic.
The pharyngeal branches are three or four filaments which unite opposite the
Middle constrictor of the pharynx with the pharjmgeal branches of the pneumo-
gastric, the external laryngeal, and sympathetic nerves, to form the pharyngeal
660 ' CRANIAL NERVES.
plexus, brandies from wliicli perforate the muscular coat of the pliarynx to
supjjly the mucous membrane.
The muscular hranclies are distributed to the Stylo-pharyngeus.
The tonsillar branches supply the tonsil, forming a plexus (circularis tonsil-
laris) around this body, from which branches are distributed to the soft palate
and fauces, where they anastomose with the palatine nerves.
The lingual branches are two in number ; one supplies the mucous membrane
covering the surface of the base of the tongue, the other perforates its substance,
and supplies the mucous membrane and papillae of the side of the organ.
The Sphstal Accessory JSTerve consists of two parts : one, the accessory part
to the vagus, and the other the sjjinal portion.
The accessory part^ the smaller of the two, arises by four or five delicate fila-
ments from the lateral tract of the cord below the roots of the vagus ; these
filaments may be traced to a nucleus of gray matter at the back of the medulla,
below the origin of the vagus. It joins, in the jugular foramen, with the upper
ganglion of the vagus by one or two filaments, and is continued into the vagus
below the second ganglion. It gives branches to the pharyngeal and superior
laryngeal branches of the vagus.
The spinal portion^ firm in texture, arises by several filaments from the lateral
tract of the cord, as low down as the sixth cervical nerve ; the fibres pierce the
tract, and are connected with the anterior horn of the gray matter of the cord.
This portion of the nerve ascends between the ligamentum denticulatum and the
posterior roots of the spinal nerves, enters the skull through the foramen
magnum, and it is then directed outwards to the jugular foramen, through which
it passes, lying in the same sheath as the pneumogastric, separated from it by a
fold of the arachnoid, and is here connected with the accessory portion. At its
exit from the jugular foramen, it passes backwards behind the internal jugular
vein, and descends obliquely behind the Digastric and stylo-hyoid muscles to
the upper part of the Sterno-mastoid. It pierces that muscle, and passes
obliquely across the suboccipital triangle, to terminate in the deep surface of
the Trapezius, This nerve gives several branches to the Sterno-mastoid during
its passage through it, and joins in its substance with, branches from the third
cervical. In the suboccipital triangle it joins with the second and third cervical
nerves, and assists in the formation of the cervical plexus, and occasionally of
the great auricular nerve. On the front of the Trapezius, it is reinforced by
branches from the third, fourth, and fifth cervical nerves, joins with the j)oste-
rior branches of the spinal nerves, and is distributed to the Trapezius, some
filaments ascendina; and others descending in the substance of the muscle as far
as its inferior angle.
The Pneumogastric Nerve (7iervus vagus or par vagum), one of the three
divisions of the eighth pair, has a more extensive distribution than any of
the other cranial nerves, passing through the neck and thorax to the upper
])art of the abdomen. It is composed of both motor and sensitive filaments.
It supplies the organs of voice and respiration with motor and sensitive fibres ;
and the pharynx, oesophagus, stomach, and heart with motor influence; Its
superficial origin is by eight or ten filaments from the lateral tract immediately
behind the olivary body and below the glosso-pharyngeal; its fibres may,
Jiowever, be traced deeply througli the fasciculi of the medulla, to terminate in
a gray nucleus near the lower part of the floor of the fourth ventricle. The
filaments become united, and form a flat cord, which ])asses outwards across
the flocculus to the jugular foramen, through which it emerges from the cranium.
In passing through this opening, the pneumogastric accompanies the spinal
accessor}^, being (;ontaincd in the same sheath of dura mater with it, a membra-
nous septum separating it from the glosso-])liaryngcal, which lies in front. The
nerve in this situation presents a well-marked ganglionic enlargement, which
is called ganglion jugulare^ or the ganglion of the root of the pneumogas/ric: to
it the accessory part of the spinal accessory nerve is connected. After the exit
PNEUMOGASTRIC. 661
of the nerve from the jugular foramen, a second ganglioform swelhng is formed-
upon it, called the ganglion inferius^ or the ganglion of the trunk of the nerve;
below which it is again joined by filaments from the accessary nerve. The
nerve passes vertically down the neck within the sheath of the carotid vessels,
lying between the internal carotid artery and internal jugular vein as far as
the thyroid cartilage, and then between the same vein and the common carotid
to the root of the neck. Here the course of the nerve becomes different on the
two sides of the body.
On the right side^ the nerve passes across the subclavian artery between it
and the subclavian vein, and descends by the side of the trachea to the back
part of tlie root of the lung, where it spreads out in a plexiform network (pos-
terior pulmonary), from the lower part of which two cords descend upon the
oesophagus, on which they divide, forming, with branches from the opposite
nerve, the oesophageal plexus ; below, these branches are collected into a single
cord, which runs along the back part of the oesophagus, enters the abdomen,
and is distributed to the posterior surface of the stomach, joining the left side
of the coeliac plexus, and the splenic plexus.
On the left side, the pneumogastric nerve enters the chest between the left
carotid and subclavian arteries, behind the left innominate vein. It crosses the
arch of the aorta, and descends behind the root of the left lung and along the
anterior surface of the oesophagus to the stomach, distributing branches over
its anterior surface, some extending over the great cul-de-sac, and others along
the lesser curvature. Filaments from these latter branches enter the gastro-
hepatic omentum, and join the left hepatic plexus.
The ganglion of the root is of a grayish color, circular in form, about two lines
in diameter, and resembles the ganglion on the large root of the fifth nerve.
Connecting branches. To this ganglion the accessory portion of the spinal
accessory nerve is connected by several delicate filaments ; it also has an anasto-
motic twig with the petrous ganglion of the glosso-pharyngeal, with the facial
nerve by means of the auricular branch, and with the sympathetic by means
of an ascending filament from the superior cervical ganglion.
The ganglion of the trunk (inferior) is a plexiform cord, cylindrical in form,
of a reddish color, and about an inch in length ; it involves the whole of the
fibres of the nerve, except the portion of the nerve derived from the spinal
accessory, which blends with the nerve beyond the ganglion.
Connecting branches. This ganglion is connected with the hypoglossal, the
superior cervical ganglion of the sympathetic, and the loop between the first
and second cervical nerves.
The l/ranches of the pneumogastric are —
In the jugular fossa . . • . Auricular.
r Pharyngeal.
In the neck . . . I Superior laryngeal.
I itecurreut laryngeal.
[ Cervical cardiac.
r Thoracic cardiac.
T .1 ,1 Anterior pulmonary.
In the thorax . . . . i -n . • ^ i "^
I Posterior pulmonary.
• [ QEaophageal.
In the abdomen . . . Gastric.
The auricular branch (Arnold's) arises from the ganglion of the root, and is
joined soon after its origin by a filament from the glosso-pharyngeal : it crosses
the jugular fossa to an opening near the root of the styloid process. Traversing
the substance of the temporal bone, it crosses the aqufeductus Fallopii about
two lines above its termination at the stylo-mastoid foramen; it here gives off
an ascending branch, which joins the facial, a,nd a descending branch, which
anastomoses with the posterior auricular branch of the same nerve : the con-
662 CRANIAL NERVES.
tinuation of the nerve readies tlie surface between the mastoid process and the
external auditory meatus, supplies the integument at the back part of the pinna,
and communicates with the branches of the auricularis ma2:nus.
The pharyngeal branch^ the principal motor nerve of the pharynx and soft
palate, arises from the upper part of the inferior ganglion of the pneumogastric,
receiving a filament from the accessory portion of the spinal accessory ; it passes
across the internal carotid artery (in front or behind), to the upper border of
the Middle constrictor, where it divides into numerous filaments, which anasto-
mose with those from the glosso-pharyngeal, superior laryngeal, and sympa-
thetic, to form the pharyngeal plexus, from which branches are distributed to
the muscles and mucous membrane of the pharynx. As this nerve crosses the
internal carotid, some filaments are distributed, together with those from the
glosso-pharyngeal, upon the wall of this vessel.
The sui:)erior laryngeal is the nerve of sensation to the larynx. It is larger
than the preceding, and arises from the middle of the inferior ganglion of the
pneumogastric. It descends, by the side of the pharj-nx, behind the internal
carotid, where it divides into two branches, the external and internal larjmgeal.
The external laryngeal branch, the smaller, descends by the side of the
larynx, beneath the Sterno-thyroid, to supply the Crico-thyroid muscle and the
thyroid gland. It gives branches to the pharyngeal plexus, and the Inferior
constrictor, and communicates with the superior cardiac nerve, behind the
common carotid.
The internal laryngeal branch descends to the opening in the thyro-hyoid
membrane, through Avhich it passes with the superior laryngeal artery, and is
distributed to the mucous membrane of the larynx, and the Arytenoid muscle,
anastomosing with the recurrent laryngeal.
The branches to the mucous membrane are distributed, some; in front to the
epiglottis, the base of the tongue and the epiglottidean glands; while others _
pass backwards, in the aryteno-epiglottidean fold, to supply the mucous mem-
brane surrounding the superior orifice of the larynx, as well as the membrane
which lines the cavity of the larynx as low down as the vocal cord.
The filament to the Arytenoid muscle is distributed partly to it, and partly
to the mucous lining of the larynx.
The filament which joins with the recurrent laryngeal descends beneath the
mucous membrane on the posterior surface of the larynx, behind the lateral
part of the thyroid cartilage, where the two nerves become united.
The inferior or recurrent laryngeal^ so called from its reflected course, is the
motor nerve of the larynx. It arises on the right side, in front of the subcla-
vian artery ; winds from before backwards round that vessel, and ascends
obliquely to the side of the trachea, behind the common carotid and inferior
thyroid arteries. On the left side, it arises in front of the arch of the aorta and
winds from before backwards round the aorta at the point where the obliterated
remains of the ductus arteriosus are connected with it, and then ascends to the
side of the trachea. The nerves on both sides ascend in the groove between
the trachea and oesophagus, and, passing under the lower border of the Inferior
constrictor muscle, enter the larynx behind the articulation of the inferior cornu
of the thyroid cartilage with the cricoid, being distributed to all the muscles of
the larynx, excepting the Crico-thyroid, and joining with the su]:)crior laryngeal.
The recurrent lar^aigeal, as it winds round tlie subclavian artery and aorta,
gives off several cardiac filaments, which unite witli the cardiac branches from
the pneumogastric and sympathetic. As it ascends in the neck, it gives off
(X}SO])ljageal branches, more numerous on the left than on the right side, which
supply the mucous membrane and muscular coat of the oesophagus; tracheal
branches to the mucous membrane and muscular fibres of the trachea ; and
some pharyngeal filaments to the Inferior constrictor of the pharynx.
The cervical cardiac hranches, two or three in number, arise from the ymonmo-
gastric, at the upper and lower part of the neck.
ORIGIN OF CRANIAL NERVES. 663
The superior brandies are small, and communicate with the cardiac branches
of the sympathetic, and with the great cardiac plexus.
The inferior cardiac branches, one on each side, arise at the lower part of the
neck, just above the first rib. On the right side, this branch passes in front of
the arteria innominata, and anastomoses with the superior cardiac nerve. On
the left side, it passes in front of the arch of the aorta, and anastomoses either
with the superior cardiac nerve, or with the cardiac plexus.
The thoracic cardiac branches^ on the right side, arise from the trunk of the
pneumogastric, as it lies by the side of the trachea: passing inwards, they
terminate in the deep cardiac plexus. On the left side they arise from the left
recurrent laryngeal nerve.
The anterior pulmonary branches^ two or three in number, and of small size,
are distributed on the anterior aspect of the root of the lungs. They join with
filaments from the sympathetic, and form the anterior pulmonary plexus.
T]iQ posterior pulmonary branches^ more numerous and larger than the ante-
rior, are distributed on the posterior aspect of the root of the lung : they are
joined by filaments from the third and fourth thoracic ganglia of the sympa-
thetic, and form the posterior pulmonary plexus. Branches from both plexuses
accompany the ramifications of the air-tubes through the substance of the lungs.
The oesophageal branches are given off from the pneumogastric both above and
below the pulmonary branches. The lower are more numerous and larger than
the upper. They form, together with branches from the opposite nerve, the
oesophageal plexus.
The gastric branches are the terminal filaments of the pneumogastric nerve.
The nerve on the right side is distributed to the posterior surface of the stomach,
and joins the left side of the coeliac plexus and the splenic plexus. The nerve
on the left side is distributed over the anterior surface of the stomach, some
filaments passing across the great cul-de-sac, and others along the lesser curva-
ture. They unite with branches of the right nerve and sympathetic, some fila-
ments passing through the lesser omentum to the left hepatic plexus.
For the following brief account of the most recent views relating to the origin
of the cranial nerves, the editor is indebted to his friend Dr. Lockhart Clarke.
The third cerebral nerve arises chiefly from two large masses of gray sub-
stance at the floor of the iter e tertio ad quartum ventriculum beneath the
corpora quadrigemina.
The fourth arises from two nuclei at the floor of the iter e tertio ad quartum
ventriculum, and from the valve of Vieussens, where the opposite nerves decus-
sate with each other.
The large root of the fifth or trigeminal arises chiefly from the gray tubercles
of Rolando, or the upper expanded extremities of the posterior gray horns of
the spinal cord ; the small or motor root arises from two masses of large multi-
polar cells situated each on the inner side, and close to the gray tubercle, and
intimately connected with it.
The sixth nerve arises in common with the facial from the gray substance of
the fasciculus teres on the floor of the fourth ventricle.
The facial nerve has two origins : 1. From the gray substance of the fasciculus
teres on the floor of the fourth ventricle. 2. From the nucleus of the motor root
of the trigeminus ; between these two origins it forms a loop along the floor of
the ventricle.
The auditory nerve has three origins: 1. From the superior vermiform pro-
cess of the cerebellum. 2 and 3. From the inner and outer auditory nuclei
formed chiefly by the gray substance of the posterior pyramid and restiform
body.
The vagus and glosso- pharyngeal nerves have each two origins : 1. From a
special nucleus in the floor of the fourth ventricle. 2. From the anterior or
motor part of the medulla.
664 CRANIAL NERVES.
The spinal accessory nerve has three origins : 1. The lower roots from the
anterior gray horn of the spinal eord in common with the motor roots of the
cervical nerves. 2. From the gray nucleus of the hypoglossal nerve. 3. From
a special nucleus behind the central canal of the medulla oblongata.
For further information on the origin of these nerves, and on the connection between the'r
several nuclei, see Dr. Lockhart Clarke's memoir " On the Intimate Structure of the Brain,"
1st and 2d Ser. Phil. Trans., 1858 and 1868.
For fuller detail concerning the Cranial Nerves, the student may refer to F. Arnold's " Icones
Nervorum Capitis," and to the other authors referred to on page 636.
The Spinal Nerves.
The Spinal Nerves are so called, because thej take tlieir origin from the
spinal cord, and are transmitted tlirougli the intervertebral foramina • on either
side of the spinal column. There are thirty-one pairs of spinal nerves, which
are arranged into the following groups, corresponding to the region of the spine
through which they pass: — •
Cervical
Dorsal
Lumbar
Sacral
Coccygeal
It will be observed, that each group of nerves corresponds in number with
the vertebrse in that region, except the cervical and coccygeal.
Each spinal nerve arises by two roots, an anterior, or motor root, and a
posterior, or sensory root.
8
pairs
12
a
5
u
5
u
1
a
EooTS OF THE Spinal ISTeeves.
The anterior 7'oots arise somewhat irregularly from a linear series of foramina,
on the antero-lateral column of the spinal cord, gradually approaching towards
the anterior median fissure as they descend.
The fibres of the anterior roots, according to the researches of Dr. Lockhart
Clarke, are attached to the anterior part of the antero-lateral column ; and, after
penetrating horizontally through the longitudinal fibres of this tract, enter the
gray substance, where their fibrils cross each other and diverge in all directions,
like the expanded hairs of a brush, some of them running more or less longi-
tudinally upwards and downwards, and others decussating with those of the
opposite side through the anterior commissure in front of the central canal.
KoUiker states that many fibres of the anterior root enter the lateral column of
the same side, where, turning upvmrds^ they pursue their course as longitudinal
fibres. In other respects, the description of the origin of the anterior roots by
these observers is very similar.
The posterior roots are all attached immediately to the posterior white columns
only ; but some of them pass through the gray substance into both the lateral
and anterior white columns. Within the gray substance, they run, longitudi-
nally, upwards and downwards, transversely, through the posterior commissure
to the opposite side, and into the anterior column of their own side.
The posterior roots of the nerves are larger, but the individual filaments are
finer and more delicate than those of the anterior. As their component fibrils
pass outwards, towards the aperture in the dura mater, they coalesce into two
bundles, receive a tubular sheath from that membrane, and enter the ganglion
which is developed upon each root.
The posterior root of the first cervical nerve forms an exception to these
characters. It is smaller than the anterior, has frequently no ganglion developed
upon it, and, when the ganglion exists, it is often situated within the dura
mater.
The anterior roots are the smaller of the two, devoid of any ganglionic enlarge-
ment, and their component fibrils are collected into two bundles, near the inter-
vertebral foramina.
(665)
666 SPINAL NERVES.
Ganglia of the Spinal JSTeeves.
A ganglion is developed upon tlie posterior root of each of tlie spinal nerves.
These ganglia are of an oval form, and of a reddish color ; they bear a propor-
tion in size to the nerves upon which they are formed, and are placed in the
intervertebral foramina, external to the point where the nerves perforate the
dura mater. Each ganglion is bifid internally, where it is joined by the two
bundles of the posterior root, the two portions being united into a single mass
externally. The ganglia upon the first and second cervical nerves form an
exception to these characters, being placed on the arches of the vertebra; over
which the nerves pass. The ganglia, also, of the sacral nerves are placed within
the spinal canal ; and that on the coccygeal nerve, also in the canal about the
middle of its posterior root. Immediately beyond the ganglion, the two roots
coalesce, their fibres intermingle, and the trunk thus formed passes out of the
intervertebral foramen, and divides into an anterior branch, for the supply of
the anterior part of the body ; and a posterior branch for the posterior part, each
branch containing fibres from both roots.
Anterior Branches of the Spinal Nerves.
The anterior hranches of the spinal nerves supply the parts of the body in front
of the spine, including the limbs. They are for the most part larger than the
posterior branches ; this increase of size being proportioned to the larger extent
of structures they are required to supply. Each branch is connected by slender
filaments with the sympathetic. In the dorsal region, the anterior branches of
the spinal nerves are completely separate from each other, and are uniform in
their distribution; but in the cervical, lumbar, and sacral regions, they form
intricate plexuses previous to their distribution.
Posterior Branches of the Spinal Nerves.
^]iQ posterior hranches of the spinal nerves are generall}^ smaller than the ante-
rior : they arise from the trunk resulting from the union of the roots, in the
intervertebral foramina; and, passing backwards, divide into external and in-
ternal branches, which are distributed to the muscles and integument behind
the spine. The first cervical and lower sacral nerves are exceptions to these
characters.
Cervical Nerves.
The roots of the cervical nerves increase in size from the first to the fifth, and
then maintain the same size to the eighth. The posterior roots bear a propor-
tion to the anterior as 3 to 1, which is much greater than in any other region,
the individual filaments being also much larger than those of the anterior roots.
In direction, the roots of the cervical are less oblique than those of the other
spinal nerves. The first cervical nerve is directed a little upwards and out-
wards; the second is horizontal; the others are directed obliquely downwards
and outwards, the lowest being the most oblique, and consequently longer than
the upper, the distance between their place of origin and their point of exit from
the spinal canal never exceeding the depth of one vertebra.
The trunk of the first cervical nerve {snhoccipital) leaves the spinal canal,
between the occipital bone and the posterior arch of the atlas; the second,
between the posterior arch of the atlas and the lamina of the axis; and the
eighth (tlie last), between the last cervical and first dorsal vortebrrc.
Each nerve, at its exit from the intervertebral foramen, divides into an ante-
rior and a posterior T)ranch. Tlie anterior branches of the four upper cervical
nerves form the cervical plexus. Tlic anierior branches of the four lower cervi-
cal nerves, together with llie first dorsal, form the brachial plexus.
CERVICAL PLEXUS.
667
Ajstterioe Branches of the Cervical NerveSs
The anterior branch of the first, or suhoccipital fierve, is of small size. It
escapes from the spinal canal, through a groove upon the posterior arch of the
atlas. In this groove it lies beneath the vertebral artery, to the inner side of
the Eectus capitis lateralis. As it crosses the foramen in the transverse process
of the atlas, it receives a filament from the sympathetic. It then descends, in
front of this process, to communicate with an ascending branch from the second
cervical nerve.
Communicating filaments from this nerve join the pneumogastric, the hypo-
glossal and sympathetic, and some branches are distributed to the Eectus
lateralis, and the two Anterior recti. According to Valentin, the anterior
branch of the suboccipital also distributes filaments to the occipito-atloid articu-
lation, and mastoid process of the temporal bone.
The anterior branch of the second cervical nerve escapes from the spinal canal,
between the posterior arch of the atlas and the lamina of the axis, and, passing
forwards on the outer side of the vertebral artery, divides in front of the Inter-
transverse muscle, into an ascending branch, which joins the first cervical; and
two descending branches which join tlie third.
The anterior branch of the third cervical nerve is double the size of the pre-
ceding. At its exit from the intervertebral foramen, it passes downwards and
outwards beneath the Sterno- mastoid, and divides into two branches. The
ascending branch joins the anterior division of the second cervical, communi-
cates with the sympathetic and spinal accessory nerves, and subdivides into the
superficial cervical and great auricular nerves. The descending branch passes
down in front of the Scalenus anticus, anastomoses with the fourth cervical
nerve, and becomes continuous with the clavicular nerves.
The anterior branch of the fourth cervical is of the same size as the preceding.
It receives a branch from the third, sends a communicating branch to the fifth
cervical, and passing downwards and outwards, divides into numerous filaments,
which cross the posterior triangle of the neck, towards the clavicle and acromion.
It usually gives a branch to the phrenic nerve, whilst it is contained in the
intertransverse space.
The anterior branches of the fifth, sixth, seventh, and eighth cervical nerves are
remarkable for their large size. They are much larger than the preceding-
nerves, and are all of equal size. They assist in the formation of the brachial
plexus.
Cervical Plexus.
The Cervical Plexus (Fig. 374) is formed by the anterior branches of the four
upper cervical nerves. It is situated opposite the four upper vertebra, resting
upon the Levator anguli scapulee, and Scalenus medius muscles, and covered in
by the Sterno-mastoid.
Its branches may be divided into two groups, superficial and deep, which
may be thue arranged : — -
i Superficialis colli.
Ascending I Auricularis magnus.
( Occipitalis minor.
Superficial
[ Descending. Supraclavicular
Sternal.
Clavicular.
Acromial.
Deep
Internal
External
r Communicating.
I Muscular.
Communicans noni.
[ Phrenic.
Communicating.
Muscular.
G68 SPINAL NERVES.
Superficial Branches of the Cervical Plexus,
The Superficialis Colli arises from the second aad third cervical nerves, turns
round tlie posterior border of the Sterno-mastoid about its middle, and passing
obliquely forAvards beneath the external jugular vein to the anterior border of
that muscle, perforates the deep cervical fascia, and divides beneath the Pla-
tysma into two branches, which are distributed to the anterior and lateral parts
of the neck.
The ascending hranch gives off a filament, which accompanies the external
jugular vein ; it then passes upwards to the submaxillary region, and divides •
into branches, some of which form a plexus with the cervical branches of the
facial nerve beneath the Platysma: others pierce that muscle, supply it, and
are distributed to the integument of the upper half of the neck, at its fore part,
as high as the chin.
The descending hranch pierces the Platysma, and is distributed to the integu-
ment of the side and front of the neck, as low as the sternum.
This nerve is occasionally represented by two or more filaments.
The Auricularis Magnus is the largest of the ascending branches. It arises
from the second and third cervical nerves, winds round the posterior border of
the Sterno-mastoid, and after perforating the deep fascia, ascends upon that
muscle beneath the Platysma to the parotid gland, where it divides into nume-
rous branches.
^h.Q facial branches pass across the parotid, and are distributed to the integu-
ment of the face : others penetrate the substance of the gland, and communicate
with the facial nerve.
The posterior or auricular branches ascend vertically to supply the integument
of the back part of the pinna, communicating with the auricular branches of
the facial and pneumogastric nerves.
The mastoid branch joins the posterior auricular branch of the facial, and
crossing the mastoid process, is distributed to the integument behind the ear.
The Occipitalis Minor arises from the second cervical nerve ; it curves round
the posterior border of the Sternormastoid above the preceding, and ascends
vertically along the posterior border of that muscle to the back part of the side
of the head. Near the cranium it perforates tfee deep fascia, and is continued
upwards along the side of the head behind the e^T, supplying the integument
and Occipito-frontalis muscle, and communicating with the occipitalis major,
auricularis magnus, and posterior auricular branch of the facial.
This nerve gives off an auricular branchy which supplies the Attollens aurem
and the integument of the upper, and back part of the auricle. This branch is
occasionally derived from the great occipital nerve. The occipitalis minor
varies in size; it is occasionally double.
The Descending or supraclavicular branches arise from the third and fourth
cervical nerves; emerging beneath the posterior border of the Sterno-mastoid,
they descend in the interval between that muscle and the Trapezius, and divide
into branches, which are arranged, according to their position, intt) three groups.
The inner or sternal branch crosses obliquely over the clavicular and sternal
attachments of the Sterno-mastoid, and supplies the integument as far as the
median line.
The middle or clavicvlar branrJi, crosses the clavicle, and supplies the integu-
ment over the Pectoral and Deltoid muscles, communicating with the cutaneous
branches of the up])cr intercoslal ncrvcss. Not unfrequently, the clavicular
brancli passes tlirougli a foramen in the clavicle, at the junction of the outer
with the middle third of the bone.
The external or acromial branch passes oblirpiely across the outer surface of
the Trapezius and the acr< union, and supplies the integument of the upper
and biK',l\ ]»art of the sliouldcr.
CERVICAL PLEXUS. 669
Deep Branches of the Cervical Plexus. Internal Series.
The communicating hranches consist of several filaments, wliich pass from tlie
loop between the first and second cervical nerves in front of the atlas to the
pneumogastric, hypoglossal, sympathetic, and fifth cervical.
Muscular hranches supply the Anterior recti and Eectus lateralis muscles;
they proceed from the first cervical nerve, and from the loop formed between
it and the second.
The Communicans Noni (Fig. 374) consists nsnally of two figments, one being
derived from the second, and the other from the third cervical.- These filaments
pass vertically downwards on the outer side of the internal jugular vein, cross
in front of the vein a little below the middle of the neck, and form a loop with
the descendens noni in front of the sheath of the carotid vessels. Occasionally
the junction of these nerves takes place within the sheath.
The Phrenic Nerve {internal respiratory of Bell) arises from the third and fourth
cervical nerves, and receives a communicating branch from the fifth. It descends
to the root of the neck, lying obliquely across the front of -the Scalenus anticus,
passes over- the first part of the subclavian artery, between it and the subclavian
vein, and, as it enters the chest, crosses the internal mammary artery near its
root. Within the chest, it descends nearly vertically in front of the root of the
lung, and by the side of the pericardium, between it and the mediastinal portion
of the pleura, to the Diaphragm, where it divides into branches, which separately
pierce that muscle, and are distributed to its under surface.
The two phrenic nerves differ in their length, and also in their relations at
the upper part of the thorax.
The right nerve is situated more deeply, and is shorter and more vertical in
direction than the left ; it lies on the outer side of the right vena innominata
and superior vena cava.
The left nerve is rather longer than the right, from the inclination of the heart
to the left side, and from the Diaphragm being lower on this than on the oppo-
site side. At the upper part of the thorax, it crosses in front of the arch of the
aorta to the root of the lung.
Each nerve supplies filaments to the pericardium and pleura, and near the
chest is joined by a filament from the sympathetic, by another derived by tJie
fifth and sixth cervical nerves, and occasionally, by one from the union of the
descendens noni with the spinal nerves ; this filament is found, according to Swan,
only on the left side. It is also usually connected by a filament with the nerve
to the subclavius muscle.
From the right nerve^ one or two filaments pass to join in a small ganglion
Avith the phrenic branches of the solar plexus ; and branches from this ganglion
are distributed to the hepatic plexus, the suprarenal capsule, and inferior vena
cava. From the left nerve^ filaments pass to join the phrenic plexus, but without
any ganglionic enlargement.
Deep Branches of the Cervical Plexus. External Series.
Cominunicating hranches.^ The cervical plexus communicates with the spinal
accessory nerve, in the substance of the Sterno-mastoid muscle, in the occipital
triangle, and beneath the Trapezius.
Muscular hranches are distributed to the Sterno-mastoid, Levator anguli sca-
pulae, Scalenus medius and Trapezius.
The branch for the Sterno-mastoid is derived from the second cervical, the
Levator anguli scapulse receiving branches from the third, and the Trapezius
branches from the third and fourth.
670 SPINAL NERVES.
Posterior Branches of the Cervical Nerves.
The posterior branches of tlie cervical nerves, with the exception of those of
the first two, pass bacli wards, and divide, behind the posterior Intertransverse
muscles, into external and internal branches.
The external branches supply the muscles at the side of the neck, viz., the
Cervicalis ascendens, Transversalis colli, and Trachelo- mastoid.
The external branch of the second cervical nerve is the largest ; it is often
joined with the third, and supplies the Complexus, Splenius, and Trachelo-mas-
toid muscles.
The internal branches^ the larger, are distributed differently in the upper and
lower part of the neck. Those derived from the third, fourth, and fifth nerves
pass between the Semispinalis and Complexus muscles, and having reached the
spinous processes, perforate the aponeurosis of the Splenius and Trapezius, and
are continued outwards to the integument over the Trapezius ; whilst those de-
rived from the three lowest cervical nerves are the smallest, and are placed
beneath the Semispinalis, which they supply, and do not furnish any cutaneous
filaments. These internal branches supply the Complexus, Semispinalis colli,
Interspinales, and Multifidus spinse.
The posterior branches of the first three cervical nerves require a separate
description.
The posterior branch of the first cervical nerve {suboccipital) is larger than the
anterior, and escapes from the spinal canal between the occipital bone and the
posterior arch of the atlas, lying behind the vertebral artery. It enters the tri-
angular space formed by the Rectus posticus major, the Obliquus superior, and
Obliquus inferior, and supplies the Recti and Obliqui muscles, and the Com-
plexus. From the branch which supplies the Inferior oblique a filament is given
off, which joins the second cervical nerve. This nerve also occasionally gives
off a cutaneous filament, which accompanies the occipital artery, and commu-
nicates with the occipitalis major and minor nerves.
The posterior division of the first cervical has no branch analogous to the
external branch of the posterior cervical nerves.
The posterior branch of the second cervical nerve is three or four times greater
than the anterior branch, and the largest of all the posterior cervical nerves. It
emerges from the spinal canal between the posterior arch of the atlas and lamina
of the axis, below the Inferior oblique. It supplies this muscle, and receives
a communicating filament from the first cervical. It then divides into an ex-
ternal and an internal branch ,
The internal branch, called, from its size and distribution, the occipitalis onaj'or,
ascends obliquely inwards between the Obliquus inferior and Complexus, and
pierces the latter muscle and the Trapezius near their attachments to the cra-
nium. It is now joined by a filament from the third cervical nerve, and
ascending on the back part of the head with the occipital artery, divides into
two branches, which supply the integument of the scalp as far forwards as the
vertex, communicating with the occipitalis minor. It gives off an auricular
branch to the back, part of the ear, and muscular branches to the Complexus.
The posterior branch of the third cervical is smaller than the preceding, but
larger than tlie fourth ; it differs from the posterior branches of the other cervictil
nerves in its supplying an additional filament to the integument of the occiput.
This occipital branch arises from the internal or cutaneous branch beneath the
Trapezius ; it pierces that muscle, and supplies the skin on the lower and back
part of the head. It lies to the inner side of the occipitalis major, with which it
is connected.
The internal branches of the posterior divisions of the first three cervical
nerves are occasionally joined beneath the Complexus by communicating
branches. This communication is described by Cruveilhier as the posterior cervi-
cal plexus.
BRACHIAL PLEXUS.
671
U^ttS f'.
CommiinicatiTiff with PiireniO
Sup ra -Soapu2ar
« If Clavicle
The Brachial Plexus. (Fig. 380.)
The Brachial Plexus is formed by the union of the anterior branches of the
four lower cervical and first dorsal nerves. It extends from the lower part of
the side of the neck to the axilla. It is very broad and presents little of a plexi-
form arrangement at its commencement, is narrow opposite the clavicle, becomes
broad, and forms a more dense interlacement in the axilla, and divides opposite
the co'racoid process into numerous branches for the supply of the upper limb.
The nerves which form the
plexus are all similar in size, Fig. 380.— Plau of the Brachial Plexus.
and their mode of communi-
cation is the following. The
fifth and sixth nerves unite near
their exit from the spine into a
common trunk ; the seventh
nerve joins this trunk near
the outer border of the Middle
scalenus ; and the three nerves
thus form one large single cord.
The eighth cervical and first
dorsal nerves unite behind the
Anterior scalenus into a com-
mon trunk. Thus two large
trunks are formed, the upper
one by the union of the fifth,
sixth, and seventh cervical ; and
the lower one by the eighth cer-
vical and first dorsal. These
two trunks accompany the sub-
clavian artery to the axilla,
lying upon its outer side, the
trunk formed by the union of
the last cervical and first dorsal
being nearest to the vessel. Op-
posite the clavicle, and some-
times in the axilla, each of these
cords gives off a fasciculus, by
the union of which a third trunk is formed, so that in the middle of the axilla
three cords are found, one lying on the outer side of the axillary artery, one on
its inner side, and one behind.^ The brachial plexus communicates with the
cervical plexus by a branch from the fourth to the fifth nerve, and with the
phrenic nerve by a branch from the fifth cervical, which joins that nerve on
the Anterior scalenus muscle: the cervical and first dorsal nerves are also joined
by filaments from the middle and inferior cervical ganglia of the sympathetic,
close to their exit from the intervertebral foramina.
' This is the usual mode of formation of, the plexus ; but it is also very common for the third,
or posterior, cord to be formed by the seventh cervical nerve, running undivided, and receiving
a branch from each of the other cords, or the seventh nerve may bifurcate, one branch of bifurca-
tion joining each of the other cords. From these two cords the third trunk is formed, as described
in the text. Mr. R. C. Lucas describes an arrangement differing slightly from that last mentioned,
and which he regards as the common one, having met with it in 27 out of 30 dissections. The
seventh nerve bifurcates, and so does the united cord of the fifth and sixth nerves. One of the
branches of bifurcation of the seventh nerve, along with that of the united fifth and sixth nerves,
forms the external cord of the plexus. The other branch of bifurcation of the united fifth and sixth
along with that of the seventh nerve forms a large cord, which receives a small branch from the
united eighth cervical and first dorsal to form the posterior cord. The rest of the united eighth
cervical and first dorsal nerves is continued as the internal cord. (See Mr. Lucas's paper and
drawing in the Guy' s Hospital Reports, 1875.) Henle's description is substantially the same.
672 SPINAL NEEVES.
Relations. In the nech^ tlie bracliial plexus lies at first between the Anterior
and Middle scaleni muscles, and then above and to the outer side of the subcla-
vian artery; it then passes behind the clavicle and Subclavius muscle, lying upon
the first serration of the Serratus magnus, and the Subscapularis muscles. In
the axilla^ it is placed on the outer side of the first portion of the axillary artery ;
it surrounds the artery in the second part of its course, one cord lying upon the
outer side of that vessel, one on the inner side, and one behind it ; and at the
lower part of the axillary space gives off its terminal branches to the upper
extremity.
Branches. The branches of the brachial plexus are arranged into two groups
viz., those given off above the clavicle, and those below that bone.
Branches above the Clavicle.
Communicating. Posterior thoracic.
Muscular. Suprascapular.
The com'niunicating branch with the phrenic is derived from the fifth cervical
nerve ; it joins the phrenic on the Anterior scalenus muscle.
The trmscular branches supply the Longus colli, Scaleni, Rhomboidei, and
Subclavius muscles. Those for the Scaleni and Longus colli arise from the
lower cervical nerves at their exit from the intervertebral foramina. The
rhomboid branch arises from the fifth cervical, pierces the Scalenus medius, and
passes beneath the Levator anguli scapulae, which it occasionally supplies, to the
Rhomboid muscles. The nerve to the Subclavius is a small filament, which
arises from the trunk formed by the junction of the fifth and sixth cervical
nerves ; it descends in front of the subclavian artery to the Subclavius muscle,
and is usually connected by a filament with the phrenic nerve.
The posterior thoracic nerve (long thoracic, external respiratory of Bell) (Fig.
383) supplies the Serratus magnus, and is remarkable for the length of its
course. It arises by two roots, from the fifth and sixth cervical nerves, imme-
diately after their exit from the intervertebral foramina. These unite in the
substance of the Middle scalenus muscle, and, after emerging from it, the nerve
passes down behind the brachial plexus and the axillary vessels, resting on the
outer surface of the Serratus magnus. It extends along the side of the chest
to the lower border of that muscle, and supplies it with numerous filaments.
The suprascapular nerve (Fig. 384) arises from the cord formed by the fifth,
sixth, and seventh cervical nerves; passiug obliquely outwards beneath the
Trapezius, it enters the supraspinous fossa, through the notch in the upper
border of the scapula ; and, passing beneath the Supraspinatus muscle, curves
in front of the spine of the scapula to the infraspinous fossa. In the supra-
spinous fossa, it gives off two branches to the Supraspinatus muscle, and an
articular filament to the shoulder-joint ; and in the infraspinous fossa, it gives
off two branches to the Infraspinatus muscle, besides some filaments to the
shoulder-joint and scapula.
Branches below the Clavicle.
To chest .... Anterior thoracic.
To shoulder . . . ] Subscapular.
Circumllox.
To ai'in, fore-arm, and hand
Musculo-cutaneous.
Internal cutaneous.
Lesser internal cutaneous.
Median.
Uhuir.
Muscul<)-si)ii'al.
CIRCUMFLEX.
673
"Fig. 381. — Cutnneous Nerves of
Risilit Upper E.\tremit3^ Ante-
rior View.
^io'"
The branches given off below the clavicle, are derived from the three cords
of the brachial plexus, in the following manner :—
From the outer cord^ arises the external of the two anterior thoracic nerves,
the musculo-cutaneous nerve, and the outer head of the median.
From the inner cord^ arises the internal of the two anterior thoracic nerves,
the internal cutaneous, the lesser internal cutaneous (nerve of Wrisberg), the
ulnar and inner head of the median.
From the jyosttrior cord^ arise the three subscapular nerves; and the cord then
divides into the musculo-spiral and circumflex nerves.
The Anterior Thoracic Nerves (Fig. 383), two in number, supply the
Pectoral muscles.
The external^ or superficial branch, the larger of the two, arises from the
outer cord of the brachial plexus, passes inwards, across the axillary artery and
vein, and is distributed to the under surface of
the Pectoralis major. It sends down a communi-
cating filament to join the internal branch.
The internal^ or deep branch, arises from the
inner cord, and passes upwards between the
axillary artery and vein (sometimes perforates
the vein), and joins with the filament from the
superficial branch. From the loop thus formed,
branches are distributed to the under surface
of the Pectoralis minor and major muscles.
The Subscapular Nerves, three in number,
supply the Subscapularife, Teres major, and
Latissimus dorsi muscles.
The upper subscapular nerve, the smallest, enters
the upper part of the Subscapularis muscle.
The loiuer subscapular nerve enters the axil-
lary border of the Subscapularis, and terminates
in the Teres major. The latter muscle is some-
times supplied by a separate branch.
The long su.bscapularj the largest of the three,
descends along the lower border of the subscapu-
laris to the Latissimus dorsi, through which it
may be traced as far as its lower border.
The Circumflex Nerve (Fig. 384) supplies
some of the muscles, and the integument of the
shoulder, and the shoulder -joint. It arises from
the posterior cord of the brachial plexus, in com-
mon with the musculo-spiral nerve. It passes
down behind the axillary artery, and in front of
the Subscapularis; and, at the lower border of
that muscle, passes backwards, and divides into
two branches.
The upper branch winds round the neck of the
humerus, beneath the Deltoid, with the posterior
circumflex vessels, as far as the anterior border of
that muscle, supplying it, and giving off cutane-
ous branches, which pierce it to ramify in the
integument covering its lower part.
The lower branch, at its origin, distributes
filaments to the Teres minor and back part of
the Deltoid muscles. Upon the filament to the
former muscle a gangliform enlargement usually
exists. The nerve then pierces the deep fascia,
and supplies the integument over the lower two-
43
^^l
G74
SPINAL NERVES.
rior View.
thirds of the posterior surface of the Deltoid, as well as that covering the long
head of the Triceps.
The circumflex nerve, before its division^ gives off' an articular filament, which
enters the shoulder -joint below the Subscapularis.
The MuscuLO-cuTANEOUS Nerve (Fig. 383) (external cutaneous, 'perforans
Gasserii) supplies some of the muscles of the arm, and the integument of the
forearm. It arises from the outer cord of the brachial plexus opposite the lower
border of the Pectoralis minor. It then perforates the Coraco-brachialis muscle,
and passes obliquely between the Biceps and Brachialis anticus, to the outer
side of the arm, a little above the elbow, where it perforates the deep fascia and
becomes cutaneous. This nerve, in its course
Fig. 382.— Cutaneous Nerves of through the arm, supplies the Coraco-brachialis,
Riglit Upper Extremity. Poste- Biceps, and Brachialis anticus muscles, besides
sending some filaments to the el Dow-joint and
humerus.
The cutaneous portion of the nerve passes be-
hind the median cephalic vein, and divides oppo-
site the elbow-joint, into an anterior and a poste-
rior branch.
The anterior branch descends along- the radial
border of the forearm to the wrist. It is placed
in front of the radial artery, and, piercing the
deep fascia, accompanies that vessel to the back
of the wrist. It communicates with a branch
from the radial nerve, and the palmar cutaneous
branch of the median, and distributes filaments
to the integument of the ball of the thumb.
The posterior branch is given off' about the mid- ,
die of the forearm, and passes downwards, along
the back part of its radial side to the wrist. It
supplies the integument of the loAver third of the
forearm, communicating with the radial nerve,
aud the external cutaneous branch of the mus-
culo-spiral.
The Interistal Cutaneous Nerve (Fig. 383)
is one of the smallest branches of the brachial
plexus. It arises from the inner cord, in common
with the ulnar and internal head of the median,
and, at its commencement, is placed on the inner
side of the brachial artery. It passes down the
inner side of the arm, pierces the deep fascia with
the basilic vein, about the middle of the limb,
and, becoming cutaneous, divides into two
branches.
This nerve gives off, near the axilla, a cuta-
neous filament, which pierces the fascia, and
supplies the integument covering the Biceps
muscle, nearly as far as the elbow. This filament
lies a little external to the common trunk, from
which' it arises.
The anterior branchy the larger of the two,
passes usually in front of, but occasionally behind,
the median basilic vein. It then descends on the
anterior surface of the ulnar side of the forearm,
distributing filaments to the integument as far as
the wrist, and communicating with a cutaneous
branch of the ulnar nerve.
MEDIAN. 675
The posterior hranch passes obliquely downwards on the inner side of the basi-
lic vein, winds over the internal condyle of the humerus to the back of the fore-
arm, and descends, on the posterior surface of its ulnar side, to a little below
the middle, distributing filaments to the integument. It anastomoses above the
elbow, with the lesser internal cutaneous, and above the wrist, with the dorsal
branch of the ulnar nerve (Swan).
The Lesser Internal Cutaneous Nerve (nerve of Wrisberg) (Fig. 383) is
distributed to the integument on the inner side of the arm. It is the smallest
of the branches of the brachial plexus, and usually arises from the inner cord,
with the internal cutaneous and ulnar nerves. It passes through the axillary
space, at first lying behind, and then on the inner side of the axillary vein, and
communicates with the intercosto-humeral nerve. It then descends along the
inner side of the brachial artery, to the middle of the arm, where it pierces the
deep fascia, and is distributed to the integument of the back part of the lower
third of the arm, extending as far as the elbow, where some filaments are lost
in the integuments in front of the inner condyle, and others over the olecranon.
It communicates with the inner branch of the internal cutaneous nerve.
In some cases the nerve of Wrisberg and intercosto-humeral are connected
by two or three filaments, which form a plexus at the back part of the axilla.
In other cases, the intercosto-humeral is of large size, and takes the place of the
nerve of Wrisberg, receiving merely a filament of communication from the
brachial plexus, which represents the latter nerve. In other cases, this filament
is wanting, the place of the nerve of Wrisberg being supplied entirely from the
intercosto-humeral.
The Median Nerve (Fig. 383) has received its name from the course it takes
along the middle of the arm and forearm to the hand, lying between the ulnar
and the musculo-spiral and radial nerves. It arises by two roots, one from the
•outer, and one frona the inner cord of the brachial plexus ; these embrace the
lower part of the axillary artery, uniting either in front or on the outer side of
that vessel. , As it descends through the arm, it lies at first on the outer side of
the brachial artery, crosses that vessel in the middle of its course, usually in
front, but occasionally behind it, and lies on its inner side to the bend of the
elbow, where it is placed beneath the bicipital fascia, and is separated from the
elbow-joint by the Brachialis anticus. In the forearon^ it passes between the two
heads of the Pronator radii teres, and descends beneath the Flexor sublimis, to
within two inches above the annular ligament, where it becomes more superfi-
cial, lying between the Flexor sublimis and Flexor carpi radialis, beneath, or
rather to the ulnar side of the tendon of the Palmaris longus, covered by the in-
tegument and fascia. It then passes beneath the annular ligament into the hand.
Branches. No branches are given off from the median nerve in the arm. In
the forearm its branches are, muscular, anterior interosseous, and palmar cuta-
neous.
The muscular branches supply all the superficial muscles on the front of the
forearm, except the Flexor carpi ulnaris. These branches are derived from the
nerve near the elbow. The branch furnished to the Pronator radii teres often
arises above the joint.
The anterior interosseous supplies the deep muscles on the front of the fore-
arm, except the Flexor carpi ulnaris and inner half of the Flexor profundus
digitorum. It accompanies the anterior interosseous artery along the inter-
osseous membrane, in the interval between the Flexor longus pollicis and Flexor
profundus digitorum muscles, both of which it supplies, and terminates below
in the Pronator quadratus.
The palmar cutaneous hranch arises from the median nerve at the lower part
of the forearm. It pierces the fascia above the annular ligament, and divides
into two branches : of which the outer supplies the skin over the ball of the
thumb, and communicates with the external cutaneous nerve; and the inner
supplies the integument of the palm of the hand, anastomosing with the cuta-
676
SPINAL NERVES,
Fio-. 383.— Nerves of the Left Upper Extremity.
Hociemn 7
\ liter/ or T^/iomelo
T/i/£maT
'Anterior Thoraclo
11 sen To Spiral
in fer/or
ULNAR. 677
neons branch of the ulnar. Both nerves cross the annular ligament previous
to their distribution.
In the palm of the hand^ the median nerve is covered bj the integument and
palmar fascia, and rests upon the tendons of the Flexor muscles. In this situa-
tion it becomes enlarged, somewhat flattened, of reddish color, and divides into
two branches. Of these, the exfe?'7za / supplies a muscular branch to some of the
muscles of the thumb, and digital branches to the thum^b and index finger ; the
internal branch supplying digital branches to the contiguous sides of the index
and middle, and of the middle and ring fingers.
The branch to the muscles of the thumb is a short nerve, which subdivides to
supply the Abductor, Opponens, and outer head of the Flexor brevis poUicis
muscles ; remaining muscles of this group being supplied by the ulnar nerve.
The digital branches are five in number. The first and second pass along the
borders of the thumb, the external branch communicating with branches of the
radial nerve. The third passes along the radial side of the index finger, and
supplies the first Lumbricalis muscle. The fourth subdivides to supply the
adjacent sides of the index and middle fingers, and sends a branch to the second
Lumbricalis muscle. The fifth supplies the adjacent sides of the middle and
ring fingers, and communicates with a branch from the ulnar nerve.
Each digital nerve, opposite the base of the first phalanx, gives off a dorsal
branch, which joins the dorsal digital nerve, and runs along the side of the
dorsum of the finger, ending in the integument over the last phalanx. At the
end of the finger, the digital nerve divides into a palmar and a dorsal branch ;
the former of which supplies the extremity of the finger, and the latter ramifies
round and beneath the nail. The digital nerves, as they run along the fingers,
are placed superficial to the digital arteries.
The Ulnar Nerve (Fig. 383) is placed along the inner or ulnar side of the
upper limb, and is distributed to the muscles and integument of the fore-arm
and hand. It is smaller than the median, behind which it is placed, diverging
from it in its course down the arm. It arises from the inner cord of the brachial
plexus, in common with the inner head of the median and the internal cutaneous
nerve. At its commencement, it lies at the inner side of the axillary artery,
and holds the same relation with the brachial artery to the middle of the arm.
From this point it runs obliquely across the internal head of the Triceps, pierces
the internal intermuscular septum, and descends to the groove between the
internal condyle and olecranon, accompanied by the inferior profunda artery.
At the elbow^ it rests upon the back of the inner condyle, and passes into the
fore-arm between the two heads of the Flexor carpi ulnaris. In the fore-arm^
it descends in a perfectly straight course along its ulnar side, lying upon the
Flexor profundus digitorum, its upper half being covered by the Flexor carpi
ulnaris, its lower half lying on the outer side of the muscle, covered by the
integument and fascia. The ulnar artery, in the upper third of its course, is
separated from the ulnar nerve by a considerable interval ; but in the rest of its
extent, the nerve lies to its inner side. At the wrist^ the ulnar nerve crosses
the annular ligament on the outer side of the pisiform bone, a little behind the
ulnar artery, and immediately beyond this bone divides into two branches,
superficial and deep palmar.
The branches of the ulnar nerve are : —
Articular (elbow).
Muscular.
In fore-arm -{ Cutaneous. T Ti 1 i Superficial palmar.
Dorsal cutaneous. | Deep palmar.
Articular (wrist).
The articular branches distributed to the elbow -joint consist of several small
filaments. They arise from the nerve as it lies in the groove between the inner
condyle and olecranon.
678
SPINAL NERVES.
The muscular branches are two in number, one supplying tlie Flexor carpi
ulnaris, the other, the inner half of the Flexor profundus digitorum. They
arise from the trunk of the nerve near the elbow.
The cutaneous hranch arises from the ulnar nerve about the middle of the
fore-arm, ?.nd divides into a superficial and deep branch.
The superficial branch (frequently absent) pierces the deep fascia near the
wrist, and is distributed to the integument, communicating with a branch of the
internal cutaneous nerve.
The deep branch lies on the ulnar artery, which it accompanies to the hand,
some filaments entwining
Fig. 384. — The Suprascapular, Circumflex, and Musculo-
Spiral Nerves.
S^iiprctScajJu'ai
■ Circumflex
round the vessel, which end
in the integument of the
palm, communicating with
branches of the median
nerve.
The dorsal cutaneous hranch
arises about two inches above
the wrist; it passes back-
wards beneath the Flexor
carpi ulnaris, perforates the
deep fascia, and running
along the ulnar side of the
wrist and hand, supplies the
inner side of the little finger,
and the adjoining sides of
the little and ring fingers ;
it also sends a communicating
filament to that branch of,
the radial nerve which sup-
plies the adjoining sides of
the middle and ring fingers.
The articular filaments to
the wrist are also supplied by
the ulnar nerve.
The superficial p a Im a r
hranch supplies the Palmaris
brevis, and the integument
on the inner side of the hand,
and terminates in two digital
branches, which are distri-
buted, one to the ulnar side
of the little finger, the other
to the adjoining sides of the
little and ring fingers, the
latter communicating with a
branch from the median.
The deep palmar hranch
passes between the Abductor
and Flexor brevis minimi
digiti muscles, and follows
the course of the deep pal-
mar arch beneath the flexor
tendons. At i1s origin, it
supplies the muscles of the
little finger. As it crosses
the deep part of the liand, it
sends two branches to each
MUSCULO-SPIRAL. G79
interosseous space, one for the Dorsal and one for tlie Palmar interosseous
muscle, the branches to the second and third Palmar iuterossei supplying fila-
ments to the two inner Lumbricales muscles. At its ternination between the
thumb and index finger, it supplies the Adductor pollicis and the inner head of
the Flexor brevis pollicis.
The Musculo-Spiral Nerve (Fig. 384), the largest branch of the brachial
plexus, supplies the muscles of the back part of the arm and fore-arm, and the
integument of the same parts, as well as that of the hand. It arises from the
posterior cord of the brachial plexus by a common trunk with the circumflex
nerve. At its commencement it is placed behind the axillary and upper part
of the brachial arteries, passing down in front of the tendons of the Latissimus
dorsi and Teres major. It winds round the humerus in the spiral groove with
the superior profunda artery, passing from the inner to the outer side of the
bone, beneath the Triceps muscle. At the outer side of the arm, it descends
between the Brachialis anticus and Supinator longus to the front of the external
condyle, where it divides into the radial and posterior interosseous nerves.
Tlie branches of the musculo-spiral nerve are : — •
Muscular. Eadial.
Cutaneous. Posterior interosseou.s.
The muscular hranches are divided into internal, posterior, and external ; they
supply the Triceps, Anconeus, Supinator longus. Extensor carpi radialis longior,
and brachialis anticus. These bran-ches ' are derived from the nerve, at the
inner side, back part, and outer side of the arm.
The internal muscular branches supply the inner and middle heads of the
Triceps muscle. That to the inner head of the Triceps is a long, slender fila-
ment, which lies close to the ulnar nerve, as far as the lower third of the arm.
The posterior muscular branch, of large size, arises from the nerve in the
groove between the Triceps and the humerus. It divides into branches which
supply the outer head of the Triceps and Aconeus muscles. The branch for
the latter muscle is a long, slender filament, which descends in the substance
of the Triceps to the Aconeus in the same course with the posterior articular
branch from the superior profunda artery.
The external muscular branches su.pply the Supinator longus. Extensor carpi
radialis longior, and, usually, the Brachialis anticus.
The cutaneous hranches are three in number, one internal and two external.
The internal cutaneous branch arises in the axillary space, with the inner
muscular branch. It is of small size, and passes through the axilla to the inner
side of the arm, supplying the integument on its posterior aspect nearly as far
as the olecranon.
The two external cutaneous branches perforate the outer head of the Triceps,
at its attachment to thehumerns. The upper and smaller one follows the course
of the cephalic vein to the front of the elbow, supplying the integument of the
lower half of the upper arm on its anterior aspect. The lower branch pierces
the deep fascia below the insertion of the Deltoid, and passes clown along the
outer side of the arm and elbow, and along the back part of the radial side of
the fore-arm to the wrist, supplying the integument in its course, and joining,
near its termination, with a branch of the external cutaneous nerve.
The radial nerve passes along the front of the radial side of the forearm, to
the commencement of its lower third. It lies at first a little to the outer side
of the radial artery, concealed beneath the Supinator longus. In the middle
third of the fore-arm, it lies beneath the same muscle, in close relation with the
outer side of the artery. It quits the artery about three inches above the wrist,
passes beneath the tendon of the Supinator longus, and, piercing the deep fascia
at the outer border of the fore-arm, divides into two branches.
The external branch, the smaller of the two, supplies the integument of the
680 SPINAL NERVES.
radial side and ball of tlie tliumb, joining witii the posterior brancli of tbe ex-
ternal cutaneous nerve.
The internal branch communicates, above the wrist, with a branch from the
external cutaneous, and, on the back of tlie hand, forms an arch with the dorsal
branch of the ulnar nerve. It then divides into four digital nerves, which are
distributed as follows : the first supplies the ulnar side of the thumb ; the
second, the radial side of the index finger; the third, the adjoining sides of the
index and middle fingers; and the fourth, the adjacent borders of the middle
and ring fingers. The latter nerve communicates with a filament from the
dorsal branch of the nlnar nerve.
The posterior interosseous nerve pierces the Supinator brevis, winds to the
back of the fore-arm, in the substance of that mnscle, and, emerging from its
lower border, passes down between the superficial and deep layer of muscles,
to the middle of the fore-arm. Considerably diminished in size, it descends on
the interosseous membrane, beneath the Extensor secundi internodii pollicis, to
the back of the carpus, where it presents a gangliform enlargement from which
filaments are distributed to the ligaments and articulations of the carpus. It
supplies all the muscles of the radial and posterior brachial regions, excepting
the Anconeus, Supinator longus, and Extensor carpi radialis longior.
DoESAL Nerves.
The Dorsal Nerves are twelve in number on each side. The first appears
between the first and second dorsal vertebras, and the last between the last
dorsal and first lumbar.
The roots of origin of the dorsal nerves are few in number, of small size, and
vary but slightly from the second to the last. Both roots are very slender ; the
posterior roots only slightly exceeding the anterior in thickness. These roots
gradually increase in length from above downwards, and remain in contact with
the spinal cord for a distance eqnal to the height of, at least, two vertebras, in
the lower part of the dorsal region. They then join in the intervertebral fora-
men, and, at their exit, divide into two branches, a posterior (dorsal), and an
anterior (intercostal), branch.
The first and last dorsal nerves are peculiar in several respects (see page 682).
The posterior hranches of the dorsal nerves^ which are smaller than the inter-
costal, pass backwards between the transverse processes, and divide into external
and internal branches.
The external brandies increase in size from above downwards. They pass
through the Longissimus dorsi, corresponding to the cellular interval between
it and the Sacro-lumbalis, and supply those muscles, as well as their continua-
tions upwards to the head, and the Levatores costarum ; the five or six lower
nerves also give off" cutaneous filaments.
The internal hranches of the six upper nerves pass inwards to the interval
between the Multifidus spinas, and Semispinalis dorsi muscles, which they
supply; and then, piercing the origin of the Rhomboidei and Trapezius, become
cutaneous by the side of the spinous processes. The internal branches of the
six lower nerves are distributed to the Multifidus spinse, without giving off any
cutaneous filaments.
The cutaneous hranches of the dorsal nerves are twelve m number, the six
upper being derived from the internal branches, and the six lower from the
external branches. Tlie former pierce the Rhomboid and Trapezius muscles,
close to 1hc spinous processes, and ramify in the integument. They arc fre-
quently furnished with gangliform enlargements. The six lower culaneous
branches pierce the Serralus posticus inferior, and Latissimus dorsi, in a line
with the angles of the ribs.
INTERCOSTAL. 681
Intercostal Nerves.
Tlie Intercostal Nerves (anterior brandies of the dorsal nerves) are twelve in
number on each side. Thej are distributed to the parietes of the thorax and
abdomen, separately from each other, without being joined in a plexus; in
which respect they differ from the other spinal nerves. Each nerve is connected
with the adjoining ganglia of the sympathetic by one or two filaments. The
intercostal nerves may be divided into two sets, from the difference they pre-
sent in their distribution. The six upper, with the exception of the first, are
limited in their distribution to the parietes of the chest. The six lower supply
the parietes of the chest and abdomen.
The Upper Intercostal Nerves pass forwards in the intercostal spaces with the
intercostal vessels, being situated below them. At the back of the chest they
lie between the pleura and the External intercostal muscle, but are soon placed
between the two planes of intercostal muscles as far as the costal cartilages,
where they lie between the pleura and the Internal intercostal muscles. Near
the sternum, they cross the internal mammary artery, and Triangularis sterni,
pierce the Internal intercostal and Pectoralis major muscles, and supply the
integument of the mamma and front of the chest, forming the anterior cutaneous
nerves of the thorax; the branch from the second nerve becoming joined with
the clavicular nerve.
Branches. Numerous slender muscular filaments supply the Intercostal and
Triangularis sterni muscles. Some of these branches, at the front of the chest,
cross the costal cartilages from one to another intercostal space.
Lateral cutaneous nerves. These are derived from the intercostal nerves, mid-
way between the vertebrae and sternum ; they pierce the External intercostal
and Serratus magnus muscles, and divide into two branches, anterior and
posterior.
The anterior branches are reflected forwards to the side and the fore part of the
chest, supplying the integument of the chest and mamma, and the upper digita-
tions of the External oblique.
The posterior branches are reflected backwards, to supply the integument over
the scapula and over the Latissimus dorsi.
The first intercostal nerve has no lateral cutaneous branch. The lateral cuta-
neous branch of the second intercostal nerve is of large size, and named, from its
origin and distribution, the intercosto- humeral nerve (Fig. 383). It pierces the
External intercostal muscle, crosses the axilla to the inner side of the arm, and
joins with a filament from the nerve of Wrisberg. It then pierces the fascia,
and supplies the skin of the upper half of the inner and back part of the arm,
communicating with the internal cutaneous branch of the musculo-spiral nerve.
The size of this nerve is in inverse proportion to the size of the other cutaneous
nerves, especially the nerve of Wrisberg. A second intercosto-humeral nerve
is frequently given off from the third intercostal. It supplies filaments to the
arm-pit and inner side of the arm.
The Loioer Intercostal Nerves (excepting the last) have the same arrangement
as the upper ones as far as the anterior extremities of the intercostal spaces,
where they pass behind the costal cartilages, and between the Internal oblique
and Transversalis muscles, to the sheath of the Rectus, which they perforate.
They supply the Rectus muscle, and terminate in branches which become subcu-
taneous near the linea alba. These branches, which are named the anterior cuta-
neous nerves of the abdomen, supply the integument of the front of the belly : they
are directed outwards as far as the lateral cutaneous nerves. The lower inter-
costal nerves supply the Intercostal and Abdominal muscles, and, about the
middle of their course, give off lateral cutaneous branches, which pierce the
External intercostal and External oblique muscles, and are distributed to the
integument of the abdomen, the anterior branches passing nearly as far for-
682 SPINAL NERVES.
wards as the margin of tlie Rectus ; the posterior brandies passing to supply
the skin over the Latissinius clorsi, where they join tlie dorsal cutaneous nerves.
Peculiar Dorsal Nerves.
First dorsal nerve. Its roots of origin are similar to those of a cervical nerve.
l\s posterior or dorsal hranch resembles, in its mode of distribution, the dorsal
branches of the cervical nerves. Its anterior hranch enters almost wholly into
the formation of the brachial plexus, giving off, before it leaves the thorax, a small
intercostal branch, which runs along the first intercostal space, and terminates
on the front of the chest, by forming the first anterior cutaneous nerve of the
thorax. The first intercostal nerve gives off' no lateral cutaneous branch.
The last dorsal is larger than the other dorsal nerves. Its anterior branch
runs along the lower border of the last rib in front of the Quadratus lumborum,
perforates the aponeurosis of the Transversalis, and passes forwards between it
and the Internal oblique, to be distributed in the same manner as the preceding
nerves. It communicates with the ilio-hypogastric branch of the lumbar plexus,
and is occasionally connected with the first lumbar nerve by a slender branch,
the dorsi-lumbar nerve, which descends in the substance of the Quadratus
lumborum.
The lateral cutaneous hranch of the last dorsal is remarkable for its large size ;
it perforates the Internal and External oblique muscles, passes downwards over
the crest of the ilium, and is distributed to the integument of the front of the
hip, some of its filaments extending as low down as the trochanter major.
Lumbar Nerves.
The Lumbar Nerves are five in number on each side; the first appears be-
tween the first and second lumbar vertebr;©, and the last between the last lum-
bar and the base of the sacrum.
The roots of the lumbar nerves are the largest, and their filaments the most
numerous, of all the spinal nerves, and they are closely aggregated together
upon the lower end of the cord. The anterior roots are the smaller : but there
is not the same disproportion between them and the postei'ior roots as in the
cervical nerves. The roots of these nerves have a vertical direction, and are of
considerable length, more especially the lower ones, since the spinal cord does
not extend beyond the first lumbar vertebra. The roots become joined in the
intervertebral foramina; and the nerves, so formed, divide at their exit into two
branches, anterior and posterior.
The posterior hranches of the lumbar nerves diminish in size from above down-
wards; they pass backwards between the transverse processes, and divide into
external and internal branches.
The External branches supply the Erector spinoe and Intertransverse muscles.
From the three upper branches, cutaneous nerves are derived, which pierce the
Sacro-lumbalis and Latissimus dorsi muscles, and descend over the back part
of the crest of the ilium, to be distributed to the integument of the gluteal
region, some of the filaments passing as far as the trochanter major.
The internal branches, the smaller, pass inwards close to the articular pro-
cesses of the vertebras, and supply the Multifidus spinas and Lilerspinales
muscles.
The anterior hranrhes of the lumbar nerves increase in size from above down-
wards. At their origin, they communicate with the lumbar ganglia, of the syin-
jmthetic by long slender filaments, which accompany Ihe lumbar arteries round
the sides of the bodies of the vertebras, beneath the Psoas muscle. The nerves
])ass obliquely outwards behind the Psoas magnus, or between its fasciculi, dis-
tributing filaments to it and the Quadratus Inmboruin. The anterior branches
of the fijur upper nerves arc connected together in this situation by anastomotic
LUMBAR PLEXUS.
683
loops, and form the lumbar 'plexus. The anterior brancli of the fifth lumbar,
joined with a branch from the fourth, descends across the base of the sacrum
to join the anterior brancli of the first sacral nerve, and assist in the formation
of the sacral plexus. The cord resulting from the union of these two nerves is
called the lumho-sacral 7ierve.
Lumbar Plexus.
The Lumbar Plexus is formed by the loops of communication between the
anterior branches of the four upper lumbar nerves. The plexus is narrow
above, and occasionally connected with the last dorsal by a slender branch, the
dorsi-lumbar nerve; it is broad below, where it is joined to the sacral plexus by
the lumbo-sacral cord. It is situated in the substance of the Psoas muscle near
its posterior part, in front of the transverse processes of the lumbar vertebree.
Fig:. 385. — The Lumbar Plexus and its Branches.
The niode in which the plexus is formed is the following : The first lumbar
nerve gives oft" the ilio-hypogastric and ilio-inguinal nerves, and a communi-
cating branch to the second lumbar nerve. The second gives off the external
cutaneous and genito-crural, and a communicating branch to the third nerve.
The third nerve gives a descending filament to the fourth, and divides into two
branches which assist in forming the anterior crural and obturator nerves;
sometimes, also, it furnishes a part of the accessory obturator. The fourth
nerve completes the formation of the anterior crural, and the obturator, and
684 SPINAL NERVES.
gives off a communicating brancli to the fifth lumbar; sometimes it also
furnishes part of the accessory obturator.
The Ijranches of the lumbar plexus are the
Ilio-hypogastrio. Obturator.
Ilio-inguinal. Accessory obturator.
Geuito-crural. Anterior crural.
External cutaneous.
These branches may be divided into two groups, according to their mode of
distribution. One group, including the ilio-hypogastric, ilio-inguinal, and part
of the genito-crural nerves, supplies the lower part of the parietes of the abdo-
men; the other group, which includes the remaining nerves, supplies the fore-
part of the thigh and inner side of the leg.
The Ilio-hypogastric Nerve {superior musculo-cutaneous) arises from the
first lumbar nerve. It pierces the outer border of the Psoas muscle at its
upper part, and crosses obliquely in front of the Quadratus lumborum to the
crest of the ilium. It then perforates the Transversalis muscle at its back part,
and divides between it and the Internal oblique into two branches, iliac and
hypogastric.
The iliac hranch pierces the Internal and External oblique muscles imme-
diately above the crest of the ilium, and is distributed to the integument of
the gluteal region, behind the lateral cutaneous branch of the last dorsal nerve
(Fig. 388). The size of this nerve bears an inverse proportion to that of the
cutaneous branch of the last dorsal nerve.
The hypogastric hranch (Fig. 386) continues onwards between the Internal
oblique and Transversalis muscles. It first pierces the Internal oblique, and
near the middle line perforates the External oblique above the external abdomi-
nal ring, and is distributed to the integument covering the hypogastric region.
The Ilio -Inguinal Nerve [inferior miiscuh-cutaneous), smaller than the
preceding, arises with it from the first lumbar nerve. It pierces the outer
border of the Psoas just below the ilio-hypogastric, and, passing obliquely
across the Quadratus lumborum and Iliacus muscles, perforates the trans-
versalis, near the fore part of the crest of the ilium, and communicates with
the Ilio-hypogastric nerve between that muscle and the Internal oblique. The
nerve then pierces the Internal oblique, distributing filaments to it, and, accom-
panying the spermatic cord, escapes at the external abdominal ring, and is
distributed to the integument of the scro^tum and upper and inner part of the
thigh in the male, and to the labium in the female. The size of this nerve is
in inverse proportion to that of the ilio-hypogastric. Occasionally it is very
small, and ends by joining the ilio-hypogastric; in such cases, a branch from
the ilio-hypogastric takes the place of the ilio-inguinal, or the latter nerve may
be altogether absent.
The Genito-crural Nerve arises from the second lumbar, and by a few
fibres from the cord of communication between it and the first. It passes
obliquely through the substance of the Psoas, descends on its surface to near
Poupart's ligament, and divides into a genital and a crural branch.
The genital hranch descends on the external iliac artery, sending a few fila-
ments round that vessel ; it then pierces the fascia transversalis, and, passing
through the internal abdominal ring, descends along the back part of the
spermatic cord to the scrotum, and supplies, in the male, the Cremaster muscle.
In the female, it accompanies the round ligament, and is lost upon it.
The crural hranch passes along the inner margin of the Psoas muscle, beneath
Poupart's ligament, into the thigh, where it pierces the fiiscia lata, and is distri-
buted to the integument of the upper and anterior aspect of the thigh, communi-
cating with the middle cutaneous nerve.
A few filaments from this nerve may be 1 raced on 1o the femoral artery;
tlicy arc derived from Ihc nerve as it j^asses bcneatli i*iiiiiiai-t's ligament.
LUMBAR PLEXUS.
685
Fig. 386. — Cutaneous Nerves of Lower
Extremity. Front Yiew.
^-5 \ ^Aofjast
A
I^Uffcefi^eneas.
.Aut. Tibial
Fig. 387. — Nerves of the Lower Extremity.
Front View.
A.nterief
Crural
A.7t. ter/orDivision
■J Oitu-raiof
686 SPINAL NERVES.
The External Cutaneous Nerve arises from the second lumbar, or from
the loop between it and the third. It perforates the outer border of the Psoas
muscle about its middle, and crosses the Iliacus muscle obliquely, to the notch
immediately beneath the anterior superior spine of the ilium, where it passes
beneath Poupart's ligament into the thigh, and divides into two branches of
nearly equal size.
The anterior branch descends in an aponeurotic canal formed in the fascia
lata, becomes superficial about four inches below Poupart's ligament, and
divides into branches, which are distributed to the integument along the ante-
rior and outer part of the thigh, as far down as the knee. This nerve occasion-
ally communicates with the long saphenous nerve.
The posterior branch pierces the fascia lata, and subdivides into branches
which pass across the outer and posterior surface of the thigh, suppljdng the
integument as far as the middle of the thigh.
The Obturator Nerve supplies the Obturator externus and Adductor
muscles of the thigh, the a^rticulations of the hip and knee, and occasionally the
integument of the thigh and leg. It arises by two branches; one from the
third, the other from the fourth lumbar nerve. It descends through the inner
fibres of the Psoas muscle, and emerges from its inner border near the brim of
the pelvis; it then runs along the lateral wall of the pelvis, above the obturator
vessels, to the upper part of the obturator foramen, where it enters the thigh,
and divides into an anterior and a posterior branch separated by the Adductor
brevis muscle.
The anterior branch (Fig. 387) passes down in front of the Adductor brevis,
being covered by the Pectineus and Adductor longus ; and at the lower border
of the latter muscle, communicates with the internal cutaneous and internal
saphenous nerves, forming a kind of plexus. It then descends upon the femoral
artery, upon which it is finally distributed.
This nerve, near the obturator foramen, gives off an articular branch to the
hip-joint. Behind the Pectineus, it distributes muscular branches to the Ad-
ductor longus and Gracilis, and occasionally to the Adductor brevis and Pecti-
neus, and receives a communicating branch from the accessory obturator nerve.
Occasionally this communicating branch is continued down, as a cutaneous
branch, to the thigh and leg. This occasional cutaneous branch emerges from
the lower border of the Adductor longus, descends along the posterior margin
of the Sartorius to the inner side of the knee, where it pierces the deep fascia,
communicates with the long saphenous nerve, and is distributed to the integu-
ment of the inner side of the leg, as low down as its middle. When the branch
is small, its place is supplied by the internal cutaneous nerve.
The posterior branch of the obturator nerve pierces the Obturator externus,
and passes behind the Adductor brevis to the front of the Adductor magnus,
where it divides into numerous muscular branches, which supply the Obturator
externus, the Adductor magnus, and occasionally the Adductor brevis.
The articular branch for the knee-joint perforates the lower part of the Ad-
ductor magnus, and enters the popliteal space ; it then descends upon the pop-
liteal artery, as far as the back part of the knee-joint, where it ])crforates the
jjostcrior ligament, and is distributed to the synovial membrane. It gives fila-
ments to the artery in its course.
The Accessory Obturator Nerve (Fig. 385) is of small size, and arises
either from the obturator nerve near its origin, or by separate filaments from
the tliird and fourth lumbar nerves. It descends along tlie inner border of the
Psoas muscle, crosses tlie body of the ])ubes, and passers l)cneath the Pectineus
muscle, where it divides into numerous branches. Oik- of tlicse supplies the
Pectineus, penetrating its under surface; another is disliibutod to the hip-
joint; while a third communicates with the anterior biaiich oC the obturator
nerve. Tliis branch, when of large size, is prolonged (as already mentioned), as a
cutaneous branch, to the leg. The accessory obturator nerve is not constantly
ANTERIOR CRURAL. G87
found ; when absent, tlie hip-joint receives branches from the obturator nerve.
Occasionally it is very small, and becomes lost in the capsule of the hip-joint.
The Anterior Crural Nerve (Figs. 385, 387) is the largest branch of the
lumbar plexus. It supplies muscular branches to the Iliacus, Pectineus, and all
the muscles on the front of the thigh, excepting the Tensor vagime femoris ;
cuta.neous filaments to the front and inner side of the thigh, and to the leg and
foot ; and articular branches to the knee. It arises from the third and fourth
lumbar nerves, receiving also a fasciculus from the second. It descends through
the fibres of the Psoas muscle, emerging from it at the lower part of its outer
border ; and passes down between it and the Iliacus, and beneath Poupart's
ligament, into the thigh, where it becomes somewhat flattened, and divides into
an anterior or cutaneous, and a posterior or muscular part. Beneath Poupart's
ligament, it is separated from the femoral artery by the Psoas muscle, and lies
beneath the iliac fascia.
Within the pelvis^ the anterior crural nerve gives off from its outer side some
small branches to the Iliacils, and a branch to the femoral artery, which is dis-
tributed upon the upper part of that vessel. The origin of this branch varies ;
it occasionally arises higher than usual, or it may arise lower down in the thigh.
External to the pelvis^ the following branches are given off: —
From the Anterior Division. From the Posterior Division.
Middle cutaneous. Muscular.
Internal cutaneous. Articular.
Long saphenous.
The middle cutaneous nerve (Fig. 386) pierces the fascia lata (occasionally the
Sartorius also) about three inches below Poupart's ligament, and divides into
two branches, which descend in immediate proximity along the fore part of the
thigh, distributing numerous branches to the integument as low as the front
of the knee, where the middle cutaneous communicates with a branch of the
internal saphenous nerve. Its outer branch communicates, above, with the
crural branch of the genito-crural nerve ; and the inner branch with the internal
cutaneous nerve below. The Sartorius muscle is supplied by this or the follow-
ing nerve.
The internal cutaneous nerve passes obliquely across the upper part of the
sheath of the femoral artery, and divides in front, or at the inner side of that
vessel, into two branches, anterior and internal.
The anterior branch perforates the fascia lata at the lower third of the thigh,
and divides into two branches, one of which supplies the integument as low
down as the inner side of the knee ; the other crosses the patella to the outer
side of the joint, communicating in its course with the long saphenous nerve.
A cutaneous filament is occasionally given off" from this nerve, which accom-
panies the long saphenous vein; and it sometimes communicates with the
internal branch of the nerve.
The inner branch descends along the posterior border of the Sartorius muscle
to the knee, where it pierces the fascia lata, communicates with the long saphe-
nous nerve, and gives off several cutaneous branches. The nerve then passes
down the inner side of the leg, to the integument of which it is distributed.
This nerve, beneath the fascia lata, joins in a plexiform network, by uniting
with branches of the long saphenous and obturator nerves (Fig. 387). When
the communicating branch from the latter nerve is large, and continued to the
integument of the leg, the inner branch of the internal cutaneous is small, and
terminates at the plexus, occasionally giving off' a few cutaneous filaments.
This nerve, before subdividing, gives off' a few filaments, which pierce the
fascia lata, to supply the integument of the inner side of the thigh, accom-
panying the long saphenous vein. One of these filaments passes through the
saphenous opening ; a second becomes subcutaneous about the middle of the
thigh ; and a third pierces the fascia at its lower third.
688 SPINAL NERVES.
The long^ or internal saphejious nerve, is the largest of the cutaneous branches
of the anterior crurah It approaches the femoral artery where this vessel
passes beneath the Sartorius, and lies on its outer side, beneath the aponeurotic
covering, as far as the opening in the lo\ver part of the Adductor magnus. It
then quits the artery, and descends vertically along the inner side of the knee
beneath the Sartorius, pierces the deep fascia between the tendons of the
Sartorius and Gracilis, and becomes subcutaneous. The nerve then passes
along the inner side of the leg, accompanied by the internal saphenous vein,
descends behind the internal border of the tibia, and, at the lower third of the
leg, divides into two branches : one continues its course along the margin of
the tibia, terminating at the inner ankle ; the other passes in front of the ankle,
and is distributed to the integument along the inner side of the foot, as far as
the great toe.
Branches. The long saphenous nerve, about the middle of the thigh, gives off
a communicating branch, which joins the plexus formed by the obturator and
internal cutaneous nerves.
At the inner side of the hnee, it gives off a large branch [n. cutaneus j^atellse),
which pierces the Sartorius and fascia lata, and is distributed to the integument
in front of the patella. This nerve communicates above the knee with the
anterior branch of the internal cutaneous; below the knee, with other branches
of the long saphenous; and, on the outer side of the joint, with branches of the
middle and external cutaneous nerves, forming a plexiform network, the plexus
patellse. The cutaneous nerve of the patella is occasionally small, and terminates
by joining the internal cutaneous, which supplies its place in front of the knee.
Beloio the knee, the branches of the long saphenous nerve are distributed to
the integument of the front and inner side of the leg, communicating with the
cutaneous branches from the internal cutaneous, or obturator nerve.
The Deep Group of branches of the anterior crural nerve are muscular and
articular.
The muscular branches supply the Pectineus and all the muscles on the front
of the thigh except the Tensor vaginee femoris, which is supplied from the
superior gluteal nerve, and the Sartorius, which is supplied by filaments from
the middle or internal cutaneous nerves.
The branches to the Pectineus, usually two in number, pass inwards behind
the femoral vessels, and enter the muscle on its anterior surface.
The branch to the Rectus muscle enters its under surface high up.
The branch to the Vastus externus, of large size, follows the course of the
descending branch of the external circumflex artery, to the lower part of the
muscle. It gives off an articular filament.
The branches to the Vastus internus and Crureus enter the middle of those
muscles.
The articular branches, two in number, supply the knee-joint. One, a long
slender filament, is derived from the nerve to the Yastus externus. It pene-
trates the capsular ligament of the joint on its anterior aspect. The other is
derived from the nerve to the Vastus internus. It descends along the internal
intermuscular septum, accompanying the deep branch of the anastomotica
magna artery, pierces the capsular ligament of the joint on its inner side, and
Bupplies the synovial membrane.
The Sacral and Coccygeal Nerves.
The sacral nerves arc five in ninnl)cr on each side. Tlie four u]~)pcr ones pass
from the sacral canal, throagli the sacral foramina; the fifth throiigli the
foramen between the sacrum and coccyx.
The roots of origin of tlie upper sacral (and lumbar) nerves are the largest of
all the spinal nerves; whilst those of the lowest sacral and coccygeal nerves arc
the smallest.
SACRAL AND COCCYGEAL. 689
Tlie roots of tliese nerves are of very considerable length, heing longer than
those of any of the other spinal nerves; on account of the spinal cord not
extending beyond the first lumbar vertebra. From their great length, and the
appearance they present in connection. with the spinal canal, the roots of origin
of these nerves are called collectively the cauda equina. Each sacral and
coccygeal nerve divides into two branches, anterior and posterior.
'Vh.Q posterior sacral nerves are'small, diminish in size from above downwards,
and emerge, except the last, from the sacral canal by the posterior sacral
foramina.
The three upper ones are covered, at their exit from the sacral canal, by the
Multifidus spinae, and divide into external and internal branches.
The internal branches are small, and supply the Multifidus spinee.
The external branches communicate with one another, and with the last lumbar
and fourth sacral nerves, by means of anastomosing loops. These branches pass
outwards, to the outer surface of the great sacro-sciatic ligament, where they
form a second series of loops beneath the Gluteus maximus. Cutaneous branches
from this second series of loops, usually three in number, pierce the Gluteus
maximus : one near the posterior inferior spine of the ilium ; another opposite
the end of the sacrum ; and the third, midway between the other two. They
supply the integument over the posterior part of the gluteal region.
The two lower posterior sacral nerves are situated below the Multifidus spinse.
They are of small size, and join with each other, and with the coccygeal nerve,
so as to form loops on the back of the sacrum, filaments from which supply the
integument over the coccyx.
The coccygeal nerve divides into its anterior and posterior branch in the spinal
canal. The posterior branch is the smaller. It receives, as already mentioned,
a communicating branch from the last sacral, and is lost in the fibrous structure
on the back of the coccyx.
The anterior sacred nerves diminish in size from above downwards. The four
upper ones emerge from the anterior sacral foramina : the anterior branch of the
fifth, together with the coccygeal nerve between the sacrum and the coccyx.
All the anterior sacral nerves communicate with the sacral ganglia of the sym-
pathetic, at their exit from the sacral foramina. The first nerve, of large size,
unites with the lumbo-sacral nerve. The second equals in size the preceding,
with which it joins. The third^ about one-fourth the size of the second, unites
with the preceding nerves, to form the sacral plexus.
^\iQ fourth anterior sacral nerve sends a branch to join the sacral plexus. The
remaining portion of the nerve divides into visceral and muscular branches : and
a communicating filament descends to join the fifth sacral nerve. The visceral
branches are distributed to the viscera of the pelvis, communicating with the
sympathetic nerve. These branches ascend upon the rectum and bladder : in
the female, upon the vagina and bladder, communicating with branches of the
sympathetic to form the hypogastric plexus. The muscular branches are dis-
tributed to the Levator ani, Coccygeus, and Sphincter ani. Cutaneous filaments
arise from the latter branch, which supply the integument between the anus and
coccyx.
The fifth anterior sacral nerve, after passing from the lower end of the sacral
canal, pierces the Coccygeus muscle, and descends upon its anterior surface to
the tip of the coccyx, where it perforates that muscle, to be distributed to the
integument over the back part and sides of the coccyx. This nerve communi-
cates above with the fourth sacral, and below with the coccygeal nerve, and sujd-
plies the Coccygeus muscle.
The anterior branch of the coccygeal nerve is a delicate filament which escapes
at the termination of the sacral canal. It pierces the sacro-sciatic ligament and
Coccygeus muscle, is joined by a branch from the fifth anterior sacral, and be-
comes lost in the integument at the back part and side of the coccyx.
44:
690 SPINAL NERVES.
Sacral Plexus.
Tlie Sacral Plexus is formed by tlie lumbo-sacral, tlie anterior branches of
tlie three upper sacral nerves, and part of that of the fourth. These nerves pro-
ceed in different directions ; the upper ones obliquely downwards and outwards,
the lower one nearly horizontally, and they all unite into a single, broad, flat
cord. The sacral plexus is triangular in form, 'its base corresponding with the
exit of the nerves from the sacrum, its apex with the lower part of the great
sacro-sciatic foramen. It rests upon the anterior surface of the Pyriformis, and
is covered in front by the pelvic fascia, which separates it from the sciatic and
pudic branches of the internal iliac artery, and from the viscera of the pelvis.
The branches of the sacral plexus are :—
Muscular. Pudic.
Superior gluteal. Small sciatic.
Great sciatic.
The muscular hranches supply the Pyriformis, Obturator internus, the two
Gemelli, and the Quadratus femoris. The branch to the Pyriformis arises either
from the plexus, or from the upper sacral nerves : the branch to the Obturator
internus arises at the junction of the lumbo-sacral and first sacral nerves; it
crosses behind the spine of the ischium, and passes through the lesser sacro-
sciatic foramen to the inner surface of the Obturator internus ; the branch to
the Gemellus superior arises from the lower part of the plexus, near the pudic
nerve ; the small branch to the Gemellus inferior and Quadratas femoris also
arises from the lower part of the plexus : it passes beneath the Gemelli and
tendon of the Obturator internus, and supplies an articular branch to the hip-
joint. This branch is occasionally derived from the upper part of the great
sciatic nerve.
The SuPEEiOK Gluteal Nerve (Fig. 389) arises from the back part of the-
lumbo-sacral ; it passes from the pelvis through the great sacro-sciatic foramen
above the Pyriformis muscle, accompanied by the gluteal vessels, and divides
into a superior and an inferior branch.
The superior hrancli follows the line of origin of the Gltiteus minimus, and
supplies it and the Gluteus medius.
The inferior hrancli crosses obliquely between the Gluteus minimus and medius,
distributing filaments to both these muscles, and terminates in the Tensor vaginas
femoris, extending nearly to its lower end.
The Pudic Nerve arises from the lower part of the sacral plexus, and leaves
the pelvis, through the great sacro-sciatic foramen,, below the Pyriformis. It
then crosses the spine of the ischium, and re-enters the pelvis through the lesser
sacro-sciatic foramen. It accompanies the pudic vessels upwards and forwards
along the outer wall of the ischio-rectal fossa, being covered by the obturator
fascia, and divides into two terminal branches, the perineal nerve and the dorsal
nerve of the penis. Near its origin, it gives off the inferior hemorrhoidal nerve.
The inferior hemorrhoidal nerve is occasionally derived from the sacral
plexus. It passes across the ischio-rectal fossa, with its accompanying vessels,
towards the lower end of the rectum, and is distributed to the External sphincter
and the integument round the anus. Branches of this nerve communicate with
the inferior pudendal and superficial perineal nerves on the inner margin of the
thigh.
^\\Q perineal nerve^ the inferior and larger <jf the two terminal branches of the
pudic, is situated below the pudic artery. It accompanies the superficial peri-
neal artery in the perineum, dividing into cutaneous and muscular branches.
The cutaneous branches (superficial perineal) arc 1\vo iu number, posterior
and antc^rior. The posterinr hrancli passes to the back ]iart of the ischio-rectal
fossa, distributing filaments to the Sj^hinctcr ani and inlcgument in fnmt of the
anus, which (•ouiiininicale with the inferior lK'.iiiorrliol<lal nerve; it tlicn passes
SACRAL PLEXUS.
691
Fig. 388. — Cutaneous Nerves of Lower
Extremity. Posterior View.
Fig. 389. — Nerves of the Lower Extremity.
Posterior View.
ftluteul
Pu.
N.to OBTURATOR
ftmalf Sciatic
Com rr.itnlenti
Externttl
Popliteal ,tr
Peroneal
Communicam
J'eronet
C92 SPINAL NERVES.
forwards, witti the anterior branch, to the back of the scrotum, communicating
with the anterior branch and with the inferior pudendal. The anterior branch
passes to the fore part of the ischio-rectal fossa, in front of the preceding, and
accompanies it to the scrotum and under part of the penis. This branch gives
one or two filaments to the Levator ani.
The muscular branches are distributed to the Transversus perinei, Accelerator
urince, Erector penis, and Compressor urethrge. The nerve of the bulb supplies
the corpus spongiosum ; some of its filaments run for some distance on the sur-
face before penetrating to the interior.
The dorsal nerve of the j^enis is the superior division of the pudic nerve ; it
accompanies the pudic artery along the ramus of the ischium, and between the
two layers of the deep perineal fascia; at then pierces the suspensory ligament
of the penis, and accompanies the arteria dorsalis penis to the glans, to which
it is distributed. On the penis, this nerve gives off' a cutaneous branch, which
runs along the side of the organ; it is joined with branches of the sympathetic,
and supplies the integument of the upper surface and sides of the ]3enis and pre-
puce, giving a large branch to the corpus cavernosum.
In the female, the pudic nerve is distributed to the parts analogous to those
in the male ; its superior division terminating in the clitoris, its inferior in the
external labia and perineum.
The Small Sciatic Nerve (Fig. 389) supplies the integument of the perineum
and back part of the thigh and leg, and one muscle, the Gluteus maximus. It
is usually formed by the union of two branches, which arise from the lower part
of the sacral plexus. It issues from the pelvis below the Pyriformis muscle,
descends beneath the Gluteus maximus with the sciatic artery, and at the lower
border of that muscle passes along the back part of the thigh, beneath the fascia
lata, to the lower part of the popliteal region, where it pierces the fascia and
becomes cutaneous. It then accompanies the external saphenous vein below the
middle of the leg, its terminal filaments communicating with the external saphe-
nous nerve.
The branches of the small sciatic nerve are muscular (inferior gluteal) and
cutaneous.
The inferior gluteal consist of several large branches given off to the under
surface of the Gluteus maximus, near its lower part.
The cutaneous branches consist of two groups, internal and ascending.
The internal cutaneous branches are distributed to the skin at the upper and
inner side of the thigh, on its posterior aspect. One branch, longer than the
rest, the inferior pudendal^ curves forward below the tuber ischii, pierces the
fascia lata on the outer side of the ramus of the ischium, and is distributed to
the integument of the scrotum, communicating with the superficial perineal
nerve.
The ascending cutaneous branches consist of two or three filaments, wliich turn
upwards round the lower border of the Gluteus maximus, to supply the integu-
ment covering its surface. One or two filaments occasionally descend along the
outer side of the thigh, supplying the integument as far as the middle of that
regi on .
Two or three brandies are given off' from the lesser sciatic nerve as it descends
beneath, the fascia of tlie thigh ; they supply the integument of the back part
of the thigh, popliteal region, and upper part of the leg.
The Great Sciatic Nerve (Fig. 389) supplies nearly the whole of the integu-
ment of the leg, the muscles of the back of the thigh, and those of the leg and
foot. It is the largest nervous cord in the body, measuring three-quarters of an
inch in breadth, and is the continuation of the lower part of the sacral ]~)lexus.
It passes out of the pelvis through the grcjit sacro-sciatic foramen, below the
Pyriformis muscle. It descends between tlm trochanter major and tuberosity
of the ischium along the back part of the thigli to about its lower third, where
it divides into two large branches, the internal and external popliteal nerves.
GREAT SCIATIC. 693
Tliis division may tal<;e place at any point between tlie sacral plexus and the
lower tliird of tlie tliigli. AVben tlie division occnrs at the plexus, the two
nerves descend together, side by side; or they may be separated, at their com-
mencement, by the interposition of part or the whole of the Pyriformis muscle.
As the nerve descends along the back of the thigh, it rests at first upon the
External rotator muscles, together with the small sciatic nerve and artery, being
covered by the Grluteus maximus; lower down, it lies upon the Adductor magnus,
and is covered by the long head of the Biceps.
The branches of the nerve, before its division, are articular and muscular.
The articular branches arise from the upper part of the nerve; they supply
the hip-joint, perforating its fibrous capsule posteriorly. ■ These branches are
sometimes derived from the sacral plexus.
The muscular branches are distributed to the Flexors of the leg: viz., the
Biceps, Semitendinosus, and Semimembranosus, and a branch to the Adductor
magnus. These branches are given off beneath the Biceps muscle.
The Internal Popliteal Nerve^ the larger of the two terminal branches of the
great sciatic, descends along the back part of the thigh, through the middle of
the popliteal space, to the lower part of the Popliteus muscle, where it passes
with the artery beneath the arch of the Soleus, and becomes the posterior tibial.
It lies at first very superficial, and at the outer side of the popliteal vessels ;
opposite the knee-joint, it is in close relation with the vessels, and crosses the
artery to its inner side.
The branches of this nerve are articular, muscular, and a cutaneous branch,
the external or short saphenous nerve.
The articular branches^ usually three in number, supply the knee-joint: two
of these branches accompany the superior and inferior internal articular arteries ;
and a third, the azygos.
The muscular branches, four or five in number, arise from the nerve as it lies
between the two heads of the Gastrocnemius muscle ; they supply that muscle,
the Plantaris, Soleus, and Popliteus. The nerves which supply the Popliteus
turn round its lower border and are distributed to its deep surface.
The external or short saphenous nerve (Fig. 388) descends between the two
heads of the Gastrocnemius muscle, and, about the middle of the back of the
leg, pierces the deep fascia, and receives a communicating branch {communicans
peronei) from the external popliteal nerve. The nerve then continues its course
down the leg near the outer margin of the tendo Achillis, in company with the
external saphenous vein, winds round the outer malleolus, and is distributed to
the integument along the outer side of the foot and little toe, communicating on
the dorsum of the foot with the muscu.lo-cutaneous nerve.
The posterior tibial nerve (Fig. 389) commences at the lower border of the Pop-
liteus muscle, and passes along the back part of the leg with the posterior tibial
vessels to the interval between the inner mxalleolus and the heel, where it divides
into the external and internal plantar nerves. It lies upon the deep muscles of
the leg, and is covered by the deep fascia, the superficial muscles, and integu-
ment. In the upper part of its course, it lies to the inner side of the posterior
tibial artery; but it soon crosses that vessel, and lies to its outer side as far as
the ankle. In the lower third of the leg, it is placed parallel with the inner
margin of the tendo Achillis.
The branches of the posterior tibial nerve are muscular and plantar-cutaneous.
The muscular branches arise either separately or by a common, trunk from the
upper part of the nerve. They supply the Tibialis posticus. Flexor longus digi-
torum, and Flexor longus pollicis muscles ; the branch to the latter muscle
accompanying the peroneal artery.
The plantar cutaneous branch perforates the internal annular ligament, and
supplies the integument of the heel and inner side of the sole of the foot.
The internal plantar nerve (Fig. 390), the larger of the two terminal branches
of the posterior tibial, accompanies the internal plantar artery along the inner
694
SPINAL NERVES.
Fiff. 390.— The Plantar Nerves.
[ntema f
side of tlic foot. From its origin at tlie inner ankle it jiasses forwards between
tlie Abductor pollicis and Flexor brevis digitorum, divides opposite the bases of
the metatarsal bones into four digital branches,
and communicates with the external plantar
nerve.
Branches. In its course, the internal plan-
tar nerve gives off cutaneous branches which
pierce the plantar fascia, and supply the in-
tegument of the sole of the foot; muscular
hranches^ which supply the Abductor pollicis
and Flexor brevis digitorum; articular
branches to the articulations of the tarsus and
metatarsus; and four digital branches. These
pierce the plantar fascia in the clefts between
the toes, and are distributed in the following
manner : The first supplies the inner border
of the great toe, and sends a filament to the
Flexor brevis pollicis muscle; the seco7id
bifurcates, to suppl}^ the adjacent sides of the
great and second toes, sending a filament to
the first Lumbricalis muscle ; the third digital
branch supplies the adjacent sides of the
second and third toes, and the second Lumbri-
calis muscle ; the fourth supplies the corre-
sponding sides of the third and fourth toes,
and receives a communicating branch from
the external plantar nerve. It will be ob-
served, that the distribution of these branches
is precisely similar to that of the median-
nerve in the hand. Each digital nerve gives
off cutaneous and articular filaments ; and
opposite the last phalanx sends a dorsal
branch, which supplies the structure round the nail, the continuation of the nerve
being distributed to the ball of the toe.
. The external plantar nerve^ the smaller of the two, completes the nervous
supply to the structures of the foot, being distributed to the little toe and one-
half of the fourth, as well as to most of the deep muscles, its distribution being-
similar to that of the ulnar in the hand. It passes obliquely forwards with the
external plantar artery to the outer side of the foot, lying between the Flexor
brevis digitorum and Flexor accessorius; and, in the interval between the former
muscle and Abductor minimi digiti, divides into a superficial and a deep branch.
Before its division, it supplies the Flexor accessorius and Abductor minimi
digiti.
The superficial branch separates into two digital nerves: one, the smaller of
the two, supplies the outer side of the little toe, the Flexor brevis minimi digiti,
and the two interosseous muscles of the fourth metatarsal space ; the other, and
larger digital branch, supplies the adjoining sides of the fourth and fifth toes,
and communicates with the internal plantar nerve.
The deep or muscular branch accompanies the external ]')lantar artery into the
dcc|) part of the sole of the foot, beneath the tendons of the Flexor muscles
and Adductor pollicis, and supplies all the interossei (except those in the fourth
metatarsal space), the two outer Luuibricales, the Adductor pollicis, and the
Transversus pedis.
The External Popliteal or Peroneal Nerve (Fig, 389), about one-half the si/o
of the internal [lopliteal, descends obliquely along the outer side of the pojiliteal
space to the fibula, f;1f)se to the margin of the Bicc]")s muscle. It is easily felt
beneath llie skin behind the licad dI' the fibula, at the inucr side of the tendon
CUTANEOUS NERVES OF FOOT. 695
of tTie Biceps, About an incli below the bead of the fibula it pierces the origin
of the Peroneus longus, and divides beneath that muscle into the anterior tibial
and musculo-cutaneous nerves.
The hranches of the peroneal nerve, previous to its division, are articular and
cutaneous.
The articular branches^ two in number, accompany the superior and inferior
external articular arteries to the outer side of the knee. The upper one occa-
sionally arises from the great sciatic nerve before its bifurcation. A third (recur-
rent) articular nerve is given off at the point of division of the peroneal nerve;
it ascends with the tibial recurrent artery through the Tibialis anticus muscle
to the front of the knee, which it supplies.
The cutaneous branches^ two or three in number, supply the integument along
the back part and outer side of the leg, as far as its middle or lower part; one
of these, larger than the rest, the communicans peronei^ arises near the head of
the fibula, crosses the external head of the Gastrocnemius to the middle of the
leg, and joins with the external saphenous. This nerve occasionally exists as a
separate branch, which is continued down as far as the heel.
The Anterior Tihial Nerve (Fig. 387) commences at the bifurcation of the
peroneal nerve, between the fibula and upper part of the Peroneous longus,
passes obliquely forwards beneath the Extensor longus digitorum to the fore
part of the interosseous membrane, and reaches the outer side of the anterior
tibial artery above the middle of the leg; it then descends with the artery to
the front of the ankle-joint, where it divides into an external and an internal
branch. This nerve lies at first on the outer side of the anterior tibial artery,
then in front of it, and again at its outer side at the ankle-joint.
The branches of the anterior tibial nerve, in its course through the leg, are
the muscular nerves to the Tibialis anticus. Extensor longus digitorum, Peroneus
tertius, and Extensor proprius poUicis muscles.
The external or tarsal branch of the anterior tibial passes outwards across the
tarsus, beneath the Extensor brevis digitorum, and having become ganglionic,
like the posterior interosseous nerve at the wrist, supplies the Extensor brevis
digitorum and the articulations of the tarsus and metatarsus.
The internal branchy the continuation of the nerve, accompanies the dorsalis
pedis artery along the inner side of the dorsum of the foot, and, at the first in-
terosseous space, divides into two branches, which supply the adjacent sides of
the great and second toes, communicating with the internal division of the
musculo-cutaneous nerve.
The Musculo-cutaneous Nerve (Fig. 387) supplies the muscles on the fibular
side of the leg, and the integument of the dorsum of the foot. It passes for-
wards between the Peronei muscles and the Extensor longus digitorum, pierces
the deep fascia at the lower third of the leg, on its front and outer side, and
divides into two branches. This nerve, in its course between the muscles, gives
off' muscular branches to the Peroneus longus and brevis, and cutaneous fila-
ments to the integument of the lower part of the leg.
The internal branch of the musculo-cutaneous nerve passes in front of the
ankle-joint, and along the dorsum of the foot, supplying the inner side of the
great toe, and the adjoining sides of the second and third toes. It also supplies
the integument of the inner ankle and inner side of the foot, communicating
with the internal saphenous nerve, and joins with the anterior tibial nerve,
between the great and second toes.
The external branchy the larger, passes along the outer side of the dorsum of
the foot, to be distributed to the adjoining sides of the third, fourth, and fifth
toes. It also supplies the integument of the outer ankle and outer side of the
foot, communicating with the short saphenous nerve.
The distribution of these branches of the musculo-cutaneous nerve will be
found to vary; together, they supply all the toes excepting the outer side of
the little toe, and the adjoining sides of the great and second toes.
The Sympathetic Nerve.
The Sympatlietic Nerve is so called from the opinion entertained that tlirougli
it is produced a syni'pathy between the affections of distant organs. It consists
of a series of ganglia, connected together by intervening cords, extending on
each side of the vertebral column from the base of the skull to the coccyx. It
may, moreover, be traced up into the head, where the ganglia (which are all in
connection with the fifth cranial nerve) occupy spaces between the cranial and
facial bones. These two gangliated cords lie parallel with one another as far
as the sacrum, on which bone they converge, communicating together through
a single ganglion [ganglion impar)^ placed in front of the coccyx. Some ana-
tomists also state that the two cords are joined at their cephalic extremity,
through, a small ganglion (the ganglion of Ribes), situated upon the anterior
communicating artery. Moreover, the chains of opposite sides communicate
between these two extremities in several parts, hj means of the nervous cords
that arise from them.
The ganglia are somewhat less numerous than the vertebrse : thus there are
only three in the cervical region, twelve in the dorsal, four in the lumbar, five
in the sacral, and one in the coccygeal.
The sympathetic nerve, for convenience of description, may be divided into
several parts, according to the position occupied by each ; and the number of
ganglia, of which each part is composed, may be thus arranged:
Cephalic p(
irtion
4 ganglia
Cervical
3
Dorsal
12
Lumbar
4
Sacral
5
Coccygeal
1
Each ganglion may be regarded as a distinct centre, from or to which branches
pass in various directions. These branches may be thus arranged: 1.
Branches of communication between the ganglia. 2. Branches of communica-
tion with the cerebral or spinal nerves. 3. Primary branches passing to be
distributed to the arteries in the vicinity of the ganglia, and to the viscera, or
proceeding to other ganglia placed in the thorax, abdomen, or pelvis.
1. The branches of communication between the ganglia are composed of gray
and white nerve-fibres, the latter being continuous with those fibres of the
spinal nerves which pass to the ganglia.
2. The brandies of communication between the ganglia and the cerebral or
spinal nerves also consist of a white and a gray portion ; the former proceeding
from the spinal nerve to the ganglion, the latter passing from the ganglion to
the spinal nerve.
3. The primary branches of distribution also consist of two kinds of nerve-
fibres, the sympathetic and spinal. They have a remarkable tendency to form
intricate pl(!xusos, which encircle the bloodvessels, and arc conducted by them
to the viscera. The greater number, however, of these branches pass to a series
of visceral ganglia; these are ganglionic masses, of variable size, situated in the
large cavities of the trunk, the thorax, and al)domen ; and are connected with
the roots of the great arteries of the viscera. '^J''iie visceral ganglia are single
and unsymmetrical, and are called the cardiac ami semilunar. From these
( my )
SYMPATHETIC NERVE,
Fig. 391.— The Sympathetic Nerve.
rccrotm. FJexns
697
Siipenor Cttrvirtf? nrrnq7inn —
Inferior Cervical Ganglion
l^nryrtri^fzl Zi fa ticibe»
CarJiac Br4
J}cep Cardiac Plexus
Superficial Cardiac Plexus
— Solftr plexus
Aortic PlexiiS
lit/j} agastric J'te^i.
Sacrnl Ganitlia
a.!.nrjJio,t In,,
698 SYMPATHETIC NERVE.
visceral ganglia numerous plexuses of nerves are derived, wliicli entwine round
the bloodvessels and are conducted by tbeni to the viscera.
The cej^lialic "portion of the sympathetic consists of four ganglia: 1. The
ophthalmic ganglion. 2. The spheno-palatine, or Meckel's ganglion, 3. The
otic, or Arnold's ganglion. 4. The submaxillary ganglion.
These have been already described in connection with the three divisions of
the fifth nerve.
Cervical PoRTioisr of the Sympathetic.
The cervical portion of the sympathetic consists of three ganglia on each side,
which are distinguished according to their position, as the superior, middle, and
inferior cervical.
The Superior Cervical Ganglion, the largest of the three, is placed opposite
the second and third cervical vertebree and sometimes as low as the fourth or
fifth. It is of a reddish-gray color, and usually fusiform in shape; sometimes
broad, and occasionally constricted at intervals, so as to give rise to the opinion
that it consists of the coalescence of several smaller ganglia. It is in relation,
in front, with the sheath of the internal carotid artery, and internal jugular
vein; behind it lies on the Eectus capitis anticus major muscle.
Its branches may be divided into superior, inferior, external, internal, and
anterior.
The superior hranch appears to be a direct continuation of the ganglion. It
is soft in texture, and of a reddish color. It ascends by the side of the internal
carotid artery, and, entering the carotid canal in the temporal bone, divides into
two branches, which lie, one on the outer, and the other on the inner side of
that vessel.
The outer hranch^ the larger of the two, distributes filaments to the internal
carotid artery, and forms the carotid plexus.
The inner hranch also distributes filaments to the internal carotid, and, con-
tinuing onwards, forms the cavernous plexus.
The Carotid Plexus is situated on the outer side of the internal carotid.
Filaments from this plexus occasionally form a small gangliform swelling on
the under surface of the artery, which is called the carotid ganglion. The
carotid plexus communicates with the Casserian ganglion, with the sixth nerve,
and spheno-palatine ganglion, and distributes filaments to the wall of the carotid
artery, and to the dura mater (Yalentine).
The communicating branches with the sixth nerve consist of one or two fila-
ments which join that nerve as it lies upon the outer side of the internal carotid.
Other filaments are also connected with the Casserian ganglion. The communi-
cation with the spheno-palatine ganglion is effected by the carotid portion of
the Vidian nerve, which passes forwards, through the cartilaginous substance
filling the foramen lacerum medium, along the pterygoid or Vidian canal, to
the spheno-palatine ganglion. In this canal it joins the petrosal branch of the
Vidian.
The Cavernous Plexus is situated below, and internal to that part of the
internal carotid, which is placed by the side of the sella Turcica, in the caver-
nous sinus, and is formed chiefly by the internal division of the ascending
branch from the superior cervical ganglion. It communicates with the third,
fourth, fifth, and sixth nerves, and with the ophthalmic ganglion, and distrib-
utes filaments to the wall of the internal carotid. The branch of communication
with the third nerve joins it at its point of division; the branch to the fourtli
nerve joins it as it lies on the outer wall of the cavernous sinus; other filaments
are connected with the under surface of the trunk of the pplilhalmic nerve; and
a second filament of communication joins the sixth nerve.
The filament of connectif)n with llic ophthalmic ganglion arises from the
anterior part of tlie cavernous ])lcxus; it accomjianies the nasal nerve, or
continues forwards as a separate branch.
CERVICAL GANGLIA, 699
The terminal filaments from tlie carotid and cavernous plexuses are prolonged
along the internal carotid, forming plexuses which entwine round the cerebral
and ophthalmic arteries ; along the former vessel they may be traced on to the
pia mater ; along the latter, into the orbit, where they accompany each of the
subdivisions of the vessel, a separate plexus passing with the arteria centralis
retinae into the interior of the eyeball.
The inferior or descending branch of the superior cervical ganglion communi-
cates with the middle cervical ganglion.
The external hroMches are numerous, and communicate with the cranial nerves,
and with the four upper spinal nerves. Sometimes, the branch to the fourth
spinal nerve may come from the cord connecting the upper and middle cervical
ganglia. The branches of communication with the cranial nerves consist of deli-
cate filaments, which pass from the superior cervical ganglion to the ganglion
of the trunk of the pneumogastric, and to the ninth nerve. A separate filament
from the cervical ganglion subdivides and joins the petrosal ganglion of the
glosso-pharyngeal, and the ganglion of the root of the pneumogastric in the
jugular foramen.
The internal branches are three in number : pharyngeal, laryngeal, and the
superior cardiac nerve. The pharyngeal branches pass inwards to the side of
the pharynx, where they join with branches from the pneumogastric, glosso-
pharyngeal, and external laryngeal nerves to form \h% pharyngeal plexus. The
laryngeal branches unite with the superior lar^aigeal nerve and its branches.
The superior cardiac nerve will be described in connection with the other
cardiac nerves.
The anterior branches ramify upon the external carotid artery and its branches,
forming around each a delicate plexus, on the nerves composing which small
ganglia are occasionally found. These ganglia have been named, according to
their position, interoarotid (one placed at the angle of bifurcation of the common
carotid), lingual, temporal, and pharyngeal. The plexuses accompanying some-of
these arteries have important communications with other nerves. That sur-
rounding the external carotid, is connected with the digastric branch of the facial ;
that surrounding the facial, communicates with the submaxillary ganglion by
one or two filaments ; and that accompanying the middle meningeal artery, sends
offsets which pass to the optic ganglion and to the intumescentia ganglioformis
of the facial nerve (external petrosal).
The Middle Cervical GangliojST (thyroid ganglion) is the smallest of the
three cervical ganglia, and is occasionally altogether wanting. It is placed oppo-
site the fifth cervical vertebra, usually upon, or close to, the inferior thyroid
artery ; hence the name "thyroid ganglion," assigned to it by Haller.
Its superior branches ascend to communicate with the superior cervical
ganglion.
Its inferior branches descend to communicate with the inferior cervical
ganglion.
Its external branches pass outwards to join the fifth and sixth spinal nerves.
^ Those branches are not constantly found.
Its internal branches are the thyroid and the middle cardiac nerve.
The thyroid branches are small filaments, which accompany the inferior th}^-
roid artery to the thyroid gland; they communicate, on the artery, with the
superior cardiac nerve, and in the gland, with branches from the recurrent and
external laryngeal nerves.
The middle cardiac nerve is described with the other cardiac nerves.
The Inferior Cervical Ganglion is situated between the base of the trans-
verse process of the last cervical vertebra, and the neck of the first rib, on the
inner side of the superior intercostal artery. Its form is irregular; it is larger
in size than the preceding, and frequently joined with the first thoracic ganglion.
Its superior branches communicate with the middle cervical ganglion.
Its inferior branches descend, some in front of, others behind the subclavian
700 SYMPATHETIC NERVE.
artery, to join the first tlioracic gang-lion. The most important of these branches
constitutes the inferior cardiac nerve, to be presently described.
The external branches consist of several filaments, some of which communicate
with the seventh and eighth spinal nerves; others accompany the vertebral
artery along the vertebral canal, forming a plexus round the vessel, supplying
it with filaments, and communicating with the cervical spinal nerves as high as
the fourth.
Cardiac Nerves.
The Cardiac Nerves are three in number on each side : superior, middle, and
inferior, one being derived from each of the cervical ganglia.
The superior cardiac nerve (nervus superficialis cordis) arises by tAvo or more
branches from the superior cervical ganglion, and occasionally receives a filament
from the cord of communication between the first and second cervical ganglia.
It runs down the neck behind the common carotid artery, lying upon thelongus
colli muscle ; and crosses in front of the inferior thyroid artery, and the recur-
rent laryngeal nerve.
The right superior cardiac nerve^ at the root of the neck, passes either in front
of or behind the subclavian artery, and along the arteria innominata, to the back
part of the arch of the aorta, where it joins the deep cardiac plexus. This nerve,
in its course, is connected with other branches of the sympathetic ; about the
middle of the neck it receives filaments from the external laryngeal nerve ; lower
down, one or two twigs from the pneumogastric ; and as it enters the thorax, it
joins with the recurrent laryngeal. Filaments from this nerve accompany the
inferior thyroid artery to the thyroid gland.
The left superior cardiac nerve runs by the side of the left carotid artery, and
in front of the arch of the aorta, to the superficial cardiac plexus; but occasion-
ally it passes behind the aorta, and terminates in the deep cardiac plexus.
The middle cardiac nerve (nervus cardiacus magnus), the largest of the three,
arises from the middle cervical ganglion, or from the cord between the middle
and inferior ganglia. On the right side, it descends behind the common carotid
artery ; and at the root of the neck, passes either in front of, or behind the
subclavian artery; it then descends on the trachea, receives a few filaments
from the recurrent laryngeal nerve, and joins the deep cardiac plexus. In the
neck, it commu.nicates with the superior cardiac and recurrent laryngeal nerves.
On the left side, the middle cardiac nerve enters the chest between the left
carotid and subclavian arteries, and joins the left side of the deep cardiac plexus.
The inferior cardiac nerve (nervus cardiacus minor) arises from the inferior
cervical or first thoracic ganglion. It passes down behind the subclavian artery
and along the front of the tracliea, to join the deep cardiac plexus_. It commu-
nicates freely behind the subclavian artery with the recurrent huTngeal and
middle cardiac nerves.
The great or deep cardiac plexus {plexus magnus profundus — Scarpa) is situ-
ated in front of the trachea at its bifurcation, above the point of division of the
])ulmonary artery, and behind the arch of the aorta. It is formed by the cardiac
nerves derived from the cervical ganglia of the sympathetic, and the cardiac
branches of the recurrent laryngeal and pneumogastric. The only cardiac nerves
which do not enter into the formation of this plexus are the left superior cardiac
nerve, and the left inferior cardiac branch from the pneumogastric. The
branches derived from the great cardiac plexus form the posterior coronary
])lexus and part of the anterior coronary plexus; whilst a few filaments proceed
to the pulmonary plexuses, and to the auricles oi the heart.
The branches from the right side of this plexus pass, some in front of, and
others bcliind the right pnbnonary arterv; lhe formor, the more numerous,
transmit a ('<'\v filaments 1o tlif^ anterior |)uhii<)iiaf\' ])l(\\iis, and are continued
along the li'iiiih (jf the puhiionary artci'v, to jbrm part of the anterior coi'onaiy
SPLANCHNIC NERVES. 701
plexus ; tliose beLiud the pulmonary artery distribute a few filaments to the
right auricle, and form part of the posterior coronary plexus.
The branches from the left side of the deep cardiac plexus distribute a few-
filaments to the left auricle of the heart and the anterior pulmonary plexus, and
then pass on to form the greater part of the posterior coronary plexus, a few
branches passing to the superficial cardiac plexus.
The superficial {anterior) cardiac plexus lies beneath the arch of the aorta, in
front of the right pulmonary artery. It is formed by the left superior cardiac
nerve, the left (and occasionally the right) inferior cardiac branches of the pneu-
mogastric, and filaments from the deep cardiac plexus. A small ganglion
(cardiac ganglion of Wrisberg) is occasionally found connected with these nerves
at their point of junction. This ganglion, when present, is situated immediately
beneath the arch of the aorta, on the right side of the ductus arteriosus. The
superficial cardiac plexus forms the chief part of the anterior coronary plexus,
and several filaments pass along the pulmonary artery to the left anterior pulmo-
nary plexus.
'ih.Q posterior coronary plexus is chiefly formed by filaments prolonged from
the left side of the deep cardiac plexus, and by a few from the right side. It
surrounds the branches of the coronary artery at the back of the heart, and its
filaments are distributed with those vessels to the muscular substance of the
ventricles.
The anterior coronary plexus is formed chiefly from the superficial cardiac
plexus, but receives filaments from the deep cardiac plexus. Passing forwards
between the aorta and pulmonary artery, it accompanies the right coronary
artery on the anterior surface of the heart.
Valentine has described nervous filaments ramifying under the endocardium ;
and Remak has found, in several mammalia, numerous small ganglia on the
cardiac nerves, both on the surface of the heart and in its muscular substance.
The elaborate dissections of the late Dr. Eobert Lee have demonstrated without
any doubt the existence of a dense mesh of nerves distributed both to the sur-
face and in the substance of the heart, having numerous ganglia developed upon
them.
Thoeacic Poetiox of the Sympathetic.
The thoracic portion of the sympathetic consists of a series of ganglia, which
usually correspond in number to that of the vertebras ; but, from the occasional
coalescence of two, their number is uncertain. These ganglia are placed on each
side of the spine, resting against the heads of the ribs, and covered b}^ the pleura
costalis: the last two are, however, anterior to the rest, being placed on the side
of the bodies of the vertebrge. The ganglia are small in size, and of a grayish
color. The first, larger than the rest, is of an elongated form, and usually
blended with the last cervical. They are connected together by cord-like pro-
longations from their substance.
The external hra,nches from each ganglion, usually two in number, communi-
cate with each of the dorsal spinal nerves.
The internal branches from the six upper ganglia are very small: they supply
filaments to the thoracic aorta and its branches, besides small branches to the '
bodies of the vertebrae and their ligaments. Branches from the third and fourth
ganglia form part of the posterior pulmonary plexus.
The internal branches from the six loiver ganglia are large and white in color;
they distribute filaments to the aorta, and unite to form the three splanchnic
nerves. These are named, the grectt^ the lesser^ and the smallest or renal
splanchnic.
The great splanchnic nerve is of a white color, firm in texture, and bears a
marked contrast to the ganglionic nerves. It is formed by branches from the
thoracic ganglia between the sixth and tenth, receiving filaments (according to
702 SYMPATHETIC NERVE.
Dr. Beck) from all tlie tlioracic ganglia above tlie sixtli. These roots unite to
form a large round cord of considerable size. It descends obliquely inwards in
front of tlie bodies of the vertebras along the posterior mediastinum, perforates
the crus of the Diaphragm, and terminates in the semilunar ganglion, distri-
buting filaments to the renal plexus and suprarenal capsule.
The lesser splanchnic nerve is formed by filaments from the tenth and eleventh
ganglia, and from the cord between them. It pierces the Diaphragm with the
preceding nerve, and joins the coeliac plexns. It communicates in the chest
with the great splanchnic nerve, and occasionally sends filaments to the renal
plexus.
The smallest or renal splanchnic nerve arises from the last ganglion, and
piercing the Diaphragm, terminates in the renal plexus and lower part of the
coeliac plexus. It occasionally communicates with the preceding nerve.
A striking analogy appears to exist between the splanchnic and the cardiac
nerves. The cardiac nerves are three in number ; they arise from the three
cervical ganglia, and are distributed to a large and important organ in the
thoracic cavity. The splanchnic nerves, also three in number, are connected
probably with all the dorsal ganglia, and are distributed to imjDortant organs in
the abdominal cavity.
The epigastric or solar plexus supplies all the viscera in the abdominal cavity.
It consists of a great network of nerves and ganglia, situated behind the stomach
and in front of the aorta and crura of the Diaphragm. It surrounds the coeliac
axis and root of the superior mesenteric artery, extending downwards as low as
the pancreas, and outwards to the suprarenal capsules. This plexus, and the
ganglia connected with it, receive the great splanchnic nerve of both sides, part
of the lesser splanchnic nerves, and the termination of the right pneumogastric.
It distributes filaments, which accompany, under the name of plexuses, all the
branches from the front of the abdominal aorta.
The semilunar ganglia of the solar plexus, two in number, one on each side,'
are the largest ganglia in the body. They are large irregular gangliform
masses, formed by the aggregation of smaller ganglia, having interspaces between
them. They are situated by the side of the coeliac axis and superior mesenteric
artery, close to the suprarenal capsules : the one on the right side lies beneath
the vena cava; the upper part of each ganglion is joined by the greater and
lesser splanchnic nerves, and to the inner side of each the branches of the solar
plexus are connected. From the solar plexus are derived the following : —
Phrenic or diaphragmatic plexus. Suprarenal plexus.
Coeliac plexus. Eenal plexus.
Gastric plexus. Superior mesenteric plexus.
Hepatic plexus. Spermatic plexus.
Splenic plexus. Inferior mesenteric plexus.
The pjhrenic plexus accompanies the phrenic artery to the Diaphragm, which
it supplies, some filaments passing to the suprarenal capsule. It arises from the
upper part of the semilunar ganglion, and is larger on the right than on the left
side. In connection with this plexus, on the right side, at its point of junction
with the phrenic nerve, is a small ganglion (ganglion diaphragmaticum). This-
ganglion is placed on the under surface of the Diaphragm, near the suprarenal
capsule. Its branches are distributed to the vena cava, suprarenal capsule, and
the hepatic plexus. There is no ganglion on the left side.
The suprarenal pilaxus is formed by branches from the solar plexus, from the
semilunar ganglion, and from the splanchnic and phrenic nerves, a ganglion
being foruM-il !it ihn point of junction of the latter nerve. It supplies the su])ra-
renal gland. ^I'Ik; brancilios of this plexus are remarkable for their large size,
in comparison with the size of the organ they supply.
The renal ph'.xus is formed by filaments from the solar ])lcxus, the outer part
of the semilunar ganglion, and the aortic plexus. It is also joined by filaments
PLEXUSES IK ABDOMEN. 703
from the lesser and smallest splanclinic nerves. The nerves from these sources,
fifteen or twenty in number, have numerous ganglia developed upon them.
Thej accom|)anj the branches of the renal artery into the kidney ; some fila-
ments on the right side being distributed to the vena cava, and others to the
spermatic plexus, on both sides.
The spermatic plexus is derived from the renal plexus, receiving branches from
the aortic plexus. It accompanies the spermatic vessels to the testes.
In the female, the ovarian plexus is distributed to the ovaries and fundus of
the uterus.
The coeliac plexus^ of large size, is a direct continuation from the solar plexus:
it surrounds the coeliac axis, and subdivides into the gastric, hepatic, and splenic
plexuses. It receives branches from one or more of the splanchnic nerves, and,
on the left side, a filament from the pneumogastric.
The gastric plexus accompanies the gastric artery along the lesser curvature
of the stomach, and joins with branches from the left pneumogastric nerve. It
is distributed to the stomach.
The hepatic plexus^ the largest offset from the coeliac plexus, receives filaments
from the left pneumogastric and right phrenic nerves. It accompanies the
hepatic artery, ramifying in the substance of the liver, upon its branches, and
upon those of the vena port<«.
Branches from this plexus accompany all the divisions of the hepatic artery.
Thus there is a pyloric plexus accompanying the pyloric branch of the hepatic,
which joins with the gastric plexus, and pneumogastric nerves. There is also
a gastro-duodeual plexus, which subdivides into the pancreatico-duodeual plexus,
which accompanies the pancreatico-duodenal artery, to supply the pancreas and
duodenum, joining with branches from the mesenteric plexus ; and a gastro-
epiploic plexus, which accompanies the right gastro- epiploic artery along the
greater curvature of the stomach, and anastomoses with branches from the
splenic plexus. A cystic plexus, which supplies the gall-bladder, also arises
from the hepatic plexus, near the liver.
The splenic plexus is formed by branches from the right and left semilunar
ganglia, and from the right pneumogastric nerve. It accompanies the splenic
artery and its branches to the substance of the spleen, giving off, in its course,
filaments to the pancreas (pancreatic plexus), and the left gastro-epiploic plexus,
which accompanies the gastro-epiploica sinistra artery along the convex border
of the stomach.
The superior inesenteric plexus is a continuation of the lower part of the great
solar plexus, receiving a branch from the junction of the right pneumogastric
nerve with the coeliac plexus. It surrounds the superior mesenteric artery,
which it accompanies into the mesentery, and divides into a number of secondary
plexuses, which are distributed to all the parts supplied by the artery, viz.,
pancreatic branches to the pancreas; intestinal branches, which supply the
whole of the small intestine ; and ileo-colic, right colic, and middle colic
branches, which supply the corresponding parts of the great intestine. The
nerves composing this plexus are white in color, and firm in texture, and have
numerous ganglia developed upon them near their origin.
The aortic plexus is formed by branches derived, on each side, from the
semilunar ganglia and renal plexuses, receiving filaments from some of the
lumbar ganglia. It is situated upon the sides and front of the aorta, between
the origins of the superior and inferior mesenteric arteries. From this plexus
arise the inferior mesenteric, part of the spermatic, and the hypogastric plexuses ;
and it distributes filaments to the inferior vena cava.
The inferior mesenteric plexus is derived chiefly from the left side of the aortic
plexus. It surrounds the inferior mesenteric artery, and divides into a number
of secondary plexuses, which are distributed to all the parts supplied by the
artery, viz., the left colic and sigmoid plexuses, which supply the descending
and sigmoid flexure of the colon ; and the superior hemorrhoidal plexus, which
704 SYMPATHETIC NERVE.
supplies tlie upper part of the rectum, and joins in tlie pelvis with branclies
from the left hypogastric plexus.
Lumbar Portion of the Sympathetic.
The lumbar portion of the sympathetic is situated in front of the vertebral
column, along the inner margin of the Psoas muscle. It consists usually of
four ganglia, cpnnected together by interganglionic cords. The ganglia are of
small size, of a grayish color, shaped like a barleycorn, and placed much nearer
the median line than the thoracic ganglia.
The superior and inferior tranches of the lumbar ganglia serve as communi-
cating branches between the chain of ganglia in this region. They are usually
single and of a white color.
The external hranches communicate with the lumbar spinal nerves. From the
situation of the lumbar ganglia, these branches are longer than in the other
regions. They are usually two in number for each ganglion, and accompau}^
the lumbar arteries around the sides of the bodies of the vertebra, passing
beneath the fibrous arches from which some of the fibres of the Psoas muscle
arise.
The internal hranches pass inwards, in front of the aorta, and form the lumbar
aortic plexus, already described. Other branches descend in front of the common
iliac arteries, and join, over the promontory of the sacrum, to form the hypo-
gastric plexus. Numerous delicate filaments are also distributed to the bodies
of the vertebrae, and the ligaments connecting them.
Pelvic Portiojst of the Sympathetic.
The pelvic portion of the sympathetic is situated in front of the sacrum, along
the inner side of the anterior sacral foramina. It consists of four or five small^
ganglia on each side, connected together by interganglionic cords. Below, these
cords converge and unite on the front of the coccyx, by means of a small gan-
glion (ganglion impar).
The sujjerior and inferior hranches are the cords of communication between
the ganglia above and below.
The external hranches^ exceedingly short, communicate with the sacral nerves.
They are two in number to each ganglion. The coccygeal nerve communicates
either with the last sacral, or coccygeal ganglion.
The internal hranches communicate, on the front of the sacrum, with the
corresponding branches from the opposite side ; some, from the first two
ganglia, pass to join the pelvic plexus, and others form a plexus, which accom-
panies the middle sacral artery.
The hypogastric plexus supplies the viscera of the pelvic cavity. It is situated
in front of the promontory of the sacrum, between the two common iliac arteries,
and is formed by the union of numerous filaments, which descend on each side
from the aortic plexus, from the lumbar ganglia, and from the first two sacral
ganglia. This plexus contains no ganglia; and bifurcates, below, into two
lateral portions, which form the inferior hypogastric, or pelvic plexuses.
Inferior Hypogastric, or Pelvic Plexus.
The Inferior ITypogastric, or Pelvic Plexus, is situated at the side of the
rectum and bladder in the male, and at the side of the rectum, vagina, and
bladder, in llie f<'.iiialo. It is formed by a continuation of the hypogastric
plexus, T)y branclies from the second, third, and fourth sacral nerves, and by a
few filaments from the sacral ganglia. At the point of junction of these nerves,
small ganglia arc found. From this plexus numerous liranches are distributed
to all llie viscera of the pelvis. They accompany the branches of the internal
iliac artery.
GANGLIA AND NERVES OF THE GRAVID UTERUS. 705
Fig. 392. — Ganglia and Nerves of the Gravid Uterus at the end of the Ninth Month.
After Dr. R. Lee.
A. The fundus and body of the uterus, having the peritoneum dissected off from the left side. B. The vagina
covered with nerves proceeding from the inferior border of the left hypogastric ganglion. C. The rectum. D. Tlio
left ovarium and Fallopian tube. E. The trunk of the left spermatic vein and artery surrounded by the left spermatic
ganglion. F. The aorta divided a little above the origin of the right spermatic artery, and about three inches above
its division into the two common, iliac arteries. G. The vena cava. H. Trunk of the right spermatic vein entei'ing
the vena cava. I. Eight ureter. K. The two cords of tlie great sympathetic nerve passing down along the front of
the aorta. L. Trunk of the inferior mesenteric artery, passing off from the aorta, and covered with a great plexus
of nerves sent off from the left and right cords of the great sympathetic. M. M. The two cords of the great sympa-
thetic passing down below the bifurcation of the aorta to the point where they separate into the right and left
hypogastric nerves. N. The right hypogastric nerve with its artery injected proceeding to the neck of the uterus,
to terminate in the right hypogastric ganglion. 0. The left hypogastric nerve where it is entering the left hypo-
gastric ganglion, and giving off branches to the left subperitoneal ganglion. P. Hemori-hoidal nerves accompanying
the hemorrhoidal artery and proceeding from tlie great plexus which surrounded the inferior mesenteric artery. Q.
The sacral nerves entering the whole outer surface of the hypogastric ganglion. E. The left hypogastric ganglion
with its arteries injected. S. The nerves of the vagina. T. Nerves with an injected artery proceeding from the
upper part of the left hypogastric ganglion along the body of the uterus, and terminating in the left spermatic
ganglion. U. Continuation of these nerves and the branches which they give off to the subperitoneal plexuses. V.
The same nerves passing upward beneath the subperitoneal plexuses, and anastomosing freely with them. W. The
left spermatic ganglion, in which the nerves and artery from the hypogastric ganglion, and the branches of the left
subperitoneal plexuses terminate, and from which the nerves of the fundus uteri are supplied. X. The left sub-
peritoneal plexuses covering the body of the uterus. Y. The left subperitoneal ganglion^ with numerous branches
of nerves extending between it and the left hypogastric nerve and ganglion. Z. The lett common iliac artery cut
across and turned aside, that the left hypogastric nerve and ganglion might be traced and exposed.
45
706 SYMPATHETIC NERVE.
Tlie inferior hemorrhoidal plexus arises from tlie back part of the pelvic
plexus. It supplies tlie rectum, joining with, branches of the superior hemor-
rhoidal plexus.
The vesical plexus arises from the fore part of the pelvic plexus. The nerves
composing it are numerous, and. contain a large proportion of spinal nerve fibres.
They accompany the vesical arteries, and are distributed at the side and base
of the bladder. Numerous filaments also pass to the vesicul^ seminales, and
vas deferens: those accompanying the vas deferens join on the spermatic cord,
with branches from the spermatic plexus.
^h.e prostatic plexus is continued from the lower part of the pelvic plexus. The
nerves composing it are of large size. They are distributed to the prostate gland,
vesicul;© seminales, and erectile structure of the penis. The nerves supplying
the erectile structure of the penis consist of two sets, the small and large caver-
nous nerves. They are slender filaments, which arise from the fore part of the
prostatic plexus; and after joining vvdth branches from the internal pudic nerve,
pass forwards beneath the pubic arch.
The small cavernous nerves perforate the fibrous covering of the penis, near
its roots.
The large cavernous nerve passes forwards along the dorsum of the penis, joins
with the dorsal branch of the pudic nerve, and is distributed to the corpus caver-
nosum and spongiosum.
The vaginal plexus arises from the lower part of the pelvic plexus. It is lost
on the walls of the vagina, being distributed to the erectile tissue at its anterior
part, and to the mucous membrane. The nerves composing this plexus contain,
like the vesical, a large proportion of spinal nerve-fibres.
The uterine nerves arise from the lower part of the hypogastric plexus, above
the point where the branches from the sacral nerves join the pelvic plexus. They
accompany the uterine arteries to the side of the organ between the layers of
the broad ligament, and are distributed to the cervix and lower part of the body
of the uterus, penetrating its substance.
Other filaments pass separately to the body of the uterus and Fallopian tube.
Branches from the hypogastric plexus accompany the uterine arteries into
the substance of the uterus. Upon these filaments ganglionic enlargements are
found.
For a detailed account of the supply of nerves to the uterus, and for a description of the changes
which those nerves and their ganglia undergo during pregnancy, the reader is referred to the
papers on " The Anatomy of the Nerves of the Uterus," published by Dr. Robert Lee.
Organs of Sense.
The Organs of tlie Senses are five in number, viz., tliose of touch, of taste,
of smell, of hearing, and of sight. The skin, which is the principal seat of the
sense of touch, has been described in the Introduction.
The Tongue.
The Tongue is the organ of the special sense of taste. It is situated in the
floor of the mouth, in the interval between the two lateral portions of the body
of the lower jaw. Its base, or root, is directed backwards, and connected with
theoshyoides by numerous muscles, with the epiglottis by three folds of mucous
Fig. 393. — Upper Surface of the Tongue.
I'd i form
Yxg.'i'i^. T/ie3 kinch of V^?\\.^^ ^narjnificd
Secontfary
Cu'cu ni/itcrlTa te
(707)
708 ORGANS OF SENSE.
membrane, wliich form the glosso-epiglottic ligaments, and witli the soft palate
and pharynx by means of the anterior and posterior pillars of the fauces. Its
apex or tip, thin and narrow, is directed forwards against the inner surface of
the lower incisor teeth. The under surface of the tongue is connected with the
lower jaw by the Genio-hyo-glossi muscles ; from its sides, the mucous mem-
brane is reflected to the inner surface of the gums ; and, in front, a distinct fold
of that membrane, the frsenum linguse^ is formed beneath its under surface.
The tip of the tongue, part of its under surface, its sides, and dorsum, are
free.
The dorsum of the tongue is convex, marked along the middle line by a
raphe, which divides it into two symmetrical halves ; and this raphe teriuinates
behind, about half an inch from the base of the organ, a little in front of a deep
mucous follicle, the foramen csecum. The anterior two-thirds of this surface are
rough and covered with papillee ; the posterior third is more smooth, and
covered by the projecting orifices of numerous muciparous glands.
The mucous memhrane invests the entire extent of the free surface of the
tongue. On the under surface of the organ it is thin and smooth, and may be
traced on either side of the frgenum, through the ducts of the submaxillary
glands; and between the sides of the tongue and the lower jaw, through the
ducts of the sublingual glands. As it passes over the borders of the organ, it
gradually assumes its papillary character.
The mucous membrane of the tongue consists of structures analogous to those
of the skin, namely, a cutis or corium,^ supporting numerous papillse^ and covered,
as well as the papillse, with epitJielium,.
The cutis is tough, but thinner and less dense than in most parts of the skin,
and is composed of similar tissue. It contains the ramifications of the numerous
vessels and nerves from which the papillee are supplied, and affords insertion to
all the intrinsic muscular fibres of the organ.
The papillge of the tongue are thickly distributed over the whole of its upper
surface, giving to it its characteristic roughness. They are more prominent than
those of the skin, standing out from the surface like the villi of the intestine.
The principal varieties are the papillae maximte (circumvallatEe), papillas medi^
(fungiformes), and papillae minimse (conica3 or filiformes).
The papillw maximse (circumvallat£e) are of large size, and vary from eight
to ten in number. They are situated at the back part of the dorsum of the
tongue, near its base, forming a row on each side, which running backwards and
inwards, meet in the middle line, like the two lines of the letter V inverted.
Each papilla consists of a central flattened projection of mucous membrane,
circular in form, from ^-^ to y'^ of an inch wide, attached to the bottom of a
cup-shaped depression of the mucous membrane ; the exposed part being studded
with numerous small papilke, which, however, are covered by a smooth laj^er
of the epithelium. The cup-shaped depression forms a kind of fossa round the
papilla, having a circular margin of about the same elevation, covered with
smaller papillae. The fissure corresponding to the papilla, which is situated at
the junction of the two lines of the circumvallate papil]a3, is so large and deep,
that the ndiVciQ foramen csecum has been applied to it. In the smaller papillae,
the fissure exists only on one side.
The papillse m,edix (fungiformes), more numerous than the preceding, are
scattered irregularly and sparingly over the dorsum of the tongue ; but are
found chiefly at its sides and apex. They are easily recognized, among the
other papilke, by their large size, rounded eminences, and deep red color. They
are narrow at their attachment to the tongue, but broad and rounded at their
free extremities, and covered with secondary papillas. Their epithelial invest-
ment is very thin.
^^\\(i pdpilhjc m.inimve (conicre — filiformes) cover the anterior two-thirds of the
dorsum of the tongue. They arc very minute, more or less conical or filiform
in shape, and arranged in lines corresponding in direction with the two rows of
THE TONGUE. 709
tlie papillee circum vallat^e ; excepting at tlie apex of the organ, where their
direction is transverse. The filiform papillas are of a whitish tint, owing to the
thickness and density of their epithehum ; they are covered with numerous
secondary papillaB, are firmer and. more elastic than the papillas of mucous
membrane generally, and often inclose minute hairs.
Simple painllse^ similar to those of the skin, are dispersed very unequally among
the compound forms, and exist sparingly on the surface of the tongue behind
the circumvallate variety, buried under a layer of epithelium.
Structure of the papillae. The papillse apparently resemble in structure those
of the cutis, consisting of a cone-shaped projection of homogeneous tissue,
covered with a thick layer of squamous epithelium, and contain one or more
capillary loops, amongst which nerves are distributed in great abundance. If
the epithelium is removed, it will be found that they are not simple processes
like the papillte of the skin, for the surface of each is studded with minute
conical processes of the mucous membrane, which form secondary papillse (Todd
and Bowman). In the papillaa circumvallatee, the nerves are numerous and of
large size; in the papillce fungiformes they are also numerous, and terminate in
a plexiform network, from which brush-like branches proceed; in the papillae
filiformes, their mode of termination is uncertain. Buried in the epidermis of
the papillae circumvallatte, and in some of the fungiformes, certain peculiar bodies
called taste-corpuscles have been described. They are flask-like in shape, their
broad base resting on the corium, and their neck opening by an orifice between
the cells of the epithelium. They are formed by two kinds of cell : the exterior,
which are arranged in several layers, being spindle-shaped; the internal, con-
sisting of nuclei with processes on either side, of which the deep one is described
as continuous with the terminal fibril of a nerve, while the superficial projects
as an extremely fine hair through the orifice of the taste-corpuscle.^
Besides the papillae, the mucous membrane of the tongue is provided with
numerous follicles and glands.
The follicles are found scattered over its entire surface, but are especiallj^
numerous between the papillae circumvallatag and the epiglottis. Their walls
contain much lymphoid tissue.
The mucous gla.nds (lingual), similar in structure to the labial and buccal, are
found chiefly beneath the mucous membrane of the posterior third of the dorsum
of the tongue. There is a small group of these glands beneath the tip of the
tongue, a few along the borders of the organ, and some in front of the circum-
vallate papilhe projecting in the muscular substance. Their ducts open either
upon the surface, or into the depressions round the large papillae.
The epithelium is of the scaly variety like that of the epidermis. It covers
the free surface of the tongue, as may be easily demonstrated by maceration, or
boiling, when it can be detached entire : it is much thinner than in the skin :
the intervals between the large papillae are not filled up by it, but each papilla
has a separate investment from root to summit. The deepest cells may some-
times be detached as a separate layer, corres|3onding to the rete mucosum, but
they never contain coloring matter.
The tongue consists of two symmetrical halves, separated from each other, in
the middle line, by a fibrous septum. Each half is composed of muscular fibres
arranged in various directions, containing much interposed fat, and supplied by
vessels and nerves : the entire organ is invested by mucous membrane, and a
submucous fibrous stratum. The latter membrane invests the greater part of
the surface of the tongue, and into it the muscular fibres are inserted that pass
to the surface. It is thicker behind than in front, and is continuous with the
sheaths of the muscles attached to it.
The fibrous septum consists of a vertical layer of fibrous tissue, extending
throughout the entire length of the middle line of the tongue, from the base to
' See Engelmann, in Strieker's Handbook (New Sjd. Soc.'s Trans.), vol. iii. p. 2.
710
ORGANS OF SENSE.
the apex. It is thicker behind than in front, and occasionally contains a small
fibro-cartilage, about a quarter of an inch in length. It is well displayed by
making a vertical section across the organ. Another strong fibrous lamina,
termed the hyo- glossal onembrane, connects the under surface of the base of the
tongue to the body of the hyoid bone. This membrane receives, in front, some
of the fibres of the Genio-hyo-glossi.
Each half of the tongue consists of extrinsic and intrinsic muscles. The former
have been already described; they are the Hyo-glossus, Genio-hyo-glossas, Stylo-
glossus, Palato-glossus, and part of the Superior constrictor. The intrinsic
muscular fibres are described along with the Lingualis on p. 364.
The arteries of the tongue are derived from the lingual, the facial, and ascend-
ing pharyngeal.
The nerves of the tongue are three in number in each half: the gustatory
branch of the fifth, which is distributed to the papillse at the fore part and sides
of the tongue ; the lingual branch of the glosso-pharyngeal, which is distributed
to the mucous membrane at the base and side of the tongue, and to the papillse
circumvallatse ; and the hypoglossal nerve, which is distributed to the muscular
substance of the tongue. The two former are nerves of common sensation and
of taste ; the latter is the motor nerve of the tongue.
The Nose.
The ISTose is the special organ of the sense of smell : by means of the peculiar
properties of its nerves, it protects the lungs from the inhalation of deleterious
gases, and assists the organ of taste in discriminating the properties of food.
The organ of smell consists of two parts, one external, the nose ; the other
internal, the nasal fossge.
The nose is the more anterior and prominent part of the organ of smell. It is
of a triangular form, directed vertically downwards, and projects from the centre
Figs. 395, 396.— Cartilages of the Nose.
See-n froon heZow
LowerZ.ftf.t'i-af Ct
^.Sesainoid Ci
Sidt- Vc.e^^r
of the face, immediately above the ui)])cr lip. Its summit, or root, is connected
directly with the forehead. Its inferior ])art, tlie base of the nose, presents two
elliptical orifices, tlic nostrils, se])arated from each other by an antero-postcrior
Hcptum, tlie columna. The niargins of these orifices are provided with a number
of stiff hairs, or vihrissie^ which arrest the passage of foreign substances carried
with the current of air intended for respiration. The lateral surfaces of the nose
THE NOSE.
711
Fig. 397. — Bones and Cartiln<res of Septum
of Nose. Eight Side.
form, bj tlieir union, the dorsum, tlie direction of wliicli varies considerably in
different individuals. The dorsum terminates below in a rounded eminence, the
lobe of the nose.
The nose is composed of a framework of bones and cartilages, the latter
being slightly acted upon by certain muscles. It is covered externally by the
integument, internally by mucous membrane, and supplied with vessels and
nerves.
The hony frameivorh occupies the upper part of the organ : it consists of the
nasal bones, and the nasal processes of the superior maxillary.
The cartilaginous fraTueworh consists of five pieces, the two upper and the two
lower lateral cartilages, and the cartilage of the septum.
The ujjper lateral cartilages are situated below the free margin of the nasal
bones ; each cartilage is flattened, and triangular in shape. Its anterior margin
is thicker than the posterior, and connected with the fibro-cartilage of the septum.
Its posterior margin is attached to the nasal process of the superior maxillary
and nasal bones. Its inferior margin is connected by fibrous tissue with the
lower lateral cartilage : one surface is turned outwards, fhe other inwards to-
wards the nasal cavity.
The lower lateral cartilages are two thin, flexible plates situated immediately
below the preceding, and curved in such a manner as to form the inner and
outer walls of each orifice of the nos-
tril. The portion which forms the
inner wall, thicker than the rest, is
loosely connected with the same part
of the opposite cartilage, and forms
a small part of the columna. Its
outer extremity, free, rounded, and
projecting, forms, "with the thickened
integument and subjacent tissue, the
lobe of the nose. The part which
forms the outer wall is curved to cor-
respond with the ala of the nose : it
is oval and flattened, narrow behind
where it is connected with the nasal
process of the superior maxilla by
a tough fibrous membrane, in which
are found three or four small carti
laginous plates (sesamoid cartilages),
caHilagines minores. Above, it is con-
nected to the upper lateral cartilage
and front part of the cartilage of the septum ; below, it is separated from the
margin of the nostril by dense cellular tissue ; and in front, it forms, with its
fellow, the prominence of the tip of the nose.
The cartilage of the sejjtum is somewhat triangular in form, thicker at its
margins than at its centre, and completes the separation between the nasal fossse
in front. Its anterior margin, thickest above, is connected from above down-
wards with the nasal bones, the front part of the two upper lateral cartilages,
and the inner portion of the two lower lateral cartilages. Its posterior margin
is connected with the perpendicular lamella of the ethmoid ; its inferior margm
with the vomer and the palate processes of the superior maxillary bones.
These various cartilages are connected to each other, and to the bones, by a
tough fibrous membrane, the perichondrium, which allows the utmost facility
of movement between them.
The muscles of the nose are situated immediately beneath the integument:
they are (on each side) the Pyramidalis nasi, the Levator labii superiorisalceque
nasi, th6 Dilator naris, anterior and posterior, the Compressor nasi, the Cora-
712 ORGANS OF SENSE.
pressor narium minor, and the Depressor alee nasi. Tliese liave already been
described above (p. 349).
The integument covering the dorsum and sides of the nose is thin, and loosely
connected with the subjacent parts; but where it forms the tip, or lobe, and
the alae of the nose, it is thicker and more tirmlj adherent. It is furnished with
a large number of sebaceous follicles, the orifices of which are n.sually very
distinct.
The mucous membrane^ lining the interior of the nose, is continuous with the
skin externally, and with that which lines the nasal fossae within.
The arteries of the nose are the lateralis nasi, from the facial, and the nasal
artery of the septum, from the superior coronary, which supplies the alse and
septum; the sides and dorsum being sujjplied from the nasal branch of the oph-
thalmic and the infraorbital.
The veins of the nose terminate in the facial and ophthalmic.
The nerves of the nose are branches from the facial, infraorbital, and infra-
trochlear, and a filament from the nasal branch of the ophthalmic.
Nasal Foss^.
The Nasal Fossae are two irregular cavities, situated in the middle of the face
and extending from before backwards. They open in front by the two anterior
nares, and terminate in the pharynx, behind, by the posterior nares. The boun-
daries of these cavities, and the openings which are connected with them, as they
exist in the skeleton, have been already described (p. 203).
The mucous membrane lining the nasal fossae is called the pituitary^ from the
nature of its secretion ; or Schneiderian, from Schneider, the first anatomist who
showed that the secretion proceeded from the mucous membrane, and not, as
was formerly imagined, from the brain. It is intimately adherent to the peri-
osteum, or perichondrium, over which it lies. It is continuous externally with
the skin through the anterior nares, and with the mucous membrane of the
pharynx, through the posterior nares. From the nasal fossfe its continuity may
be traced with the conjunctiva, through the nasal duct and lachrymal canals ;
with the lining membrane of the tympanum and mastoid cells, through the Eusta-
chian tube; and with the frontal, ethmoidal, and sphenoidal sinuses, and the
antrum maxillare, through the several openings in the meatuses. The mucous
membrane is thickest, and most vascular, over the turbinated bones. It is also
thick over the septum ; but, in the intervals between the spongy bones, and on
the floor of the nasal fossse, it is very thin. AVhere it lines the various sinuses
and the antrum maxillare, it is thin and pale.
The surface of the membrane is covered with a layer of tessellated epitheliuni,
at the upper part of the nasal fossae, corresponding with the distribution of the
olfactory nerve, but is ciliated throughout the rest of its extent, excepting near
the aperture of the nares.
This membrane is also provided with a nearly continuous laj^er of branched
mucous glands, the ducts of which open upon its surface. They are most nurne-
rous at the middle and back parts of the nasal fossae, and largest at the lower
and back part of the septum.
Owing to the great thickness of this membrane, the nasal fossas are much
narrower, and the turbinated Iwnes, especially the loAver ones, aj^pcar larger and
more prominent than in the skeleton. From the same circumstance, also, the
various apertures communicating with the meatuses are either narrowed or
completely closed.
In the superior meatvs^ the aperture of communication with the posterior
ethmoidal colls is considerably diminished in size, and the spheno-palatine fora-
men completely covered in.
In the middle meatus^ the opening of the ini'undibulum is partially hidden by
THE EYE.
'1 ^
Fig. 398. — Norves of Septum of Nose.
Risrbt Side.
a projecting fold of mucous membrane, and tlie orifice of tlie antrum is con-
tracted to a small circular aperture, much narrower than in the skeleton.
In the inferior meatus, the orifice of the nasal duct is partially hidden by
either a single or double valvular mucous fold, and the anterior palatine canal
either completely closed in, or a tubular cul-de-sac of mucous membrane is
continued a short distance into it.
In the roof, the opening leading to the sphenoidal sinas is narrowed, and the
apertures in the cribriform plate of the ethmoid completely closed in.
The arteries of the nasal fossse are the anterior and posterior ethmoidal, from
the ophthalmic, which supply the ethmoidal cells, frontal sinuses, and roof of
the nose ; the spheno-palatine, from the internal maxillary, which supplies the
mucous membrane covering the spongy bones, the meatuses and septum; and
the alveolar branch of the internal maxillary, which supplies the lining mem-
brane of the antrum. The ramifications of these vessels form a close, plexiform
network, beneath and in the substance of the mucous membrane.
The veins of the nasal fosspe form a close network beneath the mucous mem-
brane. They pass, some with the veins accompanying the spheno-palatine
artery, through the spheno-palatine foramen; and others, through the alveo-
lar branch, join the facial vein; some
accompany the ethmoidal arteries, and
terminate in the ophthalmic vein ; and,
lastly, a few communicate with the
veins in the interior of the skull,
through the foramina in the cribriform
plate of the ethmoid bone, and the
foramen caecum.
The nerves are, the olfactory, the
nasal branch of the ophthalmic, fila-
ments from the anterior dental branch
of the superior maxillary, the Vidian,
naso-palatine, descending anterior pala-
tine, and spheno-palatine branches of
Meckel's ganglion.
The olfactory, the special nerve of
the sense of smell, is distributed over
the upper third of the septum, and over
the surface of the superior and middle
spongy bones.
The nasal branch of the ophthalmic distributes filaments to the upper and
anterior part of the septum, and outer wall of the nasal fossae.
Filaments from the anterior dental branch of the superior maxillary supply the
inferior meatus and inferior turbinated bone.
The Vidian nerve supplies the upper and back part of the septum, and
superior spongy bone ; and the upper anterior nasal branches from the spheno-
palatine ganglion, have a similar distribution.
The naso-palatine nerve supplies the middle of the septum.
The larger, or anterior palatine nerve, supplies the middle and lower spongy
bones.
The Eye.
The Eyeball is contained in the cavity of the orbit. In this situation it ip
securely protected from injury, whilst its position is such as to insure the most
extensive range of sight. It is acted upon by numerous muscles, by which it
is capable of being directed to any part, supplied by vessels and nerves, and is
additionally protected in front by several appendages, such as the eyebrow,
eyelids, etc.
714
ORGANS OF SENSE.
Tlie eyeball is spherical in form, having the segment of a smaller and more
prominent sphere engrafted upon its anterior part. It is from this circumstance
that the antero-posterior diameter of the eyeball, which measures about an inch,
exceeds the transverse diameter by about a line. The segment of the larger
sphere, which forms about five- sixths of the globe, is opaque, and formed by
the sclerotic, the tanic of protection to the eyeball; the smaller sphere, which
forms the remaining sixth, is transparent, and formed by the cornea. The axes
of the eyeballs are nearly parallel, and do not correspond to the axes of the
orbits, which are directed outwards. The optic nerves follow the direction
of the axes of the orbits, and enter the eyeball a little to their inner or nasal
side. The eyeball is composed of several investing tunics, and of fluid and solid
refracting media, called liu'mors.
The tunics are three in number: —
1. Sclerotic and Cornea.
2. Choroid, Iris, and CiHary Processes.
3. Eetina.
The refracting media, or humors, are also three: —
Aqueous. Crystalline (lens) and Capsule. Yitreous.
The sclerotic and cornea form the external tunic of 'the eyeball ; they are
essentially fibrous in structure, the sclerotic being opaque, and forming the
posterior five-sixths of the globe; the cornea, which forms the remaining sixth,
being transparent.
The Sclerotic^ {(^xxr^^o^^ hard) (Fig. 399) has receiTcd its name from its extreme
density and hardness; it is a firm, unyielding, fibrous membrane, serving to
Fig. 399.— A Vertical Section of tlie Eyeball. (Enlarged.)
Ci^Tendon, of RECTUS
Uyaloul 31e mhrane
Ciliary Miitiole
&: Ligament
Circular S/nua
CcL nu I of J'£ Ci ^
maintain tlic f^rm of the gh)bc. It is much thicker bcliind llinn in front. Its
external sv/rfwji is of a white color, quite smooth, except at the points where
the Recti and Obliqui muscles arc inserted into it, and covered, for part of its
extent, by the conjunctival membrane ; hence the whiteness and brilliancy of the
front of the eyol:)all. Its inner svrface is stained of a broAvn color, marked by
grooves, in which arc lodged the ciliary nerves, and connected by an exceedingly
fine cellular tissue {lamina fusca) Avith the outer surface of the choroid, llcliiiid,
SCLEROTIC AND CORNEA. 715
it is pierced by tlie oi^tic nerve a little to its inner or nasal side, and is con-
tinuous with the fibrous sheath of the nerve, which is derived from the dura
mater. At the point where the optic nerve passes through the sclerotic, this
membrane forms a thin cribriform lamina (the lamina crihrosa)'^ the minute
orifices in this layer serve for the transmission of the nervous filaments, and the
fibrous septa dividing them from one another are continuous with the membra-
nous processes which separate the bundles of nerve-fibres. One of these
openings, larger than the rest, occupies the centre of the lamella; it is called
the porus opticus^ and transmits the arteria centralis retina to the interior
of the eyeball. Around the cribriform lamella are numerous small apertures
for the transmission of the ciliary vessels and nerves. In front, the sclerotic is
continuous with the cornea by direct continuity of tissue, but the opaque sclero-
tic overlaps the cornea rather more on its outer than upon its inner surface.
Structure. The sclerotic is formed of white fibrous tissue intermixed with
fine elastic fibres, and fusiform nucleated cells. These are aggregated into
bundles, which are arranged chiefly in a longitudinal direction. It yields
gelatin on boiling. Its vessels are not numerous, the capillaries being of small
size, uniting at long and wide intervals. The existence of nerves in it is
doubtful.
The Cornea is the projecting transparent part of the external tunic of the eye-
ball, and forms the anterior sixth of the globe. It is not quite circular, being
a little broader in the transverse than in the vertical direction, in consequence
of the sclerotic overlapping the margin above and below. It is convex ante-
riorly, and projects forwards from the sclerotic in the same manner that a watch-
glass does from its case. Its degree of curvature varies in different individuals,
and in the same individual at different periods of life, it being more prominent
in youth than in advanced life, when it becomes flattened. The cornea is dense
and of uniform thickness throughout ; its posterior surface is perfectly circular
in outline, and exceeds the anterior surface slightly in extent, from the latter
being overlapped by the sclerotic.
Structure. The cornea consists of five layers: namely, of a thick central
fibrous structure, the cornea proper ; in front of this is the anterior elastic
lamina, covered by the conjunctiva; behind, the posterior elastic lamina,
covered by the lining membrane of the anterior chamber of the eyeball. The
name of membrane of Descemet is given to this posterior elastic lamina and its
epithelial coating.
The proper substance of the cornea is fibrous, tough, unyielding, perfectly
transparent, and continuous with the sclerotic, with which it is in structure
identical. The anastomosing fusiform cells of which it is composed are arranged
in superimposed flattened laminaB, at least sixty in number, all of which have
the same direction, the contiguous laminfe becoming united at frequent intervals.
If the relative position of the component parts of this tissue is in any way
altered, either by pressure or by an increase of its natural tension, it imme-
diately presents an opaque milky appearance. The interstices between the
laminae are tubular, and usually contain a small amount of transparent fluid.
The anterior and posterior elastic laminse^ which cover the proper structure of
the cornea behind and in front, present an analogous structure. They consist
of a hard, elastic, and perfectly transparent homogeneous membrane, of extreme
thinness, which is not rendered opaque by either water, alcohol, or acids. This
membrane is intimately connected by means of a fine cellular web to the proper
substance of the cornea both in front and behind. Its most remarkable pro-
perty is its extreme elasticity, and the tendency which it presents to curl up, or
roll upon itself, with the attached surface innermost, when separated from the
proper substance of the cornea. Its use appears to be (as suggested by Dr.
Jacob), " to preserve the requisite permanent correct curvature of the flaccid
cornea proper."
The conjunctival epithelium.^ which covers the front of the anterior elastic
716
ORGANS OF SENSE.
lamina, consists of t^ro or three layers of transparent nucleated cells, the deepest
being of an oblong form and placed perj)endicular to the surface, the superficial
ones more flattened.
The e-pithelial lining of the aqueous chamber covers the posterior surface of
the posterior elastic lamina. It consists of a single layer of polj^gonal trans-
parent nucleated cells, similar to those found lining other serous cavities.
Arteries and Nerves. The cornea is a non-vascular structure, the capillary
vessels terminating in loops at its circumference. Lymphatic vessels have not
as yet been demonstrated in it. The nerves are numerous, twenty or thirty in
number: they are derived from the ciliary nerves, and enter the laminated
substances of the cornea. They ramify throughout its substance in a delicate
network, and their terminal filaments have been traced by Cohnheim through
the proper substance of the cornea into the deeper layers of the epithelium.
Dissection. In order to separate the sclerotic and cornea, so as to expose the second tunic,
the eyeball should be immersed in a small vessel of water. A fold of the sclerotic near its ante-
rior part having been pinched up, an operation not easily perfoi'med, from the extreme tension
of the membrane, it should be divided with a pair of blunt-pointed scissors. As soon as the
choroid is exposed, the end of a blowpipe should be introduced into the orijBce, and a stream of
air forced into it, so as to separate the slight cellular connection between the sclerotic and
choroid. The sclerotic should now be divided around its entire circumfei-ence, and may be re-
moved in separate portions. The front segment being then drawn forwards, the handle of the
scalpel should be pressed gently against it at its connection with the iris, and these being sepa-
rated, a quantity of perfectly transparent fluid will escape ; this is the aqueous humor. In the
course of the dissection, the ciliary nerves may be seen lying in the loose cellular tissue between
the choroid and sclerotic, or contained in delicate grooves on the inner surface of the latter mem-
brane.
Fig. 400. — The Choroid and Iris. (Enlarged.)
Second Tunic. This is formed by the choroid behind; the iris and ciliary
processes in front; and by the ciliary ligament, and Ciliary muscle, at the point
of junction of the sclerotic and cornea.
The choroid is the vascular and pigmentary tunic of the eyeball, investing
the posterior five-sixths of the globe, and extending as far forwards as the
cornea; the ciliary processes being appendages of the choroid developed from
its inner surface in front. The iris is the circular muscular septum, which
hangs vertically behind the cornea, presenting in its centre a large circular
CHOROID.
717
aperture, tlie pupil. Tlie ciliary ligament and Ciliary muscle form the wliite
ring observed at the point where the choroid and iris join with each other, and
with the sclerotic and cornea.
The Choroid is a thin, highly vascular membrane, of a dark brown or choco-
late color, which invests the posterior five-sixths of the central part of the globe.
It is pierced behind by the optic nerve, and terminates in front at the ciliary
ligament, where it bends inwards, and forms on its inner surface a series of folds
or plaitings, the ciliary processes. It is thicker behind than in front. Externally,
it is connected by a fine cellular web {memhrana fusca) with the inner surface of
the sclerotic. Its inner surface is smooth, and lies in contact Avith the retina.
The choroid is composed of three layers, external, middle, and internal.
Fig. 401.— The Yeius of the Choroid. (Ealarged.) '
The external layer consists, in part, of the larger branches of the short ciliary
arteries, which run forwards between the veins before they bend downwards to
terminate on the inner .surfa.ce. This coat is formed, however, principally of
veins, which are named, from their distribution, vense vorticosse. They converge
to four or five equidistant trunks, which pierce the sclerotic midway between
the margin of the cornea and the entrance of the optic nerve. Interspersed
between the vessels are lodged dark star-shaped pigment-cells, the fibrous offsets
from which, communicating with similar branchings from neighboring cells,
form a delicate network, which, towards the inner surface of the choroid loses
its pigmentary character.
The middle layer consists of an exceedingly fine capillary plexus, formed by
the short ciliary vessels, and is known as the tunica Ruychiana. The network
is close, and finer at the hinder part of the choroid than in front. About half
an inch behind the cornea, its meshes become larger, and are continuous with
those of the ciliary process.
The internal or jpigmentary layer is a delicate membrane, consisting of a single
layer of hexagonal nucleated cells, loaded with pigment-granules, and applied
to each other, so as to resemble a tessellated pavement. Each cell contains a
nucleus, and is filled with grains of pigment, which are in greater abundance at
the circumference of the cell. In perfect albinos this epithelium contains no
pigment, nor is any present in the star-shaped cells found in the other layers of
the choroid.^
' The pigmentary layer is now often described as a portion of the Eetina in consequence of the
method of its development, since it is derived from the same source as that membrane, viz., from
the primary ocular vesicle, furnished by the epiblast, while the choroid is derived from the
mesoblast.
718
ORGANS OF SENSE.
The ciliary processes should now be examined. They may be exposed, either by detaching the
iris from its connection with the ciliary ligament, or by making a transverse section of the globe,
and examining them from behind.
The Ciliary processes are formed by tlie plaiting and folding inwards of tlie
middle and internal layers of the choroid, at its anterior margin, and are received
between corresponding foldings of the suspensory ligament of the lens, thus
establishing a communication between the choroid and inner tunic of the eye.
They are arranged in a circle, behind the iris, round the margin of the lens.
They vary between sixty and eighty in number, lie side by side, and may be
divided into large and small; the latter, consisting of about one-third of the
entire number, are situated in the spaces between the former, but without regu-
lar alternation. The larger processes are each about one-tenth of an inch in
Fig. 402. — The Arteries of the Choroid and Iris. The Sclerotic has beea
mostly removed. (Enlarged.)
Anter£o<if
C I lean/ A^
Shori
CillaTy djr
length, and hemispherical in shape, their periphery being attached to the ciliary
ligament, and continuous with the middle and inner layers of the choroid : the
opposite margin is free and rests upon the circumference of the lens. Their
anterior surface is turned towards the back of the iris, with the circumference
of which it is continuous. The posterior surface is closely connected with the
suspensory ligament of the lens.
Structure. The ciliary processes are similar in structure to the choroid : the
vessels are larger, having chiefly a longitudinal direction. Externally, they are
covered with several layers of pigment-cells; the component cells are small,
rounded, and full of pigment-granules.
The Iris {iris^ a rainbow) has received its name from its various colors in
different individuals. It is a thin, circular-shaped, contractile curtain, suspended
in the aqueous humor behind the cornea, and in front of the lens, being perfo-
rated at the nasal side of its centre by a circular aperture, the pupil, for the
transmission of light. By its circumference it is intimately connected with the
choroid ; externally to this is the ciliary ligament, by which it is connected to
the sclerotic and cornea ; its inner edge forms the margin of the pupil, its sur-
faces arc llattencd, and look forwards and baclcAvards, the anterior surface
towards the cornea, the posterior towards tlie ciliary ])rocesses and lens. The
circumference of the iris is connected to the cornea by a reticular structure
denominated the li(jamentum pectinatu')n iridis. This is a modification of the
membrane of Dcscomct, with which it is continuous. Its fibres cross the outer
part of tliG anterior chamber, forming a kind of canal (the canal of Fontana)
which is occupied by the reticulating fibres of the ligament. The anterior sur-
THE IRIS. 719
face of the iris is variously colored in cliiferent individuals, and marked by lines
which converge towards the pupil. The posterior surface is of a deep purple
tint, from being covered by dark pigment; it is hence named uvea from its
resemblance in color to a ripe grape.
Structure. The iris is composed of a fibrous stroma, muscular fibres, and
pigment-cells.
The fibrous stroma consists of fine, delicate bundles of fibrous tissue, which
have a circular direction at the circumference ; but the chief mass radiate
towards the pupil. They form, by their interlacement, a delicate mesh, in
which the pigment-cells, vessels, and nerves are contained.
The muscular fibre is involuntary, and consists of circular and radiating fibres.
The circular fibres (sphincter of the pupil) surround the margin of the pupil on
the posterior surface of the iris, like a sphincter, forming a narrow band, about
one-thirtieth of an inch in width; those near the free margin being closely
aggregated ; those more external somewhat separated, and forming less complete
circles. The radiating fibres (dilator of the pupil) converge from the circum-
ference towards the centre, and blend with the circular fibres near the margin
of the pupil.
The pigment-cells are found in the stroma of the iris, and also as a distinct
layer on its anterior and posterior surfaces. In the stroma, the cells are rami-
fied, and contain yellow or brown pigment, according to the color of the eye.
On the front of the iris, there is a single layer of oval or rounded cells, with
branching offsets. On the back of the iris, there are several layers of small
round cells, filled with dark pigment. This layer is continuoas with the pig-
mentary covering of the ciliary processes.
The arteries of the iris are derived from the long and anterior ciliary, and from
the vessels of the ciliary processes,
Membrana pupillaris. In the foetus^ the pupil is closed by a delicate, trans-
parent, vascular membrane, the membrana pupillaris, which divides the space
in which the iris is suspended into two distinct chambers. This membrane
contains numerous minute vessels continued from the margin of the iris to those
on the front part of the capsule of the lens. These vessels have a looped
arrangement, converging towards each other without anastomosing. During
the seventh or eighth month the membrane begins to disappear, by its gradual
absorption from the centre towards the circumference, and at birth only a few
fragments remain. It is said sometimes to remain permanent, and produce
blindness.
The Ciliary ligament is a narrow ring of circular fibres, about one-fortieth of
an inch thick, and of a whitish color: it serves to connect the external and
middle tunics of the eye. It is placed around the circumference of the iris, at
its point of connection with the external layer of the choroid, the cornea, and
sclerotic. Its component fibres are delicate, and resemble those of elastic tissue.
At its point of connection with the sclerotic a minute canal is situated between
the two, called the sinus circularis iridis.
The Ciliary muscle (Bowman) consists of unstriped fibres : it forms a grayish,
semitransparent, circular band, about one-eighth of an inch broad, on the outer
surface of the fore part of the choroid. It is thickest in front, and gradually
becomes thinner behind. Its fibres are soft, of a yellowish-white color, longitu-
dinal in direction, and arise at the point of junction of the cornea and sclerotic.
Passing backwards, they are attached to the choroid, in front of the retina, and
correspond by their inner surface to the plicated part of the former membrane.
Internal to the radiating fibres, and to some extent unconnected with them, are
bands of circular fibres, sometimes called the "ring muscle" of Miiller. The
Ciliary muscle is admitted to be the chief agent in accommodation, i. e., in-
adjusting the eye to the vision of near objects. Mr. Bowman believed that this
was effected by its compressing the vitreous bod}^ and so causing the lens to
advance ; but the view which now prevails is that the contraction of the muscle
720
ORGANS OF SENSE.
bj drawing on the ciliary processes compresses tlie lens, increasing the curvature
of its anterior surface, and causing the iris to advance. The pupil is at the
same time slightly contracted.^
The Retina may be exposed by carefully removing the choroid from its
external surface. It is a delicate nervous membrane, upon the surface of which
the images of external objects are received. Its outer surface is in contact with
the pigmentary layer of the choroid; its inner surface with the vitreous body.
Behind, it is continuous with the optic nerve; it gradually diminishes in thick-
ness from behind forwards ; and, in front, extends nearly as far forwards as the
ciliary ligament, where it terminates by a jagged margin, the or a serrata. It
is soft, and semitransparent, in the fresh state; but soon becomes clouded,
opaque, and of a pinkish tint. Exactly in the centre of the posterior part of
the retina, and at a point corresponding to the axis of the eye, in which the
sense of vision is most perfect, is a round, elevated, yellowish spot, called, after
its discoverer, the yellow spot, or lirnbus luteus, of Sommerring; having a central
depression at its summit, the fovea centralis. The retina in the situation of
the fovea centralis is exceedingly thin ; so much so, that the dark color of the
choroid is distinctly seen through it ; so that it presents more the appearance
of a foramen, and hence the name "foramen of Sommerring" at first given to
it. It exists only in man, the quadrumana, and some saurian reptiles. Its use
is unknown. About one-tenth of an inch to the inner side of the yellow spot,
is the point of entrance of the optic nerve ; the arteria centralis retinse piercing-
its centre. This is the only part of the surface of the retina from which the
power of vision is absent.
Fig. 403. — The Arteria Centralis Eetinae, Yellow Spot, etc., the anterior Half of the
Eyeball beiag removed. (Enlarged.)
Sclerofce
Choroid
Seti/ia
Structure. The retina is composed of three layers, together with bloodvessels :
External or columnar layer (Jacob's membrane).
Middle or granular layer.
Internal or nervous layer.
Tlic bloodvessels do not form a distinct layer; they ramify in the substance
of tlic internal layer, extending, however, as far as the internal granular stratum
of the middle layer.
The external^ or Jarolh memlrane^ is exceedingly tliin, and can bo detached
from iho external sni-f;i(;e of the retina, l)^ tlie linndlc of the scalpel, in the form
' Snc! nxplanalioii and diiitrram in I'owcr'.s " llliislratioiis of Koiiic of Uu; rrincii)al Diseases of
the Eye," p. 5'JO.
THE EETINA.
721
of a flocculent film. It is thicker beliind tlian in front, and consists of rod-like
bodies of two kinds: 1, Columnar rods^ solid, nearly of uniform size, and
arranged perpendicularly to tlie surface. 2. Bulbous particles^ or cones, wkicli
are interspersed at regular intervals among the former ; these are conical or
flask-shaped, their broad ends resting upon the membrana limitans externa, the
narrow pointed extremity being turned towards the choroid; they are not
solid, like the columnar rods, but consist of an external membrane with fluid
contents. By their deep ends, both kinds are joined to the fibres of Mliller.
The layer of the rods and cones is separated from the granular layer of the
retina by a transparent structureless cribriform membrane, the memhrana lioni-
tans externa.
Fiir. 404.
Fig. 405.
=^^=~^m"
Vertical sections of tlie human, retina,. Fig. 40-1, half an inch from the entrance of the optic nerve. Fig. 403 close
to the latter. 1. Layer of rods and cones {colxi,mnar layer), bounded underneath by the Membrana limitans externa.
2. External granular layer. 3. Intergranularlaycr. Internal granular layer. Molecular layer. 6. Layer of the gan-
glion-cells. 7. Expansion of optic fibres. 8. Sustentacular fibres of Miiller. 9. Their attachment to the membrana
limitans interna.
The middle or granular layer forms about one-third of the entire thickness of
the retina. It consists of two laminae of rounded or oval nuclear particles, sepa-
rated from each other by an intermediate (intergranular) lamina, which is trans-
parent, finely fibrillated, and contains no bloodvessels. The outermost lamina
is the thicker, and its constituent particles are globular. These particles are in
connection with the bases of the rods and cones by fibres passing through the
m.embrana limitans externa, and are therefore divided into " rod-granules" and
" cone-granules." The innermost lamina is the thinner ; its component particles
are flattened, looking like pieces of money seen edgeways ; hence it has been
called, by Bowman, the nummular layer. Examined more closely these cells
are seen to be bipolar, i. e. each sends off a fine process outwards through the
intergranular layer, and another inwards through the molecular layer to reach
the expansion of the optic nerve.
The internal or nervous layer is a thin semitransparent membrane, consisting
essentially of an expansion of the terminal fibres of the optic nerve and nerve-
cells. This layer is subdivided into three. The most external is the molecular,
or finely granular layer, presenting, as described by Frey, very much the appear-
ance of tlie delicate molecular matter found in the gray substance of the brain
and spinal cord. The fibres of the nervous layer pass below through this layer,
46
722 ORGANS OF SENSE.
probably to be continiTons witli the nuclei of tlie rods and cones. Internal to the '
molecular lajer is tlie layer of tlie ganglion- cells, or cellular layer. These are
multipolar cells, similar to those 'of other nervous centres, and the processes
from them pass on the one hand to the molecular layer, and on the other, to the
fibrous layer, or expansion of the optic nerve. This ganglionic layer is deepest
at the macula lutea. Finally, lying on the membrana limitans interna is the
fibrous layer or proper expansion of the optic nerve. The nerve-fibres which
form this layer differ from the fibres of the optic nerve in this respect : they lose
their dark outline, and their tendency to become varicose ; and consist only of
the central part, or axis, of the nerve tubes. The mode of termination of the
nerve-fibres is unknown. According to some observers, they terminate in loops ;
according to others, in free extremities. Eecent observers have stated that some
of the nerve-fibres are continuous with the caudate prolongations of the nerve-
cells external to the fibrous layer.
An extremely thin and delicate structureless membrane lines the inner surface
of the retina, and separates it from the vitreous body ; it is called the tnemhrana
limitans interna.
The radiating fibres of the retina., described by Heinrich Miiller, consist of
extremely fine fibrillated threads, which are connected externally with each of
the rods of the columnar layer, of which they appear to be direct continuations,
and, passing through the entire substance of the retina, are united to the outer
surface of the membrana limitans interna. In their course through the retina,
they become connected with the nuclear particles of the granular layer, or (as
described by Schultze) nuclei exist in the fibres in this situation, and they give
off" branching processes most easily demonstrated in the granular layer, by means
of which they communicate with each other ; as they approach the fibrous expan-
sion of the optic nerve, they are collected into bundles, which pass through the
areolce between its fibres, and are finally attached to the inner surface of the
membrana limitans interna, where each fibre terminates in a triangular enlarge-'
ment.
The arteria centralis retinse and its accompanying vein pierce the 023tic nerve,
and enter the globe of the eve through the porus opticus. It immediately di-
vides into four or five branches, which at first run between the hyaloid mem-
brane and the nervous layer ; but they soon enter the latter membrane, and
form a close capillary network in its substance. At the ora serrata, they termi-
nate in a single vessel which bounds the terminal margin of the retina.
The structure of the retina at the yellow spot presents some modifications.
Jacob's membrane is thinner, and of its constituents only the cones are present ;
but they are small, and more closely aggregated than in any other part. The
granular layer is absent over the fovea centralis. Of the two elements of the
nervous layer, the nerve-fibres extend only to the circumference of the spot ;
but the nerve-cells cover its entire surface. The radiating fibres are found at
the circumference, and here only extend to the inner strata of the granular layer.
Of the capillary vessels, the larger branches pass round the spot ; but the smaller
capillaries meander through it. The color of the spot appears to imbue all the
layers, except Jacob's membrane ; it is of a rich yellow, deepest towards the
centre, and does not appear to consist of pigment-cells, but resembles more a
staining of the constituent parts.
HUMO-RS OF THE EyE.
The Aqueous Humor cf)rnplo1ol3^ '"'^^^ ^1"^ anterior and posterior chambers oC
the eyeball. It is small in rpiantity (scarcely exceeding, according to Petit, four
or five grains in weight), has an alkaline reaction, in composition is little more
than Avater, loss tlian one-lifticlh of its weight being solid matter, chiefly chloride
of sodium.
THE LENS. 723
Tlie anterior chamler is the space bounded in front by tlie cornea; beliind, by
the front of the iris and ciliary ligament.
The posterior chamher^ smaller than the anterior, is bounded in front by the
iris; behind, by the capsule of the lens and its suspensory ligament, and the
ciliary processes.
In the adult, these two chambers communicate through the pupil ; but in the
fcetus in the seventh month, when the pupil is closed by the membrana papil-
laris, the two chambers are quite separate.
It has been generally supposed that the two chambers are lined by a distinct
membrane, the secreting membrane of the aqueous humor, analogous in struc-
ture to that of a serous sac. An epithelial covering can, however, only be found
on the posterior surface of the cornea. That the two chambers do, however,
secrete this fluid separately, is shown by its being found in both spaces before
the removal of the membrana pupillaris. It is probable that the parts concerned
in the secretion of the fluid, are the posterior surface of the cornea, both surfaces
of the iris, and the ciliary processes.
ViTREous Body.
The Vitreous Body forms about four-fifths of the entire globe. It fills the
concavity of the retina, and is hollowed in front for the reception of the lens
and its capsule. It is perfectly transparent, of the consistence of thin jelly, and
consists of an albuminous fluid inclosed in a delicate transparent membrane, the
hyaloid. This membrane invests the outer surface of the vitreous body; it is
intimately connected in front with the suspensory ligament of the lens; and is
continued into the back part of the capsule of the lens. It has been supposed,
by Hannover, that from its inner surface numerous thin lamella are prolonged
inwards in a radiating manner, forming spaces in which the fluid is contained.
In the adult, these lamellee cannot be detected even after careful microscopic
examination; but in the foetus a peculiar fibrous texture pervades the mass, the
fibres joining at numerous points, and presenting minute nuclear granules at
their point of junction. The fluid from the vitreous body resembles nearly
pure water; it contains, however, some sadts, and a little albumen.
In i]ie foetus^ the centre of the vitreous humor presents a tubular canal through
which a minute artery passes along the vitreous body to the capsule of the lens.
In the adult, no vessels penetrate its substance; so that its nutrition must be
carried on by the vessels of the retina and ciliary processes, situated upon its
exterior.
Crystalline Lens and its Capsule.
The Crystalline Lens, inclosed in its capsule, is situated immediately behind
the pupil, in front of the vitreous body, and surrounded by the ciliary processes,
which slightly overlap its margin.
The capsule of the lens is a transparent, highly elastic, and brittle membrane,
which closely surrounds the lens. It rests, behind, in a depression in the fore
part of the vitreous body ; in front, it forms part of the posterior chamber of
the eye; and it is retained in its position chiefly by the suspensory ligament of
the lens. The capsule is much thicker in front than behind, structureless in
texture ; and when ruptured, the edges roll up with the outer surface innermost,
like the elastic lamina of the cornea. The lens is connected to the inner surface
of the capsule by a single layer of transparent, polygonal, nucleated cells. These,
after death, absorb moisture from the fluids of the eye; and, breaking down,
form the liquor Morgagni.
In the foetus, a small branch from the arteria centralis retinee runs forwards,
as already mentioned, through the vitreous humor to the posterior part of the
capsule of the lens, where its branches radiate and form a plexiform network.
724
ORGANS OF SENSE,
wKicli covers its surface, and they are continuous round tlae margin of the cap-
sule with the vessels of the pupillary membrane, and with those of the iris. In
the adult no vessels enter its substance.
The lens is a trans23arent, double-convex body, the convexity being greater on
the posterior than on the anterior surface. It measures about a third of an inch
in the transvere diameter, and about one-fourth in the antero-posterior. It con-
sists of concentric layers, of which the external n the fresh state are soft and
easily detached; those beneath are firmer, the central ones forming a hardened
nucleus. These lamina are best demonstrated by boiling, or immersion in alcohol.
The same reagents demonstrate that the lens con-
Fig. 406.-The Crystalline Lens, gists of three triangular segments, the sharp ed^es
liai-dened and divided. ^ i ■ i t . t . i .i , .1 i
(Eulare-ed.) ^^ which are directed towards the centre, the bases
towards the circumference. The laminae consist of
minute parallel fibres, which are hexagonal prisms,
the edges being dentated, and the dentations fitting
accurately into each other ; their breadth is about
g-Q-'^oth of an inch. They run from the pole on one
side of the lens to the equator on the other, so that
the fibres which are longest in front are shortest
behind and vice versa. There are also other fibres,
which are found chiefly in the equatorial region
and at the surface of the lens, which present nuclei,
and are of a flattened form. Their nuclei form a layer (nuclear layer) on the
surface of the lens, most distinct towards its circumference. The meridians, or
lines of junction of the three segments, are formed of an amorphous granular
substance, which sometimes becomes opaque, when the lines are seen forming
a distinct star on the lens.
The changes produced in the lens hy age.^ are the following : —
In the foetus.^ its form is nearly spherical, its color of a slightly reddish tint, it
is not perfectly transparent, and is so soft as to break down readily on the
slightest pressure.
In the adult^ the posterior surface is more convex than the anterior; it is
colorless, transparent, and firm in texture.
In old age^ it becomes flattened on both surfaces, slightly opaque, of an amber
tint, and increases in density.
The suspensory ligament of the lens is a thin, transparent, membranous struc-
ture, placed between the vitreous body and the ciliary processes of the choroid;
it connects the anterior margin of the retina with the anterior surface of the
lens near its circumference. It assists in retaining the lens in its position. Its
outer surface presents a number of folds or plaitings, in which the correspond-
ing folds of the ciliary processes are received. These plaitings are arranged
round the lens in a radiating form, and are stained by the pigment of the ciliary
processes. The suspensory ligament consists of two layers, which commence
behind at the ora serrata. The external, a tough, milky, granular membrane,
covers the inner surface of the ciliary processes, and extends as far forwards as
their anterior free extremities. The inner layer, an clastic, transparent, fibro-
membranous structure, extends as far forwards as the anterior surface of the
capsule of the lens, near its circumference. That portion of this membrane
which intervenes between the ciliary processes and the capsule of the lens, forms
part of the boundary of the posterior chamber of the eye. The posterior sur-
face of this layer is turned towards the hyaloid membrane, being separated from
it at the cirgumff^rence of the lens by a space called llie canal of Petit.
The canal of Pelit is above one-tenth of an inch wide. It is bounded in front
by the suspensory iigamcnt; behind, by the hyaloifl membrane, its base being
formed by the capsule of the lens. When inflated witli air, it is sacculated at
intervals, owing to the foldings on its anterior surface.
APPENDAGES OF THE EYE. 725
The Vessels of the globe of the eye are the short, long, and anterior cihary
arteries, and the arteria centrahs retinse.
The short ciliary arteries pierce the back part of the sclerotic, round the
entrance of the optic nerve, and divide into branches which run parallel with
the axis of the eyeball : they are distributed to the middle layer of the choroid,
and to the ciliary processes.
The long ciliary arteries^ two in number, pierce the back part of the sclerotic,
and run forward, between that membrane and the choroid, to the Ciliary muscle,
where they each divide into an upper and lower branch ; these anastomose, and
form a vascular circle round the outer circumference of the iris ; from this
circle branches are given off, which unite, near the margin of the pupil, in a
smaller vascular circle. These branches, in their course, supply the muscular
structure.
The anterior ciliary arteries^ five or six in number, are branches of the
muscular and lachrymal branches of the ophthalmic. They pierce the eyeball,
at the anterior part of the sclerotic, immediately behind the margin of the
cornea, and are distributed to the ciliary processes, some branches joining the
greater vascular circle of the iris.
The arteria centralis retinse has been already described.-
The veins^ usually four in number, are formed mainly by branches from the
surface of the choroid. They perforate the sclerotic, midway between the cornea
and the optic nerve, and end in the ophthalmic vein.
The nerves of the eyeball^ are the optic, the long ciliary nerves from the nasal
branch of the ophthalmic, and the short ciliary nerves from the ciliary ganglion.
Appendages of the Eye.
The Appendages of the Eye {tutamina oculi) include the eyebrows, the eyelids,
the conjunctiva, and the lachrymal apparatus, viz., the lachrymal gland, the
lachrymal sac, and the nasal duct.
The eyebrows (supercilia) are two arched eminences of integument, which sur-
mount the upper circumference of the orbit on each side, and support numerous
short, thick hairs, directed obliquely on the surface. In structure, the eyebrows
consist of thickened integument, connected beneath with the Orbicularis palpe-
brarum, Corrugator supercilii, and Occipito-frontalis muscles. These muscles
serve, by their action on this part, to control to a certain extent the amount
of light admitted into the eye.
The eyelids [palpebrse) are two thin, movable folds, placed in front of the
eye, protecting it from injury by their closure. The upper lid is the larger,
and the more movable of the two, and is furnished with a separate elevator
muscle, the Levator palpebrse superioris. When the eyelids are opened, an
elliptical space [fissura palpebrarum) is left between their margins, the angles
of which correspond to the junction of the upper and lower lids, and are called
canthi.
Tlie outer cantlius is more acute than the inner, and the lids here lie in close
contact with the globe ; but the inner canthus is prolonged for a short distance
inwards, towards the nose, and the two lids are separated by a triangular space,
the lacus lacrymalis. At the commencement of the lacus lacrymalis, on the
margin of each eyelid, is a small conical elevation, the lachrymal papilla^ or
tubercle, the apex of which is pierced by a small orifice, the punctum lacrymale^
the commencement of the lachrymal canal.
Structure of the eyelids. The eyelids are composed of the following structures,
taken in their order from without inwards : —
Integument, areolar tissue, fibres of the Orbicularis muscle, tarsal cartilage,
fibrous membrane. Meibomian glands, and conjunctiva. The upper lid has, in
addition, the aponeurosis of the Levator palpebrse.
"26
ORGANS OF SENSE.
The integument is extremely tliin, and continuous at the margin of tlie lids
with the conjunctiva.
The subcutaneous areolar tissue is very lax and delicate, seldom contains any
fat, and is extremely liable to serous infiltration.
ilYxQ fibres of the Orbicularis muscle^ where they cover the palpebree, are thin,
pale in color, and possess an involuntary action.
The tarsal cartilayes are two thin elongated plates of fibro-cartilage, about an
inch in length. They are placed one in each lid, contributing to their form and
support.
The superior, the larger, is of a semilunar form, about one-third of an inch in
breadth at the centre, and becoming gradually narrowed at each extremitj-.
Into the upper border of this cartilage the aponeurosis of the Levator palpebrfe
is attached.
The inferior tarsal cartilage, the smaller, is thinner, and of an elliptical form.
The/ree, or ciliary margin of the cartilages is thick, and presents a perfectly
straight edge. The attached, or orbital margin, is connected to the circum-
ference of the orbit by the fibrous membrane of the lids. The outer angle of
each cartilage is attached to the malar bone by the external palpebral or tarsal
ligament. The inner angles of the two cartilages terminate at the commence-
ment of the lacus lachrymalis, being fixed to the margins of the orbit by the
tendo oculi.
The fibrous ine/mbrane of the lids, or tarsal ligament, is a layer of fibrous
membrane, beneath the Orbicularis, attached, externally to the margin of the
orbit, and internally to the orbital margin of the lids. It is thick and dense at
the outer part of the orbit, but becomes thinner as it approaches the cartilages.
This membrane serves to support the eyelids^ and retams the tarsal cartilages
in their position.
Fig. 407. — The i\Ieibomian Glanrls, etc., seen from the Inner Surface
of the Eyelids.
Xttpflfymalu
The Meibom.ian glands (Fig. 407) are situated u|)on the inner snrfiico of the
eyelids, between the tarsal cartilages and conjunctiva, and may be distinctly
scon through the mucous membrane on everting the eyelids, presenting the
appearance of parallel strings of pearls. They are about thirty in number in
the upper, cartilage, and somewhat fewer in the lower. They are embedded in
grooves in the inner surface of the cartilages, and correspond in length with the
breadth of cacli cartilage; they are, consequently, longer in the upper than in
the lower eyelid. Tlicir ducts open on the free margin of the lids by minute
foramina, Avhicli correspond in ininibfr to the follicles. These glands are a
variety of the cutaneous sebaceous glands, each consisting of a single straight
LACHRYMAL APPAEATUS. 727
tube or follicle, liaving a ctecal termination, into wliicli open a number of small
secondary follicles. The tubes consist of basement membrane, covered bj a
layer of scaly epitlielium ; tbe cells are charged with sebaceous matter, wliicli
constitutes the secretion. The peculiar parallel arrangement of these glands
side by side forms a smooth layer, adapted to the surface of the globe, over
which they constantly glide. The use of their secretion is to prevent adhesion
of the lids.
The eyelashes {cilia) are attached to the free edges of the eyelids; they are
short, thick, curved hairs, arranged in a double or triple row at the margin of
the lids : those of the upper lid, more numerous and longer than the lower,
curve upwards ; those of the lower lid curve downwards, so that they do not
interlace in closing the lids.
The conjunctiva is the mucous membrane of the eye. It lines the inner surface
of the eyelids, and is reflected over the fore part of the sclerotic and cornea. In
each of these situations, its structure presents some peculiarities.
The palpebral portion of the conjunctiva is thick, opaque, highly vascular, and
covered with numerous papillse, which, in the disease called granular lids,
become greatly hypertrophied. At the margin of the lids, it becomes con-
tinuous with the lining membrane of the ducts of the Meibomian glands, and
through the lachrymal canals, with the lining membrane of the lachrymal sac
and nasal duct. At the outer angle of the upper lid, it may be traced along
the lachrymal ducts into the lachrymal gland; and at the inner angle of the
eye, it forms a semilunar fold, the plica, semilunaris. The folds formed by the
reflection of the conjunctiva from the lids on to the eye are called the superior
and inferior palpebral folds^ the former- being the deeper of the two. Upon the
sclerotic^ the conjunctiva is loosely connected to the globe: it becomes thinner,
loses its papillary structure, is transparent, and only slightly vascular in health.
Upon the cornea^ the conjunctiva is extremely thin and closely adherent, and
no vessels can be traced into it in the adult in a healthy state. In the fcetus^
fine capillary loops extend, for some little distance forwards, into this mem-
brane; but in the adult, they pass only to the circumference of the cornea. The
deeper parts of the palpebral conjunctiva present, according to Ilenle, a con-
siderable proportion of lymphoid tissue. Lymphatics arise in the conjunctiva
in a delicate zone around the cornea, from which the vessels run to the ocular
conjunctiva;
Mucous glands are described by Ilenle in the palpebral sinus, chiefly on the
upper lid, and glands called "trachoma glands," which are analogous to the
lymphoid follicles, and have the same relation to the lymph-spaces already
spoken of. A large patch of these, strongly resembling one of Peyer's patches,
is described by Frey as found in the under eyelid of the ox. Tactile corpuscles
are found in the epithelium of the conjunctiva of the eyelids, and "beaker-cells"
have been described there.
The caruncula lacrymalis is a small, reddish, conical-shaped body, situated
at the inner canthus of the eye, and filling up the small triangular space in this
situation, the lacus lacrymalis. It consists of a cluster of follicles similar in
structure to the Meibomian, covered with mucous membrane, and is the source
of the whitish secretion which constantly collects at the inner angle of the eye.
A few slender hairs are attached to its surface. On the outer side of the
caruncula is a slight semilunar fold of mucous membrane, the concavity of '
which is directed towards the cornea: it is called the plica semilunaris. Between
its two layers is found a thin plate of cartilage. This structure is considered
to be the rudiment of the third eyelid in birds, the memhrana nictitans.
Lacheymal Appakatus. (Fig. 408.)
The Lachrymal Apparatus consists of the lachrymal gland, which secretes
the tears, and its excretory ducts, which convey the fluid to the surface of the
728 ORGANS OF SENSE.
eye. This fluid is carried away bj the lachrymal canals into the lachrymal
sac, and along the nasal duct into the cavity of the nose.
The lachrymal gland is lodged in a depression at the outer angle of the orbit,
on the inner side of the external angular process of the frontal bone. It is of
an oval form, about the size and shape of an almond. Its upper convex surface
is in contact with the periosteum of the orbit, to which it is connected by a few
fibrous bands. Its under concave surface rests upon the convexity of the eye-
ball, and upon the Superior and External recti muscles. Its vessels and nerves
enter its posterior border, whilst its anterior margin is closely adherent to the
back part of the upper eyelid, and is covered, on its inner surface, by a reflection
of the conjunctiva. This margin is separated from the rest of the gland by a
single depression, hence it is sometimes described as a separate lobe, called the
Fig. 408. — The Laclirymal Apparatus. Right Side.
palpebral jjortion of the gland. In structure and general appearance the lachry-
mal resembles the salivary glands. Its ducts, about seven in number, run
obliquely beneath the mucous membrane for a short distance, and separating
from each other, open by a series of minute orifices on the upper and outer half
of the conjunctiva, near its reflection on to the globe. These orifices are
arranged in a row. so as to disperse the secretion over the surface of the mem-
brane.
The lachrymal canals commence at the minute orifices, ptincta lacrymalia,
seen on the margin of the lids, at the outer extremity of the lacus lacrymalis.
They commence on the summit of a slightly elevated papilla, the papilla lacry-
malis, and lead into minute canals, the canaliculi, which proceed inwards to
terminate in the lachrymal sac. The superior canal, the smaller and longer of
the two, at first ascends, and then bends at an acute angle, and passes inwards
and downwards to the lachrymal sac. The inferior canal at first descends, and
then, a>)rnptly changing its course, passes almost horizontally inwards. They
are dense and elastic in structure, and somewhat dilated at their angle.
The laclivymal sac is the upper dilated extremity of the nasal duct, and is
lodged in a deep groove formed by the lachrymal bone and nasal process of the
superior maxillary. It is oval in form, its upper extremity being closed in and
rouruhid, whilst below it is contiinicd into the nasal duct. It is covered by the
Tensor tjirsi muscle and by a fibrous cx])ansion derived from the tendo oculi,
which is attached to the ridge on the lachrymal bone. In structure it consists
of a fibrous clastic coat, lined internally by mucous membrane: the latter being
continuous, through the canaliculi, Avith the mucous lining of the conjunctiva,
and through the nasal duct with the pituitary membrane of the nose.
EXTERNAL EAR.
729
The nasal duct is a membranous canal, about three-quarters of an inch in
length, which extends from the lower part of the lachrymal sac to the inferior
meatus of the nose, where it terminates by a somewhat expanded orifice, pro-
vided with an imperfect valve formed by the mucous, membrane. It is con-
tained in an osseous canal, formed by the superior maxillary, the lachrymal,
and the inferior turbinated bones, is narrower in the middle than at each ex-
tremity, and takes a direction downwards, backwards, and a little outwards.
It is lined bj mucous membrane, which is continuous below with the pituitary
lining of the nose. In the canaliculi, this membrane is provided with scaly
epithelium; but in the lachrymal sac and nasal duct, the epithelium is ciliated
as in the nose.
The Eae. :
The organ of hearing has three parts: the external ear, the middle ear or
tympanum, and the internal ear or labyrinth.
Fig. 409. — The Pinna or Auricle.
Outer Surface.
External Ear.
The External Ear consists of an expanded portion named pinna, or auricle, and
the auditory canal, or meatus. The former serves to collect the vibrations of
the air by which sound is produced, and the latter conducts those vibrations to
the tympanum.
The -pinna or auricle (Fig. 409) is formed by a layer of cartilage, covered with
integument, and connected to the commencement of the auditory canal: it is of
an ovoid form, its surface uneven, with its
larger end directed upwards. Its outer surface
is irregularly concave, directed slightly for-
wards, and presents numerous eminences and
depressions which result from the foldings of
its fibro-cartilaQ;:inous element. To each of
these names have been assigned. Thus, the
external prominent rim of the auricle is called
the helix. Another curved prominence parallel
with, and in front of the helix, is called the
antihelix] this bifurcates above, so as to inclose
a triangular depression, the fossa of the anti-
helix. The narrow curved depression between,
the helix and antihelix is called i\iQ fossa of the
helix (^ fossa inno'minata^ scaphoidea)] the anti-
helix describes a curve round a deep, capacious
cavity, the concha^ which is partially divided
into twe parts by the commencement of the
helix. In front of the concha, and projecting
backwards over the meatus, is a small pointed
eminence, the tragus ; so called from its being
generally covered, on its under surface, with a
tuft of hair, resembling a goat's beard. Opposite the tragus, and separated from
it by a deep notch {incisura intertragica)^ is a small tubercle, the antitragus.
Below this is the lobule, composed of tough areolar and adipose tissue, wanting
the firmness and elasticity of the rest of the pinna.
Structure of the pinna. The pinna is composed of a thin plate of yellow
cartilage, covered with integument, and connected to the surrounding parts by
ligaments, and a few muscular fibres.
The integument is thin, closely adherent to the cartilage, and furnished with
sebaceou.s glands, which are most numerous in the concha and scaphoid fossa.
The cartilage of the pinna consists of one single piece ; it gives form to this
730
ORGANS OF SENSE.
part of tlie ear, and upon its surface are found all the eminences and depressions
above described. It does not enter into the construction of all parts of the
auricle; thus it does not form a constituent part of the lobule; it is deficient,
also, between the tragus and beginning of the helix, the notch between them
being filled up bj dense fibrous tissue. It presents several intervals or fissures
in its substance, which partially separate the different parts. The fissure of the
helix is a short vertical slit, situated at the fore part of the pinna, immediately
behind a small conical projection of cartilage, opposite the first curve of the
helix (process of the helix). Another fissure, the fissure of the tragus, is seen
upon the anterior surface of the tragus. The antihelix is divided below, by a
deep fissure, into two parts: one part terminates by a pointed, tail-like extremity
(processus caudatus)\ the other is continuous with the anti tragus. The cartilage
of the pinna is very pliable, elastic, of a yellowish color, and similar in structure
to the cartilages of the nose.
The ligaments of the pinna consist of two sets: 1. Those connecting it to the
side of the head. 2. Those connecting the various parts of its cartilage together.
•The former, the most important, are two in number, anterior and posterior.
The anterior ligament extends from the process of the helix to the root of the
zygoma. The posterior ligament passes from the posterior surface of the concha
to the outer surface of the mastoid process of the temporal bone. A few fibres
connect the tragus to the root of the zygoma.
The ligaments connecting the various parts of the cartilage together are also
two in number. Of these, one is a strong fibrous band, stretchiug across from
the tragus to the commencement of the helix, completing the meatus in front,
and partly encircling the boundary of the concha ; the other extends between the
concha and the processus caudatus.
Fig. 410.— The Muscles of the Piuua.
The m,iisrj,es of the pinna (Fig. 410), like the ligaments, consist of two sets:
1. Those wliich connect it witli the side of lho liead, moving the phma as a
whole, viz., the Attollcns, Attrahcns, and Eotrahens aui-em (p. 841) ; and 2. The
AUDITORY CANAL.
731
proper mnscles of the pinna, wliicli extend from one part of tlie auricle to
another. These are, the
Helicis major. Antitragicus.
Helicis minor. Transversus auriculse.
Tragicus. Obliquus auris.
The Helicis major is a narrow vertical band of muscular fibres, situated upon
the anterior margin of the helix. It arises, below, from the tubercle of the
helix, and is inserted into the anterior border of the helix, just where it is about
to curve backwards. It is pretty constant in its existence.
The Helicis minor is an oblique fasciculus, attached to that part of the helix
which commences from the bottom of the concha.
The Tragicus is a short, flattened band of muscular fibres situated upon the
outer surface of the tragus, the direction of its fibres being vertical.
The Antitrarjicus arises from the outer part of the autitragus; its fibres are
inserted into the processus caudatus of the helix. This muscle is usually very
distinct.
The Traiisversus auriculse is placed on the cranial surface of the pinna. It
consists of radiating fibres, partly tendinous and partly muscular, extending
from the convexity of the concha to the prominence corresponding with the
groove of the helix.
The Obliquus auris (Todd) consists of a few fibres extending from the upper
and back part of the choncha to the convexity immediately above it.
The arteries of the pinna are the posterior auricular, from the external carotid ;
the anterior auricular, from the temporal; and an auricular branch from the
occipital artery.
The veins accompany the corresponding arteries.
The nerves are, the auricularis magnus, from the cervical plexus ; the posterior
auricular, from the facial; the auricular branch of the pneumogastric ; and the
auriculo-temporal branch of the inferior maxillary nerve.
The Auditory Cakal [meatus auditorius externus) extends from the bottom
of the concha to the membrana tympani (Fig. 411). It is about an inch and
Fig. 411. — A Front View of the Organ of Hearing. Eight Side.
.Malleaa
stapes
Tiu-oLTOwlaT Cj^nala
CocJilt/i
a quarter in length, its direction is obliquely forwards and inwards, and it is
slightly curved upon itself, so as to be higher in the middle than at either ex-
tremity. It forms an oval cylindrical canal, narrowest at the middle, somewhat
flattened from before backwards, the greatest diameter being in the vertical
direction at the external orifice ; but, in the transverse direction, at the tympanic
732 ORGANS OF SENSE.
end. The membrana tympani, which, occupies the termination of the meatus,
is obliquely directed, in consequence of the floor of the canal being longer than
the roof, and the anterior wall longer than the posterior. The auditory canal is
formed partly by cartilage and membrane, and partly by bone.
The cartilaginous portion is about half an inch in length, being rather less than
half the canal ; it is formed by the cartilage of the concha and tragus ; prolonged
inwards, and lirmly attached to the circumference of the auditory process. The
cartilage is deficient at its upper and back part, its place being supplied by
fibrous membrane. This part of the canal is rendered extremely movable by
two or three deep fissures {incisurm Santorini), which extend through the carti-
lage in a vertical direction.
The osseous portion is about three-quarters of an inch in length, and narrower
than the cartilaginous portion. It is directed inwards and a little forwards,
forming a slight curve in its course, the convexity of which is upwards and
backwards. Its inner end, which communicates with the cavity of the tympa-
num, is smaller than the outer, and sloped, the anterior wall projecting beyond
the posterior about two lines; it is marked, except at its upper part, by a narrow
groove for the insertion of the membrana tympani. Its outer end is dilated, and
rough, in the greater part of its circumference, for the attachment of the carti-
lage of the pinna. Its vertical transverse section is oval, the greatest diameter
being from above downwards. The front and lower parts of this canal are
formed by a curved plate of bone, which, in the foetus, exists as a separate ring
(tympanic bone), incomplete at its upper part.
The skin lining the meatus is very thin, adheres closely to the cartilaginous
and osseous portions of the tube, and covers the surface of the membrana tym-
pani, forming its outer layer. After maceration, the thin pouch of epidermis,
when withdrawn, preserves the form of the meatus. The skin near its orifice is
furnished with hairs and sebaceous glands. In the thick subcutaneous tissue of-
the cartilaginous part of the meatus are numerous ceruminous glands, which
secrete the ear-wax : their ducts open on the surface of the skin.
The arteries supplying the meatus are branches from the posterior auricular,
internal maxillary, and temporal.
The nerves are chiefly derived from the auriculo-temporal branch of the infe-
rior maxillary nerve.
Middle Ear, or Tympanum.
The Middle Bar, or Tympanum, is an irregular cavity, compressed from with-
out inwards, and situated within the petrous bone. It is placed above the jugular
fossa, the carotid canal lying in front, the mastoid cells behind, the meatus
auditorius externally, and the labyrinth internally. It is filled with air, and
communicates with the pharynx by the Eustachian tube. The tympanum is
traversed by a chain of movable bones, which connect the membrana tympani
with the labyrinth, and serve to convey the vibrations communicated to the
membrana tympani across the cavity of the tympanum to the internal ear.
The cavity of the tympanum measures about five lines from before backwards,
three lines in the vertical direction, and between two and three in the transverse,
being a little broader behind and above that it is below and in front. It is
bounded externally by the membrana tympani and meatus; internall}^, by the
outer surface of the internal car; and communicates, behind, with the mastoid
cells; and, in front, witli the Eustachian tube and canal for the Tensor tympani.
Its roof and floor are formed by thin osseous lamimc, which connect the squa-
mous and petrous portions of the temporal bone.
The roof is broad, flattened, and formed of a thin plate of bcme, which sepa-
rates the cranial and tympanic cavities.
T\\(i floor is narrow, and corrcs])onds to the jugular fossa, which lies beneath.
The oilier wall is formed by the membrana tym])ani, a small portion of bone
THE TYMPANUM
733
being seen above and below tliis membrane. It presents three small apertures :
the iter chordge posterius, the Glaserian fissure, and the iter chordae anterius.
The aperture of the iter chordx posterius is behind the aperture for the mem-
brana tympani, close to its margin, on a level with its centre; it leads into a
minute canal, which descends in front of the aqu^ductus Fallopii, and terminates
in that canal near the stjdo-mastoid foramen. Through it the chorda tympani
nerve enters the tympanum.
The Qlaserian fissure opens just above and in front of the orifice of the mem-
brana typamni; in this situation it is a mere slit, about a line in length. It gives
passage to the long process of the malleus, the Laxator tympani muscle, and
some tympanic vessels.
The aperture of the iter chordse anterius is seen just above the preceding fissure;
it leads into a canal (canal of Huguier), which runs parallel with the Glaserian
fissure. Through it the chorda tympani nerve leaves the tympanum.
Fig. 412 — View of Inner Wall of Tympanum. (Enlarged.)
Chorda Tyirpan
The internal wall of the tympanum (Fig. 412) is vertical in direction, and looks
directly outwards. It presents for examination the following parts :• — -
Fenestra ovalis.
Fenestra rotunda.
Promontory.
Eidge of the aqu^ductus Fallopii.
P^^ramid.
Opening for the Stapedius.
^\\Q fenestra ovalis is a reniform opening, leading from the tympanum into the
vestibule ; its long diameter is directed horizontally, and its convex border is
upwards. The opening in the recent state is closed by the lining membrane
common to both cavities, and is occupied by the base of the stapes. This mem-
brane is placed opposite the membrana tympani, and is connected with it by the
ossicula auditus.
'Vh.Q fenestra rotunda is an oval aperture placed at the bottom of a funnel-
shaped depression, leading into the cochlea. It is situated below and rather
behind the fenestra ovalis, from which it is separated by a rounded elevation,
the promontory ; it is closed in the recent state by a membrane (membrana
tympani secundaria^ Scarpa). This membrane is concave towards the tympa-
num, convex towards the cochlea. It consists of three layers ; the external, or
mucous, derived from the mucous lining of the tympanum; the internal, or
serous, from the lining membrane of the cochlea; and an intermediate, or fibrous
layer.
The promontory is a rounded hollow prominence, formed by the projection
outwards of the first turn of the cochlea; it is placed between the fenestra?, and
is furrowed on its surface by three small grooves, which lodge branches of the
tympanic plexus.
734 ORGANS OF SENSE.
The rounded eminence of the aquseductus Fallopii^ the prominence of the bony
canal in which the portio dura is contained, traverses the inner wall of the tym-
panum above the fenestra ovalis, and behind that opening curves nearly verti-
cally downwards along the posterior wall.
The 'pyramid is a conical eminence, situated immediately behind the fenestra
ovalis, and in front of the vertical portion of the eminence above described; it
is hollow in the interior, and contains the Stapedius muscle; its summit projects
forwards towards the fenestra ovalis, and presents a small aperture, which trans-
mits the tendon of the muscle. The cavity in the pyramid is prolonged into a
minute canal, which communicates with the aquseductus Fallopii, and transmits
the nerve which supplies the Stapedius.
The posterior ivall of the tympanum is wider above than below, and presents
for examination the
Openings of the Mastoid Cells.
These consist of one large irregular aperture, and several smaller openings,
situated at the upper part of the posterior wall; they lead into canals, which
communicate with large irregular cavities contained in the interior of the
mastoid process. These cavities vary considerably in number, size, and form ;
they are lined by mucous membrane, continuous with that covering the cavity
of the tympanum.
The anterior icall of the tympanum is wider above than below; it corresponds
with the carotid canal, from which it is separated by a thin plate of bone; it
presents for examination the
Canal for the Tensor tympani. Orifice of the Eustachian tube.
Processus cochleariformis.
The orifice of the canal for the Tensor tympani, and the orifice of the Eusta-
chian tube, are situated at the upper part of the anterior wall, being separated
from each other by a thin, delicate horizontal plate of bone, the processus
cochleariformis. These canals run from the tympanum forward, inward, and a
little downward, to the retiring angle between the squamous and petrous portion
of the temporal bone.
The canal for the Tensor tympani is the superior and the smaller of the two ;
it is rounded, and lies beneath the upper surface of the petrous bone, close to
the hiatus Fallopii. The tympanic end of this canal forms a conical eminence,
which is prolonged backwards into the cavity of the tympanum, and is per-
forated at its summit by an aperture, which transmits the tendon of the muscle
contained in it. This eminence is sometimes called the anterior pyramid. The
canal contains the Tensor tympani muscle.
The Eustachian tube is the channel through which the tympanum communi-
cates with the pharynx. Its length is from an inch and a half to two inches,
and its direction downwards, forwards, and iuAvards. It is formed partly of
bone, partly of cartilage and fibrous tissue.
The osseous portion is about half an inch in length. It commences in the
lower part of the anterior wall of the tympanum, below the processus cochleari-
formis, and gradually narrowing, terminates in an oval dilated opening, at the
angle of junction of the petrous and squamous portions, its extremity presenting
a jagged margin, whicli serves for the attachment of the cartilaginous portion.
The carlilar/inous portion, about an inch in length, is forincd of a triangular
plate of cartilage, curled upon itself, an interval l)eing left below, between the
margins of the cartilage, which is completed by fibrous tissue. Its canal is
narrow behind, wide, cxpanrlod, and somewhat trumpet-sha])ed in front, termi-
nating by an oval orifice, at the upixT ])i\v\ and side oC ihc ])liarynx, behind
tlic back ])art of the inferior meal us. Through this canal llie mucous mem-
brane of the pharynx is continuous with tliat which lines the tympanum. Th(!
mucous membrane is covered with (■.ilialcil cijithelium.
OSSICLES OF THE TYMPANUM. 735
The memhrana tympani separates tlie cavity of tlie tymiDamim from tjoe
"bottom of the external meatus. It is a thin semitransparent membrane, nearly
oval in form, somewhat broader above than below, and directed very obliquely
downwards and inwards. Its circumference is contained in a groove at the
inner end of the meatus, which skirts the circumference of this part, excepting
above. The handle of the malleus descends vertically between the inner and
middle layers of this membrane, as far down as its centre, where it is firmly
attached, drawing the membrane inwards, so that its outer surface is concave,
its inner convex.
Structure. This membrane is composed of three layers, an external (cuti-
cular), a middle (fibrous), and an internal (mucous). The cuticul'ar lining is
derived from the integument lining the meatus. ^Yiq fibrous layer consists of
fibrous and elastic tissues; some of the fibres radiate from near the centre to
the circumference; others are arranged, in the form of a dense circular ring,
round the attached margin of the membrane. The mucous lining is derived
from the mucous lining of the tympanum. The vessels pass to the membrana
tympani along the handle of the malleus, and are distributed between its layers.
Ossicles of the Tympanum. (Fig. 413.)
The tympanum is traversed by a chain of movable bones, three in number,
the malleus, incus, and stapes. The former is attached to the membrana tym-
pani, the latter to the fenestra ovalis, the incus being placed between the two,
to both of which it is connected by delicate articulations.
The Malleus^ so named from its fancied resemblance to a hammer, consists of
a head, neck, and three processes ; the handle or manubrium, the processus
gracilis, and the processus brevis.
The head is the large upper extremity of the bone ; it is oval in shape, and
articulates posteriorly with the incus, being free in the rest of its extent.
The nech is the narrow contracted part just beneath the head ; and below this
is a prominence, to which the various processes are attached.
The manubrium is a vertical process of bone, which is connected by its outer
margin with the membrana tympani. It decreases in size towards its extremity,
where it is curved slightly forwards, and flattened from within outwards.
The jDrocessus gracilis is a long and very delicate process, which passes from
the eminence below the neck forwards and outwards to the Glaserian fissure, to
which it is connected by bone and ligamentous fibres. It gives attachment to
the Laxator tympani.
The processes brevis is a slight conical projection, which springs from the root
of the manubrium, and lies in contact with the membrana tympani. Its summit
gives attachment to the Tensor tympani.
The Incus has received its name from its supposed resemblance to an anvil,
but it is more like a bicuspid tooth, with two roots, which differ in length, and
are widely separated from each other. It consists
of a body and two processus. Fig. 413.— The Small Bones of
The body is somewhat quadrilateral, but com- Jl^e Ear seen ii-o.n the Outside,
pressed laterally. Its summit is deeply concave,
and articulates with the malleus ; in the fresh state,
it is covered with cartilage and lined with synovial
membrane.
The two processes diverge from one another
nearly at right angles.
The short process, somewhat conical in shape,
projects nearly horizontally backwards, and is
attached to the margin of the opening leading into
the mastoid cells, by ligamentous fibres.
The long process, longer and more slender than
730 ORGANS OF SENSE.
tlie preceding, descends nearly vertically behind the handle of the malleus, and
bending inwards, terminates in a rounded globular projection, the os orhiculare,
or lenticular process, which is tipj^ed with cartilage, and articulates with the
head of the stapes. In the foetus the os orbiculare exists as a separate bone,
but becomes united to the long process of the incus in the adult.
The /Sta2Des^ so called from its close resemblance to a stirrup, consists of a head,
neck, two branches, and a base.
The head presents a depression, tipped with cartilage, which articulates with
the OS orbiculare.
The 7iecl\ the constricted part of the bone below the head, receives the inser-
tion of the Stapedius muscle.
The two branches {crura) diverge from the neck, and are connected at their
extremities by a flattened, oval-shaped plate {the lase)^ which forms the foot of
the stirrup, and is fixed to the margin of the fenestra ovalis by ligamentous
fibres.
Ligaments of the Ossicula. These small bones are connected with each other,
and with the walls of the tympanum, by ligaments, and moved by small mus-
cles. The articular surfaces of the malleus and incus, the orbicular process of
the incus and head of the stapes, are covered with cartilage, connected together
by delicate capsular ligaments, and lined by synovial membrane. The liga-
ments connecting the ossicula with the walls of the tympanum are three in
number, one for each bone.
The suspensory ligament of the m.aUeus is a delicate, round bundle of fibres,
which descends perpendicularly from the roof of the tympanum to the head of
the malleus.
The posterior ligament of the incus is a short, thick, ligamentous band, which
connects the extremity of the short process of the incus to the posterior wall of
the tympanum, near the margin of the opening of the mastoid cells.
The annular ligament of the stapes connects the circumference of the base of
this bone to the margin of the fenestra ovalis.
A suspensory liga^ment of the incus has been described by Arnold, descending
from the roof of the tympanum to the upper part of the incus, near its articula-
tion with the malleus.
The muscles of the tympanum are three : — -
Tensor tympani. Laxator tympani. Stapedius.
The Tensor tympani^ the largest, is contained in the bony canal, above the
osseous portion of the Eustachian tube, from which it is separated by the pro-
cessus cochleariformis. It arises from the under surface of the petrous bone,
from the cartilaginous portion of the Eustachian tube, and from the osseous
canal in which it is contained. Passing backwards, it terminates in a slender
tendon which is reflected outwards over the processus cochleariformis, and is in-
serted into the handle of the malleus, near its root. It is supplied by a branch
from the otic ganglion.
The Laxator tympani major (Scimmerring) arises from the spinous process of
the sphenoid bono, and from the cartilaginous portion of the Eustachian tube,
and passing backwards tlirough the Glascrian fissure, is inserted into the neck
of the malleus, just above the processus gracilis. It is supplied by the tympanic
branch of the facial.
The Laxator tympani minor (Sommerring) arises from the upper and back
part of the external meatus, passes forwards and inwards between the middle
and inner layers of the membrana tympani, and is inserted into the handle of the
malleus and processus brcvis.
The Laxator tympani major is now very generally T)clicvcd to be ligamentous
and not muscular, and there seems little doubt that the structure described
under the name of Laxator tympani minor is a ligament.
The Stapedius arises from the sides of a conical cavity hollowed out of the
NERVES OF THE TYMPANUM. 7S7
interior of the pyramid : its tendon emerges from the orifice at the apex of the
pyramid, and passing forwards, is inserted into the neck of the stapes. Its
surface is aponeurotic, its interior fleshy ; and its tendon occasionally contains a
slender bony spine, which is constant in some mammalia. It is supplied by a
filament from the facial nerve.
Actions. The Tensor tympani draws the membrana tympani inwards, and
thus heightens its tension. The laxator tympani draws the malleus outwards,
and thus the tympanic membrane, especially at its fore part, is relaxed. The
Stapedius depresses the back part of the base of the stapes, and raises its fore
part. It probably compresses the contents of the vestibule.
The mucous memhrane of the tympanum is thin, vascular, and continuous with
the mucous membrane of the pharynx, through the Eustachian tube. It invests
the ossicula, and the muscles and nerves contained in the tympanic cavity ;
forms the internal layer of the membrana tympani ; covers the foramem rotun-
dum ; and is reflected into the mastoid cells, which it lines throughout. In the
tympanum and mastoid cells, this membrane is pale, thin, slightly vascular, and
covered with ciliated epithelium. In the . osseous portion, of the Eustachian
tube, the membrane is thin ; but in the cartilaginous portion it is very thick,
highly vascular, covered with laminar ciliated epithelium, and provided with
numerous mucous glands.
The arteries swpijlying the tympanum are five in number. Two of them are
larger than the rest, viz., the tympanic branch of the internal maxillary, which
supplies the membrana tympani ; and the stylo-mastoid branch of the posterior
auricular, which supplies the back part of the tympanum and mastoid cells.
The smaller branches are, the petrosal branch of the middle meningeal, and
branches from the ascending pharyngeal and internal carotid.
The veins of the tympanum terminate in the middle meningeal and pharyngeal
veins and, through these, in the internal jugular.
The nerves of the tympa.num may be divided into: 1. Those supplying the
muscles; 2. Those distributed to the lining membrane ; 3. Branches communi-
cating with other nerves.
Nerves to muscles. The Tensor tympani is supplied by a branch from the otic
ganglion ; the Laxator tympani, and the Stapedius, by a filament from the facial
(Sommerring).
The nerves distributed to the lining m,emhrane are derived from the tympanic
plexus.
Communications between the following nerves take place in the tympanum:
the tympanic branch from the petrous ganglion of the glosso-pharyngeal ; a
filament from the carotid plexus; a branch which joins the great superficial
petrosal nerve from the Vidian; and a branch to the otic ganglion (small super-
ficial petrosal nerve).
The tympanic branch of the glosso-p)haryngeal (Jacobson's nerve) enters the
tympanum by an aperture in its floor, close to the inner wall, and ascends on
to the promontory. It distributes filaments to the lining membrane of the
tympanum, and divides into three branches, which are contained in grooves on
the promontory, and serve to connect this with other nerves. One branch runs
in a groove, forwards and downwards, to an aperture situated at the junction
of the anterior and inner walls, just above the floor, and enters the carotid
canal, to communicate with the carotid plexus of the sympathetic. The second
branch is contained in a groove which runs vertically upwards to an aperture
on the inner wall of the tympanum, just beneath the anterior pyramid, and in
front of the fenestra ovalis. The canal leading from this opens into the hiatus
Fallopii, where the nerve contained in it joins the great petrosal nerve.' The
third branch (small superficial petrosal) ascends towards the anterior surface of
the petrous bone; it then passes through a small aperture in the sphenoid and
temporal bones to the exterior of the skull, and joins the otic ganglion. As
47
738
ORGANS OF SENSE,
this nerve passes bj tlie gangliform enlargement of tlie facial, it has a connecting
filament with it.
The chorda tympani quits the facial near the stylo-mastoid foramen, enters
the tympanum at the base of the pyramid, and arches forwards across its cavity
between the handle of the malleus and long process of the incus, to an opening
internal to the fissura Glaseri. It is invested by a reflection of the lining mem-
brane of the tympanum.
Inteenal Bak, or Labyrinth.
The Internal Ear is the essential part of the organ, receiving the ultimate
distribution of the auditory nerve. It is called the labyrinth^ from the com-
plexity of its shape, and consists of three parts: the vestibule, semicircular
canals, and cochlea. It is formed by a series of cavities, channelled out of the
substance of the petrous bone, communicating externally with the cavity of
the tympanum, through the fenestra ovalis and rotunda ; and internally, with
the meatus auditorius internus, which contains the auditory nerve. Within the
osseous labyrinth is contained the membranous labyrinth, upon which the
ramifications of the auditory nerve are distributed.
The Vestihule (Fig. 414) is the common central cavity of communication
between the parts of the internal ear. It is situated on the inner side of the
Fig. 414. — The Osseous Labyrinth laid open. (Enlarged.)
IS
Ope-nivg pf-
^2 laaurttcs Vcstclfuh
Srt^t/e. pajigfj, through
J'Ora.iti,. T'oiu/iid,
tympanum, behind the cochlea, and in front of the semicircular canals. It is
somewhat ovoidal in shape from before backwards, flattened from side to side,
and measures about one-fifth of an inch from before l^aclcwards, as well as from
aljovc downwards, being narrower from without inwards. On its outcr^ or tym-
panic. wall, is the fenestra ovalis, closed in the recent state, by the base of the
stapes, and its annular ligament. On its inner wall, at the fore part, is a small
circular depression, /ovm hemisph erica, which is perforated, at its anterior and
inferior part, by several minute holes {macula crihrosn), for the passage of tlie
filaments of the auditory nerve; and behind this depression is a vertical ridge,
the pyramidal eminence. At llio hinder part of the inner wall is the orifice of
the wpxvcdachis veslihnU, which extends to the posterior surface of the petrous
portion of the temporal bone. It transmits a small vein, and, according to
COCHLEA. 739
some, contains a tubular prolongation of the lining membrane of tlie vestibule,
which ends in a cul-de-sac between the layers of the dura mater within the
cranial cavity. On the up'per loall or roof is a transverselj^-oval depression,
fovea seini-elli])tica.i separated from the fovea hemispherica by the pyramidal
eminence, already mentioned. Behind, the semicircular canals open into the
vestibule by live oritices. In front is a large oval opening, which communicates
with the scala vestibuli of the cochlea by a single orifice, apertura scalse vestihuli
cochleee.
The Semicirculai' Canals are three bony canals, situated above and behind the
vestibule. They are of unequal length, compressed from side to side, and
describe the greater part of a circle. They measure about one-twentieth of an
inch in diameter, and each presents a dilatation at one end, called the ampulla^
which measures more than twice the diameter of the tube. These canals open
into the vestibule by five orifices, one of the apertures being common to two
of the canals.
The superior seniicircular canal is vertical in direction, and stretches across
the petrous portion of the temporal bone, at right angles to its posterior surface ;
its arch forms a round projection on the anterior surface of the petrous bone.
It describes about two-thirds of a circle. Its outer extremity, which is ampul-
lated, commences by a distinct orifice in the upper part of the vestibule ; the
opposite end of the canal, which is not dilated, joins with the corresponding part
of the posterior canal, and opens by a common orifice with it in the back part
of the vestibule.
The posterior semicircular canal^ also vertical in direction, is directed back-
wards, nearly parallel to the posterior surface of the petrous bone : it is the
longest of the three, its ampullated end commencing at the lower and back
part of the vestibule, its opposite end joining to form the common canal already
mentioned.
The external or horizontal canal is the shortest of the three, its arch being
directed outwards and backwards ; thus each semicircular canal stands at right
angles to the other two. Its ampullated end corresponds to the upper and outer
angle of the vestibule, just above the fenestra ovalis; its opposite end opens by
a distinct orifice at the upper and back part of the vestibule.
yhe Cochlea bears some resemblance to a common snail-shell : it forms the
anterior part of the labyrinth, is conical in form, and placed almost horizontally
in front of the vestibule ; its apex is directed forwards and outwards towards
the upper and front part of the inner wall of the tympanum ; its base corresponds
with the anterior depression at the bottom of the internal auditory meatus, and
is perforated by numerous apertures, for the passage of the cochlear branch of
the auditory nerve. It measures about a quarter of an inch in length, and its
breadth towards the base is about the same. It consists of a conical-shaped
central axis, the modiolus or columella ; of a canal wound spirally round the
axis for two turns and a half, from the base to the apex ; and of a delicate lamina
{lamina spiralis) contained within the canal, which follows its windings, and
subdivides it into two.
The central axis, or modiolus, is conical in form, and extends from the base to
the apex of the cochlea. Its base is broad, corresponds with the first turn of
the cochlea, and is perforated by numerous orifices, which transmit filaments of
the cochlear branch of the auditory nerve ; the axis diminishes rapidly in size in
the second coil, and terminates within the last half-coil, or cupola, in an ex-
panded, delicate, bony lamella, which resembles the half of a funnel, divided longi-
tudinally, and is called the infundihulum ; the broad part of this funnel is directed
towards the summit of the cochlea, and blends with the last half- turn of the
spiral canal of the trochlea, the cupola. At this point the two larger scali^e of
the cochlea, the scala tympani and scala vestibuli, communicate by an opening
called the helicotrema. The outer surface of the modiolus is formed of the wall
of the spiral canal, and is dense in structure; but its centre is channelled, as far
740
ORGANS OF SENSE,
as tlie last half-coil, by numerous branching canals, wbicb transmit nervous fila-
ments in regular succession into the canal of tlie cochlea, or on to the surface of
the lamina spiralis. One of these, larger than the rest, occupies the centre of
the modiolus, and is named the tubulus centralis modioli ; it extends from the
base to the extremity of the modiolus, and transmits a small nerve and artery
{cirteria centralis modioli).
The spiral canal (Fig. 415) takes two turns and a half round the modiolus.
It is about an inch and a half in length, measured along its outer wall ; and
Fig. 415 — The Coclilea laid open. (Enlarged.)
diminishes gradually in size from the base to the summit, where it terminates
in a cul-de-sac, the cupola, which forms the apex of the cochlea. The commence-
ment of this canal is about the tenth of an inch in diameter : it diverges from
the modiolus towards the tympanum and vestibule, and presents three openings.
One, \\ie fenestra rotunda, communicates with the tympanum : in the recent state,
this aperture is closed by a membrane, the m,emhrana tympani secundaria. An-
Fig. 416. — Longitudinal Section of the Cochlea, showing the relations of the
Scalae, the Ganglion Spirals, etc.
S. V. Scala vfiHtibuli. S. T. Rcala tymp.T.iii. S. Af. Snila ni 'dia. I-. S. Li;,'!iinoiitum spiralo.
G. S. (iaiigliou Bjiiralo.
Other aportnro, of an oval form, enters the vestibule. The third is the aperture
of the afjmcdAictvs cocliJcip, leading to a minute funnel-shaped canal, which opens
on the basilar surface of iIk; petrous bone, and transmits a small vein.
The interior of the spiral canal (Fig. -116) is divided into three princijial
SCALA MEDIA. 741
canals or scalse — viz., tlie Scala tjmpani, the Scala vestibuli, and, interposed
between these, the Scala media. Projecting from the modiolus is a thin bony
process, the lamina spiralis ossea^ which consists of two thin lamellae of bone,
between which are numerons canals for the passage of nervous filaments. Near
the point where the osseous lamina is attached to the modiolus is a small canal,
denominated by Rosenthal the canalis spiralis modioli, and occupied by a swell-
ing of the cochlear nerve, in which ganglion-cells are found, the (janylion spirale,
from which the nerves pass to the osseous lamina and organ of Corti.
The osseous lamina extends only part of the distance between the modiolus
and the outer bony wall of the cochlea. Near its outei end the periosteum
swells up into an elevation which is called the limlms laminse spiralis (" denticu-
late lamina" of Todd and Bowman), and this terminates in a grooved border, the
sulcus spiralis (Fig. 417), the edges of the groove being called the labium tympa-
nicum and labium vestibulare respectively. From the labium tympanicum a
thin membrane extends over to the bony wall of the cochlea, completing the
scala tympani. This membrane is called the membrana basilaris. At its outer
attachment it swells out so as to form a thick triangular structure which was
regarded as a muscle by Todd and Bowman (cochlearis), but is now recognized
as ligamentous — -the liy amentum spirale. Betweeen the labium vestibulare and
the attachment of the membrane of Reissner, presently to be described, a very
delicate membrane extends over to the outer wall of the cochlea, running nearly
parallel to the membrana basilaris. It was described by Corti, and covers over
the organ which is called after his name, and is therefore called the membrana
tectoria or membrane of Corti. Further inwards, near the commencement of the
limbus lamina spiralis, another delicate membrane, the m,e.mbrane of Reissner,
is attached to the vestibular surface of the periosteum of the osseous lamina,
and stretches across to the outer wall of the cochlea. The canal which lies
below the osseous lamina and membrana basilaris is the scala tympani; that
which is bounded by the osseous lamina and membrane of Reissner the scala
vestibuli ; while the space between the membrane of Reissner and membrana
basilaris is generally described as the Scala media, Canalis membranacea, or
Canalis cochlese, and this is the nomenclature which will be used here. Others,
however, apply the name Canalis cochlese only to the canal lying between the
membrane of Reissner and the membrana tectoria, which contains no object for
description, while the space lying between the membrana tectoria and membrana
basilaris is described by itself as a fourth canal — the ductus cochlearis or ductus
auditorius.^ The latter is the space in which the organ of Corti^ is contained.
This organ (Fig. 417) is situated upon the membrana basilaris, and appears at
first sight as a papilla, winding spirally with the turns of this membrane
throughout the whole length of the cochlea, from which circumstance it has
been designated the papilla sjnralis. More accurately viewed, it is seen to be
composed of a series of arches roofing over the zona arcuata, estimated at over
3000 in number. The base of these arches is said to be of uniform length in
the whole of the canal. The inner limb of the arch is formed by a fibre (inter-
nal fibres or rods of Corti) somewhat swollen at either extremity. In connection
with the lower extremity is a nuclear body. The space between the internal
rod and the grooved margin of the sulcus spiralis is occupied by cylindrical
epithelium, and some of these epithelial cells are provided with hair-like pro-
cesses ("inner hair-cells"). The external limb of the arch is formed by a simi-
lar series of fibres (external fibres or rods of Corti) which are less numerous
> In reading the older descriptions of the organ of hearing, the student must bear in mind that
the membranes bounding the ductus auditorius, together with the organ contained between them,
were described together as ihe "lamina spiralis membranacea," while the membrane of Reissner
was not recognized, the parts being, in fact, as shown in the second turn of the cochlea on the
right hand of Fig. 416.
2 Oorti's original paper is in the Zeitschrift f. Wissen. Zool. iii. 109.
742
ORGANS OF SENSE,
than the internaV and the swollen upper extremities of the two rods are articu-
lated together ; the crown of the arch approaches, but does not touch, the mem-
brana tectoria. The shape of the external and internal rods of Corti is peculiar.
The internal rods terminate above in a process which exactly reproduces the
Fig. 417.— Floor of Scala Media, showing the organ of Corti, etc.
■^ MEMBRANA BASlLARISX^sCv.
^
^u.
shape of the head of the human ulna, with its sigmoid cavity, coronoid and ole-
cranon processes, while the external represent the head and bill of a swan — the
head fitting into the concavities of one or more of the internal rods (which are
more numerous than the external) while the bill rests against the phalanges of
the lamina reticularis. Lying against the external rods are epithelial cells of
various forms. Those described by Corti, and called after hira cells of Corti.,
are provided with hairs or cilia, " outer hair-cells." There are several rows of
these, alternating witli which are other epithelial cells terminating in a fine ex-
tremity above and below : these are called the cells of Deiters ; and beyond these
again are the ordinary epithelial cells of the part, gradually diminishing in size.
The reticular lamina of Kolliker is formed by several rows of "minute fiddle-
shaped cuticular structures" called phalanges., between which are holes for the
j)rojection of the outer hair-cells. The number of rows varies in different
animals with that of the outer hair-cells, being four in man. The exact termi-
nation of the nerves in the organ of Corti is not as yet determined, but there
seems no doubt that this organ is to be regarded as the " terminal apparatus of
hearing," as Henle names it.^
The scala media is closed above and below. The upper blind extremity is
attached to the cupola at the upper part of the helicotrema, the loAver end fits
into the angle at the commencement of the osseous lamina on the floor of the
vestibule. Near tliis blind extremity the scala media receives the canalis reuniens
(Fig. 418), a very delicate canal, by which the ductus cochlearis is brought into
continuity with the saccule.
The i7iner surface of the osseous labyrinth is lined by an excccdiugly thin
fibro-serous membrane, ana.logous to a ])eriosteum, from its close adhesion to the
inner surfaces of tlicse cavities, and performing the office of a serous membrane
by its free surface. It lines the vestibule, and from this cavity is continued into
the semicircular canals and the scala vestibuli of IIk; cochlea, and through the
helicotrema into the scala tympani. Two delicate tubular processes are pro-
longf,d along the arpicducts of the vestibule and cochlea, to the inner surface of
' Wiildcycr rcf'kons (iOOd of llio inner rods and 4500 of tlio ont(M- in tlie Imman cochlea. Clau-
dius say.s Ihal, there are three of lh(! inner for every two of the outer
* For further details the render is referred to Kiilliker's GcwehcJr.hre, 5th ed. ; Ilenle's Si/sf,e-
maf/sclie Analomic, or (iuaid'.s Anatomi/, edited by Sharpey, 'I'honison, and Schafer, 8lh ed.,
18TG.
MEMBRANOUS LABYRINTH
74?
the dura mater. This membrane is continued across the fenestra ovalis and
rotunda, and consequently has no communication with the hning membrane of
the tympanum. Its attached surface is rougli and fibrous, and closely adherent
to the bone; its free surface is smooth and pale, covered with a layer of epithe-
lium, and secretes a thin, limpid fluid, the aqua lahyrinthi [perilymidh [131ain-
ville], liquor Gotunnii).
The Membkanous Labyeikth.
The Membranous Labyrinth (Fig. 418) is a closed membranous sac, containing
fluid. The ramifications of the auditory nerve are distributed upon the wall of
the sac. It has the same general form as the vestibule and semicircular canals
in which it is inclosed; but is considerably smaller, and separated from their
lining membrane by the perilymph.
Fig. 418. — The Membranous Labyrinth. (Enlarged 4 diam.)
CANALIS REUNIENS
The vestibular portion consists of two sacs, the utricle and the saccule.
The utricle is the larger of the two, of an oblong form, compressed laterally
and occupies the upper and back part of the vestibule, lying in contact with the
fovea semi-elliptica. Numerous filaments of the auditory nerve are distributed
on the wall of this sac, and its cavity communicates behind with the membra-
nous semicircular canals by five orifices.
The saccule is the smaller of the two vestibular sacs ; it is globular in form,
lies in the fovea hemispherica, near the opening of the vestibular scala of the
cochlea, and receives numerous nervous filaments, which enter from the bottom
of the depression in which it is contained. Its cavity is apparently distinct from
that of the utricle.
The memhranous semicircular canals are about one-third the diameter of the
osseous canals, but in number, shape, and general form they are precisely simi-
lar; they are hollow, and open by five orifices into the utricle, one opening
being common to two canals. Their ampullae are thicker than the rest of the
tubes, and nearly fill the cavities in which they are contained.
The membranous labyrinth is held in its position by the numerous nervous
filaments distributed to the utricle, to the saccule, and to the ampulla of each
canal. These nerves enter the vestibule through the minute apertures on its
inner wall.
Structure. The wall of the membranous labyrinth is semi-transparent, and
consists of three layers. The outer layer is a loose and flocculent tissue, contain-
ing bloodvessels and numerous pigment-cells analogus to those in the choroid.
The 'middle layer^ thicker and more transparent, bears some resemblance to the
7U ORGANS OF SENSE.
hyaloid membrane, but it presents in parts marks of longitudinal fibrillation and
elongated nuclei on the addition of acetic acid. The inner layer is formed of
polygonal nucleated epithelial cells, which secrete the endolymph.
The endolymph [liquor Scarpse) is a limpid serous fluid, which fills the mem-
branous labyrinth; in composition, it closely resembles the perilymph.
The otoliths are two small rounded bodies, consisting of a mass of minute
crystalline grains of carbonate of lime, held together in a mesh of delicate fibrous
tissue, and contained in the wall of the utricle and saccule, opposite the distribu-
tion of the nerves. A calcareous material is also, according to Bowman,
sparingl}^ scattered in the cells lining the ampulla of each semicircular canal.
The Arteries of the labyrinth are the internal auditory, from the basilar or
superior cerebellar, the stylo- mastoid, from the posterior auricular, and, occa-
sionally, branches from the occipital. The internal auditory divides at the
bottom of the internal meatus into two branches, cochlear and vestibular.
The cochlear branch subdivides into from twelve to fourteen twigs, which
traverse the canals in the modiolus, and are distributed, in the form of a capil-
lary network, in the substance of the lamina spiralis.
The vestibular branches accompany the nerves, and are distributed, in the
form of a minute capillary network, in the substance of the membranous laby-
rinth.
The Veins (auditory) of the vestibule and semicircular canals accompany the
arteries, and, receiving those of the cochlea at the base of the modiolous, termi-
nate in the superior petrosal sinus.
The Auditory nerve^ the special nerve of the sense of hearing, divides, at the
bottom of the internal auditory meatus, into two branches, the coclilear and
vestibular. The trunk of the nerve, as well as the branches, contains numerous
ganglion-cells with caudate prolongations.
The vestibular nerve^ the posterior of the two, divides into three branches,
superior, middle, and inferior.
The superior vestibular branch, the largest, divides into numerous filaments,
which pass through minute openings at the upper and back part of the cul-de-
sac at the bottom of the meatus, and entering the vestibule, are distributed to
the utricle, and to the ampulla of the external and superior semicircular canals.
The middle vestibular branch consists of numerous filaments, which enter the
vestibule by a smaller cluster of foramina, placed below those above mentioned,
and which correspjrmd to the bottom of the fovea hemispherica; they are dis-
tributed to the saccule.
The inferior and smallest branch passes backwards in a canal behind the
foramina for the nerves of the saccule, and is distributed to the ampulla of the
posterior semicircular canal.
The nervous filaments enter the ampullary enlargements at a deep depression
seen on their external surface, and a corresponding elevation is seen within, the
nerve-fibres ending in loops, and in free extremities. In the utricle and saccule,
the nerve-fibres spread out, some blending with the calcareous matter, others
radiating on the inner surface of the wall of each cavity, becoming blended with
a layer of nucleated cells, and terminating in a thin fibrous film.
Tlic cocli.lear weri;e divides into numerous filaments at the base of the modiolus,
which ascend along its canal, and then, bending outwards at right angles, pass
between the plates of the bony lamina spiralis, close to its tympanic surface.
Between the plates of the spiral lamina, the nerves form a ]ilcxus, which con-
tains ganglion-cells; and from tlic margin of the osseous zone, branches of this
plexus arc distributed to llic membranous part of the septum, where they are
arranged in small, conical-sliajx'd bundles, parall(>.l with one another. The fila-
ments wliich su[)ply the a])ic,jil [jortion of the lamina spii^alis arc conducted to
this part through tlie tubulus conlralis modioli.
Organs of Digestion.
The Apparatus for the digestion of tlie food consists of the alimentary canal,
and of certain accessory organs.
The Alimentary Canal is a musculo-membranous tube, about thirty feet in
length, extending from the mouth to the anus, and lined throughout its entire
extent by mucous membrane. It has received different names in the various
parts of its course : at its commencement, the mouth, we find provision made
for the mechanical divisioli of the food (mastication), and for its admixture with
a fluid secreted by the salivary glands (insalivation) ; beyond this are the
organs of deglutition, the pharynx and the oesophagns, which convey the food
into that part of the alimentary canal (the stomach) in which the principal
chemical changes occur; in the stomach, the reduction and solution of the food
takes place; in the small intestines, the nutritive principles of the food (the
chyle) are separated, by its admixture with the bile and pancreatic fluid, from
that portion which passes into the large intestine, most of which is expelled
from the system.
Mouth.
Pharynx.
(Esophagus.
Stomach.
Alimentary Canal.
Small intestine
Large intestine
Accessory Organs.
Teeth.
i Parotid.
Salivary glands. •< Submaxillary.
( Sublingual.
i Duodenum.
I Jejunum.
( Ileum.
( Caecum.
■| Colon.
( Eectum.
Liver.
Pancreas,
Spleen.
The Mouth (Fig. 419) is placed at the commencement of the alimentary
canal; it is a nearly oval- shaped cavity, in which the mastication of the food
takes place. It is bounded, in front, by the lips ; laterally, by the cheeks and the
alveolar processes of the upper and lower jaws ; above, by the hard palate and
teeth of the upper jaw; below, by the tongue, and by the mucous membrane
stretched between the under surface of that organ and the inner surface of the
jaws, and by the teeth of the lower jaw ; behind, by the soft palate and fauces.
The mucous membrane lining the mouth is continuous with the integument at
the free margin of the lips, and with the mucous lining of the fauces behind ;
it is of a rose-pink tinge during life, and very thick where it covers the hard
parts bounding the cavity.
The Lips are two fleshy folds, which surround the orifice of the mouth,
formed externally of integument, and internally -of mucous membrane, between
which is found the Orbicularis oris muscle, the coronary vessels, some nerves,
areolar tissue, and fat and numerous small labial glands. The inner surface of
each lip is connected in the middle line to the gum of the corresponding jaw
by a fold of mucous membrane, \h.Q frsenum lahii superioris and inferioris^ the
former being the larger of the two.
The labial glands are situated between the mucous membrane and the Orbicu-
laris oris, round the orifice of the mouth. They are rounded in form, about the
(745)
746
ORGANS OF DIGESTION.
size of small peas, tlieir ducts opening by small orifices upon the mucous mem-
brane. In structure, they resemble the other salivary glands.
The Cheeks form the sides of the face, and are continuous in front with the
lips. They are composed, externally, of integument ; internally, of mucous
membrane, and, between the two, of a muscular stratum, besides a large quantity
of fat, areolar tissue, vessels, nerves, and buccal glands.
The mucous membrane lining the cheek is reflected above and below upon the
gums, and is continuous behind with the lining membrane of the soft palate.
Opposite the second molar tooth of the upper jaw is a papilla, the summit of
Fig. 419.- Sectional View of the Nose, Mouth, Pharynx, etc.
Bristle
d throuijh
Steno's dut-'t
which presents the aperture of the duct of the parotid gland. The principal
muscle of the cheek is the Buccinator; but numerous other muscles enter into
its formation, viz., the Zygomatici, Masseter, and Platysma myoidcs.
The buccal (jlands are placed between the mucous membrane and Buccinator
muscle ; they arc similar in structure to the labial glands, but smaller. Two or
tliroc of larger size than the rest, are placed between tlie Masseter and Bucci-
nator muscles, their ducts open into the inoutli, ()p])osite the last molar tooth.
Tlicy arc called 'molar (jlands.
The Gums are composed of a dense fibrous tissue, closely connected to the
periosteum of the alveolar processes, nnd surrounding the necks of the teeth.
They arc covered by smooth and vascuhir hukjous membrane, which is remarka-
ble for its limited sensibility. Around the necks of the teeth, this membrane
THE TEETH.
747
presents numerous fine papillse ; and from this point it is reflected into the
alveolus, where it is continuous with the periosteal membrane hning that
cavitj.
The Teeth.
The human subject is provided with two sets of teeth, which make their
appearance at different periods of life. The first set appear in childhood, and
are called the temporary^ deciduous^ or milk teeth. The second set, which also
appear at an early period, continue until old age, and are named permanent.
The temporary teeth are twenty in number.; four incisors, two canine, and four
molars, in each jaw.
The permanent teeth are thirty-two in number ; four incisors (two central and
two lateral), two canine, four bicuspids, and six molars, in each jaw.
General characters. Each tooth consists of three portions: the crown, or body.
Fig. 420. — The Permanent 'J'eeth. External View,
VjipeT Jaw
Molars Bicuspid t Canine
^ r —
TtI£ISOTT
Wisdom, tnoth
- Neck
ZiOit/er Jctiv
projectmg above the gum; the root, or fang, entirely concealed within the
alveolus; and the neck, the constricted portion between the other two.
_ The roots of the teeth are firmly implanted within the alveoli : these depres-
sions are lined with periosteum, which is reflected on to the tooth at the point
of the fang, and covers it as far as the neck. At the margin of the alveolus,
the periosteum becomes continuous with the fibrous structure of the gums.
Peemanent Teeth.
The Incisors, or cutting teeth, are so named from their presenting a sharp,
cutting edge, adapted for cutting the food. They are eight in number, and form
the four front teeth in each jaw.
The crown is directed vertically, is wedge-like in form, being bevelled at the
expense of its posterior surface, so as to terminate in a sharp, horizontal cutting
748 ORGANS OF DIGESTION.
edge, wbicli, before being subject to attrition, presents three small prominent
points. It is convex, smooth, and highly polished in front; sHghtly concave
behind, where it is frequently marked by slight longitudinal furrows.
The neck is constricted.
The fang is long, single, conical, transversely flattened, thicker before than
behind, and slightly grooved on each side in the longitudinal direction.
The incisors of the uj^per jaw are altogether larger and stronger than those of
the lower jaw. Thev are directed obliquely downwards and forwards. The
two central ones are larger than the two lateral, and their free edges are sharp
and chisel-like, being bevelled at the expense of their posterior edge: the root
is more rounded.
The incisors of the lower jaio are smaller than the upper: the two central
ones are smaller than the two lateral, and are the smallest of all the incisor
teeth.
The Canine Teeth (cuspidati) are four in number, two in the upper, and two
in the lower jaw ; one being placed behind each lateral incisor. They are larger
and stronger than the incisors, especially the root, which sinks deeply into the
jaw, and causes a well-marked prominence upon its surface.
The crown is large and conical, very convex in front, a little hollowed and .
nneven posteriorly, and tapering to a blunted point, or cusp, which rises above
the level of the other teeth.
The root is single, but longer and thicker than that of the incisors, conical in
form, compressed laterally, and marked by a slight groove on each side.
The upper canine teeth (vulgarly called eye-teeth) are larger and longer than
the two lower, and situated a little behind them.
The loiver canine teeth are placed in front of the npper, so that their summits
correspond to the interval between the upper canine tooth and the neighboring-
incisors on each side.
The Bicuspid Teeth (small^ or false molars) are eight in number, four in each
jaw, two being placed immediately behind each of the canine teeth. They are
smaller and shorter than the canine.
The crown is compressed from without inwards, and surmounted by two pyra-
midal eminences, or cusps, separated by a groove, hence their name hicuspidate.
The outer of these cusps is larger and more prominent than the inner.
The nech is oval.
The rooi is generally single, compressed, and presents a deep groove on each
side, which indicates a tendency in the root to become double. The apex is
generally bilid.
The upper bicuspids are larger, and present a greater tendency to the division
of their roots than the lower ; this is especially marked in the second upper
bicusy)id.
Tiic Molar Teeth {multicuspidati^ true, or large molars) are the largest of the
permanent set, and are adapted, from the great breadth of their crowns, for
grinding and pounding the food. They are twelve in number, six in each jaw,
throe being placed behind each of the posterior bicuspids.
The crown is nearly cubical in form, rounded on each of its lateral surfaces,
flattened in front and behind; the upper surface being surmounted by four or
five tubercles, or cusps (four in the upper, five in the lower molars), separated
from each other by a crucial depression, hence their name, multicuspidati.
The nech is distinct, large, and rounded.
The root is subdivided into from two to five fangs, each of whicli presents an
aperture at its summit.
Tiie first molar tooth is the largest and broadest of all : its crown has usually
five cusps, three outer and two inner. In the u])per jaw, the root consists of
three fangs, widely separated from one another, two being external, the other
internal. The latter is the largest and the longest, slightly grooved, and some-
times l)i(id. In the lower jaw, the root consists of two fangs, one being placed
TEMPORARY TEETH,
749
in front, the other behind : they are both compressed from before backwards,
and grooved on their contiguous faces, indicating a tendency to division.
The second molar is a little smaller than the first.
The crown has four cusps in the upper, and five in the lower jaw.
The root has three fangs in the upper jaw, and two in the lower, the characters
of which are similar to the preceding tooth.
The third molar tooth is called, the wisdom tooth {dens sapientise) from its late
appearance through the gum. It is smaller than the others, and its axis is
directed inwards.
The crown is small and rounded, and furnislied with three tubercles.
The root is generally single, short, conical, slightly curved, and grooved so
as to present traces of a subdivision into three fangs in the upper, and two in
the lower jaw.
Temporary Teeth.
The Temporary or Milk Teeth are smaller, but resemble in form those of
the permanent set. The hinder of the two temporary molars is the largest of
Fig. 421.— The Temporary, or Milk Teetli. External View.
J a 10
ZjOwp't Jaw
all the milk teeth, and is succeeded by the second permanent bicuspid. The
first upper molar has only three cusps, two external, one internal: the second
upper molar has four cusps. The first lower molar has four cusps; the second
lower molar has five. The fangs of the temporary molar teeth are smaller, and
more diverging than those of the permanent set ; but, in other respects, bear a
strong resemblance to them.
Structure. On making a vertical section of a tooth (Fig. 422), a hollow cavity
will be found in the interior. This cavity is situated at the base of the crown,
and is continuous with a canal which traverses the centre of each fang, and opens
by a minute orifice at its extremity. The shape of the cavity corresponds some-
what with that of the tooth ; it forms what is called the pulp cavity^ and contains
a soft, highly vascular, and sensitive substance, the dental pulp. The pulp
is richly supplied with vessels and nerves, which enter the cavity through the
small aperture at the point of each fang.
750
ORGANS OF DIGESTION.
If — Neck
aSl'I— J'""*!
parietes. They
Fig. 423.— Vertical Sec-
tion of a Bicuspid Tooth.
(Magnified.
Fig. 422.— Vertical The solid portion of the tooth consists of three distinct
Section of a Molar structures, viz., ivory (tooth -bone, or dentine), which forms
the larger portion of th-e tooth; enamel, which covers the
exposed part, or crown ; and the cortical substance, or cement
{crusta jjetrosa)^ which is disposed as a thin layer on the surface
of the fang.
The IvoKY, or dentine (Fig. 423), forms the principal mass
of a tooth ; in its central part is the cavity inclosing the pulp.
It is a modification of the osseous tissue, from which it differs,
however, in structure and chemical composition. On ex-
amination with the microscope, it is seen to consist of a num-
ber of minute wavy and branching tubes, having distinct
are called the dental tuhuli^ and are embedded in a dense
homogeneous substance, the intertuhular tissue.
The dental tubuli are placed parallel with one another, and open at their inner
ends into the pulp cavity. They pursue a wavy and undulating course towards
the periphery. The direction of these tubes varies;
they are vertical in the upper portion of the crown,
oblique in the neck and upper part of the root, and
towards the lower part of the root they are inclined
downwards. The tubuli, at their commencement, are
about 43 0 0 of an inch in diameter; in their course they
divide and subdivide dichotomously, so as to give to
the cut surface of the dentine a striated appearance.
From the sides of the tubes, especially in the fang,
ramifications of extreme minuteness are given off, which
join together in loops in the intertubular substance, or
terminate in small dilatations, from which branches are
given off. Near the periphery of the dentine, the finer
ramifications of the tubuli terminate in a somewhat
similar manner. In the fang these ramifications occa-
sionally |)ass into the crusta petrosa. The dental tubuli
have comparatively thick walls, and contain slender
cylindrical prolongations of the pulp-tissue, first described
by Mr. Tomes, and named Tomes's fibres, or dentinal
',' fibres. These dentinal fibres are analogous to the soft
/ contents of the canaliculi of bone. They commence in
/ cells, the odontoblasts of Waldeyer, which will be more
^'^^-^ particularly described in the next section. Between
Tomes's fibres and the ivory of the canals, there is an
elastic homogeneous membrane which resists the action of acids, the dentinal
shea tic of Neumann.
The intertuhular substance is translucent, finely granular, and contains the
chief part of the earthy matter of the dentine. After the earthy matter has
been removed, by steeping a tooth in weak acid, the animal basis remaining is
described by Ilcnle as consisting of bundles of pale, granular, flattened fibres,
running parallel with the tubes; but by Mr. Nasmyth as consisting of a mass
of briclv-shapcd cells surrounding the tubules. By C/ermak and Mr. Salter it
is supposed to consist of lamime which run parallel with the pulp cJivity, across
the direction of the tubes. A section of dentine displays just below the cement
a series of irregular cavities, "the interglobular spaces" of Czermak, or granular
layer of Purkinjc, the spaces of which are filled up by a transparent soft material.
Tlic section of the dentine is marked by a^ series of somewhat parallel lines — the
"incremental lines" of Salter — produced by the curving of tlic dentinal tubuli
during the growth of the toolh.
Chemical Coinposilion. According to Ik'.rzelius ami IVibi-n, (U'litine consists of
28 parts of animal, and 72 of earthy matter. The animal matter is resolvable
DEVELOPMENT OF THE TEETH. 751
by boiling into gelatin. The earthy matter consists of phosphate of lime,
carbonate of lime, a trace of fluoride of calcium, phosphate of magnesia, and
other salts.
The Enamel is the hardest and most compact part of a tooth, and forms a
thin crust over the exposed part of the crown, as far as the commencement of
the fang. It is thickest on the grinding surface of the crown, until worn away
by attrition, and becomes thinner towards the neck. It consists of a congeries
of minnte hexagonal rods. They lie parallel with one another, resting by one
extremity upon the dentine, which presents a number of minute depressions for
their reception; and forming the free surface of the crown by the other ex-
tremity. These fibres are directed vertically on the summit of the crown,
horizontally at the sides; they are about the g^Vii of an inch in diameter, and
pursue a more or less wavy course. The enamel is marked by a series of un-
dulating lines which cross each other or "decussate;" these lines are doubtless'
formed by the variation in the course of the enamel-rods. Another series of
lines, colored brown probably from the presence of pigment, and denominated
the parallel strise of Eetzius, are seen on a section of the enamel. Their exact
significance is uncertain.
Numerous minute interstices intervene between the enamel fibres near their
dentinal surface, a provision calculated to allow of the permeation of fluids from
the dentinal tubuli into the substance of the enamel. The enamel-rods consist
of solid hexagonal or four- sided prisms connected , by their surfaces and ends,
and filled with calcareous matter. If the latter is removed, by weak acid, from
newly-formed or growing enamel, it will be found to present a network of deli-
cate prismatic cells of animal matter. It is a disputed point whether the denti-
nal fibres penetrate a certain distance between the rods of the enamel or no.
No nutritive canals exist in the enamel.
Chemical Composition. According to Bibra, enamel consists of 96.5 per cent,
of earthy matter, and 3.5 per cent, of animal matter. The earthy matter con-
sists of phosphate of lime, with traces of fluoride of calcium, carbonate of lime,
phosphate of magnesia, and other salts.
The Cortical Substance, or cement (crusta petrosa), is disposed as a thin
layer on the roots of the teeth, from the termination of the enamel, as far as the
apex of the fang, where it is usually very thick. In structure and chemical
composition, it resembles bone. It contains, sparingly, the lacunee and canaliculi
which characterize true bone; the lacunae placed near the surface, have the
canaliculi radiating from the side of the lacunae towards the periodontal mem-
brane ; and those more deeply placed, join with the adjacent dental tubuli. In
the thicker portions of the crusta petrosa, the lamellae and Haversian canals
peculiar to bone are also found. As age advances, the cement increases in
thickness, and gives rise to those bony growths, or exostoses, so common in the
teeth of the aged; the pulp cavity becomes also partially filled up by a hard
substance, intermediate in structure between dentine and bone (osteo-dentine,
Owen ; secondary dentine^ Tomes). It appears to be formed by a slow conver-
sion of the dental pulp, which shrinks, or even disappears.
Development of the Teeth. (Figs. 424 to 429.)
In describing the development of the teeth it has seemed better to give the
more modern account first, and then that of Goodsir, which was till recentl}^
universally accepted.
According to the description now generally adopted (that of Waldeyer), the
development of the teeth in the foetus begins at a very early period, about the
seventh week. On the surface of the jaw there is found a depression or groove
("the dental groove"), the surface of which is formed of a collection of epithelial
cells, the tissue below of gelatinous and cellular substance, which is taken to
represent the corium and cellular tissue of the mucous membrane, and deeper
752
ORGANS OF DIGESTION.
than which, is the ossifying substance of the jaw (Fig. 424). The essential
structures of the teeth are derived from these two elements, the enamel from
epithelium which covers the surface of the dental groove, the dentine and crusta
petrosa from the deeper structures.
Fio-. 424.
Vertical section of the iuferior maxilla of an early human foetus. (Magnified 25 diams.) 1. Dental groove. 2.
Remains of the enamel-germ. 3. Enamel organ, presenting externally epithelium, as also where it forms the enamel-
germ of the papillae of the dental sacculus. 4. Secondary enamel germ ; rudiment of the permanent tooth. 5. Deutal
germ. 6. Lower jaw. 7. Meckel's cartilage.
First as to the enamel. The epithelium becomes heaped up over the margins '
of the dental groove, and then passes down into it, and as the sides of the groove
rise up, the epithelial mass (or " enamel organ") seems to pass deeper and deeper
into the substance of the jaw, meeting with tlie papilla, presently to be described,
from which the dentine or bulk of the tooth is developed, and assuming the form
of a flask or cap united to the superficial layer of epithelium by a neck, bridge,
or string of epithelium. This string is the gubernacuhim or future enamel
organ of the permanent tooth. As the dental papilla grows up from the bottom
of the groove, the enamel organ folds itself over it in the form of a cap, or cap-
sule, presenting an outer and inner surface, still epithelial (Fig. 425), and an
intermediate portion undergoing development into the proper enamel tissue.
The epithelial covering on the outer surface of the enamel long remains dis-
tinctly perceptible. After the tooth has emerged from the gum, this layer may
1)C separated from the calcified mass below by the action of strong acids, in the
i'orm of a membrane (cuticula dentis, Nasmyth's membrane) marked by the
licxagonal impressions of the enamel prisms, and when stained by nitrate of
silver showing the characteristic appearance of epithelium. This membrane
soon wears away from the surface of the tooth.
The bulk of the enamel is formed by the calcification of the epillielial cells, '
wliich are changed into hexagonal prisms, the communication of which with
each other forms the hexagonal rods of the mature enamel ; but the exact rela-
tion of the embryonic cells to the future rods, and llio precise reason of the
appearance of the transverse strice on the latter, have not yet been satisfaclorily
demon. St rated. The calcificati(m of the successive layers of epithelium is pre-
ceded by the production of a gelatinous mass (the "enamel jelly") between the
investing epithelium and the calcifying ti.'^sue.
As the epillif>,liuin is undergoing this remarkable development a projection of
the mucous tissue (blastema, or corium) of tlie infantile jaw springs up to meet
it out of the bottom of tlie dciilal groove. Tliis projection was described by
DEVELOPMENT OF THE TEETH.
753
Goodsir as a row of separate papilla. It is now described, after Dursy and
Waldejer, as a ridge, the intervening parts of whicli are atrophied, so as to leave
papillae, which become coated all over by the enamel organ, and thus the saccu-
lar stage of the teeth is produced, the papillae which are to form the bulk of the
teeth being coated with a vascular connective tissue, isolated by the enamel
organ, and separated from each other by the growing tissue of the foetal jaw.
The next step is the formation of the odontoblasts, which have a relation to
the development of the teeth similar to that of the osteoblasts to the formation
of bone. These are large nucleated cells of elongated form and provided with
numerous processes develo23ed from the cells of the dental papilla, which at that
early stage consist of a fine fibrous tissue containing a number of cells, likened
Fig. 425.
Fisr. 426.
Canine tootli of man, presenting a portion of the
transverse section of the root. 1. Cement with
large lacunae and parallel strias. 2. Interglobular
substance. 3. Dentinal tubules. (Magnified 300
diams.)
Dental sac of a human embryo at au advanced stage of develop-
ment, partly diaj'ramatic. n. Wall of the sac, formed of connec-
tive tissue with its outer stratum «! and its inner a'-, h. Euamel
organ, with its papillary and parietal layer of cells, e, d. The
enamel-membrane and enamel prisms, e, Dentine cells. /.
Dental germ and capillaries, g, i. Transition of the wall of the
follicle into the tissue of the denial ge.m.
by Waldeyer to the structure of old atrophied
umbilical cords, the elastic tissue only being
absent. The odontoblasts send out pro-
cesses, which, as they grow, become calcified
externally, the calcified portion forming the
ivory, the uncalcified part the dentinal fibres
(Tomes's fibres), and the lateral processes
the branches of anastomosis whereby the dentinal canals anastomose. The re-
mains of the odontoblasts themselves form what is known as the "membrana
eboris" of Kolliker, a cellular layer which forms the investment of the pulp
lying between its nerves and vessels and the dentine.
The cement is ordinary bone, containing canaliculi and lacunae, and developed
from the deeper tissues of the foetal jaw, exactly as bone is produced in other
parts of the body by periosteal ossification. Haversian canals are found accord-
ing to Salter, where the cement is thick.
The germs of the milk teeth make their appearance in the following order :
at the seventh week, the germ of the first molar of the upper jaw appears ; at
the eighth week, that for the canine tooth is developed: the two incisor papilla
appear about the ninth week (the central preceding the lateral); lastly, the
second molar papilla is seen at the tenth week, behind the anterior molar. The
48
754
ORGANS OF DIGESTION.
Fiff. 427. — Development of Teeth
(after Goodsir's description).
CJifrcuZw
423.
FIG. 429.
teeth of tlie lower jaw appear rather later, the first molar papilla being only-
just visible at the seventh week; and the tenth papilla not being developed
before the eleventh week. This completes the first or papillary stage of their
develoj^ment.
According to Goodsir's description the dental groove now becomes contracted,
its margins thickened and prominent, and the groove is converted into follicles
for the reception of the papillee, by the growth
of membranous septa, which pass across the
groove between its borders (Fig. 427). The folli-
cles by this means become the alveoli, lined by
periosteum, from the bottom of which the pro-
cess of the mucous membrane of the gnm rises,
which is the germ of the future tooth. The
follicle for the first molar is complete about the
tenth week; the canine follows next, succeeded
by the follicles for the incisors, which are com-
pleted about the eleventh or twelfth week ; and,
lastly, the follicle of the posterior molar is com-
j^leted about the fourteenth week. These changes
constitute the second or follicular stage.
About the thirteenth week, the papillse begin
to grow rapidly, project from the follicles, and
assume a form corresponding with that of the
future teeth: the follicles soon become deeper,
and from their margins small membranous pro-
cesses, or opercula, are developed, which, meeting,
unite and form a lid to the now closed cavity
(Fig. 428). These processes correspond in shape
to the form of the crown of the tooth, and in
number to the tubercles on its surface. The
follicles of the incisor teeth have two opercula,
the canine three, and the molars four or five each.
The follicles are thus converted into dental sacs,
and the contained papillae become pulps. The
lips of the dental groove gradually advance over
the follicles from behind forwards, and, uniting,
gradually obliterate it. This completes the third
or saccular stage, which takes place about the
end of the fifteenth week.
The deep portion of the primitive dental groove
is now closed in ; but the more superficial portion,
near the surface of the gum, still remains open ;
it is called, by Mr. Goodsir, the secondary dental
groove; from it are developed the ten anterior
permanent teeth. About the fourteenth week,
certain lunatcd depressions are formed, one behind
each of the sacs of the rudimentary milk teeth.
They are ten in number in each jaw, and arc
formed successively from before backwards ; they
are the rudimentary follicles of the four permanent incisors, the two canine, and
the four bicuspids. As the secondary dental groove closes in, the follicles be-
come closed cavities of reserve (Fig. 428). The cavities soon elongate and
recede from the surracc into the substance of the gum, behind the sacs of the
deciduous tcotli, and a jjapilla projects from the bottom of each, which is the
germ of the permanent tooth ; at the same time, one or more opercula are de-
veloped from the sides of the cavity; and these, uniting, divide it into two
portions; the lower portion containing the papilla of the permanent tooth, the
FIG. 430.
Sru/ition of Milk'totrbh-
Pjf^HMTivnt lot^uK
DEVELOPMENT OF THE TEETH. 755
upper narrower portion becoming gradually contracted in tlie same way that
the primitive dental groove was obliterated over the sacs of the deciduous teeth
(Fig. 429).
The six posterior permanent teeth in each jaw, three on each side, arise from
successive extensions backwards of the back part of the primitive dental groove.
During the fourth month, that portion of the dental groove which lies behind
the last temporary molar follicle remains open, and from it is developed the
papilla, the rudiment of the first permanent molar. The follicle in which it is
contained becomes closed by its operculum, and the upper part of the newly-
formed sac elongates backwards to form a cavity of reserve, in which the papilla
of the second permanent molar appears at the seventh month after birth. After
a considerable interval, during which the sacs of the first and second permanent
molars have considerably increased in size, the remainder of the cavity of reserve
presents for the last time a series of changes similar to the preceding, and gives
rise to the sac and papilla of the wisdom-teeth, which appear at the sixth year.
The chief difference, therefore, between Goodsir's description and those of
later anatomists is that he did not recognize the epithelial origin of the enamel,
describing merely the "opercula," which in the modern description would be
recognized only as part of the ordinary connective tissue in which the papilla is
imbedded (Fig. 425, a). The origin of the dentinal fibres from the odontoblasts
is another matter of primary importance which was not recognized in the older
descriptions.
Eruption. When the calcification of the different tissues of the tootli is sufii-
ciently advanced to enable it to bear the pressure to which it will be afterwards
subjected, its eruption takes place, the tooth making its way through the gum.
The gum is absorbed by the pressure of the crown of the tooth against it, which
is itself pressed up by the increasing size of the fang (Fig. 430). At the same
time, the septa between the dental sacs, at first fibrous in structure, ossify, and
constitute the alveoli ; these firmly embrace the necks of the teeth, and afford
them a solid basis of support.
The eruption of the temporary teeth commences at the seventh month, and is
complete about the end of the second year, those of the lower jaw preceding the
upper.
The periods for the eruption of the temporary set are .
7th month, central incisors. 14th to 20th month, canine.
7th to 10th month, lateral incisors. 18th to 36th month, posterior molars.
12th to 14th month, anterior molars.
Calcification of the permanent teeth commences a little before birth, and
proceeds in the following order in the upper jaw, in the lower jaw a little
earlier: First molar, five or sixth months; the central incisor, a little Jater;
lateral incisors and canine, about the eighth or ninth month; the bicuspids at the
second year ; second molar, five or six years ; wisdom tooth, about twelve years.
Previous to the permanent teeth penetrating the gum, the bony partitions
which separate their sacs from the deciduous teeth are absorbed, the fangs of
the temporary teeth disappear, and the permanent teeth become placed under
the loose crowns of the deciduous teeth; the latter finally become detached, and
the permanent teeth take their place in the mouth.
The eruption of the permanent teeth takes place at the following periods, the
teeth of the lower jaw preceding those of the upper by a short interval:
6J years, first molars. 10th year, second bicuspid.
7th year, two middle incisors. 11th to 12th year, canine.
8th year, two lateral incisors. 12th to 13th year, second molars.
9th year, first bicuspid. 17th to 21st year, wisdom-teeth.
756 ORGANS OF DIGESTION.
The Palate.
The Palate forms tlie roof of tlie mouth; it consists of two portions, the hard
palate in front, the soft palate behind.
The hard •palate is bounded in front and at the sides by the alveolar arches
and gums; behind, it is continuous with the soft palate. It is covered by a
dense structure, formed by the periosteum and mucous membrane of the mouth,
which are intimately adherent together. Along the middle line is a linear ridge
or raphe, which terminates anteriorly in a small papilla, corresponding with the
inferior opening of the anterior palatine fossa. This papilla receives filaments
from the naso-palatine and anterior palatine nerves. On either side and in front
of the raphe, the mucous membrane is thick, pale in color, and corrugated ;
behind, it is thin, smooth, and of a deeper color; it is covered with squamous
epithelium, and furnished with numerous glands (palatal glands), which lie
between the mucous membrane and the surface of the bone.
The soft palate {velum pendulum palati) is a movable fold, suspended from
the posterior border of the hard palate, and forming an incomplete septum
between the mouth and pharynx. It consists of a fold of mucous membrane,
inclosing muscular fibres, an aponeurosis, vessels, nerves, and mucous glands.
When occupying its usual position [i. e., relaxed and pendent), its anterior
surface is concave, continuous with the roof of the mouth, and marked by a
median ridge or raphe, which indicates its original separation into two lateral
halves. Its posterior surface is convex, and continuous with the mucous mem-
brane covering the floor of the posterior nares. Its upper border is attached
to the posterior margin of the hard palate, and its sides are blended with the
pharynx. Its lower border is free.
Hanging from the middle of its lower border is a small conical-shaped pendu-
lous process, the uvula; and arching outwards and downwards from the base
of the uvula on each side, are two curved folds of mucous membrane, containing'
muscular fibres, called the arches or pillars of the soft palate.
The anterior pillar runs downwards, outwards, and forwards to the side of the
base of the tongue, and is formed by the projection of the Palato-glossus muscle,
covered by mucous membrane.
The posterior pillars are nearer to each other and larger than the anterior ;
they run downwards, outwards, and backwards to the sides of the pharynx,
and are formed by the projection of the Palato-pharyngei muscles, covered by
mucoas membrane. The anterior and posterior pillars are separated below by
a triangular interval, in which the tonsil is lodged.
The space left between the arches of the palate on the two sides is called the
isthmus of the fauces. It is bounded above by the free margin of the palate;
below by the tongue; and on each side by the pillars of the soft palate and
tonsils.
The mucous m^nnhrane of the soft palate is thin, and covered with squamous
epithelium on both surfaces, excepting near the orifice of the Eustachian tube,
wJicre it is colunmar and ciliated. The palatine glands form a continuous laj^er
on its posterior surface and round the uvula.
The aponeurosis of the soft palate is a thin but firm fibrous la3xr, attached
above to the hard palate, and becoming thinner towards the free margin of the
velum. It is blended with the aponeurotic tendon of the Tensor palati muscle.
The muscles of the soft palate are five on each side: the Levator ])alati, Tensor
palati, Palato-glossus, Palato-pharyngeus, and Azygos uvula) (see p. 869).
Tlie tonsils {arny(jdahx') are two glandular organs, siluated one on each side
of the fauces, between tlie anterior and posterior pillars of the soft palate. They
are of a rounded form, and vary considerably in si/e in difiercnt individuals.
Externally, the tonsil is in relation with the inner surface of the Superior
constrictor (beyond wliich arc the internal carotid and ascending pharyngeal
arteries), .ind corresponds to the angle of the lower jaw. Its inner surface
THE SALIVARY GLANDS.
757
presents from twelve to fifteen orifices, leading into small recesses, from which.
numerous follicles branch, out into the substance of the gland. These follicles
are lined bj a continuation of the mucous membrane of the pharynx, covered
with epithelium, their walls being formed by a layer of closed capsules imbedded
in the submucous tissue. These capsules are analogous to those of Peyer's
glands; they contain a thick grayish secretion.
The arteries supplying the tonsil are the dorsalis linguae from the lingual, the
ascending palatine and tonsillar from the facial, the ascending pharyngeal from
the external carotid, and the descending palatine branch of the internal max-
illary.
The veins terminate in the tonsillar plexus, on the outer side of the tonsil.
The nerves are derived from the fifth, and from the glosso-pharyngeal.
The Salivaey Glands. (Fig. 431.)
The principal Salivary Glands communicating with the mouth, and pouring
their secretion into its cavity, are the parotid, submaxillary, and sublingual.
The Parotid Gland, so called from being placed near the ear (napa, near;
ovs, uToi, the ear), is the largest of the three salivary glands, varying in weight
from half an ounce to an ounce. It lies upon the side of the face, immediately
below and in front of the external ear. It is limited above by the zygoma ;
Fig. 431.— The Salivary Glands.
below, by the angle of the jaw, and by a horizontal line drawn between it and
the mastoid process : anteriorly, it extends to a variable extent over the Masse-
ter muscle ; posteriorly, it is bounded by the external meatus, the mastoid pro-
cess, and the Sterno-mastoid and Digastric muscle's, slightly overlapping the
former.
Its anterior surface is grooved to embrace the posterior margin of the ramus
of the lower jaw, and advances forwards beneath the ramus, between the two
758 ORGANS OF DIGESTION.
pterygoid muscles. Its outer surface, sliglitly lobulated, is covered by the in-
tegument and fascia, and lias one or two lymphatic glands resting on it. Its
inner surface extends deeply into the neck, by means of two large processes, one
of which dips behind the styloid process, and projects beneath tiie mastoid pro-
cess and the Sterno-mastoid muscle; the other is situated in front of the styloid
process, and passes into the back part of the glenoid fossa, behind the articula-
tion of the lower jaw. Embedded in its substance is the external carotid artery,
which ascends behind the ramus of the jaw ; the posterior auricular artery
emerges from the gland behind ; the temporal artery above ; the transverse
facial in front ; and the internal maxillary winds through it inwards, behind the
neck of the jaw. Superficial to the external carotid is the trunk formed by the
union of the temporal and internal maxillary veins ; a branch, connecting this
trunk with the internal jugular, also traverses the gland. It is also traversed,
from before backwards, by the facial nerve and its branches, which emerge at
its anterior border ; the great auricular nerve pierces the gland to join the facial,
and the temporal branch of the inferior maxillary nerve lies above the upper
part of the gland. The internal carotid artery and internal jugular vein lie
close to its deep surface.
The duct of the parotid gland (Steno's) is about two inches and a half in
length. It opens upon the inner surface of the cheek by a small orifice, opposite
the second molar tooth of the upper jaw ; and from this orifice it may be traced
obliquely for a short distance beneath the mucous membrane, and thence
through the substance of the Buccinator muscle, and across the Masseter to the
anterior border of the gland, in the substance of which it commences by nume-
rous branches. The direction of the duct corresponds to a line drawn across
the face about a finger's breadth below the zygoma, from the lower part of the
concha, to midway between the free margin of the upper lip and the ala of the
nose. While crossing the Masseter, it receives the duct of a small detached
portion of the gland, socia parotidis^ which occasionally exists as a separate lobej
just beneath the zygomatic arch. The parotid duct is dense, of considerable
thickness, and its canal about the size of a crow-quill ; it consists of an external
or fibrous coat, of considerable density, containing contractile fibres, and of an
internal or mucous coat lined with columnar epithelium.
Vessels and Nerves. The arteries supplying the parotid gland are derived
from the external carotid, and from the branches given off by that vessel in or
near its substance. The veins follow a similar course. The lympliatics termi-
nate in the superficial and deep cervical glands, passing in their course through
two or three lymphatic glands, placed on the surface and in the substance of the
parotid. The nerves are derived from the carotid plexus of the sympathetic,
the facial, and the superficial temporal branches of the auriculo-temporal, and
great auricular nerves.
The Submaxillary Gland is situated below the jaw, in the anterior part of
the submaxillary triangle of the neck. It is irregular in form, and weighs
about two drachms. It is covered by the integument, Platysma, deep cervical
fascia, and the body of the lower jaw, corresponding to a depression on the inner
surface of that bone; and lies upon the Mylo-hyoid, Ilyo-glossus, and Stylo-
glossus muscles, a y)ortion of the gland passing beneath the posterior border of
the Mylo-hyoid. In front of it is the anterior belly of the Digastric; behind,
it is separated from the parotid gland by the stylo-maxillary ligament, and
from the sublingual gland in front by the Mylo-hyoid muscle. The facial
artery lies imbedded in a groove in its ]iosterior and uj)per border.
The dnc.t of the submaxillary gland (Wharton's) is ab(mt two inches in length,
and its walls arc much thinner than those of the parotid duct. It oj)ens by a
narrow orifice on 1lie summit of a small papilla, at the side of the frtcnum
linguae. Traced fVoin ihencc it is found to pass between the sublingual gland
and the Gcnio-hyo-glossns muscle, then backwards and outwards between the
Mylo-hyoid, and the Ilyo-glossus and Genio-hyo-glossus muscles, and above the
THE PHARYNX. 759
gustatory nerve, to the deep portion of tlie gland, where it commences by nume-
rous branches.
Vessels and Nerves. The arteries supplying the submaxillary gland are
branches of the facial and lingual. Its veins follow the course of the arteries.
The nerves are derived from the submaxillary ganglion, from the mylo-hyoid
branch of the inferior dental, and from the sympathetic.
The Sublingual Gland is the smallest of the salivary glands. It is situated
beneath the mucous membrane of the floor of the mouth, at the side of the
fraenum linguge, in contact with the inner surface of the lower jaw, close to the
symphysis. It is narrow, flattened, in shape somewhat like an almond, and
weighs about a drachm. It is in relation, ahove^ with the mucous membrane;
heloiv, with the Mylo-hyoid muscle; infront^ with the depression on the side of
the symphysis of the lower jaw, and with its fellow of the opposite side; behind^
with the deep part of the submaxillary gland; and internally^ with the Genio-
hyo-glossus, from which it is separated by the lingual nerve and Wharton's
duct. Its excretory ducts (ductus Riviniani)^ from eight to twenty in number,
open separately into the mouth, on the elevated crest of mucous membrane,
caused by the projection of the gland, on either side of the frasnum linguge.
One or more join to form a tube which opens into the Whartonian duct; this
is called the duct of Bartlioline.
Vessels and Nerves. The sublingual gland is supplied with blood from the
sublingual and submental arteries. Its nerves are derived from the gustatory.
Structure. The salivary are conglomerate glands, consisting of numerous
lobes, which are made up of smaller lobules, connected together by deiise areolar
tissue, vessels, and ducts. Each lobule consists of numerous closed vesicles, which
open into a common duct; the wall of each vesicle is formed of a delicate base-
ment membrane, lined by epithelium, and covered on its outer surface with a
dense capillary network. In the submaxillary and sublingual glands, the lobes
are larger and more loosely united than in the parotid.
The Pharynx,
The Pharynx is that part of the alimentary canal which is placed behind the
nose, mouth, and larynx. It is a musculo-membranous sac, somewhat conical in
form, with the base upwards, and the apex downwards, extending from the under
surface of the skull to the cricoid cartilage in front, and the fifth cervical verte-
bra behind.
The pharynx is about four inches and a half in length, and broader in the
transverse than in the antero- posterior diameter. Its greatest breadth is oppo-
site the cornua of the hyoid bone ; its narrowest point at its termination in the
oesophagus. It is limited, above, by the basilar process of the occipital bone;
below, it is continuous with the oesophagus; posteriorly, it is connected by loose
areolar tissue with the cervical portion of the vertebral column, and the Longi-
colli and Eecti capitis antici muscles ; anteriorly, it is incomplete, and is attached
in succession to the internal pterygoid plate, the ptery go-maxillary ligament, the
lower jaw, the tongue, hyoid bone, and larynx ; lateraUy, it is connected to the
styloid processes and their muscles, and is in contact with the common and
internal carotid arteries, the internal jugular veins, and the eighth, ninth, and
sympathetic nerves, and above, with a small part of the Internal pterygoid
muscles.
It has seven openings communicating with it ; the two posterior nares, the
two Eustachian tubes, the mouth, larynx, and oesophagus.
The posterior nares are the two large apertures situated at the upper part of
the anterior wall of the phar3mx.
The tivo Eustachian tidies open one at each side of the upper part of the pha-
rynx, at the back part of the inferior meatus. Below the nasal fossae are the
760 ORGANS OF DIGESTION.
posterior surface of the soft palate and uvula, the large aperture of the mouth,
the base of the tongue, the epiglottis, and the cordiform opening of the larynx.
The cesoiphageal opening is the lower contracted portion of the pharynx.
Structure. The pharynx is composed of three coats: mucous, fibrous, and
muscular.
The fibrous coat is situated between the mucous and muscular layers, and is
called the pharyngeal aponeurosis. It is thick above, where the muscular fibres
are wanting, and is firmly connected to the basilar process of the occipital and
petrous portion of the temporal bones. As it descends, it diminishes in thick-
ness and is gradually lost.
The mucous coat is continuous with that lining the Eustachian tubes, the nares,
the mouth, and the larynx. It is covered by columnar ciliated epithelium, as
low down as on a level with the floor of the nares; below that jjoint, the epi-
thelium is of the squamous variety.
The muscular coat has been already described (p. 366).
The pJiaryngeal glands are of two kinds: the simple, or compound follicular,
which are found in considerable numbers beneath the mucous membrane, through-
out the entire pharynx; and the racemose, which are especially numerous at the
upper part of the pharynx, and form a thick layer, across the back part of the
fauces, between the two Eustachian tubes.
The (Esophagus.
The (Esophagus is a membranous canal, about nine inches in length, extending
from the pharynx to the stomach. It commences at the lower border of the
cricoid cartilage, opposite the fifth cervical vertebra, descends along the front
of the spine, through the posterior mediastinum, passes through the diaphragm,
and, entering the abdomen, terminates at the cardiac orifice of the stomach,
opposite the ninth dorsal vertebra. The general direction of the oesophagus is
vertical ; but it presents two or three slight curvatures in its course. At its
commencement, it is placed in the median line ; but it inclines to the left side as
far as the root of the neck, gradually passes to the middle line again, and finally
again deviates to the left, as it passes forwards to the oesophageal opening of the
Diaphragm. The oesophagus also presents an antero-posterior flexure, corre-
sponding to the curvature of the cervical and thoracic portions of the spine. It
is the narrowest part of the alimentary canal, being most contracted at its com-
mencement, and at the point where it passes through the Diaphragm.
delations. In the neck, the oesophagus is in relation, in front, with the trachea ;
and, at the lower part of the neck, where it projects to the left side, with the
thyroid gland and thoracic duct; behind, it rests upon the vertebral column
and Longus colli muscle; on each side it is in relation with the common carotid
artery (especially the left, as it inclines to that side), and part of the lateral lobes
of the thyroid gland ; the recurrent laryngeal nerves ascend between it and the
trachea.
In the thorax, it is at first situated a little to the left of the median line : it
then passes across the left side of the transverse part of the aortic arch, and
descends in the posterior mediastinum, along the right side of the aorta, nearly
to tlic Diaphragm, where it passes in front and a little to the left of the artery,
previous to entering the abdomen. It is in relation, in front, with the trachea,
the arch of the aorta, left carotid, and left subclavian arteries, the left bronchus,
and the posterior surface of the pericardium ;7;(-Am<:?, it rests upon the verte-
bral column, the Longus colli, and the intercostal vessels; and below, near the
Diaphragm, upon the front of the aorta; laterally it is covered by the pleura?:
the vena azygos major lies on the riglit, and the descending aorta on the left
side. The pncumogastric lu-rves descend in close contact with il, the right ncrvo
passing down behind, and the left nerve in front of it.
THE ABDOMEN. 761
Surgical Anatomy. The relations of the oesophagus are of considerable practical interest to
the surgeon, as he is frequently required, in cases of stiicture of this tube, to dilate the canal by
a bougie, wlien it becomes of importance that the direction of the oesophagus, and its relations
to surrounding parts, should be remembered. In cases of malignant disease of the oesophagus,
where its tissues have become softened from infiltration of the morbid deposit, the greatest care
is requisite in directing the bougie through the strictured part, as a false passage may easily be
made, and the instrument may pass into the mediastinum, or into one or the other pleural cavity,
or even into the pericardium.
The student should also remember that contraction of the oesophagus, and consequent symp-
toms of stricture, are occasionally produced by an aneurism of some part of the aorta pressing
upon this tube. In such a case, the passage of a bougie could only hasten the fatal issue.
It occasionally happens that a foreign body becomes impacted in the oesophagus, which can
neither be brought upwards nor moved downwards. When all ordinary means for its removal
have failed, excision is the only resource. This, of course, can only be performed when it is not
very low down. If the foreign body is allowed to remain, extensive inflammation and ulceration
of the oesophagus may ensue. In one case with which I am acquainted, the foreign body ulti-
mately penetrated the intervertebral substance, and destroyed life by inflammation of the mem-
branes and substance of the cord.
The operation of oesophagotomy is thus performed. The patient being placed upon his back,
with the head and shoulders slightly elevated, an incision, about four inches in length, should be
made on the left side of the trachea, from the thyroid cartilage downwards, dividing the skin and
Platysma. The edges of the wound being separated, the Omo-hyoid muscle, and the fibres of the
Sterno-hyoid and Sterno-thyroid muscles, must be drawn inwards ; the sheath of the carotid ves-
sels being exposed, should be drawn outwards, and retained in that position by retractors; the
oesophagus will then be exposed, and should be divided over the foreign body, which should then
be removed. Great care is necessary to avoid wounding the thyroid vessels, the thyroid gland,
and the laryngeal nerves.
Structure. The oesopliagus has three coats : an external, or muscular ; a middle,
or cellular; and an internal, or mucous coat.
The muscular coat is composed of two planes of fibres of considerable thickness,
an external longitudinal, and an internal circular.
The longitudinal fibres are arranged at the commencement of the tube, in three
fasciculi : one in front, which is attached to the vertical ridge on the posterior
surface of the cricoid cartilage ; and one at each side, which are continuous with
the fibres of the Inferior constrictor ; as they descend they blend together, and
form a uniform layer, which covers the outer surface of the tube.
The circular fibres are continuous above with the Inferior constrictor ; their
direction is transverse at the upper and lower parts of the tube, but oblique in
the central part.^
The muscular fibres in the upper part of the oesophagus are of a red color, and
consist chiefly of the striped variety; but below, they consist entirely of the
involuntary muscular fibre.
The cellular coat connects loosely the mucous and muscular coats.
The mucous coat is thick, of a reddish color above, and pale below. It is dis-
posed in longitudinal folds, which disappear on distension of the tube. Its
surface is studded with minute papillee, and it is covered throughout with a
thick layer of squamous epithelium.
The oesophageal glands are numerous small compound glands, scattered
throughout the tube ; they are lodged in the submucous tissue, and open upon
the surface by a long excretory duct. They are most numerous at the lower
part of the tube, where they form a ring round the cardiac orifice.
The Abdomen.
The Abdomen is the largest cavity in the body, and is separated, below, from
the pelvic cavity by the brim of the pelvis. It is of an oval form, the extremi-
ties of the oval being directed upwards and downwards ; it is wider above than
below, and measures more in the vertical than in the transverse diameter.
' Accessory slips of muscular fibres are described by Dr. Cunningham as passing between the
oesophagus and the pleura, where it covers the thoracic aorta (almost always), or the root of the
left bronchus (usually), or the back of the pericardium, or corner of the mediastinum (more rarely),
as well as other still more rare accessory fibres.— (/oitrna/ of Anal, and Phys., vol. x. p. 320.)
762
ORGANS OF DIGESTION.
Boundaries. It is bounded, in front and at tlie sides by the lower ribs, the
Transversalis muscle, and the venter illii ; behind^ bj the vertebral column, and
the Psoas and Quadratus lumborum muscles ; ahove, by the Diaphragm ; heJow
by the brim of the pelvis. The muscles forming the boundaries of the cavities
are lined upon their inner surface by a layer of fascia, differently arranged
according to the part to which it is attached.
The abdomen contains the greater part of the alimentary canal ; some of the
accessory organs to digestion, viz., the liver, pancreas, and spleen ; and the kid-
neys and suprarenal capsules. Most of these structures, as well as the wall of
the cavity in which they are contained, are covered by an extensive and compli-
cated serous membrane, the peritoneum.
The apertures found in the walls of the abdomen, for the transmission of struc-
tures to or from it, are the umbilicus^ for the transmission (in the foetus) of the
umbilical vessels ; the caval opening in the Diaphragm, for the transmission of
the inferior vena cava ; the aortic opening^ for the passage of the aorta, vena
azygos, and thoracic duct; and the oesophageal opening^ for the oesophagus and
pneumogastric nerves. Below, there are two apertures on each side : one for
the passage of the femoral vessels, and the other for the transmission of the
spermatic cord in the male, and the round ligament in the female.
Fig. 432 — The Regions of the Abdomen and their Contents.
(Edge of Costal Cartilages in dotted outline.)
Regions. For tlic convenience of description of the viscera, as well as oi
reference to the morbid condition of the contained })arts, the abdomen is artifi-
cially divided into nine regions. Thus, if two circular lines are drawn round
the body, the one parallel with the cartilages of the ninth ribs, and the other
with the highest point of tlic crests of the ilia, the abdominal cavity is divided
PERITONEUM.
763
into three zones, an upper, a middle, and a lower. If two parallel lines are
drawn from the cartilage of the eighth rib on each side, down to the centre of
Poupart's ligament, each of these zones is subdivided into three parts, a middle
and two lateral.
The middle region of the upper zone is called the epigastric {inl, over; yaar^jp,
the stomach) ; and the two lateral regions, the right and lej't hyjwchondriac {vn6,
under ; xovSpoi, the cartilages). The central region of the middle zone is the um-
bilical; and the two lateral regions, the right and left lumbar. The middle region
of the lower zone is the hypogastric or pubic region ; and the lateral regions are
the right and left inguinal. The viscera contained in these different regions are
the following (JFig. 432).
Right Hypochondriac.
The right lobe of the
liver and the gall-bladder,
the duodenum, pancreas,
hepatic flexure of the
colon, upper part of. the
right kidney, and the
right suprarenal capsule.
Right Lumbar.
Ascending colon, lower
part of the right kidney,
and some convolutions of
the small intestines.
Bight Inguinal.
The caecum, appendix
cseci, and ureter.
Epigastric Region.
The middle and pyloric
end of the stomach, left
lobe of the liver, and
lobulus Spigelii, and the
pancreas.
Umbilical Region.
The transverse colon,
part of the great omen-
tum and mesentery, trans-
verse part of the duode-
num, and some convolu-
tions of the jejunum and
ileum.
Hypogastric Region.
Convolutions of the
small intestines, the blad-
der in children, and in
adults if distended, and
the uterus during preg-
nancy.
Left Hypochondriac.
The splenic end of the
stomach, the spleen and
extremity of the pancreas,
the splenic flexure of the
colon, upper half of the
left kidney, and the left
suprarenal capsule.
Left Lumbar.
Descending colon, part
of the omentum, lower
part of the left kidney,
and some convolutions of
the small intestines.
Left Inguinal.
Sigmoid flexure of the
colon, and ureter.
The Peritoneum.
The Peritoneum (Ttfpt^ftVtu-, to extend around) is a serous membrane; and, like
all membranes of this class, a shut sac. In the female, however, it is not com-
pletely closed, the Fallopian tubes communicating with it by their free extremi-
ties ; and thus the serous membrane is continuous with their mucous lining.
The peritoneum partially invests all the viscera contained in the abdominal
and pelvic cavities, forming the visceral layer of the membrane; it is then
reflected upon the internal surface of the parietes of those cavities, forming the
parietal layer. The free surface of the peritoneum is smooth, moist, and covered
by a thin squamous epithelium ; its attached surface is rough, being connected
to the viscera and inner surface of the parietes by means of areolar tissue, called
the subperitoneal areolar tissue. The parietal portion is loosely connected with
the fascia lining the abdomen and pelvis; but more closely to the under surface
of the Diaphragm, and in the middle line of the abdomen.
In order to trace the reflections of this membrane (Fig. 433), the abdomen
having been opened, the liver should be raised and supported in that position,
and the stomach should be depressed, when a thin membranous layer is seen
passing from the transverse fissure of the liver to the upper border of the
stomach : this is the lesser or gastro-hepatic omentum. It consists of two delicate
764
ORGANS OF DIGESTION.
layers of peritoneum, an anterior and a posterior, between wliicli are continued
tlie liepatic vessels and nerves. Of tliese two layers, the anterior should first
be traced, and then the posterior.
The anterior layer descends to the lesser curvature of the stomach, and covers
its anterior surface as far as the great curvature : it descends for some distance
in front of the small intestines, and, returning upon itself to the transverse
colon, forms the external layer of the great omentum; it then covers the under
surface of the transverse colon, and, passing to the back part of the abdominal
cavity, forms the inferior layer of the transverse mesocolon. It then descends
in front of the duodenum, the aorta, and vena cava, as far as the superior
mesenteric artery, along which it passes to invest the small intestines, and,
returning to the vertebral column, forms the mesentery : whilst, on either side,
it covers the ascending and descending colon, and is thus continuous with the
Fig. 433. — The Reflections of the Peritoneum, as seen in a vertical
Section of the Abdomen.
pcritonouin lining the walls of the abdomen. From the root of the mesentery,
it descends along the front of the spine into the pelvis, and surrounds the upper
part of the rectum, wliich it holds in its position by means of a distinct fold,
the m,esorcctnrn.. Its course in the male and female now ditl'crs.
In the w,a/e, it forms a fold between the rcctiira and bladder, the recto-vesical
fold^ and ascends over the posterior surface of the latter organ as far as its
summit.
In the/ema?e, it descends into the pelvis in front of the rectum, covers a small
part of the posterior wall of the vagina, and is then reflected on to the uterus,
the fundus and body of which it covers. From the sides of the uterus, it is
PERITONEUM. 765
reflected on eacli side to tlie wall of the pelvis, forming tlie broad ligaments;
and from the anterior surface of the uterus it ascends upon the posterior wall
of the bladder, as far as its summit. From this point it may be traced, as in
the male, ascending upon the anterior parietes of the abdomen, to the under
surface of the Diaphragm; from which it is reflected upon the liver, forming
the upper layer of the coronary, and the lateral and longitudinal ligaments. It
then covers the upper and under surfaces of the liver, and at the transverse
fissure becomes continuous with the anterior layer of the lesser omentum, the
point whence its reflection was originally traced.
The posterior layer of the lesser omentum descends to the lesser curvature of
the stomach, and covers its posterior surface as far as the great curvature ; it
then descends some distance in front of the small intestines, and, returning upon
itself to the transverse colon, forms the internal layer of the great omentum; it
covers the upper surface of the transverse colon, and, passing backwards to the
spine, forms the upper layer of the transverse mesocolon. Ascending in front
of the pancreas and crura of the Diaphragm, it lines the back part of the under
surface of that muscle, from which it is reflected on to the posterior border of
the liver, forming the inferior layer of the coronary ligament. Prom the under
surface of the liver it may be traced to the transverse fissure, where it is con-
tinuous with the posterior layer of the lesser omentum, the point whence its
reflection was originally traced.
The space included in the reflections- of this layer of the peritoneum is called
the lesser cavity of the. peritoneum or cavity of the great omentum. It is bounded,
in front, by the lesser omentum, the stomach, and the descending part of the
great omentum; hehind, by the ascending part of the great omentum, the trans-
verse colon, transverse mesocolon, and its ascending layer ; ahove, by the liver ;
and helow, by the folding of the great omentum. This space communicates with
the general peritoneal cavity through the foramen of Winslow, which is situated
behind the right, or free, border of the lesser omentum.
l^h-Q, foramen of Winslow is bounded in front by the lesser omentum, inclosing
the vena portee and the hepatic artery and duct ; behind, by the inferior vena
cava; above, by the lobulus Spigelii; helow, by the hepatic artery curving for-
wards from the coeliac axis.
This foramen is nothing more than a constriction of the general peritoneal
cavity at this point, caused by the hepatic and gastric arteries passing forwards
from the coeliac axis to reach their respective viscera.
The viscera thus shown to be almost entirely invested by peritoneum are the
liver, stomach, spleen, first portion of the duodenum, the jejimum, and ileum,
the transverse colon, sigmoid flexure, upper end of the rectum, the uterus, and
ovaries.
The viscera only partially invested by peritoneum are the descending and
transverse portions of the duodenum, the ceecum, the ascending and descending
colon, the middle portion of the rectum, and the upper part of the vagina and
posterior wall of the bladder. The kidneys, suprarenal capsules, and pancreas
are covered by the membrane without receiving any special investment from it.
The lower end of the rectum, the neck, base, and anterior surface of the
bladder, the whole of the front, and the lower part of the posterior, wall of the
vagina, have no peritoneal covering.
Numerous folds are formed by the peritoneum, extending betAveen the various
organs. These serve to hold them in position, and, at the same time, inclose the
vessels and nerves proceeding to each part. Some of the folds are called ligaments,
from their serving to support the organs in position. Others, which connect
certain parts of the intestine with the abdominal wall, constitute the mesenteries ;
and lastly, those are called omenta, which proceed from the stomach to certain
viscera in its neig:hborhood.
The Ligaments, formed by folds of the peritoneum, include those of the liver,
766 ORGANS OF DIGESTION.
spleen, bladder, and uterus. They will be found described with their respective
organs.
The Omenta are the lesser omentum, the great omentum, and the gastro-
splenic omentum.
The lesser omentum [g astro -hepatic) is the duplicature which extends between
the transverse fissure of the liver and the lesser curvature of the stomach. It
is extremely thin, and consists, as before said, of two layers of peritoneum. At
the left border its two layers pass on to the end of the oesophagus ; but at the
right border, where it is free, they are continuous, and form a free rounded
margin, which contains between its layers the hepatic artery, the ductus com-
munis choledochns, and portal vein, lymphatics and the hepatic plexus of nerves
— all these structures being inclosed in loose areolar tissue, called Glisso7i's cap-
sule. Between the layers where they are attached to the stomach lie the coro-
naria ventriculi artery and the pyloric branch of the hepatic anastomosing
with it.
The great omentum (gastro-colic) is the largest peritoneal fold. It consists of
four layers of peritoneum, two of which descend from the stomach, one from its
anterior, the other from its posterior surface, and, uniting at its lower border,
descend in front of the small intestines, as low down as the pelvis ; they then
turn upon themselves, and ascend again as far as the transverse colon, where
they separate and inclose that part of the intestine. These separate layers may
be easily demonstrated in the young subject ; but, in the adult, they are more or
less inseparably blended. The left border of the great omentum is continuous
with the gastro-splenic omentum; its right border extends as far only as the
duodenum. The great omentum is usually thin, presents a cribriform appear-
ance, and always contains some adipose tissue, which, in fat subjects, accumulates
in considerable quantity. Its use appears to be to protect the intestines from the
cold, and to facilitate their movement upon each other during their vermicular
action. Between its layers is the anastomosis between the right and left gastro-
epiploica arteries.
The gastro-splenic 07nentum is the fold which connects the concave surface of
the spleen to the cul-de-sac of the stomach, being continuous by its lower border
with the great omentum. It contains the splenic vessels and vasa brevia.
The Mesenteeies are, the mesentery proper, the mesoccecum, the ascending
transverse, and descending mesocolon, the sigmoid mesocolon, and the meso-
rectum.
The mesentery [fiiaov, Ivfifiov), so called from being connected to the middle of
the cylinder of the small intestine, is the broad fold of peritoneum which con-
nects the convolutions of the jejunum and ileum with the posterior wall of the
abdomen. Its root, the part connected with the vertebral column, is narrow,
about six inches in length, and directed obliquely from the left side of the second
lumbar vertebra to the right sacro-iliac symphysis. Its intestinal border is
much longer ; and here its two layers separate, so as to inclose the intestine, and
form its peritoneal coat. Its breadth, between its vertebral and intestinal border,
is about four inches. Its up2:)er border is continuous with the under surface of
the transverse mesocolon; its lower border, with the peritoneum covering the
caecum and ascending colon. It serves to retain the small intestines in their
position, and contains between its layers the mesenteric vessels and nerves, the
lacteal vessels and mesenteric glands.
The mesocsecum, when it exists, serves to connect the back part of the cascum
with the right iliac fossa; more frequently, the peritoneum passes merely in front
of this portion of the large intestine.
The ascending mesocolon is the fold which connects the back part of the
ascending colon witli the posterior wall of the abdomen; and the descending
mesocolon retains the descending colon in connection with the posterior abdomi-
nal wall; more frequently, the peritoneum merely covers the anterior surface
and sides of these two portions of the intestine.
THE STOMACH. 767
The transverse mesocolon is a broad fold, wliicli connects the transverse colon
with the posterior wall of the abdomen. It is formed bj the two ascending
layers of the great omentum, which, after separating to surround the transverse
colon, join behind it, and are continued backwards to the spine, where they
diverge in front of the duodenum, as already mentioned. This fold contains
between its layers the vessels which supply the transverse colon.
The sigmoid mesocolon is the fold of peritoneum which retains the sigmoid
flexure in connection with the left iliac fossa.
The mesorectum is the narrow fold which connects the upper part of the rec-
tum with the front of the sacrum. It contains the hsemorrhoidal vessels.
The a2opendices epiploicse are small pouches of the peritoneum filled with fat,
and situated along the colon and upper part of the rectum. They are chiefly
appended to the transverse colon.
The Stomach.
The Stomach is the principal organ of digestion. It is the most dilated part
of the alimentary canal, serving for the solution and reduction of the food, which
constitutes the process of chymification. It is situated in the left hypochondriac,
the epigastric, and part of the right hyjiochondriac regions. Its form is irregu-
larly conical, curved upon itself, and presenting a rounded base, turned to the left
side. It is placed immediately behind the anterior wall of the abdomen, above
the transverse colon, below the liver and the Diaphragm. Its size varies con-
siderably in different subjects, and also according to its state of distensions.
When moderately full, its transverse diameter is about twelve inches, its verti-
cal diameter about four. Its weight, according to Clendenning, is about four
ounces and a half. It presents for examination two extremities, two orifices, two
borders, and two surfaces.
Its left extremity is called the greater^ or sjjlenic end. This is the largest part
of the stomach, and extends two or three inches to the left of the point of
entrance of the oesophagus. This expanded part is called the great cul-de-sac,
ov fundus. It lies behind the lower ribs, in contact with the spleen, to which it
is connected by the gastro-splenio omentuni.
The lesser or pyloric end is much smaller than the fundus, and situated on a
plane anterior and inferior to it. It lies in contact with the wall of the "abdo-
men, the under surface of the liver, and the neck of the gall-bladder.
The oesophageal or cardiac orifice communicates with the oesophagus; it is the
highest part of the stomach, and somewhat funnel-shaped.
The pyloric orifice communicates with the duodenum, the aperture being
guarded by a kind of valve — the pylorus.
The lesser curvature extends between the oesophageal and pyloric orifices,
along the upper border of the organ, and is connected to the under surface of
the liver by the lesser omentum.
The greater curvature extends between the same two points, along the lower
border, and gives attachiment to the great omentum. The surfaces of the organ
are limited by these two curvatures.
The anterior surface is directed upwards and forwards, and is in relation with
the Diaphragm, the under surface of the left lobe of the liver, and with the
abdominal parietes, in the epigastric region.
The posterior surface is directed downwards and backwards, and is in relation
with the pancreas and great vessels of the abdomen, the crura of the Diaphragm,
and the solar plexus.
The stomach is held in position by the lesser omentum, which extends from
the transverse fissure of the liver to its lesser curvature, and by a fold of perito-
neum, which passes from the Diaphragm on to the oesophageal end of the
stomach, the gastro-phrenic ligament: this constitutes the most fixed point of
the stomach, whilst the pyloric end and greater curvature are the most movable
768
ORGA]S"S OF DIGESTION.
parts ; lienco wlien tlie stomach becomes greatly distended, tlie greater curvature
is directed forwards, wliilst tlie anterior and posterior surfaces are directed, tlie
former upwards, and tlie latter downwards.
Alterations in Position. There is no organ in the body tlie position and connections of
which present such frequent alterations as the stomach. During insinration, it is displaced
downwards by the descent of the Diaphragm, and elevated by the pressure of the abdominal
muscles during expiration. Its position in relation to the surrounding viscera is also changed,
according to the empty or distended state of the organ. When empty, it occupies only a small
part of the left hypochondriac region, the spleen lying behind it ; the left lobe of the liver covers
it in front, and the under surface of the heart rests upon it above, and in front ; being separated
from it by the left lobe of the liver, besides the diaphragm and pericardium. This close relation
between the stomach and the heart explains the fact that, in gastralgia, the pain is generally
referred to the heart, and is often accompanied by palpitation and intermission of the pulse.
When the stomach is distended the Diaphragm is forced upwards, contracting the cavity of the
chest ; hence the dyspnoea complained of, from inspiration being impeded. The heart is also
displaced upwards ; hence the oppression in this region, and the palpitation experienced in extreme
distension of the stomach. Pressure from ivithout, a?, from tight lacing, pushes the stomach
down towards the pelvis. In disease, also, the position and connections of the organs may be
greatly changed, from the accumulation of fluid in the chest or abdomen, or from alteration in
size of any of the surrounding viscera.
On looking into the pyloric end of the stomach, the mucous membrane is
found projecting inwards in the form of a circular fold, the pylorus, leaving a
narrow circular aperture, about half an inch in diameter, by which the stomach
communicates with the duodenum.
Fig. 434. — The Mucous Membrane of the Stomach and Duodenum, with the Bile Ducts.
r^tur
Tho pylorvs is formed by a reduplication of llie mucous membrane of the
stomacli, containing numerous muscular fibres, which are aggregated into a
thick circular ring, the longitudinal fibres and serous membrane being continued
over the fold without assisting in its formation. The aperture is occasionally
THE STOMACH.
7G9
oval. Sometimes, the circular fold is replaced by t-\^o crescentic folds, placed,
one above, and the other below, the pyloric oriiice ; aud, more rarely, there is
only on§ crescentic fold.
Structure. The stomach consists of four coats : a serous, a muscular, a cellu-
lar, and a mucous coat, together with vessels and nerves.
The serous coat is derived from the peritoneum, and covers the entire surface
of the organ, excepting along the greater and lesser curvatures, at the points of
attachment of the greater and lesser omenta ; here the two layers of peritoneum
leave a small triangular space, along which the nutrient vessels and nerves pass.
The muscular coat (Fig. 435) is situated immediately beneath the serous cover-
ing. It consists of three sets of fibres: longitudinal, circular, and oblique.
The longitudinal fibres are most superficial; they are continuous with the
longitudinal fibres of the oesophagus, radiating in a stellate manner from the
cardiac orifice. They are most distinct along the curvatures, especially the lesser ;
but are very thinly distributed over the surfaces. At the pyloric end, they are
more thickly distributed, and continuous with the longitudinal fibres of the
small intestine.
Fisr. 435.— The Muscular Coat ef the Stomach.
The circular fibres form a uniform layer over the whole extent of the stomach,
beneath the longitudinal fibres. At the pylorus they are most abundant, and
are aggregated into a circular ring, which projects into the cavity, and forms,
with the fold of mucous membrane covering its surface, the pyloric valve.
The oblique fibres are limited chiefly to the cardiac end of the stomach, where
they are disposed as a thick uniform layer, covering both surfaces, some passing
obliquely from left to right, others from riglit to left, round the cardiac orifice.
The cellular coat consists of a loose, filamentous, areolar tissue, connecting the
mucous and muscular layers. It is sometimes called the submucous coat. It
supports the bloodvessels previous to their distribution to the mucous mem-
brane ; hence it is sometimes called the vascular coat.
The mucous membrane of the stom.ach is thick ; its surface smooth, soft, and
velvety. During infancy, and immediately after death, it is of a pinkish tinge ,
but in adult life and in old age, it becomes of a pale straw or ash-gray color. It
is thin at the cardiac extremity', but thicker towards the pylorus. During the
49
770
ORGANS OF DIGESTION.
contracted state of tlie organ, it is thrown into numerous plaits or rugge, wliicli,
for tke most part, have a longitudinal direction, and are most marked towards
the lesser end of the stomach, and along the greater curvature (Fig, 434),
These folds are entirely obliterated when the organ becomes distended.
Structure of the mucous monhrane (Fig. 436), When examined with a lens,
the inner surface of the mucous membrane presents a peculiar honeycomb appear-
ance, from being covered with small shallow depressions or alveoli, of a poly-
gonal or hexagonal form, which vary from x^o 'to 350 of an inch in diameter,
and are separated by slightly elevated ridges. In the bottom of the alveoli are
seen the orifices of minute tubes, the gastric follicles^ which are situated perpen-
dicularly side by side, in the entire substance of the mucous membrane. They
are short, and simjoly tubular in character, towards the cardia ; but at the pyloric
end, they are longer, more thickly set, convoluted, and terminate in dilated
saccular extremities, or are subdivided into from two to six tubular branches.
Fig. 436. — Minute Anatomy of Mucous jNIembrane of Stomach.
" ' " Orifice of Tube
E^Ctheiial particles
Blood Vassels
Dr. "Watney has pointed out that these convoluted or coiled tubes form the
transition from the simple tubular follicles to the convoluted glands of Brunner
which lie immediately below the pylorus. The gastric follicles are composed of a
homogeneous basement membrane, lined upon its free surface by a layer of cells,
which differ in their character in different parts of the stomach. Towards the
pylorus these tubes are lined throughout with columnar epithelium ; they are
termed the mucous glands^ and are supposed to secrete the gastric mucus. In
other parts of the organ, the deep part of each tube is filled with nuclei and a
mass of granules ; above these are a mass of nucleated cells, the upper fourth of
the tube being lined by columnar epithelium. These are called the peptic glands^
and are the supposed agents in the secretion of the gastric juice.
Simple follicles are found in greater or less number over the entire surface of
the mucous membrane; they arc most numerous near the pyloric end of the
stomach, and are especially distinct in early life. The epithelium lining the
mucous membrane of the stomach and its alveoli is of the columnar variety.
Vessels and Nerves. The arteries supplying the stomach are, the coronaria
ventriculi, the pyloric and right gastro-epiploic branches of the hepatic, the
left gastro-epiploic and vasa brevia from the splenic. They supply the muscular
coat, ramify in the submucous coat, and are finally distributed to the mucous
membrane. The arrangement of the vessels in the mucous membrane is some-
what peculiar. The arteries break u]^ at the base of the gastric tubules into a
plexus of fine capillaries which run upwards, betwcn the tubules, anastomosing
with each other, and ending in a plexus of larger capillaries, which surround
the monlh.s of the tubes, and also form hexagonal meshes around the alveoli.
From these latter the veins arise, which pursue a straight course back to the
submucous tissue, between the tubules, to terminate in the splenic and portal
veins. The lymphatics arc numerous; they consist of a superficial and deep set,
which pass through the lymphatic glands found along the two curvatures of the
SMALL INTESTINES. 771
organ. Tlie nerves are tlie terminal brandies of the riglit and left pneumogas-
tric, the former being distributed upon the back, and the latter upon the front
part of the organ. A great number of branches from the sympathetic also sup-
ply the organ.
The Small Intestines.
The Small Intestine is that part of the alimentar}^ canal in which the chyme
is mixed with the bile, the pancreatic jaice, and the secretions of the various
glands imbedded in the mucous membrane of the intestine, and where the
separation of the nutritive principle of the food, the chyle, is effected: this
constitutes chylification.
The small intestine is a convoluted tube, about twenty feet in length, which
gradually diminishes in size from its commencement to its termination. It is
contained in the central and lower parts of the abdominal and pelvic cavities,
surrounded above and at the sides by the large intestine ; in relation, in front,
with the great omentum and abdominal parietes ; and connected to the spine by
a fold of peritoneum, the mesentery. The small intestine is divisible into three
portions: the duodenum, jejunum, and ileum.
The duodenum has received its name from being about equal in length to the
breadth of twelve fingers (eight or ten inches). It is the shortest, the widest,
and the most fixed part of the small intestine; it has do mesentery, and is only
partially covered by the peritoneum. Its course presents a remarkable curve,
somewhat like a horseshoe in form ; the convexity being directed towards the
right, and the concavity to the left, embracing the head of the pancreas. Com-
mencing at the pylorus, it ascends obliquely upwards and backwards to the
under surface of the liver; it then descends in front of the right kidney, and
passes nearly transversely across the front of the spine, terminating in the
jejunum on the left side of the second lumbar vertebra. Hence the duodenum
has been divided into three portions : ascending, descending, and transverse.
The first, or ascending portion (Fig. 437), about two inches in length, is free,
movable, and nearly completely invested by the peritoneum, which forms the
lesser omentum. It is in relation, above and in front, with the liver and neck
of the gall-bladder; behind, with the vessels which run between the layers of
the lesser omentum, viz., the hepatic artery and duct, and vena port&e. This
portion of the intestine is usually found, after death, stained with biie, especially
on its anterior surface.
The second, or descending portion^ about three inches in length, is firmly fixed
by the peritoneum and pancreas. It passes from the neck of the gall-bladder
vartically downwards, in front of the right kidney, as far as the third lumbar
vertebra. It is covered by peritoneum only on its anterior surface. It is in
relation, in front, with the right arch of the colon and the meso-colon; behind
with the front of the right kidney; at its inner side is the head of the pancreas,
and the ductus communis choledochus. The common bile duct and the pan-
creatic duct perforate the inner side of this portion of the intestine obliquely,
a little below its middle.
The third, or transverse portion^ the longest and narrowest part of the duo-
denum, passes across the front of the spine, ascending from the third to the
second lumbar vertebra, and terminating in the jejunum on the left side of that
bone. In front, though at some distance from it, is the descending layer of the
transverse meso-colon, or the divergence of the two layers of that structure,
and it is crossed by the superior mesenteric vessels ; behind, it rests upon the
aorta, the vena cava, and the crura of the Diaphragm ; above it, is the lower
border of the pancreas, the superior mesenteric vessels passing forwards between
the two.
Vessels and Nerves. The arteries supplying the duodenum are the pyloric
and pancreatico- duodenal branches of the hepatic, and inferior pancreatico-
772
ORGANS OF DIGESTION.
duodenal branch of tlie superior mesenteric. The veins terminate in the gastro-
duodenal and superior mesenteric. The nerves are derived from the solar plexus.
The jejunum {jejunus^ empty), so called from being usually found empty after
death, includes the upper two-fifths of the rest of the small intestine. It com-
mences at the duodenum, on the left side of the second lumbar vertebra, and
terminates in the ileum ; its convolutions being chiefly confined to the umbilical
and left iliac regions. The jejnnum is wider, its coats thicker, more vascular,
and of a deeper color than those of the ileum; but there is no characteristic
mark to distinguish the termination of the one and the commencement of the
other.
Fig. 437. — Kelations of the Duodenum. (The Pancreas has been cut away, except its head.
¥ ¥ y^^^v^^^^^^^'i^
The ileura (duiv, to hoist), so called from its numerous coils or convolutions,
includes the remaining three-fifths of the small intestine. It occu])ics chiefly
the umbilical, liypogastric, right iliac, and occasionally the jiclvic regions, and
terminates in the right iliac fossa by opening into the inner side of the com-
monccrricnt of the large intestine. The ileum is narroAvcr, its coats thinner and
less vascular than those of the jejunum; a given length of it weighing less than
the same length of the jejunum.
tSiruclnre. The wall of the small intestine is com])()sc(l of four coats: serous,
muscular, cellular, and mucous.
TliC serous coat is derived from the [jci'itoncum, Tiic first, or ascending
SMALL INTESTINES. ' 773
portion of tlie duodenum, is almost completely surrounded by that membrane ;
the second, or descending portion, is covered by it only in front ; and the third,
or transverse, portion lies behind the descending layer of the transverse meso-
colon, by which it is covered in front. The remaining portion of the small
intestine is surrounded by the peritoneum, excepting along its attached or
mesenteric border ; here a space is left for the vessels and nerves to pass to
the gut.
The muscular coat consists of two layers of fibres, an external or longitudinal,
and an internal or circular layer. The lonyitudinal fibres are thinly scattered
over the surface of the intestine, and are most distinct along its free border.
The circular fibres form a thick, uniform layer; they surround the cylinder of
the intestine in the greater part of its circumference, but do not form complete
rings. The muscular coat is thicker at the upper than at the lower part of the
small intestine.
The cellular^ or submucous coat, connects together the mucous and muscular
layers. It consists of a loose, filamentous, areolar tissue, which forms a nidus
for the subdivision of the nutrient vessels, previous to their distribution to the
mucous surface.
The m^ucous membrane is thick and highly vascular at the upper part of the
small intestine, but somewhat paler and thinner below. It presents for exami-
nation the following constituents : —
Epithelium. Simple follicles.
Valvuh"e conniventes. i Duodenal glands.
Villi. Glands, -s Solitarj^ glands.
( Agminate or Peyer's glands.
The ejDithelhwi, covering the mucous membrane of the small intestine, is of
the columnar variet}^
The valvulse conniventes (valves of Kerkring) are reduplications of foldings of
the mucous membrane and submucous tissue, containing no muscular fibres.
They extend transversely across the cylinder of the intestine for about three-
fourths or five -sixths of its circumference. The larger folds are about two inches
in length, and two-thirds of an inch in depth at their broadest part ; but the
greater number are of smaller size. The larger and smaller folds alternate with
each other. They are not found at the commencement of the duodenum, but
begin to appear about one or two inches beyond the pylorus. In the lower part
of the descending portion, below the point where the common choledoch and pan-
creatic ducts enter the intestine, they are very large and closely approximated.
In the transverse portion of the duodenum and upper half of the jejunum, they
are large and numerous ; and from this point, down to the middle of the ileum,
they diminish considerably in size. In the lower part of the ileum, they almost
entirely disappear; hence the comparative thinness of this portion of the intes-
tine, as compared with the duodenum and jejunum. The valvule conniventes
retard the passage of the food along the intestines, and afibrd a more extensive
surface for absorption.
The villi are minute, highly vascular processes, projecting from the mucous
membrane of the small intestine throughout its whole extent, and giving to its
surface a velvety appearance. In shape some are triangular and laminated,
others conical or cylindrical, with clubbed or filiform extremities. They are
largest and most numerous in the duodenum and jejunum, and become fewer
and smaller in the ileum. Krause estimates their number in the upper part of
the small intestine at from fifty to ninety in a square line; and in the lower
part from forty to seventy ; the total number for the whole length of the intes-
tine being about four millions.
The structure of the villi has been studied recently by many eminent anato-
mists. We shall here follow the description of Dr. Watney,^ whose researches
• Fliil. Trans, vol. clxvi. pt. 2.
774
' ORGANS OF DIGESTION.
liave a most important bearing on the physiology of that which is the peculiar
function of this part of the intestine, the absorption of fat.
The essential parts of a villus are the lacteal vessel, the bloodvessels, the epi-
thelium, the basement, membrane and. muscular tissue of the mucosa, and the
cells and reticular tissue which fill up the interspaces.
The lacteals are situated in the axis of the villi. They arise either by clubbed
or dilated extremities, or else by loops. In some few cases they are double, and
in animals multiple. They are composed of a single layer of epithelium.
Forming a sheath or adventitia to this epithelium, penetrating between the
epithelial cells, is (according to Dr. Watney) an abundant reticulum, along
which he believes the fat-granules to travel. The pale muscular fibres which
Fig. 438. — Diagrammatic Section of a Villus.
e/p. Epithelium only partially shadod in. I, Central chyle-vessel. The cells forming the vessel have been lei-s
shaded to distinguish them from the cells of the parenchyma of the villus, m. Muscle fibres running up by the side
of the chyle-vessel. It ■will be noticed that each muscle fibre is surrounded by the reticulum, and by this reticulum'
the muscles are attached to the cells forming the membrana propria,, as at e' , or to the reticulum of the villus. Ic.
Lymi)h corpuscles, marked by a spherical nucleus and a clear zone of protoplasm. V . Upper limit of the chyle-
ves-el. e, e, e.' . Cells forming the ineiiibrana propria. It will be seen that there is hardly any difference between
the tells of the parenchyma, the eudothelium of thet/^yier part of the chyle-vessel, and the colls of the membrana
propria, v. Bloodvessels, z. Dark lino at the base of the epithelium formed by the reticulum. It will bo seen
that the reticulum jienetrates between all the other elements of the villus. The reticulum contains thickenings or
" nodal jioints." The diagram shows that the cells of the .upper part of the villus are larger and contain a larger
zone of i)rotoplasm than those of the lower part. The cells of the upper part of the chyle-vessel differ somewhat
from tliose of the lower part, \\\ that thry more nearly resemble tho cells of the parcndiyma.
play so important a part in the nnatomy and functions of the villus are derived
from the miiscularis mucosyf), and they terminate in close relation with the cells
of the villus {i. e. the cells which lie in the interstices of the capillary network
outside tlic lacteal), where they appear to be continuous with the reticulum.
Tho capillaries lie around the villus, and arc also provided with a sheath of
reticular tissue. ''I'hc colls of the villus are large masses of proi()i)liisiii with an
oval nucleus. Tluiir size nnd the shape of their nucleus, as Avell as their
beliavi(;r towards reagents, distinguish them, according to Dr. Watney, from
SMALL INTESTINES.
775
Fig. 439.— Two Villi magnified.
tlie Ijmpli corpuscles which are also met with in smaller numbers, and which
are much smaller and with a spherical nucleus. Transitional forms, however,
of all kinds are met with between the lymph corpuscles and the cells of the
villus. All these points are illustrated by the accompanying diagram by Dr.
Watney (Fig. 438), for which I have to express my best thanks to him, and a
comparison with Fig. 439 will show the chief points in which the new differs
from the old description.
Tlie simple follicles^ or crypts of Lieberktihn, are found in considerable num-
bers over every part of the mucous membrane of the small intestine. They
consist of minute tubular depressions of the
mucous membrane, arranged perpendicu-
larly to the surface, upon which they open
by small circular apertures. They may be
seen with the aid of a lens, their orifices
appearing as minute dots, scattered between
the villi. Their walls are thin, consisting
of a layer of basement membrane, lined by
cylilidrical epithelium, and covered on their
exterior by capillary vessels. Their con-
tents vary, even in health, and the purpose
served by their secretion is still very doubt-
ful.
The duodenal^ or Brunner's glands, are
limited to the duodenum and commence-
ment of the jejunum. They are small, flattened, granular bodies, embedded in
the submucous areolar tissue, and open upon the surface of the mucous mem-
brane by minute excretory ducts. They are most numerous and largest near
the pylorus. They may be compared to the elementary lobules of a salivary
gland spread out over a broad surface, instead of being collected in a mass. In
structure they resemble the pancreas.
iVaCZeu*
As^Ty
Fig. 440.-
-Transverse Section through the equatorial plane of three of Peyer's Follicles from
the Rabbit.
a. Capillary network. 6. Larj-e circular vessels.
The solitary glands {cflandulse solitarise) are found scattered throughout the
mucous membrane of the small intestine, but are most numerous in the lower
77G
ORGANS OF DIGESTION.
part of the ileum. They are small, round, whitish bodies, from half a line to a
line in diameter. Their free surface is covered with villi, and each gland is
surrounded by openings of follicles of Lieberkuhn. They are now recognized as
lymphoid follicles, and consist of a dense interlacing retiform tissue permeated
with an abundant capillary network (Fig. 440). The interspaces of the retiform
tissue are continuous with larger lymph-spaces at the base of the follicle through
which they communicate with the lacteal system, and they contain lymph-cor-
puscles in their interior. They are situated partly in the corium of the mucous
membrane, partly penetrate its muscular layer, and project into the epithelial
layer. The villi, which are situated on them, are generally absent from the
very summit (or "cupola," as Frey calls it) of the follicle.
Fig. 441. — Patch of Peyer's Glands.
From the lower part of the Ileum.
Fig. 442. — A portion of the same magnified.
H
Fig. 443. — Vertical Section of one of Peyer's Patches from Man, injected through its
lymphatic canals.
fi. Villi with thflr chylp-pjiHKnirnH. h. Folliclos of T.inbcikiilin. c. Musciiliiris nuiocisjo. (/. Cupola or apex of folli-
cloH. e. McHlal zone of foUlcleH. /. r.aHO of follirlos. {/. Points of exit of tlio cliylo-paKsa!,'os from the villi, and
entranco Into tlio tnio rnucoiiH inornbiiuiG. h. Kotiform ariaiiffoiiiont of the lymphatics in tlio iiiosial zone. i. Course
of the lattor nt tho haHo of tho follicloH. 7(. Confluonco of tho lymphatics opening into the vessels of the submucous
tlHHiio. I. Follicular Ukkiio of the latter.
Pe.ypr''s f /lands (Figs. 441—1-48) may bo rcgarrlcd as aggregations of solitary
glands, forming circular or oval patches from twenty to thirty in number
and
LARGE INTESTINE.
777
varying in lengtli from half an inch to four inclies. They are largest and most
numerous in the ileum. In the lower part of the jejunum they are small, of a
circular form and few in number. They are occasionally seen in the duodenum.
They are placed lengthwise in the intestine, covering the portion of the tube
most distant from the attachment of the mesentery. Each patch is formed of a
group of the above described lymphoid follicles covered with mucous membrane.
Bach is surrounded by a zone, or wreath of simple follicles, and the interspaces
between them are covered with villi. The mucous and submucous coats of the
intestine are intimately adherent, and highly vascular, opposite the Peyerian
glands. They are largest and most developed during the digestive process.
The Laege Intestine.
The Large Intestine extends from the termination of the ileum to the anus.
It is about five feet in length, being one-fifth of the whole extent of the intestinal
canal. It is largest at its commencement at the cascum, and gradually diminishes
as far as the rectum, where there is a dilatation of considerable size, just above
the anus. It differs from the small intestine in its greater size, its more fixed
position, and its sacculated form. The large intestine, in its course, describes an
arch, which surrounds the convolutions of the small intestine. It commences in
the right iliac fossa, in a dilated part, the c^cum. It ascends through the right
lumbar and hypochondriac regions to the under surface of the liver; passes
transversely across the abdomen, on the confines of the epigastric and umbilical
regions, to the left hypochondriac region; descends through the left lumbar
region to the left iliac fossa, where it becomes convoluted, and forms the sigmoid
flexure ; finally, it enters the pelvis, and descends along its posterior wall to the
anus. The large intestine is divided into the csecum, colon, and rectum.
The Csecum [csecus, blind) (Fig. 444) is the large blind pouch, or cul-de-sac, in
which the large intestine commences. It is the most dilated part of the tube.
Fig. 444 — The Caecum and Colon laid open to show the Ileo-Csecal Yalve.
measuring about two and a half inches, both in its vertical and transverse
diameters. It is situated in the right iliac fossa, immediately behind the anterior
abdominal wall, being retained in its place by the peritoneum, which passes over
its anterior surface and sides; its posterior surface being connected by loose
778
ORGANS OF DIGESTION,
areolar tissue with tlie iliac fascia. Occasionally, it is almost completely sur-
rounded by peritoneum, which forms a distinct fold, the mesoceecum connecting-
its back part with the iliac fossa. When this fold exists, the ceecum obtains
considerable freedom of movement. Attached to its lower and back part is the
appendix vermiformis, a long, narrow, worm-shaped tube, the rudiment of the
lengthened caecum found in all the mammalia, except the orang-outang and
wombat. The appendix varies from three to six inches in length, its average
diameter being about equal to that of a goosequill. It is usually directed up-
wards and inwards behind the cascum, coiled upon itself, and terminates in a
blunt point, being retained in its position by a fold of peritoneum, which some-
times forms a mesentery for it. Its canal is small, and communicates with the
ceecum by an orifice, which is sometimes guarded with an incomplete valve. Its
coats are thick, and its mucous lining furnished with a large number of solitary
glands.
Fig. 445. — Diagram of the relations of the Large Intestine and Kidney from behind.
The parts uncovered by Peritoneum are shown unshaded.
% .«"' ( M ^y
ASCEND *; ^'/ /
Ileo-csecal Valve. The lower end of the ileum terrfiinates at the inner and
back part of the large intestine, opposite the junctioji of the ctecum with the^
colon. At this point the mucous membmne forms two valvular folds, which
j)rqject into the large intestine, and are separated from each other by a narrow
elongated aperture. This is the ilco-Ci3ecal valve [valwla Bauhini). Each fold
is semilunar in form. The upper one, nearly horizontal in direction, is attached
by its convex border to the point of junction of the ileum with the colon ;^ tlie
lower segment, to the point of junction of the ileum with the cfficum. Their
free concave margins project into the intestine, separated from one another by a
narrow slit-like aperture, directed transversely. At each end of this aperture
the two segments of tlio valvo coalesce, and are continued as a narrow mem-
branous ridge around the canal of the intestine for a short distance, forming
LARGE INTESTINE. 779
the /r«?ia, or retinacula of tlie valve. The left end of this aperture is rounded ;
the right end is narrow and pointed.
Each segment of the valve is formed bj a reduplication of the mucous mem-
brane and of the circular muscular fibres of the intestine, the longitudinal fibres
and peritoneum being continued uninterruptedly across from one intestine to
the other. When these are divided or removed, the ileum may be drawn out-
wards, and all traces of the valve will be lost, the ileum appearmg to open into
the large intestine by a funnel-shaped orifice of large size.
The surface of each segment of the valve directed towards the ileum is covered
with villi, and presents the characteristic structure of the mucous membrane of
the small intestine ; whilst that turned towards the large intestine is destitute
of villi, and marked with the orifices of tlie numerous tubuli peculiar to the
membrane in the large intestine. These difl'erences in structure continue as far
as the free margin of the valve.
When the C93cum is distended, the margins of the opening are approximated,
so as to prevent any reflux into the ileum.
The colon is divided into four parts: the ascending, transverse, descending,
and the sigmoid flexure.
The ascending colon is smaller than the caBCum. It passes upwards from the
right iliac fossa to the under surface of the liver, on the right of the gall-bladder,
where it bends abruptly inwards to the left, forming the hepatic flexure. It is
retained in contact with the posterior wall of the abdomen by the peritoneum,
which covers its anterior surface and sides, its posterior surface being connected
by loose areolar tissue with the Quadratus lumborum and right kidney (Figs.
445, 446); sometimes the peritoneum almost completely invests it, and forms a
distinct but narrow mesocolon. It is in relation, in front, with the convolutions
of the ileum and the abdominal parietes ; behind, it lies on the Quadratus lum-
borum muscle and right kidney.
The transverse colon^ the longest part of the large intestine, passes transversely
from right to left across the abdomen, opposite the confines of the epigastric and
umbilical zones, into the left hypochondriac region, where it curves downwards
beneath the lower end of the spleen, forming the splenic flexure. In its course
it describes an arch, the concavity of which is directed backwards towards the
vertebral column, hence the name, transverse arch of the colon. This is the most
movable part of the colon, being almost completely invested by peritoneum, and
connected to the spine behind by a large and wide duplicature of that membrane,
the transverse mesocolon. It is in relation, by its upper surface, with the liver
and gall-bladder, the great curvature of the stomach, and the lower end of the
spleen; by its under surface, with the small intestines; by its anterior surface,
with the anterior layers of the great omentum and the abdominal parietes ; by
its posterior surface, with the transverse mesocolon.
The descending colon passes almost vertically downwards through th^ left
hypochondriac and lumbar regions to the upper part of the left iliac fossa,
where it terminates in the sigmoid flexure. It is* retained in position by the
peritoneum, which covers its anterior surface and sides, its posterior surface
being connected by areolar tissue with the left crus of the Diaphragm, the left
kidney, and the Quadrajfus lumborum (Figs. 445, 446). It is smaller in calibre
and more deeply placed than the ascending colon.
The sigmoid flexure is the narrowest part of the colon ; it is situated in the
left iliac fossa, commencing from the termination of the descending colon, at
the margin of the crest of the ilium, and ending in the rectum, op]3osite the left
sacro-iliac symphysis. It curves in the first place upwards, and then descends
vertically, and to one or the other side, like the letter S — hence its name. It is
retained in its place by a loose fold of peritoneum, the sigmoid mesocolon. It
is in relation, in front, with the small intestines and abdominal parietes; behind,
with the iliac fossa.
780
ORGANS OF DIGESTION.
The Rectum is the terminal part of the large intestine, and extends from the
sigmoid flexure to the anus; it varies in length from six to eight inches, and has
received its name from being less flexuous than any other part of the intestinal
canal. It commences opposite the left sacro-iliac symphysis, passes obliquely
downwards from left to right to the middle of the sacrum, forming a gentle
curve to the right side; then, regaining the middle line, it descends in front of
Fig. 446.
-The relations of the Viscera and Large Vessels of the Abdomen.
(Seen from behind.)
RECEP-ACULUf/.niYLl
the lower part of the sacrum and coccyx, and, near the extremity of the latter
bone, inclines backwards to terminate at the anus, being curved both in the
lateral and antero-posterior directions. The rectum is, therefore, not straight,
the upper part being directed obliquely from the left side to the median line,
the middle portion being curved in the direction of the hollow of the sacrum
and coccyx, and the lower portion presenting a short curve in the opposite
direction. The rectum is cylindrical, not sacculated like the rest of the large
intestine; it is narrower at its upper part than the sigmoid flexure, gradually
increases in size as it descends, and immediately above the anus presents a
considerable dilatation, capable of acquiring an enormous size. The rectum is
divided into three portions : upper, middle, and lower.
Tlie upper portion^ which includes about half the length of the tube, extends
oblif[uc1y from the left sacro-iliac sym])hysis to the middle of tJie third piece of
the sacrum. It is almost completely surrounded by peritoneum, and connected
to the sacrum behind by a duplicnture of that membrane, the mesorecium. It
is in relation behind with the Pyriformis muscle, the sncral plexus of nerves,
and the branches of the internal iliac artery of the left side, which separate it
LARGE INTESTINE. 781
from tlie sacrum and sacro-iliac sympliysis ; in front it is separated, in tlie male,
from tlie posterior surface of the bladder ; in tlie female, from the posterior
surface of the uterus, and its appendages, by some convolutions of the small
intestine.
The middle portion of the rectum is about three inches in length, and extends
as far as the tip of the coccj^x. It is closely connected to the concavity of the
sacrum, and covered by peritoneum only on the upper part of its anterior surface.
It is in relation, in front, in the male, with the triangular portion of the base of
the bladder, the vesiculee seminales, and vasa deferentia ; more anteriorly, with
the under surface of the prostate. In the female, it is adherent to the posterior
wall of the vagina.
The lower 'portion is about an inch or an inch and a half in length ; it curves
backwards at the fore part of the prostate gland, and terminates at the anus.
This portion of the intestine receives no peritoneal covering. It is invested by
the Internal sphincter, supported by the Levatores ani muscles, and surrounded
at its termination by the External sphincter. In the male, it is separated from
the membranous portion and bulb of the urethra by a triangular space ; and in
the female, a similar space intervenes between it and the vagina. This space
forms by its base the perineum.
Structure. The large intestine has four coats, serous, muscular, cellular, and
mucous.
The serous coat is derived from the peritoneum, and invests the different por-
tions of the large intestine to a variable extent. The c^cum is covered only on
its anterior surface and sides ; more rarely, it is almost completely invested, being-
held in its position by a duplicature, the mesocsecum. The ascending and de-
scending colon are usually covered only in front. The transverse colon is almost
completely invested, the parts corresponding to the attachment of the great
omentum and transverse mesocolon being alone excepted. The sigmoid flexure
is nearly completely surrounded, the point corresponding to the attachment of
the sigmoid mesocolon being excepted. The upper part of the rectum is almost
completely invested by the peritoneum ; the middle portion is covered only on
its anterior surface ; and the lower portion is entirely devoid of any serous cov-
ering. In the course of the colon, and upper part of the rectum, the peritoneal
coat is thrown into a number of small pouches filled with fat, called appendices
epiploicse. They are chiefly appended to the transverse colon.
The muscular coat consists of an external longitudinal and an internal circular
layer of muscular fibres.
The longitudinal fibres are not found as a uniform layer over the whole surface
of the large intestine. In the csecum and colon, they are especially collected into
three fiat longitudinal bands, each being about half an inch in width. These
bands commence at the attachment of the appendix vermiformis to the caecum ;
one, the posterior, is placed along the attached border of the intestine ; the ante-
rior band, the largest, becomes inferior along the arch of the colon, where it
corresponds to the attachment of the great omentum, bat is in front in the
ascending and descending colon and sigmoid flexure ; the third, or lateral band,
is found on the inner side of the ascending and descending colon, and on the
under border of the transverse colon. These bands are nearl}^ one-half shorter
than the other parts of the intestine, and serve to produce the sacculi which are
characteristic of the cascum and colon ; accordinglj^, when they are dissected off,
the tube can be lengthened, and its sacculated character becomes lost. In the
sigmoid flexure, the longitudinal fibres become more scattered, but upon its
lower part, and round the rectum, they spread out, and form a thick uniform
layer.
The circular fibres form a thin layer over the csecum and colon, being espe-
cially accumulated in the intervals iDetween the sacculi ; in the rectam they form
a thick layer, especially at its lower end, where they become numerous, and form
the Internal sphincter.
782
ORGANS OF DIGESTION.
The cellular coat connects the muscular and mucous layers closely together.
The mucous memhrayie^ in the caecum and colon, is pale, and of a grayish or
pale yellow color. It is quite smooth, destitute of villi, and raised into nume-
rous crescentic folds, which correspond to the intervals between the sacculi.
In the rectum it is thicker, of a darker color, more vascular, and connected
loosely to the muscular coat as in the oesophagus. When the lower part of the
rectum is contracted, its mucous membrane is thrown into a number of folds,
some of which, near the anus, are longitudinal in direction, and are effaced by
the distension of the gut. Besides these, there are certain permanent folds, of a
semilunar shape, described by Mr. Houston.^ They are usually three in number ;
sometimes a fourth is found, and, occasionally, only two are present. One is
situated near the commencement of the rectum, on the rigiit side; another ex-
tends inwards from the left side of the tube, opposite the middle of the sacrum ;
the largest and most constant one projects backwards from the fore part of the
rectum, opposite the base of the bladder. When a fourth is present, it is situ-
ated about an inch above the anus on the back of the rectum. These folds are
about half an inch in widtli, and contain some of the circular fibres of the gut.
In the empty state of the intestine they overlap each other, as Mr. Houston
remarks, so effectually as to require considerable manoeuvring to conduct a
bougie or the linger along the canal of the intestine. Their use seems to be, " to
support the weight of fecal matter, and prevent its urging towards the anus,
where its presence always excites a sensation demanding its discharge." The
mucous membrane of the large intestine presents for examination epithelium,
simple follicles, and solitary gTands.
Fifj. 447.— Minute Structure of Larsje IntestiiiPi.
Surface of miicous membrane, 'wiili
opeuing of Lieberkiihn's follicles.
Y Lieberkiihu's follicles.
Muscularis niucosre (two layers).
isubmucous coniieciive tissue.
Solitary C^land.
The epithelium is of the columnar kind.
The simple follicles are minute tubular prolongations of the mucous membrane,
arranged perpendicularly, side by side, over its entire surface; they are longer,
more numerous, and placed in much closer apjiosition than those of the small
intestine ; and they open by minute rounded orifices upon the surface, giving it
a cribriform appearance.
The solitary (jlands in the largo intestine are most :il)iiiidaiit in ihe cvccnm
?iW(\ appendix verm.iformis ; but are irregularly scattered also over the rest oi'
the intestine. They are similar to those of the small intestine.
' Dill). lIi)H[). Il(>|)orts, vol. V. p. 163.
THE LIVER. 783
The Liver.
The Liver is a glandular organ of large size, intended mainly for the secretion
of the bile, but effecting also important changes in certain constituents of the
blood in their passage through the gland. It is situated in the right hypochon-
driac region, and extends across the epigastrium into the left hypochondrium.
It is the largest gland in the body, weighing from three to four pounds (from
lifty to sixty ounces avoirdupois). It measures, in its transverse diameter,
from ten to twelve inches ; from six to seveu in its an tero- posterior ; and is
about three inches thick at the back part of the right lobe, which is the thickest
part.
Its upper surface is convex, directed upwards and forwards, smooth, covered
by peritoneum. It is in relation with the under surface of the Diaphragm ; and
below, to a small extent, with the abdominal parietes. The surface is divided
into two unequal lobes, the right and left, by a fold of peritoneum, the suspensory
or broad ligament.
Its under surface is concave, directed downwards and backwards, and in rela-
tion with the stonfiach and duodenum, the hepatic flexure of the colon, and the
right kidney and suprarenal capsule. The surface is divided by a longitudinal
fissure into a right and left lobe.
The posterior border is rounded and broad, and connected to the Diaphragm
by the coronary ligament ; it is in relation with the aorta, the vena cava, and
the crura of the Diaphragm.
The anterior border is thin and sharp, and marked, opposite the attachment of
the broad ligament, by a deep notch. In adult males, this border usually corre-
sponds with the margin of the ribs ; but in women and children, it usually pro-
jects below the ribs.
The right extremity of the liver is thick and rounded ; whilst the left is thin
and flattened.
Changes of Position. The student should make himself acquainted with the different circum-
stances under whicli the liver chantyes its position, as they are of importance in determining the
existence of enlargement or other disease of the organ.
Its position varies according to the posture of the body ; in the upright and sitting posture,
it usually recedes behind the ribs. Its position varies, also, with the ascent or descent of the
Diaphragm. In a deep inspiration, the liver descends below the ribs ; in expiration, it is raised
to its ordinary level. Again, in emphysema, where the lungs are distended, and the Diaphragm
descends very low, the liver is pushed down ; in some other diseases, as phthisis, where the dia-
phragm is much arched, the liver rises very high up. Pressure from without, as in tight lacing,
by compressing the lower part of the chest, displaces the liver considerably, its anterior edge
often extending as low as the crest of the ilium ; and its convex surface is often, at the same time.
deeply indented from pressure of the ribs. Again, its position varies greatly, according to the
greater or less distension of the stomach and intestines. When the intestines are empty, the
liver descends in the abdomen ; but when they are distended, it is pushed upwards. Its relations
to surrounding organs may also be changed by the growth of tumors, or by collection of fluid
in the thoracic or abdominal cavities.
Ligaments. The ligaments of the liver (Fig. 448) are five in number: four
being formed of folds of peritoneum ; the fifth, the ligament uon teres., is a round
fibrous cord, resulting from the obliteration of the umbilical vein. The liga-
ments are the longitudinal, two lateral, coronary, and round.
The longitudinal ligament (broad, falciform, or suspensory ligament) is a broad
and thin antero-posterior peritoneal fold, falciform in shape, its base being
directed forwards, its apex backAvards. It is attached by one margin to the
under surface of the Diaphragm, and the posterior surface of the sheath of the
right Rectus muscle as low down as the umbilicus ; by its hepatic margin, it
extends from the notch on the anterior margin of the liver, as far back as its
posterior border. It consists of two layers of peritoneum closely united together.
Its anterior free edge contains the round ligament between its layers.
The lateral ligaments^ two in number, right and left, are triangular in shape.
They are formed of two layers of peritoneum united, and extend from the sides
784
ORGANS OF DIGESTION.
of tlie Diapliragm to tlie adjacent margins of tlie posterior border of the organ.
The left is the longer of the two, and lies in front of the oesophageal opening in
the Diaphragm.
The coronary ligament connects the posterior border of the liver to the
Diaphragm. It is formed by the reflection of the peritonenm with the Dia-
phragm on to the upper and lower margins of the posterior border of the organ.
The coronary ligament consists of two layers, which are continuous on each
Fig. 448. — The Liver. Upper Surface.
side with the lateral ligaments ; and in front, with the longitudinal ligament.
Between the layers, a large oval interspace is left uncovered by peritoneum,
and connected to the Diaphragm by a firm areolar tissue. This space is sub-
divided, near its left extremity, into two parts by a deep notch (sometimes a
canal), whicli lodges the inferior vena cava, and into which open the hepatic
veins.
The round ligament (Fig. 448) is a fibrous cord resulting from the obliteration
of the umbilical vein. It ascends from the umbilicus, in the anterior free margin
of the longitudinal ligament, to the notch in the anterior border of the liver,
from which it may be traced along the longitudinal fissure on the under surfoce
of the liver, as far back as the inferior vena cava.
Fissures (Fig. 449). Five fissures are seen upon the under surface of the
liver, which serve to divide it into five lobes. They are the longitudinal fissure,
the fissure of the ductus venosus, the transverse fissure, the fissure for the gall-
bladder, and the fissure for the vena cava.
The longitudinal fissure is a deep groove, which extends from the notcli on
the anterior margin of the liver to the posterior border of the organ. It sepa-
rates the right and left lobes: the transverse fissure joins it, at right angles,
about one-third from its posterior extremity, and divides it into two parts. The
anterior half is called the urnli Ural fissure \ it is deeper than the posterior part,
and lodges the umbilical vein in the foetus, or its remains (the round ligament)
in the adult. Tlris fissure is often partially bridged over by a prolongation of
the hepatic substance, \]^q pons hepatis.
The fissvre of lite dv.cfvs venosus is the back part of the longitudinal fissure;
it is shorter and shallower than the anterior portion. It lodges in the lailus lhc
ductus venosus, ami in lhc adult a slender (ibrous cord, the obliterated remains
of that vessel.
THE LIVER.
785
The transverse or 'portal fissure is a sliort but deep fissure, about two inciies
in length, extending transversely across the under surface of the right lobe,
nearer to its posterior than its anterior border. It joins, nearly at right angles,
with the longitudinal fissure. By the older anatomists this fissure was con-
sidered the gateway (porta) of the liver ; hence the large vein which enters at
this point was called the portal vein. Besides this vein, the fissure transmits
the hepatic artery and nerves, and the hepatic duct and lymphatics. At their
entrance into the fissure, the hepatic duct lies in front to the right, the hepatic
artery to the left, and the portal vein behind and between (Fig 455).
Fig. 449. — The Liver. Under Surface.
The fissure for the gall-hladder (fossa cystis fellese) is a shallow, oblong fossa,
placed on the under surface of the right lobe, parallel with the longitudinal
fissure. It extends from the anterior free margin of the liver, which is occa-
sionally notched for its reception, to near the right extremity of the transverse
fissure.
The fissure for the vena cava is a short, deep fissure, occasionally a complete
canal, which extends obliquely upwards from a little behind the right extremity
of the transverse fissure to the posterior border of that organ, where it joins the
fissure for the ductus venosus. On slitting open the inferior vena cava which
is contained in it, a deep fossa is seen, at the bottom of which the hepatic veins
communicate with this vessel. This fissure is separated from the transverse
fissure by the lobus caudatus, and from the longitudinal fissure by the lobulus
Spigelii.
Lobes. The lobes of the liver, like the ligaments and fissures, are five in
number: the right lobe, the left lobe, the lobus quadratus, the lobulus Spigelii,
and the lobus caudatus.
The right lobe is much larger than the left ; the proportion between them being
as six to one. It occupies the right liypochondrium, and is separated from the
left lobe, on its upper surface, by the longitudinal ligament; on its under surface,
by the longitudinal fissure ; and in front by a deep notch. It is of a quadri-
lateral form, its under surface being marked by three fissures: the transverse
fissure, the fissure for the gall bladder, and the fissure for the inferior vena cava;
and by two shallow impressions, one in front (impressio colica), for the hepatic
flexure of the colon ; and one behind (impressio renalis)^ for the right kidney
and suprarenal capsule.
The left lobe is smaller and more flattened than the right. It is situated in the
50
786 ORGANS OF DIGESTION.
epigastric and left liypocliondriac regions, sometimes extending as far as tlie
upper border of the spleen. Its upper surface is convex; its under concave
surface rests upon the front of the stomach ; and its posterior border is in rela-
tion with the cardiac orifice of the stomach.
The lolms quadra tus, or square lobe, is situated on the under surface of the
right lobe, bounded in front by the free surface of the liver ; behind, by the
transverse fissure; on the right, by the fissure for the gall-bladder; and, on the
left, by the umbilical fissure.
The lohulus Spiyelii projects from the back part of the under surface of the
right lobe. It is bounded, in front, by the transverse fissure ; on the right, by
the fissure for the vena cava ; and, on the left, by the fissure for the ductus
venosus.
The lolms caudatus^ or tailed lobe, is a small elevation of the hepatic substance,
extending obliquely outwards, from the base of the lobulus Spigelii, to the under
surface of the right lobe. It separates the right extremity of the transverse
fissure from the commencement of the fissure for the inferior cava.
Vessels. The vessels connected with the liver are also five in number: they
are the hepatic artery, the portal vein, the hepatic vein, the hepatic duct, and
the lymphatics.
The hepatic artery^ portal vein, and hepatic duct^ accompanied by numerous
lymphatics and nerves, ascend to the transverse fissure, between the layers of
the gastro-hepatic omentum; the hepatic duct lying to the right, the hepatic
artery to the left, and the portal vein behind the other two. They are enveloped
in a loose areolar tissue, the capsule of Glisson, which accompanies the vessels
in their course through the portal canals, in the anterior of the organ.
The hepatic veins convey the blood from the liver. They commence at the
circumference of the organ, and proceed towards the deep fossa in its posterior
border, where they terminate, by two large and several smaller branches, in the
inferior vena cava.
The hepatic veins have no cellular investment; consequently, their parietes
are adherent to the walls of the canals through which they run; so that, on a
section of the organ, these veins remain widely open and solitary, and may be
easily distinguished from the branches of the portal vein, which are more or
less collapsed, and always accompanied by an artery and duct.
The ly^npjhatics are large and numerous, consisting of a deep and superficial
set. They have been already described,
Neeves. The nerves of the liver are derived from the hepatic plexus of the
sympathetic, from the pneumogastric nerves, especially the left, and from the
right phrenic.
Structure. The substance of the liver is composed of lobules, held together
by an extremely fine areolar tissue, and of the ramifications of the portal vein,
hepatic duct, hepatic artery, hepatic veins, lymphatics, and nerves; the whole
being invested by a fibrous and a serous coat.
The serous coat is derived from the peritoneum, and invests the entire surface
of the organ, excepting at the attachment of its various ligaments, and at the
bottom of the different fissures, where it is deficient. It is intimately adherent
to tlie fibrous coat.
The fihrov.s coat lies beneath the serous investment, and covers the entire
surface of the organ. It is difficult of demonstration, excepting where the
serous coat is deficient. At the transverse fissure, it is continuous with the
capsule of Glisson ; and, on the surface of the organ, with the areolar tissue
separating the lobules.
Tlie lolniles form the chief mass of the licyxatic substance; they may be scon
either on the surface of the organ, or by making a section through the gland.
They are small granular bodies, about the size of a millet-seed, measuring from
one-twentieth to one-ton lh of an inch in diameter. If divided longitudinally,
they have a foliated, and, iC transversely, a polygonal, outline. The bases of the
STRUCTURE OF THE LIVER.
787
Fig. 450.
B
H. Longitudinal sectioa of an liepatic vein.
a, Portioa o-f the canal, from, ■which the yein
has been removed ; b, orifices of ultimate twigs
of the vein (sublobular), situated in the centre
of the lobules. After Kiernan.
lobules are clustered round tlie smallest brandies (sublobular) of the bepatic
veins, to which each is connected bj means of a small branch, which issues
from the centre of the lobule (intralobular).
The remaining part of the surface of each
lobule is imperfectly isolated from the sur-
rounding lobules, by a thin stratum of areolar
tissue, and by the smaller vessels and ducts.
If one of the hepatic veins be laid open,
the bases of the lobules may be seen through
the thin wall of the vein, on which they rest,
arranged in the form of a tessellated pave-
ment, the centre of each polygonal space pre-
senting a minute aperture, the mouth of a
sublobular vein.
Each lobule is composed of a mass of cells ;
of a plexus of biliary ducts; of a venous
plexus, formed by branches of the portal vein ;
of a radicle of an hepatic vein (intralobular);
of minute arteries; and probably, of nerves
and lymphatics.
The hepatic cells form the chief mass of
the substance of a lobule, and lie' in the inter-
spaces of the capillary plexus, being probably
contained in a tubular network, which accord-
ing to some authors forms the origin of the
biliary ducts.
The portal vein carries the blood to the
liver, from which the bile is 'secreted; the
hepatic vein carries the superfluous blood
from the liver, and the bile duct carries the
blip secreted by the hepatic cells.
The course of the circulation in the liver is
best traced in the natural direction, viz., from
the vena portae to the hepatic vein, which is a
branch of the vena cava. The portal vein
(Fig. 4z51) gives off small branches, which, as
they ramify between the lobules of the liver,
are called the mterlobular veins, and form a
plexus surrounding the lobules. Branches
from this plexus enter the substance of the
lobule, forming a capillary network inside it,
the m^ralobular capillary plexus. These
veins unite into one which issues from the
lobule, the m^ralobular vein, forming as it
were the stalk or axis of the lobule. The
intralobular veins run into small branches —
sM/:'lobular — around which therefore the lobules
are clustered, and which are the radicles of the
hepatic veins. These veins (as mentioned at
p. 584) finally converge to form three large
trunks which open into the vena cava, while
that vessel is situated in the fissure appro-
priated to it at the back of the liver.
The hepatic cells are of a more or less sphe-
roidal form ; but may be rounded, flattened,
or many-sided, from mutual compression. They vary in size from the
Longitudinal section of a small portal vein
and canal, after Kiernan. a. Portions of the
canal from which the vein has been removed;
h, side of the portal vein in contact with the
canal ; c, the side of the vein which is separated
from the canal by the hepatic artery and duct,
with areolar tissue (Glisson's capsule) ; (J, inter-
nal surface of the portal vein, through which
are seen the outlines of the lobules and the
openings (e) of the interlobular veins ; /, vagi-
nal veins of Kiernan • g, hepatic artery ; h,
hepatic duct.
the
1
3'OOTJ
1 T*0 0
to
of an inch in diameter, and contain a distinct nucleus in the interior, or
788 ORGANS OF DIGESTION.
sometimes two. In tlie nucleus is a iiiglilj refracting nucleolus, with granules.
The cell-contents are viscid, and contain yellow particles, the coloring matter of
the bile, and oil-globules. The cells adhere together by the surfaces, so as to
form rows, which radiate from the centre towards the circumference of the
lobule. These cells are the chief agents in the secretion of the bile.
Fiff. 452.
Horizontal section of liver (dog). The vena port* has been injected, a. Trunk of interlobular vein.
i>, Trunk of interlobular vein. A dense system of capillary vessels is between them.
Origin of the hiliary ducts. Three views have prevailed in recent times as to
the origin of the biliary ducts. 1. That they commence external to the lobules'
in an m!;erlobular plexus, the bile being secreted by the hepatic cells within the
lobule, and passing into the radicles of the ducts by osmosis from those cells.
This was Kiernan's view.* 2. The other two views coincide in the belief that
the radicles of the biliary ducts commence within the lobules by a plexus of
m;;ralobular channels, but they differ as to the relation between these channels
and the hepatic cells: the one, which we will call Beale's view, teaches that
the hepatic cells are contained within the intralobular biliary channels ; 3. The
other view, which we may call Hering's, teaches that the intralobular biliary
channels lie between the hepatic cells. This anatomist has given what appears
the most intelligible description of the minute finatomy of the liver, and one
which really coincides in many essential points with the original description of
Kiernan, as well as with that of Beale. Hering describes the liver cells as lying
packed together in the channels which are formed between the meshes of the
capillary bloodvessels, but separated from the wall of the capillary by a clear
space. In the centre of the line which forms the base of a pair of cells (or
more rarely in the human subject in the angle formed by the meeting of several
cells) a minute channel is formed, which is the radicle of the bile duct, the
intralobular biliary channel, much smaller than the capillary or the hepatic
cells. Kiernan's view would confine the name of biliary ducts to the bile
passages external to the lobule (intralobular), while Beale's view would regard
the whole intercapinary channel, bile cells and all, as an intralobular biliary
passage. Hering's view is in most respects the same as Chrzonszczcwsky's,
who first succeeded in demonstrating these intralobular (or intercellular) bihary
passages by a kind of auto-injection in living animals — i. e., by injecting coloring
' Kiprnnn, howovor, aditiiftod Hint pntsil)ly tlio biliury clminiols iiiin;lit bo tracod somo short
(listnnce into the lobules, whilst others (Honle, etc.) believed that lliey ()rii;:iiiiitc entirely e.\teriial
to the lobules.
GALL-BLADDER.
789
matter into the blood of tlie living animal,
found in the bile-ducts. The ducts form a
lobules; and the interlobular branches unite
and form vaginal branches, which lie in the
portal canals, with branches of the portal vein
and hepatic duct. The ducts finally form
two large trunks, which leave the liver at
the transverse fissure, and the union of these
is the hepatic dnct.
The Portal veiri, on entering the liver at
the transverse fissure, divides into primary
branches, which are contained in the portal
canals, together with branches of the hepatic
artery and duct, and the nerves and lym-
phatics. In the larger portal canals, the
vessels are separated from the parietes, and
joined to each other, by a loose cellular web,
the capsule of Grlisson. The veins, as they
lie in the portal canals, give ofi' vaginal
branches, which form a plexns (vaginal
plexus) in Glisson's capsule. From this
plexus, and from the portal vein itself, the
interlobular veins are given off.
The Hepatic artery appears destined chiefly
for the nutrition of the coats of the large
■ vessels, the ducts, and the investing mem-
branes of the liver. It enters the liver at
the transverse fissure, with the portal vein
and hepatic duct, and ramifies with these
vessels through the portal canals. It gives
off vaginal branches, which ramify in the
capsule of Glisson; and other branches, which
are distributed to the coats of the vena porta?
and hepatic duct. From the vaginal plexus,
interlobular branches are given off, which
ramify through the interlobular fissures, a
few branches being distributed to the lobules.
Kiernan supposes that the branches of the
hepatic artery terminate in a capillary plexus,
which communicates with the branches of
the vena portae.
The Hepatic veins commence in the interior
of each lobule by a plexus, the branches of
which converge to form the intralobular vein.
The intralobular vein passes through the
centre of the lobule, and leaves it at its base
to terminate in a sublobular vein.
The sublobular veins unite with neighboring
branches to form larger veins ; and these
join to form the large hepatic trunks, which
terminate in the vena cava.
when the coloring matter may be
plexus (interlobular) between the
Microscopical section from the liver of a child
three months old, hardened in chromic acid. The
hepatic cells (b), with their single nuclei, are
separated from the capillary wall hy a small inter-
vening space. The caplUarios (a) contain closely
compressed colored, and a few colorless, blood
corpuscles. A few elongated nuclei belonging to
the capillary wall are seen. Within the line of
junction (septum), between two hepatic cells, the
transverse section of a biliary duct is seen as a
small transparent space (c). There is also one at
the angle, where several of these cells come into
contact (d).
Fiff. 4.54.
A transverse section of a small portal canal and
its vessels, after Kiernan. 1, Portal vein; 2, In-
terlobular branches ; 3, branches of the vein
termed, l?y Mr. Kiernan, vaginal, also giving off
interlobular branches ; 4, hepatic duct ; 3, hepatic
artery.
Gall-Bladder.
The Gall-bladder is the reservoir for the bile; it is a conical or pear-shaped
membranous sac, lodged in a fossa on the under surface of the right lobe of the
liver, and extending from near the right extremity of the transverse fissure to
790 ORGANS OF DIGESTION.
the anterior free margin of tlie organ. It is about four inches in length, one
inch in breadth at its widest part, and holds from eight to ten drachms. It is
divided into a fundus, body, and neck. The fundus^ or broad extremity, is
directed downwards, forwards, and to the right, and occasionally projects from
the anterior border of the liver; the }>ody and neck are directed upwards and
backwards to the left. The gall-bladder is held in its position by the peritoneum,
which, in the majority of cases, passes over its under surface, but the serous
membrane occasionally invests the gall-bladder, which then is connected to the
liver by a kind of mesentery.
Relations. The body of the gall-bladder is in relation, by its upper surface,
with the liver, to which it is connected by areolar tissue and vessels ; by its
under surface, with the first portion of the duodenum, occasionally the pyloric
end of the stomach, and the hepatic flexure of the colon. The fundus is com-
pletely invested by peritoneum; it is in relation, in front, with the abdominal
parietes, immediately below the tenth costal cartilage; behind, with the trans-
verse arch of the colon. The neck is narrow, and curves upon itself like the
italic letter /; at its point of connection with the body and with the cystic duct,
it presents a well-marked constriction.
When the gall-bladder is distended with bile or calculi, the fundus may be felt through the
abdominal parietes, especially in an emaciated subject: the relations of this sac will also serve to
explain the occasional occurrence of abdominal biliary fistulae, through which biliary calculi may
pass out, and of the passage of calculi from the gall-bladder into the stomach, duodenum, or colon,
■which occasionally happens.
Structure. The gall-bladder consists of three coats : serous, fibrous and mus-
cular, and mucous.
The external or serous coat is derived from the peritoneum; it completely
invests the fundus, but covers the body and neck only on their under surface.
The middle or fibrous coat is a thin but strong fibrous layer, which forms the
framework of the sac, consisting of dense fibres which interlace in all directions.
Plain muscular fibres are also found in this coat, disposed chiefly in a longi-
tudinal direction, a few running transversely.
The internal or mzicous coat is loosely connected with the fibrous layer. It is
generally tinged with a yellowish-brown color,, and is everywhere elevated into
minute rugas, by the union of which numerous meshes are formed; the depressed
intervening spaces having a polygonal outline. The meshes are smaller at the
fundus and neck, being most developed about the centre of the sac. Opposite
the neck of the gall-bladder, the mucous membrane j)rojects inwards so as to
form a large valvular fold.
The mucous membrane is covered with columnar epithelium, and secretes an
abundance of thick viscid mucus ; it is continuous through the hepatic duct
with the mucous membrane lining the ducts of the liver, and through the ductus
communis choledochus with the mucous membrane of the alimentary canal.
The Biliary Ducts are, the hepatic, the cystic, and the ductus communis
choledochus.
The hepatic duct is formed of two trunks of nearly equal size, wdiich issue
from the liver at the transverse fissure, one from the right, the other from the
left lobe ; these unite, and pass downwards and to the right for about an inch
and a half, to join at an acute angle with the cystic duet, and so form the
ductus communis choledochus.
^\ie cystic duct, the smallest of the three 1)iliary ducts, is about an inch in
length. It passes obliquely downwards and to the left from tlic neck of the
gall-loladder, and joins the hepatic duct to form the common d\\r\. It lies in
the gastro-hcjjalic omentum, in front of the vena cava, the cystic aiiery lying to
its left side. The mucous membrane lining its interior is thrown into a series
of crcscentic folds, from five to twelve in number, which project into the duct in
regular succession, and arc directed obliquely round the tube, presenting much
the appearance of a continuous spiral valve. They exist only in the human
PANCREAS.
791
subject. When tlie duct lias been distended, the interspaces between the folds
are' dilated, so as to give to its exterior a sacculated appearance.
The ductus communis choledochus^ the largest of the three, is the common ex-
cretory duct of the liver and gall-bladder. It is about three inches in length,
of the diameter of a goose-quiil, and formed by the junction of the cystic and
hepatic ducts. It descends along the right border of the lesser omentum, behind
Fi"-. 455.— The Parts in the Gastro-hepatic Omentum, its anterior Layer being removed.
the first portion of the duodenum, in front of the ven^e portse, and to the right
of the hepatic artery ; it then passes between the pancreas and descending por-
tion of the duodenum, and, running for a short distance along the right side of
the pancreatic duct, near its termination, passes with it obliquely between the
mucous and muscular coats, the two opening by the common orifice upon the
summit of a papilla, situated at the inner side of the descending portion of the
duodenum, a little below its middle.
Structure. The coats of the biliary ducts are, an external or fibrous, and an
internal or mucous. The fibrous coat is composed of a strong areolar fibrous
tissue. The mucous coat is continuous with the lining membrane of the hepatic
ducts and gall-bladder, and also with that of the duodenum. It is provided
with numerous glands, the orifices of which are scattered irregularly in the
larger ducts, but in the smaller hepatic ducts are disposed in two longitudinal
rows, one on each side of the vessel. These glands are of two kinds. Some are
ramified tubes, which occasionally anastomose, and from the sides of which saccu-
lar dilatations are given off; others are small clustered cellular glands, which open
either separately into the hepatic duct, or into the ducts of the tubular glands.
The Pancreas.
Diasedion. The pancreas may be exposed for dissection in three different ways : 1. By raising
the liver, drawing down the stomach, and tearing through the gastro-hepatic omentum and the
ascending layer of the tra,nsverse meso-colon. 2. ]3y raising the stomach, the arch of the colon, and
great omentum, and then dividing the inferior layer of the transverse meso-colon. 3. By dividing
the two laj-ers of peritoneum, which descend from the great curvature of the stomach to form tho
great omentum; turning the stomach upwards, and then cutting through the ascending layer of
the transverse meso-colon. (See Fig. 433, p. 764).
792
ORGANS OF DIGESTION.
The Pancreas (rtai-xtiiaj, all flesh) is a conglomerate gland, analogous in its
structure to the salivary glands. In shape it is transversely oblong, flattened
from before backwards, and bears some resemblance to a dog's tongue, its right
extremity being broad, and presenting a sort of angular bend from above down-
wards, called the head, whilst its left extremity gradually tapers to form the tail,
the intermediate portion being called the body. It is situated transversely across
the posterior wall of the abdomen, at the back of the epigastric and both hypo-
chondriac regions. Its length varies from six to eight inches, its breadth is an
inch and a half, and its thickness from half an inch to an inch, being greater at
its right extremity and along its upper border. Its weight varies from two to
three and a half ounces, but it may reach six ounces.
The right extremity or head of the pancreas (Fig. 456) is curved upon itself
from above downwards, and is embraced by the concavity of the duodenum.
The Pancreas and its Relations.
The common bile-duct descends behind, between the duodenum and pancreas;
and the pancreatico-duodenal artery descends in front between the same parts.
On the posterior aspect of the pancreas is a lobular fold of the gland, which
passes transversely to the left, behind the superior mesenteric vessels, forming
the back part of the canal in which they are contained. It is sometimes detached
from the rest of the gland, and is called the lesser pancreas.
The lesser end or tail of the pancreas is narrow ; it extends to the left as far as
the spleen, and is placed over the left kidney and suprarenal capsule.
The hody of the pancreas is convex in front, and covered by the ascending
layer of the transverse meso-colon and the posterior surface of the stomach.
The posterior surface is concave, and has the following structures interposed
between it and the first lumbar vertebra : the superior mesenteric artery and
vein, the commencement of the vena portse, the vena cava, the aorta, the left
kidney, the suprarenal capsule, and the corresponding renal vessels.
The vpper horder is thick, and has resting upon it, near its centre, the poehac
axis; the splenic artery and vein arc lodged in a deep groove or canal in this
border; and to the right, the first part of ihc duodenuni nnd ihe hepatic artery
arc in relation with it.
The lower border, thinner than the upper, is separated from the transverse
SPLEEN. 793
portion of the duodenum by the superior mesenteric artery and vein : to the
left of these the inferior mesenterio vein ascends behind the pancreas to join the
splenic vein.
The pancreatic duct, called the canal of Wirsung from its discoverer, extends
transversely from left to right through the substance of the pancreas, nearer to
its lower than its upper border, and lying nearer its anterior than its posterior
surface. In order to expose it, the superficial portion of the gland must be
removed. Traced backwards, it is found to commence by an orifice common to
it and the ductus communis choledochus, upon the summit of an elevated papilla,
situated at the inner side of the descending portion of the duodenum, a little
below its middle : from ^his papilla it passes very obliquely through the mucous
and muscular coats, separates itself from the ductus communis choledochus, and,
ascending slightly, runs from right to left through the middle of the gland,
giving off numerous branches, which commence in its lobules.
Sometimes the pancreatic duct and ductus communis choledochus open sepa-
rately into the duodenum. The excretory duct of the lesser pancreas is called
the ductus pancreaticus minor ; it opens into the main duct near the duodenum,
and sometimes separately into that intestine, at a distance of an inch or more
from the termination of the principal duct.
The pancreatic duct, near the duodenum, is about the size of an ordinary
quill ; its walls are thin, consisting of two coats, an external fibrous and an in-
ternal mucous ; the latter is thin, smooth, and furnished, near its termination,
with a few scattered follicles.
Sometimes the pancreatic duct is double, up to its point of entrance into the
duodenum.
In structure, the pancreas closely resembles the salivary glands ; but it is
looser and softer in its texture. The fluid secreted by it is almost identical with
saliva.
Vessels qnd Nerves. The arteries of the pancreas are derived from the splenic,
the pancreatico-duodenal branch of the hepatic, and the superior mesenteric.
Its veins open into the splenic and superior mesenteric veins. Its lymphatics
terminate in the lumbar glands. Its nerves are filaments from the splenic
plexus.
The Spleen.
The Spleen is usually classified, together with the thyroid, thymus, and
suprarenal capsules, as one of the ductless, or blood glands. It possesses no
excretory duct. It is of an oblong flattened form, soft, of very brittle consist-
ence, highly vascular, of a dark bluish-red color, and situated in the left hypo-
chondriac region, embracing the cardiac end of the stomach. It is invested by
peritoneum, and connected with the stomach by the gastro-splenic omentum.
Relation. The external surface is convex, smooth, and in relation with the
under surface of the Diaphragm, which separates it from the ninth, tenth, and
eleventh ribs of the left side. The internal surface is slightly concave, and
" divided by a vertical fissure, the Mlum, into an anterior or larger, and a poste-
rior or smaller portion. The hilum is pierced by several irregular apertures,
for the entrance and exit of vessels and nerves. At the margins of the hilum,
the two layers of peritoneum are reflected from the surface of the spleen on to
the cardiac end of the stomach, forming the gastro-splenic omentum, which con-
tains between its layers the splenic vessels and nerves, and the vasa brevia.
The internal surface is in relation, in front, with the great end of the stomach ;
below, with the tail of the pancreas ; and behind, with the left crus of the Dia-
phragm, and corresponding suprarenal capsule. The upper end, thick and
rounded, is in relation with the Diaphragm, to which it is connected by a fold
of peritoneum, the suspensory ligament. The loiuer end is pointed ; it is in
relation with the left extremity of the transverse arch of the colon. The
794
ORGANS OF DIGESTION.
anterior margin is free, rounded, and often notched, especially below. The
posterior margin is rounded, and lies in relation with the left kidney, to which
it is connected by loose areolar tissue.
The spleen is held in its position by two folds of peritoneum : one, the gastro-
splenic omentum^ connects it with the stomach ; and the other, the suspensory
ligament^ with the under surface of the Diaphragm.
Fig. 457. — Ti'ansverse Section of the Spleen, showing the Trabecular Tissue
and the Splenic Vein and its Branches.
The size and weight of the spleen are liable to very extreme variations at
different periods of life, in different individuals, and in the same individual under
different conditions. In the adult^ in whom it attains its greatest size, it is
usually above five inches in length, three or four inches in breadth, and an inch,
or an inch and a half in thickness, and weighs about seven ounces. At hirth, its
weight, in proportion to the entire body, is almost equal to what is observed in
the adult, being as 1 to 850 ; whilst in the adult it varies from 1 to 320 and
400. In old age^ the organ not only decreases in weight, but decreases con-
siderably in proportion to the entire body, being as 1 to 700. The size of the
spleen is increased during and after digestion, and varies considerably according
to the state of nutrition of the body, being large in highl^^-fed, and small in
starved animals. In intermittent and other fevers it becomes much enlarged,
weighing occasionally from 18 to 20 pounds.
Structure. The spleen is invested by two coats : an external serous, and an
internal fibrous elastic coat.
The external^ or serous coat^ is derived from the peritoneum ; it is thin, smooth,
and in the human subject intimately adherent to the fibrous elastic coat. It-
invcsts almost the entire organ ; being reflected from it, at the hilum, on to
the great end of the stomach, and at the upper end of the organ on to the Dia-
phragm.
The fibrous elastic coat forms the framework of the spleen. It invests the
exterior of the organ, and at the hilum is reflected inwards upon the vessels in
tlie form of vaginas or sheaths. From these slicaths, as well as from the inner
surface of the fibro-elastic coat, numerous small fibrous bands, trahecnhv (Fig.
457), arc given offin all directions; these uniting, constitute the areolar frame-
work of the spleen. The proper coat, the sheaths of the vessels and the Ira-
beculse, consist of a dense mesh of white and yellow elastic fibrous tissues, the
STEUCTURE OF THE SPLEEN. 795
latter considerably predominating. It is owing to the presence of this tissue,
that the spleen possesses a considerable amount of elasticity, to allow of the
very considerable variations in size that it presents under certain circumstances.
In some of the mammalia, in addition to the usual constituents of this tunic,
there are found numerous pale, flattened, spindle-shaped, nucleated fibres, like
unstriped muscular fibres. It is probably owing to this structure, that the
spleen possesses, when acted upon by the galvanic current, faint traces of con-
tractility.
The proper substance of the spleen or spleen pulp is inclosed in the meshes of
a fine areolar tissue, composed of branching corpuscles similar to those of the
common connective tissue. The spaces formed by the processes of these cells
inclose the proper elements of the pulp, which are now to be described, and the
radicles of the veins are continuous with those spaces, their walls being pro-
longed into the processes of the cells. The pulp is a soft mass of a dark reddish-
brown color, consisting of colorless and colored elements.
Fig. 458.— The Malpighiau Corpuscles, and their Relation with the Splenic Artery
and its' Branches.
The colorless elements consist of granular matter; nuclei, about the size of the
red blood-disks, homogeneous or granular in structure ; and nucleated vesicles
in small numbers. These elements form, probably, one-half or two-thirds of the
whole substance of the pulp, filling up the interspaces formed by the partitions
of the spleen, and lying in close contact with the walls of the capillary vessels,
so as to be readily acted upon by the nutrient fluid which permeates them.
Thus in well-nourished animals, they form a large part of the entire bulk of the
spleen, whilst they diminish in number, and occasionally are wanting, in starved
animals. The application of chemical tests shows that they are essentially a
proteine compound.
The colored elements of the pulp consist of red blood-globules and of colored
corpuscles, either free, or included in cells. Sometimes, unchanged blood-disks
are seen included in a cell; but more frequently the included blood-disks are
altered both in form and color. Besides these, numerous deep-red, or reddish-
yellow, or black corpuscles and crystals, either single or aggregated in masses,
796
ORGANS OF DIGESTION.
are seen diffused tlirougliout the pulp-substance : tliese, in cliemical composition,
are closely allied to the lieejnatin of the blood.
Malpighian Corpuscles. On examining the cut surface of a healthy spleen, a
number of small semi-opaque bodies, of gelatinous consistence, are seen dissemi-
nated throughout its substance; these are the splenic or Malpighian corpuscles
(Fig. 458). They may be seen at all periods of life ; but they are more distinct
in early than in adult life or old age ; and they are much smaller in man than
in most mammalia. They are of a spherical or ovoid form, vary considerably
in size and number, and are of a semi-opaque whitisb color. They are appended
to the sheaths of the smaller arteries and their branches, presenting a resem-
blance to the buds of the moss rose. Each consists of a membranous capsule,
Fig. 459.— One of the Splenic Corpuscles, showing its Kelations with the Bloodvessels.
composed of fine pale fibres, which interlace in all directions. In man, the cap-
sule is homogeneous in structure, and formed by a prolongation from the
sheaths of the small arteries to which the corpuscles are attached. The blood-
vessels ramifying on the surface of the corpuscles, consist of the larger ramifica-
tions of the arteries to which the sacculus is connected ; and also of a delicate
capillary plexus, similar to that surrounding the vesicles of other glands. These
vesicles have also a close relation with the veins (Fig. 459). The latter vessels,
which are of considerable size even at their origin, commence on the surface of
each vesicle throughout the whole of its circumference, forming a dense mesh
of veins, in which the Malpighian corpuscle is inclosed. It is probable, that
Worn the blood contained in the capillary network, the material is separated
which is occasionally stored up in the cavity of the corpuscle ; the veins being
so placed as to carry off' under certain conditions, those contents to be discharged
again into the circulation. Each capsule contains a soft, white, semi-fluid sub-
stance, consisting of granular matter, nuclei similar to those found in the pulp,
and a few nucleated cells, the composition of which is apparently albuminous.
These bodies arc very large after digestion is completed, in well-fed animals, and
especially in those fed upon albuminous diet. In starved animals, they disap-
pear altogether.
STRUCTURE OF THE SPLEEN.
797
Tlie minute arteries and veins are inclosed in a slieath derived from tlie capsule
of the spleen, and containing, according to some anatomists, unstriped muscular
fibres. The layers of this sheath (consisting of white fibrous and elastic tissue)
are permeated by lymphoid corpuscles. This lymphoid tissue gives rise to the
Malpighian bodies, which are indeed mere localised expansions of the lymphoid
sheaths of the arteries in places where the meshes of the network are wider.^
The sheaths of the veins are derived from the capsule, which forms an elastic
tube (containing muscular fibres, according to some authors) around the proper
walls of the vessels. W. Miiller describes processes from the trabeculee which
pass into the sheaths of the veins, and serve to keep them open somewhat as the
cerebral sinuses are kept patent by the dura mater.
The splenic artery is remarkable for its large size, in proportion to the size
of the organ; and also for its tortuous course. It divides into from four to six
branches, which enter the hilura of the organ and ramify throughout its sub-
stance (Fig. 460), receiving sheaths from an involution of the external fibrous
Fig. 460. — Transverse Section of the Human Spleen, showing the Distribution of the
Splenic Artery and its Branches.
tunic, the same sheaths also investing the nerves and veins. Each branch runs
in the transverse axis of the organ, from within outwards, diminishing in size
during its transit, and giving off, in its passage, smaller branches, some of which
pass to the anterior, others to the posterior part ; these ultimately terminate in
the proper substance of the spleen, in small tufts or pencils of capillary vessels,
which lie in direct contact with the pulp. Each of the larger branches of the
arteries supplies chiefly that region of the organ in which the bi'anch ramifies,
having no anastomosis with the majority of the other branches.
The capillaries^ supported by the minute trabeculge, traverse the pulp in all
directions, and terminate either directly in the veins, or open into lacunar spaces,
from which the veins originate.
The veins are of large size, as compared with the size of the organ; and their
distribution is limited, like that of the arteries, to the supply of a particular part
of the gland; they are much larger and more numerous than the arteries. They
originate, 1st, as continuations of the capillaries of the arteries ; 2d, by inter-
cellular spaces communicating with each other in the pulp ; 3d, by distinct csecal
pouches. By their junction they form four to six branches, which emerge from
' "The parenchyma of the Malpighian bodies is formed of cells and a retiform intermediate
substance ; the cells agree in their characters with the lymph-corpnscles of the sevpral animals,
and they are constantly found in various stages of development." — W. Muller, in Striclier's
" Handbook."
798 ORGANS OF DIGESTION.
the liilum ; and tliese uniting, form the splenic vein, the largest branch of the
vena portge.
The veins are remarkable for their numerous anastomoses, while the arteries
hardly anastomose at all.
The lymphatics originate in two ways, i. e., from the sheaths of the arteries
and in the trabeculse. The former accompany the bloodvessels, the latter pass
to the superficial lymphatic plexus which may be seen on the surface of the
organ. The two sets communicate in the interior of the organ. They pass
'through the lymphatic glands at the hilum, and terminate in the thoracic duct.
The nerves are derived from branches of the right and left semilunar ganglia,
and right pneumogastric nerve.
The Thorax.
The Tliorax is a conical framework, formed partly of bones, and partly of
the soft tissues by which, they are connected together. It is supported and its
back part is formed by the middle, or dorsal, region of the spine. It is narrow
above, broad below, flattened before and behind, and somewhat cordiform on a
transverse section.
Boundaries. The thorax is bounded in front by the sternum, the six upper
costal cartilages, the ribs, and intercostal muscles ; at the sides, by the ribs and
intercostal muscles : and behind, by the same structures and the dorsal portion
of the vertebral column.
The superior openincj of the thorax is bounded on each side by the first rib ;
in front, by the upper border of the sternum ; and behind, by the first dorsal
vertebra. It is broader from side to side than from before backwards ; and its
direction is backwards and upwards.
The loioer opening^ or Z/ase, is bounded in front by the ensiform cartilage :
behind, by the last dorsal vertebra ; and on each side by the last rib, the Diaphragm
filling in the intervening space. Its direction is obliquely downwards and back-
wards; so that the cavity of the thorax is much deeper on the posterior than
on the anterior wall. It is wider transversely than from before backwards.
Its outer surface is convex ; but it is more flattened at the centre than at the
sides. Its floor is higher on the right than on the left side, corresponding in
the dead body to the upper border of the fifth costal cartilage on the right side ;
and to the corresponding part of the sixth cartilage on the left side.
The parts which pass through the upper opening of the thorax are, from
before backwards, the Sterno-hyoid and Sterno-thyroid muscles, the remains of
the thymus gland, the trachea, oesophagus, thoracic duct, and the longus colli
muscles of each side ; on the sides, the arteria innominata, the left common
carotid and left subclavian arteries, the internal mammary and superior inter-
costal arteries, the right and left venae innominatge, and the inferior thyroid
veins, the pneumogastric, sympathetic, phrenic, and cardiac nerves, the anterior
branch of the first dorsal nerve, and the recurrent laryngeal nerve of the left
side. The apex of each lung, covered by the pleura, also projects through this
aperture, a little above the margin of the first rib.
The viscera contained in the thorax are, the heart, inclosed in its membra-
nous bag, the pericardium ; and the lungs, invested by the pleuras.
The Peeicaedium.
The Pericardium is a conical membranous sac, in which the heart and the
commencement of the great vessels are contained. It is placed behind the
sternum, and the cartilages of the third, fourth, fifth, sixth, and seventh ribs of
the left side, in the interval between the pleurae.
Its apex is directed upwards, and surrounds the great vessels about two inches
above their origin from the base of the heart. Its hase is attached to the central
tendon of the Diaphragm, extending a little further to the left than the right
side. In front it is separated from the sternum by the remains of the thymus
gland above, and a little loose areolar tissue below ; and is covered by the
margins of the lungs, especially the left. Behind^ it rests upon the bronchi, the
oesophagus, and the descending aorta. Laterally, it is covered by the pleura;
(799)
800
THE THOEAX.
tlie phrenic vessels and nerve descending between the two membranes on either
side.
Tlie pericardium is a fibro-serous membrane, and consists, therefore, of two
layers : an external fibrous, and an internal serous.
The fibrous layer is a strong, dense membrane. Above, it surrounds the great
vessels arising from the base of the heart, on which it is continued in the form
of tubular prolongations, which are gradually lost upon their external coat ; the
strongest being that which incloses the aorta. The pericardium may be traced,
over these vessels, to become continuous with the deep layer of the cervical
fascia. Below, it is attached to the central tendon of the Diaphragm ; and, on
. the left side, to its muscular fibres.
The vessels receiving fibrous prolongations from this membrane are the aorta,
the superior vena cava, and the pulmonary arteries and veins. As the inferior
Fig 461. — Front View of tlie Thorax. The Ribs and Sternum are represented
in Relation to the Lungs, Heart, and other Internal Organs.
vena cava enters the pericardium, llimngh the ccnlrnl tendon of llic Diaplirngm,
it receives no covering from the fibrous layer.
The sf'.rous layer invests the heart, and is then reflected on the inner surface
of the pericardium. It consists, therefore, of a visceral and a parietal portion.
The former invests the surface of the heart, and tlie commencement of the great
vessels, to the extent of two inches from their origin ; from these, it is reflected
upon the inner surface of the iibrt^us liiyrr, lining, below, ihc upper surface of
THE HEART. 801
the central tendon of tlie Diaphragm. The serous membrane incloses the aorta
and pulmonary artery in a single tube ; but it only partially covers the superior
and inferior vena cava and the four pulmonary veins. Its inner surface is
smooth and glistening, and secretes a thin fluid, which serves to facilitate the
movements of the heart.
The arteries of the pericardium are derived from the internal mammary, the
bronchial, the oesophageal, and the phrenic.
The Heaet.
The Heart is a hollow muscular organ of a conical form, placed between the
lungs, and inclosed in the cavity of the pericardium.
Position. The heart is placed obliquely in the chest : the broad attached end,
or base, is directed upwards and backwards to the right, and corresponds to the
interval between the fifth and eighth dorsal vertebrae : the apex is directed for-
wards and to the left, and corresponds to the interspace between the cartilage
of the fifth and sixth ribs, one inch to the inner side, and two inches below the
left nipple. The heart is placed behind the lower two-thirds of the sternum,
and projects further into the left than into the right cavity of the chest, extend-
ing from the median line about three inches in the former direction, and only
one and a half in the latter. Its upper border would correspond to a line drawn
across the sternum, on a level with the upper border of the third costal cartilages ;
and its lower border, to a line drawn across the lower end of the gladiolus, from
the costo-xiphoid articulation of the right side, to the point above mentioned,
as the situation of the apex. The lungs cover a part of the heart, and during
inspiration, when their borders nearly meet behind the sternum, a thin layer of
luno; covers the roots of all the larg-e vessels. Hence the custom of makins: a
patient hold his breath whilst examining the sounds of the heart. But a con-
siderable portion of the heart is always uncovered by the lungs where they
recede from each other below. This "area of the heart's dulness," as it is com-
monly called, is said by Mr. Holden^ to be indicated, roughly, but sufficiently for
practical purposes, by a circle one inch in radius, the centre of which is midway
between the nipple and the end of the sternum. The anterior surface of the
heart is rounded and convex, directed upwards and forwards, and formed chiefly
by the right ventricle and part of the left. Its posterior surface is flattened,
and rests upon the Diaphragm, and is formed chiefly by the left ventricle. The
right border is long, thin, and sharp ; the left border short, but thick and round.
Size. The heart, in the adult, measures five inches in length, three inches
and a half in breadth in the broadest part, and two inches and a half in thick-
ness. The prevalent weight, in the male, varies from ten to twelve ounces ; in
the female from eight to ten : its proportions to the body being as 1 to 169 in
males; 1 to 149 in females. The heart continues increasing in weight, and also
in length, breadth, and thickness, up to an advanced period of life ; this increase
is more marked in men than in women.
Gomponent parts. The heart is subdivided by a longitudinal muscular septum
into two lateral halves, which are named respectively, from their position, right
and left ; and a transverse constriction divides each half of the organ into two
cavities, the upper cavity on each side being called the auricle, the lower the
ventricle. The right is the venous side of the heart, receiving into its auricle
the dark venous blood from the entire body, by the superior and inferior vena
cava, and coronary sinus. From the auricle, the blood passes into the right
ventricle, and from the right ventricle, through the pulmonary artery, into the
lungs. The blood, arterialized by its passage through the lungs, is returned to
the left side of the heart by the pulmonary veins, which open into the left auricle ;
from the left auricle the blood passes into the left ventricle, and from the left
' St. Barth. Hosp. Reports, ii. 208.
51-
802
THE THORAX.
ventricle is distributed, bj tlie aorta and its subdivisions, tlirougli tlie entire
body. This constitutes the circulation of the blood in the adult.
This division of the heart into four cavities is indicated by grooves upon its
surface. The great transverse groove separating the auricles from the ventri-
cles is called the auriculo-ventricular groove. It is deficient, in front, from being
crossed by the root of the pulmonary artery, and contains the trunk of the
nutrient vessels of the heart. The auricular portion occupies the base of the
heart, and is subdivided into two cavities by a medium septum. The two ven-
tricles are also separated into a right and left, by two longitudinal furrows, the
interventricular grooves, which are situated one on the anterior, the other on the
posterior surface : these extend from the base to the apex of the organ ; the former
being situated nearer to the left border of the heart, and the latter to the right.
It follows, therefore, that the right ventricle forms the greater portion of the
anterior surface of the heart, and the left ventricle more of its posterior surface.
Each of these cavities should now be separately examined.
The Eight Auricle is a little larger than the left, its walls somewhat thinner,
measuring about one line ; and its cavity is capable of containing about two
ounces. It consists of two parts, a principal cavity, or sinus, and an appendix
auriculas.
Fig. 462. — The Right Auricle and Ventricle laid open,
the Anterior Walls of both beinff removed.
HyiatU ynfntcU thr^ottcjh
Siyhi Auricula-V,ntrcir,tln.r- ojieni^y
The sinus is the large quadrangular cavity, placed between the two venro
cavfX) ; its walls are extremely thin ; it is connected below with the right ven-
tricle, and internally with the left auricle, being free in the rest of its extent.
The appendix anricvlx^ so called from its fancied resemblance to a dog's car,
is a small conical muscular pouch, the margins of which present a dcntated edge.
It projf(;t3 from the sinus forwards and to the left side, ovcrlap])ing the root of
the ))uliiionary artery.
HEART—VALVES. 803
To examine the interior of the auricle, a transverse incision should be made along its ventric-
ular margin, from its right border to the appendix ; and from the middle of this, a second incision
should be carried upwards along the inner side of the two ven^e cavai.
The following parts present tliemselves for examination :
Openings.
Superior cava.
Inferior cava. , -tti . i •
r^ ■ TT 1 itiustaciiian.
(joronary sinus. V aives. < p
Foramina Thebesii. ^ '^'
Auricnlo- ventricular.
Eelics of foetal j Annulus ovalis.
structure. | Fossa ovalis.
Musculi pectinati.
Openings. The superior vena cava returns the blood from the upper half of
the body, and opens into the upper and front part of the auricle, the direction of
its orifice being downwards and forwards.
The inferior vena cava, larger than the superior, returns the blood from the
lower half of the body, and opens into the lowest part of the auricle, near the
septum, the direction of its orifice being upwards and inwards. The direction
of a current of blood through the superior vena cava would consequently be
towards the auriculo-ventricular orifice; whilst the direction of the blood
through the inferior cava would be towards the auricular septum. This is the
normal direction of the two currents in foetal life.
The tuherculum Loweri is a small projection on the right wall of the auricle,
between the two cavse. This is most distinct in the hearts of quadrupeds; in
man, it is scarcely visible. It was supposed by Lower to direct the blood from
the superior cava towards the auriculo-ventricular opening.
The coronary sinus opens into the auricle, between the inferior vena cava and
the auriculo-ventricular opening. It returns the blood from the substance of
the heart, and is protected by a semicircular fold of the lining membrane of the
auricle, the coronary valve. The sinus, before entering the auricle, is consider-
ably dilated— nearly to the size of the end of the little finger. Its wall is partly
muscular, and, at its junction with the great coronary vein, is somewhat con-
stricted, and furnished with a valve, consisting of two unequal segments.
The /bramma Thehesii are numerous minute apertures, the mouths of small
veins {yense cordis minionse), which open on various parts of the inner surface of
the auricle. They return the blood directly from the muscular substance of the
heart. Some of these foramina are minute depressions in the walls of the heart,
presenting a closed extremity.
The auriculo-ventrictdar opening is the large oval aperture of communication
between the auricle and the ventricle, to be presently described.
Yalves. The Eustachian valve is situated between the anterior margin of
the inferior vena cava and the auriculo-ventricular orifice. It is semilunar in
form, its convex margin being attached to the wall of the vein; its concave
margin, which is free, terminating in two cornua, of which the left is attached
to the anterior edge of the annulus ovalis ; the right being lost on the wall of
the auricle. The valve is formed by a duplicature of the lining membrane of
the auricle, containing a few muscu.lar fibres.
In the foetus^ this valve is of large size, and serves to direct the blood from
the inferior vena cava, through the foramen ovale, into the left auricle.
In the adult^ it is occasionally persistent, and may assist in preventing the
reflux of blood into the inferior vena cava ; more commonly, it is small, and its
free margin presents a cribriform or filamentous appearance; occasionally, it is
altogether wanting.
The coronary valve is a semicircular fold of the lining membrane of the auricle,
protecting the orifice of the coronary sinus. It prevents the regurgitation of
804 THE THORAX.
blood into tlie sinus during the contraction of tlie auricle. This valve is occa-
sionally double.
The fossa ovah's is an oval depression, corresponding to tlie situation of the
foramen ovale in the foetus. It is situated at the lower part of the septum auri-
cularum, above the orilice of the inferior vena cava.
The annulus ovalis is the prominent oval margin of the foramen ovale. It is
most distinct above, and at the sides; below it is deficient. A small slit-like
valvular opening is occasionally found, at the upper margin of the fossa ovalis,
which leads upwards, beneath the annulus, into the left auricle, and is the
remains of the aperture between the two auricles in the foetus.
The muscuU pectinati are small, prominent muscular columns, which run across
the inner surface of the appendix auriculas, and adjoining portion of the Avail of
the sinus. They have received the name, pectinati^ from the fancied resemblance
they bear to the teeth of a comb.
The Eight Yenteicle is triangular in form, and extends from the right
auricle to near the apex of the heart. Its anterior or upper surface is rounded
and convex, and forms the larger part of the front of the heart. Its posterior
or under surface is flattened, rests upon the Diaphragm, and forms only a small
part of the back of the heart. Its inner wall is formed by the partition between
the two ventricles, the septum, ventriculorum^ the surface of which is convex, and
bulges into the cavity of the right ventricle. Superiorly, the ventricle forms a
conical prolongation, tlie infundihulum^ or conus arteriosus, from which the
pulmonary artery arises. The walls of the right ventricle are thinner than
those of the left, the proportion between them being as 1 to 3 or 4. The wall
is thickest at the base, and gradually becomes thinner towards the apex. The
cavity, which equals that of the left ventricle, is capable of containing about
two fluidounces.
To examine the interior, an incision should be made a little to the right of the anterior ven-
tricular groove from the pulmonary artery to the apex of the heart, and should be carried up
from thence along the right border of the ventricle, as far as the auriculo-ventricular opening.
The following parts present themselves for examination : —
Q • ( Auriculo-ventricular.
^ ^ ' * 1 Opening of the pulmonary artery.
Valves. . . JTnc^fPid.
( Semilunar.
And a muscular and tendinous apparatus connected with the tricuspid valve: —
Columnae carnea3. Chordce tendinete.
The auriculo-ventricular orifice is the large oval aperture of communication
between the auricle and ventricle. It is situated at the base of the ventricle,
near the right border of the heart, and corresponds to the centre of the sternum
between the third costal cartilages. The opening is about an inch in diameter,^
oval from side to side, surrounded by a fibrous ring, covered by the lining mem-
brane of the heart, and rather larger than the corresponding aperture on the
left side, being sufficiently large to admit the ends of three fingers. It is guarded
by the tricuspid valve.
The opening of the pulmonary artery is circular in form, and situated at the
summit of the conus arteriosus, close to the scjjtum vcntriculorum. It is placed
on the loft side of the aiu'icnlo-vcntricular 0})ening, upon the anterior aspect of
' In Iho Pafhnlnrjzral Tramtartinns, vol. vi. p. 110, Pr. Peacock has given some careful
researches upon the weight and dimensions of tlie heart in health and disease. He states, as the
result of Ills investigations, that, in tlie healthy adult heart, the right auriculo-ventricular aperture
has a mean circumference of .54.4 lines, or -ifj inches; the left auriculo-ventricular aperture a
mean circunirer('n(;(! of AA.W lines, or .'5,'-* inches; the pulmonic orifice of 40 Hues, or 3iiJ inches;
and the aortic orifice of :{").. 0 lines, or Bj^ inches; but the dimensions of the orifices varied greatly
in different cases, the right auricido-ventricidar aperture having a range of from 45 to GO lines,
and the others in the same proportion.
HEART—RIGHT VENTRICLE. 805
tlie heart, and corresponds to tlie upper border of the third costal cartilage of
the left side, close to the sternum. Its orifice is guarded by the pulmonary
semilunar valves.
The tricusind valve consists of three segments of a triangular or trapezoidal
shape, formed by a duplicature of the lining membrane of the heart, strengthened
by a layer of fibrous tissue, and containing, according to Kurschner and Senac,
muscular fibres. These segments are connected by their bases to the auriculo-
ventricular orifice, and by their sides with one another, so as to form a con-
tinuous annular membrane, which is attached round the margin of the auriculo-
ventricular opening, their free margins and ventricular surfaces afibrding
attachment to a number of delicate tendinous cords, the chordse tendinese. The
largest and most movable segment is placed towards the left side of the auriculo-
ventricular opening ; interposed between that opening and the pulmonary artery.
Another segment corresponds to the front of the ventricle ; and a third to its
posterior wall. The central part of each segment is thick and strong; the lateral
margins are thin and indented. The chords tendinese are connected with the
adjacent margins of the principal segments of the valve, and are further attached
to each segment in the following manner: 1. Three or four reach the attached
margin of each segment, where they are continuous with the auriculo-ventricular
tendinous ring. 2. Others, four to six in number, are attached to the central
thickened part of each segment. 3. The most numerous and finest are con-
nected with the marginal portion of each segment.
The columnse carnese are the rounded muscular columns which project from
nearly the whole of the inner surface of the ventricle, excepting near the open-
ing of the pulmonary artery. They may be classified, according to their mode
of connection with the ventricle, into three sets. The first set merely form
prominent ridges on the inner surface of the ventricle, being attached by their
entire length on one side, as well as by their extremities. The second set are
attached by their two extremities, but are free in the rest of their extent ; whilst
the third set [musculi jpapillares\ three or four in number, are attached by one
extremity to the wall of the heart, the opposite extremity giving attachment to
the chordse tendinese. The tricuspid valve is situated behind the middle of the
sternum, about the level of the fourth costal cartilage.
The semilunar valves^ three- in number,^ guard the orifice of the pulmonary
artery. They consist of three semicircular folds, formed by a duplicature of the
lining membrane, strengthened by fibrous tissue. They are attached, by their
convex margins, to the wall of the artery, at its junction with the ventricle, the
straight border being free, and directed upwards in the course of the vessel,
against the sides of which the valve-flaps are pressed during the passage of the
blood along the artery. The free margin of each is somewhat thicker than the
rest of the valve, is strengthened by a bundle of tendinous fibres, and presents,
at its middle, a small projecting fibro-cartilaginous nodule, called corpus Arantii.
From this nodule, tendinous fibres radiate through the valve to its attached
margin, and these fibres form a constituent part of its substance throughout its
whole extent, excepting two narrow lunated portions, placed on either side of
the nodule, immediately behind the free margin ; here, the valve is thin, and
formed merely by the lining membrane. During the passage of the blood along
the pulmonary artery, these valves are pressed against the sides of the cylinder,
and the course of the blood along the tube is uninterrupted; but during the
ventricular diastole, when the current of blood along the pulmonary artery is
checked, and partly thrown back by its elastic walls, these valves become imme-
diately expanded, and effectually close the entrance of the tube. When the
valves are closed, the lunated portions of each are brought into contact with
' The pulmonary semilunar valves have been found to be two in number instead of three (Dr.
Hand, of St. Paul, Minn., in the " North- Western Med. and Surg. Journ.," July, 1873), and the
same variety is more frequently noticed in the aortic semilunar valves.
806
THE THORAX,
one another by their opposed surfaces, the three fibro-cartilaginous nodules
filling up the small triangular space that would be otherwise left by the approxi-
mation of the three semilunar folds.
Between the semilunar valves and the commencement of the pulmonary artery
are three pouches or dilatations, one behind each valve. These are the pulmo-
nary sinuses {sinuses of Valsalva). Similar sinuses exist between the semilunar
valves and the commencement of the aorta ; they are larger than the pulmonary
sinuses. The blood, in its regurgitation towards the heart, finds its way into
these sinuses, and so shuts down the valve-flaps. The pulmonary valves are
situated behind the junction of the left third rib with the sternum.
The Left Aueicle is rather smaller but thicker than the right, measuring
about one line and a half; it consists, like the right, of two parts, a principal
cavity or sinus, and an appendix auriculee.
The sinus is cuboidal in form, and coucealed in front by the pulmonary artery
and aorta ; internally, it is separated from the right auricle by the septum auricu-
larum; behind, it receives on each side the pulmonary veins, being free in the
rest of its extent. .
Fig. 463. — The Left Auricle and Ventricle laid open, the anterior "Walls of bath being removed.
passed the Aortic openinij
The appendix auriculve is somewhat constricted at its junction with the auricle;
it is longer, narrower, and more curved than that of the right side, and its
margins more deeply indented, presenting a kind of foliated appearance. Its
direction is forwards and towards the right side, overlapping the root of the
pulmonary artery.
In order to examine its interior, a horizontal incision shonld be made along the atiaclied border
of the auricle to the ventricle; and from llie middle of this, a .second incision should be carried
upwards.
The following ]>.'ii-ts tlicu present thcm.sclves f(;r examination: —
'^I'lio openings of tlic four pulmonary veins.
Auriculo-vcntrJcular opening.
Mu.sculi pcctinali.
HEART—LEFT VENTRICLE. 807
Tlie pulmonary veins^ four in number, open, two into the right, and two into
tlie left side of tlie auricle. The two left veins frequently terminate by a
common opening. They are not provided with valves.
The avTiculo -ventricular opening is the large oval aperture of communication
between the auricle and ventricle. It is rather smaller than the corresponding
opening on the opposite side (see note, p. 804).
The musculi pectinati are fewer in number and smaller than on the right side ;
they are confined to the inner surface of the appendix.
On the inner surface of the septum auricularum may b© seen a lunated im-
pression, bounded below by a crescentic ridge, the concavity of which is turned
upwards. The depression is just above the fossa ovalis in the right auricle.
The Left Yentricle is longer and more conical in shape than the right ven-
tricle. It forms a small part of the left side of the anterior surface of the heart,
and a considerable part of its posterior surface. It also forms the apex of the
heart by its projection beyond the right ventricle. Its walls are much thicker
than those of the right ventricle, the proportion being about 3 to 1. They are
also thickest in the broadest part of the ventricle, becoming gradually thinner
towards the base, and also towards the apex, which is the thinnest part.
Its cavity should be opened, by making an incision through its anterior wall along the left
side of the ventricular septum, and carrying it round the apex and along its posterior surface to
the auriculo-ventricular opening.
The following parts present themselves for examination : —
^ • j Auriculo-ventricular. -^ -, ( Mitral.
P S • I Aortic. ■ I Semilunar.
Chordre tendineee. Columnje carneae.
The auriculo-ventricular opening is placed to the left of the aortic orifice,
beneath the right auriculo-ventricular opening, opposite the centre of the
sternum. It is a little smaller than the corresponding aperture of the opposite
side ; and, like it, is broader in the transverse than in the antero-posterior
diameter. It is surrounded by a dense fibrous ring, covered by the lining mem-
brane of the heart, and guarded by the mitral valve.
The aortic opening is a small circular aperture, in front and to the right side
of the auriculo-ventricular, from which it is separated by one of the segments of
the mitral valve. Its orifice is guarded by the semilunar valves. Its position
corresponds to the sternum, on a line with the lower border of the third
costal cartilage.
The onitral valve is attached to the circumference of the auriculo-ventricular
orifice in the same way that the tricuspid valve is on the opposite side. It is
formed by a duplicate of the lining membrane, strengthened by fibrous tissue,
and contains a few muscular fibres. It is larger in size, thicker, and altogether
stronger than the tricuspid, and consists of two segments of unequal size. The
larger segment is placed in front, between the auriculo-ventricular and aortic
orifices, and is said to prevent the filling of the aorta during the distension of
the ventricle. Two smaller segments are usually found at the angle of junction
of the larger. The mitral valve-flaps are furnished with chordae tendine^, the
mode of attachment of which is precisely similar to those on the right side ; but
they are thicker, stronger, and less numerous. The mitral valve lies in the
third intercostal space, about an inch from the left border of the sternum.
The semilunar valves surround the orifice of the aorta; they are similar in
structure, and in their mode of attachment, to those of the pulmonary artery.
They are, however, larger, thicker, and stronger than those of the right side ;
the lunulee are more distinct, and the corpora Arantii larger and more promi-
nent. Between each valve and the cylinder of the aorta is a deep depression,
the sinus aortici (sinuses of Valsalva) ; they are larger than those at the root of
the pulmonary artery. The aortic valves lie close behind the left border of the
sternum, in the third intercostal space.
808 THE THORAX.
The columnse carnese admit of a subdivision into three sets, like those upon
the right side ; but they are smaller, more numerous, and present a dense inter-
lacement, especially at the apex, and upon the posterior wall. Those attached
by one extremity only, the musculi papiUares, are two in number, being con-
nected one to the anterior, the other to the posterior wall ; they are of large
size, and terminate by free rounded extremities, from which the chordas tendi-
neee arise.
The Endocardium is the serous membrane which lines the internal surface of
the heart ; it assists in forming the valves by its reduplications, and is continu-
ous with the lining membrane of the great bloodvessels. It is a thin, smooth,
transparent membrane, giving to the inner surface of the heart its glistening
appearance. It is more opaque on the left than on the right side of the heart,
thicker in the auricles than in the ventricles, and thickest in the left auricle.
It is thin on the musculi pectinati, and on the columnge carnege; but thicker on
the smooth part of the auricular and ventricular walls, and on the tips of the
musculi papillares.
Structure. The heart consists of muscular fibres, and of fibrous rings which
serve for their attachment.
^h.Q fibrous rings surround the auriculo- ventricular and arterial orifices : they
are stronger upon the left than on the right side of the heart. The auriculo-
ventricular rings serve for the attachment of the muscular fibres of the auricles
and ventricles, and also for the mitral and tricuspid valves ; the ring on the
left side is closely connected, by its right margin, with the aortic arterial ring.
Between these and the right auriculo-ventricular ring, is a fibro-cartilaginous
mass ; and in some of the larger animals, as the ox and elephant, a portion of
bone.
The fibrous rings surrounding the arterial orifices serve for the attachment of
the great vessels and semilunar valves. Each ring receives, by its ventricular
margin, the attachment of the muscular fibres of the ventricles ; its opposite
margin presents three deep semicircular notches, within which the middle coat
of the artery (which presents three convex semicircular segments) is firmly
fixed ; the attachment of the artery to its fibrous ring being strengthened by
the thin cellular coat and serous membrane externally, and by the endocardium
within. It is opposite the margins of these semicircular notches, in the arterial
rings, that the endocardium, by its reduplication, forms the semilunar valves,
the fibrous structure of the ring being continued into each of the segments of
the valve at this part. The middle coat of the artery in this situation is thin,
and the sides of the vessel are dilated to form the sinuses of Valsalva.
The muscular structure of the heart consists of bands of fibres, which present
an exceedingly intricate interlacement. They are of a deep red color, and
marked with transverse striae (p. 58).
The muscular fibres of the heart admit of a subdivision into two kinds: those
of the auricles, and those of the ventricles ; which are quite independent of one
another.
Fibres of the auricles. These are disposed in two layers: a superficial layer
common to botli cavities, and a deep layer proper to each. The superficial
fihrf'S are most distinct on the anterior surface of the auricles, across the bases of
which they run in a transverse direction, forming a thin, but incomplete, layer.
Some of these fibres pass into the septum auricularum. The internal or deep
fibres proper to each auricle consist of two sets, looped and annular fibres. The
hoped fihres pass upwards over each auricle, being attached by two extremities
to the corresponding auriculo-ventricular rings, in front and behind. The anoiu-
lar fibres surround tlie whole extent of the appendices auricuhv., and are contin-
ued upon the walls of the vcntc cavro and coronary sinus on the right side, and
upon the pulmonary veins on the left side, at their connection with the heart.
In the appendices, they interlace with the longitudinal fibres.
HEART—STRUCTURE. 809
The fibres of the ventricles are arranged in numerous layers, of wliicli Petti-
grew^ describes seven. Other anatomists have regarded them differently, and
indeed there must be some uncertainty on the subject, for the layers are not
independent of each other, but their fibres are interlaced to a considerable ex-
tent. And it has been observed that as Pettigrew's observations were made
chiefly on the hearts of the lower animals, they may not apply exactly to man.
Yet as this description has been received by some of the best anatomists, and is
supported by a large series of preparations, it seems best to adopt it.
The general result of these investigations may be very briefly stated as fol-
lows. In the left ventricle the fibres of the first or most external layer are
continuous with those of the seventh or most internal, those of the second with
the sixth, and those of the third with the fifth, while the fourth or central layer
appears to be single. The general direction of the fibres of the external layer
is nearly vertical, but inclining somewhat from left to right as they run down-
wards ; the direction of the fibres of the internal layer is just the reverse, nearly
vertical but running upwards from left to right; those of the second layer run
more obliquely downwards, from left to right, and those of the sixth with a
corresponding obliquity in the reversed directions. The obliquity of the fibres
of the third layer is greater ; in fact, they approach the horizontal, as do those
of the fifth in the reversed direction, while the fibres of the fourth layer run
pretty nearly horizontal. The thickness of the layers increases from without
inwards, so that the fourth layer, which is the middle in order of sequence, lies
nearer the outer than the inner surface of the ventricular wall. The fibres of
the external or superficial layer arise, as a rule, from the auriculo- ventricular
rings and from the fibrous ring surrounding the aorta, but a few of them are
continued beneath the rings into the columnse carnete.^ They curve round at
the apex in a spiral, which forms the whorl or vortex, those from the anterior
surface of the heart curving round to enter the apex posteriorly, and vice versa.
From the apex they are traced up into the seventh layer, which is much thicker,
and from which the musculi papillares and columnas carneas are chiefly formed.
The apex of the heart is formed exclusively of the fibres of this first layer (or
first and seventh), so that, when it is removed, the ventricle is opened. And
the successive layers terminate further and further from the apex, an arrange-
ment which has led to their fibres being described as shorter, which Pettigrew
doubts, attributing the shortness of the layers to the different direction of the
fibres, not to any difference in length in the individual fibres. Since the deeper
layers do not descend to the apex, this is the tliinnest part of the ventricle,
measuring only ^th of an inch in thickness even in the heart of an ox.
The fibres of the deeper layers are not connected with the auriculo- ventricu-
lar rings, but pass below them, each layer terminating a little below the more
superficial layer which wraps round it, though the difference in this respect is
not so great as in their depth towards the apex.
The fibres of the first layer pass across the septum from one ventricle to the
other, an arrangement particularly well seen at the back of the heart, where
there is a set of transverse fibres described by Pettigrew as the "hingelike
fibres" of the back of the heart, and the three subjacent layers also take part in
the formation of both ventricles ; but when the fourth layer is removed, the two
ventricles are entirely severed from each other posteriorly. The septum is
formed of the fibres of both ventricles applied to each other.
The general arrangement of the fibres of the right ventricle is the same as
that of the left, but the external fibres do not pass in to be continuous with the
internal at a single point — the apex — -but all along the anterior coronary groove.
Its fibres are more delicate than those of the left, and it is regarded by Pettigrew
' Phil. Trans. 1864.
^ " It is a great mistake to imagine that all the fibres of the ventricles arise from the anriculo-
ventricular tendinous rings, the fact being that, with the exception of the fibres of the first and
seventh layers, they are continuous beneath them." — Pettigrew, op. cit. p. 456, note.
810 THE THORAX.
as formed out of tlie left ventricle by a kind of reflection inwards of the wall
of the single cavity of wliicli the ventricles consist at one period of the foetal
life (see Introduction). He points out that the heart at that period may be
supposed to be represented by an open tube formed of spiral fibres. If, now a
portion of this tube or cylinder were pushed down to meet the opposite wall, to
which the fibres of the reflected portion adhere, and with which they coalesce,
there would be formed an offset from the common ventricular cavity, formed
partly of common and partly of special fibres, as is the case in the heart. At
this early period the outer layers are not formed and the apex is still unclosed.
Their formation closes in the apex and completes the walls of the ventricles.
If this is the case the septum must be formed of two elements or sets of fibres,
one proper to the original single ventricle, and therefore in after life proper to
the left ventricle, the other set formed from the reflected or reduplicated fibres
which now form the right ventricle.^ To these of course the fibres which cross
over from one ventricle to the other may be added. Pettigrew regards the por-
tion of the septum which belongs to the left ventricle as twice that which
belongs to the right. For many interesting particulars with regard to the
arrangement of the fibres and the shape of the cavities the reader must be referred
to the original paper.
Vessels and Nerves. The arteries supplying the heart are the left or anterior
and right or posterior coronary (p. 469).
The veins accompany the arteries, and terminate in the right auricle. They
are the great cardiac vein, the small or anterior cardiac veins, and the vense
cordis minimas {yense Thehesii) (p. 587).
The lymphatics terminate in the thoracic and right lymphatic ducts.
The nerves are derived from the cardiac plexuses, which are formed partly
from the cranial nerves, and partly from the sympathetic. They are freely
distributed both on the surface, and in the substance of the heart; the separate
filaments being furnished with small ganglia.^
Peculiakities in the Vasculae System of the Foetus.
The chief peculiarities in the heart of the foetus are the direct communication
between the two auricles through the foramen ovale, and the large size of the
Eustachian valve. There are also several minor peculiarities. Thus, the posi-
tion of the heart is vertical until the fourth month, when it commences to
assume an oblique direction. Its size is also very considerable, as compared
with the body, the proportion at the second month being as 1 to 50 : at birth
it is as 1 to 120 : whilst in the adult, the average is about 1 to 160. At an
early period of foetal life, the auricular portion of the heart is larger than the
ventricular, the right auricle being more capacious than the left; but towards
birth, the ventricular portion becomes the larger. The thickness of both ventri-
cles is, at first, about equal; but, towards birth, the left becomes much the
thicker of the two.
The /oramew ovale is situated at the lower and back part of the scj'ytiim auricu-
lariim, forming a communication between the auricles. It attains its greatest
size at the sixth month.
The Eustachian valve is developed from the anterior border of the inferior
' If tlif; fjonoriil idea of tbia is not at once obvious, it will become so by takiiij; a roll of paper,
callinfT on(! side u\ il tlic posterior and tlie other the anterior, and bending' it at llie ri^lit side of
its iiii(idl(! till llie anterior touelies the posterior snrfaee. The larp-er part to the left of the middle
line rcfiresents the left ventricle, the smaller the rif;ht, and the doul)le fold in the middle the
Beptum ; then, if the refief^ted yiarts where they tonch are "•nmnied to each other, this will repre-
Bent tli(! coalescence; of the se))tiiin with the onter wall, whereby the riyht ventricle becomes a
separate tube from the left, '{'lie lower ojx^niiifi-s of th(>s(! two tni)i>s are closed in by the <zrowth
of the external layers.
"^ For full and accurate descriptions of the nerves and gan{,^lia of the heart, the student is
referred to Dr. K. Lee's papers on the subject.
VASCULAE SYSTEM OF FGETUS.
811
vena cava at its entrance into tlie auricle. It is directed upwards on tlie left side
of the opening of this vein, and serves to direct the blood from the inferior vena
cava through the foramen ovale into the left auricle.
The peculiarities in the arterial system of the foetus are the communication
between the pulmonary artery and descending part of the arch of the aorta, by
means of the ductus arteriosus, and the communication between the internal
iliac arteries and the placenta, by means of the umbilical arteries.
Fisr. 464.— Plan of the Foetal Circulation.
Intenai JUac aX
In this plan the figured arrows represent the kind of blood, as well as the direction which it
takes in the vessels. Thus — arterial blood is figured^*' ••••>■ ; venous blood, >»- >■•
mixed (arterial and venous) blood, ?^>'» — • — •>.
812 THE THORAX.
The ductus arteriosus is a short tube, about half an incli in length at birth,
and of the diameter of a goose-quill. In the early condition, it forms the con-
tinuation of the pulmonary artery, and opens into the arch of the aorta, just
below the origin of the left subclavian artery ; and so conducts the chief part
of the blood from the right ventricle into the descending aorta. When the
branches of the pulmonary artery have become larger relatively to the ductus
arteriosus, the latter is chiefly connected to the left pulmonary artery; and the
fibrous cord, which is all that remains of the ductus arteriosus in later life, will
be found to be attached to the root of that vessel.
The umhilical, or hypogastric arteries^ arise from the internal iliacs, in addition
to the branches given oft' from those vessels in the adult. Ascending along the
sides of the bladder to its fundus, they pass out of the abdomen at the umbilicus,
and are continued along the umbilical cord to the placenta, coiling round the
umbilical vein. They return to the placenta the blood which has circulated in
the system of the foetus.
The peculiarity in the venous system of the foetus is the communication
established between the placenta and the liver and portal vein through the um-
bilical vein, and with the inferior vena cava by the ductus venosus.
FcETAL Circulation.
The arterial blood destined for the nutrition of the foetus is carried from the
placenta to the foetus, along the umbilical cord, by the umbilical vein. The
umbilical vein enters the abdomen at the umbilicus, and passes upwards along
the free margin of the suspensory ligament of the liver to the under surface of
that organ, where it gives off two or three branches to the left lobe, one of which
is of large size ; and others to the lobus quadratus and lobulus Spigelii. At the .
transverse fissure it divides into two branches ; of these, the larger is joined by
the portal vein, and enters the right lobe ; the smaller branch continues onwards
under the name of the ductus venosus, and joins the left hepatic vein at the
point of junction of that vessel with the inferior vena cava. The blood, there-
fore, which traverses the umbilical vein, reaches the inferior cava in three diff-
erent ways. The greater quantity circulates through the liver with the portal
venous blood, before entering the vena "cava by the hepatic veins; some enters
the liver directly, and is also returned to the inferior cava by the hepatic veins :
the smaller quantity passes directly into the vena cava, by the junction of the
ductus venosus with the left hepatic vein.
In the inferior cava, the blood carried by the ductus venosus and hepatic
veins becomes mixed with that returning from the lower extremities and viscera
of the abdomen. It enters the right auricle, and, guided by the Eustachian
valve, passes through the foramen ovale into the left auricle, where it becomes
mixed with a small quantity of blood returned from the lungs by the pulmonary
veins. From the left auricle it passes into the left ventricle; and, from the left
ventricle, into the aorta, from whence it is distributed almost entirely to the
head and upper extremities, a small quantity being probably carried into the
descending aorta. From the head and upper extremities the blood is returned
by the branches of the superior vena cava to the right auricle, where it becomes-
mixed with a small portion of the blood from the inferior cava. From the
right auricle it descends over the Eustachian valve into the right ventricle ; and,
from the right ventricle, passes into the pulmonary artery. The lungs of the
footuH being solid, and almost im|)crvious, only a small quantity of the bl(~)od of
the pvdmonary artery is distributed to them, by the right and loft pulmonary
arteries, wliich is returned l)y the pulmonary veins to the left auricle: the greater
part passes tlirough the ductus arteriosus into the commencement of the de-
ficcnding aorta, where it becomes mixed with a small quantity of blood trans-
mitted by the left ventricle into the aorta. Along this vessel it descends to
FCETAL CIRCULATION. 813
supply tlie lower extremities and viscera of the abdomen and pelvis, tlie chief
portion being, however, conveyed by the umbilical arteries to the placenta.
From the preceding account of the circulation of the blood in the foetus, it
will be seen : —
1. That the placenta serves the double purpose of a respiratory and nutritive
organ, receiving the venous blood from the foetus, and returning it again reoxy-
genated, and charged with additional nutritive material.
2. That nearly the whole of the blood of the umbilical vein traverses the liver
before entering the inferior cava; hence the large size of this organ, especially at
an early period of fcetal life.
3. That the right auricle is the point of meeting of a double current, the blood
in the inferior cava being guided by the Eustachian valve into the left auricle,
whilst that in the superior cava descends into the right ventricle. At an early
period of foetal life, it is highly probable that the two streams are quite distinct :
for the inferior cava opens almost directly into the left auricle, and the Eusta-
chian valve would exclude the current along the vein from entering the right
ventricle. At a later period, as the separation between the two auricles becomes
more distinct, it seems probable that some mixture of the two streams must take
place.
4. The blood carried from the placenta to the foetus by the umbilical vein,
mixed with the blood from the inferior cava, passes almost directly to the arch
of the aorta, and is distributed by the branches of that vessel to the head and
upper extremities : hence the large size and perfect development of those parts
at birth.
5. The blood contained in the descending aorta, chiefly derived from that
which has already circulated through the head and limbs, together with a small
quantity from the left ventricle, is distributed to the lower extremities: hence
the small size and imperfect development of these parts at birth.
Changes in the Vascular System at Birth.
At birth, when respiration is established, an increased amount of blood from
the pulmonary artery passes through the lungs, which now perform their of&ce
as respiratory organs, and, at the same time, the placental circulation is cut off".
The foramen ovale becomes gradually closed in by about the tenth day afte"r
birth ; a valvular fold rises up on the left side of its margin, and ultimately
above its upper part; this valve becomes adherent to the margins of the foramen
for the greater part of its circumference, but above a valvular opening is left
between the two auricles, which sometimes remains persistent.
The ductus arteriosus begins to contract immediately after respiration is estab-
lished, becomes completely closed from the fourth to the tenth day, and ulti-
mately degenerates into an impervious cord, which serves to connect the left
pulmonary artery to the concavity of the arch of the aorta.
Of the umbilical or hypogastric arteries, the portion continued on to the bladder
from the trunk of the corresponding internal iliac remains pervious, as 1he supe-
rior vesical artery ; and the part between the fundus of the bladder and the
umbilicus becomes obliterated between the second and fifth days after birth, and
forms the anterior true ligament of the bladder.
The umbilical veins and ductus venostis become completely obliterated between
the second and fifth days after birth, and ultimately dwindle to fibrous cords;
the former becoming the round ligament of the liver, the latter, the fibrous cord,
which, in the adult, may be traced along the fissure of the ductus venosus.
Organs of Voice and Respiration.
Fig. 465.— Side View of the Thyroid
and Cricoid CartiUiges.
The Laeynx.
The Larynx is tlie organ of voice, placed at the upper part of tlie air-passage.
It is situated between the trachea and base of the tongue, at the upper and fore
part of the neck, where it forms a considerable projection in the middle line.
On either side of it lie the great vessels of the neck ; behind, it forms part of
the boundary of the pharynx, and is covered by the mucous membrane lining
that cavity.
The Larynx is narrow and cylindrical below, but broad above, where it pre-
sents the form of a triangular box, flattened behind and at the sides, whilst in
front it is bounded by a prominent vertical ridge. It is composed of cartilages,
which are connected together by ligaments and moved by numerous muscles :
the interior is lined by mucous membrane, and supplied with vessels and nerves.
The Cartilages of the larynx are nine in number, three single, and three
pairs : —
Thyroid. Two Arytenoid.
Cricoid. Two Cornicula Laryngis.
Epiglottis. Two Cuneiform.
The Thyrrjid {Svpio^^ a shield) is the largest cartilage of the larynx. It consists
of two lateral lamellas or alee, united at an acute angle in front, forming a vertical
projection in the middle line which is promi-
nent above, and called the pomum Adami. This
projection is subcutaneous, more distinct in the
male than in the female, and occasionally sepa-
rated from the integument by a bursa mucosa.
Each lamella is quadrilateral in form. Its
outer surface presents an oblique ridge, which
jDasses downwards and forwards from a tubercle,
situated near the root of the superior cornu.
This ridge gives attachment to the Sterno-thy-
roid and Thyro-hyoid muscles; the portion of
cartilage included between it and the posterior
border, to part of the Inferior constrictor muscle.
The inner surface of each ala is smooth, con-
cave, and covered by mucous membrane above
and behind; but in front, in the receding angle
formed by their junction, are attached the
epiglottis, the true and false chordas vocales,
the Thyro-arytenoid, and Thyro-epiglottidean '
muscles.
The upper horder of the thyroid cartilage is
deeply notched in the middle line, immediately
above the pomum Ada-mi, whilst on cither side
it is slightly concave. This border gives attach-
ment throughout its whole extent to the thyro-
liyoid membrane.
The hv)er harder is connected to tlie cricoid cartilage, in the median line, by
the crico-thyroid membrane; and, on each side, by the Crico-thyroid muscle.
The posterior borders^ thick and njiiudcd, tcniiinatc, above, in the superior
(814)
CARTILAGES OF LARYNX,
815
cornua ; and, below, in tlie inferior cornua. The two superior cornna are long
and narrow, directed backwards, upwards, and inwards; and terminate in a
conical extremity, which, gives attachment to the thyro-hyoid ligament. The
two inferior cornua are short and thick ; they pass forwards and inwards, and
present, on their inner surfaces, a
Fiar. 466.
-The Cartilages of the Larynx.
Posterior View.
EPIGLOTTIS
inner
small, oval, articular facet for articu-
lation with the side of the cricoid
cartilage. The posterior border re-
ceives the insertion of the Stylo-
pharyngens and Palato-pharyngeus
muscles on each side.
The Cricoid Cartilage is so called
from its resemblance to a signet
ring (xpt'xoj, a ring). It is smaller
but thicker and stronger than the
thyroid cartilage, and forms the
lower and back part of the cavity
of the larynx.
Its anterior half is narrow, con-
vex, affording attachment in front
and at the sides to the Crico-thyroid
muscles, and, behind those, to part
of the Inferior constrictor.
Its posterior half is very broad,
both from side to side and from
above downwards; it presents in
the middle line a vertical ridge for
the attachment of the longitudinal
fibres of the oesophagus; and on
either side a broad depression for
the Crico-arytaenoideus posticus
muscle.
At the point of junction of the
two halves of the cartilage on either
side is a small round elevation, for
articulation with the inferior cornu
of the thyroid cartilage.
The lower border of the cricoid
cartilage is horizontal, and con-
nected to the upper ring of the tra-
chea by fibrous membrane.
Its upper border is directed ob-
liquely upwards and backwards,
owing to the great depth of its
posterior surface. It gives attach-
ment, in front, to the crico-thyroid
membrane ; at the sides, to part of the same membrane and to the lateral Crico-
arytenoid muscle; behind, the highest point of the upper border is surmounted
on each side by a smooth oval surface, for articulation with the arytenoid carti-
lage. Between the articular surfaces is a slight notch, for the attachment of
part of the Arytenoideus muscle.
The inner surface of the cricoid cartilage is smooth, and lined by mucous
membrane.
The Arytenoid Cartilages are so called from the resemblance they bear, when
approximated, to the mouth of a pitcher (dpiiraiva, a pitcher). They are two in
number, and situated at the ujDper border of the cricoid cartilage, at the back of
ARYTENOID
f);;»TlCl.iETLATCaAL13
cEJCoia
^rtic ul<t,-j» fa,cet.
cf Thyroid C
•Irytenotd Car^^'". Zase
816 ORGANS OF VOICE AND RESPIRATION.
tlie larynx. Eacli cartilage is pyramidal in form, and presents for examination
three surfaces, a base, and an apex.
The posterior surface is triangular, smooth, concave, and lodges part of the
Arytenoid muscle.
The anterior surface^ somewhat convex and rough, gives attachment to the
Thyro-arytenoid muscle, and to the false vocal cord.
The internal surface is narrow, smooth, and flattened, covered by mucous
membrane, and lies almost in apposition with the cartilage of the opposite side.
The base of each cartilage is broad, and presents a concave smooth surface,
for articulation with the cricoid cartilage. Of its three angles, the external is
short, rounded, and prominent, receiving the insertion of the posterior and
lateral Crico-arytenoid muscles. The anterior angle, also prominent, but more
pointed, gives attachment to the true vocal cord.
The apex of each cartilage is pointed, curved backwards and inwards, and
surmounted by a small conical- shaped, cartilaginous nodule, comiculum laryngis
(cartilage of Santorini). This cartilage is sometimes united to the arytenoid,
and serves to prolong it backwards and inwards. To it is attached the aryteno-
epiglottidian fold.
The cuneiform cartilages (cartilages of Wrisberg) are two small, elongated,
cartilaginous bodies, placed one on each side, in the fold of mucous membrane
which extends from the apex of the arytenoid cartilage to the side of the epi-
glottis {aryteno-epiglottidean fold)} they give rise to small whitish elevations on
the inner surface of the mucous membrane, just in front of the arytenoid carti-
lages.
The epiglottis is a thin lamella of fibro- cartilage, of a yellowish color, shaped
like a leaf, and placed behind the tongue in front of the superior opening of the
larynx. During respiration, its direction is vertically upwards, its free extremity
curving forwards towards the base of the tongue ; but when the larynx is drawn
up beneath the base of the tongue during deglutition it is carried downwards
and backwards, so as to completely close the opening of the larynx. Its free
extremity is broad and rounded; its attached end is long and narrow, and con-
nected to the receding angle between the two alse of the thyroid cartilage, just
below the median notch, by a long, narrow, ligamentous band, the thyro-epi-
glottic ligament. It is also connected to the posterior surface of the body of the
hyoid bone by an elastic ligamentous band, the hyo-epiglottic ligament.
Its anterior or lingual surface is curved forwards towards the tongue, and
covered by mucous membrane, which is reflected on to the sides and base of
the organ, forming a median and two lateral folds, the glosso-epiglottidean liga-
ments.
Its posterior or laryngeal surface is smooth, concave from side to side, convex
from above downwards, and covered by mucous membrane; when this is
removed, the surface of the cartilage is seen to be studded with a number of
small mucous glands, which are lodged in little pits upon its surface. To its
sides the aryteno-epiglottidean folds are attached.
Structure. The epiglottis, cuneiform cartilages, and cornicula laryngis are
composed of yellow cartilage, which shows little tendency to ossification ; but
the other cartilages resemble in structure the costal cartilages, becoming more
or less ossified in r)ld age.
Ligaments. The Ijgfimcnts of the larynx are extrivsic, i. c, those connecting
the thyroid cartilage with the os hyoides; and intrinsic, those which connect
, the several cartilaginous segments to each other.
The ligaments connecting the thyroid cartilage with the os hyoides arc three
in number: the thyro-hyoid incinbrane, and the two lateral thyro-liyoid
ligaments.
The thyro-hyoid memhrane is a broad, fibro-clastio, membranous layer, attached
below to tlie upper border of the thyroid cartilage, and abcwc to the upper
border of the inner surface of the liyoid bone: being separated froui the poste-
LIGAMENTS OF LARYNX.
817
rior surface of tlie liyoid bone by a synovial bursa. It is tliicker in the middle
line than at either side, in which situation it is pierced by the superior laryngeal
vessels and nerve.
The two lateral thyrohyoid ligaments are rounded, elastic cords, which pass
between the superior cornua of the thyroid cartilage and the extremities of the
greater cornua of the hyoid bone. A small cartilaginous nodule {cartilayo
triticea), sometimes bony, is found in each.
The ligaments connecting the thyroid cartilage to the cricoid are also three
in number : the crico- thyroid membrane, and the capsular ligaments and syno-
vial membrane.
The crico-thyroid memhrane is composed mainly of j^ellow elastic tissue. It
is of triangular shape ; thick in front, where it connects together the contiguous
margins of the thyroid and cricoid cartilages; thinner at each side, where it
extends from the superior border of the cricoid cartilage to the inferior margin
of the true vocal cords, with which it is closely united m front.
The anterior portion of the crico-thyroid membrane is convex, concealed on
each side by the Crico-thyroid muscle, subcutaneous in the middle line, and
crossed horizontally by a small anastomotic arterial arch, formed by the junction
of the two crico-thyroid arteries.
The lateral portions are lined internally by mucous membrane, and covered
by the lateral Crico-arytenoid and Thyro-arytenoid muscles.
A capsular Ujament incloses the articulation of the inferior cornu of the
thyroid with the cricoid cartilage on each side. The articulation is lined by
synovial membrane.
The ligaments connecting the arytenoid cartilages to the cricoid are two thin
and loose capsular ligaments connecting together the articulating surfaces,
lined internally by synovial membrane, and strengthened behind by a strong
posterior crico-arytenoid ligament, which extends from the cricoid to the inner
and back part of the base of the arytenoid cartilage.
The ligaments of the epiglottis are the hyo- epiglottic, the thyro-epiglottic,
and the three glosso-epiglottic folds of mucous membrane which connect the
epiglottis to the sides and base
467. — The Larynx and adjacent parts,
seen from above.
Arytinoid. cart
of the tonsfue. The latter
have been already described.
The hyo -epiglottic ligament is
an elastic fibrous band, which
extends from the anterior sur-
face of the epiglottis, near its
apex, to the posterior surface
of the body of the hyoid bone.
The thyro-e-piglottic ligament
is a long, slender, elastic cord,
which connects the apex of the
epiglottis with the receding
angle of the thyroid cartilage,
immediately beneath the me-
dian notch, above the attach-
ment of the vocal cords.
Interior of the Larynx. The
superior aperture of the larynx
(Fig. 467) is a triangular or
cordiform opening, wide in
front, narrow behind, and slop-
ing obliquely downwards and backwards
epiglottis ; behind, by the apices of the arytenoid cartilages, and the cornicula
laryngis ; and laterally, by a fold of mucous membrane, inclosing ligamentous
and muscular fibres, stretched between the sides of the epiglottis and the apex
52
It is bounded in front by the
818
ORGANS OF VOICE AND RESPIRATION.
Fig. 468.— Vertical Section of the
Larynx aud Upper Part of the Trachea.
of the arytenoid cartilages: tliese are tlie aryteno-epiglottidean folds, on tlie
margins of which, the cuneiform cartilages form a more or less distinct whitish
prominence.
The cavity of the larynx extends from the aperture behind the epiglottis to
the lower border of the cricoid cartilage. It is divided into two parts by the
projection inwards of the vocal cords and the Thyrorarytenoid muscles; between
the two cords is a long and narrow triangular fissure or chink, the glottis or rima
glottidis. The portion of the cavity of the larynx above the glottis is broad and
triangular in shape above, and corresponds to the interval between the alse of
the thyroid cartilage ; the portion below the glottis is at first of an elliptical,
and lower down of a circular form.
The glottis (rima glottidis) is the interval between the inferior or true vocal
cords. The two superior or false vocal cords are placed above the latter, and
are formed almost entirely by a folding in-
wards of the mucous membrane ; whilst the
two inferior or true vocal cords are thick,
strong, and formed partly by mucous mem-
brane, and partly by ligamentous fibres.
Between the true and false vocal cords, on
each side, is an oval depression, the sinus, or
ventricle of the larynx,, which leads upwards
on the outer side of the superior vocal cord,
into a csecal pouch of variable size, the
sacculus laryngis.
The rima glottidis is a narrow fissure or
chink between the inferior or true vocal
cords. It is the narrowest part of the
cavity of the larynx, and corresponds to thB
lower level of the arytenoid cartilages. Its
length, in the male, measures rather less
than an inch, its breadth, Avhen dilated,
varying at its widest part from a third to
half an inch. In the female, these measure-
ments are less by two or three lines. The
form of the glottis varies. In its half closed
condition it is a narrow fissure, a little
enlarged and rounded behind. In quiet
breathing it is widely open, somewhat tri-
angular, the base of the triangle directed
backwards, and corresponding to the space
between the separated arytenoid cartilages.
In forcible expiration it is vSmaller than
during inspiration. "When sound is produced, it is more narrowed, the margins
of the arytenoid cartilages being brought into contact, and the edges of the vocal
cords approximated and made parallel, the degree of approximation and tension
corresponding to the height of the note produced.^
The superior or false vocal cords^ so called because they arc not directly con-
cerned in tlie production of the voice, are two folds of mucous membrane,
inclosing a delicate narrow fibrous band, the superior thyro-arytenoid ligament.
This ligament consists of a thin band of clastic tissue, attached in front to the
angle of the thyroid cartilage below the epiglottis, and behind to the anterior
surface of the arytenoid cartilage. The lower border of this ligament, inclosed
in mucous membrane, forms a free crescentio margin, which constitutes the
upper boundary of the ventricle of the larynx.
rjlenoil
call..'
lyUno
' On ll'.f sliapf of the frlotfis, in llio various conditions of broathinir and speaking, sec " Cz3r-
iiialv on the Laryngoscope," traiishitcd fur tlie New Sydenham, Socidi/.
MUSCLES OF LARYNX. 819
Tlie inferior or true vocal cords, so called from their being concerned in the
production of sound, are two strong fibrous bands (inferior thyro-arytenoid liga-
ments), covered on their surface by a thin layer of mucous membrane. Each
ligament consists of a band of yellow elastic tissue, attached in front to the de-
pression between the two alse of the thyroid cartilage, and behind to the anterior
■ angle of the base of the arytenoid. Its lower border is continuous with the thin
lateral part of the crico- thyroid membrane. Its upper border forms the lower
boundary of the ventricle of the larynx. Externally, the Thyro-arytasnoideus
muscle lies parallel with it. It is covered internally by mucous membrane, which
is extremely thin, and closely adherent to its surface.
The ventricle of the larynx is an oblong fossa, situated between the superior
and inferior vocal cords on each side, and extending nearly their entire length.
This fossa is bounded above by the free crescentic edge of the superior vocal
cord ; below by the straight margin of the true vocal cord ; externally, by the
corresponding Thyro-arytsenoideus muscle. The anterior part of the ventricle
leads up by a narrow opening into a caecal pouch of mu.cous membrane of vari-
able size, called the laryngeal pouch.
The sacculus laryngis, or laryngeal pouch, is a membranous sac placed between
the superior vocal cord and the inner surface of the thyroid cartilage, occasion-
ally extending as far as its upper border ; it is conical in form, and curved
slightly backwards, like a Phrygian cap. On the surface of its mucous mem-
brane are the openings of sixty or seventy small follicular glands, which are
lodged in the submucous areolar tissue. This sac is inclosed in a fibrous capsule
continuous below with the superior thyro-arytenoid ligament: its laryngeal
surface is covered by the Aryteeno-epiglottideus inferior muscle (^Compressor
sacculi laryngis, Hilton) ; whilst its exterior is cover.ed by the Thyro-epiglotti-
deus muscle. These muscles compress the sacculus laryngis, and discharge the
secretion it contains upon the chordae vocales, the surface of which it is intended
to lubricate.
Muscles. The intrinsic muscles of the larynx are eight in number; five of
which are the muscles of the chordee vocales and rima glottidis ; three are con-
nected with the epiglottis.
The five muscles of the chords vocales 'and rima glottidis are the
Crico-thyroid. Arytsenoideus.
Crico-arytsenoideus posticus. Thyro-arytsenoideus.
Crico-aryt^noideus lateralis.
The Crico-thyroid is triangular in form, and situated at the fore part and side
of the cricoid cartilage. It arises from the front and lateral part of the cricoid
cartilage ; its fibres diverge, passing obliquely upwards and outwards, to be in-
serted into the lower and inner borders of the thyroid cartilage, from near the
median line in front, as far back as the inferior cornu.
The inner borders of these two muscles are separated in the middle line by a
triangular interval, occupied by the crico-thyroid membrane.
The Crico-arytsenoideiis posticus arises from the broad depression occupying
each lateral half of the posterior surface of the cricoid cartilage ; its fibres pass
upwards and outwards, converging to be inserted into the outer angle of the
base of the arytenoid cartilage. The upper fibres are nearly horizontal, the
middle oblique, and the lower almost vertical.^
' Dr. Merkel of Liepsic has described a muscular slip which occasionally extends between the
outer border of the posterior surface of the cricoid cartilage and the posterior margin of the infe-
rior cornu of the thyroid ; this he calls the " Muscnlus kerato-cricoideus." It is not found in
every larynx, and when present exists usually only on one side, but is occasionally found on both
sides. Mr. Turner {Edinburgh 3Iedical Journal, Feb. 1860) states that it is' found in about
one case in tive. Its action is to fix the lower horn of the thyroid cartilage backwards and down-
wards, opposing in some measure the part of the Crico-thyroid muscle which is connected to the
anterior margin of the horn.
820
ORGANS OF VOICE AND RESPIRATION.
Fig-. 469.— Muscles of Larynx. Side View.
Right Ala of Thyroid Cartilage removed.
Comiru ^1,,^
ArtUulav facet
forli^rior Cor'nu
Fig. 470.— Interior of the Larynx, seen
from above. (Enlarged. )
Tlio muscles of the epiglottis are, the
Tliyro-cpiglotUdcns.
Arvt;cno-c])i,<rlottid(!ns superior.
Arytieno-epiglottidens iulerior.
The Crico - arytsenoideus lateralis is
smaller than the preceding, and of an
oblong form. It arises from the upper
border of the side of the cricoid cartilage,
and, passing obliquely upwards and
backwards, is inserted into the outer an-
gle of the base of the arytenoid cartilage,
in front of the preceding muscle.
The Thif)'o-aryt8enoideus is a broad,
flat muscle, which lies parallel with the
outer side of the true vocal cord. It
arises in front from the lower half of the
receding angle of the thyroid cartilage,
and from the crico-thyroid membrane.
Its fibres pass horizontally backwards
and outwards, to be inserted into the
base and anterior surface of the aryte-
noid cartilage. This muscle consists of
two fasciculi. The inferior^ the thicker,
is inserted into the anterior angle of the
base of the arytenoid cartilage, and into
the adjacent portion of its anterior sur-
face ; it lies parallel with the true vocal
cord, to which it is occavsionally adherent.
The superior fasciculus, the thinner, is
inserted into the anterior surface and
outer border of the arytenoid cartilage
above the preceding fibres ; it lies on the
outer side of the sacculus laryngis, imme-
diately beneath its mucous lining.
The Arytsenoideus is a single muscle,
filling up the posterior concave surface
of the arytenoid cartilages. It arises
from the posterior surface and outer bor-
der of one arytenoid cartilage, and is
inserted into the corresponding parts of
the opposite cartilage. It consists of
three planes of fibres: two oblique and
one transverse. The ohlique fhres, the
most superficial, form two fasciculi, which
pass from the base of one cartilage to
the apex of the opposite one. The trans-
verse Jihres, the deepest and most nume-
rous, pass transversely across between
the two cartilages ; hence the Arytamoi-
deus was formerly considered as several
muscles, under the name of transversi and
ohliqui. A few of the oblique fibres are
occasionally continued round the outer
margin of the cartilage, and blend with
the Tliyro- arytenoid or the Aryta3no-
cpiglottideus muscle.
MUSCLES OF LARYNX. 821
The Thyro-eipujlottideus is a delicate fasciculus, whicli arises from the inner
surface of the thyroid cartilage, just external to the origin of the Thyro-aryte-
noid muscle, and spreading out upon the outer surface of the sacculus laryngis,
some of its fibres are lost in the aryteno-epiglottidean fold, whilst others are
continued forwards to the margin of the epiglottis {De'pressor epiglottidis).
The Arytseyio-epiglottideus superior consists of a few delicate muscular fasciculi,
which arise from the apex of the arytenoid cartilage, and become lost in the
fold of mucous membrane extending between the arytenoid cartilage and side
of the epiglottis {aryteno-glottidean folds).
The Arytseno-epiglottideus inferior [Compressor sacculi laryngis^ Hilton) arises
from the arytenoid cartilage, just above the attachment of the superior vocal
cord ; passing forwards and upwards, it spreads out upon the inner and upper
part of the sacculus laryngis, and is inserted, by a broad attachment, into the
margin of the epiglottis. This muscle is separated from the preceding by an
indistinct areolar interval.'
Actions. In considering the action of the muscles of the larynx, they may be
conveniently divided into two groups, viz.: 1. Those which open and close the
glottis. 2, Those which regulate the degree of tension of the vocal cords.
1. The muscles which open the glottis are the Crico-arytsenoidei postici; and
those which close it are the Arytsenoideus and the Crico-arytsenoidei laterales.
2. The muscles which regulate the tension of the vocal cords are, the Crico-thy-
roidei, which tense and elongate them ; and the Thyro-aryteenoidei, which relax
and shorten them. The Thyro-epiglottideus is a depressor of the epiglottis, and
the Arytseno-epiglottidei constrict the superior aperture of the larynx, compress
the sacculi laryngis, and empty them of their contents.
The Crico-arytcenoidei postzci separate the chordsB vocales, and, consequently, open the
glottis, by rotating the base of the arytenoid cartilages outwards and backwards; so that their
anterior angles and the ligaments attached to them become widely separated, the vocal cords, at
the same time, being made tense.
The Crico-arytcenoidei laterales close the glottis, by rotating the base of the arytenoid carti-
lages inwards, so as to approximate their anterior angles.
The Ar ytcenoideus muscle approximates the arytenoid cartilages, and thus closes the opening
of the glottis, especially at its back part.
TJie Crico-thyroid muscles produce tension and elongation of the vocal cords, by drawing
down the thyroid cartilage over the cricoid.
The Thyro-arytcenoidei muscles draw the arytenoid cartilages, together with the part of the
cricoid to which they are connected, forwards towards the thyroid, and thus shorten and relax the
vocal cords.
The Thyro-epiglottidei depress the epiglottis, and assist in compressing the sacculi laryngis.
The Arytaeno-epiglottideus superior constricts the superior aperture of the larynx, when it is
drawn upwards, during deglutition, and the opening closed by the epiglottis. The Arytseno-epi-
glottideus inferior, together with some fibres of the Thyro-arytaenoidei, compress the sacculus
laryngis.
The Mucous Memhrane of the larynx is continuous above with that lining the
mouth and pharynx, and is prolonged through the trachea and bronchi into the
lungs. It lines both surfaces of the epiglottis, to which it is closely adherent,
and forms the aryteno-epiglottidean folds which encircle the superior aperture
of the larynx. It lines the whole of the cavity of the larynx ; forms, by its
reduplication, the chief part of the superior, or false, vocal cord ; and, from the
ventricle, is continued into the sacculus laryngis. It is then reflected over the
true vocal cords, where it is thin, and very intimately adherent; covers the
inner surface of the crico-thyroid membrane and cricoid cartilage ; and is ulti-
mately continuous with the lining membrane of the trachea. It is covered with
columnar ciliated epithelium, below the superior vocal cord ; but above this
' MuscuLus TRiTicEO-GLOssus. Bochdalek junr. {Prager Vierteljahrschrift, 2d Part, 1866)
describes a muscle hitherto entirely overlooked, except a brief statement in Henle's "Anatomy,"
■which arises from the nodule of cartilage (corpus triticeum) in the posterior thyro-hyoid ligament,
and passes forwards and upwards to enter the tongue along with the Kerato-glossus muscle. He
met with this muscle eight times in twenty-two subjects. It occurred in both sexes, sometimes on
both sides, at others on one only.
822
ORGANS OF VOICE AND RESPIRATION.
point, the cilia are found only in front, as high as the middle of the epiglottis.
In the rest of its extent, the epithelium is of the squamous variety.
Olands. The mucous membrane of the larynx is furnished with numerous
muciparous glands, the orifices of which are found in nearly every part ; they
are very numerous upon the epiglottis, being lodged in little pits in its substance ;
they are also found in large numbers along the posterior margin of the aryteno-
epiglottidean fold, in front of the arytenoid cartilages, where they are termed the
arytenoid glands. They exist also in large numbers upon the inner surface of
the sacculus laryngis. None are found on the vocal cords.
"Vessels and Nerves. The arteries of the larynx are the laryngeal branches
derived from the superior and inferior thyroid. The veins empty themselves
Fig. 471. — Front Yiew of Cartilages of Larynx : the Trachea and Bronchial.
into the superior middle and inferior thyroid veins. The lymphatics terminate
in the deep cervical glands. The nerves are the superior larjaigeal, and the
inferior or recurrent laryngeal branches of the pneumogastric nerves, joined by
filaments from the syin])atlietic. The superior laryngeal nerves sup])ly the
mucous membrane of tlic larynx and the Crico-tliyroid muscles. The inferior
TRACHEA.
8-23
laryngeal nerves supply the remaining muscles. The Arytenoid muscle is
supplied by both nerves.
The Trachea. (Fig. 471.)
The Trachea, or air-tube, is a cartilaginous and membranous cylindrical tube
flattened posteriorly, which extends from the lower part of the larynx, on a level
with the fifth cervical vertebra, to opposite the third dorsal, where it divides
into the two bronchi, one for each lung. The trachea, measures about four
inches and a half in length; its diameter, from side to side, is from three-
quarters of an inch to an inch, being always greater in the male than in the
female.
Relations. The anterior surface of the trachea is convex, and covered in the
neck, from above downwards, by the isthmus of the thyroid gland, the inferior
thyroid veins, the arteria thyroidea ima (when that vessel exists), the Sterno-
hyoid and Sterno-thyroid muscles, the cervical fascia (in the interval between
those muscles), and, more superficially, by the anastomosing branches between
the anterior jugular veins; in the thorax, it is covered from before backwards by
the first piece of the sternum, the remains of the thymus gland, the arch of the
aorta, the innominate and left carotid arteries, and the deep cardiac plexus. It
lies upon the oesophagus, which is directed to the left near the arch of the aorta ;
laterally, in the neck, it is in relation with the common carotid arteries, the lateral
lobes of the thyroid gland, the inferior thyroid arteries, and recurrent laryngeal
nerves: and, in the thorax, it lies in the interspace between the pleurae, having
the pneumogastric nerve on each side of it.
The Bight Bronchus, wider, shorter, and more horizontal in direction than the
left, is about an inch in length, and enters the right lung, opposite the fourth
dorsal vertebra. The vena azygos
Fig'. 472. — Transverse Section of the Trachea,
just above its Bifurcation, with a bird's eye
view of the interior.
Zff^
R^S^i-
arches over it, from behind; and the
right pulmonary artery lies below, and
then in front of it.
The Left Bronchus is smaller, more
oblique, and longer than the right, being
nearly two inches in length. It enters
the root of the left lung, opposite the
fifth dorsal vertebra, about an inch
lower than the right bronchus. It
crosses, in front of the oesophagus, the
thoracic duct, and the descending aorta ;
passes beneath the arch of the aorta,
and has the left pulmonary artery lying at first above, and then in front of it.
If a transverse section is made across the trachea, a short distance above its
point of bifurcation, and a bird's eye view taken of its interior (Fig. 472), the
septum placed at the bottom of the trachea and separating the two bronchi will
be seen to occupy the left of the median line, as was first shown by Mr. Goodall,
of Dublin, so that any solid body dropping into the trachea would naturally be
directed towards the right bronchus, and this tendency is undoubtedly aided by
the larger size of this tube, as compared with its fellow. This fact serves to
explain why a foreign substance in the trachea generally falls into the right
bronchus.
The trachea is composed of imperfect cartilaginous rings, fibrous membrane,
muscular fibres, longitudinal yellow elastic fibres, mucous membrane, and glands.
The Cartilages vary from sixteen to twenty in number: each forms an im-
perfect ring, which surrounds about two-thirds of the cylinder of the trachea,
being imperfect behind, where the tube is completed by fibrous membrane. The
cartilages are placed horizontally above each other, separated by narrow mem-
branous intervals. They measure about two lines in depth, and half a line in
824 ORGANS OF VOICE AND RESPIRATION.
thickness. Their outer surfaces are flattened, but, internally, they are convex,
from being thicker in the middle than at the margins. The cartilages are con-
nected together, at their margins, by an elastic fibrous membrane, which covers
both their surfaces; and in the space between their extremities, behind, forms
a distinct layer. The peculiar cartilages are the first and the last.
The first cartilage i^ broader than the rest, and sometimes divided at one end;
it is connected by fibrous membrane with the lower border of the cricoid carti-
lage, with which, or with the succeeding cartilage, it is sometimes blended.
The last cartilage is thick and broad in the middle, in consequence of its lower
border being prolonged downwards, and, at the same time, curved backwards,
at the point of bifurcation of the trachea. It terminates on each side in an
imperfect ring, which incloses the commencement of the bronchi. The cartilage
above the last is somewhat broader than the rest at its centre. Two or more
of the cartilages often unite, partially or completely, and are sometimes bifur-
cated at their extremities. They are highly elastic, and seldom ossify, even in
advanced life. In the right bronchus the cartilages vary in number from six
to eight; in the left, from nine to twelve. They are shorter and narrower than
those of the trachea.
The Muscular Fibres are disposed in two layers, longitudinal and transverse.
The longitudinal fibres are the most external, and arise by minute tendons from
the termination of the tracheal cartilages, and from the fibrous membrane.
The Transverse Fibres (Trachealis muscle, Todd and Bowman), the most
internal, form a thin layer, which extends transversely between the ends of the
cartilages at the posterior part of the trachea. The muscular fibres are of the
unstriped variety.
The Elastic Fibres are situated beneath the mucous membrane, inclosing the
entire cylinder of the trachea ; they are most abundant at its posterior part,
where they are collected into longitudinal bundles.
The Mucous Membrane lining the tube is covered with columnar ciliated epi-
thelium. It is continuous above with that of the larynx, and below with that
of the lungs.
The Tracheal Glands are found in great abundance at the posterior part of
the trachea. They are small, flattened, ovoid bodies, placed between the fibrous
and muscular coats, each furnished with an excretory duct, which opens on the
surface of the mucous membrane. Some glands of smaller size are also found
at the sides of the trachea, between the layers of fibrous tissue connecting the
rings, and others immediately beneath the mucous coat. The secretion from
these glands serves to lubricate the inner surface of the trachea.
Vessels and Nerves. The trachea is supplied with blood by the inferior thyroid
arteries. The veins terminate in the thyroid venous plexus. The nerves are
derived from the pneumogastric and its recurrent branches, and from the sym-
pathetic.
Surgical Anatomy. The air-passafjcs may be opened in three different situations: thronc:h
the crico-lhyroid membrane [laryngotomy), tlirough llie cricoid cartilage and npper rin<r of the
trachea [laryngo-trarJieotoniy], or through the trachea below the isthnnis of the thyroid gland
[tracheotomy). The student should, therefore, carefully consider the relative anatomy of the
air-lube in each of these situations.
]5(Mieath the integument of the laryngo tracheal region, on either side of the median line, are
the two anterior jugnhir veins. 'I'heir size and jiosition vary; there is nearly always one, and
fre(|uently two; at the lower part of the neck they diverge. ])assing beneath tlie Slerno-masloid
museleH, and are frefjuently connected by a transverse counnunicating branch. 'I'hese veins
should, if ]iossii)le, always l)e avoided in any operation on the larynx or tracliea. If cut through,
considerable hemorrhage occurs.
Beneath the cervical fascia are the Hterno-hyoid and Sterno-lhyroid muscles, the contiguous
edges of the former being near the median line; and l)enea1h these muscles the following parts
are m(!t with, from above downwards: the thyroid cartilag(% the cricothyroid membrane, the
cricoid cartilage, tiic trachea, and the isthmus of the thyroi(i glaiul.
'l'li(! crico-thyroid sptice is very superficial, and may lie easily felt ben(>uth the skin as a depres-
sion abfiut an inch below the poniurn Adami : it is crossed transversely by a small artery, the
crico-thyroid, the division of which is seldom accompanied by any troublesome hemorrhage.
SURGICAL ANATOMY OF LARYNX AND TRACHEA. 825
The isthmus of the thyroid gland usually crosses the second and third rings of the trachea ;
above it is found a large transverse communicating branch between the superior thyroid veins,
and the isthmus is covered by a venous plexus, formed between the thyroid veins of opposite sides.
On the sides of the thyroid gland, and below it, the veins converge to a single median vessel, or
to two trunks which descend along the median line of the front of the trachea, to open into the
innominate veins by valved orifices. In the infant, the thymus gland ascends a variable distance
along the front of the trachea ; and the innominate artery crosses the tube obliquely at the root
of the neck, from left to right. The arteria thyroidea ima, when that vessel exists, passes from
below upwards along the front of the trachea. The upper part of the trachea lies comparatively
superficial; but the lower part passes obliquely downwards and backwards, so as to be deeply
placed between the converging Sterno-mastoid muscles. In the child, the trachea is smaller,
more deeply placed, and more movable than in the adult. In fat or short-necked people, or in
those in whom the muscles of the neck are prominently developed, the trachea is more deeply
placed than in the opposite conditions.
Fig. 473. — Surgical Anatomy of Laryngo-tracheal Region.
In the Infant.
Cfioo-tKyroul Mxrfnbra7i£
&t Artery
From these observations, it must be evident that laryngotomy is anatomically the most simple
operation, can most readily be performed, and should always be preferred, when particular circum-
stances do not render the operation of tracheotomy absolutely necessary. The operation is per-
formed thus: The head being thrown back and steadied by an assistant, the finger is passed over
the front of the neck, and the crico-thyroid depression felt for. A vertical incision is then made
through the skin, in the middle line over this spot, and the cricothyroid membrane is divided to
a sufficient extent to allow of the introduction of a large curved tube. The crico thyroid artery
is the only vessel of importance crossing this space. If it should be of large size, its division might
produce troublesome hemorrhage.
Laryngo-tracTientomy, anatomically considered, is more dangerous than tracheotomy, on
account of the small interspace between the cricoid cartilage and the isthmus of the thyroid gland :
the communicating branches between the superior thyroid veins, which cover this spot, can hardly
fail to be divided ; and the greatest care will not. in some cases, prevent the division of part of
the thyroid isthmus. If either of these structures is divided, the hemorrhage may be considerable.
Tracheotomy below the isthmus of the thyroid g^land is performed thus : The head being thrown
back and steadied by an assistant, an incision, an inch and a half or two inches in length, is made
through the skin in the median line of the neck, from a little below the cricoid cartilage to the
top of the sternum. The anterior jugular veins should be avoided, by keeping exactly in the
median line ; the deep fascia should then be divided, and the contiguous borders of the Sterno-
hyoid muscles separated from each other. A quantity of loose areolar tissue, containing the infe-
rior thyroid veins, must then be separated from the front of the trachea, with the handle of the
scalpel ; and when the trachea is well exposed, it should be opened by inserting the knife into it,
dividing two or three of its rings from below upwards. It is a matter of the greatest importance
to restrain, if possible, all hemorrhage before the tube is opened ; otherwise, blood may pass into
the trachea, and suffocate the patient.
826
ORGANS OF VOICE AND RESPIRATION.
The Pleura.
Each, lung is invested, upon its external surface, by an exceedingly delicate
serous membrane, the Pleura, which incloses the organ as far as its root, and is
then reflected upon the inner surface of the thorax. The portion of the serous
membrane investing the surface of the lung is called the pleura pulmonalis
(visceral layer of pleura), while that which lines the inner surface of the chest
is called the pleura costalis (parietal layer of pleura). The interspace or cavity
between these two layers is called the cavity of the pleura. Each pleura is there-
fore a shut sac, one occupying the right, the other the left half of the thorax ;
and they are perfectly separate, not communicating with each other. The two
Fig. 474. — A Transverse Section of the Thorax, showing the relative Position of the Viscera,
and the Eeflection of the Pleura.
TRIAHCL'LAt^tS ETERNI
ItifernulMi n Jir j V ^ ?U
Lifi Phrcnie Kiriie
Pleufa fiutmonaCes
Pleuva Coslalis
^Trt/iaKtmuj.
[ Stj'mpa.thetio N'erve
' Thorn etc Uuct
Vena. Axyao, Mu/or )
Piieumoaasiric Acrres \
pleurae do not meet in the middle line of the chest, excepting at one point in
front ; an interspace being left betAveen them, which contains all the viscera of
the thorax, excepting the lungs: this is the 'mediastinum.
Rejlections of tire pleura (Fig. 474). Commencing at the sternum, the pleura
passes outwards, covers the costal cartilages, the inner surface of the ribs and
intercostal muscles, and at the back part of the thorax passes over the thoracic
ganglia and their branches, and is reflected upon the sides of the bodies of the
vertebra}, where it is separated by a narrow interspace the 'posterior mediastinum
from the opposite pleura. Froni the vertebral column the pleura passes to the
side of the i)cricardium, Avhich it covers to a slight extent; it then covers the
back part of tlic root of the lung, from the lower border of which a triangular
fold descends vertically by the side of the posterior mediastinum to the Dia-
phragm. This fold is the broad ligament of the lung, the ligatnentum latum
pulmonis, and serves to retain the lower part of that organ in position. From
the root, the pleura may be traced over the convex surface of the lung, the
summit and base;, and also over the sides of the fissures betAVcen the lobes: It
covers its anterior surface, and the front part of its root, and is reflected upon
MEDIASTINUM— THE LUNGS. 827
tlie side of the pericardium to tlie inner sarface of the sternum. Below, it
covers the under surface of the Diapliragm. Above, its apex projects, in the
form of a cnl-de-sac, through the superior opening of the thorax into tlie neck,
extending about an inch above the margin of the first rib, and receives the
summit of the corresponding lung ; this sac is strengthened, according to Dr.
Sibson, by a dome-like expansion of fascia, derived from the lower part of the
Scaleni muscles.
A little above the middle of the sternum, the contiguous surfaces of the two
pleurae are sometimes in contact for a slight extent ; but above and below this
point, the interval left between them forms the anterior mediastinum.
The inner surface of the pleura is smooth, polished, and moistened by a serous
fluid; its outer surface is intimately adherent to the surface of the lung, and to
the pulmonary vessels as they emerge from, the pericardium; it is also adherent
to the upper surface of the Diaphragm : throughout the rest of its extent it is
somewhat thicker, and may be separated from the adjacent parts with extreme
facility.
The right pleural sac is shorter, wider, and reaches higher in the neck than
the left.
Vessels and Nerves. The arteries of the pleura are derived from the inter-
costal, the internal mammary, the phrenic, inferior thyroid, thymic, pericardiac,
and bronchial. The veins correspond to the arteries. The lymjDhatics are very
numerous. The nerves are derived from the phrenic and sympathetic (Luschka).
Kolliker states that nerves accompany the ramifications of the bronchial arteries
in the pleura pulmonalis.
Mediastinum.
The Mediastinum is the space left in the median line of the chest by the non-
approximation of the two pleurse. It extends from the sternum in front to the
spine behind, and contains all the viscera in the thorax, excepting the lungs.
The mediastinum is subdivided, for convenience of description, into the anterior,
middle, and posterior.
The anterior mediastinum is bounded in front by the sternum, on each side by
the pleura, and behind by the pericardium. Owing to the oblique position of
the heart towards the left side, this space is not parallel with the sternum, but
directed obliquely from above downwards, and to the left of the median line ; it
is broad below, narrow above, very narrow opposite the second piece of the
sternum, the contiguous surfaces of the two pleurse being occasionally united
over a small space. The anterior mediastinum contains the origins of the Sterno-
hyoid and Sterno-thyroid muscles, the Triangularis sterni, the internal mammary
vessels of the left side, the. remains of the thymus gland, and a quantity of loose
areolar tissue, in which some lymphatic vessels are found ascending from the
convex surface of the liver.
The middle mediastinum is the broadest part of the interpleural space. It con-
tains the heart inclosed in the pericardium, the ascending aorta, the superior
vena cava, the bifurcation of the trachea, the pulmonary arteries and veins, and
the phrenic nerves.
The posterior mediastinum is an irregular triangular space, running parallel
with the vertebral column; it is bounded in front by the pericardium and roots
of the lungs, behind by the vertebral column, and on either side by the pleura.
It contains the descending aorta, the greater and lesser azygos veins and left
superior intercostal vein, the pneumogastric and splanchnic nerves, the oesopha-
gus, thoracic duct, and some lymphatic glands.
The Lungs.
The Lungs are the essential organs of respiration ; they are two in number,
placed one in each of the lateral cavities of the chest, separated from each other
828
ORGANS OF VOICE AND RESPIRATION.
by the heart and other contents of the mediastinum. Each lung is conical in
shape, and presents for examination an apex, a base, two borders, and two sur-
faces (see Fig. 477).
Fis'. 475. — The Posterior Mediastinum. Anterior View.
The apex forms a tappcring cone, which extends into the root of the neck,
about an inch to nn inch and a half above the level of the first rib.
The hase is broad, concave, and rests upon the convex surface of the Dia-
THE LUNGS,
829
pliragm ; its circumference is thin, and fits into tlie space between tlie lower
ribs and tbe costal attacliment of the Diaphragm, extending lower down exter-
nally and behind than in front.
Fig. 476. — The Posterior Mediastiuuni aud Root of the Neck. Posterior View.
THORACIC. 01
The external or thoracic surface is smooth, convex, of considerable extent, and
corresponds to the form of the cavity of the chest, being deeper behind than in
front.
The inner surface is concave. It presents, in front, a depression correspond-
ing to the convex surface of the pericardium, and behind, a deep fissure (the
hilum pulmonis) which gives attachment to the root of the lung.
The posterior border is rounded and broad, and is received in the deep con-
830
ORGANS OF VOICE AND RESPIRATION.
cavity on eitlier side of tlie spinal column. It is mucli longer tlian the anterior
border, and projects below between tbe ribs and the Diaphragm.
The anterior border is thin and sharp, and overlaps the front of the pericar-
dium.
The anterior border of the right lung corresponds to the median line of the
sternum, and is in contact with its fellow, the pleuree being interposed, as low as
the fourth costal cartilage ; below this, the contiguous borders are separated
by an irregularly shaped interval, formed at the expense of the anterior border
of the left lung, and in which the pericardium is exposed.
Each lung is divided into two lobes, an upper and lower, by a long and deep
fissure, which extends from the upper part of the posterior border of the organ,
Fig. 477. — Front View of the Heart and Lungs.
Ductus A rteri asua
about three inches from its apex, downwards and forwards to the lower part of
its anterior border. This fissure penetrates nearly to the root. In the right
lung the upper lobe is partially divided by a second and shorter fissure, which
extends from the middle of the preceding, forwards and upwards, to the anterior
margin of the organ, marking ofi'a small triangular portion, the middle lobe.
The ri(jht hmf/ is tlic larger; it is broader than the left, owing to the inchna-
tion of the heart to the left side; it is also shorter by an inch, in consequence
of the Diaphragm rising higher on the right side to accommodate the liver.
The right lung lias three lobes.
The Ir/i lun'j is smaller, narrower, and longer than the right, and has only
two h)l)eH.
A little above the middle of the inner surface of each lung, and nearer its
posterior than its anterior border, is its root^ by which the lung is connected to
the heart and the trachea. The root is formed by the bronchial tube, the pul-
THE LUNGS. 831
monary artery, the pulmonary veins, the bronchial arteries and veins, the pul-
monary plexus of nerves, lymphatics, bronchial glands, and areolar tissue, all of
which are inclosed by a reflection of the pleura. The root of the right lung
lies behind the superior vena cava and upper part of the right auricle, and below
the vena azygos. That of the left lung passes beneath the arch of the aorta,
and in front of the descending aorta ; the phrenic nerve and the anterior pul-
monary plexus lie in front of each, and the pneumogastric and posterior pulmo-
nary plexus behind each.
The chief structures composing the root of each lung are arranged in a
similar manner from before backwards on both sides, viz. : the pulmonary veins
most anterior; the pulmonary artery in the middle; and the bronchus, together
with the bronchial vessels, behind. From above downwards, on the two sides,
their arrangement differs, thus : —
On the right side, their position is, bronchus, pulmonary artery, pulmonary
veins; but on the left side their position is, pulmonary artery, bronchus, pul-
monary veins ; which is accounted for by the bronchus being placed on a lower
level on the left than on the right side.
The weight of both lungs together is about forty-two ounces, the right lung
being two ounces heavier than the left ; but much variation is met with accord-
ing to the amount of blood or serous fluid they may contain. The lungs are
heavier in the male than in the female, their proportion to the body being, in
the former, as 1 to 37, in the latter as 1 to 43. The specific gravity of the lung-
tissue varies from 345 to 746, water being 1000.
The color of the lungs at birth is a pinkish- white; in adult life, a dark slate-
color, mottled in patches ; and as age advances, this mottling assumes a black
color. The coloring matter consists of granules of a carbonaceous substance
deposited in the areolar tissue near the surface of the organ. It increases in
quantity as age advances, and is more abundant in males than in females. The
posterior border of the lung is usually darker than the anterior. The surface of
the lung is smooth, shining, and marked out into numerous polyhedral spaces,
indicating the lobules of the organ : the area of each of these spaces is crossed
by numerous lighter lines.
The substance of the lung is of a light, porous, spongy texture ; it floats in
water, and crepitates when handled, owing to the presence of air in the tissue ;
it is also highly elastic ; hence the collapsed state of these organs when they are
removed from the closed cavity of the thorax.
Structure. The lungs are composed of an external serous coat, a subserous
areolar tissue, and the pulmonary substance or parenchyma.
The serous coat is derived from the pleura ; it is thin, transparent, and invests
the entire organ as far as the root.
The subserous areolar tissue contains a large proportion of elastic fibres ; it
invests the entire surface of the lung, and extends inwards between the lobules.
The parenchyma is composed of lobules, which, although closely connected
together by an interlobular areolar tissue, are quite distinct from one another,
and are easily separable in the foetus. The lobules vary in size ; those on the
surface are large, of a pyramidal form, the base turned towards the surface ;
those in the interior smaller, and of various forms. Each lobule is composed of
one of the ramifications of the bronchial tube and its terminal air-cells, and of
the ramifications of the pulmonary and bronchial vessels, lymphatics, and
nerves: all of these structures being connected together by areolar fibrous
tissue.
The bronchiis^ upon entering the substance of the lung, divides and subdivides
dichotomously throughout the entire organ. Sometimes three branches arise
together, and occasionally small lateral branches are given off from the sides of
a main trunk. Each of the smaller subdivisions of the bronchi enters a pulmo-
nary lobule (lobular bronchial tube), and, again subdividing, ultimately termi-
nates in the intercellular passages and air-cells of which the lobule is composed.
832
ORGANS OF VOICE AND EESPIRATION.
Within the lungs the bronchial tubes are circular, not flattened, and their con-
stituent elements present the following peculiarities of structure.
Fig. 478.— The Roots of the Lungs aud Posterior Pulmonary Plexus, seen from Behind.
The cartUarjes are not imperfect rings, but consist of thin laminas, of varied
form and size, scattered irregularly along the sides of the tube, being most dis-
tinct at the ]:)oints of division of the bronchi. They may be traced into tubes,
the diameter of which is only one-fourth of a line. Beyond this point, the tubes
are wholly membranous. The fibrous coat and the longitudinal elastic fibres
are pontimmd into the smallest ramifications of the bronchi. The muscular coat
is disposed in ilic fonii of a continuous layer of annular fibres, which may be
traced upon llu; smallest bronchial tubes: tliey consist of the unstrijied variety
of musculiir fibre. The mucf)ns membrane lines the bronchi and its ramifica-
tions throughout, ;ind is covered with columnar cillaled (>pithcliiiin.
I
THE LUNGS. 833
According to the observations of Mr. Eainej,' tlie lobular bronchial tubes, on
entering the substance of the lobules, divide and subdivide from four to nine
times, according to the size of the lobule, continuing to diminish in size until
they attain a diameter of -g^ to g'^-th of an inch. They then become changed in
structure, losing their cylindrical form, and are continued onwards as irregular
passages (intercellular passages, Rainey — air-sacs. Waters), through the sub-
stance of the lobule, their sides and extremities being closely covered by nume-
rous saccular dilatations, the air-cells. This arrangement resembles most closely
the naked-eye appearances observed in the reticulated structure of the lung of
the tortoise, and other reptilia. Opinions have differed as to the existence of
communications or anastomoses between the intercellular passages, or air-sacs.
According to Dr. Waters,^ these air-sacs, as he terms them, are arranged in
groups, or "lobulettes," of five or six, which spring from the terminal dilatation
of a single bronchial tube, but have no other communication with each other,
or with neighboring lobulettes, than that which is afforded by their common
connection with the bronchial tubes.
The air-cells, or alveoli (AYaters), are small, polyhedral, alveolar recesses,
separated from each other by thin septa, and communicating freely with the
intercellular passages or air-sacs. They are well seen on the surface of the lung,
and vary from ^^gth to ^V^^^i of ^ii ii^ch in diameter; being largest on the
surface, at the thin borders, and at the apex ; and smallest in the interior.
At the termination of the bronchial tubes, in the intercellular passages, their
constituent elements become changed : their walls are formed by an interlacing
of the longitudinal elastic bundles with fibrous tissue; the muscular fibres
disappear, and the mucous membrane becomes thin and delicate, and lined with
a layer of squamous epithelium. The latter membrane lines the air-cells, and
forms by its reduplications the septa intervening between them.
The Pulmonary Artery conveys the venous blood to the lungs : it divides into
branches which accompany the bronchial tubes, and terminates in a dense capil-
lary network, upon the walls of the intercellular passages and air-cells. From
this network, the radicles of the pulmonary veins arise ; coalescing into large
branches, they accompany the arteries, and return the blood, purified by its
passage through the capillaries, to the left auricle of the heart. In the lung,
the branches of the pulmonary artery are usually above and in front of a
bronchial tube, the vein below.
The Pulmonary Capillaries form plexuses which lie immediately beneath the
mucous membrane, on the walls and septa of the air-cells, and upon the walls
of the intercellular passages. In the se];)ta between the cells, the capillary
network forms a single layer. The capillaries form a very minute network, the
meshes of which are smaller than the vessels themselves ;^ their walls are also
exceedingly thin. The vessels of neighboring lobules are distinct from each
other, and do not anastomose; and, according to Dr, Waters, those of the
separate groups of intercellular passages, or air- sacs (which groups he denomi-
nates lobulettes), are also independent; so that in the septa between two ad-
joining lobulettes, there would be a double layer of capillaries, one layer
belonging to each of the adjacent air-sacs, or intercellular passages. If this is
really the arrangement of the vessels, it would follow that, in the septa between
the air-cells (or alveoli), the blood in the capillaries would be exposed on all
sides to the action of the air, since it is circulating in a single layer of vessels,
which is in contact with the membrane of the air-passages on both sides: but
that, in the septa between the intercellular passages (or air-sacs) the blood in
the double layer of capillaries will be in contact with the air on one side only.
' Medico- Chirurgical Transactions, vol. xxviii., 1845.
^ ''The Anatomy of the Human Lung" 1860, pp. 136-150.
3 The meshes are only 0.002'" to 0.008'" in width, while the vessels are 0.003'" to 0.005'".
KoUiker, Human Microscopic Anatomy.
53
834 ORGANS OF VOICE AND RESPIRATION.
The Bronchial Arteries supply blood for the nutrition of tlie lung : tliey are
derived from the thoracic aorta, and accompanying the bronchial tubes, are
distributed to the bronchial glands, and upon the walls of the larger bronchial
tubes and pulmonary vessels, and terminate in the deep bronchial veins. Others
are distributed in the interlobular areolar tissue, and terminate partly in the
deep, partly in the superficial, bronchial veins. Lastly, some ramify upon the
walls of the smallest bronchial tubes, and terminate in the pulmonary veins.
The Superficial and Deep Bronchial Veins unite at the root of the lung, and
terminate on the right side in the vena azj^gos; on the left side, in the superior
intercostal vein.
According to Dr. Waters, the bronchial veins do not exist within the proper
substance of the lung, but commence at or near the root of the lung, by branches
w^hich lie on the large bronchial tubes. He also denies that the bronchial arteries
contribute to the formation of the pulmonary plexus, believing that the com-
munication between the bronchial and pulmonary system of vessels takes place
in the pulmonary veins. If this view be correct, almost the whole of the blood
carried b}^ the bronchial arteries must be returned to the heart by the pulmo-
nary veins, and thus the great mass of pure, or arterial, blood which is carried
by the pulmonary veins would be adulterated by a small quantity of carbonized
or venous blood which has passed through the bronchial circulation.
The Lymphatics consist of a superficial and deep set : they terminate at the
root of the lung, in the bronchial glands.
Nerves. The lungs are supplied from the anterior and posterior pulmonary
plexuses, formed chiefly by branches from the sympathetic and pneumogastric.
The filaments from these plexuses accompany the bronchial tubes, upon which
they are lost. Small ganglia are found upon these nerves.
Thyroid Gland.
The Thyroid Gland bears much resemblance in structure to other glandular
organs, and is usually classified together with the thymus, supra-renal capsules,
and spleen, under the head of ductless glands^ since it has no excretory duct.
Its function is unknown, but, from its situation in connection with the trachea
and larynx, the thyroid body is usually described with those organs, although
it takes no part in the function of respiration. It is situated at the upper part
of the trachea, and consists of two lateral lobes, placed one on each side of that
tube, and connected together by a narrow transverse portion, the isthmus.
Its anterior surface is convex, and covered by the Sterno-hyoid, Sterno-thyroid,
and Omo-hyoid muscles.
Its lateral surfaces^ also convex, lie in contact with the sheath of the common
carotid artery.
Its T^os/Ierior .swr/ace is concave, and embraces the trachea and larynx. The
posterior borders of the gland extend as far back as the lower part of the
pharjmx.
The thyroid is of a brownish-red color. Its weight varies from one to two
ounces. It is larger in females than in males, and becomes slightly increased
in size during menstruation. It occasionally becomes enormously hypertrophied,
constituting the disease called bronchocele, or goitre. Eacli lobe is somewhat
conical in shape, about two inches in length, and three-quarters of an inch in
breadth, the right lobe being the larger of the two.
The isthmus connects the lower third of the two lateral lobes; it measures
about half an inch in breadth, and the same in depth, and usually covers the
second and tlrird rings of the trachea. Its situation presents, however, many
variations, a point of importance in the operation of tracheotomy. Sometimes
the isthmus is altogether wanting.
A third lobe, of conical sliape, called lh(> pyramid^ occasionally arises from
the left side of the iqipcr part of the isthmus, or i'rom tlie left lobe, and ascends
THYROID GLAND,
835
Fig. 479. — Two lobules from the thyroid
of an infant.
>^ 5^
as liigli as tlie liyoid bone. It is occasionally quite detaclied, or divided into
two parts, or altogether wanting.
A few muscular bands are occasionally found attached, above, to tlie body of
the hyoid bone, and below, to the isthmus of the gland, or its pyramidal process.
These form a muscle, which was named by Sommerring the Levator glandulce
thyroidese.
Structure. The thyroid consists of numerous minute closed vesicles, com-
posed of a homogeneous membrane, inclosed in a dense capillary plexus, and
connected together into imperfect lobules, by areolar tissue. These vesicles
are spherical or oblong, perfectly distinct, and contain a yelloAvish fluid, in
which are found floating numerous "dotted corpuscles" and cells. The fluid
coagulates by heat or alcohol, but preserves its transparency. In the foetus, and
in young subjects, the corpuscles lie in a single layer, in contact with the inner
surface of these cavities, and become detached during the process of growth.
The individual vesicles are inclosed in a vascular connective tissue by means of
which they are packed together into lobules, the aggregation of which forms the
lobes of the gland. In the foetal state, these vesicles are lined by a layer of
small cylindrical epithelial cells, the cavity being filled with a finely granular
substance. Early in life commences, according to Frey, a colloid transformation
by which the cells of the epithelium are separated from the lining of the vesicle,
their nuclei become free and their contents are converted into a colloid, or gluey
matter. It is the excessive increase of this colloid matter which, according to
this author, constitutes the essential phenomenon in the disease above alluded
to as bronohocele or goitre, but its occur-
rence to some extent he regards as normal.
The epithelial cells of the vesicles are
supported on a basement membrane, and in
the cellular tissue external to this are found
the terminations of the small vessels, and
the commencement of the lymphatic chan-
nels.
Vessels and Nerves. The arteries supply-
ing the thyroid are the superior and inferior
thyroid, and sometimes an additional branch
(thyroidea media, t. ima) from the arteria
innominata, or the arch of the aorta, which
ascends upon the front of the trachea. The
arteries are remarkable for their large size
and frequent anastomoses. The veins form
a plexus on the surface of the gland, and on
the front of the trachea, from which arise
the superior, middle, and inferior thyroid
veins; the two former terminating in the
internal jugular, the latter in the vena in-
nominata. The lymphatics are numerous,
of large size, and terminate in the thoracic
and right lymphatic ducts. They are thus described bv Frey: "The whole
envelope of the organ is covered by knotted trunks, which take their origin
from a network of very complicated canals, situated in a deeper layer of the
former. This latter network is formed around the secondary lobules of the
gland by the reticular intercommunications of these canals (Fig. 479,/). From
the peripheral network formed of canals burrowing through the connective
tissue of the capsule, lateral ramifications are given off which penetrate into the
interior, and gradually inclose the primary lobes in complete rings, or more or
less perfect arches (cZ, d). From these a few fine terminal passages with blind
ends (e) are seen sinking in between the different vesicles." The nerves are
M,
a. Small glandular vesicles with their cells ; h,
the same -with incipient colloid metamoi-pbosis,
more strongly marked &t c ; d, coarse lymph-ca-
nals ; e, fine radicles of the same ; /, au efferent
■vessel of considerahle size.
836 ORGANS OF VOICE AND RESPIRATION.
derived from tlie pneumogastric,^ and from the middle and inferior cervical
ganglia of tlie sjm pathetic.
Chemical Composition. The thyroid gland consists of albumen, traces of
gelatine, stearine, oleine, extractive matter, alkaline and earthy salts, and water.
The salts are chloride of sodium, alkaline sulphates, phosphate of potash, lime,
magnesia, and a trace of oxide of iron.
Thymus Gland.
The Thymus Gland presents much resemblance in structure to other glandular
organs, and is another of the organs denominated ductless glands.
The thymus gland is a temporary organ, attaining its full size at the end of
the second year, when it ceases to grow, and gradually dwindles, until, at
puberty, it has almost diapj)eared. If examined, when its growth is most active,
it will be found to consist of two lateral lobes, placed in close contact along the
middle line, situated partly in the anterior mediastinum, partly in the neck, and
extending from the fourth costal cartilage upwards, as high as the lower border
of the thj^roid gland. It is covered by the sternum, and by the origins of the
Sterno-hyoid and Sterno-thyroid muscles. In the mediastinum, it rests upon
the pericardium, being separated from the arch of the aorta and great vessels by
the thoracic fascia. In the neck, it lies on the front and sides of the trachea,
behind the Sterno-hyoid and Sterno-thyroid muscles. The two lobes generally
differ in size ; they are occasionally united, so as to form a single mass ; and
sometimes separated by an intermediate lobe. The thymus is of a pinkish-gray
color, soft and lobulated on its surfaces. It is about two inches in length, one
and a half in breadth, below, and about three or four lines in thickness. At
birth it weighs about half an ounce.
Structure. Each lateral lobe is composed of numerous lobules, held together-
by delicate areolar tissue; the entire gland being inclosed in an investing capsule
of a similar, but denser structure. The primary lobules vary in size from a
pin's head to a small pea. Each lobule contains, in its interior, a small cavity,
which is surrounded with smaller or secondary lobules also hollow. The
cavities of the secondary and primary lobules communi-cate ; those of the latter
opening into the great central cavity, or reservoir of the tliym.us^ which extends
through the entire length of each lateral half of the gland. The central cavity
is lined by a vascular membrane, which is prolonged into all the subordinate
cavities, and contains a milk-white fluid resembling chyle.
If the investing capsule and vessels, as well as the areolar tissue connecting
the lobules, are removed from the surface of either lateral lobe, it will be seen
that the central cavity is folded upon itself, and admits of being drawn out into
a lengthened tubular cord, around which the primary lobules are attached in a
spiral manner, like knots upon a rope. Such is the condition of the organ at an
early period of its development ; for Mr. Simon has shown, that the primitive
form of the thymus is a linear tube, from which as its development proceeds,
lateral diverticula lead outwards, the tube ultimately becoming obscure, from its
surface being covered Avith numerous lobules.
According to Oestcrlen and Mr. Simon, the cavities in the secondary lobules
are surrounded by rounded saccular dilatations or vesicles, which open into it.
These vesicles are formed by a homogeneous membrane, inclosed in a dense
capillary plexus.
The primary lobules are made \v^ of numerous small polyhedral granules, or
acini^ which bear a considerable resemblance to the lymphoid folHclcs of the
tonsils, intestine, and other parts, except that they are usually described as
containing a central cavity, which is, in fact, a diverticulum from the general
cavity of the gland. By many observers, however, both the cavity of the acini
and the general cavity are regarded as the effect of post-mortem changes. Ex-
' Frc'j' (Irnics tliat the vagus supplies auy of these nerves, deriving tlicm entirely from the
gynipathotic.
THYMUS GLAND.
837
ternal to tliis central cavity with its chylelike con-
tents lie the capillary vessels of the acinus, em-
bedded in a large quantity of lymphoid tissue.
The elements which are found in the acini are
chiefly granular free nuclei (a), lymphoid cells
(b), larger cells, some of them many-nucleated, and
often undergoing fatty degeneration (d, e, /), and
peculiar encapsulated bodies, some of them merely
the foregoing cells surrounded by concentric layers
(fj), others consisting of an assemblage of the for-
mer inclosed in a kind of nest, like the "bird-nest
cells" found in epithelioma.
Vessels and Nerves. The arteries supplying the
thymus are derived from the internal mammary,
and from the superior and inferior thyroid. The
veins terminate in the left vena innominata, and in
the thyroid veins. The hjmj^hatics are of large size,
arise in the substance of the gland, and are said to
terminate in the internal jugular vein. Sir A.
Cooper believed that these vessels carried into the
blood the secretion formed in the substance of the
thymus. The nerves are exceedingly minute ; they
are derived from the pneumogastric and sympa-
thetic. Branches from the descendens noni and
phrenic reach the investing capsule, but do not
penetrate into the substance of the gland.
Chemical Cotnposition. The solid animal consti-
tuents of the thymus are albumen and tibrine in
large quantites, gelatine and other animal matters.
The salts are alkaline and earthy phosphates, with
chloride of potassium. It contains about 80 per
ri«?. 480.
1. Upper portion of the tliymus of a
foetal pig of 2" in length, showing the
bud-like lobuli and glandular elements,
2. Cells of the thymus, mostly from
man ; a, free nuclei ; 6, small cells ; e,
larger ; d, larger with oil-globules,
from the ox ; e, f, cells completely
filled with fat, at / without a nucleus ;
gr, h, concentric bodies ; g, an encapsu-
lated nucleated cell ; h, a composite
structure of a similar nature.
cent, of water.
The Urinary Organs.
Fig. 481. — Vertical Section of Kidney.
The Kidneys.^
Defiottion" and General Description. The kidneys are the two largest
tubular glands of the body, and are intended for the secretion of urine. They
are found at the back part of the abdomen, behind the peritoneum, situated in
the lumbar regions : each kidney extending from the eleventh rib nearly to the
crCvSt of the ilium, but the right a little lower than the left, in consequence of
the large space occupied by the liver. They are usually embedded in a con-
siderable quantity of fat, which- principally holds them in position, though they
are also to some extent sustained by the large bloodvessels with which they are
connected.
Each kidney is about four inches in length, two in breadth, and one in thick-
ness, the left being somewhat larger, though thinner, than the right. The
weight of the kidney in the adult male varies from -ij oz. to 6 oz., in the adult
female from 4 oz. to 5| oz., the left being nearly always heavier than the right
by about two drachms. The combined weight of the two kidneys in proportion
to the body is about 1 to 240. The renal sub-
stance is of a dark red color, and dense in
texture ; but it is easily lacerable under
mechanical force.
Relations. Each kidney presents for exami-
nation two surfaces, two borders, an upper and
a lower extremity.
The anterior surface is convex and entirely
covered by peritoneum. It is in relation, on
the right side of the body, with the back part
of the right lobe of the liver, the descending
portion of the duodenum, and the ascending
colon ; and on the left, with the great end of
the stomach, the lower end of the spleen, the
tail of the pancreas, and the descending colon.
The posterior surface, flatter than the ante-
rior, rests upon the corresponding crus of the
diaphragm in front of the eleventh and twelfth
ribs, the anterior lamella of the aponeurosis of
the transversalis abdominis which separates it
from the quadratus lumborum, and on the
psoas magnus.
The external harder is convex, and directed
outwards and slightly fonvards, towards the
pnrictes of the abdomen.
The internal border, concave, is interrupted
at its central portion by a notch or fissure of
about an inch in length, cnlled the hiluw, of the kidney. This fissure opens
into a liollow cavity called the sinus, and through it ymss the vessels, duct
(ureter), nerves, and lymphatics of tlie kidney enveloped in fat and cellular
tissue. TiCt the vessels, nerves, duct, and f;it be removed so as to leave only the
' 'I'lir- (Ifscriptioii is fVdin iIk,; pen of my frifuil ]\Ir. 10. J. Spilta, laic Demonstrator of Anatomy
at St. Geopfjo's Hospilal.
838)
^Mta^ij^iiiJ^
THE KIDNEYS.
839
kidney proper ; tlie liilum will be seen opening into the sinus just as, in oste-
ology, a fissure opens into a fossa. The relation of the hilum to the sinus will
be understood by comparing Fig. 481, 482. In the former the hilum and sinus
are seen in section, the hilum occupied by the commencement of the ureter
proper, the sinus filled by the pelvis. In the latter figure, the pelvis has been
separated from the greater part of the sinus of the kidney, and partially lifted
out of it. The relative position of the vessels and ureter to each other is usually,
although not always, as follows : from above downwards ; artery, vein, ureter :
from before backwards ; vein, artery, ureter.
Fig. 482.— Diagram of the Hilum, Sinus, and Pelvis of the Kidney.
a. The liilum cut open, leading iuto (h) the sinus, c. The pelvis of the ureter partly separated from the walls of the
sinus, and lifted out: the ureter is seen continuous with it, and emerging from the hilum below, d, e. The renal artery
and vein passing through the sinus.
The siqierior extremity^ directed slightly inwards as well as upwards, is thick
and rounded, and embraced by the suprarenal capsule. It corresponds on the
left side with the upper, and on the right with the lower border of the eleventh
rib.
The inferior extrernity^ directed a little outwards as well as downwards, is
smaller than the superior and more flattened ; it extends nearly as low as the
crest of the ilium.
General structure of the Kidney. The structure of the kidney, as seen
by the naked eye on making a section from its convex to its concave border,
will be found to consist of two parts ; the glandular portion, or kidney 'proper^
and its excretory duct or tirete.r^ which latter will be described separately.
The kidney proper presents two distinct parts : tlie outer or cortical portion^
surrounded by the capsule^ and the inner or medullary^ which latter is arranged
in large conical masses called the pyramids of Malpighi.
' In this section the two first portions of the duct are alone seen. These are usually called the
calices and pelvis of the Tcidney ; but inasmuch as they are really part of the ureter, they will be
described under that head.
840
URINARY ORGANS.
The capsule is a fibrous coat formed of dense areolar tissue. It is thin and
smooth and easily removed from the cortical structure, to which it is connected
only by small bloodvessels and by numerous fine fibrous processes continuous
with the connective tissue of the kidney. At the hilum it is reflected inwards so
as to line the sides of the sinus; and at the floor of that cavity becomes continu-
ous with the fibrous sheaths of the vessels and nerves, and with the cup-like
commencements of the ureter above mentioned, called the calices.
The cortical structure is of a reddish-brown color, soft, granular, and easily
lacerable. It is found everywhere immediately beneath the capsule, and is seen
to extend itself in an arched form over each medullary pyramid. The part
se23arating the sides of any two pyramids, through which the arteries and nerves
enter and the veins and lymj)hatics emerge from the kidnej'', is called a cortical
Fig. 483. — Minute Structure of Kidney.
Fig. 484. — Diagrammatic Representation of the
Bloodvessels in the Substance of the Cortex of the
Kidney.
m. r^egion of the medullary ray. 5. Regionof the tortuous portion
of the tubules, ai. Arteria interlohularis. vi. Vena interlobularis.
va. Vas aflferens. gl. Glomerulus, ve. Vas efferens. vz. Venous
twig of the interlobularis. (From Ludwig, in Strieker's " Hand-
book.")
column, or column of Bertini (a, a'. Fig. 481); whilst that portion Avhich
stretches from one cortical column to the next, and intervenes between the
base of the pyramid and the capsule, which is marked by the dotted line, ex-
tending from A to a' (Fig. 481), is called a cortical arch, the depth of which
varies from a third to half an inch. The cortical structure is composed of con-
voluted and straight tubes called tubuli uriniferi ; of bloodvessels, nerves, and
lymphatics ; and also of numerous little red masses disseminated throughout its
substance known as the Malpi(jhian bodies. These bodies, with the interstitial
tissue connecting them, will be described under the head of the " Minute Struc-
ture of the Kidney."
Tlic m,edullary structure, as before said, is seen to consist of palish-red colored
striated conical masses, i\\G pyramids of Malpiglii; the number of which, vary-
ing from eight to eiglitccn, corresponds to the number of lohes of which the
organ in tlie foetal state is composed. Tlie hase of each pyramid is surrounded
by a cortical arch and directed towards the circumference of the kidney ; the
sides arc cf)ntigiK)us with tlic cortical columns ; whilst the apex, known as the
papilla or murnilla of the kidney, is covered by mucous mcml)rane and is seen
projecting into one of the calices of the ureter.
In addition to the arteries and veins and the "looped tubes of ITenlc," here-
after to be described, each pyramid is composed of a large number of straight
uriniferous tubes passing from base to apex, and which, by repeated inoscula-
THE KIDNEYS.
841
tions at very acute angles, are reduced to a comparatively small number, and
terminate in open mouths on the mucous surface of the mamilla.
Minute structure of the Kidney. Under this head the Malpighian bodies
will be first described ; then the course and structure of the tubuli uriniferi; and
lastly, the bloodvessels, nerves, lymphatics, and connective tissue or intertubular
stroma.
The Malpighian hodies are small rounded masses averaging Y^4th of an inch
in diameter, of a deep red color, found only in the cortical structure of the kid-
ney ; being scattered throughout the columns of Bertini, but regularly disposed
in double rows in the cortical arches. Each of these little bodies is composed
of two parts : a central glomerulus of vessels called a Malpighian tuft^ and a
membranous envelope, the Malpighian capsule^ which latter is a small pouch-
like commencement of a uriniferous tubule.^
The Malpighian tuft^ or vascular glomerulus, consists of the ramifications of
certain small vessels termed afferent and eft'erent renals, the latter being usually
smaller than the former. Each renal afferent in the cortical arches is derived
from an interlobular artery (Fig. 48-i), but in the cortical columns it springs
from one of the arteriae propriae renales (Fig. 491). Having pierced the capsule,
usually at a point opposite to the commencing tubule (Figs. 483, 484), it divides
in a radiating or tuft-like manner into several terminal branches, which ulti-
mately inosculate so as to form a network of capillaries, from which the efferent
arises [gl^ Fig. 484). This latter vessel makes its egress from the capsule near
to the point where the afferent enters ; and then, anastomosing with other effe-
rents from other tufts, contributes to form a dense venous p)lexus around the
urinary tubes adjacent (shown at m in Fig. 484).
The Malpighian capsule^ which surrounds the glomerulus, is formed of homo-
geneous membrane, thicker here than at any other part of the tube. It is
pierced at a point usually opposite the centre of the tubule, with which it is
continuous, by the afferent and efferent renals, and is lined upon its inner sur-
face by a delicate layer of either cubical or squamous epithelium ; but as regards
this layer, whether it is prolonged over the tuft either in whole or in part, there
is a diversity of opinion among many of the most eminent observers. Accord-
ing to Heme, Ecker, and Bowman, it is not reflected upon the tuft at all, so that
Fiff. 485.
the latter hangs free and uncovered in the interior of the capsule (Fig. 485 A) ;
on the other hand, Gerlach, Isaachs, Moleschott, and Chrzonszczewsky assert
that it can be traced upon the whole of the tuft, and that the cells are even
larger and better marked than those upon the internal surface of the capsule
' In former editions of this work, the Malpighian capsule was said to be found at the side as
well as the commencement of a tubule (Gerlach) ; only the latter position, however, is now recog-
nized in the human subject.
842
UEINARY ORGANS.
Fii?. 486.
A. Blalpighian tody. B. Convoluted uriniferous tube. B'
loop of Henle (intercalated convoluted tube of Schaltstiick).
Portion intervening between tlie straight tube and the
C C. Looped tube of Henle. D. Straight tube.
Fig. 487.
A A. DlaKrammaHcal nketch of a
pyramid 'if I'orroln. B li. Marginof
medullary alructure. (' (' C. l/ooiis
of Hcnlo. D D I). StralKbt tnboH
cut off. E. Commencing Btralglit
tnbex. F. Torminutiou of straight
tube.
(Fig. 485 b) ; whilst yet a third arrangement has been
described by Kolliker, who says that the tuft has no
epithehal hning on the greater part of its extent, but
upon that portion Avhich looks towards the commenc-
ing tubule a special layer of cubical cells can always
be seen (Fig. 485 c). In the frog, the cells lining the
interior of the capsule, near its junction witli the
tube, are provided with cilia; bnt in the human sub-
ject their presence has not been satisfactorily demon-
strated.
Course of the TuhuU TJriniferi. The tnbuli nriniferi
commence as Malpighian capsules, and soon after their
origin have an average diameter of ^g-g-th of an inch.
Thus arising, they pass in so convoluted a manner
throughout the cortical substance as to merit the
name of tuhuli contorti. Many of them, according
to Henle, soon after their commencement, suddenly
become smaller and straighter, and, dipping down to
a variable depth in the medullary structure, and
returning from thence somewhat larger, re-enter the
cortical. The portion of the tube between the loop
and the straight tube is sometimes called the inter-
calated convoluted tube (b'. Fig. 473). The tubes
taking the course above described form a kind of-
loop, and are known as the looped or rec^irrcnt tubes
of Henle, the descending and ascending limbs of which
have the diameter of aA^^h and yo'snth of an inch
respectively. The ascending limbs, having arrived
at the cortical struct^^re, become again convoluted,
and, together with those of the tubnli contorti which
have not entered into the loops, end in the straight
tubes, or liibiili recti, next to be described.
Each si rail/Ill, otherwise called a collecttwj or re-
ceivifKj tuhe^ commences at about one line from the
THE KIDNEYS.
843
surface of the kidney by the coalescence of two or more of the convoluted tubes
above mentioned. Passing towards the medullary substance, it continues to
receive on either side more convoluted tubes, until at length it enters a pyramid
of Malpighi, where it joins at very acute angles with receiving tubes similarly
formed, and finally terminates by an opening at the mamillary apex, emptying
its contents into the calyx adjacent. According to Huschke there are about
a thousand straight tubes opening upon the apex of each pyramid, but their
number is estimated by Kcilliker at about five hundred.
It will be seen from the above description, that each of the straight tubes
whilst in the cortical structure is surrounded by numerous tubuli contorti ; and
hence, that a kind of ]3yramid is formed ; the apex of which consists of the
tubulus rectus as it enters the Malpighian pyramid, whilst the hase^ composed
of the commencing straight tube with the tubuli contorti from which it origi-
nates, looks towards the circumference of the kidney. Pyramids so formed are
called the pyramids of Ferrein. They have also been named " lobules of the
kidney," and the vessels which run between them " interlobular." The student
must not confound these with the lobes mentioned on jd. 840, of which the foetal
kidney is composed. The pyramids of Ferrein are found in the cortical arches
only, and were considered by Ferrein as quite distinct; but although they are
for the most part separated by interlobular vessels and two rows of Malpighian
bodies, yet it is noAV generally admitted that certain tubes of adjacent lobules
intercommunicate. In the columns of Bertini no definite lobular arrangement
is said to exist, on account of the absence of straight tubes; the tubuli contorti
of those parts meeting the tubuli recti at the hase of the Malpighian p3^ramids,
and not at the sides adjacent.
Fij?. 488.
-Transverse Section of Pyramidal Substance of Kidney of Pig, the bloodvessels
of which are injected.
a. Large collecting tube, cut across, lined with cylindrical epitlielium. J. Branch of collecting tube, cut across,
lined -with epithelium with shorter cylinders, e and d. Henle's loops cut across, e. Bloodvessels cut across. 1).
Connective tissue ground-suhstance.
Structure of the Tuhuli Uriniferi. The tubuli uriniferi consist of basement
membrane lined with epithelium. In the tubuli contorti it is more or less
spheroidal ; in the straight tubes and the ascending or larger limb of Henle's
loop large and cloudy, being of the cubical variety ; whilst in the descending
limb it is smaller and transparent, closely resembling the endothelium of blood-
vessels. Hence, although the two hmbs of Henle's loops difier much in size,
their hore is almost similar, owing to the difierent thickness of their epithelial
. lining.
The Renal Bloodvessels ; their origin, course, and distribution. The kidney is
plentifully supplied with blood by the renal artery, a large offset of the abdomi-
' From the " Handbook for the Physiological Laboratory."
844
URINARY ORGANS..
nal aorta, wliicli enters the sinus tlirougli tlie Hlum, dividing in its passage
through the latter into four or five branches. These, whilst in the sinus, give
Fig. 489.' — Longitudinal Section of Straight Fig. 490.' — Longituclinal Section of Heule's
Tube. Descending Limb.
a. Cyliudrical or cvibical epithelium.
6. Membrana propria.
a. Jlembrana propria.
b. Epithelium.
off a few twigs for the nutrition of the surrounding tissues, and terminate in the
arterise "pTO'iirise renales^ which enter the kidney proper in the columns of Bertini.
Two of these pass to each pyramid of Malpighi and run along its sides for its
entire length, giving off as they advance the afferent vessels of the Malpighian
Fig. 491.— Diagrammatical Sketcli of
Kidney.
Fig. 492.— A portion of Fig. 491 enlarged
(The references are the same).
A ri. Proper ronnl uricry dnrl vein, tho former fjlviiif? off the renal afforonts, the latter roceivinir the renal efTerents.
V, Ij. Irjtorlobularnrtery and vein, the latter commencing from the stellate veins, and receiving brandies from the
pl"-.\ns aronnd the tiibull contorll, tlio former giving off renal afforonts. 0. fftralght tube, Hurroundod by tiibnli
contortl, witli wliich it coininunlcates, forming a jiyramid of I'orrein, as more fnlly sliown in Fig. 487. D. Margin of
medullary subHiancn. E E E. Koceiving tnbos, cut oU'. F/. Artoriolaj ot vena3 roctw, tlie latter arising from (G) the
plexuK at the medullary apex.
bodies in llic rolunnis. lliiving jirrivcil ;it the bases of the pyramids, they make
a bend ill tiioir course, so as to lie between tlie bases of the pyramids and the
From llic " Iliuidhook for tlie Fliysiological Laboratory."
THE KIDNEYS. 845
cortical arclies, where tliej break up into two distinct sets of brandies devoted
to tbe supply of the remaining portions of the kidney.
The first set, the interlobular arteries (Figs. 491, 492, b), are given off at
right angles from the side of the arterise proprise renales looking towards the
cortical substance, and passing directly outwards between the pyramids of
Ferrein, supply the capsule, terminating in the stellate plexus of veins beneath
that structure. In their outward course they support the Malpighian bodies by
supplying them with afferent vessels, which, having pierced the capsule, end in
the Malpighian tufts. From each tuft the corresponding renal efferent arises,
which, having made its egress from the capsule near to the point where the
afferent entered, anastomoses with other efferents from other tufts, and contri-
butes to form a dense venous plexus around the urinary tubes adjacent.
The second set from the arterise proprise renales are for the supply of the
medullary pyramids, which they enter at their bases; and passing through their
substance straight to their apices, terminate in the venous plexuses found in that
situation. They are called the arteriolse rectse (Figs. 491, 492, f).
The Renal Veins arise from three sources : the veins beneath the capsule, the
plexuses around the tubuli contorti in the cortical arches, and the plexus situ-
ated at the apices of the pyramids of Malpighi. The veins beneath the capsule
are stellate in arrangement, being found around the bases of the pyramids of
Ferrein, and are derived from the terminations of the interlobular arteries.
These join to form the venee interlohulares^ which pass inwards between the pyra-
mids of Ferrein, receive branches from the plexuses around the tubuli contorti,
and, having arrived at the bases of the Malpighian pyramids, join with the
vense rectse, next to be described (Figs. 491, 492, b).
The Vense rectse are branches from the plexuses at the apices of the medullary
pyramids, formed by the terminations of the arteriole rectas. They pass out-
wards in a straight course between the tubes of the medullary structure, and
joining, as above stated, the vense interlobulares, form the proper renal veins
(Figs. 490, 491,/).
These vessels, vense proprise renales^ accompany the arteries of the same
name, running along the entire length of the sides of the pjn-amids; and, having
received in their course the efferents from the Malpighian bodies in the cortical
structure adjacent, quit the kidney proper to enter the sinus. In this cavity
they inosculate with the corresponding veins from the other pyramids to form
The Renal Vein, which, passing through the hilum, opens into the vena cava
inferior; the left being longer than the right, from having to cross in front of
the abdominal aorta.
Nerves of the Kidney. The nerves of the kidney, although small, are about
fifteen in number. They have small ganglia developed upon them, and are
derived from the solar plexus, the lower and outer part of the semilunar gan-
glion, and from the lesser and smallest splanchnic nerves. They communicate
with the spermatic plexus, a circumstance which may explain the sympathy
that exists between the kidney and testicle. So far as they have been traced,
they seem to accompany the renal artery and its branches, but their exact mode
of termination is not known.
The lymphatics consist of a superficial and deep set which terminate in the
lumbar glands.
Connective tissue, or intertubular stroma. Although the tubules and vessels
are closely packed, a certain small amount of connective tissue, continuous with
the capsule, binds them firmly together. This tissue was first described b}^
Goodsir and subsequently by Bowman. Ludwig and Zawarykin have observed
distinct fibres passing around the Malpighian bodies ; and Henle has seen them
between the straight tubes composing the medullary structure.
84G URINARY ORGANS.
The Uretees.
The terra Ureter is generally restricted to that portion of the renal duct which
is between the pelvis of the kidney and the bladder, but in this description the
calices and pelvis of the kidney will be included in its composition. So that the
ureter, or excretory duct, of the kidney will be said- to consist of three portions;
its cuplike commencements, the calices^ including the infundibula; its dilated
portion, the pelvis ; and its tubular portion, the ureter projjer.
The calices are cup-like tubes encircling the apices of the Malpighian pyra-
mids; but inasmuch as one calyx may include two or even more papillae, their
number is generally less than the pyramids themselves, the former being from
seven to thirteen, whilst the latter vary from eight to eighteen. These calices
converge into the three infundibula^ an upper, middle, and lower, which by
their junction form the pelvis^ or dilated portion of the ureter; which latter,
gradually narrowing, becomes continuous with the ureter proper. The portion
last mentioned, where the pelvis merges into the ureter proper, is found opposite
the transverse process of the third lumbar vertebra on the left, and the fourth
on the right side; at either of which situations it is accessible behind the perito-
neum.
The ureter proper is a cylindrical membranous tube, from sixteen to eighteen
inches in length, and of the diameter of a goose-quill, extending from the pelvis
of the kidney to the bladder. Its course is obliquely downwards and inwards
through the lumbar region into the cavity of the pelvis, where it passes down-
wards, forwards, and inwards across that cavity to the base of the bladder, into
which it then opens by a constricted orifice, after having passed obliquely for
nearly an inch between its muscular and mucous coats.
Relations of the ureter proper. In its course it rests upon the psoas muscle,,
being covered by the peritoneum, and crossed obliquel}^, from within outwards,
by the spermatic vessels; the right ureter lying close to the outer side of the
inferior vena cava. Opposite the first piece of the sacrum it crosses the common
iliac artery, lying behind the ileum on the right side and the sigmoid flexure of
the colon on the left. In the pelvis it enters the posterior false ligament of the
bladder, below the obliterated hypogastric artery, the vas deferens in the male
passing between it and the bladder. In the female the ureter passes along the
sides and cervix uteri and upper part of the vagina. At the base of the bladder,
it is situated about two inches from its fellow ; lying, in the male, about an inch
and a half behind the base of the prostate, at the posterior angle of the trigone.
Structure. The ureter is composed of three coats, a fibrous, muscular, and
mucous.
^\\Q fihrous coat is the same throughout the entire length of the duct, being
continuous at one end with the capsule of the kidney at the floor of the sinus;
whilst at the other it is lost in the fibrous structure of the bladder.
The muscular coat consists of turn layers in the calices and pelvis, but of three
in the ureter proper.
Tlic external or longitudinal fibres of the calices are lost upon the sides of
the mamilloe, whilst the internal or circular serve to grasp the medullary struc-
ture in the same situation.
The three layers found in the ureter proper (two longitudinal with an inter-
vening circular layer) arc all continuous witli the muscuhar fibres of the bladder.
The mucous coat is smooth and presents a few longitudinal folds which become
effaced by distension. It is continuous with the mucous membrane of the
bladder below, whilst it is prolonged over the mamilla? of the kidney above.
Its epithelium consists principally of the spheroidal variety, but at that portion
of the ureter near the bladder it is said to be divided into three layers. The
inner layer, that in contact with the urine, is irregular or quadrilateral in shape ;
the second or intermediate la)'cr more or less resembles columnar epithelium
SUPRARENAL CAPSULES. 847
■with irreg-ular extremities; whilst the external or third layer is more or less
spheroidal.
The arteries supplying the nreter are branches from the renal, spermatic,
internal iliac, and inferior vesical.
The nerves are derived from the inferior mesenteric, spermatic, and hypo-
gastric plexuses.
Suprarenal Capsules.
The Suprarenal Capsules are usually classified together with the spleen,
thymus and thyroid, under the head of "ductless glands,'" as they have no
excretory duct. They are two small flattened glandular bodies, of a yellowish
color, situated at the back part of the abdomen, behind the peritoneum, and
immediately in front of the upper part of either kidney; hence their name.
The right one is somewhat triangular in shape, bearing a resemblance to a
cocked hat ; the left is more semilunar, and usually larger and higher than the
right. They vary in size in different individuals, being sometimes so small as
to be scarcely detected ; their usual size is from an inch and a quarter to nearly
two inches in length, rather less in width, and from two to three lines in thick-
ness. In weight, they vary from one to two drachms.
Relations. The anterior surface is in relation, on the right side, with the under
surface of the liver ; and on the left with the pancreas and spleen. The ■posterior
surface rests upon the crus of the Diaphragm, opposite the tenth dorsal vertebra.
The upper thin convex border is directed upwards and inwards. The lower thick
concave border rests upon the upper end of the kidney, to which it is connected
by areolar tissue. The inner border is in relation with the great splanchnic
nerves and semilunar ganglion, and lies in contact on the right side with the
inferior vena cava, and on the left side with the aorta. The surface of the supra-
renal gfend is surrounded by areolar tissue containing much fat, and closely
invested by a thin fibrous coat, which is difficult to remove, on account of the
numerous fibrous processes and vessels which enter the organ through the furrows
on its anterior surface and base.
Structure. On making a perpendicular section, the gland is seen to consist of
two substances : external or cortical, and internal or medullary.
The intimate structure of the suprarenal gland may be described as consisting
of three elements : the capsule and its processes, the cells, and the bloodvessels.
On section the gland is seen to consist of two parts, a cortical external, and a
medullary internal. The former, which constitutes the chief part of the organ, is
of a deep yellow color, and consists chiefly of narrow columnar masses placed per-
pendicularly to the surface. The medullary substance is soft, pulpy, and of a
dark brown or black color, whence the name atrahiliary capsules., formerly given
to these organs. In the centre is often seen a space, not natural, but formed by
the breaking-down after death of the medullary substance.
The cortical portion owes its arrangement to the disposition of the capsule,
which sends into the interior of the gland processes passing in vertically and
communicating with each other by transverse bands, so as to form cells Avhich
open into each other. These cells are of slight depth near the surface of the
organ, so that there the section somewhat resembles a net, but they become
much deeper or longer further in, so as to resemble pipes or tubes place endwise.
Still deeper down, near the medullary part, the cells become again of small
extent. The interior of these cells contains the ramifications of the capillaries,
but the greater part of them is filled with a mass of nucleated cells containing
large nuclei and many fat granules, with numerous pigment granules in the parts
where color is most conspicuous.
In the medullary portion, the fibrous stroma seems to be collected together
into a much closer arrangement, and forms bundles of stout connective tissue
which are loosely applied to the large plexus of veins of which this part of the
848
UEINARY ORGANS.
organ mainly consists. In the interstices lie a number of cells compared by
Frey to those of columnar epithelium. But the tissue of the medullary sub-
stance is less easy to make out than that of the cortical, owing to its rapid de-
composition.
Fio-. 493.
Fi<?. 494
Cortical portion of human suprarenal body under
a high magnifying power, a, Gland cylinders ;
6, interstitial connective tissue.
Transverse section through the cortical substance of the
human suprarenal budy. a, Frameworli of connective tissue';
b, capillaries ; c, nuclei ; d, gland-cells.
Thus we see that the numerous arteries which enter the suprarenal bodies
from the sources mentioned below penetrate the cortical part of the gland, where
they break up into capillaries in the fibrous septa, and these converge to the
very numerous veins of the medullary portion, which are collected together into
the suprarenal vein, which usually emerges as a single vessel from the centre
of the gland.
The medulla also contains a very large quantity of nerve-fibres.
The arteries supplying the suprarenal capsules are numerous and of large size ;
they are derived from the aorta, the phrenic, and the renal ; they subdivide into
numerous minute branches previous to entering the substance of the gland.
The suprarenal vein returns the blood from the medullary venous plexus, and
receives several branches from the cortical substance ; it opens on the right side
into the inferior vena cava, on the left side into the renal vein.
The lymphatics terminate in the lumbar glands.
The nerves arc exceedingly numerous ; they are found chiefly if not entirely
in the medulla, and are derived from the solar and renal plexuses, and, according
to Bergmann, from the phrenic and pneumogastric nerves. They have numerous
small ganglia developed upon them, from which circumstance the organ has been
conjectured to have some function in connection with the sympathetic nervous
system.
THE PELVIS.
The cavity of the Pelvis is that ])art of the general abdominal cavity Avhich
is below the level of the linca ilio-pcctinea and the promontory of the sacrum.
Boundaries. It is bounded, behind, by the sacrum, the coccyx, and the great
sacro-sciatic ligaments ; in front and at the sides by the pubcs and ischia, covered
BLADDER.
849
"by the Obturator muscles ; above, it communicates with the cavity of the abdo-
men ; and below, it is limited by the Levatores ani and Coccygei muscles ; and
the visceral layer of the pelvic fascia, which is reflected from the wall of the
pelvis on to the viscera.
Contents. The viscera contained in this cavity are the urinary bladder, the
rectum, and some of the generative organs peculiar to each sex ; they are
partially covered by the peritoneum, and supplied with blood and lymphatic
vessels and nerves.
The Bladder.
The Bladder is the reservoir for the urine. It is a musculo-membranous sac,
situated in the pelvis, behind the pubes, and in front of the rectum in the male,
the uterus and vagina intervening between it and that intestine in the female.
The shape, position, and relations of the bladder are greatly influenced by age,
sex, and the degree of distension of the organ. During infancy^ it is conical in
shape, and projects above the upper border of the pubes into the hypogastric
region. In the adult, when quite empty and contracted, it is a small triangular
sac, placed deeply in the pelvis, flattened from before backwards, its apex reach-
ing as high as the upper border of the symphysis pubis. When slightly dis-
tended, it has a rounded form, and partiall)^ fills the pelvic artery ; and when
greatly distended, it is ovoid in shape, rising into the abdominal cavity, and
often extending nearly as high as the umbilicus. It is larger in its vertical
Fig. 495. — Vertical Section of Bladder, Penis, and Urelhra.
Prep uce
diameter than from side to side, and its long axis is directed from above obliquely
downwards and backwards, in a line directed from some point between the pubes
and umbilicus (according to its distension) to the end of the coccyx. The bladder,
when distended, is shghtly curved forwards towards the anterior wall of the
abdomen, so as to be more convex' behind than in front. In the female, it is
54
850 URINARY ORGANS.
larger in tlie transverse than in tlie vertical diameter, and its capacity is said to
be greater than in the male. When moderately distended, it measures about
five inches in length, and three inches across, and the ordinary amount which
it contains is about a pint.
The bladder is divided into a summit, body, base, and neck.
The summit^ or apex, of the bladder is rounded and directed forwards and
upwards ; it is connected to the umbilicus by a fibro-muscular cord, the urachus,
and also by means of two rounded fibrous cord, the obliterated portions of the
hypogastric arteries, which are placed one on each side of the urachus. The
summit of the bladder behind the urachus is covered by peritoneum, whilst the
portion in front of the urachus has no peritoneal covering, but rests upon the
abdominal wall.
The urachus is the obliterated remains of a tubular canal which exists in the
embryo, and connects the cavity of the bladder with a membranous sac placed
external to the abdomen, opposite the umbilicus, called the allantois. In the
infant, at birth, it is occasionally found pervious, so that the urine escapes at the
umbilicus, and calculi have been found in its canal.
The hody of the bladder in front is not covered by peritoneum, and is in
relation with the triangular ligament of the urethra, the posterior surface of the
symphysis pubis, the Internal obturator muscles, and, when distended, with the
abdominal parietes.
The posterior surface is covered by peritoneum throughout. It corresponds,
in the male, with the rectum ; in the female, with the uterus, some convolutions
of the small intestine being interposed.
The side of the bladder is crossed obliquely from below, upwards and for-
wards, by the obliterated hypogastric artery ; above and behind this cord, the
bladder is covered by peritoneum ; but below and in front of it the serous cover-
ing is wanting, and it is connected to the pelvic fascia. The vas deferens passes,
in an arched direction, from before backwards, along the side of the bladder,
towards its base, crossing in its course the obliterated hypogastric artery, and
passing along the inner side of the ureter.
The hase {fundus) of the bladder is directed downwards and backwards. It
varies in extent according to the state of distension of the organ, being very
broad when full, but much narrower when empty. Li the mcde, it rests upon
the second portion of the rectum, from which it is separated by a reflection of
the recto-vesical fascia. It is covered posteriorly, for a slight extent, by the
peritoneum, which is reflected from it upon the rectum, forming the recto-vesical
fold. The portion of the bladder in relation with the rectum corresponds to a
triangular space, bounded behind by the recto-vesical fold; on either side, by
the vesicula seminalis and vas deferens; and touching the prostate gland in front.
When the bladder is very full, the peritoneal fold is raised with it, and the
distance between its reflection and the anus is about four inches ; but this dis-
tance is much diminished when the bladder is empty and contracted. In the
female, the base of the bladder lies in contact with the lower part of the cervix
uteri, is adherent to the anterior wall of the vagina, and separated from the
upper part of the anterior surface of the cervix uteri by a fold of the peritoneum.
The neck {cervix) of the bladder is the constricted portion continuous with the
urethra. In the male, its direction is oblique in the erect posture, and it is sur-
rounded by the prostate gland. In the female its direction is obliquely down-
wards and forwards.
Li;/aments. The bladder is retained in its place by ligaments which are
divided info true and false. The true ligaments are five in number, two anterior,
and tAVo lateral, formed by the recto-vesical fascia, and the urachus. ^I'hc false
ligaments, also five in number, are formed by folds of the peritoneum.
The anterior lif/arn,ents ( puho-prostatic) extend from the back of the pubes, one
on each side of the symphysis, to the front of the neck of the bladder, and upper
BLADDER. 851
surface of the prostate gland. These ligaments contain a few muscular fibres
prolonged from the bladder.
The lateral ligaments^ broader and thinner than the preceding, are attached to
the lateral parts of the prostate, and to the sides of the base of the bladder.
The urachus is the fibro-muscular cord already mentioned, extending between
the summit of the bladder and the umbilicus. It is broad below, at its attach-
ment to the bladder, and becomes narrower as its ascends.
The false ligaments of the bladder are, two posterior, two lateral, and one
superior.
The two posterior pass forwards, in the male, from the sides of the rectum ; in
the female, from the sides of the uterus, to the posterior and lateral aspect of the
bladder : they form the lateral boundaries of the recto-vesical fold of the peri-
toneum, and contain the obliterated hypogastric arteries, and the ureters, together
with vessels and nerves.
The two lateral ligaments are reflections of the peritoneum, from the iliac fossse
to the sides of the bladder.
The superior ligament is the prominent fold of peritoneum extending from the
summit of the bladder to the umbilicus. It covers the urachus, and the oblite-
rated hypogastric arteries.
Structure. The bladder is composed of four coats : a serous, a muscular, a
cellular, and a mucous coat.
The serous coat is partial, and derived from the peritoneum. It invests the
posterior surface, from opposite the termination of the two ureters, to its
summit, and is reflected from this point and from the sides, on to the abdominal
and pelvic walls.
The muscular coat consists of two layers of unstriped muscular fibre, an
external layer, composed of longitudinal fibres, and an internal layer of circular
fibres.
The longitudinal fibres are most distinct on the anterior and posterior surfaces
of the organ. They arise in front, from the anterior ligaments of the bladder,
from the neck of the bladder, and, in the male, from the adjacent portion of the
prostate gland. They spread out, and form a plexiform mesh, on the anterior
surface of the bladder, being continued over the posterior surface, and base of
the organ of the neck, where they are inserted into the prostate in the male, and
into the vagina in the female.
Other longitudinal fibres arise in the male from the sides of the prostate, and
spread out upon the sides of the bladder, intersecting with one another.
The circular fibres are very thinly and irregularly scattered on the body of
the organ ; but, towards its lower part, round the cervix and commencement of
the urethra, they are disposed as a thick circular layer, forming the sphincter
vesicEe, which is continuous with the muscular fibres of the prostate gland.
Two bands of oblique fibres, originating behind the orifices of the ureters,
converge to the back part of the prostate gland, and are inserted, by means of
a fibrous process, into the middle lobe of that organ. They are the muscles of
the ureters^ described by Sir C. Bell, who supposed that, during the contraction
of the bladder, they served to retain the oblique direction of the ureters, and so
prevent the reflux of the urine into them.
J. B. Pettigrew gives the following results at which he has arrived by his exquisite dissections
of the muscular fibres of the bladder and prostate [PMla. Trans. 1867). The muscular fibres of
the bladder are arranged spirally, forming figure-of-8 loops, the superficial more longitudinal or
drawn out, the deeper more circular or flattened. This arrangement has been aptly compared
to that of india-rubber rings through which a stick has been passed and which are then wound
twice round the stick and drawn out into figures-of-8, some (the exterior) in very elongated loops,
so as to approach the longitudinal direction, others (the central) in very flattened loops, so as to
be nearly circular. The external fibres, which are nearly longitudinal, are in four sets— an ante-
rior and posterior, and a right and left lateral ; the latter accessory and less fully developed.
The fibres are arranged in seven strata, three external, three internal, and a middle, pursuing
well-marked directions in each. These layers, however, are very imperfect, " the fibres rarely, if
ever, occupying precisely the same plane and running exactly parallel. They, moreover, split up,
852
URINARY ORGANS.
Fig. 496.— The Bladder and Urethra
laid open. Seen from above.
and become fused with each other, with corresponding" or homologous fibres, and with fibres
which are either superimposed or underlie them." Tlie fibres of the first and seventh layers are
the most feebly developed. The crossings or decussations of the loops occur at different distances
in proceeding from before backwards, this crossing forming a kind of spiral line. 'J'he loops are
directed towards and embrace the urachus and urethra respectively. The terminal expansions
of the loops in the other layers contribute to the formation of the fourth layer, particularly
towards the base and apex, which are, therefore, thicker than the other parts. The agcrega-
tion of the loops towards the apex forms the sphincter. The longitudinal, slightly oblique, truly
oblique, and nearly circular fibres of the successive layers are all continued into the prostatic
urethra, which therefore may be regarded as a continuation of the bladder anteriorly. '1 he fibres
of the cervix are traceable into the verumontanum, which Pettigrew believes to act as a valve
to the urethra, falling down into the tube and obstructing it when the muscle of the bladder
is not acting, and raised up, so as to stand erect in the middle line, and thus to allow the flow of
urine, when the fibres contract. The varying obliquity and spiral arrangement of the seven
layers establishes a close analogy between the disposition of the muscular fibres of the bladder
and those of the heart, as described by Pettigrew, in Phil. Trans. 1864 ; and he hints at similar
structure in the stomach and uterus.
The cellular coat consists of a layer of areolar tissue, connecting togetlier tlie
muscular and mucous coats, and intimately united to the latter.
The mucous coat is thin, smooth, and of a pale rose color. It is continuous
through the ureters with the lining membrane
of the uriniferous tubes, and below with that
of the urethra. It is connected loosely to the
muscular coat, by a layer of areolar tissue,
excepting at the trigone, where its adhesion is
more close. It is provided with a few mucous
follicles; and numerous small racemose glands,
lined with columnar epithelium, exist near the
neck of the organ. The epithelium covering
it is intermediate in form between the columnar
and squamous varieties.
Interior of the bladder.. Upon the inner sur-
face of the base of the bladder, immediately
behind the urethral orifice, is a triangular,
smooth surface, the apex of which is directed
forwards ; this is the trigonum vesicee or trigone
vesical. It is paler in color than the rest of the
mucous membrane, and never presents any
rugae, even in the collapsed condition of the
organ, owing to its intimate adhesion to the
subjacent tissues. It is bounded on each side
by two slight ridges, which pass backwards
and outwards to the orifices of the ureters,
and correspond with the muscles of these tubes ;
and at each posterior angle, by the orifices of
the ureters, which are placed nearly two inches
from each other, and about an inch nnd a half
behind the orifice of the urethra. The trigone
corresponds with the interval at the base of
the bladder, bounded by the prostate in front,
and the vesiculae and vasa defcrentia on the
sides. Projecting from the lower and anterior
])art of the bladder, into the orifice of the
urethra, is a slight elevation of mucous mem-
brane, called the uvula, vcsicse. It is foi'mcd by
a tliickening of the prostate.
The arteries su])])lying the bladder are the
superior, middle, and inferior vesical, in the
male, with additional bi'anclies from the uterine,
in tlic female. They are all derived from the anterior trunk of the internal
iliac.
Coii-fjet'tf C!a.
iij Courier's C.Uintlt
MALE URETHRA. 853
The veins form a complicated plexus round the neck, sides, and base of the
bladder, and terminate in the internal iliac vein.
The lymphatics accompany the bloodvessels, passing through the glands
surrounding them.
The nerves are derived from the hypogastric and sacral plexuses ; the former
supplying the upper part of the organ, the latter its base and neck.
Male Ueethea.
The Urethra extends from the neck of the bladder to the meatus nrinarius.
It presents a double curve in the flaccid state of the penis, but in the erect state
it forms only a single curve, the concavity of which is directed upwards (Fig.
495), Its length varies from eight to nine inches ; and it is divided into three
portions, the prostatic, membranous, and spongy, the structure and relations of
which are essentially different.
The Prostatic portion is the widest and most dilatable part of the canal. It
passes through the prostate gland, from its base to the apex, lying nearer its
upper than its lower surface. It is about an inch and a quarter in length ; the
form of the canal is spindle-shaped, being wider in the middle than at either
extremity and narrowest in front, where it joins the membranous portion, A
transverse section of the canal in this situation is triangular, the apex directed
downwards.
Upon the floor of the canal is a narrow longitudinal ridge, the verumontaniim,
or caput gallinaginis^ formed by an elevation of the mucous membrane and its
subjacent tissue. It is eight or nine lines in length, and a line and a half in
height; and contains, according to Kobelt, muscular and erectile tissues. When
distended, it may serve to prevent the passage of the semen backwards into the
bladder. On each side of the verumontanum is a slightly depressed fossa,
the prostatic sinus, the floor of which is perforated by numerous apertures, the
orifices of the prostatic ducts, the ducts of the middle lobe opening behind the
crest. At the fore part of the verumontanum, in the middle line, is a depression,
the sinus pocularis {vesicula prostatica) ; and upon or within its margins are the
slit-like openings of the ejaculatory ducts. The sinus pocularis forms a cul-de-sac
about a quarter of an inch in length, which runs upwards and backwards in the
substance of the prostate beneath the middle lobe ; its prominent upper wall
partly forms the verumontanum. Its walls are composed of fibrous tissue,
muscular fibres, and mucous membrane; and numerous small glands open on
its inner surface. It has been called by Weber, who discovered it, the uterus
masculinus, from its supposed homology with the female organ.
The Membranous portion of the urethra extends between the apex of the
prostate and the bulb of the corpus spongiosum. It is the narrowest part of the
canal (excepting the orifice), and measures three-quarters of an inch along its
upper and half an inch along its lower surface, in consequence of the bulb pro-
jecting backwards beneath it below. Its upper concave surface is placed about
an inch beneath the pubic arch, from which it is separated by the dorsal vessels
and nerves of the penis, and some muscular fibres. Its lower convex surface is
separated from the rectum by a triangular space, which constitutes the peri-
nasum. The membranous portion of the urethra perforates the deep perineal
fascia; and two layers from this membrane are prolonged round it, the one
forwards, the other backwards ; it is also surrounded by the Compressor urethraa
muscle. Its coverings are mucous membrane, elastic fibrous tissue, a thin
layer of erectile tissue, muscular fibres, and a prolongation from the deep
perineal fascia.
The Spongy portion is the longest part of the urethra, and is contained in the
corpus spongiosum. It is about six inches in length, and extends from the ter-
mination of the membranous portion to the meatus urinarius. Commencing
below the symphysis pubis, it ascends for a short distance, and then curves
854 URINARY ORGANS.
downwards. It is narrow, and of uniform size in the body of tlie penis,
measuring about a quarter of an inch in diameter; being dilated behind, within
the bulb: and again anteriorly within the glans penis, forming the fossa navicu-
laris. A cross section of this canal in the body of the penis has its long dia-
meter transverse ; but in the glans, that diameter is directed vertically.
The Bulbous 'portion is a name given, in some descriptions of the urethra, to
the posterior dilated part of the spongy portion contained within the bulb.
The meatus urinarius is the most contracted part of the urethra; it is a verti-
cal slit, about three lines in length, bounded on each side by two small labia.
The inner surface of the lining membrane of the urethra, esjDecially on the floor
of the s|)ongy portion, presents the orifices of numerous mucous glands and
follicles, situated in the submucous tissue, and named the glands of Littre.
They vary in size, and their orifices are directed forwards, so that they may
easily intercept the point of a catheter in its passage along the canal. One of
these lacunee, larger than the rest, is situated on the upper surface of the fossa
navicularis, about an inch and a half from the orifice; it is called the lacuna
•magna. Into the bulbous portion are found opening the ducts of Cowper's
glands.
Structure. The urethra is composed of three coats: a mucous, muscular, and
erectile.
The mucous coat forms part of the genito-urinary mucous membrane. It is
continuous with the mucous membrane of the bladder, ureters, and kidneys;
externally, with the integument covering the glans penis; and is prolonged into
the ducts of the glands which open into the urethra, viz., Cowper's glands, the
prostate gland, and the vasa deferentia and vesiculge seminales, through the
ejaculatory ducts. In the spongy and membranous portions the mucous mem-
brane is arranged in longitudinal folds when the organ is contracted. Small
papillae are found upon it, near the orifice; and its epithelial lining is of the
columnar variety, excepting near the meatus, where it is laminated.
The muscular coat consists of two layers of plain muscular fibres, an external
longitudinal layer, and an internal circular. The muscular tissue is most
abundant in the prostatic portion of the canal.
A thin layer of erectile tissue is continued from the corpus spongiosum
round the membranous and prostatic portion of the urethra to the neck of the
bladder.
Male Generative Organs.
Prostate Gland.
The Prostate Gland (npotanjAn, to stand before) is a pale, firm, glandular body,
which surrounds the neck of the bladder and commencement of the urethra.
It is placed in the pelvic cavity, behind and below the symphysis pubis, poste-
rior to the deep perineal fascia, and upon the rectum, through which it may be
distinctly felt, especially when enlarged. In shape and size it resembles a horse-
chestnut.
Its base is directed backwards towards the neck of the bladder.
The apex is directed forwards to the deep perineal fascia, which it touches.
Its under surface is smooth, and rests on the rectum, to which it is connected
by dense areolar fibrous tissue.
Its upper surface is flattened, marked by a slight longitudinal furrow, and
placed about three-quarters of an inch below the pubic symphysis.
It measures about an inch and a half in its transverse diameter at the base,
an inch in its antero-posterior diameter, and three-quarters of an inch in depth.
Its weight is about six drachms. It is held in its position by the anterior liga-
ments of the bladder [puho-prostatic) ; by the posterior layer of the deep perineal
fascia, which invests the commencement of the membranous portion of the
urethra and prostate gland ; and by the anterior portion of the Levator ani
muscle (levator prostates), which passes down on each side from the symphysis
pubis and anterior ligament of the bladder to the sides of the prostate.
The prostate consists of three lobes : two lateral and a middle lobe.
The tivo lateral lobes are of equal size, separated behind by a deep notch, and
marked by a slight furrow upon their upper and lower surface, which indicates
the bi-lobed condition of the organ in some animals.
The third or middle lobe, is a small transverse band occasionally a rounded
or triangular prominence, placed between the two lateral lobes, at the under
and posterior part of the organ. It lies immediately beneath the neck of the
bladder, behind the commencement of the urethra, and above the ejaculatory
ducts. Its existence is not constant ; but it is occasionally found at an early
period of life, as well as in adults, and in old age. In advanced life this, or some
other portion of the prostate, often becomes considerably enlarged, and projects
into the bladder, so as to impede the passage of the urine. According to Dr.
Messer's researches conducted at Greenwich Hospital,^ it would seem that such
obstruction exists in 20 per cent, of all prostates over sixty years of age.
The prostate gland is perforated by the urethra and common seminal ducts.
The urethra usually lies about one-third nearer its upper than its lower surface ;
occasionally, the prostate surrounds the lower three-fourths of this tube, and
more rarely the urethra runs through the lower instead of the upper part of the
gland. The ejaculatory ducts pass forwards obliquely through a conical canal,
situated in the lower part of the prostate, and open into the prostatic portion ot
the urethra.
Structure. The prostate is inclosed in a thi-n but firm fibrous capsule, distinct
from that derived from the posterior layer of the deep perineal fascia, and sepa-
rated from it by a plexus of veins. Its substance is of a pale reddish-gray color,
' Med. Chir. Trans., vol. xliii. p. 152.
(855)
856 MALE GENERATIVE ORGANS.
very friable, but of great density. It consists of glandular substance and mus-
cular tissue.
The glandular substance is composed of numerous follicular pouches opening
into elongated canals, which join to form from twelve to twenty small excretory
ducts. The follicles are connected together by areolar tissue, supported by pro-
longations from the fibrous capsule, and inclosed in a delicate capillary plexus.
The epithelium lining the canals is columnar, whilst that in the terminal vesicles
is of the squamous variety.
The muscular tissue of the prostate is arranged in the form of circular bands
round the urethra; it is continuous behind with the circular fibres of the sphincter
vesicae, and in front with the circular fibres of the urethra. The muscular fibres
are of the involuntary kind. The prostatic ducts open into the floor of the
prostatic portion of the urethra.
Vessels and Nerves. The arteries supplying the prostate are derived from the
internal pudic, vesical, and hemorrhoidal. Its veins form a plexus around the
sides and base of the gland ; they communicate in front with the dorsal vein of
the penis, and terminate in the internal iliac vein. The nerves are derived from
the hypogastric plexus.
The Prostatic Secretion is a milky fluid, having an acid reaction, and pre-
senting, on microscopic examination, molecular matter, the squamous and colum-
nar forms of epithelium, and granular nuclei. In old age, this gland is liable to
be enlarged, and its ducts are often filled with innumerable small concretions,
of a brownish-red color, and of the size of a millet seed, composed of carbonate
of lime and animal matter.
Cowper's Glands.
Cowper's Glands are two small rounded and somewhat lobulated bodies, of a
yellowish color, about the size of peas, placed beneath the fore part of the mem-
branous portion of the urethra, between the two layers of the deep perineal
fascia. They lie close behind the bulb, and are inclosed by the transverse fibres
of the Compressor urethras muscle. Each gland consists of several lobules, held
together by a fibrous investment. The excretory duct of each gland, nearly an
inch in length, passes obliquely forwards beneath the mucous membrane, and
opens by a minute orifice on the floor of the bulbous portion of the urethra.
Their existence is said to be constant ; they gradually diminish in size as age
advances.
The Penis,
The Penis is the organ of copulation, and contains in its interior the larger
portion of the urethra. It consists of a root, body, and extremity or glans penis.
The root is broad, and firmly connected to the rami of the pubes by two strong
tapering fibrous processes, the crura, and to the front of the symphysis pubis by
a fil)r(jus membrane, the suspensory ligament.
The c.xtrem/ity^ or glans penis presents the form of an obtuse cone, flattened
from aVjove downwards. At its summit is a vertical fissure, the orifice of the
urethra {meatus urinarius)-. at the back part of this orifice a fold of mucous
membrane passes backwards to the bottom of a depressed raphe, where it is
continuous with the prepuce ; this fold is termed the frsenttm prceptitii. The
base of the glans forms a rounded projecting border, the corona gla,ndis ; and
behind the corona is a deep constriction, the cervix. Upon both of these nume-
rous small lenticular sebaceous glands are found, i\iQ glandnl-se Tysonii^ g. odoriferse.
They secrete a sebaceous matter of very peculiar odor, which probably contains
casoine, and V)ccomcs easily decomposed.
Tlio hody of tlic penis is tlio part botwoon tlio root and extremity. In the
flaccid condition of the organ it is cylindrical, Init when erect has a triangular
PENIS. 857
prismatic form with, rounded angles, the broadest side being turned upward, and
called the dorsum. It is covered by integument remarkable for its thinness, its
dark color, its looseness of connection with the deeper parts of the organ, and
its containing no adipose tissue. At the root of the penis the integument is
continuous with that upon the pnbes and scrotum ; and at the neck of the glans
it leaves the surface, and becomes folded upon itself to form the prepuce.
The internal layer of the prepuce, which also becomes attached to the cervix,
approaches in character to a mucous membrane : it is reflected over the glans
penis, and at the meatus urinarius is continuous with the mucous lining of the
urethra.
The mucous membrane covering the glans penis contains no sebaceous glands;
but projecting from its free surface are a number of small highly sensitive
papillas.
The penis is composed of a mass of erectile tissue, inclosed in three cylindrical
fibrous compartments. Of these, two, the corpora cavernosa, are placed side by
side along the upper part of the organ ; the third, or corpus spongiosum, incloses
the urethra, and is placed below.
The Corpora Cavernosa form the chief part of the body of the penis. They
consist of two fibrous cylindrical tubes, placed side by side, and intimately
connected along the median line for their anterior three-fourths, their posterior
fourth being separated to form the two crura, by which the penis is connected
to the rami of the pubes. Each crus commences by a blunt-pointed process in
front of the tuberosity of the ischiiim; and, near its junction with its fellow,
presents a slight enlargement, named by Kobelt, the hulh of the corpus cavernosum.
Just beyond this point they become constricted, and retain an equal diameter to
their anterior extremity, where they form a single rounded end, which is received
into a fossa in the base of the glans penis. A median groove on the upper sur-
face lodges the dorsal vein of the penis, and the groove on the under surface
receives the corpus spongiosum. The root of the penis is connected to the
symphysis pubis by the suspensory ligament.
Structure. Each corpus cavernosum consists of a strong fibrous envelope,
inclosing a fibrous reticular structure, which contains erectile tissue in its
meshes. It is separated from its fellow by an incomplete fibrous septum.
The fibrous investment is extremely dense, of considerable thickness, and
highly elastic ; it not only invests the surface of the organ, but sends off nume-
rous fibrous bands (traheculse) from its inner surface, as well as from the surface
of the septum, which cross its interior in all directions, subdividing it into a
number of separate compartments, which present a spong}^ structure, in which
the erectile tissue is contained.
The trabecular structure fills the interior of the corpora cavernosa. Its com-
ponent fibres are larger and stronger round the circumference than at the centre
of the corpora cavernosa; they are also thicker behind than in front. The
interspaces, on the contrary, are larger at the centre than at the circumference,
their long diameter being directed transversely ; and they are largest anteriorly.
They are lined by a layer of squamous epithelium.
The fibrous septum forms an imperfect partition between the two corpora
cavernosa ; it is thick and complete behind ; but in front it is incomplete, and
consists of a number of vertical bands of fibrous tissue, which are arranged like
the teeth of a comb, whence the name, septum "pectiniforme ; these bands extend
between the dorsal and the urethral surface of the corpora cavernosa.
The fibrous investment and septum consist of longitudinal bands of white
fibrous tissue, with numerous elastic and muscular fibres. The trabeculse also
consist of white fibrous tissue, elastic fibres, and plain muscular fibres, and
inclose arteries and nerves.
The Corpus Spongiosum incloses the urethra, and is situated in the groove on
the under surface of the corpora cavernosa. It commences posteriorly in front
of the deep perineal fascia, between the diverging crura of the corpora caver-
858
MALE GENERATIVE ORGANS
nosa, wliere it forms a rounded enlargement, the bulb; and terminates, ante-
riorly, in another expansion, the glans penis, which overlaps the anterior
rounded extremity of the corpora cavernosa. The central portion, or body of
the corpus spongiosum, is cylindrical, and tapers slightly from behind forwards.
The hulh varies in size in ditferent subjects; it receives a fibrous investment
from the anterior layer of the deep perineal fascia, and is surrounded by the
Accelerator urinee muscle. The urethra enters the bulb nearer its upper than
its lower surface, being surrounded by a layer of erectile tissue, a thin prolonga-
tion of which is continued backwards round the membranous and prostatic
portions of the canal to the neck of the bladder, lying immediately beneath the
mucous membrane. The portion of the bulb below the urethra presents a
partial division into two lobes, being marked externally by a linear raphe,
whilst internally there projects inwards, for a short distance, a thin fibrous
septum, more distinct in early life.
Structure. The corpus spongiosum consists of a strong fibrous envelope,
inclosing a trabecular structure, which contains in its meshes erectile tissue.
The fibrous envelope is thinner, whiter in color, and more elastic than that of
the corpus cavernosum. The trabeculse are delicate, uniform in size, and the
meshes between them small; their long diameter, for the most part, corre-
sponding with that of the penis. A thin layer of muscular fibres, continuous
behind with those of the bladder, forms part of the outer coat of the corpus
spongiosum.
The erectile tissue consists essentially of an intricate venous plexus, lodged in
the interspaces between the trabeculse. The veins forming this plexus are so
numerous, and communicate so freely with one another, as to present a cellular
appearance when examined by means of a section ; their walls are extremely
thin, and lined by squamous epithelium. The veins are smaller in the glans -
penis, corpus spongiosum, and circumference of the corpora cavernosa, than in
the central part of the latter, where they are of large size, and much dilated.
They return the blood by a series of vessels, some of which emerge in consider-
able numbers from the base of the glans penis, and converge on the dorsum of
the organ to form the dorsal vein ; others pass out on the upper surface of the
corpora cavernosa, and join the dorsal vein; some emerge from the under
surface of the corpora cavernosa, and, receiving branches from the corpus
spongiosum, wind round the sides of the penis to terminate in the dorsal vein;
but the greater number pass out at the root of the penis, and join the prostatic
plexus and pudendal veins.
Fiir. 497.
^mvi
From the poriphoral portion of tlio (■•irjms eavonioHuiii ponis ntulcr a low mapnifyiiicr powor. 1, a notwork knowa
aH tho Huporflclal : b, the deop. 2, couuoction ol' llio artoiial twiya (a) with tho canals of tlio dcopor cortical network.
(Copied from liangnr.)
The arteries of th.e penis arc derived from the internal pudic. Those supplying
the corpora cavernosa are the arteries of the corpora cavernosa, and branches
COVERINGS OF TESTIS. 859
from tlie dorsal artery of the penis, wliicli perforate the fibrous capsule near the
fore part of the organ. Those to the corpus spongiosum are the arteries of the
bulb. Additional branches are described by Kobelt as arising from the trunk
of the internal pudic: they enter the bulbous enlargements on the corpora
cavernosa and corpus spongiosum. The arteries, on entering the cavernous
structure, divide into branches, which are supported and inclosed by the trabe-
cuhe; some of these branches terminate in a capillary network, which com-
municates with the veins as in other parts; whilst others are more convoluted,
and assume a tendril-like appearance ; hence the name, helicine arteries^ which
was given to these vessels by Muller. The helicine arteries are more abundant
in the back part of the corpora cavernosa and corpus spongiosum; they have
not been seen in the glans penis. The termination of these arteries in the
venous spaces has been long a matter of debate ; but the views of Langer are
those which are now universally adopted. He describes the arteries of the
corpus cavernosum as terminating, some of them (as above), in ordinary capil-
laries. Others run, as somewhat fine arterial twigs (about ^^^th of an inch in
diameter), into the venous network, while the terminal branches of the arteries
open directly into the venous spaces by remarkable funnel-shaped orifices.
There are also capillaries which surround the coats of the large arteries, and
communicate with the venous spaces. This arrangement of vessels is also found
in the bulb of the urethra. In the corpus spongiosum and in the glans, the
arteries communicate with the venous spaces through the intervention of capil-
lary vessels.^
The lymphatics of the penis consist of a superficial and deep set ; the former
terminate in the inguinal glands ; the latter emerge from the corpora cavernosa
and corpus spongiosum, and, passing beneath the pubic arch, join the deep lym-
phatics of the pelvis.
The nerves are derived from the internal pudic nerve and the hypogastric
plexus. On the glans and bulb some filaments of the cutaneous nerves have
Pacinian bodies connected with them.
The Testes and their Coveeings.
The Testes are two small glandular organs, which secrete the semen; they
are situated in the scrotum, being suspended by the spermatic cords. At an
early period of foetal life, the testes are contained in the abdominal cavity,
behind the peritoneum. Before birth, they descend to the inguinal canal, along
which they pass with the spermatic cord, and, emerging at the external abdo-
minal ring, they descend into the scrotum, becoming invested in their course
by numerous coverings derived from the serous, muscular, and fibrous layers
of the abdominal parietes, as well as by the scrotum. The coverings of the
testis are, the
Skin ) Q -
Dartos \ Scrotum.
Intercolumnar, or External spermatic fascia.
Cremaster muscle.
Infundibuliform, or Fascia propria (Internal spermatic fascia).
Tunica vaginalis.
The Scrotum is a cutaneous pouch, which contains the testes and part of the
spermatic cords. It is divided into two lateral halves, by a median line, or
raphe, which is continued forwards to the under surface of the penis, and back-
wards along the middle line of the perineum to the anus. Of these two lateral
portions the left is longer than the right, and corresponds with the greater
length of the spermatic cord on the left side. Its external aspect varies under
■ See Frey's Manual of Histology for a summary of Langer's description of these vessels.
860 MALE GENERATIVE ORGANS.
different circumstances : thus, under tlie influence of warmth, and in old and
debilitated persons, it becomes elongated and flaccid ; but, under the influence
of cold, and in the young and robust, it is short, corrugated, and closely applied
to the testes.
The scrotum consists of two laj^ers, the integument and the dartos.
The integument is very thin, of a brownish color, and generally thrown into
folds or rugge. It is provided with sebaceous follicles, the secretion of which
has a peculiar odor, and is beset with thinly scattered, crisp hairs, the roots of
which are seen through the skin.
The dartos is a thin layer of loose reddish tissue, endowed with contractility;
it forms the proper tunic of the scrotum, is continuous, around the base of the
scrotum, with the superficial fascia of the groin, perineum, and inner side of the
thighs, and sends inwards a distinct septum, septum scroti., which divides it into
two cavities for the two testes, the septum extending between the raphe and the
under surface of the penis, as far as its root.
The dartos is closely united to the skin externally, but connected with the
subjacent parts by delicate areolar tissue, upon which it glides with the greatest
facility. The dartos is very vascular, and consists of a loose areolar tissue, con-
taining unstriped muscular fibre. Its contracility is slow, and excited by cold
and mechanical stimuli, but not by electricity.
The inter columnar fascia is a thin membrane, derived from the margin of the
pillars of the external abdominal ring, during the descent of the testis in the
foetus, being prolonged downwards around the surface of the cord and testis. It
is separated from the dartos by loose areolar tissue, which allows of considerable
movement of the latter upon it, but is intimately connected with the succeeding
layer.
The cremasteric fascia consists of scattered bundles of muscular fibres {Cre-
m^aster muscle)., derived from the lower border of the internal oblique mascle,
during the descent of the testis.
The fascia propria is a thin membranous layer, which loosely invests the
surface of the cord It is a continuation downwards of the infundibuliform
process of the fascia transversalis, and is also derived during the descent of the
testis, in the foetus.
The tunica vaginalis is described with the proper covering of the testis. A
more detailed account of the other coverings of the testis will be found in the
description of the surgical anatomy of inguinal hernia.
Vessels and Nerves. The arteries supj^lying the coverings of the testis are :
the superficial and deep external pudic, from the femoral ; the superficial peri-
neal branch of the internal pudic ; and the cremasteric branch from the epigas-
tric. Tlie veins follow the course of the corresponding arteries. The lymphatics
terminate in the inguinal glands. The 7ierves are : the ilio-inguinal and ilio-
hypogastric branches of the lumbar plexus, the two superficial perineal branches
of the internal pudic nerve, the infei'ior pudendal branch of the small sciatic
nerve, and tlie genital branch of the genito-crural nerve.
The SrERMATic Cord extends from the internal abdominal ring, where the
structures of which it is composed converge, to the back part of the testicle. It
is composed of arteries, veins, lymphatics, nerves, and the excretory duct of the
testicle. These structures are connected together by areolar tissue, and invested
by tlic fascite brought down by the testicle in its descent. In the abdominal
Avail the cord passes obli(]^ucly along the inguinal canal, lying at first beneath
the Internal oblique, and upon the fascia transversalis ; but nearer the pubes, it
rests upon Poupart's ligament, having the aponeurosis of the External oblique
in front of it, and the conjoined tendon behind it. It then esca]")es at the exter-
nal ring, ami descends nearly vertically into the scrotum. The left cord is
ratlier longer than the right, consequently the left testis hangs somewhat lower
than its fellow.
The arteries of the cord arc : the spermatic, from the aorta ; the artery of the
TESTES. 861
vas deferens, from the superior vesical ; and the cremasteric, from the epigastric
artery.
The spermatic artery supplies the testicle. On approaching the gland, it gives
off some branches which supply the epididymis, and others which perforate the
tunica albuginea behind, and spread out on its inner surface, or pass through
the fibrous septum in its interior, to be distributed on the membranous septa
between the lobes.
The artery of the vas deferens is a long slender vessel, which accompanies the
vas deferens, ramifying upon the coats of that duct, and anastomosing with the
spermatic artery near the testis.
The cremasteric branch from the epigastric supplies the Cremaster muscle,
and other coverings of the cord.
The spermatic veins leave the back part of the testis, and, receiving branches
from the epididymis, unite to form a plexus {jpanpiniforvn plexus)^ which forms
the chief mass of the cord. They pass up in front of the vas deferens, and unite
to form a single trunk, which terminates, on the right side, in the inferior vena
cava, on the left side, in the left renal vein.
The lymphatics are of large size, accompany the bloodvessels, and terminate
in the lumbar glands.
The nerves are the spermatic plexus from the sympathetic. This plexus is
derived from the renal and aortic plexuses, joined by filaments from the hypo-
gastric plexus which accompany the artery of the vas deferens.
Testes.
The Testes are suspended in the scrotum by the spermatic cords. Each gland
is of an oval form, compressed laterally and behind and having an oblique posi-
tion in the scrotum ; the upper extremity being directed forwards and a little
outwards; the lower, backwards and a little inwards; the anterior convex
border looks forwards and downwards, the posterior or straight border, to which
the cord is attached, backwards and upwards.
The anterior and lateral surfaces, as well as both extremities of the organ, are
convex, free, smooth, and invested by the tunica vaginalis. The posterior
border, to which the cord is attached, receives only a partial investment from
that membrane. Lying upon the outer edge of this border, is a long, narrow,
flattened body, named, from its relation to the testis, the epididymis (SiiSn/ioj,
testis). It consists of a central portion, or body, an upper enlarged extremity,
the globus major.^ or head ; and a lower pointed extremity, the tail, or globus
minor. The globus major is intimately connected with the upper end of the
testicle by means of its efferent ducts ; and the globus minor is connected with
its lower end by cellular tissue, and a reflection of the tunica vaginalis. The
outer surface and upper and lower ends of the epididymis are free and covered
by serous membrane ; the body is also completely invested by it, excepting
along its posterior border, and connected to the back of the testis l3y a fold of
the serous membrane. Attached to the upper end of the testis, or to the epi-
didymis, is a small pedunculated body, the use of which is unknown. When
the testicle is removed from the body the position of the vas deferens, on its
posterior and inner side, marks the side to which the gland has belonged.
Size and Weight. The average dimensions of this gland are from one and a
half to two inches in length, one inch in breadth, and an inch and a quarter in
the antero-posterior diameter; and the weight varies from six to eight drachms,
the left testicle being a little the larger. The testis is invested by three tunics,
the tunica vaginalis, tunica albuginea, and tunica vasculosa.
The Tunica Vaginalis is the serous covering of the testis. It is a pouch of
serous membrane, derived from the peritoneum during the descent of the testis
in the foetus, from the abdomen into the scrotum. After its descent, that portion
of the pouch which extends from the internal ring to near the upper part of the
862
MALE GENERATIVE ORGANS.
Fig. 498.— The Testis m situ, tlie
Tunica Vaginalis having been
laid open.
Artery
of Cord
Tim'ra Vrtglnalh
gland becomes obliterated, the lower portion remaining as a sbnt sac, whicli
invests tlie outer surface of the testis, and is reflected on the internal surface of
the scrotum; hence it maj be described as consisting of a visceral and parietal
portion.
The visceral portion [tunica vaginalis propria) covers the outer surface of the
testis, as well as the epididymis, connecting the latter to the testis by means of
a distinct fold. From the posterior border of the
gland, it is reflected on to the internal surface of
the scrotum.
The p)arietal portion of the serous membrane
{tunica vaginalis reflexd) is far more extensive
than the visceral portion, extending upwards, for
some distance in front, and on the inner side of
the cord, and reaching below the testis. The
inner surface of the tunica vaginalis is free,
smooth, and covered by a layer of squamous epi-
thelium. The interval between the visceral and
parietal layers of this membrane constitutes the
cavity of the tunica vaginalis.
The Tunica Albuginea is the fibrous covering
of the testis. It is a dense fibrous membrane, of
a bluish- white color, composed of bundles of white
fibrous tissue, which interlace in every direction.
Its outer surface is covered by the tunica vagi-
nalis, except along its posterior border, and at the
points of attachment of the epididymis ; hence
the tunica albuginea is usually considered as a
fibro-serous membrane, like the dura mater and
pericardium. This membrane surrounds the
glandular structure of the testicle, and, at its posterior and upper border, is
reflected into the interior of the gland, forming an incomplete vertical septum
called the mediastinum testis (corpus Highmorianum).
The m^ediastinwrn testis extends from the upper, nearly to the lower border of
the gland, and is wider above than below. From the front and sides of this
septum, numerous slender fibrous cords (traheculse) are given off, which pass to
be attached to the inner surface of the tunica albuginea : they serve to maintain
the form of the testis, and join with similar cords given off from the inner sur-
face of the tunica albuginea, to form spaces which inclose the separate lobules
of the organ. The mediastinum supports the vessels and ducts of the testis in
their passage to and from the substance of the gland.
The Tunica Vasculosa {pia mater testis) is the vascular layer of the testis, con-
sisting of a plexus of bloodvessels, held together by a delicate areolar tissue.
It covers the inner surface of the tunica albuginea, sending off numerous pro-
cesses between the lobules, which are supported by the fibrous prolongations
from the mediastinum testis,
Structure. The glandular structure of the testis consists of numerous lobules
{lohuli testis). Their number, in a single testis, is estimated by Bcrres at 250,
and by Krause at 400. They differ in size according to their position, those in
the middle of the gland being larger and longer. The lobules are conical in
shape, the base being directed towards the circumference of the organ, the apex
towards the mediastinum. Each lobule is contained in one of the intervals
between the fibrous cords and vascular processes, which extend between the
mediastinum testis and the tunica albuginea, and consists of from one to three,
or more, minute convohitcd tubes, the tubuU seminiferi. The tubes may be
separately unravelled, by careful dissection under water, and may be seen to
commence citlior by free c;r'(;al ends, or by aniistomotio loops. The total number
of tubes is considered by Munro to be about c>00, and the length of each about
TESTES.
8f53
Fisr. 499.— Vertical Section of the
Testicle to show the arrange-
ment of the Ducts.
sixteen feet ; bj Lautli, tlieir number is estimated at 840, and tlieir average
lengtli two feet and a quarter. Their diameter varies from g^gtli to Yjfjtli of an
inch. The tubuli are pale in color in early life, but, in old age, they acquire a
deep yellow tinge, from containing much fatty matter. They consist of a base-
ment membrane, lined by epithelium consisting of nucleated glandular cor-
puscles, and are inclosed in a delicate plexus of capillary vessels. In the apices
of the lobules, the tubuli become less convoluted, assume a nearly straight
course, and unite together to form from twenty to thirty larger ducts, of about
^'^th of an inch in diameter, and these, from their straight course, are called
vasa recta.
The vasa recta enter the fibrous tissue of the mediastinum, and pass upwards
and backwards, forming, in their ascent, a close network of anastomosing tubes,
with, exceedingly thin parietes ; this constitutes
the rete testis. At the upper end of the medi-
astinum, the vessels of the rete testis terminate
in from twelve to fifteen or twenty ducts, the vasa
efferentia : they perforate the tunica albuginea,
and carry the seminal fluid from the testis to the
epididymis. Their course is at first straight ;
they then become enlarged, and exceedingly con-
voluted, and form a series of conical masses, the
coni vasculosis which, together, constitute the
globus major of the epididymis. Each cone con-
sists of a single convoluted duct, from six to eight
inches in length, the diameter of which gradually
decreases from the testis to the epididymis. Oppo-
site the bases of the cones, the efferent vessels
open at narrow intervals into a single duct, which
constitutes, by its complex convolutions, the
body and globus minor of the epididymis. When
the convolutions of this tube are unravelled, it
measures upwards of twenty feet in length, and
increases in breadth and thickness as it approaches
the vas deferens. The convolutions are held to-
gether by fine areolar tissue, and by bands of
fibrous tissue. A long narrow tube, the vascu-
lum aherrans of Haller, is occasionally found con-
nected with the lower part of the canal of the
epididymis, or with the commencement of the vas deferens. It extends up into
the cord for about two or three inches, Avhere it terminates by a blind extremity,
which is occasionally bifurcated. Its length varies from an inch and a half to
fourteen inches, and sometimes it becomes dilated towards its extremity : more
commonly, it retains the same diameter throughout. Its structure is similar to
that of the vas deferens. Occasionally, it is found unconnected with the epi-
didymis.
Tlie Vas Deferens, the excretory duct of the testis, is the continuation of the
epididymis. Commencing at the lower part of the globus minor, it ascends
along the posterior and inner side of the testis and epididymis, and along the
back part of the spermatic cord, through the spermatic canal to the internal
abdominal ring. From the ring it descends into the pelvis, crossing the external
iliac vessels, and curves rou.nd the outer side of the epigastric artery : at the
side of the bladder, it arches backwards and downwards to its base, crossing
outside the obliterated hypogastric artery, and to the inner side of the ureter.
At the base of the bladder, it lies between that viscus and the rectum, running
along the inner border of the vesicula seminalis. In this situation it becomes
enlarged and sacculated : and, becoming narrowed, at the base of the prostate,
unites with the duct of the vesicula seminalis to form the ejaculatory duct. The
864
MALE GENERATIVE ORGANS.
vas deferens presents a liard and cord-like sensation to tlie fingers ; it is about
two feet in length, of cjdindrical form, and about a line and a quarter in dia-
meter. Its walls are of extreme density and thickness, measuring one-tliird of
a line ; and its canal is extremely small, measuring about half a line.
In Structure^ the vas deferens consists of three coats : 1. An external, or
cellular coat; 2. A muscular coat, which is thick, dense, elastic, and consists of
two longitudinal, and an intermediate circular layer of muscular fibres ; 3. An
internal, or mucous coat, which is pale, and arranged in longitudinal folds ; its
epithelial covering is of the columnar variety.
Vesicul^e Semiistales.
The Seminal Vesicles are two lobulated membranous pouches, placed between
the base of the bladder and the rectum, serving as reservoirs for the semen, and
secreting some fluid to be added to that of the testicles. Each sac is somewhat
pyramidal in form, the broad end being directed backwards and the narrow end
forwards towards the prostate. They measure about two and a half inches in
length, about five lines in breadth, and about two or three lines in thickness.
They vary, however, in size, not only in different individuals, but also in the
same individual on the two sides. Their tipper surface is in contact with the
base of the bladder, extending from near the termination of the ureters to the
base of the prostate gland. Their under surface rests upon the rectum, from
which they are separated by the recto-vesical fascia. Their 'posterior extremities
diverge from each other. Their anterior extremities are pointed, and converge
towards the base of the prostate gland, where each joins with the corresponding
vas deferens to form the ejaculatory duct. Along the inner margin of each
Fin:. 500.-
-Base of the Bladder, with the Vasa Deferentia
and Vesiculje Seminales.
Ji„jlli:jar,l
vc.sicula runs tlic enlarged and convoluted vas deferens. The inner border of
the vcsicuko, and the corresponding vas deferens, form the lateral boundary of
ii triangular space, limited behind by the recto-vcsical peritoneal fold; the por-
tion of the bladder included in this space rests on the rectum, and corresponds
with the trigonum vesicui in its interior.
_ Slructvrcs. Each vcsicula consists of a single tube, coiled npon itself, and
giving oft' several irregular cu3cal diverticula; the separate coils, as well as the
DESCENT OF THE TESTES. 8Go
diverticula, being connected together bj fibrous tissue. AVhen uncoiled, tliis
tube is about tlie diameter of a quill, and varies in length from four to six
inches; it terminates posteriorly in a cul-de-sac; its anterior extremity becomes
constricted into a narrow straight duct, which joins on its inner side with the
corresponding vas deferens, and forms the ejaculatory duct.
The ejaculatory ducts, two in number, one on each side, are formed by the
junction of the duct of the vesicula seminalis with the vas deferens. Each duct
is about three-quarters of an inch in length ; it commences at the base of the
prostate, and runs forwards and upwards in a canal in its substance, and along
the side of the utriculus, to terminate by a separate slit-like orifice upon or
within the margins of the sinus pocularis. The ducts diminish in size, and
converge towards their termination.
Structure. The vesiculse seminales are composed of three coats: an external
or fihro-cellular, derived from the recto- vesical fascia; sl middle oi Jihrous coat,
which is firm, dense, fibrous in structure, somewhat elastic, and contains, accord-
ing to E. H. Weber, muscular fibres; and an internal or mucous coat, which is
pale, of a whitish-brown color, and presents a delicate reticular structure, like
that seen in the gall-bladder, but the meshes are finer. The epithelium is
squamous. The coats of the ejaculatory ducts are extremely thin, the outer
fibrous layer being almost entirely lost after their entrance into the prostate, a
thin layer of muscular fibres and the mucous membrane forming the only con-
stituents of the tubes.
Vessels and Nerves. The arteries supplying the vesicul^B seminales are derived
from the inferior vesical and middle hemorrhoidal. The veins and lymphatics
accompany the arteries. The nerves are derived from the hypogastric plexus.
The Semen is a thick, whitish fluid, having a peculiar odor. It consists of a
fluid, the liquor seminis, and solid particles, the seminal granules, and sperma-
tozoa.
The liquor seminis is transparent, colorless, and of an albuminous composition,
containing particles of squamous and columnar epithelium, with oil-globules
and granular matter floating in it, besides the above-mentioned solid elements.
The seminal granules are round finely-granular corpuscles, measuring ^j^'g^th
of an inch in diameter.
The spermatozoa, or spermatic filaments, are the essential agents in producing
fecundation. They are minute elongated particles, consisting of a small flattened
oval extremity or body, and a long slender caudal filament. A small circular
spot is observed in the centre of the body, and at its point of connection with
the tail there is frequently seen a projecting rim or collar. The movements of
these bodies are remarkable, and consist of a lashing or undulatory motion of
the tail.
Descent of the Testes.
The testes, at an early period of foetal life, are placed at the back part of the
abdominal cavity, behind the peritoneum, in front, and a little below the
kidneys. The anterior surface and sides are invested by peritoneum: the blood-
vessels and efferent ducts are connected with their posterior surface; and
attached to the lower end is a peculiar structure, the gubernaculum testis,
which is said to assist in their descent.
The G'uhernaculum Testis attains its full development betweeen the fifth and
sixth months; it is a conical-shaped cord, attached above to the lower end of
the epididymis, and below to the bottom of the scrotum. It is placed behind
the peritoneum, \y\ng upon the front of the Psoas muscle, and completely filling
the inguinal canal. It consists of a soft transparent areolar tissue within, which
often appears partially hollow, surrounded by a layer of striped muscular fibres,
the Cremaster, which ascends upon this body to be attached to the testis.
According to Mr. Curling, the gubernaculum, as well as these muscular fibres,
55
^
866 MALE GENERATIVE ORGANS.
divides below into tliree processes : the external and broadest process is con-
nected with Poupart's ligament in the inguinal canal; the middle process
descends along the inguinal canal to the bottom of the scrotum, where it joins
the dartos ; the internal one is firmly attached to the os pubis and sheath of the
Eectus muscle; some fibres, moreover, are reflected from the Internal .oblique
on to the front of the gubernaculum. Up to the fifth month, the testis is
situated in the lumbar region, covered in front and at the sides by peritoneum,
and sapported in its position by a fold of that membrane, called the mesorchium ;
between the fifth and sixth months the testis descends to the iliac fossa, the
gubernaculum at the same time becoming shortened; during the seventh month,
It enters the internal abdominal ring, a small pouch of peritoneum [processus
vaginalis) preceding the testis in its course through the canal. By the end of
the eighth month, the testis has descended into the scrotum, carrying down
with it a lengthened pouch of peritoneum, which communicates by its upper
extremity with the peritoneal cavity. Just before birth, the upper part of the
pouch usually becomes closed, and' this obliteration extends gradually down-
wards to within a short distance of the testis. The process of peritoneum
surrounding the testis which is now entirely cut off from the general peritoneal
cavity, constitutes the tunica vaginalis}
Mr. Curling believes that the descent of the testis is efifected by means of the
muscular fibres of the gubernaculum ; those fibres which proceed from Poupart's
ligament and the Obliquus internus are said to guide the organ into the inguinal
canal ; those attached to the pubis draw it below the external abdominal ring ;
and those attached to the bottom of the scrotum complete its descent. During
the descent of the organ these muscular fibres become gradually everted, forming
a muscular layer, which becomes placed external to the process of the perito-
neum, surrounding the gland and spermatic cord, and constitutes the Cremaster.
In the female, a small cord, corresponding to the gubernaculum in the male,'
descends to the inguinal region, and ultimately forms the round ligament of the
uterus. A pouch of peritoneum accompanies it along the inguinal canal, analo-
gous to the processus vaginalis in the male : it is called the canal of Nuck.
' The obliteration of the process of pcritonenm which accompanips the cord, and is hence called
the /K??7'cM/a?' proce.s.s, is often incomplete. For an account of the various conditions produced
by such incomplete obliteration (which are of great importance in the pathological anatomy of
Inguinal Hernia), the student is referred to the "Essay on Hernia," by Mr. Birkett, in "A System
of Surgery," edited by T. Holmes, vol. iv.
Female Organs of Generation.
The External Organs of Generation in the female are the mens Veneris, the
labia majora and minora, the clitoris, the meatus urinarius, and the orifice of
the .vagina. The term "vulva" or "pudendum," as generally applied, includes
all these parts.
The mons Veneris is the rounded eminence in front of the pubes, formed by
a collection of fatty tissue beneath the integument. It surmounts the vulva,
and is covered with hair at the time of puberty.
Fig. 501. — The Vulva. External Female Organs of Generation.
The labia majora are two prominent longitudinal cutaneous folds, extending
downwards from the mons Veneris to the anterior boundary of the perineum,
and inclosing an elliptical fissure, the common urino-sexual opening. Each
labium is formed externally of integument covered with hair ; internally, of
mucous membrane, which is continuous with the genito- urinary mucous tract;
and between the two, of a considerable quantity of areolar tissue, fat and a tissue
(867)
868 FEMALE ORGANS OF GENERATION.
resembling tlie dartos of tlae scrotum, besides vessels, nerves, and glands. Tlie
labia are thicker in front than behind, and joined together at each extremity,
forming the anterior and posterior commissures. The interval left between the
posterior commissure and tlie margin of the anus is about an inch in length,
and constitutes the perineum. Just within the posterior commissure is a small
transverse fold, ihe, fraenuluTYi -pudendi ot fourchette^ which is commonly ruptured
in the first parturition, and the space between it and the commissure is called
the fossa navicularis. The labia are analogous to the scrotum in the male.
The labia minora or nympli-de are two small folds of mucous membrane situ-
ated within the labia majora, extending from the clitoris obliquely downwards
and outwards for about an inch and a half on each side of the orifice of the
vagina, on the sides of which they are lost. They are continuous externally
with the labia majora, internally with the inner surface of the vagina. As they
converge towards the clitoris in front, each labium divides into two folds, which
surround the glans clitoridis, the superior folds uniting to form the prse2:)utmm
ditoridis^ the inferior folds being attached to the glans, and forming the frsenuoii.
The nymphse are composed of mucous membrane, covered by a thin epithelial
layer. They contain a plexus of vessels in their interior, and are provided with
numerous large mucous crypts which secrete abundance of sebaceous matter.
The clitoris is an erectile structure, analogous to the corpora cavernosa of the
penis. It is situated beneath the anterior commissure, partially hidden between
the anterior extremities of the labia minora. *It is an elongated organ, connected
to the rami of the pubes and ischia on each side by two crura; the body is
short and concealed beneath the labia ; the free extremity, or glans clitoridis, is
a small rounded tubercle, consisting of spongy erectile tissue, and highly sensi-
tive. The clitoris consists of two corpora cavernosa, composed of erectile tissue
inclosed in a dense layer of fibrous membrane, united together along their inner
surfaces by an incomplete fibrous pectiniform septum. It is provided, like the
penis, with a suspensory ligament, and with two small muscles, the Brectores
clitoridis, which are inserted into the crura of the corpora cavernosa.
Between the clitoris and the entrance of the vagina is a triangular smooth
surface, bounded on each side by the nymphs : this is the vestibule.
The orifice of the urethra (meatus vrinarius)^ is situated at the back part of
the vestibule, about an inch below the clitoris, and near the margin of the vagina,
surrounded by a prominent elevation of the mucous membrane. BeloAv the
meatus urinarius is the orifice of the vagina, an elliptical aperture, more or less
closed in the virgin, by a membranous fold, the hymen.
The hymen is a thin semilunar fold of mucous membrane, stretched across
the lower part of the orifice of the vagina ; its concave margin being turned
upwards towards the pubes. Sometimes this membrane forms a complete
septum across the orifice of the vagina ; a condition known as imperforate hymen.
Occasionally it forms a circular septum, perforated in the centre by a round
opening; sometimes it is cribriform, or its free margin forms a membranous
fringe, or it may be entirely absent. It may also persist after copulation. The
hymen cannot, consequently, be considered as a test of virginity. Its rupture,
or the rudimentary condition of the membrane above referred to, gives rise to
those small rounded elevations which surround the opening of the vagina, the
caruncuhje m yr/i formes.
Glands of BarlJioline. On cnoh side of the commencement of the vagina is a
round or oblong body, of a rcddisli -yellow color, and of the size of a horse-
bean, analogous to Cowper's gland in llio male. It is called the gland of Bar -
thoh'ne. Each gland opens by means of a long single duct, upon the inner side
of the nymplia3, external to the hymen. Extending from the clitoris, along
cither side of the vestibule, and lying a little behind thcnymphre, are two large
oblong masses, about an inch in length, consisting of a plextis of veins, inclosed
in a thin layer of fibrous membrane. These bodies are narrow in front, rounded
below, and are connected with the crura of the clitoris and rami of the pubes :
FEMALE URETHRA.
8G9
tliey are termed by Kobelt the hulhi vestihuU: and lie considers them analogous
to the bulb of the corpus spongiosum in the male. Immediately in front of
these bodies is a smaller venous plexus, continuous with the bulbi vestibuli
behind, and the glans clitoridis in front : it is called by Kobelt the pars iyiter-
raedia, and is considered by him as analogous to that part of the body of the
corpus spongiosum which immediately succeeds the bulb.
Fig. 502.— Section of Female Pelvis, showing positiou of Viscera.
Bladder.
The Bladder is situated at the anterior part of the pelvis. It is in relation,
in front^ with the os pubis ; behind, with the uterus, some convolutions of the
small intestine being interposed ; its hase lies in contact with the neck of the
uterus, and with the anterior wall of the vagina. The bladder is said to be
larger in the female than in the male,, and is very broad in its transverse
diameter.
Urethra. i
The Urethra is a narrow membranous canal, about an inch and a half in
length, extending from the neck of the bladder to the meatus urinarius. It is
placed beneath the symphysis pubis, embedded in the anterior wall of the vagina;
and its direction is obliquely downwards and forwards, its course being slightly
curved, the concavity directed forwards and upwards. Its diameter, when un-
dilated, is about a quarter of an inch. The urethra perforates the triangular
ligament, precisely as in the male, and is surrounded by the muscular fibres of
the Compressor urethr^e.
Structure. The urethra consists of three coats : muscular, erectile, and
mucous.
870 FEMALE ORGNAS OF GENEEATION.
The muscular coat is continuous with that of the bladder ; it extends the
whole length of the tube, and consists of a thick stratum of circular fibres.
A thin layer of spongy, erectile tissue, intermixed with much elastic tissue,
lies immediately beneath the mucous coat.
The mucous coat is pale, continuous, externally, with that of the vulva, and
internally with that of the bladder. It is thrown into longitudinal folds
one of which, placed along the floor of the canal, resembles the verumontanum
in the male urethra. It is lined by laminated epithelium, which becomes
spheroidal at the bladder. Its external orifice is surrounded by a few mucous
follicles.
The urethra, from not being surrounded by dense resisting structures, as in
the male, admits of considerable dilatation, which enables the surgeon to remove
with considerable facility calculi, or other foreign bodies, from the cavity of the
bladder.
Eectum.
The Rectum is more capacious and less curved in the female than in the
male.
T\\Q first portion extends from the left sacro-iliac symphysis to the middle of
the sacrum. Its connections are similar to those in the male.
The second portion extends to the tip of the coccyx. It is covered in front
by the peritoneum, but only for a short distance, at its upper part : it is in
relation with the posterior walJ of the vagina.
The third portion curves backwards from the vagina to the anus, leaving a
space which corresponds on the surface of the body to the perineum. Its ex-
tremity is surrounded by the Sphincter muscles, and its sides are supported by
the Levatores ani.
The Yagina.
The Yagina is a membranous canal, extending from the vulva to the uterus.
It is situated in the cavity of the pelvis, behind the bladder, and in front of
the rectum. Its direction is curved forwards and downwards, following at first
the line of the axis of the cavity of the pelvis, and afterwards that of the outlet.
It is cylindrical in shape, flattened from before backwards, and its walls arc
ordinarily in contact with each other. Its length is about four inches along its
anterior wall, and between five and six inches along its posterior wall. It is
constricted at its commencement, and becomes dilated near its uterine extremity ;
it surrounds the vaginal portion of the cervix uteri, a short distance from the
OS, and its attachment extends higher up on the posterior than on the anterior
wall of the uterus.
Relations. Its anterior surface is concave, and in relation with the base of the
bladder, and with the urethra. Its posterior surface is convex, and connected
to the anterior wall of the rectum, for the lower three-fourths of its extent, the
upper fourth being separated from that tube by the recto-uterine fold of peri-
toneum, which forms a cul-de-sac between the vagina and rectum. Its sides
give attachment superiorly to the broad ligaments, and inferiorly to the Leva-
tores ani muscles and recto-vesical fascia.
SlruMure. The vagina consists of an external, or muscular coat, a layer of
erectile tissue, and an internal mucous lining.
The muscular coat consists of longitudinal fibres which surround tlic vagina,
and are continuous with the superficial muscular fibres of the uterus. The
strongest fasciculi are those attached to the recto-vesical fascia on each side.
The erectile tissue is inclosed between two layers of fibrous membrane : it is
more abundant at the lower than at the upper part of the vagina.
Tlie mucous memhrane is continuous, above, with that lining the uterus, and,
below with the integument covering the luljia majora. Its inner surface pre-
. THE UTERUS. 871
sents, along tlie anterior and posterior walls, a longitudinal ridge, or raplie,
called the columns of the vagina^ and numerous transverse ridges, or rugge, ex-
tending outwards from the raphe on each side. These rugse are most distinct
near the orifice of the vagina, especially in females before parturition. They
indicate its adaptation for dilatation, and are calculated to facilitate its enlarge-
ment during parturition. The mucous membrane is covered with conical and
filiform papillse, and provided with mucous glands and follicles, which are
especially numerous in its upper part, and around the cervix uteri. The epithe-
lium is of the squamous variety.
The Uterus.
The Uterus is the organ of gestation, receiving the fecundated ovum in its
cavity, retaining and supporting it during the development of the foetus, and
becoming the principal agent in its expulsion at the time of parturition.
In the virgin state it is pear-shaped, flattened from before backwards, and
situated in the cavity of the pelvis, between the bladder and the rectum ; it is
retained in its position by the round and broad ligaments on each side, and
projects into the upper end of the vagina below. Its upper end, or base, is
directed upwards and forwards; its lower end, or apex, downwards and back-
wards, in the line of the axis of the inlet of the pelvis. It therefore forms an
angle with the vagina, since the direction of the vagina corresponds to the axis
of the cavity and outlet of the pelvis. The uterus measures about three inches
in length, two in breadth at its upper part, and an inch in thickness, and it
weighs from an ounce to an ounce and a half.
The fundus is the upper broad extremity of the organ : it is convex, covered
by peritoneum, and placed on a line below the level of the brim of the pelvis.
The hody gradually narrows from the fundus to the neck. Its anterior surf ace
is flattened, covered by peritoneum in the upper three-fourths of its extent, and
separated from the bladder by some convolutions of the small intestine : the
lower fourth is connected with the bladder. Its -posterior surface is convex,
covered by peritoneum throughout, and separated from the rectum by some
convolutions of the intestine. Its lateral margins are concave, and give attach-
ment to the Fallopian tube above, the round ligament below and in front of
this, and the ligament of the ovary behind and below both of these structures.
The cervix is the lower rounded and constricted portion of the uterus : around
its circumference is attached the upper end of the vagina, which extends up-
wards a greater distance behind than in front.
At the vaginal extremity of the uterus is a transverse aperture, the os uteris
bounded by two lips, the anterior of which is thick, the posterior narrow and
long.
Ligaments. The ligaments of the uterus are six in number : two anterior,
two posterior, and two lateral. They are formed of peritoneum.
The two anterior liganfients [vesicO'Uterine\ are two semilunar folds, which pass
between the neck of the uterus and the posterior surface of the bladder.
The two -posterior ligam,ents {recto-uterine\ pass between the sides of the uterus
and rectum.
The two lateral or hroad ligam.ents pass from the sides of the uterus to the
lateral walls of the pelvis, forming a septum across the pelvis, which divides
that cavity into two portions. In the anterior part are contained the bladder,
urethra, and vagina; in the posterior part, the rectum.
The cavity of the uterus is small in comparison with the size of the organ:
that portion of the cavity, which corresponds to the body is triangular, flattened
from before backwards, so that its walls are closely approximated, and having
its base directed upwards towards the fundus. At each superior angle is a
funnel-shaped cavity, which constitutes the remains of the division of the body
of the uterus into two cornua; and at the bottom of each cavity is the minute
872 FEMALE ORGANS OF GENERATION.
orifice of the Fallopian tube. At tlie inferior angle of the uterine cavity is a
small constricted opening, the internal orifice (ostium internum), which leads
into the cavity of the cervix. The cavity of the cervix is somewhat cylindrical,
flattened from before backwards, broader at the middle than at either extremity,
and communicates, below, witii the vagina. Each wall of the canal presents a
longitudinal column, from which proceed a number of small oblique columns,
giving the appearance of branches from the stem of a tree, and hence the name
arhor vitse uterinus applied to it. These folds usually become very indistinct
after the first labor.
Structure. The uterus is composed of three coats : an external serous coat, a
middle or muscular layer, and an internal mucous coat.
The serous coat is derived from the peritoneum ; it invests the fundus and the
whole of the posterior surface of the body of the uterus ; but only the upper
three-fourths of its anterior surface.
The muscular coat forms the chief bulk of the substance of the uterus. In the
unimpregnated state, it is dense, firm, of a grayish color, and cuts almost like
cartilage. It is thick opposite the middle of the body and fundus, and thin at
the orifices of the Fallopian tu.bes. It consists of bundles of unstriped muscular
fibres, disposed in layers, intermixed with areolar tissue, bloodvessels, lymphatic
vessels and nerves. In the impregnated state, the muscular tissue becomes more
prominently developed, and is disposed in three layers : external, middle, and
internal.
The external layer is placed beneath the peritoneum, disposed as a thin plane
on the anterior and posterior surfaces. It consists of fibres, which pass trans-
versely across the fundus, and, converging at each superior angle of the uterus,
are continued on the Fallopian tubes, the round ligament, and ligament of the
ovary; some passing at each side into the broad ligament, and others running .
backwards from the cervix into the recto-uterine ligaments.
The middle layer of fibres presents no regularity in its arrangement, being
disposed longitudinally, obliquely, and transversely.
The internal, or deep layer, consists of circular fibres arranged in the form of
two hollow cones, the apices of which surround the orifices of the Fallopian
tubes, their bases intermingling with one another on the middle of the body of
the uterus. At the cervix these fibres are disposed transversely.
The raucous memhrane is thin, smooth, and closely adherent to the subjacent
tissue. It is continuous, through the fimbriated extremity of the Fallopian
tubes, with the peritoneum ; and, through the os uteri, with the mucous mem-
brane lining the vagina.
In the body of the uterus, it is smooth, soft, of a reddish color, lined by
columnar-ciliated epithelium, and presents, when viewed with a lens, the orifices
of numerous tubular follicles arranged perpendicularly to the surface. They are
of small size in the unimpregnated uterus, but shortly after impregnation they
are enlarged, elongated, presenting a contorted or waved appearance towards
their closed extremities, which occasionally dilate into two or three sacculated
extremities. The circular orifices of these glands may be seen on the inner
surface of the mucous membrane, many of which during the early period of
pregnancy arc surrounded by a whitish ring formed of c])ithclium which lines
the follicles. In the iiii])rcgnated uterus, the epithelium loses its ciliated char-
acter.
In the cervix the rriufous mombrnnc between the rugrc and around the os
uteri is provided with numerous mucous follicles and glands. ^J'iie small, trans-
parent, vesicuhir clevatifms, so often found within the os and cervix uteri, are
due to closure of tlic mouths of these follicles, and tlieir distension with their
proper secretion. Thfv nre called WxQovula of Nahotli,. The mucous membrane
covering the lower liiili' oC the cervix presents numerous papillo3,
Vessfls and Nervrs. 'J'lic arteries of the uterus are the uterine, from the
internal iliac ; and the ovarian, from the aorta. They arc remarkable for their
APPENDAGES OF THE UTERUS. 873
tortuous course in the substance of the organ, and for their frequent anastomo-
ses. The veins are of large size, and correspond with the arteries. In the
impregnated uterus these vessels are termed the uterine sinuses^ consisting of
the lining membrane of the veins adhering to the walls of canals channelled
through the substance of the uterus. They terminate in the uterine plexuses.
The lymphatics are of large size in the impregnated uterus, and terminate in
the pelvic and lumbar glands. The nerves are derived from the inferior hypo-
gastric and spermatic plexuses, and from the third and fourth sacral nerves.
The form, size, and situation of the uterus vary at different jieriods of life and under different
circumstances.
In thefcetas, the uterus is contained in the abdominal cavity, projecting beyond the brim of
the pelvis. The cervix is considerably larger than the body.
At puberty, the uterus is pyriform in shape, and weighs from eight to ten drachms It has
descended into the pelvis, the fundus being just below the level of the brim of this cavity. The
arbor vitae is distinct, and extends to the upper part of the cavity of the organ.
During and after menstruation, the organ is enlarged, and more vascular, its surfatres rounder ;
the OS extei'num is rounded, its labia swollen, and the lining membrane of the body thickened,
softer, and of a darker color.
During Pregnancy, the uterus increases so as to weigh from one pound and a half to three
pounds. It becomes enormously enlarged, and projects into the hypogastric and lower part of
the umbilical regions. This enlargement, which continues up to the sixth month of gestation, is
partially due to increased development of pre-existing and new-formed muscular tissue. The
round ligaments are enlarged, and the broad ligaments become encroached upon by the uterus
making its way between their laminre. 'Die mucous membrane becomes more vascular, its mucous
follicles and glands enlarged ; the rugae and folds in the canal of the cervix becomes obliterated;
the blood and lymphatic vessels as well as the nerves, according to the researches of Dr. Lee,
greatly enlarged.
After Parturition, the uterus nearly regains its usual size, weighing from two to three ounces ;
but its cavity is larger than in the virgin state ; the external orifice is more marked, and assumes
a transverse direction; its edges present a fissured surface; its vessels are tortuous; and its
muscular layers are more defined.
In old age, the uterus becomes atrophied, and paler and denser in texture ; a more distinct
constriction separates the body and cervix. The ostium internum, and, occasionally, the vaginal
orifice, often become obliterated, and its labia almost entirely disappear.
Appendages of the Uterus.
The appendages of the uterus are, the Fallopian tubes, the ovaries and their
ligaments, and the round ligaments. These structures, together with their
nutrient vessels and nerves, and some scattered muscular fibres, are inclosed
between the two folds of peritoneum, which constitute the broad ligaments ;
they are placed in the following order: in front is the round ligament; the
Fallopian tube occupies the free margin of the broad ligament: the ovary and
its ligament are behind and below the latter.
The FaMopian Tubes, or oviducts, convey the ova from the ovaries to the
cavity of the uterus. They are two in number, one on each side, situated in
the free margin of the broad ligament, extending from each superior angle of
the uterus to the sides of the pelvis. Bach tube is about four inches in length ;
its canal is exceedingly minute, and commences at the superior angle of the
uterus by a minute oriiice, the ostium internum, which will hardly admit a fine
bristle; it continues narrow along the inner half of the tube, and then gradually*
widens into a trumpet-shaped extremity, which becomes contracted at its terini-
nation. This orifice is called the ostium abdominale, and communicates with the
peritoneal cavity. Its margins are surrounded by a series of fringe-like pro-
cesses, termed fimhriee, and one of these processes is connected with the outer
end of the ovary. To this part of the tube the name fimhriated extremity is
applied; it is also called morsus diaholi, from the peculiar manner in which it
embraces the surface of the ovary during sexual excitement. In connection
with the fimbriae of the Fallopian tube, or with the broad ligament close to
them, there is frequently a small vesicle or hydatid, floating on a long stalk of
peritoneum.
874
FEMALE ORGANS OF GENERATION.
Structure. The Fallopian tube consists of three coats : serous, muscular, and
mucous.
The external or serous coat is derived from the peritoneum.
The middle muscular coat consists of an external longitudinal and an internal
or circular layer of muscular fibres continuous with those of the uterus.
The internal or mucous coat is continuous with the mucous lining of the uterus,
and at the free extremity of the tube with the peritoneum. It is thrown into
longitudinal folds in the outer part of the tube, which indicate its adaptation
for dilatation, and is covered by columnar ciliated epithelium. This form of
epithelium is also found on the inner and outer surfaces of the fimbriee.
• Fig. 503.— The Uterus and its Appendages. Anterior View.
BrisUe passed through
Fig. 504. — Section of the Ovary of a
Virgin, showing the Stroma and
Graafian Vesicles.
The Ovaries {testes muliehres^ Galen) are analogous to the testes in the male.
They are oval-shaped bodies, of an elongated form, flattened from above down-
wards, situated one on each side of the uterus, in the posterior part of the broad
ligament behind and below the Fallopian tubes. Each ovary is connected, by
its anterior margin, to the broad ligaments; by its inner extremity to the uterus
by a proper ligament, the ligament of the
ovary ; and by its outer end to the fimbriated
extremity of the Fallopian tube by a short
ligamentous cord. The ovaries are of a
whitish color, and present either a smooth or
puckered uneven surface. They are each
about an iucli and a half in length, three-
quarters of an inch in width, and about a
third of an inch thick; and weigh from one
to two drachms. The surfaces and posterior
convex border are free, the anterior straight
border being attached to the broad ligament.
Structure. Tlie ovary is invested by perito-
neum, excepting along its anterior attached
margin ; beneath this, is the proper fibrous
covering of the organ, the tunica alhuginea^
which is extremely dense and firm in struc-
ture, and incloses a peculiar soft fibrous tissue,
or stroma, abundantly suitiilicd with blood-
vessels (Fig. 504). Iml)cddc<l in the meshes
of this tissue are numerous small, round,
transparent vesicles, in various stages of de-
velopment ; they are the Graafian vesicles^
the ovisacs containing the ova. Tn women who have not borne children, they
vary in numbcj- from ten to fifteen or twenty; and in size from a pin's head
Fig. 505. — Section of the Graafian
Vesicle. After Von Baor.
reriti
APPENDAGES OF THE UTERUS. 87o
to a pea; but Dr. Martin Barry has sliown, that a large number of microscopic
ovisacs exist in tlie parenchyma of the organ, few of which produce ova. These
vesicles have thin, transparent walls, and are filled with a clear, colorless, albu-
minous fluid.
The Oraafian vesicles are, during their early development, small, and deeply
seated in the substance of the ovary; as they enlarge, they approach tlie surface;
and, when mature, form small projections on the exterior of the ovary beneath
the peritoneum. Each vesicle consists of an external fibro-vascular coat con-
nected with the surroanding stroma of the ovary by a network of bloodvessels ;
and an internal coat, named ovicapsule, which is lined by a layer of nucleated
cells, called the membrana granulosa. The fluid contained in the interior of the
vesicles is transparent and albuminous, and in it is suspended the ovum.
The formation, development, and maturation of the Graafian vesicles and ova
continue uninteruptedly from infancy to the end of the fruitful period of woman's
life. Before puberty, the ovaries are small, the Graafian vesicles contained in
them minute, and few in number ; and few, probably, ever attain full develop-
ment, but shrink and disappear, their ova being incapable of impregnation. At
puberty the ovaries enlarge, are more vascular, the Graafian vesicles are de-
veloped in greater abundance, and their ova are capable of fecundation.
Discharge of the Ovmn. The Graafian vesicles, after gradually approaching
the surface of the ovary, burst ; the ovum and fluid contents of the vesicles are
liberated, and escape on the exterior of the ovary, passing from thence into the
Fallopian tube, the fimbriated processes of which are supposed to grasp the
ovary, the aperture of the tube being applied to the part corresponding to the
matured and bursting vesicle. In the human subject and most mammalia, the
maturation and discharge of the ova occur at regular periods only, and are indi-
cated, in the mammalia, by the phenomena of heat or rut ; and in the human
female, by menstruation. Sexual desire is more intense in females at this period ;
and if the union of the sexes takes place, the ovum may be fecundated.
Corpus Luteum. Immediately after the rupture of a Graafian vesicle, and
the escape of its ovum, the vesicle is filled with blood-tinged fluid; and in a
short time the circumference of the vesicle is occupied by a firm, yellow sub-
stance, which is probably formed from plasma exuded from its walls. Dr. Lee
believes that this yellow matter is deposited outside both the membranes of the
follicle; Montgomery regards it as placed between the layers; while Kolliker
considers it as a thickening of the inner layer of the outer coat of the follicle.
The exudation is at first of a dark brown or brownish-red color, but it soon
becomes paler, and its consistence more dense.
For every follicle in the ovary from which an ovum is discharged, a corpus
luteum will be found. But the characters it exhibits, and the changes produced
in it will be determined by the circumstance of the ovum being impregnated or not.
Although there is little doubt that corpora lutea exist in the ovaries after the
escape of ova, independent of coitus or impregnation, it appears that the corpus
luteum of pregnancy (true corpus luteum) possesses characters by which it may
be distinguished from one formed in a follicle, from which an ovum has been
discharged without subsequent impregnation (false corpus luteum).
The true corpora lutea are of large size, often as large as a mulberry; of a
rounded form, and project from the surface of the ovary, the summit of the pro-
jection presenting a triangular depression or cicatrix, where the peritoneum
appears to have been torn. They contain a small cavity in their centre during
the early period of their formation, which becomes contracted, and exhibits a
stellate cicatrix during the latter stages of pregnancy. Their vascularity, lobu-
lated or puckered appearance, firm consistence, and yellow color, are also char-
acteristic marks of true corpora lutea.
False corpora lutea are of small size, do not project from the surface of the
ovary, are angular in form, seldom present any cicatrix, contain no cavity in
their centre: the material composing them is not lobulated, its consistence is
876 FEMALE ORGANS OF GENERATION.
usually soft, often resembling, coagulated blood; the yellow matter exists in the
form of a very thin layer, or more commonly is entirely wanting. False corpora
lutea most frequently result from the effusion into the cavities of the GraaiSan
vesicles of serum or blood, which subsequently undergoes various changes, and
is ultimately removed. Dr. Lee states, that in the false corpora lutea the yellow
substance is contained within, or attached to, the inner surface of the Graafian
vesicle, and does not surround it, as is the case in the true corpora lutea.
In the foetus, the ovaries are situated, like the testes, in the lumbar region
near the kidneys. They may be distinguished from those bodies at an early
period by their elongated and flattened form, and by their position, which is at
first oblique, and then nearly transverse. They gradually descend into the
pelvis.
Lying above the ovary in the broad ligament between it and the Fallopian
tube is the organ of BosenmuUer, called also the parovariuin or epoophoron.
This is the remnant of a foetal structure, the development of which has been
described in the Introduction. In the adult it consists of a few closed convo-
luted tubes lined with epithelium, some of them atrophied, and one usually
distinguishable from the rest by ending in a bulbous or hydatid swelling. The
parovarium is connected at its uterine extremity with the remains of the Wolffian
duct, the duct of Gaertner.
The Ligament of the ovary is a rounded cord, which extends from each supe-
rior angle of the uterus to the inner extremity of the ovary ; it consists of fibrous
tissue and a few muscular fibres derived from the uterus.
The Round Ligaments are two rounded cords, between four and five inches
in length, situated between the layers of the broad ligament in front of and
below the Fallopian tube. Commencing on each side at the superior angle of
the uterus, this ligament passes forwards and outwards through the internal
abdominal ring, along the inguinal canal to the labia majora, in which it becomes
lost. The round ligament consists of areolar tissue, vessels and nerves, besides
a dense bundle of fibrous tissue, and muscular fibres prolonged from the uterus,
inclosed in a duplicature of peritoneum, which, in the foetus, is prolonged in the
form of a tubular process for a short distance into the inguinal canal. This
process is called the canal of Nuch. It is generally obliterated in the. adult, but
sometimes remains pervious even in advanced life. It is analogous to the peri-
toneal pouch which accompanies the descent of the testis.
Vessels and Nerves. The arteries of the ovaries and Fallopian tubes are the
ovarian from the aorta. They anastomose with the termination of the uterine
arteries, and enter the attached border of the ovary. The veins follow the course
of the arteries; they form a plexus near the ovary, the pampiniform plexus.
The nerves are derived from the inferior hypogastric, or pelvic, plexus and from
the ovarian plexus, the Fallopian tube receiving a branch from one of the uterine
nerves.
Mammary Glands.
The Mammfie, or breasts, are accessory glands of the generative system, which
secrete the milk. They exist in the male as well as in the female ; but in the
former only in a rudimentary state, unless their growth is excited by peculiar
circumstances. In the fen^ale, they are two large hemispherical eminences sit-
uated towards the lateral aspect of the pectoral region corresponding to the in-
terval between the third and sixth or seventh ribs, and extending from the side
of the sternum to tlu^ nxilhi. Their weight and dimensions differ at different
periods of life, and in (lin'erent individuals. Before puberty they are of small si;^e,
but enlarge as the generative organs become more completely developed. They
increase during pregnancy, and especially after delivery, and become atrophied
in old age. The left mamma is generally a little larger than the right. Their
base is nearly circular, flattened or slightly concave, and has its long diameter
MAMMARY GLAND. 877
directed upwards and outwards towards the axilla : they are separated from the
Pectoral muscles by a thin layer of superficial fascia. The outer surface of the
mamma is convex, and presents, just below the centre, a small conical promi-
nence, the nipple {rnammilla). The surface of the nipple is dark-colored, and
surrounded by an areola having a colored tint. In the virgin, the areola is of
a delicate rosy hue ; about the second month of impregnation, it enlarges, and
acquires a darker tinge, which increases as pregnancy advances, becoming, in
some cases, of a dark brown, or even black color. This color diminishes as soon
as lactation is over, but is never entirely lost through life. These changes in
the color of the areola are of extreme importance in forming a conclusion in
a case of suspected pregnancy.
The nipple is a cylindrical or conical eminence, capable of undergoing a sort
of erection from mechanical excitement. It is of a pink or brownish hue, its
surface wrinkled and provided with papillae, and it is perforated by numerous
orifices, the apertures of the lactiferous ducts. Near the base of the nipple, and
upon the surface of the areola, are numerous sebaceous glands, which become
much enlarged during lactation, and present the appearance of small tubercles
beneath the skin. These glands secrete a peculiar fatty substance, which serves
as a protection to the integument of the nipple in the act of sucking. The
nipple consists of numerous vessels, which form a kind of erectile tissue, inter-
mixed with plain muscular fibres.
Structure. The mamma consists of gland-tissue; of fibrous tissue, connecting
its lobes ; and of fatty tissue in the intervals between the lobes. The mammary
gland, when freed from cellular tissue and fat, is of a pale reddish color, firm in
texture, circular in form, flattened from before backwards, thicker in the centre
than at the circumference, and presenting several inequalities on its surface,
especially in front. It consists of numerous lobes, and these are composed of
lobules, connected together by areolar tissue, bloodvessels, and ducts. The
smallest lobules consist of a cluster of rounded vesicles, which open into the
smallest branches of the lactiferous ducts ; these ducts uniting, form larger ducts,
which terminate in a single canal, corresponding with one of the chief sub-
divisions of the gland. The number of excretory ducts varies from fifteen to
twenty: they are termed the tuhuli lactiferi, t. galactophori. They converge to-
wards the areola, beneath which they form dilatations, or ampullae, which serve
as reservoirs for the milk, and, at the base of the nipple, become contracted,
and pursue a straight course to its summit, perforating it by separate orifices
considerably narrower than the ducts themselves. The ducts are composed of
areolar tissue, with longitudinal and transverse elastic fibres, and longitudinal
muscular fibres: their mucous lining is continuous, at the point of the nipple,
with the integument : the epithelium is of the tessellated or scaly variety near
the orifices of the ducts, and columnar in the deeper parts of the gland.
The fibrous tissue invests the entire surface of the breast, and sends down septa
between its lobes, connecting them together.
1^\\Q fatty tissue surrounds the surface of the gland, and occupies the intervals
between its lobes and lobules. It usually exists in considerably abundance, and
determines the form and size of the gland. There is no fat immediately beneath
the areola and nipple.
Vessels and Nerves. The arteries supplying the mammee are derived from
the thoracic branches of the axillary, the mtercostals, and internal mammary.
The veins describe an anastomotic circle round the base of the nipple, called by
Haller the circulus venosus. From this, large branches transmit the blood to
the circumference of the gland, and end in the axillary and internal mammary
veins. _ The lymphatics run along the lower border of the Pectoralis major to
the axillary glands. The nerves are derived from the anterior and lateral cuta-
neous nerves of the thorax.
The Surgical Anatomy of Inguinal Hernia.
Dissection (Fig. 506). For dissection of the parts concerned in inguinal hernia, a male subject,
free from fat, should always be selected. The body should be placed in the supine position', the
abdomen and pelvis raised by means of blocks placed beneath them, and the lower extremities
rotated outwards, so as to make the parts as tense as possible. If the abdominal walls are
flaccid, the cavity of the abdomen should be inflated by an aperture through the umbilicus. An
incision should be made along the middle line, from the umbilicus to the pubes, and continued
along the front of the scrotum ; and a second incision, from the anterior superior spine of the
ilium to just below the umbilicus. These incisions should divide the integument; and the tri-
angular-shaped flap included between them should be reflected downwards and outwards, when
the superficial fascia will be exposed.
The superficial fascia in tliis region consists of two layers, between whicli are
found the superficial vessels and nerves, and the inguinal lymphatic glands.
The superficial layer is thick, areolar in texture, containing adipose tissue in
its meshes, the quantity of which varies in different subjects. Below, it passes
over Poupart's ligament, and is continuous with the outer layer of the superficial
fascia of the thigh. This fascia is continued as a tubular prolongation around
the outer surface of the cord and testis. In this situation, it changes its charac-
ter ; it becomes thin, destitute of adipose tissue, and of a pale reddish color, and
assists in forming the dartos. From the scrotum, it may be traced backwards
to be continuous with the superficial fascia of the perineum. This layer should
be removed, by dividing it across in the same direction as the external incisions,
and reflecting it downwards and outwards, when the following vessels and
nerves will be exposed : —
The superficial epigastric, superficial circumflex iliac, and superficial external
pudic vessels ; the terminal filaments of the ilio-hypogastric and ilio-inguinal
nerves ; and the upper chain of inguinal lymphatic glands.
The superficial epi(jastric artery crosses Poupart's ligament, and ascends ob-
liquely towards the umbilicus, lying midway between the spine of the ilium and
the pubes. It supplies the integument, and anastomoses with the deep epigas-
tric. This vessel is a branch of the common femoral artery, and pierces the
fascia lata, below Poupart's ligament. Its accompanying vein empties itself
into the internal saphenous, after having pierced the cribriform fascia.
The suj)erficial circumflex iliac artery passes outwards towards the crest of the
ilium.
The superficial external pudic artery passes transversely inwards across the
spermatic cord, and supplies the integument of the hypogastric region, and of
the penis and scrotum. This vessel is usually divided in the first incision made
in the operation for inguinal hernia, and occasionally requires the application of
a ligature.
The veins accompanying these superficial vessels are usually much larger^
than the arteries : they terminate in the internal saphenous vein.
Lympjhatic vessels ^XQ found, taking the same course as the bloodvessels; they
return the lymph from the superficial structures in the lower part of the abdo-
men, the scrotum, penis, .'ind external surface of the bnttock, and terminate in a
srn.'ill (;hain of ]ym])hatic glands, three or four in number, which lie on a level
with Poupart's ligament.
Nerves. The terminal brunch of the ili()-ing\tinal nerve emerges at the exter-
nal abdominal ring: and the hypogastric branch of the ilio-hypogastric nerve
perforates the ayioncurosis of the external oblique, above and to the outer side
of the external ring.
(878)
EXTERNAL OBLIQUE MUSCLE.
879
The deeiD layer of superficial fascia should be divided across in the same
direction as the external incisions, separated from the aponeurosis of the Ex-
ternal oblique, to which it is connected by delicate areolar tissue, and reflected
downwards and outwards. It is thin, aponeurotic in structure, and of considera-
ble strength. It is intimately adherent, in the middle line, to the linea
alba, and below, to the whole length of Poupart's ligament and the upper part
of the fascia lata. It forms a thin tubular prolongation round the outer surface
of the cord, which blends with the superficial layer, and is continuous with the
dartos of the scrotum. From the back of the scrotum, the conjoined layers
may be traced into the perineum, where they are continuous with the deep layer
of the superficial fascia in that region, which is attached, behind, to the triangular
ligament, and on each side, to the ramus of the pubes and ischium. The con-
nections of this fascia serve to explain the course taken by the urine in extra-
vasation of that fluid from rupture of the urethra : passing forwards from the
perineum into the scrotum, it ascends on to the abdomen, but is prevented
extending into the thighs by the attachment of the fascia to the ramus of the
pubes and ischium, on each side, and to Poupart's ligament in front, and is
prevented from passing on to the buttock by the posterior connections of the
perineal fascia.
Fig, 506. — Inguinal Hernia. Superficial Dissection.
Hii V.
Ejcterriai
Aiiiomtnal Ring
The aponeurosis of the External ohlique muscle is exposed on the removal of
this fascia. It is a thin, strong, membranous aponeurosis, the fibres of which
are directed obliquely downwards and inwards. It is attached to the anterior
superior spinous process of the ilium, the spine of the pubes, the linea ilio-pec-
880 SURGICAL ANATOMY OF INGUINAL HERNIA.
tinea, front of tlie pubes and linea alba. That portion of the aponeurosis which
extends from the anterior sujDerior spine of the ilium, to the spine of the pubes,
is termed Poupart's Ligament, or the crural arch ; and that portion which is
inserted into the pectineal line, is termed Gimbernat's Ligament.
Just above and to the outer side of the crest of the pubes, an interval is
seen in the aponeurosis of the External oblique, called the external abdominal
ring^ which transmits the spermatic cord in the male, and the round ligament in
the female. This aperture is oblique in direction, somewhat triangular in form,
and corresponds with the course of the fibres of the aponeurosis. It usually
measures from base to apex about an inch, and transversely about half an inch.
It is bounded below by the crest of the os pubis ; above, by a series of curved
fibres, the intercoluinnar^ which pass across the upper angle of the ring so as to
increase its strength ; and on either side, by the free borders of the aponeurosis,
which are called the columns or pillars of the ring.
The external jpillar^ which, at the same time, is inferior from the obliquity of
its direction, is the stronger ; it is formed by that portion of Poupart's ligament
which is inserted into the spine of the pubes ; it is curved round the spermatic
cord, so as to form a kind of groove, upon which the cord rests.
The internal or superior pillar is a broad, thin, flat band, which interlaces
with its fellow on the opposite side, in front of the symphysis pubis, that of the
right side being superficial.
The external abdominal ring gives passage to the spermatic cord in the male,
and round ligament in the female ; it is much larger in men than in women, on
account of the large size of the spermatic cord, and hence the greater frequency
of inguinal hernia in men.
The intercolumnar fibres are a series of curved tendinous fibres, which arch
across the lower part of the aponeurosis of the External oblique. They havQ
received their name from stretching across between the two pillars of the exter-
nal ring ; they increase the strength of the membrane which bounds the upper
part of this aperture, and prevent the divergence of the pillars from one another.
They are thickest below, where they are connected to the outer third of Pou-
part's ligament, and are inserted into the linea alba ; describing a curve, with
the convexity downwards. They are much thicker and stronger at the outer
angle of the external ring than internally, and are more strongly developed in
the male than in the female. These fibres are continuous with a thin fascia,
which is closely connected to the margins of the external ring, and has received
the name of the intercolumnar or external spermatic fascia ; it forms a tubular
prolongation around the outer surface of the cord and testis, and incloses them
in a distinct sheath. The sac of an inguinal hernia, in passing through the ex-
ternal abdominal ring, receives an investment from the intercolumnar fascia.
The finger should be introduced a short distance into the external ring, and
then, if the limb is extended and rotated outwards, the aponeurosis of the Ex-
ternal oblique, together with the iliac portion of the fascia lata, will be felt to
become tense, and the external ring much contracted ; if the limb is, on the
contrary, flexed upon the pelvis and rotated inwards, this aponeurosis will
become lax, and the external ring sufficiently enlarged to admit the finger with
comparative case: hence the patient should always be put in the latter ])osition
when the taxis is applied for the reduction of an inguinal hernia, in order that
the abdominal walls may be as much relaxed as possible.
The aponoiirosis of tliR Kxtornal oblique phoul<l be removed by dividinij it across in 1lic pame
{lircclion uh llio external incisions, and reflecting it outwards; great care is requisite in separating
it from tlie apon(!urosis of the muscle l)eiieath. The lower part of the Internal 0))lique and the
(-'remaster are tlien exposed, together with the inguinal canal, which contains the spermatic cord
(Fig. 507). The mode of insertion of Poupart's and Gimbernat's ligaments into the pubes should
also be examined.
PouparCs ligament, or tho crural arrh^ extends from, the anterior superior
spine of the ilium to the spine of the pubes. It is also attached to the pectineal
GIMBERNAT'S LIGAMENT.
881
line to the extent of about an inch, forming Gimbernat's hgament. Its general
direction is curved towards the thigh, where it is continuous with the fascia
lata. Its outer half is rounded, oblique in its direction, and continuous with the
iliac fascia. Its inner half gradually widens at its attachment to the pubes, is
more horizontal in direction, and lies beneath the spermatic cord.
Qimhernath ligament i^ that portion of the aponeurosis of the External oblique
which is inserted into the pectineal line ; it is thin, membranous in structure,
triangular in shape, the base directed outwards, and passes upwards and back-
wards beneath the spermatic cord, from the spine of the os pubis to the pecti-
neal line, to the extent of about half an inch.
The triangular ligament is a band of tendinous fibres, of a triangular shape,
which is continued from Poupart's ligament at its attachment to the pectineal
line upwards and inwards, behind the inner pillar of the external ring to the
linea alba.
The Internal Oblique Muscle has been described (p. 385). The part which is
now exposed is partly muscular and partly tendinous in structure. Those
fibres which arise from the outer part of Poupart's ligament are thin, pale in
color, curve downwards, and terminate in an aponeurosis, which passes in front
of the Rectus and Pyramidalis muscles, to be inserted into the crest of the os
Fig. 507. — Inguinal Hernia, showing the Internal Oblique,
Cremaster, and Spermatic Canal.
4\"^
pubis and pectineal line, to the extent of half an inch, in common with that of
the Transversalis muscle, forming by their junction the conjoined tendon. This
tendon is placed immediately behind Gimbernat's ligament and the external
abdominal ring, and serves to strengthen what would otherwise be a very weak
point in the abdominal wall. When a direct inguinal hernia passes through the
external ring, the conjoined tendon usually forms one of its coverings.
The Cremaster is a slender muscular fasciculus, which arises from the middle
of Poupart's ligament at the inner side of the Internal oblique, being connected
56
882 SURGICAL ANATOMY OF INGUINAL HERNIA.
with that muscle, and also occasionally with the Transversalis. It passes along
the outer side of the spermatic cord, descends with it through the external ring
upon the front and sides of the cord, and forms a series of loops, which difter in
thickness and length in different subjects. Those at the upper part of the cord
are exceedingly short, but they become in succession longer and longer, the
longest reaching down as low as the testicle, where a few are inserted into the
tunica vaginalis. These loops are united togethe-r by areolar tissue, and form
a thin covering over the cord, the fascia cremasterica. The fibres ascend along
the inner side of the cord, and are inserted by a small pointed tendon, into the
crest of the os pubis and front of the sheath of the Eectus muscle.
It will be observed, that the origin and insertion of the Cremaster is precisely
similar to that of the lower fibres of the Internal oblique. This fact affords an
easy exi^lanation of the manner in which the testicle and cord are invested by
this muscle. At an earlj^ period of foetal life, the testis is placed at the lower
and back part of the abdominal cavity, but, during its descent towards the scro-
tum, which takes place before birth, it passes beneath the arched border of the
Internal oblique. In its passage beneath this muscle some fibres are derived
from its lower part, which accompany the testicle and cord into the scrotum.
It occasionally happens that the loops of the Cremaster surround the cord,
some lying behind as well as in front. It is probable that, under these circum-
stances, the testis, in its descent, passed through instead of beneath the fibres of
the Internal oblique.
In the descent of an oblique inguinal hernia, which takes the same course as
the spermatic cord, the Cremaster muscle forms one of its coverings. This
muscle becomes largely developed in cases of hydrocele and large old scrotal
hernige. No such muscle exists in the female, but an analogous structure is
developed in those cases where an oblique inguinal hernia descends beneath the
margin of the Internal oblique.
The Internal Oblique should be detached from Poupart's ligament, separated from the Trans-
versalis to the same extent as in the previous incisions, and reflected inwards on to the sheath of
the Rectus (Fig. 508). The circumflex iliac vessels, which lie between these two muscles, form
a valuable guide to their separation.
The Transversalis muscle has been previously described (p. 388). Its lower
part is partly fleshy and partly tendinous in structure ; this portion arises from
the outer third of Poupart's ligament, and, arching downwards and inwards
over the cord, terminates in an aponeurosis, which is inserted into the linea alba,
the crest of the pubes, and the pectineal line to the extent of an inch, forming,
together with the Internal oblique, the conjoined tendon. Between the lower
border of this muscle and Poupart's ligament, a space is left in which is seen
the fascia transversalis.
The iwjuinal^ or spermatic canal, contains the spermatic cord in the male, and
the round ligament in the female. It is an oblique canal, about an inch and a
half in length, directed downwards and inwards, and placed parallel with, and
a little above, Poupart's ligament. It communicates, above, with the cavity of
the abdomen, by means of the internal abdominal ring, which is the point
where the cord enters the spermatic canal; and terminates, below, at the exter-
nal ring. It is bounded, in front, by the integument and superficial fascia, by
the aponeurosis of the External oblique throughout its whole length, and by the
Internal oblique for its outer third ; behind, by the conjoined tendon of the
Internal oblique and Transversalis, the triangular ligament, transversalis fascia,
and the subperitoneal fat and peritoneum ; above, b}" the arched fibres of the
Internal ol)lif|uc and Transvcrsahs ; below, by the union of the fiiscia trans-
versalis with Poii])art's ligament. That form of protrusion in which the intes-
tine follows the course of the spermatic cord along the spermatic canal, is called
ohlique inrjuinal hernia.
^\\c fascia transversalis \^ a ihm aponeurotic membrane, which lies between
the inner surface of the transversalis muscle and the peritoneum. It forms part
FASCIA TRANSVERSALIS.
883
of tlie general layer of fascia wliicli lines the interior of tlie abdominal and pelvic
cavities, and is directly continuous with the iliac and pelvic fasciae.
In the inguinal region, the transversalis fascia is thick and dense in structure
and joined by fibres from the aponeurosis of the Transversalis; but it becomes
thin and cellular as it ascends to the Diaphragm. Below, it has the following
attachments: external to the femoral vessels, it is connected to the posterior
margin of Poupart's ligament, and is there continuous with the iliac fascia. In-
ternal to the vessels it is thin, and attached to the pubes and pectineal line,
behind the conjoined tendon, with which it is united ; and, corresponding to the
points where the femoral vessels pass into the thigh, this fascia descends in front
of them, forming the anterior wall of the crural sheath.
Fiff. 508.-
-Inguinal Hernia, showing the Transvei'salis Muscle, the Transversalis Fascia,
and the Internal Abdominal Rinor.
The internal abdominal ring is situated in the transversalis fascia, midway
between the anterior superior spine of the ilium and the spine of the pubes, and
about half an inch above Poupart's ligament. It is of an oval form, the extremi-
ties^ of the oval directed upwards and downwards, varies in size in different
subjects, and is much larger in the male than in the female. It is bounded,
above, by the arched fibres of the Transversalis muscle, and internally, by the
epigastric vessels. It transmits the spermatic cord in the male, and the round
ligament in the female, and from its circumference a thin, funnel-shaped mem-
brane, the infundibuliform fascia, is continued round the cord and testis inclosing
them in a distinct pouch. When the sac of an oblique inguinal hernia passes
through the internal ring, the infundibuliform process of the transversalis fascia
forms one of its coverings.
Between the fascia transversalis and the peritoneum is a quantity of loose
areolar tissue. In some subjects it is of considerable thickness, and loaded
with adipose tissue. Opposite the internal ring, it is continued round the surface
of the cord, forming a loose sheath for it.
The epigastric artery bears a very important relation to the internal abdomi-
884 SURGICAL ANATOMY OF INGUINAL HERNIA.
nal ring. This vessel lies between tlie transversalis fascia and peritoneum, and
passes obliquely upwards andin^!va■rds, from its origin from the external iliac, to
the margin of the sheath of the rectus muscle. In this course it lies along the
lower and inner margin of the internal ring, and beneath the commencement
of the spermatic cord, the vas deferens curving round it as it passes from the
ring into the pelvis.
The peritoneum, corresponding to the inner surface of the internal ring, pre-
sents a well-marked depression, the depth of which varies in diiierent subjects.
A thin fibrous band is continued from it along the front of the cord, for a vari-
able distance, and becomes ultimately lost. This is the remains of the pouch
of peritoneum which, in the foetus, accompanies the cord and testis into the
scrotum ; the obliteration of which commences soon after birth. In some cases
the fibrous band can only be traced a short distance ; but occasionally it may be
followed, as a fine cord, as far as the upper end of the tunica vaginalis. Some-
times the tube of peritoneum is only closed at intervals, and presents a saccu-
lated appearance; or a single pouch may extend along the whole length of the
cord, which may be closed above ; or the pouch may be directly continuous with
the peritoneum by an opening at its upper part.
Inguin'al Hernia.
Inguinal Hernia is that form of protrusion which makes its way through the
abdomen in the inguinal region.
There are two principal varieties of inguinal hernia : external or oblique, and
internal or direct.
External or ohlique inguinal hernia, the more frequent of the two, takes the
same course as the spermatic cord. It is called external from the neck of the
sac being on the outer or iliac side of the epigastric artery.
Internal^ or direct inguinal hernia does not follow the same course as the
cord, but protrudes through the abdominal wall on the inner or pubic side of
the epigastric artery.
Oblique Inguinal Hernia.
In Oblique Inguinal Hernia, the intestine escapes from the abdominal cavity
at the internal ring, pushing before it a pouch of peritoneum, which forms the
hernial sac. As it enters the inguinal canal, it receives an investment from the
subserous areolar tissue, and is inclosed in the infundibuliform process of the
transversalis fascia. In passing along the inguinal canal, it displaces upwards
the arched fibres of the Transversalis and Internal oblique muscles, and is sur-
rounded by the fibres of the Cremaster. It then passes along the front of the
cord, and escapes from the inguinal canal at the external ring, receiving an
investment from the intercolumnar fascia. Lastly, it descends into the scrotum,
receiving coverings from the superficial fascia and the integument.
The coverings of this form of hernia, after it has passed through the external
ring, arc, from without inwards, the integument, superficial fascia, intercolumnar
fascia, Cremaster muscle, infundibuliform fascia, subserous cellular tissue, and
peritoneum.
This form of hernia lies in front of the vessels of the spermatic cord, and
seldom extends below the testis, on account of the intimate adhesion of the
coverings of the cord to the tunica vaginalis.
The seat of stricture in oblique inguinal hernia, is cither at the external ring
in tlie inguinal canal, caused by the fibres of the Internal oblique or Transver-
salis, or at the internal ring, more frequently in the latter situation. If it is situ-
ated at the external ring, tlic division of a few fibres at one point of its circum-
ference is all that is necessary for the replacement of tlie hernia. If in the ingui-
nal canal, or at the internal ring, it will be necessary to divide the aponeurosis
DIRECT INGUINAL HERNIA. 885
of tlie External oblique so as to lay open tlie inguinal canal. In dividing the
stricture, the direction of the incision should be directly upwards.
When the intestine passes along the spermatic canal, and escapes from the
external ring into the scrotum, it is called complete oblique inguinal or scrotal
hernia. If the intestine does not escape from the external ring, but is retained
in the inguinal canal, it is called incomplete inguinal hernia or huhonocele. In
each of these cases, the coverings which invest it will depend upon the extent
to which it descends in the inguinal canal.
There are two other varieties of oblique inguinal hernia : the congenital and
infantile.
Congenital hernia is liable to occur in those cases where the pouch of perito-
neum which accompanies the cord and testis in its descent in the foetus remains
unclosed, and communicates directly with the peritoneum. The intestine de-
scends along this pouch into the cavity of the tunica vaginalis, and lies in con-
tact with the testis. This form of hernia has no proper sac, being contained
within the tunica vaginalis.
In Infantile hernia^ the hernial sac descends along the inguinal canal into the
scrotum, behind the pouch of peritoneum which accompanies the cord and testis
into the same part. The abdominal aperture of this pouch is closed, but the
portion contained in the inguinal canal remains unobliterated. The hernial sac
is consequently invested, more or less completely, by the posterior layer of the
tunica vaginalis, from which it is separated by a little loose areolar tissue ; so
that in operating upon this variety of hernia, three layers of peritoneum would
require division ; the first and second being the layers of the tunica vaginalis,
the third the anterior layer of the hernial sac.
Direct Inguinal Hernia.
In Direct Inguinal Hernia, the protrusion makes its way through some part
of the abdominal wall internal to the epigastric artery, and passes directly through
the abdominal parietes and external ring. At the lower part of the abdominal
wall IS a triangular space (Hesselbach's triangle), bounded, externally, by the
epigastric artery ; internally, by the margin of the Eectus muscle : below, by
Poupart's ligament. The conjoined tendon is stretched across the inner two-
thirds of this space, the remaining portion of the space being filled in by the
transversalis fiascia.
In some cases the hernial protrusion escapes from the abdomen on the outer
side of the conjoined tendon, pushing before it the peritoneum, the subserous
cellular tissue, and the transversalis fascia. It then enters the inguinal canal,
passing along nearly its whole length, and finally emerges from the external
ring, receiving an investment from the intercolumnar fascia. The coverings of
this form of hernia are precisely similar to those investing the oblique form.^
In other cases, and this is the more frequent variety, the intestine is either
' The difference between the position of the neck of the sac in these two forms of direct ingui-
nal hernia has been referred, with some probability, to a difference in the relative positions of the
obliterated hypogastric artery and the epigastric artery. The projection of the hypogastric
artery towards the cavity of the abdomen produces two fosses in the peritoneum. When the
course of the obliterated hypogastric artery corresponds pretty nearly with that of the epigastric,
which is regarded as the normal arrangement, the bottom of the external fossa of the peritoneum
corresponds to the position of the internal abdominal ring ; and a hernia which distends and
pushes out the peritoneum lining this fossa is an oblique hernia. When, on the other hand, the
obliterated hypogastric artery lies considerably to the inner side of the epigastric it divides the
triangle of Hesselbach into two parts. In that case a hernia may distend and push out the peri-
toneum forming the bottom of the external fossa, and by so doing will protrude the tissues which
form the abdominal wall between the internal ring and the conjoined tendon. It will be a direct
hernia, since the neck of the sac lies internal to the epigastric artery : but its coverings, as stated
in the text, will be identical with those of the oblique form, with the insignificant difference that
the covering from the transversalis fascia is taken from another source, and not from its infundi-
buliform process.
886 SURGICAL ANATOMY OF INGUINAL HERNIA.
forced tlirougli tlie fibres of the conjoined tendon, or the tendon is gradually
distended in front of it, so as to form a complete investment for it. The intestine
then enters the lower end of the inguinal canal, escapes at the external ring
lying on the inner side of the cord, and receives additional coverings from the
superficial fascia and the integument. This form of hernia has the same cover-
ings as the oblique variety, excepting that the conjoined tendon is substituted
for the Cremaster, and the infundibulum fascia is replaced by a part of the
general fascia transversalis.
The seat of stricture in both varieties of direct hernia is most frequently at the
neck of the sac, or at the external ring. In that form of hernia which perfo-
rates the conjoined tendon, it not unfrequently occurs at the edges of the i:ssure
through which the gut passes. In dividing the stricture, the incision should in
all cases be directed upwards.
If the hernial protrusion passes into the inguinal canal, but does not escape
from the external abdominal ring, it forms what is called incomijlete direct hernia.
This form of hernia is usually of small size, and in corpulent persons very
difficult of detection.
Direct inguinal hernia is of much less frequent occurrence than the oblique.
Their comparative frequency being, according to Cloquet, as one to five. It
occurs far more frequently in men than in women, on account of the larger size
of the external ring in the former sex. It differs from the oblique in its smaller
size and globular form, dependent most probably on the resistance offered to its
progress by the transversalis fascia and conjoined tendon. It differs also in its
position, being placed over the pubes, and not in the course of the inguinal canal.
The epigastric artery runs on the outer or iliac side of the neck of the sac, and
the spermatic cord along its external and posterior side, not directly behind it,
as in oblique inguinal hernia.
SUEGICAL ANATOMY OF FEMOEAL HEENIA.
The dissection of the parts comprised in the anatomy of femoral hernia should be performed,
if possible, upon a female subject free fi-oni fat. 'J'lie subject should lie upon its back ; a block
is first placed under the pelvis, the thigh everted, and the knee slightly bent, and retained in this
position. An incision should then be made from the anterior superior spinous process of the ilium
along Poupart's ligament to the symphysis pubis ; a second incision should be carried transversely
across the thigh about six inches beneath the preceding; and these are to be connected together
by a vertical one carried along the inner side of the thigh. These several incisions should divide
merely the integument; this is to be reflected outwards, when the superficial fascia will be exposed.
The su'perficial fascia, at the upper part of the thigh, consists of two layers,
between which are found the cutaneous vessels and nerves, and numerous lym-
phatic glands.
The superficial layer is a thick and dense cellulo-fibrous membrane in the
meshes of which is found a considerable amount of adipose tissue, varying in
quantity in different subjects : this layer may be traced upwards over Poupart's
ligament to be continuous with the superficial fascia of the abdomen ; whilst
below, and on the inner and outer sides of the limb, it is continuous with the
superficial fascia covering the rest of the thigh.
This layer should be detached by dividing it across in the same direction as the external in-
cisions ; its removal will l)c facilitated by commencing at the lower and inner angle of the space,
detaching it at first from the front of the internal saphenous vein, and dissecting it off from the
anterior surface of that vessel and its branches; it should then be reflected outwards, in the same
manner as the integument. 'I'he cutaneous vessels nnd nerves, and superficial inguinal glands, are
then exposed, lying upon tlie deep layer of the superficial fascia, 'llicse are the internal saphe-
nous v(dn, and th(! superficial epigastric, superficial circuniflexa ilii, and superficial external pudic
vessels, as well as numerous lymphatics ascending with the saphenous vein to the inguinal glands.
The internal saplienons vein is a vessel of considerable size which ascends
obliquely upwards along the inner side of the thigh, below Poupart's ligament.
FEMORAL HERNIA.
887
It passes tlirougli tke saphenous opening in the fascia lata to terminate in the
femoral vein. This vessel is accompanied by numerous lymphatics, which
return the lymph from the dorsum of the foot and inner side of the leg and
thigh : they terminate in the inguinal glands, which surround the saphenous
opening. Diverging from the same point are the superficial epigastric vessels,
which run across Poupart's ligament, obliquely upwards and inwards, to the
lower part of the abdomen : the superficial circumflexa ilii vessels, which pass
Fig. 509. — Femoral Hernia. Superficial Dissection,
obliquely outwards along Pouj^art's ligament to the crest of the ilium : and the
superficial external pudic vessels, which pass inwards to the perineum and
scrotum. These vessels supply the subcutaneous areolar tissue and the integu-
ment, and are accompanied by numerous lymphatic vessels, which return the
lymph from the same parts to the inguinal glands.
The superficial inguinal glands are arranged in two groups, one of which is
disposed above and parallel with Poupart's ligament, and the other below the
ligament, surrounding the termination of the saphenous vein, and following
(occasionally) the course of that vessel a short distance along the thigh. The
upper chain receives the lymphatic vessels from the penis, scrotum, lower part
of the abdomen, perineum, and buttock ; the lower chain receives the lymphatic
vessels from the lower extremity.
The nerves supplying the integument of the region are derived from the ilio-
inguinal, the genito-crural, and anterior crural. The ilio-inguinal nerve may
be found on the inner side of the internal saphenous vein, the terminal branch
SURGICAL ANATOMY OF INGUINAL HERNIA.
of the genito-crural nerve outside tlie vein, and the middle and external cuta-
neous nerves more external.
The deep layer of superficial fascia should be divided in the same direction
as the external incisions, and separated from the fascia lata: this is easily
effected from its extreme thinness. It is a thin but dense membrane, placed
beneath the subcutaneous vessels and nerves, and upon the surface of the fascia
lata. It is intimately adherent above to the lower margin of Poupart's ligament,
and about one inch below this ligament covers the saphenous opening in the
Fig. 510. — Femoral Hernia, showing Fascia Lata and Saphenous Opening.
fascia lata, is closely united to its circumference, and is connected to the sheath
of the femoral vessels corresponding to its under surface. The portion of fascia
covering this aperture is perforated by the internal saphenous vein, and by
numerous blood and lymphatic vessels; hence it has been termed the crihriform
fascia, the o])cnings of these vessels having been likened to the holes in a sieve.
The cribriform fascia adheres closely both to the superficial foscia and the fascia
lata, so that it is described by some"^ anatomists as a part of the fascia lata, but
is usually considered (as in this work) as belonging to the superficial fascia. It
is not till the cribriform fascia has been cleared away, that the saphenous opening
is seen, so that this opening does not, in ordinary cases, exist naturally, but is
the result of dissection. Mr. Callendcr, liowcvcr, speaks c^f cases in winch,
probably as the result of pressure from enlarged inguinal glands, the fascia has
become atrophied, and a sa])]ionous opening exists independent of dissection.^
' Anatuiny {)[ Fciiiurul Uuplurc, note on p. 18.
FEMORAL HERNIA. 889
A femoral hernia, in passing tlirougli the saphenous opening, receives the
cribriform fascia as one of its coverings.
The deep layer of superficial fascia, together with the cribriform fascia, having
been removed, the fascia lata is exposed.
The Fascia Lata^ already described (p. 433), is a dense fibrous aponeurosis,
which forms a uniform investment for the whole of this region of the limb. At
the upper and inner part of the thigh, a large oval-shaped aperture is observed
in it; it transmits the internal saphenous vein and other small vessels, and is
called the saphenous opening. In order the more correctly to consider the mode
of formation of this aperture, the fascia lata in this part of the thigh is described
as consisting of two portions, an iliac portion and a pubic portion.
The iliac portion of the fascia lata is situated on the outer side of the saphe-
nous opening covering the outer surface of the Sartorius, the Eectus, and the
Psoas and Iliacus muscles. It is attached externally to the crest of the ilium
and its anterior superior spine, to the whole length of Poupart's ligament as far
internally at the spine of the pubes, and to the pectineal line in conjunction
with Gimbernat's ligament, where it becomes continuous with the pubic portion.
From the spine of the pubes, it is reflected downwards and outwards, forming
an arched margin, the outer boundary {superior cornu) of the saphenous opening.
This is sometimes called the falciform process of the fascia lata (femoral ligament
of Hey) ; it overlies, and is adherent to, the sheath of the femoral vessels beneath ;
to its edo-e is attached the cribriform fascia, and it is continuous below with the
pubic portion of the fascia lata by a well-defined curved margin.
The puhic portio7i of the fascia lata is situated at the inner side of the saphe-
nous opening : at the lower margin of this aperture, it is continuous with the
iliac portion : traced upwards, it covers the surface of the Pectineus, Adductor
longus, and Gracilis muscles: and passing behind the sheath of the femoral
vessels, to which it is closely united, is continuous with the sheath of the Psoas
and Iliacus muscles, and is finally lost in the fibrous capsule of the hip-joint.
This fascia is attached above to the pectineal line, and internally to the margin
of the pubic arch. It may be observed from this description that the iliac
portion of the fascia lata passes in front of the femoral vessels, the pubic portion
behind them; an apparent aperture consequently exists between the two, through
which the internal saphenous joins the femoral vein.
The /Saphenous Opening is an oval -shaped aperture, measuring about an inch
and a half in length, and half an inch in width. It is situated at the upper and
inner part of the thigh, below Poupart's ligament, towards the inner side, and
is directed obliquely downwards and outwards.
Its outer margin is of a semilunar form, thin, strong, sharply defined, and lies
on a plane considerably anterior to the inner margin. If this edge is traced
upwards, it will be seen to form a curved elongated process or cornu (the supe-
rior cornu), OT falciform process of Buriis, which ascends in front of the femoral
vessels, and curving inwards, is attached to Poupart's ligament and to the spine
of the pubes and pectineal line, where it is continuous with the pubic portion.^
' It is difficult to perceive in the recognizee! description of these ligaments (Hey's and Burns's)
any difference between the two ; nor is it clear what structure Mr. Hey really intended to describe.
Mr. Gay (on ''Femoral Rupture," p. 16) gives very cogent reasons "for thinking that the " deep
crural arch" was the structure which Hey had in view. The most recent writer on Femoral
Hernia speaks thus while treating of these parts : " The whole upper edge of the iliac fascia lata
is commonly called the ' falciform process.' whilst its deeper fibres receive the name of 'Burns's
ligament.' Hey's femoral ligament would appear to consist of distinct fibres connected with the
inner fold of the iliac fascia, which extend immediately beneath the tendon of the external oblique
to the subperitoneal fascia." (Caij.endrr. "On the Anatomy of the Parts Concerned in Femo-
ral Rupture" p. 19, note.) This description of Hey's ligament accords closely with that of the
deep crural arch, for the subperitoneal fascia is Mr. Callender's name for the fascia transversalis.
Mr. Callender goes on to say, " The upper border of this (saphenous) opening thus receives, by
an unfortunate complication, the names of * Falciform process.' ' Femoral ligament,' Burns's or
Hey's ligament.' The various divisions of the iliac fascia lata depend in great measure upon the
sliill of the dissector, and are, in my opinion, artificial."
890
SUEGICAL ANATOMY OF INGUINAL HERNIA.
If traced downwards, it is found continuous with another curved margin, the
concavity of which is directed upwards and inwards : this is the inferior cornu
of the saphenous opening, and is blended with the pubic portion of the fascia
lata covering the Pectineus muscle.
The inner houndary of the opening is on a plane posterior to the outer margin,
and behind the level of the femoral vessels ; it is much less prominent and defined
than the outer, from being stretched over the subjacent Pectineus muscle. It is
through the saphenous opening that a femoral hernia passes after descending
along the crural canal.
If the finger is introduced into the saphenous opening while the limb is moved
in different directions, the aperture will be found to be greatly constricted on
extending the limb, or rotating it outwards, and to be relaxed on flexing the
limb and inverting it: hence the necessity for placing the limb in the latter
position in employing the taxis for the reduction of a femoral hernia.
The iliac portion of the fascia lata, together with its falciform process, should now be removed,
by detaching it from the lower margin of Poupart's ligament, carefully dissecting it from the
subjacent structures, and turning it aside when the sheath of the femoral vessels is exposed
descending beneath Poupart's ligament (Fig. 511).
Fig. 511. — Femoral Hernia. Iliac Portion of Fascia Lata removed, and Sheath of
Femoral Vessels and Femoi-al Canal exposed.
The Crvral Arch, or PovparCs TAfiamont^ is the lower border of tlic aponeu-
rosis of the Ext(!nial obli(|ii(> muscle, which stretches across from the anterior
superior spine of 1lif, ilium, to iIk^ spine of the os pubis and pectineal line: the
portion corresponding to llic lallcr insertion is called Oimhernat^s Ligament.
The direction of Poupart's ligament is curved downwards towards the thigh ;
FEMORAL HERNIA. 891
its outer half being oblique, its inner lialf nearly horizontal. Nearly the whole
of the space included between the crural arch and innominate bone is filled in
by the parts which descend from the abdomen into the thigh. The outer half
of the space is occupied by the Iliacus and Psoas muscles, together with the
external cutaneous and anterior crural nerves. The pubic side of the space is
occupied by the femoral vessels included in their sheath, a small oval-shaped
interval existing between the femoral vein and the inner wall of the sheath,
which is occupied merely by a little loose areolar tissue, and occasionally by a
small lymphatic gland : this is the criiral canal, along which the gut descends
in femoral hernia.
Qimbernafs Ligament (Fig. 512) is that j^art of the aponeurosis of the External
oblique muscle which is reflected downwards and outwards, to be inserted into
the pectineal line of the os pubis. It is about an inch in length, larger in the
male than in the female, almost horizontal in direction in the erect posture, and
of a triangular form, the base directed outwards. Its hase^ or outer margin, is
concave, thin, and sharp, lies in contact with the crural sheath, and is blended
with the pubic portion of the fascia lata. Its a-pex corresponds to the spine of
the pubes. Its posterior margin is attached to the pectineal line. Its anterior
margin is continuous with Poupart's ligament.
Crural Sheath. If Poupart's ligament is divided, the femoral or crural sheath
may be demonstrated as a continuation downwards of the fasciae that line the
abdomen, the transversalis fascia passing down in front of the femoral vessels,
and the iliac fascia descending behind them ; these fascise are directly continuous
on the iliac side of the femoral artery, but a small space exists between the
femoral vein and the point where they are continuous on the pubic side of that
vessel, which constitutes the femoral or crural canal. The femoral sheath is
closely adherent to the contained vessels about an inch below the saphenous
opening, becoming blended with the areolar sheath of the vessels, but opposite
Poupart's ligament it is much larger than is required to contain them; hence
the funnel-shaped form which it presents. The outer border of the sheath is
perforated by the genito-crural nerve. Its inner border is pierced by the in-
ternal saphenous vein, and numerous lymphatic vessels. In front, it is covered
by the iliac portion of the fascia lata ; and behind it is the pubic portion of the
same fascia.
Deep Crural Arch. Passing across the front of the crural sheath, and closely
connected with it, is a thickened band of fibres, called the deep crural arch. It
is apparently a thickening of the fascia transversalis, joining externally to the
centre of Poupart's ligament, and arching across the front of the crural sheath,
to be inserted by a broad attachment into the pectineal line, behind the conjoined
tendon. In some subjects, this structure is not very prominently marked, and
not unfrequently it is altogether wanting.
If the anterior wall of the sheath is removed, the femoral artery and vein are
seen lying side by side, a thin septum separating the two vessels, while another
septum separates the vein from the inner wall of the sheath. The septa are
stretched between the anterior and posterior walls of the sheath, so that each
vessel is inclosed in a separate compartment. The interval left between the vein
and the inner wall of the sheath is not filled up by any structure, excepting a
little loose areolar tissue, a few lymphatic vessels, and occasionally a lymphatic
gland ; this is the femoral or crural canal, through which the intestine descends
in femoral hernia.
The crural canal is the narrow interval between the femoral vein and the inner
wall of the crural sheath. It exists as a distinct canal only when the sheath has
been separated from the vein by dissection, or by the pressure of a hernia or
tumor. Its length is from a quarter to half an inch, and it extends from Gim-
bernat's ligament to the ujDper part of the saphenous opening.
Its anterior ivall is very narrow, and formed by the fascia transversalis, Pou-
part's ligament, and the falciform process of the fascia lata.
892
SURGICAL ANATOMY OF INGUINAL HERNIA,
li& posterior wall is formed by the iliac fascia and the pubic portion of the
fascia lata.
Its outer ivall is formed bj the fibrous septum covering the inner side of the
femoral vein.
Its irmer ivall is formed by the junction of the transversalis and iliac fasciae,
which form the inner side of the femoral sheath, and cover the outer edo-e of
Gimbernat's ligament.
This canal has two orifices : a lower one, the saphenous opening^ closed by the
cribriform fascia; an upper one, the /emoraZ or crural ring^ closed by the septum
crurale.
Fig. 512.— Hernia. The Relations of the Femoral and Internal Abdominal Ring,
seen from within the Abdomen. Right Side.
The femoral or crural ring (Fig. 512) is the upper opening of the femoral
canal, and leads into the cavity of the abdomen.^ It is bounded in front by
Poupart's ligament and the deep crural arch ; behind by the pubes, covered by
the Pectineus muscle, and the pubic portion of the fascia lata ; internally, by
Gimbernat's ligament, the conjoined tendon, the transversalis fascia, and the
deep crural arch; externally, by the femoral vein, covered by its sheath. The
femoral ring is of an oval form ; its long diameter, directed transversely, measures
about half an inch, and it is larger in the female than in the male, which is one
of the reasons of the greater frequency of femoral hernia in the former sex.
Position of Parts around the Ring. The spermatic cord in the male, and round
ligament in tlie female, lie immediately above the anterior margin of the femoral
ring, and may be divided in an operation for femoral hernia if the incision for
the relief of the stricture is not of limited extent. In the female, this is of
little importance, but in the male the spermatic artery and vas deferens may be
divided.
T\\c, femoral veiyi lies on the outer side of the ring.
The epigastric artery, in its passage inwards from the external iliac to the
umbilicus, passes across the upper and outer angle of the crural ring, and is con-
sequently in danger of being wounded if the stricture is divided in a direction
upwards and outwards.
' Tlif^ rintr. lilio 1lio fniriil onnnl. is a nu)r))i(l or nn nrlificinl jirodnct. " Facli fenionil lii'rnia
makes for itself (for ncitiier (nillct exists in th(( natural anatomy of the region) a crural canal,
and a crural (femoral) ring." — C/\i.r,ENDKii, op. cil., p. 40.
FEMORAL HERNIA. 893
The communicating branch between the epigastric and obturator lies in front
of the ring.
The circumference of the ring is thus seen to be bounded by vessels in every
part, excepting internally and behind. It is in the former position that the
stricture is divided in cases of strangulated femoral hernia.
The obturator artery^ when it arises by a common trunk with the epigastric,
which occurs once in every three subjects and half, bears a very important rela-
tion to the crural ring. In some cases it descends on the inner side of the ex-
ternal iliac vein to the obturator foramen, and will consequently lie on the outer
side of the crural ring, where there is no danger of its being wounded in the
operation for dividing the stricture in femoral hernia. (See Fig. 325, p. 540, 1st
Fig.) Occasionally, however, the obturator artery curves along the free margin
of Gimbernat's ligament in its passage to the obturator foramen ; it would, con-
sequently, skirt along the greater part of the circumference of the crural canal,
and could hardly avoid being wounded in the operation. (See Fig. 325, p. 540,
2d Fig.)
Septum Crurale. The femoral ring is closed by a layer of condensed areolar
tissue, called, by J. Cloquet, the septum crurale. This serves as a barrier to the
protrusion of a hernia through this part. Its upper surface is slightly concave,
and supports a small lymphatic gland, by which it is separated from the sub-
serous areolar tissue and peritoneum. Its under surface is turned towards the
femoral canal. The septum crurale is perforated by numerous apertures for the
passage of lymphatic vessels, connecting the deep inguinal glands with those
surrounding the external iliac artery.
The size of the femoral canal, the degree of tension of its orifices, and, con-
sequently, the degree of constriction of a hernia, vary according to the position
of the limb. If the leg and thigh are extended, abducted, or everted, the
femoral canal and its orifices are rendered tense, from the traction on these parts
by Poupart's ligament and the fascia lata, as may be ascertained by passing the
finger along the canal. If, on the contrary, the thigh is flexed upon the pelvis,
and, at the same time, adducted and rotated inwards, the femoral canal and its
orifices become considerably relaxed ; for this reason, the limb should always
be placed in the latter position when the application of the taxis is made in
attempting the reduction of a femoral hernia.
The septum crurale is separated from the peritoneum by a quantity of loose
subserous areolar tissue. In some subjects, this tissue contains a considerable
amount of adipose substance, which, when protruded forwards in front of the
sac of a femoral hernia, may be mistaken for a portion of omentum.
Descent of the Hernia. From the preceding description it follows, that the
femoral ring must be a weak point in the abdominal wall : hence it is, that when
violent or long-continued pressure is made upon the abdominal viscera, a por-
tion of intestine may be forced into it, constituting a femoral hernia ; and the
changes in the tissues of the abdomen which are produced by pregnancy, to-
gether with the larger size of this aperture in the female, serve to explain the
frequency of this form of hernia in women.
When a portion of intestine is forced through the femoral ring, it carries
before it a pouch of peritoneum, wliicli forms what is called the hernial sac ; it
receives an investment from the subserous areolar tissue, and from the septum
crurale, and descends vertically along the crural canal in the inner compartment
of the sheath of the femoral vessels as far as the saphenous opening ; at this
point, it changes its course, being prevented from extending further down the
sheath, on account of the narrowing of the sheath and its close contact with the
vessels, and also from the close attachment of the superficial fascia and crural
sheath to the lower part of the circumference of the saphenous opening ; the
tumor is, consequently, directed forwards, pushing before it the cribriform fascia,
and then curves upwards on to the falciform process of the fascia lata and lower
part of the tendon of the External oblique, being covered by the superficial
894 SURGICAL ANATOMY OF INGUINAL HERNIA.
fascia and integument. Wliile tlie hernia is contained in the femoral canal, it
is usually of small size, owing to the resisting nature of the surrounding parts ;
but when it has escaped from the saphenous opening into the loose areolar
tissue of the groin, it becomes considerably enlarged. The direction taken by
a femoral hernia in its descent is at first downwards, then forwards and up-
wards ; this should be borne in mind, as in the application of the taxis for the
reduction of a femoral hernia, pressure should be directed in the reverse order.
Coverings of the Hernia. The coverings of a femoral hernia from within out-
wards are peritoneum, subserous areolar tissue, the septum crurale, crural
sheath, cribriform fascia, superficial fascia, and integument.^
Varieties of Femoral Hernia. If the intestine descends along the femoral
canal only as far as the saphenous opening, and does not escape from this
aperture, it is called incom'plete femoral hernia. The small size of the protrusion
in this form of hernia, on account of the firm and resisting nature of the canal in
which it is contained, renders it an exceedingly dangerous variety of the disease,
from the extreme difiiculty of detecting the existence of the swelling, especially
in corpulent subjects. The coverings of an incomplete femoral hernia would
be, from without inwards, integument, superficial fascia, falciform process of
fascia lata, fascia propria, septum crurale, subserous cellular tissue, and perito-
neum. When, however, the hernia tumor protrudes through the saphenous
opening, and directs itself forwards and upwards, it forms a complete femoral
hernia. Occasionally, the hernial sac descends on the iliac side of the femoral
vessels, or in front of these vessels, or even sometimes behind them.
The seat of stricture of a femoral hernia varies : it may be in the peritoneum
at the neck of the hernial sac ; in the greater number of cases it would appear
to be at the point of junction of the falciform process of the fascia lata with the
lunated edge of Gimbernat's ligament ; or at the margin of the saphenous open-
ing in the thigh. The stricture should in every case be divided in a direction "
upwards and inwards ; and the extent necessary in the majority of cases is about
two or three lines. By these means, all vessels or other structures of importance,
in relation with the neck of the hernial sac, will be avoided.
' Sir A. Cooper has described an investment for femoral hernia under the name of " Fascia
propria," lyinp immediately external to the peritoneal sac, but frequently separated from it by
more or less adipose tissue. Surgically, it is important to remember the existence (at any rate,
the occasional existence) of this layer, on account of the ease with which an inexperienced
operator may mistake the fascia for the peritoneal sac, and the contained fat for omentum.
Anatomically, this fascia appears identical with what is called in the text " subserous areolar
tissue," the areolar tissue being thickened and caused to assume a membranous appearance, by
the pressure of the hernia.
Surgical Anatomy of the Perineum and Ischio-
rectal Region.
Dissection. — The student should select a well-developed muscular subject, free from fat, and
the dissection should be commenced early, in order that the parts may be examined in as recent a
state as possible. A staff having been introduced into the bladder, and the subject placed in the
position shown in Fig. 513, the scrotum should be raised upwards, and retained in that position,
and the rectum moderately distended with tow.
The space whicli is now exposed, corresponds to tlie inferior aperture, or out-
let of tlie pelvis. Its deep boundaries are, in front, the pubic arch and subpubic
ligament ; behind, the tip of the coccyx ; and on each side, the ramus of the
pubes and ischium, the tuberosity of the ischium, and great sacro-sciatic liga-
ment. The space included by these boundaries is somewhat lozenge-shaped, and
is limited on the surface of the body by the scrotum in front, by the buttocks
behind, and on each side by the inner side of the thighs. It measures, from
before backwards, about four inches, and about three in the broadest part of its
transverse diameter, between the ischial tuberosities. A line drawn transversely
between the anterior part of the tuberosity of the ischium, on each side, in front
of the anus, subdivides this space into two portions. The anterior portion con-
tains the penis and urethra, and is called the perineum. The posterior portion
contains the termination of the rectum, and is called the ischio-rectal region.
ISCHIO-EECTAL EeG-ION.
The Ischio-rectal Region corresponds to the portion of the outlet of the pelvis
situated immediately behind the perineum : it contains the termination of the
rectum. A deep fossa, filled with fat, is seen on either side of the intestine,
between it and the tuberosity of the ischium : this is called the ischio-rectal
fossa.
The ischio-rectal region presents, in the middle line, the aperture of the anus ;
around this orifice, the integument is thrown into numerous folds, which are
obliterated on distension of the intestine. The integument is of a dark color,
continuous with the mucous membrane of the rectum, and provided with nume-
rous follicles, which occasionally inflame and suppurate, and may be mistaken
for fistulas. The veins around the margin of the anus are occasionally much
dilated, forming a number of hard, pendent masses, of a dark bluish color, cov-
ered partly by mucous membrane, and partly by the integument. These
tumors constitute the disease called external piles.
Dissection. — Make an incision through the integument, along the median line, from the base
of the scrotum to the anterior extremity of the anus ; carry it round the margins of this aperture
to its posterior extremity, and continue it backwards about an inch behind the tip of the coccyx.
A transverse incision should now be carried across the base of the scrotum, joining the anterior
extremity of the preceding ; a second, carried in the same direction, should be made in front of the
anus ; and a third at the posterior extremity of the gut. These incisions shonld be sufiRciently
extensive to enable the dissector to raise the integument from the inner side of the thighs. The
flaps of skin corresponding to the ischio-rectal region (Figs. 513-517), should now be removed.
In dissecting the integument from this region, great care is required, otherwise the External
sphincter will be removed, as it is intimately adherent to the skin.
The superficial fascia is exposed on the removal of the skin: it is very thick,
areolar in texture, and contains much fat in its meshes. In it are found rami-
fvina; two or three cutaneous branches of the small sciatic nerve; these turn
(895)
896 SURGICAL ANATOMY OF THE PERINEUM.
round the inferior border of the Gluteus maximus, and are distributed to tlie
integument in tliis region.
Fig. 513. — Dissection of Perineum and Ischio-rectal Region.
The External sphincter is a thin flat plane of muscular fibres, elliptical in
shape, and intimately adherent to the integument surrounding the margin of the
anus. It measures about three or four inches in length, from its anterior to its
posterior extremity,being about an inch in breadth, opposite the anus. It arises
from the tip of the coccyx, by a narrow tendinous band ; and from the superficial
fascia in front of that bone ; and is inserted into the tendinous centre of the peri-
neum, joining with the Transversus perinsei, the Levator ani, and the Accelera-
tor iirinse. Like other Sphincter muscles, it consists of two planes of muscular,
fibre, which surround the margin of the anus, and join in a commissure before
and behind.
Relations. By its superficial surface^ with the integument; by its deep surface^
it is in contact with the Internal sphincter ; and is separated from the Levator
ani by loose areolar tissue.
The Sphincter ani is a voluntary muscle, supplied by the hemorrhoidal branch
of the fourth sacral nerve. This muscle is divided in the operation for fistula
in ano ; and also in some cases of fissure of the rectum, especially if attended
with much pain or spasm. The object of its division is to keep the parts at
rest and in contact during the healing process.
The Internal sphincter is a muscular ring, about an inch in breadth, which
surrounds the lower extremity of the rectum, about an inch from the margin of
the anus. This muscle is about two lines in thickness, and is formed by an
aggregation of the involuntary circular fibres of the intestine. It is paler in
color, and less coarse in texture, than the External sphincter.
The ischio-rectal fossa is situated between the end of the rectum and the tube-
rosity of the ischium on each side. It is triangular in shape, its base, directed
to the surface of the body, is formed by the integument of the ischio-rectal
region ; its apex, directed upwards, corresponds to the point of division of the
obturator fascia, and the thin membrane given off from it, which covers the
outer surface of the Levator ani (ischio-rectal fascia). Its dimensions are about
an inch in breadth, at the base, and about two inches in depth, being deeper
behind than in front. It is bounded, internally^ by the Sphincter ani. Levator
ani, and Coccygeus muscles; externally^ by the tuberosity of the ischium, and
the obturator fascia, which covers the inner surface of the Obturator internus
muscle; in front ^ it is limited by the line of junction of the superficial and deep
perineal fasciae : and hehind^ by the margin of the Gluteus maximus, and the
great sacro-sciatic ligament. This space is filled with a large ]nass of adipose
substance, which ex})lains the frequency with which abscesses in the neighbor-
hood of the rectum burrow to a considerable depth.
SUPERFICIAL FASCIA. 897
If tlie subject has been injected, on placing the finger on the outer wall of this
fossa, the internal pudic artery, with its accompanying veins and nerve, will be
felt about an inch and a half above the margin of the ischiatic tuberosity, but
approaching nearer the surface as they pass forwards along the inner margin of
the pubic arch. These structures are inclosed in a sheath formed by the obtu-
rator fascia, the pudic nerve lying below the artery. Crossing the space trans-
versely, about its centre, are the inferior htemorrhoidal vessels and nerves, branches
of the pudic ; they are distributed to the integument of the anus, and to the
muscles of the lower end of the rectum. These vessels are occasionally of larger
size, and may give rise to troublesome hemorrhage, when divided in the opera-
tion of lithotomy, or of fistula in ano. At the back part of this space may be
seen a branch of the fourth sacral nerve ; and, at the fore part of the space, a
cutaneous branch of the perineal nerve.
Perineum.
The Perineal Space is of a triangular form ; its deep boundaries are limited,
laterally, by the rami of the pubes and ischia, meeting in front at the pubic arch ;
behind by an imaginary transverse line, extending between the tuberosities of
the ischia. The lateral boundaries vary, in the adult, from three inches to three
inches and a half in length ; and the base from two to three inches and a half in
breadth ; the average extent of the base being two inches and three-quarters.
The variations in the diameter of this space are of extreme interest in connec-
tion with the operation of lithotomy, and the extraction of a stone from the
cavity of the bladder. In those cases where the tuberosities of the ischia are
near together, it would be necessary to make the incisions in the lateral opera-
tion of lithotomy less oblique than if the tuberosities were widely separated, and
the perineal space, consequently, wider. The perineum is subdivided by the
median raphe into two equal parts. Of these, the left is the one in which the
operation of lithotomy is performed.
In the middle line, the perineum is convex, and corresponds to the bulb of the
urethra. The skin covering it is of a dark color, thin, freely movable upon the
subjacent parts, and covered with sharp crisp hairs which should be removed
before the dissection of the part is commenced. In front of the anus, a promi-
nent line commences, the raphe, continuous in front with the raphe of the scro-
tum. The flaps of integument corresponding to this space having been removed,
in the manner shown in Figs. 513-16, the suiDerficial fascia is exposed.
The Superficial Fascia consists of two layers, superficial and deep, as in other
regions of the body.
The sii2Derficial layer is thick, loose, areolar in texture, and contains much
adipose tissue in its meshes, the amount of which varies in different subjects.
In front it is continuous with the dartos of the scrotum. ; behind, it is continuous
with the subcutaneous areolar tissue surrounding the anus ; and, on either side,
with the same fascia on the inner side of the thighs. This layer should be care-
fully removed, after it has been examined, when the deep layer will be exposed.
The deep layer (superficial perineal fascia) is thin, aponeurotic in structure,
and of considerable strength, serving to bind down the muscles of the root of
the penis. It is continuous, in frdnt, with the dartos of the scrotum ; on either
side, it is firmly attached to the margins of the rami of the pubes and ischium,
external to the crus penis, and as far back as the tuberosity of the ischium ;
posteriorly it curves down behind the Transversus perineei muscles to join the
lower margin of the deep perineal fascia. This fascia not only covers the mus-
cles in this region, but sends down a vertical septum from its under surface,
which separates the back part of the subjacent space into two, being incomplete
in front.
In rupture of the anterior portion of the urethra, accompanied by extravasa-
tion of urine, the fluid makes its way forwards, beneath this fascia, into the
57
898. SURGICAL ANATOMY OF THE PERINEUM.
areolar tissue of the scrotum, penis, and anterior and lateral portions of tlie
abdomen ; it rarely extends into tlie areolar tissue on the inner side of the thighs
or backwards around the anus. This limitation of the extravasated fluid to the
parts above named is easy of explanation, when the attachments of the deep
Fig 514. — The Perineum. The Integument and Superficial Layer of
Superficial Fascia reflecteJ.
layer of the superficial fascia are considered. When this fascia is removed the
muscles connected with the penis and urethra will be exposed ; these are, in the
middle line, the Accelerator urina3; on each side, the Erector penis, and behind
the Trans versus perinsei.
The Accelerator urinse is placed in the middle line of the perineum, imme-
diately in front of the anus. It consists of two symmetrical halves, united along
the median line by a tendinous raphe. It arises from the central tendon of the
perineum, and from the median raphe in front. From this point its fibres diverge
like the plumes of a pen ; the most posterior form a thin layer, which are lost
on the anterior surface of the triangular ligament; the middle fibres encircle the
bulb and adjacent part of the corpus spongiosum, and join with the fibres of the
opposite side, on the upper part of the corpus spongiosum, in a strong aponeu-
rosis; the anterior fibres, the longest and most distinct, spread out over the
sides of the corpus cavernosum, to be insertetl partly into that body, anterior to
the Erector penis; partly terminating in a tendinous expansion, which covers
the dorsal vessels of the penis. The latter fibres are best seen by dividing the
muscle longitudinally, and dissecting it outwards from the surface of the urethra.
Action. This muscle may serve to accelerate the flow of the urine or semen
along the canal of the urethra. The middle fibres arc supposed, by Krause, to
assist in the erection of the corpus spongiosum, by compressing the erectile tissue
of the bulb. The anterior fibres, according to Tyrrcl, also contribute to the
erection of the penis, as they are inserted into, and continuous with, the fascia of
the penis, compressing the dorsal vein during the contraction of the muscle.
TRANSVERSUS PERIN^I.
899
The Erector penis covers the unattacTied part of the crus penis. It is an
elongated muscle, broader in the middle than at either extremity, and situated
on either side of the lateral boundary of the perineum. It arises by tendinous
and fleshy fibres from the inner surface of the tuberosity of the ischium, behind
Fig. 515. — The Superficial Muscles and Vessels of the Periueum.
&/■* Sacro -Sciatic Ligt-
^ Superficial Perinea/ Artery
-Superficia.1 Perineal Jferve
In-ternai fudic Ne-rve
■Internal Fadic Arte.ry
the crus penis, from the surface of the crus, and from the adjacent portion of the
ramus of the pubes. From these points, fleshy fibres succeed, which end in an
aponeurosis which is inserted into the side and under surface of the crus penis.
This muscle compresses the crus penis, and thus serves to maintain the organ
erect.
The Transversus perinsei is a narrow muscular slip, which passes more or less
transversely across the back part of the perineal space. It arises by a small
tendon from the inner and fore side of the tuberosity of the ischium, and pass-
ing obliquely forwards and inwards, is inserted into the central tendinous point
of the perineum, joining in this situation with the muscle of the opposite side,
the Sphincter ani behind, and the Accelerator urinse in front.
Between the muscles just examined, a triangular space exists, bounded inter-
nally by the Accelerator urinse, externally by the Erector penis, and behind by
the Transversus perinsei. The floor of this space is formed by the triangular
ligament of the urethra {deep perineal fascia), and, running from behind for-
wards in it, are the superficial perineal vessels and nerves, the transverse peri-
neal artery coursing along the posterior boundary of the space, on the Trans-
versus perinsei muscle.
In the lateral operation of lithotomy, the knife is carried obliquely across the
back part of this space, downwards and outwards, into the ischio-rectal fossa,
dividing the Transversus perineei muscle and artery, the posterior fibres of the
Accelerator urinse, the superficial perineal vessels and nerves, and more poste-
riorly the external hemorrhoidal vessels.
The superficial and transverse perineal arteries are described at p. 541 ; and
the superficial perineal and inferior pudendal nerves at pp. 690, 692.
900
SURGICAL ANATOMY OF THE PERINEUM.
The muscles of the perineum in the female are, the
Sphincter vaginas.
Erector clitoridis.
Transverse perinsei.
Coccygeus,
Compressor urethr^e.
Sphincter ani.
Levator ani.
The Sphincter vayinse surrounds the orifice of the vagina, and is analogous to
the Accelerator urinse in the male. It is attached, posteriorly, to the central
tendon of perineum, where it blends with the Sphincter ani. Its fibres pass
forward on each side of the vagina, to be inserted into the corpora cavernosa
and body of the clitoris.
The Erector clitoridis resembles the Erector penis in the male, but is smaller
than it.
The Transversus perinsei is inserted into the side of the Sphincter vaginse, and
the Levator ani into the side of the vagina. The other muscles are precisely
similar to those in the male.
The Accelerator uriiiae and Erector penis muscles slioiild now be removed, when the deep peri-
neal fascia will be exposed, stretching across the front part of the outlet of the pelvis. The
urethra is seen perforating its centre, just behind the bulb; and on either side is the crus penis,
connecting the corpus cavernosum with the ramus of the ischium aud pubes.
Fig. 516.— Deep Perineal Fascia. On the left side, the anterior laj-er has been removed.
Antcr 10 r L aye r of-
D(ep. Perineal Fascia remcvaa
Shewing
- COMPRESSOR URETHRAS
- Jniernal PudU ArtV.
— Arty €f the Bu.li
- Corvjurs Glaiul
y
The Deej) Perineal fascia (triangular ligament), is a dense membranous
lamina, wliich closes the front part of the outlet of the pelvis. It is triangular
in shape, about an inch and a half in depth, attached above, by its apex, to the
under surface of the symphysis pubis and subpubic ligament ; and, on each side,
to the rami of the ischium and pubes, beneath the crura penis. Its inferior
margin', or base, is directed towards the rectum, and connected to the central
tendinf)us point of the perineum. It is continuous with the deep layer of the
superficial fascia bcliind llie Transversus pcrimci muscle, and with a thin fascia
which covers the cutaneous surface of the Lcvat(3r ani muscle.
LEVATOR ANI. 901
The deep perineal fascia is perforated bj tlie iiretlira, about an incb below
the symphysis pubis. The aperture is circular in form, and about three or four
lines in diameter. Above this is the aperture for the dorsal vein of the penis ;
and, outside the latter, the pudic nerve and artery. pierce it.
The deep perineal fascia consists of two layers, anterior and posterior : these
are separated above, but united below.
The anterior layer is continued forwards, around the anterior part of the
membranou.s portion of the urethra, becoming lost upon the bulb.
1l\iq posterior ?a?/e7' is derived from the pelvic fascia; it is continued back-
wards around the posterior part of the membranous portion of the urethra and
the outer surface of the prostate gland.
If the anterior layer of this fascia is detached on either side, the following
parts are seen between it and the posterior layer : the subpubic ligament above,
close to the pubes ; the dorsal vein of the penis ; the membranous portion of the
urethra, and the muscles of the urethra ; Cowper's glands and their ducts ; the
pudic vessels and nerve ; the artery and nerve of the bulb, and a plexus of veins.
The Gom.pressor urethrse (constrictor urethrge) su,rrounds the whole length of
the membranous portion of the urethra, and is contained between the two layers
of the deep perineal fascia. It arises, by aponeurotic fibres, from the upper
part of the ramus of the pubes on each side, to the extent of half or three-quarters
of an inch : each segment of the muscle passes inwards, and divides into two
fasciculi, which surround the urethra from the prostate gland behind, to the
bulbous portion of the urethra in front ; and unite, at the upper and lower sur-
faces of this tube, with the muscle of the opposite side, by means of a tendinous
raphe.
Circular Muscular Fibres surround the membranous portion of the urethra
from the bulb in front to the prostate gland behind ; they are placed imme-
diately beneath the transverse fibres already described, and are continuous with
the circular fibres of the bladder. These fibres are involuntary.
Gowper''s Glands are situated immediately below the membranous portion of
the urethra, close behind the bulb, and below the artery of the bulb (p. 856).
The Pudic Vessels and Nerves are placed along the inner margin of the pubic
arch (p. 5-10).
The Artery of the Bulb passes transversely inwards, from the internal pudic
on the posterior margin of the triangular ligament, between the two layers of
fascia, accompanied by a branch of the pudic nerve (p. 542).
If the posterior layer of the deep perineal fascia is removed, and the cms
penis of one side detached from the bone, the under and perineal surface of the
Levator ani is brought fully into view. This muscle, with the triangular liga-
ment in front and the Coccygeus and Pyriformis behind, closes in the outlet of
the pelvis.
The Levator ani is a broad thin muscle, situated on each side of the pelvis.
It is attached to the inner surface of the sides of the true pelvis, and, descending,
unites with its fellow of the opposite side to form the floor of the pelvic cavity.
It supports the viscera in this cavity, and surrounds the various structures
which pass through it. It arises, in front from the posterior surface of the body
and ramus of the pubes, on the outer side of the symphysis; posteriorly, from
the inner surface of the spine of the ischium: and between these two points,
from the angle of division between the obturator and recto-vesical layers of the
pelvic fascia at their u^nder part : the fibres pass dowmvards to the middle line
of the floor of the pelvis, and are inserted, the most posterior fibres into the
sides of the apex of the coccyx ; those placed more anteriorly unite with the
muscle of the opposite side, in a median fibrous raphe, which extends between
the coccyx and the margin of the anus. The middle fibres, which form the
larger portion of the muscle, are inserted into the side of the rectum, blending
with the fibres of the Sphincter muscles; lastly, the anterior fibres, the longest,
descend upon the side of the prostate gland to unite beneath it with the muscle
902 SURGICAL ANATOMY OF THE PERINEUM.
of tlie opposite side, blending with the fibres of the external sphincter and
Transversus perin^i muscles at the tendinous centre of the perineum.
The anterior portion is occasionally separated from the rest of the muscle by
cellular tissue. From this circumstance, as well as from its peculiar relation
with the prostate gland, descending by its side, and surrounding it as in a sling,
it has been described by Santorini and others as a distinct muscle, under the
name of the Levator prostatse. In the female, the anterior fibres of the Levator
ani descend upon the sides of the vagina.
Relations. By its upper or pelvic surface with the recto-vesical fascia, which
separates it from the viscera of the pelvis and from the peritoneum. By its
outer or perineal surface.^ it forms the inner boundary of the ischio-rectal fossa,
and is covered by a quantity of fat, and by a thin layer of fascia continued from
the obturator fascia. Its posterior border is continuous with the Coccygeus
muscle. Its anterior harder is separated from the muscle of the opposite side by
a triangular space, through which the urethra, and in the female the vagina,
passes from the pelvis.
Actions. This muscle supports the lower end of the rectum and vagina, and
also the bladder during the efforts of expulsion.
The Coccygeus is situated behind and parallel with the preceding. It is a
triangular plane of muscular and tendinous fibres, arising, by its apex from the
spine of the ischium and lesser sacro-sciatic ligament, and inserted, by its base,
into the margin of the coccyx and into the side of the lower piece of the sacrum.
This muscle is continuous with the posterior border of the Levator ani, and
closes in the back part of the outlet of the pelvis.
Relations. By its inner or pelvic surface^ with the rectum.. By its external
surface^ with the lesser sacro-sciatic ligament. By its posterior horder^ with the
Pyriformis.
Action. The Coccygei muscles raise and support the coccyx, after it has been
pressed backwards during defecation or parturition.
Position of the Viscera at the Outlet of the Pelvis. Divide the central tendinous point of the
perineum, separate the rectum from its connection by dividing the fibres of the Levator ani,
which descend upon the sides of the prostate gland, and draw the gut backwards towards the
coccyx, when the under surface of the prostate gland, the neck and base of the bladder, the vesi-
culse seminales, and vasa deferentia will be exposed.
The Prostate Gland is placed immediately in front of the neck of the bladder,
around the prostatic portion of the urethra, its base being turned backwards
and its under surface towards the rectiim. It is retained in its position by the
Levator prostatge and by the pubo-prostatic ligaments, and is invested by a dense
fibrous covering, continued from the posterior layer of the deep perineal fascia.
The longest diameters of this gland are in the antero -posterior direction, and
transversely at its base ; and hence the greatest extent of incision that can be
made in it without dividing its substance completely across, is obliquely out-
wards and backwards. This is the direction in which the incision is made
through it in the operation of lithotomy, the extent of which should seldom ex-
ceed an inch in length. The relations of the prostate to the rectum should be
noticed; by means of the finger introduced into the gut, the surgeon detects
enlargement or other disease of this organ ; he is enabled also, by the same
means, to direct the point of a catheter when its introduction is attended with
much difficulty, either from injury or disease of the membranous or prostatic
portions of the urethra.
Behind tlic prostate is the posterior surface of the neck and base of the
bladder: a small triangular portion of this organ is seen, bounded, in front, by
the prostate gland ; behind, by the recto-vesical fold of the peritoneum ; on
either side, by the vesicular seminales and vasa deferentia ; and separated from
direct contact with the rectum by the recto-vesical fascia. The relation of this
})ortion of the bladder to the rectum is of extreme interest to the surgeon. In
cases of retention of urine this portion of the organ is found projecting into the
PARTS CONCERNED IN LITHOTOMY,
903
rectum, between tliree and four inches from tlie margin of tlie anus, and may
be easily perforated during life without injury to any important parts; this
portion of the bladder is, consequently, frequently selected for the performance
Fig. 517. — A Yiew of the Position of the Yiscera at the Outlet of the Pelvis.
Artert/ of Carpus Cavernosam.
lional Artery of Pents—frf , -^'^^
Artery of Bulb. '^ '
jTnfcj-Tial Fudie Artery '
Cou'jper's GZand^^ 'S
of the operation of tapping the bladder. If the finger is introduced into the
bowel, the surgeon may, in some cases, learn the position, as well as the size
and weight, of a calculus in the bladder ; and in the operation for its removal,
if, as is not unfrequently the case, it should be lodged behind an enlarged pros-
tate, it may be displaced from its positiou by pressing upwards the base of the
bladder from the rectum.
P arts concerned in the Operation of Lithotomy. The triangular ligament must
be replaced and the rectum drawn forwards so as to occupy its normal position.
The student should then consider the position of the various parts in reference
to the lateral operation of lithotomy. This operation is performed on the left
side of the perineum, as it is most convenient for the right hand of the operator.
A staff having been introduced into the bladder, the first incision is commenced
midway between the anus and the back of the scrotum (^. e., in an ordinary adult
perineum, about an inch and a half in front of the anus), a little on the left side
of the raphe, and carried obliquely backwards and outwards to midway between
the anus and tuberosity of the ischium. The incision divides the integument
and superficial fascia, the external hemorrhoidal vessels and nerves, and the
superficial and transverse perineal vessels ; if the fore-finger of the left hand
is thrust upwards and forwards into the wound, pressing at the same time
the rectum inwards and backwards, the staff may be felt in the membranous
portion of the urethra. The finger is fixed upon the staff", and the structures
covering it are divided with the point of the knife, Avhich must be directed along
the groove towards the bladder, the edge of the knife being carried outwards
and backwards, dividing in its course the membranous portion of the urethra,
and part of the left lobe of the prostate gland, to the extent of about an inch.
The knife is then withdrawn, and the fore-finger of the left hand passed along
904
PARTS CONCERNED IN LITHOTOMY
tlie staff into tlie bladder : tile staff liaving been "vvitlidrawn, and tlie position of
the stone ascertained, the forceps is introduced over the finger into the bladder.
If the stone is very large, the opposite side of the prostate may be notched before
the forceps is introduced : the finger is now withdrawn, and the blades of the
forceps opened and made to grasp the stone, which must be extracted by slow
and cautious undulating movements.
Parts divided in the operation. The various structures divided in this operation
are as follows : the integument, superficial fascia, external hemorrhoidal vessels
imd nerves, the posterior fibres of the Accelerator urinoa, the Transversus peri-
nei muscle and artery (and, probably, the superficial perineal vessels and nerves),
the deep perineal fascia, the anterior fibres of the Levator ani, part of the Com-
pressor urethrse, the membranous and prostatic portions of the urethra, and part
of the prostate gland.
F.'g. 518. — A Transverse Section of tlie Pelvis, showing the Pelvic Fascia.
A nterior CruralNer
""'/J, ofUC-^^
Parts to he avoided in the Operation. In making the necessary incisions in the
perineum for the extraction of a calculus, the following parts should be avoided.
The primary incisions should not be made too near the middle line, for fear
of wounding the bulb of the corpus spongiosum or the rectum; nor too far
externally, otherwise the pudic artery may be implicated as it ascends along the
inner border of the pubic arch. If the incisions are carried too far forwards,
the artery of the bulb may be divided ; if carried too far backwards, the entire
breadth of the prostate and neck of the bladder may be cut through, which allows
the urine to become infiltrated behind the pelvic fascia into the loose cellular
tissue between the bladder and rectum, instead of escaping externally ; diffuse
inflammation is consequently set up, and peritonitis from the close proximity of
the recto- vesical peritoneal fold is the consequence. If, on the contrary, the pros-
tate is divided in front of the base of the gland, the urine makes its way exter-
nally, and there is less danger of infiltration taking place.
During the operation it is of great importance that the finger should be passed
into the bladder hefore the staff is removed ; if this is neglected, and if the incis-
ion made through the prostate and neck of the bladder is too small, great diffi-
PELVIC FASCIA.
905
cultj may be experienced in introducing tlie finger afterwards; and in tliecliild,
where the connections of the bladder to the surrounding parts are very loose,
the force made in the attempt is sufficient to displace the bladder up into the
abdomen, out of the reach of the operator. Such a proceeding has not unfre-
quently occurred, producing the most embarrassing results, and total failure of
the operation.
Fig. 519. — Side View of the Pelvic Viscera of the Male Subject, showing the Pelvic
and Perineal Fasciae.
It is necessary to bear in mind that the arteries in the perineum occasionally
take an abnormal course. Thus the artery of the bulb, when it arises, as some-
times happens, from the pudic opposite the tuber ischii, is liable to be wounded
in the operation for lithotomy, in its passage forwards to the bulb. The acces-
sory pudic may be divided near the posterior border of the prostate gland, if
this is completely cut across ; and the prostatic veins, especially in people ad-
vanced in life, are of large size, and give rise, when divided, to troublesome he-
morrhage.
Pelvic Fascia.
The Pelvic Fascia (Fig. 520) is a thin membrane which lines the whole of the
cavity of the pelvis, and is continuous with the transversalis and iliac fascia?.
It is attached to the brim of the pelvis for a short distance at the side of the
cavity, and to the inner surface of the bone round the attachment of the Obtu-
rator internus. At the posterior border of this muscle, it is continued backwards
as a very thin membrane in front of the Pyriformis muscle and sacral nerves,
behind the branches of the internal iliac artery and vein which perforate it, to
the front of the sacrum. In front it follows the attachment of the Obturator
internus to the bone, arches beneath the obturator vessels, completing the orifice
906
PELYIC FASCIA.
of tlie obturator canal, and at the front of the pelvis is attached to the lower part
of the symphysis pubis : being continuous below the pubes with the fascia of the
opposite side, so as to close the front part of the outlet of the pelvis, blending
with the posterior layer of the triangular ligament. At the level of a line ex-
tending from the lower part of the symphysis pubis to the spine of the ischium,
Fisr. 520.— Pelvic Fascia.
SPINE C
c PAJB=S
is a thickened whitish band; this marks the attachment of the Levator ani
muscle to the pelvic fascia and corresponds to its point of division into two layers,
the obturator and recto- vesical.
The ohtnralor fascia descends and covers the Obturator internus muscle. It-
is a direct continuation of the pelvic fascia below the white line above mentioned,
and is attached to the pubic arch and to the margin of the great sacro-sciatic
ligament. This fascia forms a canal for the pudic vessels and nerve in their pas-
sage forwards to the perineum, and is continuous with a thin membrane which
covers the perineal aspect of the Levator ani muscle, called the isclno-rectal (anal)
fascia.
Tlie recto-vesical fascia (visceral layer of the pelvic fascia) descends into the
pelvis upon the upper surface of the Levator ani muscle, and invests the pros-
tate, bladder, and rectum. From the inner surface of the symphysis pubis a
short rounded band is continued to the upper surface of the prostate and neck
PELVIC FASCIA. 907
of the bladder, forming the pubo-prostatic or anterior true ligaments of the
bladder. At the side, this fascia is connected to the side of the prostate, in-
closing this gland and the vesical prostatic plexus, and is continued upwards on
the surface of the bladder, forming the lateral true ligaments of the organ. An-
other prolongation invests the vesiculas seminales, and passes across between
the bladder and rectum, being continuous with the same fascia of the opposite
side. Another thin prolongation is reflected round the surface of the lower end
of the rectum. The Levator ani muscle arises from the point of division of the
pelvic fascia ; the visceral layer of the fascia descending upon and being inti-
mately adherent to the upper surface of the muscle, while the under surface of
the muscle is covered by a thin layer derived from the obturator fascia, called
the ischio-rectal or anal fascia. In the female, the vagina perforates the recto-
vesical fascia, and receives a prolongation from it.
LANDMARKS
MEDICAL AND SURGICAL
BY
LUTHEK HOLDER, F.E.C.S.,
VICE-PRESIDENT AND MEJIBEK OF THE COURT OF EXAMINERS OF THE ROYAL COLLEGE OF
SURGEONS OP ENGLAND ; SURGEON TO SAINT BARTHOLOMEW'S AND THE
FOUNDLING HOSPITALS ; AUTHOR OF ' ' HUMAN OSTEOLOGY, ' '
"a MANUAL OF THE DISSECTION OF THE
HUMAN BODY," ETC.
FKOM THE SECOI^D ENGLISH EDITION
^^CMrurgus mente prius et ocidis agat quam manu armata."
(909)
TO
THE STUDENTS
PAST ANT> PRESENT
SAIN^T BAETHOLOMEWS HOSPITAL
THESE "LAXDMAEKS" AEE
(IJIO)
Jel^itattiij
BY THEIR SINCERE FRIEND
THE AUTHOE.
PREFACE
TO THE FIRST EDITION
These "Landmarks" have already appeared in Saint Bartliolomew's Hos-
pital Eeports. They are now republished, with some additions, in the hope
that the J may be useful to others besides those for whom they were originally
intended.
My object has been to collect into a compact form the leading landmarks
which help practical surgeons in their daily work. Those relating to the chest
and abdomen have been ascertained, with as much precision as natural varia-
tions permit, by needles introduced in various directions.
I have to express my acknowledgments to Mr. Walsham and to Dr. GoDSOx
for their contributions.
65 GowER Stkeet : March, 1876.
TO THE SECOND EDITION.
The present Edition has been carefully revised, and no pains have been
spared to secure correctness.
It has been suggested that Diagrams should be introduced. The Author is
convinced that they would frustrate rather than forward his main object, which
is to urge Students to acquire the habit of making the eye and the hand work
together, and to educate the " touch" upon the normal living body.
Without such practical training, how can we reasonably expect to form a
correct diagnosis when called upon to examine an injury, or detect a disease ?
( 911 )
LANDMARKS,
MEDICAL AND SURGICAL
1. In clinical teaching, we often have occasion to point out, on the surface of
the living body, what may be called " medical and surgical landmarks." By
" landmarks" we mean surface-marks, such as lines, eminences, depressions,
which are guides to, or indications of, deeper-seated parts. This practice is not
only most usefal, but absolutely necessary ; because many even advanced stu-
dents of anatomy are not so ready as they ought to be in their recognition of
parts when covered by skin. Students who may be familiar enough with
bones, muscles, bloodvessels, or viscera in the dissected subject, are often sadly
at fault when they come to put this knowledge into practice.
For instance, ask a student to put his finger on the exact place where he
would feel for the head of the radius, the coracoid process of the scapula, the
tubercle of the scaphoid bone in the foot ; ask him to compress effectually one
of the main arteries; to chalk the line of its course; to map on the chest the
position of the heart and the several valves at its base ; to trace along the walls
of the chest the outline of the lungs and pleura ; to point out the bony promi-
nences about the joints, and their relative position in the different motions of
tlie joints ; test him about the muscles and tendons which can be seen or felt as
they stand out in relief or remain in repose ; let him introduce his finger into
the several orifices of the body, and say what parts are accessible to the touch: —
questions such as these, even a good anatomist, unaccustomed to deal with the
living subject, might possibly find himself at a loss to answer.
2. Our main object, therefore, is to induce in students the habit of looking at
the living body with anatomical eyes, and with eyes too at their fingers' ends.
The value of this habit cannot be too highly estimated. Is it not of the utmost
importance to an operating surgeon that he should have in his mind's eye the
various structures of the body as they lie grouped, connected, and working
together ? Should he not try at least to see them with the same clearness and
accuracy as if they were perfectly transparent ?
Moreover, the habit of examining the living body with " anatomical eyes"
and " surgical fingers" teaches the eye and the hand to act together, and trains
that delicate sense of touch Avhich every good surgeon should possess.
This habit is within easy reach of any one who has carefully dissected for
himself, and acquired the knowledge of Avhat to feel for. Plates will not give
it him. Let a student examine his own bod}^ with a skeleton before him. Better
still that two should work thus together, each serving as a " model" to the
other.
I would also invite teachers of anatomy to follow the example of Sir 0. Bell,
who was in the habit of introducing, from time to time, a powerful muscular
fellow to his class, " in order to show how much of the structure of the body,
68 (913)
9U LANDMARKS, MEDICAL AND SURGICAL.
such as tlie articulations and tlie muscles, might be learned without actual dis-
section."^
At the same time, it is only fair to say that "landmarks" cannot always be
defined with precision. A reasonable latitude must be allowed for natural
variations in different persons. Anatomy obvious to the eye and the finger
depends in great measure upon the quantity of subcutaneous fat. In some it
stands out beautifully clear; in others it is masked by obesity. Selecting,
therefore, for study a moderately lean person, let us begin with the head.
THE HEAD.
3. Scalp ; its density. — The great toughness of the scalp, more especially
at the back of the head, is owing to its intimate connection with the cranial
aponeurosis, the scalp vessels and hair bulbs intervening. This density often
obscures the diagnosis of tumors on the cranium. A tumor growing upon the
head may be either above or below the aponeurosis of the scalp. If below, it
will have a firm resisting feel, being bound down by the aponeurosis. JSTever-
theless its firmness and resistance may not depend simply on its confinement
beneath the aponeurosis, but on its having its origin within the skull. Look
with suspicion, then, on every tumor on the head that will not readily permit
you to move it about, so as to be sure of its connections prior to an attempt at
extirpation.
The scalp moves freely over the pericranium, to which it is very loosely con-
nected by areolar tissue. When suppuration takes place in this tissue free
incisions through the dense scalp must be made to let the pus out.
4. Arteries of Scalp. — The supra-orbital artery can be felt beating just,
above the supra-orbital notch, and traced for some way up the forehead ; the
temporal (anterior branch) ascends tortuously about an incli and a quarter
behind the external angular process of the frontal bone ; the occipital can be
felt near the middle of a line drawn from the occipital protuberance to the mas-
toid process ; the posterior auricular, near the apex of the mastoid process. All
these arteries can be effectually compressed against the subjacent bone.
5. Skullcap. — The skullcap is rarely quite symmetrical. This want of
symmetry is often obvious. It may occur in men highly gifted, as in the cele-
brated French anatomist Bichat. As to shape and relative dimensions, no two
heads are exactly alike, any more than two faces. It is beside my present pur-
pose to go into the question of craniology more than to say that, although the
cranium does not exactly follow the brain in all its eminence and depressions so
as to be like a cast of its surface, yet it certainly indicates the dimensions of the
great cerebral masses. The frontal and parietal eminences and the occipital
region may be taken as a general indication of the development of the corre-
sponding lobes of the brain. To ascertain the relative proportions of these
three regions, let a thread be passed from one meatus auditorius to the other,
across the frontal, parietal, and occipital eminences respectively.
Frontal Sinuses. — The "frontal sinuses" formed by the separation of the
two tahlcs of liic skidl vary mucli in size in different persons and at diilcrent
periods of life. This has an important bearing on wounds of the foreliead
and on trephining in this situation. These "bumps" do not exist in children
because the tables of the skull do not begin to separate before puberty. From
an examination of many skulls in the Iluntcrian Museum, I find that the
absence of the external prominence, even in middle age, docs not necessarily
im)-)ly the absence of the sinus itself, since it may be formed by a retrocession
of the inner wall of the skull. In old persons, as a rule, when the sinuses
' Some portincnt remarks on 11iis fi\il)joct have been made hy Mr. C. IFcatli in a pamphlet
" Od Anatoijiy in relation to Physic."
THE FACE. 915
enlarge, it is by tlie encroacliment of the inner table on the brain-case. The
skull wall here follows the shrinking brain. It is, therefore, important to bear
in mind that an adult, and more especially an elderly person, may have a large
frontal sinus without any external indication of it.
JSTeither does a very prominent bump necessarily imply the existence of a
large sinus, or indeed of even a small one. The "bump" may be a mere heaping
up of bone, a degradation, as in some Australian skulls.
Mastoid Process. — The same observations apply to the air-cells of the
mastoid process, which can be felt behind the ear.
Occipital Protuberance. — The occipital protuberance, the superior curved
line and crest, can be distinctly felt at the back of the head. The protuberance
is always the thickest pd,rt of the skullcap, and more prominent in some than
in others.
The posterior inferior angle of the parietal bone, grooved by the lateral sinuses,
is on a level with the zygoma, and a trifle more than one inch behind the front
border of the mastoid process.
Lines of Cerebral Sinuses. — A line drawn over the head from the root of
the nose to the occipital protuberance corresponds with the superior longitudinal
sinus. Another line drawn from the occipital protuberance to the front border
of the mastoid process corresponds with a part of the lateral sinus.
Middle Meningeal Artery. — The trunk of the middle meningeal artery
runs along the anterior inferior angle of the parietal bone, about one inch and
a half behind, and half an inch above, the external angular process of the
frontal.
A straight line drawn from the front of one mastoid process to the other
would pass through the middle of the condyles of the occiput, showing how
nearly the skull is balanced on the top of the spine in the erect posture.
6. Thickness of Skullcap. — The average thickness of the cap of an adult
skull is about ^ of an inch. The thickest part is at the occipital protuberance,
where it is often | of an inch or more, even in an otherwise thin skull. . The
thinnest part is at the temple, where it may be almost as thin as parchment.
Every one in the habit of making post-mortem examinations knows how
much the skullcap differs in thickness in different persons and in dii&rent
parts of the same skull. In old persons it is often in some parts not thicker
than a shilling, owing to absorption of the diplcie. Another point of interest is
that the inner plane of the cap does not always correspond with the outer.
Hence, in applying the trephine this is not a bad rule — " Think you are opera-
ting on the thinnest skull ever seen, and thinner in one half of the circle than
the other."
7. Levels of the Brain. — The level of the anterior lobes in front corresponds
with a straight line drawn across the forehead, from the narrowest part of the
temporal ridge on each side, easily felt just above the external angular process
of the frontal bone. The lower level of the anterior and middle lobes of the
cerebrum corresponds with a line drawn from the external angular process of
the frontal bone to the upper part of the meatus auditorius. Another line
drawn from the meatus to the occipital protuberance corresponds with the lower
level of the posterior lobe. The lower level of the cerebellum cannot be defined
by external examination. It depends upon the extent to which the occipital
foss£e bulge into the neck ; and this bulge varies in different skulls.
THE FACE.
8. The approaches to the organs of the senses, their ever- varying expression,
their numerous muscles, and their rich profusion of vessels and nerves, give
the face great anatomical importance, which has a most valuable bearing, not
916 LANDMARKS, MEDICAL AND SURGICAL.
only on the practice of surgery, but on the physiognomy of liealth, and in the
diagnosis of disease.
9. Foramina for Branches of 5th Nerve. — As a surgeon may be called
upon to divide either of the three branches of the fifth nerve upon the face, he
looks with interest to the precise situations where they leave their bony foramina
with their corresponding arteries. The supra-orbital notch or foramen can be
felt about the junction of the inner with the middle third of the supra-orbital
margin. From this point a perpendicular line drawn with a slight inclination
outwards, so as to cross the interval between the two bicuspid teeth in both
jaws, passes over the infra-orbital and the mental foramina. The direction of
these two lower foramina looks towards the angle of the nose.
10. Pulley for Superior Oblique Muscle, — By pressing the thumb
beneath the internal angular process of the frontal bone, the cartilaginous
pulley of the superior oblique muscle can be distinctly felt. We should be
careful not to interfere with this pulley in any operation about the orbit.
11. Lower Jaw. — The working of the condyle of the jaw vertically and
from side to side can be distinctly felt in front of the ear. When the mouth is
opened wide, the condyle advances out of the glenoid cavity on to the eminentia
articularis, and returns into its socket when the mouth is shut. The muscle
which causes this advance is the external pterygoid ; and the object of it is to
give the jaw a greater freedom of grinding motion.
The posterior margin of the ramus of the lower jaw corresponds with a line
drawn from the condyle to the angle. In opening abscesses in the parotid region,
the knife should not be introduced behind this line for fear of wounding the
external carotid artery. Punctures to any depth may be safely made in front
of it. They are often necessary where inflammation of the parotid gland ensues
after eruptive fevers, and runs on to suppuration. The swelling, tension, and
pain are most distressing. Owing to the fibrous framework of the gland, the
matter is not circumscribed, but diffused. One puncture is not enough. Three
or more may be requisite. The blade of the knife should be held horizontally,
so as to be less likely to injure the branches of the facial nerve. We are not to
be disappointed if no matter flows. The punctures give relief, and matter will
exude the next day.
12. Parotid Duct. — A line drawn from the bottom of the lobe of the ear
to midway between the nose and the mouth gives the course of the parotid duct.
Opposite the second upper molar, the duct opens by a papilla into the mouth.
The branch of the portio dura which supplies the buccinator runs with the duct.
13. Temporal and Facial Arteries. — The pulsation of the trunk of the
temporal artery can be felt, between the root of the zygoma and the ear. The
facial artery can be distinctly felt as it passes over the body of the jaw at the
anterior edge of the masseter; again near the corner of the mouth close to the
mucous membrane ; and, lastly, by the side of the ala nasi, up to the inner side
of the tendo oculi. By holding the lips between the finger and thumb the coro-
nary arteries are felt under the mucous membrane. The facial vein does not
accompany the tortuous artery, but runs a straight course from the inner angle
of the eye 1o tlic front border of the masseter, just behind the artery.
14. Eyelids and Eyes. — The opening between the eyelids varies in size in
different persons ; hence more of the eyeball is seen in some than in others, and
the eye appears larger. Although human eyes do vary a little in size, yet the
actual difference is by no means so great as is generally supposed. The size of
the fissure has mucli to do with tlio apparent size of the eye. Contrast the
narrow fissure of tlio Cliinese and Mongolian races, and the a])parent smallncss
of their eyes as compared with I^luropeans. As a rule the external angle of the
lid is higher than tlio internal. When not exaggerated, it gives the face an arch
and pleasing expression.
Evert the lids to sec the Meibomian glands; observe tlieir perpendicular
arrangement, in the substance of the tarsal cartilages.
THE FACE. 917
TLie free borders of the lids are not bevelled, as described bj J. L. Petit and
most anatomists, " so as to form with the globe of the closed eye a triangular
canal for the flow of the tears," On the contrary, it is easily seen that the lid
margins, when closed, come into accurate contact. Their plane is not exactly
horizontal, but slightly inclined upwards.
Every time the eye is shut, the ball moves upwards and inwards, so that the
cornea is completely covered by the upper lid. This may be well seen by
raising the lid of a sleeping infant ; also in cases of low fever when the lid is
" not completely closed. This upturning of the eye obviously clears the cornea,
and protects it from the light.
A careful examination of the motion of the lower lid in the act of shutting
the eye proves that it is a double motion. The lid is not only slightly raised,
but drawn inwards about -^^ of an inch. This second movement sweeps any
particles of dust as well as moisture towards the inner canthus.
15. Puncta Lacrymalia. — The puncta lacrymalia are distinctly visible
at the inner angles of the lids. The lower punctum is larger and a little more
external than the upper, so that they are not exactly opposite. The direction,
too, of the puncta deserves notice. Their open mouths look a little backwards,
ready to imbibe the tears. When their proper bearing is lost, as in facial
paralysis or a cicatrix near the lid, the tears overflow the cheek. The length
of the lachrymal canals is from three to four lines. The lower is a little shorter
and wider than the upper. As they both make a little angle in their course,
soon after their orifices, the lids should be drawn outwards to straighten them
when we introduce a probe.
16. Lachrymal Sac. — To find the lachrymal sac, draw^ outwards the eyelids
to tighten the tendo oculi, which crosses the sac a little above its middle. A
knife introduced just below the tendon close to the edge of the orbit would enter
the sac. The angular artery and vein would be on the inner side of the incision.
A probe directed in a line with the inner edge of the orbit, i. e. downwards,
outwards, and backwards, would traverse the nasal duct, and appear in the
inferior meatus of the nose.
The tendo oculi serves many purposes besides giving attachment to the carti-
lages and muscles of the lids. One purpose is said to be to pump the tears into
the lachrymal sac. Place a finger on the tendon, and feel that it tightens every
time the lids are closed. The tendon, being intimately connected to the sac,
draws, as it tightens, the sac wall outwards and forwards, and in this way it
may pump along the lachrymal canals any fluid collected at the angle of the eye.
17. Nasal Buct. — The nasal duct is from six to eight lines long, and nar-
rowest in the middle of its course. Its termination in the inferior meatus lies
under the inferior spongy bone, about a quarter of an inch behind the bony edge
of the nostril. The appearance of the orifice in the dry bone conveys no idea
of its size and shape in life ; for it is diminished by a valve-like fold of mucous
membrane, so that it becomes, in most cases, a mere slit, not exceeding a line
in diameter.
The facility with which instruments can be introduced into the nasal opening
of the duct depends upon its position as well as its size. This position varies in
different instances. Sometimes it opens directly into the roof of the inferior
meatus, in which case the hole is large and round, so that tears readily run into
the nose. In other instances the opening is situated on the outer wall of the
meatus, and is then always such a narrow fissure as to be hardly discernible.
The practical conclusion then is, that a probe can be easily introduced when
the opening is in the roof of the meatus, but not without difficulty and lacera-
tion of the mucous membrane when on the outer wall. This difficulty indeed
may be increased by the narrowness of the meatus, arising from an unusual
curvature of the spongy bone.
18. Nose and Nasal Cavities. — The line where the cartilages of the nose
are attached to the nasal and superior maxillary bones can be traced with pre-
918 LANDMARKS, MEDICAL AND SURGICAL.
cision. The close connection of the skm to the cartilages admits of no stretching ;
hence the acute pain felt in erysipelas and boils on the nose. The external
aperture of the nose is always placed a little lower than the floor of the nostril,
so that the nose must be pulled up before we can inspect its cavities.
Looking into the nostrils, we rind that the left is, in the majority of cases,
narrower than the right, owing to an inclination of the septum towards the left.
A communication sometimes exists between them, through a hole in the septu.m,
as was the case in the celebrated anatomist Hildebrandt, By dilating the alas
nasi, we can get a view of the end of the inferior spongy bone. The middle
spongy bone cannot be seen : its attachment to the ethmoid is high up, nearly
opposite the tendo oculi. The cavities are so much narrowed transversely by
the spongy bones, that in the extraction of polypi it is better to dilate the blades
of the forceps perpendicularly, and near the septum.
19. Mouth. — What can be seen and felt through the mouth? The upper
surface of the tongue, '■'■ speculuon primarum viaruTn,''' is a study in itself. We
notice, on its under surface, a median furrow, on each side of which stands out
the ranine vein, lying upon the prominent fibres of the lingualis. On the floor
of the mouth is the "frenum linguse," in the middle line, with the orifices of
the ducts of the submaxillary glands on each side of it. The glands themselves
can be felt immediately beneath the mucous membrane.
We can feel the attachment of the "genio-hyo-glossi" behind the symphysis
of the jaw. The division of this attachment would enable a surgeon to draw
the tongue more freely out of the mouth in any attempt to remove carcinoma
extending far back into its root.
There is great diiJ'erence in the shape of the hard palate: this difference
depends upon the depth of the alveolar processes. In some it forms a broad
arch ; in others it is narrow, and rises almost to a point like a Gothic arch, and
materially impairs the tone of the voice.
Throat. — To examine the throat well, the nose should be held so as to com-
pel breathing through the mouth. Thus the soft palate will be raised, the
palatine arches widened, and the tonsils and the back of the pharjaix fairly
exposed. Pressing the tongue downwards, provided it be done very gently, is
also of advantage. Eude treatment the tongue would resist. The forefinger
can be passed into the throat as low as the bottom of the cricoid cartilage, and
thus search the pharynx down to the top of the oesophagus, and the hyoid space
(on each side) where foreign bodies are so apt to lodge. In introducing a stom-
ach pump, the finger should keep the instrument well against the back of the
pharynx so as to prevent its slipping into the larynx.
Put the finger into the mouth, and feel the anterior border of the coronoid
process of the jaw. On the inner side of this process, between it and the tube-
rosity of the upper jaw, is a recess, where a deeply-seated temporal abscess
might burst, or might be opened. Behind the last molar tooth of the upper
jaw we can distinctly feel the hamular process of the sphenoid bono ; also the
lower part of the pterygoid fossa, and the internal pterygoid plate. Behind,
and on the outer side of the last molar, can be felt part of the back of the antrum
and of the lower part of the external pterygoid plate.
On the roof of the mouth we can feel the pulsation of the posterior ])al;itiiic
artery. Ilcmorrliagc from this vessel can be arrested by plugging the (jrifice of
the canal, which lies (not fiir from the surface) on the inner side of the last
molar, about ^ of an inch in front of the hamular process,
. When the mouth is wide open, the pterygo-maxillary ligament forms a prom-
inent fold readily seen and felt beneath tJie mucous membrane, behind the last
molar teeth. A little below the attachment of this ligament to the lower jaw
we can easily feel the gustatory nerve, as it runs close to the bone below the
last molar tooth. The exact position of the. nerve can be ascertained in one's
own person by the acute pain on prcssujc. A division of the nerve, easily
THE FACE. 919
effected by a small incision in the right place, gives much temporary relief in
cases of advanced carcinoma of the tongue.
To feed a patient in spasmodic closure of the jaAv, it is well to know that
there exists behind the last molar teeth a space sufficient for the passage of a
small tube.
Antrum. — Lift up the upper lip and examine the front wall of the antrum.
The proper place in which to tap it is above the second bicuspid tooth, about
one inch above the margin of the gum.
20. Posterior Nares. — A surgeon's finger should be familiar with the feel
of the .posterior nares, and of all that is within reach behind the soft palate.
This is important in relation to the attachment of polypi, to plugging the nos-
trils, and the proper size of the plug. In the examination of this part of the
back of the throat it is necessary to throw the head well back, because, in this
position, nearly all the pharynx in front of the basilar process comes down below
the level of the hard palate, and can be seen as well as felt. But when the
skull is horizontal, i. e., at a right angle with the spine, the hard palate is on a
level with the margin of the foramen magnum, and the parts covering the ba-
silar process are concealed from view.
The head, then, being well back, introduce the forefinger behind the soft
palate, and turn it up towards the base of the skull. You feel the strong grip
of the superior constrictor. Hooking the finger well forwards, you can feel the
contour of the posterior nares. Their size depends upon the anterior, but rarely
exceeds a small inch in the long diameter, and a small half-inch in the short.
The plug for the posterior nares should not be larger than this. Their plane is
not perpendicular, but slopes a little forwards. You can feel the septum formed
by the vomer, and also the posterior end of the inferior spongy bone in each
nostril.
21. Tonsils. — Before taking leave of the throat, look well at the position of
the tonsils between the anterior and posterior half arches of the palate. In a
healthy state they should not project beyond the level of these arches. In all
operations upon the tonsils, we should remember the close proximity of the
internal carotid artery to their outer side. Nothing intervenes but the pharyn-
geal aponeurosis, and the superior constrictor of the pharynx. Hence the rule
in operating on the tonsils always to keep the point of the knife inwards.
In troublesome hemorrhage from the tonsils, after an incision or removal, it
is well to know that they are accessible to pressure if necessary by means of a
padded stick, or even a finger.
22. Features. — A word or two on the lines of the face as indicative of ex-
pression. Every one pays unconscious homage to the study of physiognomy,
when, scanning the features of a stranger, he draws conclusions concerning his
intelligence, disposition, and character. Without discussing how much physiog-
nomy is really worth, there can be no doubt that it is a mistake to place it in
the same category as phrenology, since the latter lacks that sound basis of
physiology which no one can deny to the former.
The muscles of the features are generally described as arising from the bony
fabric of the face, and as inserted into the nose, corners of the mouth, and the
lips. But this gives a very inadequate idea of their true insertion. They drop
fibres into the skin all along their course, so that there is hardly a point of the
face which has not its little fibre to move it. The habitual recurrence of good
or evil thoughts, the indulgence in particular modes of life, call into play corre-
sponding sets of muscles which, by producing folds and wrinkles, give a perma-
nent cast to the features, and speak a language which all can understand, and
rarely misleads. Schiller puts this well when he says that "it is an admirable
proof of infinite wisdom that what is noble and benevolent beautifies the human
countenance ; what is base and hateful imprints upon it a revolting expression."
920 LANDMARKS, MEDICAL AND SURGICAL,
THE NECK.
23. Subcutaneous Veins. — Notice first the direction of the subcutaneous
veins. The cliief subcutaneous vein is the external jugular. Its course corre-
sponds with a line drawn from the angle of the jaw to the middle of the clavicle,
where it joins the subclavian. It is made more prominent by putting the
sterno-mastoid into action, or gentle pressure on the lower end of the vein. It
is exceptionally joined by a branch which runs over the clavicle, and is termed
"jugulo-cephalic." The anterior jugular generally runs along the front border
of the sterno-mastoid.
24. Parts in Central Line. Os-hyoides.— -Immediately below and nearly
on a level with the lower jaw we feel the body of the os-hyoides, and can trace
backwards on each side the whole length of the cornua. They might easily be
broken by the grasp of a garotter. Below the body of the os-hyoides is the
gap above the thyroid cartilage. This gap corresponds with the anteriorly
thyro-hyoid ligament and the apex of the epiglottis: so that in cases of cut
throat in this situation, nearly the whole of the epiglottis lies above the wound.
Thyroid Cartilage. — The projection and depth of the notch in the thyroid
cartilage, or "pomuni Adami," varies in different persons. Between the notch
and the hyoid bone there is a large bursa, to facilitate the play of the cartilage
beneath the bone in deglutition. The notch does not appear till puberty, and
is, throughout life, much less distinct in the female than the male. The finger
can trace the upper borders and cornua of the thyroid cartilage: its lower
cornua can be felt by the side of the cricoid.
On each side of the thyroid cartilage we can recognize the lateral lobes of the
thyroid gland. On the upper and front part of the gland we can distinctly feel
the pulsation of the superior thyroid artery. This pulsation, coupled with the
fact that the gland rises and falls with the larynx in deglutition, is the best
distinction between a bronchocele and other tumors resembling it.
Below the angle of the thyroid cartilage we feel the interval between it and
the cricoid, which is occupied by the crico-thyroid membrane. In laryngotoni}^
we cut through this membrane transversely close to the upper edge of the cri-
coid cartilage, in order that the incision may be as far as possible from the
attachment of the vocal cords.
26. Cricoid Cartilage. — The projection of the cricoid cartilage is a point of
great interest to the surgeon, because it is his chief guide in opening the air-
passages, and can always be felt even in infants, however young or fat. It
corresponds to the interval between the fifth and sixth cervical vertebree. The
commencement of the oesophagus lies behind it: here, therefore, a foreign sub-
stance too large to be swallowed would probably lodge, and might be felt ex-
ternally.
Again, a transverse line drawn from the cricoid cartilage horizontally across
the neck would pass over the spot where the omo-hyoid crosses the common
carotid. Just above this spot is the most convenient place for tying the artery.
26. Those who have not directed their attention to the subject are hardly
aware what a little dislancc there is between the cricoid cartilage and the upper
pint of the sternum. In a person of the average height sitting with the neck
in an easy position, the distance is barely one inch and a half. When the neck
is well stretched, about three-quarters of an inch more is gained. Thus, we
have (generally) not more than seven or eight rings of the tracliea above the
sternum. None of those rings can be felt externally. The second, third, and
foiirlh are covered by the isthmus of the thyroid gland. The tracliea, it should
be remembered, recedes from the surface more and more as it descends, so tliat,
just above the sternuni in a short, fat-necked adiill, the front of the trachea
would be quite one inch and a half from ihe skin.
THE NECK. 921
27. Trachea. — In the dead subject nothing is more easy than to open the
trachea : in tlie living, no operation may be attended with greater difficulties.
In urgent dyspnoea you must expect to find the patient with his head bent for-
wards, and the chin dropped, to relax as much as possible the parts. On raising
his head, a paroxysm of dyspnoea is almost sure to come on, threatening instant
suffocation. The elevator and depressor muscles draw the trachea and larynx
up and down with a rapidity and a force which may bring the cricoid cartilage
within half an inch of the sternum. The great thyroid veins .which descend in
front of the trachea are sure to be distended. There may be a middle thyroid
artery. In children the lobes of the thymus may extend up in front of the
trachea, and the left vena innominata may cross it unusually high. Thus the
air-tube may be covered by important parts which ought not to be cut. Con-
sidering all these possible complications, the least difficult and the best mode of
proceeding is to open the trachea just below the cricoid cartilage ; and if more
room be requisite, to pull down the isthmus of the thyroid gland, or (in children)
divide the cricoid itself. It is important that all the incisions be made strictly
in the middle line, the " line of safety."
28. Sterno-mastoid Muscle. — The sterno-mastoid muscle is the great surgi-
cal landmark of the neck. It stands out in bold relief when the head turns
towards the opposite shoulder. Its inner border overlaps the common carotid,
which can be easily compressed for a short time against the spine about the
level of the cricoid cartilage. The artery extends (generally) as high as the
upper border of the thyroid cartilage, and corresponds with a line drawn from
the sterno-clavicular joint to midway between the angle of the jaw and the
mastoid process.
Between the sternal origins of the sterno-mastoid is the fossa above the ster-
num, more or less perceptible in different necks. As it heaves and sinks alter-
nately, especially in distressed breathing, it was called by the old anatomists
" fonticLilus gutturis." In beautiful necks, as seen in the " Venus," it is filled
up by fat.
Notice the interval between the sternal and clavicular origins of the sterno-
mastoid. A knife introduced a very little way into this interval would wound,
slanting inwards, the common carotid, slanting outwards, the internal jugular
vein. These facts are of importance in performing the subcutaneous section of
the tendon of this muscle.
29. Sterno-clavicular Joint. — Many important parts lie behind the sterno-
clavicular joint. There is the commencement of the vena innominata; behind
this comes the division of the arteria innominata on the right side, and the
common carotid on the left. Deeper still, the apex of the lung rises into the
neck.
In a child the arteria innominata often lies in front of the trachea and divides
a little higher than the joint : a point to be remembered in tracheotomy (27).
80. Apex of Lung in the Neck.- — The extent to which the apex of the
lung rises into the neck is greater than is generally supposed. Many observa-
tions in reference to this point lead to the conclusion that the lung rises behind
the sterno-mastoid, on an average, one inch and a half above the clavicle ; in
persons with long necks, as much as two inches. The apex of the lung and
pleura is covered by the clavicular origin of the sterno-mastoid, the sterno-
thyroid, and a part of the scalenus anticus. It is also crossed by the subclavian
vessels in the first part of their course. As this cervical portion of lung is
peculiarly liable to tubercular disease, it should always be carefally examined.
Its condition may be ascertained by percussion on the clavicle.
31. Supraclavicular Fossa. — The hollow above the clavicle, between the
sterno-mastoid and the trapezius, is very manifest in emaciation and old age.
Notice the termination here of the external jugular vein. In some necks only
a small depression is visible, particularly when the trapezius has a broad inser-
922 LANDMARKS, MEDICAL AND SURGICAL.
tion into tlae clavicle, and comes well forwards, so that its front border gives a
graceful contour to the base of the neck.
32. Subclavian Artery. — In the supra-clavicular fossa, near the outer
border of the sterno-mastoid, and about one inch above the clavicle, we feel the
pulsation of the subclavian artery. Here the artery lies upon the first rib, and
can be effectually compressed. A little pressure is sufficient. But the pressure
must be made in the right direction, or the artery will be pressed off the rib
instead of against it. The plane of the rib is such, that the pressure, to be
effectual, must be made in a direction downwards and a little inwards. It is
best to stand behind the shoulder and make the pressure with the thumb.
It is worth remembering that the outer border of the sterno-mastoid corre-
sponds pretty nearly with the outer edge of the scalenus anticus, which is the
surgical guide to the subclavian artery.
By pressing deeply at the upper part of the supra- clavicular fossa, the trans-
verse process of the seventh cervical vertebra can be distinctly felt.
In long and thiii necks, a thin cord is perceptible, running nearly parallel
with and just above the clavicle. It is the posterior belly of the omo-hyoideus.
See it rising and falling in breathing, and making tense during inspiration that
part of the cervical fascia which lies over the cervical portion of the lung. Thus
it may be said to be in all respects a muscle of inspiration, co-operating with
the sterno-mastoid and scaleni. In the language of transcendental anatomy, we
may say that the central tendon of the omo-hyoid represents a rudimentary
cervical rib. Its posterior belly is analogous to a serration of the serratus mag-
nus; its anterior belly to a sterno-hyoid.
THE CHEST.
33. As a rule, the right half of the chest is slightly larger than the left. Of
ninety-two persons of the male sex and good constitutions, seventy-one had the
right side the larger; eleven the left; ten had both sides equal. The maximum
of difference in favor of the right was 1\ inch. The measurements were made
on a plane with the nipple.
34. Peculiarities in the Female. — The chest of the female differs from
that of the male in the following points : — Its general capacity is less ; the
sternum is shorter ; the upper opening is larger in proportion to the lower ; the
"upper ribs are more movable, and therefore permit a greater enlargement of the
chest at its upper part, in adaptation to the requirements of pregnancy.
35. The top of the sternum is on a level witli the second dorsal vertebra;
and the available space between the top of the sternum and the spine is hardly
more than two inches.^
36. Parts behind first Bone of Sternum — There is little or no lung behind
the first bone of the sternum, the S})ace being occupied by the trachea and large
vessel as follows: —
The left vena innominata crosses the sternum just below the upper border.
Next come the great j)rimary branches of the arch of the aorta. Deeper still is
the trachea dividing intO'its two bronchi opposite the junction of the first and^
second bones of the sternum. Deepest of all is the oesophagus.
About one inch from the upper border of the sternum is the highest part of
the arch of the aorta, which lies on the bifurcation of the trachea.
37. The course of the arteria innominata corresponds with a line drawn from
the middle! of tlie jiinctif)n of the first witli the second bone of the sternum, to
' In fiovfral mliilt norriKil Kkolotons monsnrod in llic TImitoriun Mnsoiim, tlio avornfi'o dinmotors
of the upper npcniiip- of llic flicst wcro— nnlcro-postcrior, iilxxit 2\ inclics; Iransvcrsc, ivboiit A^
inclioa. In llio Hlvcloldn of O'iirien, the Irish giant, the aiitero-posterior diameter measures 4
inches, the transverse 6^.
THE CHEST. 923
tile right sterno-clavicular joint. When the artery rises higher than usual into
the neck, its pulsation can be felt in the fossa above the sternum.
38. Rules for Counting the Ribs. — In fat persons it is often difficult to
count the ribs; hence the following rules may be useful: —
a. The finger passed down from the top of the sternum soon comes to a trans-
verse projection, slight, but always to be felt, at the junction of the first with
the second bone of the sternum. This corresponds with the level of the cartilage
of the second rib.
h. The nipple in the male is placed, in the great majority of cases, between
the fourth and the fifth ribs, about three-quarters of an inch external to their
cartilages.
c. The lower external border of the pectoralis major corresponds with the
direction of the fifth rib.
d. A line drawn horizontally from the nipple round the chest cuts the sixth
intercostal space midway between the sternum and the spine. This is a useful
rule in tapping the chest.
e. When the arm is raised, the first visible digitation of the serratus magnus
corresponds with the sixth rib. The digitations below this correspond respec-
tively with the seventh, eighth, and ninth ribs.
/. The scapula covers the ribs from the second to the seventh, inclusive.
g. The eleventh and twelfth ribs can be felt even in corpulent persons, outside
the erector spinas, sloping downwards.
h. One should remember the fact that the sternal end of each rib lies on a
lower level than its corresponding vertebra. For instance, a line drawn hori-
zontally backwards from the middle of the third rib at its junction with the
sternum, to the spine, would touch the body, not of the third dorsal vertebra,
but of the sixth. Again, the end of the sternum would be about the level of
the tenth dorsal vertebra.
89. Interval below Clavicle. — Immediately below the clavicle we recog-
nize the triangular interval between the pectoralis major and the deltoid. This
space varies in different cases, depending on the distance between the muscles.
It is important as a guide to the coracoid process and the axillary artery. In a
case of injury to the shoulder, to ascertain whether the coracoid process is
broken, carry the arm outwards, to pat the deltoid and pectoral muscles on the
stretch, and make manifest the space between their opposite borders. Pressing
the thumb into the space we can feel the inner side of the coracoid process, the
apex being under the fibres of the deltoid ; thus it is easy to ascertain whether
it be broken. Moreover, this space corresponds with the line of the axillary
artery ; here its pulsation can be distinctly felt, and here it can be compressed
(but not easily, or for long) against the second rib.
40. Internal Mammary Artery. — The line of the internal mammary artery
runs perpendicularly behind the cartilages of the ribs, about half an inch from
.the sternum. The perforating branch through the second intercostal space is
generally the largest.
41. Outline of Heart on Chest- wall. — To have a general idea of the form
and position of the heart, map its outline on the wall of the chest, as follows : —
a. To define the base draw a transverse line across the sternum corresponding
with the upper borders of the third costal cartilages : continue the line half an
inch to the right of the sternum and one inch to the left.
h. To find the apex, mark a point about two inches below the left nipple, and
one inch to its sternal side. This point will be between the fifth and sixth ribs.
c. To find the lower border (which lies on the central tendon of the dia-
phragm), draw a line, slightly curved downwards, from the apex across the
bottom of the sternum (not the ensiform cartilage) as far as its right edge.
d. To define the right border (formed by the right auricle), continue the last
line upwards with an outward curve, so as to join the right end of the base.
e. To define the left border (formed by the left ventricle), draw a line curving
924
LANDMARKS, MEDICAL AND SURGICAL.
to the left, but not including the nipple, from the left end of the base to the
apex.
Such an outline (seen in the cut, with the angles rounded off') shows that the
apex of the heart points downwards and towards the left, the base a little up-
wards and towards the right ; that the greater part of it lies in the left half of
FjV. 521.
Outline of the Heart, its Valves, and the Lungs.
the chest, and that the only part which lies to the right of the sternum is the
right auricle. A needle introduced in the third, the fourth, or the fifth right
intercostal space close to the sternum would penetrate the lung and the right
auricle.
A needle passed through the second intercostal space, close to the right side
of the sternum, would, after passing through the lung, enter the pericardium
and the most prominent part of the bulge of the aorta.
A needle passed through the first intercostal space, close to the right side of
the sternum, would pass through the lung and enter the superior vena cava
above the pericardium.
42. The best definition of that part of the prascordial region, which is less
resonant on percussion, was given by Dr. Latham years ago in his " Clinical
Lectures." " Make a circle of two inches in dianielcr round a point midway
between the nipple and the end of the sternum. This circle will define, suifi-
ciently for all practical purposes, that part of the heart which lies immediately
b(;liind llic Willi of iIk; chest, and is not covered by lung or pleura."
Apex of the Heart. — The apex of the heart pulsates between the fifth and
sixth ribs, two inches below the nipple, and one inch to its sternal side. The
place and extent, however, of the heart's impulse, vary a little with the position
of the body. Of this any one may conviuci! himself i3y leaning forwards, back-
wards, on this aide and on that, feeling, at tlic same time, the heart. Inspira-
tion and expiration also alter the position of the heart. In a deep insy)iration
it may descend half an inch, and can be felt bcaling at the pit of the stomach.
THE CHEST. 925
4:3. Valves of the Heart. — The aortic valves lie beliind the third inter-
costal space, close to the left side of the sternum.
The pulmonary valves lie in front of the aortic behind the junction of the
third rib, on the left side, with the sternum.
The tricuspid valves lie behind the middle of the sternum, about the level
of the fourth costal cartilage.
The mitral valves (the deepest of all) lie behind the third intercostal space,
about one inch to the left of the sternum.
Thus these valves are so situated that the mouth of an ordinary sized stetho-
scope will cover a portion of them all, if placed over the junction of the third
intercostal space, on the left side, with the sternum. All are covered by a thin
layer of lung ; therefore we hear their action better when the breathing if for a
moment suspended,
44. Outline of the Lungs. — Now let us trace on the chest the outline of
the lungs, with as much precision as their expansion and contraction in breath-
ing permit. (See Fig. 521.)
45. The apex of each lung rises into the neck behind the sternal end of the
clavicle and sterno-mastoid muscle as much as IJ inch, in females rather higher
than in males (30). From the sternal ends of the clavicles the lungs converge,
so that their thin edges almost meet in the mesial line on a level with the
second costal cartilage. Thus there is little or no lung behind the first bone of
the sternum. From the level of the second costal cartilage to the level of the
fourth, the margins of the lungs run parallel, or nearly so, close behind the
middle of the sternum : consequently their thin edges overlap the great vessels
and valves at the base of the heart.
Below the level of the fourth costal cartilage the margins of the lungs diverge,
but not in an equal degree. The margin of the right corresponds with the
direction of the cartilage of the sixth rib: the margin of the left, being notched
for the heart, runs behind the cartilage of the fourth. A line drawn perpen-
dicularly from the nipple would find the lung margin about the lowest part of
the sixth rib. Laterally, i. e. in the axillary line, the lung margin comes down
as low as the eighth rib: posteriorly, i. e. in the dorsal or scapular line, it de-
scends as low as the tenth.
It should be remembered that, in a deep inspiration, the lung margins descend
about 1|- inch.
In children the lungs are separated in front by the thymus gland. Allowance
should be made for this. About the approach of puberty the thymus dis-
appears.
46. Anterior Mediastinum, — The direction of the anterior mediastinum
is not straight down the middle of the sternum, but slants a little to the left,
owing to the position of the heart. The right pleural sac generally encroaches
a little upon the left, behind the middle of the sternum. A needle introduced
through the middle of the sternum opposite the third or the fourth rib would go
through the right pleura.
47. Reflection of Pleura. — The reflection of the pleura from the wall of
the chest on to the diaphragm corresponds with a sloping line drawn from the
bottom of the sternum over the cartilages of the ribs down to the lower border^
of the last rib.
Since the pleura lines the inside of the last rib, a musket ball or other foreign
body, loose in the pleural sac, and rolling on the diaphragm, might fall to the
lowest part of the sac, which would be between the eleventh and twelfth ribs.
The ball might be extracted here. The chest might also be tapped here, but
not with a trocar, since a trocar would penetrate both layers of pleura, and go
through the diaphragm into the abdomen.
The operation should be done cautiously, by an incision beginning about two
inches from the spine, on the outer border of the "erector spin«," on a level
926 LANDMARKS, MEDICAL AND SURGICAL.
between the spines of the eleventh and twelfth dorsal vertebra. The intercostal
artery will not be injured if the opening be made below the middle of the space,
which is very wide.^
THE BACK.
48. Median Furrow. — In a muscular man, a furrow, caused by the prom-
"inence of the erector spinte on each side, runs down the middle of the back.
The bottom of the furrow corresponds with the interval between the spine of
the last lumbar and that of the first sacral vertebra.
49. Spines of Vertebrae. — ^A little friction with the fingers down the back-
bone will cause the spines of the vertebrse to be tipped with red, so that they
can be easily counted and any deviation from the straight line detected. Still
it is worth remembering that the spine of the third dorsal is on a level with the
commencement of the spine of the scapula — that the spine of the seventh dorsal
is on a level with the inferior angle of the scapula — that the spine of the last
dorsal is on a level with the head of the last rib.
Division of the Trachea. — The division of the trachea is opposite the
spine of the third, in some cases the fourth, dorsal vertebra. In front this divi-
sion is on the level of the junction of the first with the second bone of the ster-
num.
The root of the spine of the scapula is marked by a slight dimple in the skin.
This is on a level with the third intercostal space. A stethoscope placed on the
inner side of this dimple would cover the bronchus, more especially the right,
since it is nearer to the chest wall.
50. The place where the kidney is most accessible to pressure is below the
last rib, on the outer edge of the erector spinas.
51. The highest part of the ilium is about the level of the fourth lumbar spine.
The best incision for opening the descending colon is in a slightly sloping line
beginning at the outer edge of the erector spinse, midway between the crest of
the ilium and the last rib, and continued across the flank for three inches or
more, according to the amount of subcutaneous fat.
52. In the pit of the neck we can feel the trapezius and the ligamentura
nucha3. By pressing deeply we detect the forked and prominent spine of tlie
second cervical vertebra.
53. The spines of the third, fourth, and fifth cervical vertebras recede from
the surface to permit free extension of the neck, and cannot often be felt. But
the spines of the sixth and seventh (v. prominens) stand out well.
54. Notice that most of the spines of the dorsal vertebrae, owing to their obli-
quity, do not tally with the heads of their corresponding ribs. Thus, the spine
of the second dorsal corresponds with the head of the third rib ; the spine of
the third dorsal with the head of the fourth rib, and so on till we come to the
eleventh and twelfth dorsal vertebrae, which do tally with their corresponding
ribs. All this, however, is best seen in the skeleton,
55. The spines of the vertebrae may be useful as landmarks indicative of the
levels of important organs; I have therefore arranged them in a tabular form,
thus: —
' Spofiiil oxpprimcnts upon this subject were made ituiiiy j'Pnvs ago, by llie late Profossor
Qucki'tl in the work rooms of the College of Surgeons.
THE BACK. 927
Tabular Plan of Parts opposite the Spines of the Vertebra.
^ 4 7th. Apex of lung : higher in the female than in the male. (30)
I— I
<^
O
pq J
D
1st.
2d.
3d. Aorta reaches spine. Apex of lower lobe of lung. Angle of bifur-
cation of trachea. (49)
4th. Aortic arch ends. Upper level of heart.
5th.
6th.
^ 7th.
8th. Lower level of heart. Central tendon of diaphragm.
9th. CEsophagus and vena cava through diaphragm. Upper edge of
spleen.
10th. Lower edge of lung. Liver comes to surface posteriorly. Cardiac
orifice of stomach.
11th. Lower border of spleen. Eenal capsule.
12th. Lowest part of pleura. Aorta through diajDhragm. Pylorus.
1st. Renal arteries. Pelvis of kidney. (83)
2d. Termination of spinal cord. Pancreas. Duodenum just below. Re-
ceptaculum chyli.
3d. Umbilicus. Lower border of kidney.
4th. Division of aorta. (65) Highest part of ilium.
5th.
56. Origins of the Spinal Nerves. ^ — It is useful to know opposite what
vertebrae the spinal nerves in the dili'crent regions arise from the spinal cord.
They arise as follows : — ■
The origins of the eighth cervical nerves correspond to the interval between
the occiput and the sixth cervical spine.
The origins of the first six dorsal nerves correspond to the interval between
the sixth cervical and the fourth dorsal spines.
The origins of the six lower dorsal nerves correspond to the interval between
the fourth and the eleventh dorsal spines.
The origins of the five lumbar nerves correspond to the interval between the
eleventh and twelfth dorsal spines.
The origins of the five sacral nerves correspond to the spine of the last dorsal
and the first lumbar vertebrae.
57. Movements of the Spine. — The movements of which the spine is
capable are threefold : 1, Flexion and extension ; 2, lateral inclination ; 3, torsion.
Flexion and extension are freest between the third and the sixth cervical verte-
brge, brtween the eleventh dorsal and the second lumbar, and between the last
lumbar and the sacrum. This is well marked in severe cases of opisthotonos,
where the body is supported on the back of the head and heels. Of this there
is a beautiful illustration (see Fig. 522) in Sir C. Bell's "Anatomy of Expres-
sion," p. 160.
Still better may it be observed when a mountebank bends backwards, and
touches the ground with his head.
The lateral movement is freest in the neck and the loins.
The movement of torsion or rotation round its own axis may be proved by
the following experiment : Seated upright, with the back and shoulders well
applied against the back of a chair, we can turn the head and neck as far as
70°. Leaning forwards so as to let the dorsal and lumbar vertebrae come into
play, we can turn 30° more.
928
LANDMARKS, MEDICAL AND SURGICAL.
Opisthotonos. (After Bell.)
58. Position and Motions of Scapula.— There are a few points worthy
of observation about the scapula. It covers the ribs from the second to the
seventh inclusive. We can feel its superior angle covered by the trapezius.
The inferior angle is covered by the latissimus dorsi, which keeps it well applied
against the ribs in the strong and athletic ; but in weak and consumptive persons
the lower angles of the scapuliB project like wings — hence the terms "scapulge
alatffi."
A line drawn horizontally from the spine of the sixth dorsal vertebra over
the inferior angle of the scapula gives the npper border of the latissimus dorsi.
Another line drawn from the root of the spine of the scapula to the spine of the
last dorsal vertebra gives the lower border of the trapezius, which stands a
little in relief.
59. The sliding movement of the scapula on the chest can be properly under-
stood only on the living subject. It can move not only upwards and downwards
as in shrugging the shoulders — backwards and forwards as in throwing back
the shoulders^ — -but it has a rotatory movement round a movable centre. This
rotation is seen while the arm is being raised from the horizontal to the vertical
position, and is effected by the co-operation of the trapezius with the serratus
magnus. The glenoid cavity is thus made to look upwards, the inferior angle
slides forwards, and is well held under the latissimus dorsi.
60. For the medical examination of the back, the patient should sit with the
arms hanging between his thighs, to lower the scapulas as much as possible. In
this position the spine of the scapula corresponds (nearly) with the fissure be-
tween the upper and lower lobes of the lung ; the apex of the lower lobe being
about the level of the third rib.
TTIE ABDOMEN.
The student is assnn 10(1 lo be familiar wilh the arbitrary lines dividing the
abdomen iii1o regions.
61. Abdominal Lines.-- The linca alba, or ccMilral line of the abdomen,
marks the union of the a])oneiiroscs of the abdominal muscles. It runs from
the apex of the cnsiform cartilage to the symphysis i)ubis. As this line is the
thinnest and least vascular part of lhc abdominal \v;ill, we make onr incision
along it in ovariotomy, and in the high operation of lithotomy ; in it, we tap
the abdomen in ascites, and the distended bladder in retention of urine.
The so-called "linea scMnilunaris," where the a])()nenroscs of the abdominal
muscles divide to form lhc sheath of the rectus, corresponds with a line, drawn
THE ABDOMEN. 929
slightly curved (with the concavity towards the linea alba), from the lowest
part of the seventh rib to the spine of the pubes. This line would be in an
adult about three inches from the umbilicus ; but in an abdomen distended by
dropsy or other cause, the distance is increased in proportion.
It is important to know the position of the " linese transversse," or tendinous
intersections across the rectus abdominis. There are rarely any below the
umbilicus, and generally three above it. The first is about the level of the
umbilicus. The second is about four inches higher — that is, about the level of
the lowest part of the tenth rib. These are the principal lines, and they divide
the upper part of each rectus into two nearly quadrilateral portions, an upper
and a lower : of these, those on the right side are a trifle larger than on the
left. We see these muscular squares pretty plainly in some athletic subjects.
Much more frequently we see them, too much exaggerated, on canvas and in
marble. Artists are apt to exaggerate them, and make the front of the belly
too much like a chess-board. It is lucky for them that all the world do not see
with anatomical eyes.
A familiarity with the shape and position of these divisions of the rectus is
of importance, lest we should, in ignorance, make a mistake in our diagnosis.
A spasmodic contraction of one of these divisions, particularly the upper, or a
collection of matter within its sheath, has been frequently mistaken for deep-
seated abdominal disease.
In the erect position, the anterior superior spines of the ilia are a little below
the level of the promontory of the sacrum. The bifurcation of the aorta is
about the level of the highest part of the crest of the ilium.
62. Umbilicus. — The umbilicus is not midway between the ensiform carti-
lage and the pubes, but rather nearer to the pubes. In all cases it is situated
above the centre of a man's height. It is a vulgar error to say that when a
man lies with legs and arms outstretched, and a circle is drawn round him, the
umbilicus lies in the centre of it. This central point is in most persons just
above the pubes.
In very corpulent persons two deep transverse furrows run across the abdo-
men. One runs across the navel and completely conceals it. The other is lower
down, just above the fat of the pubes. In tapping the bladder above the pubes
in such a case, the trocar should be introduced where this line intersects the
linea alba.
Although the position of the umbilicus varies a little in different persons, as
the abdomen is unusually protuberant or the reverse, still, as a general rule, it
is placed about the level of the body of the third lumbar vertebra. Now, since
the aorta divides a little below the middle of the fourth lumbar, it follows that
the best place to apply pressure on this great vessel is one inch below the
umbilicus, and slightly to the left of it (65). That the aorta can, under favorable
circumstances, be compressed under chloroform sufficiently to cure an aneurism
below it, is proved by recorded cases, and by none more effectually than by a
case related in the second volume of the " Eeports of St. Bartholomew's Hospital."
It may be asked, why not apply pressure on the aorta above the umbilicus ?
The answer is, that the aorta above the umbilicus is further from the surface,
and is, moreover, covered by important structures upon which pressure would
be dangerous.
63. Parts behind Linea Alba. — Let us next consider what viscera lie
immediately behind the linea alba. For two or three fingers' breadth below
the ensiform cartilage there is the left lobe of the liver, which here crosses the
middle line. Below the edge of the liver comes the stomach, more or less in
contact with the linea alba, according to its degree of distension. In extreme
distension the stomach pushes everything out of the way, and occupies all the
room between the liver and the umbilicus. When empty and contracted, it
retreats behind the liver, and lies flat in front of the pancreas at the back of the
abdomen; thus giving rise to the hollow termed the "pit of the stomach." But
59
930 LANDMARKS, MEDICAL AND SURGICAL.
as tlie stomacli distends, it makes a considerable fulness wliere there was a pit.
The middle of the transverse colon lies above the umbilicus, occupying space
(vertically two or three inches) according to its distension. Behind and below
the umbilicus, supposing the bladder contracted, are the small intestines, covered
by the great omentum.
64. Peritoneum. — The peritoneum is in contact with the linea alba all the
way down to the pubes, when the bladder is empty. But when the bladder
distends, it raises the peritoneum from the middle line above the pubes ; so that
with a bladder distended halfway up to the umbilicus, there is a space of nearly
two inches above the symphysis where the bladder may be tapped without risk
of injury to the peritoneum. For the same reason, we have space sufficient for
the successful performance of the high operation for stone. This fact in anatomy
must have been well understood by Jean de Dot, the smith at Amsterdam, who,
in the seventeenth century, cut himself in the linea alba above the pubes, and
took out of his bladder a stone as large as a hen's egg. The stone, the knife,
and the portrait of the operator, may be seen to this day in the museum at
Ley den.
65. Bivision of Aorta. — The aorta generally divides at a point about one
inch and a half below the umbilicus. A more reliable guide to this division
than the umbilicus, is a point (a very little to the left) of the middle line about
the level of the highest part of the crest of the ilium. A line drawn with a
slight curve outwards from this point to the groin, where the pulsation of the
common femoral can be distinctly felt (rather nearer to the pubes than the ilium),
gives the direction of the common iliac and external iliac arteries. About the
first two inches of this line belong to the common iliac, the remainder to the
external. Slight pressure readily detects the pulsation of the external iliac
above "Poupart's ligament."
I have given the length of the common iliac as about two inches. As a rule,
this is correct; but it should be remembered there are frequent deviations. I
have seen it any length between three-quarters of an inch and three inches and
a half. These varieties may arise either from a high division of the aorta, or a
low division of the common iliac, or both. It is impossible to ascertain during
life what is its length in a given instance ; for there is no necessary relation
between its length and the height of the stature. I have seen it very short in
tall men and vice versd. Anatomists generally describe the left as a trifle longer
than the right; but from an examination of a hundred bodies, I found their
average length to be pretty nearly the same.
66. Mr. Abernethy, who in the year 1796 first put a ligature round the exter-
nal iliac, made his incision in the line of the artery. But the easiest and safest
way to reach the vessel is by an incision (recommended in the first instance by
Sir Astley Cooper, and now generally adopted), beginning just on the inner side
of the artery, a little above Poupart's ligament, and continued upwards and
outwards a little beyond the spine of the ilium. The same incision extended
further in the same direction would reach the common iliac.
67. Bony Prominences. — Tlie anterior superior spine of the ilium, the
spine of tiie pubes, and the line of Poupart's ligament are landmarks with which
every surgeon should be thoroughl}'- familiar.
68. Spine of Ilium. — The spine of the ilium is the spot from which we
measure the length of the lower extremity. It is a valuable landmark in
determining the nature of injuries to the pelvis and the hip. The thumb easily
feels the spine, even in fat persons. Its position with regard to the trochanter
major should be carefully examined. The best way to do this is to place the
thumbs firmly on the opposite spines, and to grasp the trochanters with the
fingers. Any abnonnul position on one side is thus easily ascertained with the
second side as a giii<li'.
69. Spines of Pubes. — The si)inc of the pubes is the best guide to the ex-
ternal abdominal ring. It cannot easily be felt by placing the finger directly
THE ABDOMEN. 931
over it, since it is generally covered bj fat. To feel it distinctly, we sliould
push np the skin of the scrotum and get beneath the subcutaneous fat. If there
be any diificulty in finding it, abduct the thigh, and the tense tendon of the
adductor longus will lead up to it.
The position of the spine of the pubes is appealed to as a means of diagnosis
in doubt between inguinal and femoral hernia. The spine lies on the outer side
of the neck of an inguinal hernia, on the inner side of the neck of a femoral.
The spine of the pubes is nearly on the same horizontal line as the upper
part of the trochanter major. In this line, about one full inch external to the
spine, is the femoral ring. Here is the seat of stricture in a femoral hernia.
70. Poupart's Ligament, or Crural Arch. — The line of Poupart's liga-
ment (crural- arch) is in most persons indicated by a slight crescent-like furrow
along the skin. It corresponds with a line drawn not straight, but with a gentle
curve downwards from the spine of the ilium to the spine of the pubes. With
the help of the preceding landmarks it is easy to find the exact position of the
external and internal abdominal rings, and the direction of the inguinal canal.
71. Abdominal Rings. — The external abdominal ring is situated imme-
diately above the spine of the pubes. It is an oval opening with the long axis
directed obliquely downwards and inwards. Though its size varies a little
in different persons, yet as a rule it will admit the end of the little finger, so
that we can tell by examination whether it be free or otherwise. To ascertain
this, the best way is to push up the thin skin of the scrotum before the finger :
then, by tracking the spermatic cord, the finger readily glides over the crest of
the pubes and feels the sharp margins of the ring.
The precise position of the internal ring is about midway between the spine
of the ilium and the symphysis of the pubes, and about two-thirds of an inch
above Poupart's ligament,
72. Inguinal Canal. — -The position of the external and internal abdominal
rings being ascertained, it is plain that the direction of the inguinal canal must
be obliquely downwards and inwards, and that its length in a well-formed adult
male is from one and a half to two inches, according as we include the openings
or not. In very young children the canal is much shorter and less oblique, the
inner ring being behind the outer. With the growth of the pelvis in its trans-
verse direction, the anterior spines of the ilia become further apart, and thus
draw the internal ring more and more away from {i. e. to the outer side of) the
external.
73. Spermatic Cord.- — -The spermatic cord can be felt as it emerges through
the external ring, and its course can be tracked into the scrotum. The vas
deferens can be distinctly felt at the back of the cord, and separated from its
other component parts.
74:. Epigastric Artery. — The direction of the internal epigastric artery
corresponds with a line drawn from the inner border of the internal ring up the
middle of the rectus muscle, towards the chest.
In thin persons the absorbent glands which lie along Poupart's ligaments can
be distinctly felt. They are usually oval, with their long axes parallel to the
line of the ligament.
75. Abdominal Viscera. — ISTow let us see how far we can make out ex-
ternally the position and size of the abdominal viscera.
To make this examination with anything like success, it is desirable to relax
the abdominal muscles. The man should be on his back, the head, shoulders,
and thorax being well raised, to relax the recti muscles ; and the thighs bent
on the abdomen, to relax the several fascise attached to the crural arch. To
induce complete relaxation where a very careful examination is desired, chloro-
form should be given.
In manipulating the abdomen we should not use the tips of the fingers. This
is sure to excite the contraction of the muscles. The flat hand should be gently
pressed upon it, and with an undulating movement.
932 LANDMARKS, MEDICAL AND SURGICAL.
76. It is well to bear in mind tliat the central tendon of the diaphragm is
about the level of the lower end of the sternum or the junction of the seventh
rib ; that the right half of the diaphragm rises to about the level of the fifth
rib — that is, about an inch below the nipple ; that the left half does not rise so
high. In tranquil breathing the diaphragm descends about half an inch.
The position of the abdominal viscera varies, to a certain extent, in diflerent
persons. In some of them, especially the stomach, their position varies in the
same person at different times.
Let us take, first, the largest of the abdominal viscera — the liver.
77. Liver. — The liver lies under the right hypochondrium, and passes across
the middle line over the stomach into the left hypochondrium, generally speak-
ing, as far as the left mammary line. The extent to which it can be felt below
the edges of the ribs depends upon whether it is enlarged or not, and also upon
the amount of flatus in the stomach and intestines. As a rule, in health its
lower thin border projects about half an inch below the costal cartilages, and
can be felt moving up and down with the action of the diaphragm ; but it
requires an educated hand to feel it. An uneducated hand would miss it alto-
gether. That part of it, however, which crosses the middle line below the ensi-
form cartilage is much more accessible to the feel ; here it lies immediately
behind the linea alba, and in front of the stomach, nearly half-way down to the
umbilicus. Here, therefore, is the best place to feel whether the liver be en-
larged or pushed down lower than it ought to be. If it be much enlarged and
much lower, even the most untutored hand could detect its edge.
Even if the edge of the liver be felt very much lower than is normal below
the ribs, it does not necessarily follow that the liver is enlarged, since it may be
pressed down by other causes — for instance, the habit of wearing tight stays.
To what height does the liver ascend ? This can only be ascertained by care-,
ful percussion of the chest- wall. The highest part of its convexity on the right
side is about one inch below the nipple, or nearly on a level with the external
and inferior angle of the pectoralis major. Posteriorly the liver comes to the
surface below the base of the right lung, about the level of the tenth dorsal
spine.
Eoughly speaking, the upper border of the liver corresponds with the level
of the tendinous centre of the diaphragm : that is, the level of the lower end
of the sternum. Thus a needle thrust into the right side, between the sixth
and seventh ribs, would traverse the lung, and then go through the diaphragm
into the liver.
78. Gall Bladder. — The gall bladder, or rather the fundus of it, is situated,
but cannot be felt, just below the edge of the liver about the ninth costal carti-
lage, outside the edge of the right rectus muscle.
79. Stomach. — The stomach varies in wsize more than any other organ in
the body. Wlicn empty and contracted (63) it lies at the back of the abdomen,
overlapped by the left lobe of the liver, and in front of the pancreas. When
very full, it turns on its axis and swells up towards the front, coming close
behind the wall of the abdomen, occupying most of the left hypoclioudrium
and epigastrium, displacing the contiguous organs, pushing in every direction,
and often interfering with the action of the heart and left lung. Hence the
palpitation and distressing heart-symptoms in indigestion and flatulence.
The cardiac orifice of the stomach lies to the left of the middle line, just
below the level of the junction of the seventh costal cartilage with the sternum.
80. Pylorus. — The pylorus lies under the liver, on the right side, near the
end ()(■ llic, ciiitiliigc of Ihe eighth rib; but it cannot be felt unless enlarged and
hardened by disease, and even then not with certainty.
81. Spleen. — The spleen, if healthy, cannot be felt, so completely is it
sheltered by the ribs. It lies on tlie lefit side, connected to the great end of the
stomach, beneath the ninlli, tenth, and eleventh ribs, between the axillary lines —
lines, namely, dirawn vertically downwards from the anterior and posterior
THE ABDOMEN. 933
margins of tlie axilla. Its upper edge is on a level with tlie spine of tlie nintli
dorsal vertebra, its lower with the spine of the eleventh.
Its position and size, therefore, in health can only be ascertained, and not very
accurately, by the extent of dulness on percussion. The greatest amount of
dulness would be over the tenth and eleventh ribs ; above this the thin edge of
the lung would intervene between the spleen and the abdominal wall. If, there-
fore, the spleen can be distinctly felt below the ribs, it must be enlarged. In
proportion to its enlargement, so can its lower rounded border be detected below
"the tenth and eleventh ribs, especially when forced downwards by a deep inspi-
ration.^
82. Pancreas. — The pancreas lies transversely behind the stomach, and
crosses the aorta and the spine about the junction of the first and second lumbar
vertebrge. The proper place to feel for it, therefore, would be in the linea alba
about two or three inches above the umbilicus. Is it perceptible to the touch ?—
only under very deep pressure, and very favorable circumstances, such as an
emaciated and empty abdomen. It is worth remembering that it may be felt
under such conditions. Sir W. Jenner says that he has known the pancreas of
normal size, in thin persons mistaken for disease — disease of the transverse arch
of the colon, or aneurism of the abdominal aorta.
83. Kidney. — The kidney lies at the back of the abdomen, on the quadratus
lumbornm and psoas muscles, opposite the two lower dorsal and two upper
lumbar spines. The right, owing to the size of the liver, is a trifle — say, three-
quarters of an inch — lower than the left. The pelvis of the kidney is about the
level of the spine of the first lumbar vertebra: the upper border is about the
level of the space between the eleventh and twelfth dorsal spines; the lower
border comes as low as the third lumbar spine. During a deep inspiration both
kidneys are depressed by the diaphragm nearly half an inch.
Can we feel the normal kidney? The only place where it is accessible to
pressure is just below the last rib, on the outer edge of the "erector spinse." I
say accessible to pressure, for I have never succeeded in satisfying myself that
I have distinctly felt its rounded lower border in the living subject, nor even in
the dead, with the advantage of flaccid abdominal walls and the opportunity of
making hard pressure with both hands, placed simultaneously, one in front of
the abdomen, the other on the back. For these reasons I believe that, although
we can easily ascertain its degree of tenderness on pressure, we cannot actually
feel it unless it be considerably enlarged.
We must be on our guard not to mistake for the kidney an enlarged liver or
spleen, or an accumulation of feces in the lumbar part of the colon.
84. Large Intestine. — Let us now trace the large intestine and see where
it is accessible to pressure. The "c^cum," or "caput coli," and the ileo-caecal
valve lie in the right iliac fossa. The ascending colon runs up the right lumbar
region over the right kidney. The transverse colon crosses the abdomen two
or three inches above the umbilicus. The descending colon lies in the left
lumbar region in front of the left kidney. The sigmoid flexure occupies the
left iliac fossa.
Throughout the whole of this tortuous course, except at the angles of the
transverse colon, the large bowel is accessible to pressure, and we could, under
favorable circumstances, detect hardened feces in it. "Within the last few
months we have had two instances of this in St, Bartholomew's Hospital. One
was a collection of feces in the transverse colon, which formed a distinct tumor
in the abdomen. All the symptoms yielded to large and repeated injections of
olive oil. The other case was an accumulation of fecal matter in the sigmoid
flexure, which during life was thought to be malignant disease.
85. Colotomy. — The operation of opening the colon (colotomy) may be done
' See some good observations on the position of the enlarged spleen by Sir W. Jenner, " Med.
Gaz.," Jan. 16, 1869.
934 LANDMARKS, MEDICAL AND SURGICAL.
in tlie right or left loin, below tlie kidney, in that part of the colon not covered
by peritoneum.
The landmarks of the operation are : — (1) The last rib, of which feel the sloping
edge; (2) the crest of the ilium; (3) the outer border of the "erector spinee."
The incision should be about three inches long, midway between the rib and
the ilium. It should begin at the outer border of the "erector spinse," and
should slope downwards and outwards in the direction of tlie rib. The edge of
the "quadratus lumborum," which is the guide to the colon, is about one inch
external to the edge of the "erector spinee," or three full inches from the lumbar
spines. The line of the gut is vertical, and runs (for a good two inches) between
the lower border of the kidney and the iliac crest.
Small Intestines. — AH the room below the umbilicus is occupied by the
small intestines. The coils of the jejunum lie nearer to the umbilicus (one
reason of the great fatality of umbilical hernise). Those of the ileum are lower
down.
On the right side, a little below the ninth rib, the colon lies close to the gall
bladder, and is, after death, sometimes tinged with bile. Posteriorly, this part
of the colon is in contact with the kidney and duodenum.
86. Bladder. — When the bladder distends, it gradually rises out of the pelvis
into the abdomen, pushes the small intestines out of the way, and forms a swell-
ing above the pubes, reaching in some instances up to the navel. The outline
of this swelling is perceptible to the hand as well as to percussion. More than
this, fluctuation can be felt through the distended bladder by tapping on it in
front with the fingers of one hand, while the forefinger of the other passed up
the rectum feels the bottom of the "trigone."
THE PERINEUM.
The body is supposed to be placed in the usual position for lithotomy.
87. Bony Framework. — We can readily feel the osseous and ligamentous
boundaries of the perineum ; namely, the rami of the pubes and ischia, the
tuberosities of the ischia, the great sacro-ischiatic ligaments, and the apex of
the coccyx. This framework forms a lozenge- shaped space. If we draw an
imaginary line across it from the front of one tuber ischii to the other, we divide
this space into an anterior and a posterior triangle. The anterior is nearly
equilateral, and, in a well-formed pelvis, its sides are from three to three and a
half inches long. It is called the urethral triangle. The posterior, containing
the greater part of the anus and the ischio-rectal fossa on each side, is called the
anal triangle.
88. Raphe. — A slight central ridge of skin, called the "raph^," runs from the
anus up tlie perineum, scrotum, and penis. This "raphe," or middle line of the
perineum, is the "line of safety" in making incisions to let out matter or cfi'used
urine, or to divide a Rtriduro.
89. Central Point of Perineum. — It is very important to know that a
point of the raplie about midway between the scrotum (where it joins the peri-
neum) and the centre of the anus, corresponds with the so-called "central ten-
don" where the perineal muscles meet. The bulb of the urethra lies above this
point, and never, at any age, comes lower down. The artery of the bulb, too,
never runs below this level. Therefore the incision in litliotomy should never
commence above it, A knife introduced at this point, and pushed backwards
with a very slight inclination upwards, would enter the membranous part of the
urethra just in front of the prostate gland; pushed still further it would enter
the neck of the bladder. This point, then, is a very good landmark to the
urethra in lithotomy, or, indeed, in any operations on the perineum.
The incision in the lateral operation of lithotomy, beginning below the point
indicated, should be carried downwards and outwards between the anus and the
THE PERINEUM. 935
ischium, a little nearer to tlie iscliium tlian the anus. The lower end of the
incision should reach a point just below the anus.
90. Triangular Ligament. — In a thin perineum, we can feel the lower
border of the deep perineal fascia or "so-called triangalar" ligament of the
urethra. The urethra passes through it about one inch below the lower part of
the symphysis pubis, and about three-quarters of an inch higher than the central
tendon of the perineum. It is important to bear in mind these landmarks in
introducing a catheter. If the catheter be depressed too soon, its passage will
be resisted by the triangular ligament ; if too late, it will be likely to make a
false passage by running through the bulb.
91. Anus.' — One of the most important landmarks which guide a surgeon in
his operations about the anus, is a white line which was first pointed out by
Mr. Hilton,^ and can be easily recognized in the living body. It shows the
junction of the skin and mucous membrane, and is of especial interest because
it marks with great precision the linear interval between the external and
internal sphincter muscles. It is an exact and truthful landmark, and can be
relied upon. From this line the internal sphincter extends upwards, beneath
the mucous membrane, for about an inch, becoming gradually more and more
attenuated.
The wrinkled appearance of the anus is caused by the contraction of the
external sphincter. At the bottom of these cutaneous folds, especially towards
the coccyx, we look for "fissure of the anus."
92. Landmarks in the Rectum. — Many valuable landmarks may be felt
by introducing the finger into the rectum, with a catheter at the same time in
the urethra. The principal of these landmarks are the following: —
a. The finger can feel the extent and powerful grasp of the internal sphincter
for about one inch up the bowel.
&. Urethra. — Through the front wall of the bowel it can most distinctly feel
the track of the membranous part of the urethra, exactly in the middle line.
This is very important, because you can ascertain with precision whether the
catheter has deviated from the proper track.
c. Prostate Gland. — About an inch and a half or two inches from the anus,
the finger comes upon the prostate gland. The gland lies in close contact witii
the bowel, and can be detected by its shape and hard feel. The finger, moved
from side to side, can examine the size of its lateral lobes.
d. The finger, introduced still further, can reach beyond the prostate, as far
as the apex of the trigone of the bladder. More than this, it can feel the angle
between the "ductus communes ejaculatorii," which forms the apex of the tri-
gone. This is the precise spot where the distended bladder should be punctured
through the rectum. The more distended the bladder, the easier can this spot
be felt. Fluctuation is at once detected by a gentle tap on the bladder above
the pubes (86). The trocar must be thrust in the direction of the axis of the
distended bladder; that is, roughly speaking, in a line drawn from the anus
through the pelvis to the umbilicus.
e. The folcl of peritoneum, called the recto-vesical pouch, is about four inches
from the anus, therefore it is not within reach of the finger; and we run no
risk of wounding it in tapping the bladder if the trocar be introduced near the
angle of the trigone.
/. The finger can feel one of the ridges or folds of mucous membrane which
are situated at the lower part of the rectum. This fold projects from the side,
and sometimes from the upper part of the rectum, near the prostate. When
thickened or ulcerated, this fold occasions great pain in defecation ; and great
relief is afforded by its division.
g. Lastly, the finger can examine the condition of the spaces filled with fat
on either side of the rectum, called the ischio-rectal foss^, with a view to
' "Lectures on Rest and Pain," p. 280.
936 LANDMARKS, MEDICAL AND SURGICAL.
ascertain the existence of deep-seated collections of matter, or the internal com-
munications of fistulge.
Introduction of Catheters. — In the introduction of catheters the following
are good rules. Keep the point of the instrument well applied against the
upper surface of the urethra : — Depress the handle at the right moment (90) ;
keep the umbilicus in view ; in cases of dif&culty feel the urethra through the
rectum, to ascertain whether the instrument be in the right direction. Atten-
tion to these rules diminishes the risk of making a false passage.
Uretlira in the Child. — In children the membranous part of the urethra is,
relatively speaking, very long, owing to the smallness of the prostate. It is
also more sharply curved, because the bladder in children is more in the abdo-
men than in the pelvis. It is, moreover, composed of thin and delicate walls.
The greatest gentleness, therefore, should be used in passing a catheter ; else
the instrument is likely to pass through the coats and make a false passage.
Hence the advantage of being able to ascertain through the rectum whether the
instrument be in the right track and moving freely in the bladder, which can
also be easily felt in children.
THE THIGH.
93. Poupart's Ligament, or Crural Arch. — Mark the anterior superior
spine of the ilium, the spine of the pubes, and define the line of "Poupart's liga-
ment" which extends between them. This line is one of our guides in the
diagnosis of inguinal and femoral hernias. If the bulk of the tumor be above
the line, the hernia is probably inguinal ; if below it, femoral. The line is not
a straight one drawn from the spine of the ilium to the spine of the pubes, but-
slightly carved, with the convexity downwards, owing to its close connection
with the fascia lata of the thigh. In many persons it can be distinctly felt ; in
nearly all its precise course is indicated by a slight furrow in the skin.
Fof the points about the spine of the pubes, refer to paragraph 69.
94. Furrow at the Bend of the Thigh, — When the thigh is even slightly
bent, there appears a second furrow in the skin below that at the crural arch.
This second furrow begins at the angle between the scrotum and the thigh,
passes outwards, and is gradually lost between the top of the trochanter and
the anterior superior spine of the ilium. It runs right across the front of the
capsule of the hip-joint. For this reason it is a valuable landmark in amputa-
tion at the hip-joint. The point of the knife should be introduced externally
where the furrow begins, should run precisely along the line of it, and come out
where it ends; so that the capsule of the joint may be opened with the first
thrust. In suspected disease of the hip pressure made in this line, just below
the spine of the ilium, will tell us if the joint be tender. Effusion into the joint
obliterates all trace of the furrow, and makes a fulness when contrasted with
the o])posite groin.
95. Saphenous Opening. — In most persons there is a natural depression
over the saphenous opening in the fascia lata, where the saphena vein joins the
femoral. The position of this opening is jast below the inner third of Poupart's
ligament, and about an inch and a half external to the spine of the pubes. This
is the place where the swelling of a femoral hernia first appears : therefore it
ouglit to be carcfnlly examined in cases of doubt.
90. Femoral Ring.— ^Fhc position of the femoral ring, through which the
hernia csi-npcs (Vom the abdomen, is, on a dee])cr plane, aI)out half an inch
higher than the sa])hcnous opening, and immediately under Poupart's ligament.
As the plane of the ring is vertical in the supine position of the body, the way
in whicli we should try to reduce a femoral hernia is by pressure, applied first
in a downward direction, aflcrwards in nn upward. The intestine protruded
has to pass back under a sharp edge of fascia, namely, tlie upper horn of the
THE THIGH. 937
saphenous opening (known as Hej's ligament). At tlie same time we bend the
thigh, to relax the fascia as much as possible.
A good way to find the seat of the femoral ring with precision is the follow-
ing : Feel for the pulsation of the femoral artery on the pubes ; allow half an
inch (on the inner side) for the femoral vein ; then comes the femoral ring.
In performing the operation for the relief of the stricture in femoral hernia
the incision through the skin should be about an inch and a half external to the
spine of the pubes. Its direction should be vertical, and its middle should be
just over the femoral ring.
97. Lymphatic Glands in the Groin. — The cluster of inguinal and femo-
ral lymphatic glands can sometimes be felt in thin persons. The inguinal
lie for the most part along the line of Poupart's ligament : they receive the
absorbents from the wall of the abdomen, the urethra, the penis, the scrotum,
and the anus. The femoral glands lie chiefly over the saphenous opening and
along the outer side of the saphena vein : they receive the absorbents of the
lower extremity ; they receive some also from the scrotum — of which we have
practical evidence in cases of chimney-sweeper's cancer.
98. Trochanter Major. — The trochanter major is a most valuable landmark,
to which we are continually appealing in injuries and diseases of the lower
extremity. There is a natural depression over the hip (in fat persons) where it
lies very near the surface, and can be plainly felt, especially when the thigh is
rotated. Nothing intervenes between the bone and the skin except the strong
fascia of the glutaaus maximus and the great bursa underneath it.
The top of the trochanter lies pretty nearly on a level with the spine of the
pubes, and is about three-fourths of an inch lower than the top of the head of
the femur. A careful examination of the bearing of the great trochanter to the
other bony prominences of the pelvis, and a comparison of its relative position
with that of the opposite side, are the best guides in the diagnosis of injuries
about the hip, and the position of the head of the femur.
99. Nelaton's Line. — " If in the normal state you examine the relations of
the great trochanter to the other bony prominences of the pelvis, you will find
that the top of the trochanter corresponds to a line drawn from the anterior
superior spine of the ilium to the most prominent part of the tuberosity of the
ischium. This line also runs through the centre of the acetabulum. The extent
of displacement in dislocation or fracture is marked by the projection of the
trochanter behind and above this line."^
"Nelaton's line," as it is termed, theoretically holds good. But in stout per-
sons it is not always easy to feel these bony points so as to draw the line with
precision. A surgeon must, after all, in many cases trust to measurement by
his eyes and his flat hands — his best guides. Thus, let the thumbs be placed
firmly on the spines of the ilia, while the fingers grasp the trochanters on each
side. Having the sound side as a standard of comparison the hand will easily
detect any displacement on the injured side. Winslow's^ observation is very
much to the point — ^'■Feel whether the injured member answers to the sound."
The top of the great trochanter is the guide in an operation recentlj^ intro-
duced by Mr. Adams, namely, the " subcutaneous section of the neck of the
femur." " The puncture should be made one inch above and nearly one inch in
front of the top of the trochanter. The neck of the bone is to be sawn through
at right angles to its axis, the saw working parallel to Poupart's ligament, and
about one inch below it."
Spine of the Ilium. — The anterior superior spine of the ilium is the point
from which we measure the length of the lower limb. By looking at the spines
of opposite sides we can detect any slant in the pelvis. By pressure on both
spines simultaneously we examine if there be a fracture of the pelvis, or disease
at the sacro-iliac joint.
' N61aton, " Pathologie chirursricale," t. iv. p. 441. 1848.
2 Wiuslow, " Structure of the Human Body." London, 1733.
938 LANDMAEKS, MEDICAL AND SURGICAL.
100. " In reducing a dislocation of the laip hj manipulation it is important to
bear in mind that, in every position, the head of the femur faces nearly in the
direction of the inner aspect of its internal condyle."^
101. Compression of Femoral Artery. — About a point midway between
the spine of the ilium and the symphysis pubis, the femoral artery can be felt
beating, and effectually compressed, against the pubes. How should the pres-
sure be applied when the patient lies on the back ? In accordance with the
slope of the bone — -that is, with a slight inclination upwards.
If the Italian tourniquet be used, we should be careful to adjust the counter-
pad well under the tuberosity of the ischium. If digital pressure be used, it is
easy to command the femoral by slight pressure of the thumb, provided the
fingers have a firm hold on the great trochanter.
102. Sartorius. — The sartorius is the great fleshy landmark of the thigh, as
the biceps is of the arm, and the sterno-cleido-mastoideus of the neck. Its
direction and borders may easily be traced by asking the patient to raise his
leg, a movement which puts the muscle in action. The same action defines the
boundaries of the triangle (of Scarpa) formed by Poupart's ligament, the ad-
ductor longus and sartorius.
Line of Femoral Artery. — To define the course of the femoral artery, draw
a line from midway between the anterior superior spine of the ilium and the sym-
physis pubis to the (spur-like) tubercle for the adductor magnus on the inner
side of the knee. The femoral artery lies under the upper f of this line.
The sartorius begins to cross the artery, as a rule, from three to four inches
below Poupart's ligament. The point at which the profunda artery arises is
(generally) about one and a half or two inches below the ligament. Therefore
the incision for tying the femoral in Scarpa's triangle should commence about a
hand's breadth below Poupart's ligament, and be continued for three inches in-
the line of the artery.
To command the femoral in Scarpa's triangle, the pad of the tourniquet
should be placed at the apex, and the direction of the pressure should be, not
backwards, but outwards, so that the artery may be compressed against the
femur.
In the middle third of the thigh the femoral artery lies in Hunter's canal
overlapped by the sartorius. About the commencement of the lower third the
artery leaves the canal through the oval opening in the adductor magnus, and
enters the popliteal space. The line for finding the artery in Hunter's canal
has been already traced. The incision to reach the artery in this part of its
course would fall in with the outer border of the sartorius.
To command the femoral artery in Hunter's canal, the pressure should be
directed outwardly, so as to press the vessel against the bone.
TRE BUTTOCKS.
103. Bony Landmarks. — Tlie bony landmarks of- the buttocks which can
be distinctly felt are: 1, the posterior superior spines of the ilia; 2, the spines
of the sacral vertebr£e; 3, the two tubercles of the last sacral vertebra; 4, the-
apex of the coccyx in the deep groove leading to the anus; 5, the tuberosities
of the iscliia on each side of the anus.
The posterior spines of the ib"a arc about the level of the second sncral sjiine,
and correspond with the middle oftlie sacro-iliac symphysis.
The third sacral spine marks the lowest part to which the ccrcbro-spinal
fluid descends in the spinal canal.
The tuberosities of the ischia, in the erect position, are covered by the glutajus
maximus. In the sitting position they support the weight of the body, and are
' Bigelow, "Mecliunism of Dislocation and Fniclurc of the Hi})." riiiUul(l|ilila, 1869.
THE KNEE. 939
only covered by a tliick pad of coarse fat. Between tliis pad and the bones
there is a bursa, which. I have more than once seen enlarged and inflamed in
coachmen.
The prominence of the nates is one of the characteristics of man in connection
with his erect attitude. "Les fesses n'appartiennent qu'^ I'esp^ce humaine."
They are formed of an accumulation of fat over the great muscle of the buttock
(glutfeus maximus). From their appearance we may gather some indication of
the state of the constitu.tion. They are firm and globose in the vigorous ; loose
and flaccid in the infirm. Wasting and flattening of one compared -with the
other, is an early symptom of disease in the hip.
104. Fold of the Buttock. — The deep furrow, termed " the fold of the but-
tock," which separates the nates from the back of the thigh, corresponds with
the lower border of the giutseus maximus. Its altered direction in disease of
the hip is very characteristic. This is the best place to feel the great ischiatic
nerve. We find it by pressing deep between the trochanter and the tuber ischii
rather nearer to the latter. When we sit upright, the nerve is not liable to
pressure ; but it becomes numbed when we sit long sideways.
105. Gluteal Artery.— To find at what point the gluteal artery comes out
of the pelvis, draw a line from the posterior superior spine of the ilium to the
trochanter major, rotated inwards. The junction of the upper with the middle
third of this line lies over the artery as it emerges from the upper border of the
great ischiatic notch.
Tbe point of exit of the ischiatic artery from the pelvis is about half an inch
lower than that of the gluteal.
106. Pudic Artery. — The pudic artery lies over the spine of the ischium.
To find it, draw a line from the outer side of the tuber ischii to the posterior
superior spine of the ilium. The junction of the lower with the middle third
gives the position of the artery. The ischiatic artery lies close to it, but nearer
the middle line.
Looking at the course of these arteries it appears that when seated on hard
seats the pressure is sustained by the bones ; when reclining on soft seats the
pressure is sustained more by the soft parts, and reaches the arteries ; hence
the tendency of modern modes of reposing to drive the blood into the interior
of the pelvis and favor the production of piles and uterine disorders. A cele-
brated French accoucheur used to say that the fashion of high waists, tight
lacing, and easy chairs brought him many thousands a year.
THE KNEE.
107. Bony Points. — -The patella ; the tuberosities of the two condyles ; the
tubercle of the tibia for the attachments of the ligamentum patellee ; another
(the lateral) tubercle, on the outer side of the head of the tibia; and the head
of the fibula are the chief bony landmarks of the knee.
Observe that the head of the fibula lies at the outer and back part of the
tibia, and that it is pretty nearly on a level with the tubercle for the attachment
of the ligamentum patellse.
We can also feel the little spur-like projection of bone above the internal con-
dyle which gives attachment to the tendon of the adductor magnus. The spur-
like projection corresponds with the level of the epiphysis of the lower end of
the femur, and also with the level of the highest part of the trochlea for the
patella ; facts worth notice in performing excision of the knee.
" In reducing a dislocation of the hip, it is important to bear in mind that the
inner aspect of the internal condyle in every position of the limb faces nearly
in the direction of the head of the femur." (100.)
The tubercle on the outer side of the head of the tibia gives attachment to
the broad and strong aponeurosis (tendon of the tensor fascia), which, acting
940 LANDMARKS, MEDICAL AND SURGICAL.
like a brace for the support of tlie pelvis, is well seen in emaciated persons
down the outer side of the thigh. This tubercle indicates the level to which
the condyles of the femur descend, and the lower level of the synovial mem-
brane.
The patella, in extension of the knee, is nearly all of it above the condyles ;
in flexion, it lies in the iuner-condyloid fossa (more on the external condyle),
and thus protects the joint in kneeling. Its inner border is thicker and more
prominent than the outer, which slopes down towards its condyle.
108. Ligamentum PatellEe. — The line of the ligamentum patellee is vertical.
Hence any deviation from this line, one way or the other, indicates more or less
dislocation of the tibia. There is a pellet of fat under the ligament, which an-
swers a " packing" purpose — sinking in when the knee is bent, rising when the
knee is extended, and bulging on either side of the tendon, almost enough to
give the feel of fluctuation.
In a well-formed leg the ligamentum patellae, the tubercle of the tibia, and
the middle of the ankle should be in the same line. A useful point in the ad-
justment of fractures.
109. Patellar Bursa. — The patellar or housemaids' bursa is situated not
only over the patella, but over the upper part of the ligament. This is plain
enough when the bursa becomes enlarged. There is another subcutaneous
bursa over the insertion of the ligament into the tubercle of the tibia. This is
quite independent of the deep bursa between the tendon and the bone.
110. Synovial Membrane of Knee. — The synovial membrane of the knee,
when the joint is extended, rises like a cul-de-sac above the upper border of the
patella about two inches. It ascends, too, a little higher under the vastus in-
ternus than the vastus externus — a fact very manifest when the joint is dis-
tended. When the knee is bent this cul-de-sac is drawn down — hence the rule -
of bending the knee in operations near the lower end of the femur.
The lower level of the synovial membrane of the knee is just above the level
of the upper part of the head of the fibula. The tibio-fibular synovial mem-
brane is, as a rule to which there are few exceptions, independent of that of the
knee.
111. Popliteal Tendons. — The tendons forming the boundaries of the pop-
liteal space can be distinctly felt when the muscles which bend the knee are
acting. On the outer side, we have the biceps running down to the head of the
fibula. On the inner side, we feel three tendons, disposed as follows : nearest
to the middle of the popliteal space is the semitendinosus, very salient and
traceable high up the thigh ; next comes the thick round tendon of the semi-
membranosus; still more internally is the gracilis. The sartorius, which forms
a graceful muscular prominence on the inner side of the knee, does not become
tendinous until it gets below it.
112. Popliteal Bursa. — The precise position of the bursa in the popliteal
space, whicli sometimes enlarges to the size of a hen's egg, is between the tendon
of the inner head of the gastrocnemius and the tendon of the semimembranosus,
just where they rub one against the other. The bursa is from one and a half
to two inches long. Wlicn enlarijed, it makes a swelling; on the inner side of
the popliteal space, which bulges and becomes tense when the knee is extended
and vice versS,, I examined 150 bodies with a view to ascertain how often this
bursa communicates with the synovial membrane of the knee. There was a
communication about once in five instances. This should make us cautious in
intci-rcriiiL'" 1oo ronuhly wilh the bursa when enhirged.
ll'>. Popliteal Artery. — The po])litcal artery can be felt beating nnd can
be compressed against tlie back of the femur, close to which it lies. But ]ires-
sure, sufficient to stop the blood, should be firm, and should be made against
the bone nearer to the inner than the outer hamstrings. 'V\\r. line of tlie artery
corresponds with the middle of the hnm. It lies under cover of the fleshy belly
of the semimembranosus, and the outer border of this muscle is the guide to it.
THE LEG AND ANKLE. 941
An incision down tlie middle of the ham wonld fall in with the vessel just
above the condyles.
Hi. Peroneal Nerve. — The peroneal nerve runs parallel with and close to
the inner border of the tendon of the biceps. It can be felt in thin persons.
There is a risk of dividing it in tenotomy of the biceps, unless the knife be
carefully introduced from within outwards. Below the knee the nerve can be
felt close to the fibula just below the head.
THE LEG AND ANKLE.
115. Bony Points. — The tubercle of the tibia (for the attachment of the
ligamentum patellee), the sharp front edge called the shin, and the broad flat
subcutaneous surface of the bone can be felt all the way down. The inner edge
can be felt too, but not so plainly. The lower third is the narrowest part of
the bone and the most frequent seat of fracture.
The head of the fibula is a good landmark on the outer side of the leg, about
one inch below the top of the tibia and nearly on a level with the tubercle.
Observe that it is placed well back, and that it forms no part of the knee-joint,
and takes no share in supporting the weight.
The shaft of the fibula arches backwards, the reverse of the shaft of the tibia.
The fact of the bones not being on the same plane should be remembered in flap
amputations. The shaft of the fibula is so buried amongst the muscles, that the
only part to be distinctly felt is the lower fonrth. Here there is a flat surface,
subcutaneous, between the peroneus tertius in front, and the two peronei (lon-
gus and brevis) behind. Here is the most frequent seat of fracture.
116. Malleoli.— The shape and relative position of the malleoli should be
carefully studied, as the great landmarks of the ankle. The inner malleolus
does not descend so low as the outer, and advances more to the front: at the
same time, owing to its greater antero-posterior depth, it is on the same plane
as the outer behind. The lower border of the inner malleolus is somewhat
rounded, and the slight notch in it for the attachment of the lateral ligament
can be felt. The outer malleolus descends lower than the inner, thus effectually
locking the joint on the outer side. Its shape is not unlike the head of a
serpent. Viewed in profile, it lies just in the middle of the joint.
In Syme's amputation of the foot at the ankle, the line of the incision should
run from the apex of the outer malleolus, under the sole, to the centre of the
inner.
In a well-formed leg, the inner edge of the patella, the inner ankle, and the
inner side of the great toe, should be in the same vertical plane. Look to these
landmarks in adjusting a fracture or dislocation, keeping at the same time an
eye upon the conformation of the opposite limb.
There are several strong tendons to be seen and felt about the ankle.
117. Tendo AcMUis. — Behind is the tendo Achillis. It forms a high relief,
with a shallow gutter on each side of it. The narrowest part of the tendon,
where it should be divided in tenotomy, is about the level of the inner ankle,
below this it expands again to be attached to the lower and back part of the os
calcis. Seen in profile, the tendon is not straight, but slightly concave — being-
drawn in by an aponeurosis which forms a sort of girdle round it. This girdle
proceeds from the posterior ligament of the ankle; and, though most of its
fibres encircle the tendon, some of them adhere to and draw in its sides. All
this disappears when the tendon is laid bare by dissection,
118. Tendons behind Inner Ankle. — Above and behind the malleolus
internus we can feel the broad flat tendons of the tibiahs posticus and the flexor
longus digitorum. The tendon of the tibialis posticus lies nearest to the bone
and comes well up in relief in adduction of the foot. It lies close to, and parallel
with, the inner edge of the tibia, so that this edge is the best guide to it. There-
942 LANDMARKS, MEDICAL AND SURGICAL.
fore in tenotomy the knife should be introduced first perpendicularly between
the tendon and the bone, and then turn at right angles to cut the tendon. The
tendon has a separate sheath and synovial membrane, which commences about
one inch and a half above the apex of the malleolus, and is continued to its
insertion into the tubercle of the scaphoid bone. The proper place, then, for
division of the tendon, is about two inches above the end of the malleolus.
In a young and fat child, where the inner edge of the tibia cannot be distinctly
felt, the best guide to the tendon is a jDoint midway between the front and the
back of the ankle. An incision in front of this point might injure the internal
saphena vein ; behind this point, the posterior tibial artery.
119. Tendons behind Onter Ankle. — Behind the malleolus externus we
feel the two peroneal (long and short) tendons. They lie close to the edge of
the fibula, the short one nearer to the bone. In dividing these tendons, the
knife should be introduced perpendicular to the surface, and about two inches
above the apex of the ankle, so as to be above the synovial sheaths of the
tendons.
Tendons in front of Ankle. — Over the front of the ankle, when the
muscles are in action, we can see and feel, beginning on the inner side, the ten-
dons of the tibialis anticus, the extensor longus pollicis, the extensor longus
digitorum, and the peroneus tertius. They start up like cords when the foot is
raised, and are kept in their proper relative position by strong pulleys formed
by the anterior annular ligament. Of these pulleys the strongest is that of the
extensor communis digitorum. When the ankle is sprained, the pain and
swelling arise from a stretching of these pulleys and effusion into their syno-
vial sheaths. A laceration of one of the pulleys and escape of the tendon is
extremely rare.
The place for the division of the tendon of the tibialis anticus, so as to divide
it below its synovial sheath, is about one inch before its insertion into the
cuneiform bone. The knife should be introduced on the outer side, so as to
avoid the dorsal artery of the foot.
Now trace the lines of the arteries, and the landmarks near which they divide.
120. Popliteal Artery. — About one inch and a quarter below the head of
the fibula, or say one inch below the tubercle of the tibia, the popliteal artery
divides into the anterior and posterior tibial. The peroneal comes off from the
posterior tibial about three inches below the head of the fibula.
Consequently we may lay down, as a general rule, that, in amputations one
inch below the head of the fibula, only one main artery, the popliteal, is divided.
In amputations two inches below the head of the fibula, two main arteries, the
anterior and posterior tibial, are divided. In amputations three inches below
the head, three main arteries, the two tibials and the peroneal, are divided.
121. Anterior Tibial Artery.- — The anterior tibial artery comes in front of
the interosseous membrane, one inch and a quarter below the head of the fibula,
and here lies close to this bone. Its subsequent course is defined by a line
drawn from the front of the head of the fibula to the middle of the front of the
ankle. This line corresponds pretty nearly with the outer border of the tibialis
anticus all the way down. If this muscle be put in action, its outer border is
plainly seen, and the incision for the ligature of the artery in any part of its
course may be defined with the greatest precision. The artery can be felt
beating anrl com|)rcsscd Avhere it crosses the front of the tibia and ankle.
122. Posterior Tibial Artery. — The posterior tibial commences about one
inch and a quarter below the head of the fibula. Its subsequent course corre-
sponds with a line drawn from the middle of the upper part of the calf to the
hollmv behind the inner ankle, where it can be felt beating distinctly about half
an inch beliind the edge of the tibia. A vertical incision down the middle of
the calf would reach the artery under cover of the gastrocnemius and soleus.
A vertical incision along the middle third of the leg, about half an inch from
THE FOOT. 943
the inner edge of ttie tibia, would enable tlie operator to reacli tlie artery side-
ways, by detaching from the bone the tibial origin of the soleas,
123. Saphena Veins, — The subcutaneous veins on the dorsum of the foot
form an arch convex towards the toes (as on the back of the hand), from which
issue the two main subcutaneous trunks of the lower limb, the internal and ex-
ternal saphena veins. The internal saphena vein can be always plainly seen
over the front of the inner ankle. Its farther course up the inner side of the
leg, knee, and thigh to its termination in the femoral is not in all persons mani-
fest.
The external saphena vein runs behind the outer ankle and up the middle of
the calf to empty itself (generally) into the popliteal vein.
THE FOOT.
What are the bony landmarks which guide us in the surgery of the foot ?
124, Points of Bone. — Along the inner side of the foot, beginning from
behind, we can feel — 1, the tuberosity of the os calcis ; 2, the projection of the
internal malleolus; 3, the projection of the os calcis, termed "sustentaculum
tali," about one full inch below the malleolus ; 4, about one inch in front of the
malleous internus, and a little lower, is the tubercle of the scaphoid bone ; the
gap between it and the sustentaculum tali being filled by the calcaneo-scaphoid
ligament and the tendon of the tibialis posticus, in which there is often a sesa-
moid bone; 5, the internal cuneiform bone; 6, the projection of the first meta-
tarsal bone ; 7, the sesamoid bones of the great toe.
Along the outer side of the foot we can feel — 1, the external tuberosity of the
OS calcis ; 2, the external malleolus ; 3, the peroneal tubercle of the os calcis,
one inch below the malleolus, with the long peroneal tendon below it, and the
short one above it ; 4, the projection of the base of the fifth metatarsal bone,
125, Lines of Joints, — In fat persons the following rules for finding the
joints may be of service as regards the surgery of the foot: —
The level of the ankle joint lies about half an inch above the end of the inner
malleolus. This is worth remembering in performing "Syme's" amputation.
The tubercle of the scaphoid bone is the best guide to the astragalo-scaphoid
joint which lies immediately behind it; and the plane of this joint is in the same
line as that of the calcaneo- cuboid. Thus a line drawn transversely over the
dorsum of the foot, behind the tubercle of the scaphoid, would strike both the
joints opened in "Chopart's" operation.
Place your thumb on the tubercle of the scaphoid, and measure about one
inch and a half in front; here you find the joint between the internal cuneiform
bone and the metatarsal bone of the great toe. This point is useful in Lisfranc's
operation, which consists in the removal of the metatarsal bones.
The line of the calcaneo-cuboid joint lies midway between the external
malleolus and the (tarsal) end of the metatarsal bone of the little toe.
The projection of the fifth metatarsal bone is the guide to the joint between
it and the cuboid.
Notice that the line of the joints between the metatarsal bones and the first
phalanges lies a fall inch further back than the interdigital folds of the skin.
This is a point to be remembered in amputating the toes.
126, Dorsal Artery. — The line of the dorsal artery of the foot is from the
middle of the ankle to the interval between the first and second metatarsal
bones. The artery can be felt beating over the bones along the outer side of
the extensor longus pollicis, which is the best guide to it,
127, Bursa. — The synovial sheath of the extensor longus pollicis extends
from the front of the ankle, over the instep (apex of the internal cuneiform
bone) as far as the metatarsal bone of the great toe. There is generally a bursa
over the instep, above, or it may be below, the tendon.
944 LANDMARKS, MEDICAL AND SURGICAL.
There is often a large irregular bursa between the tendons of the extensor
longus digitorum, and the projecting end of the astragalus, over which the
tendons play. There is much friction here. It is well to be aware that this
bursa sometimes communicates with the joint of the head of the astragalus.
128. Plantar Arteries. — The course of the external plantar artery corre-
sponds with a line drawn from the hollow behind the inner ankle obliquely
across the sole nearly to the base of the fifth metatarsal bone ; from thence the
artery turns transversely across the foot, lying (deeply) near the bases of the
metatarsal bones, till it inosculates with the dorsal artery of the foot in the first
interosseous space.
The course of the internal plantar corresponds with a line drawn from the
inner side of the os calcis to the middle of the great toe.
129. Plantar Fascia. — To divide the plantar fascia subcutaneously, the best
place is about one inch in front of its attachment to the os calcis. This is the
narrowest part of it. The knife should be introduced on the inner side ; and
the incision will be behind the plantar artery.
The subcutaneous section of the tendon of the abductor pollicis should be
made about one inch before its insertion.
THE ARM.
130. Clavicle. — The line of the clavicle and the projection of the joint at
either end of it can always be felt, even in the fattest persons. Its direction is
not perfectly horizontal, but slightly inclined downwards, when the arm hangs
quietly by the side. When the body lies flat on the back, the shoulder not only
falls back, but rises a little, the weight of the limb being taken off. Hence the
modern practice of treating fractures of the clavicle (in the early stage) by the
supine position.
On the front surface of the clavicle, not far from its acromial end, there is in
many persons of mature age a spine-like projection of bone. So far as I know,
it has not been described. A gentleman, himself a surgeon, showed me an
instance in his own person. He suspected it was an exostosis.
As a rule the acromio-clavicular joint forms an even plane. But there is
sometimes a knob of bone at the acromial end of the clavicle ; or it may be
only a thickening of the fibro-cartilage, sometimes existing in the joint. In
either case this relief might be mistaken for a dislocation, or even for a fracture.
A reference to the other shoulder might settle the question.
131, Bony Points of the Shoulder. — We can distinctly feel the spine of
the scapula and the acromion, more especially at the angle where they join
behind the shoulder. This angle is the best place from which to measure in
taking the comparative length of the arms.
In some shoulders, though very rarely, there is an abnormal symphysis be-
tween the spine of the scapula and the acromion. There may indeed be two
symphyses and two acromial bones, in which case the acromion has two points
of ossification. Tliose abnormal symphyses might be mistaken for fractures,
until we have examined the opposite shoulder, which is sure to present a simi-
lar conf'onnalioi).'
Tuberosities. — Projecting beyond the acromion (the arm hanging by the
side), we can feel, through the fibres of the deltoid, the upper part of the hume-
rus. It distinctly moves tinder the hand when the arm is rotated. It is not
the head of the bone which is felt, but the tuberosities, the greater externally,
1he lesser in front. These tuberosities form the convexity of the shoulder.
When the arm is raised, this convexity disappears; there is a slight depression
' See Pnigc on " (1ssa Acromialia" (" Zcitpclirifl fur ralionellc McmIIz."), 3. Rcihe Bd. vii. 1859.
THE ARM. 945
in its place. The iiead of tlie bone can be felt bj pressing the fingers bigh up
in the axilla.
The absence of this prominence formed by the upper part of the humerus
under the deltoid, and the presence of a prominence low in the hollow of the
axilla, or in front, below the coracoid process, or behind, on the back of the
scapula, bespeak dislocation of the head of the bone.
In examining obscure injuries about the shoulder, it is worth remembering
that, in the normal relation of the bones, and in every position, the great tube-
rosity faces in the direction of the external condyle. The head of the bone
faces very much in the direction of the internal condyle.
It is worth remembering also that the upper epiphysis of the humerus includes
the tuberosities; and that it does not unite by bone to the shaft, till about the
20th year.
By making deep pressure in front of the shoulder, when the arm is pendent
and supine, we can feel the bicipital groove. It looks directly forwards, and
runs in a line drawn vertically downwards through the middle of the biceps to
its tendon at the elbow. We should be aware of this, lest it should be mistaken
for a fracture.
132. Coraco-acromial Ligament. — Under the anterior fibres of the deltoid,
we can distinctly feel the position and extent of the coraco-acromial ligament.
A knife, passed vertically through the middle of it, goes at once into the
shoulder joint and strikes the bicipital groove with the tendon — a point to be
remembered in excision.
In persons of an athletic build, the triangular form and beautiful structure
of the deltoid become conspicuous when the muscle is in action. The depression
on the outer side of the arm, indicating its insertion, is the place selected for
issues or setons.
The arm being held up by an assistant, the anterior and posterior borders of
the relaxed deltoid admit of being raised so that in amputation at the shoulder
the knife can be introduced beneath the muscle to make the flap.
133. Axilla. — The anterior border of the axilla, formed by the pectoralis
major, follows the line of the fifth rib. In counting the ribs, or in tapping the
chest, it is worth remembering that the first visible digitation of the serratus
magnus is attached to the sixth rib. The angle of the digitation is directed
forwards and corresponds to the upper edge of the rib. The second visible
digitation corresponds to the seventh rib ; the interval between these digitations,
therefore, corresponds to the sixth intercostal space — a convenient place for
tapping the chest, (38.)
In the normal state no glands can be felt in the axilla.
134. Axillary Artery.— When the arm is raised to a right angle, and the
head of the humerus thereby depressed, the axillary artery is plainly felt beating,
and can be perfectly compressed on the inner side of the coraco-brachialis. This
muscle stands out in relief along the humeral side of the axilla, and is the best
guide to the artery. A line drawn along its inner border — that is, down the
middle of the axilla — corresponds with the course of the artery.
The depth and form of the axilla alter in different positions of the arm. In
the arm raised and abducted the axilla becomes nearly flat ; hence this position
is always adopted in operations.
In opening abscesses in the axilla, the incision should be made midway
between the borders, and the point of the knife introduced from above down-
wards.
135. Brachial Artery. — When the arm is extended and supinated, a line
drawn from the deepest part of the middle of the axilla down the inner side of
the biceps to the middle of the bend of the elbow, corresponds with the course of
the brachial artery. The artery can be felt and compressed all the way down;
but nowhere so effectually as midway, where it lies on the tendon of the coraco-
brachialis on the inner side of the humerus. The proper direction to apply the
60
946 LANDMARKS, MEDICAL AND SURGICAL.
pressure is outwards and a little backwards, else tke artery is apt to slip off the
bone.
The musculo-spiral nerve and superior profunda artery wind round the back
of the humerus about its middle, and come to the front of the external condy-
loid ridge. Thus, for full three inches above the condyles, there is nothing to
interfere with operations on the back of the bone, which is here broad and flat.
136. Bend of Elbow. — At the bend of the elbow, the tendon of the biceps
can be plainly felt, as well as the pulsation of the brachial artery close to its
inner side, before dividing into the radial and ulnar.
Cutaneous Veins. — The bend of the elbow in young children and in persons
with fat and round arms presents a semicircular fold of which the curve embraces
the lower part of the biceps ; but in muscular persons we see the distinct boun-
daries of the triangular space formed by the pronator teres on the inner side,
and the supinator longus on the outer. Here can be traced, standing out in
strong relief under the thin white skin, the superficial veins, which, in days
gone by, when bleeding was the fashion, were of such great importance. Their
arrangement, although subject to variety, is 'very much like the branches of
the letter M, the middle of the M being at the middle of the elbow. Of these
branches the median basilic, which runs over the tendon of the biceps, is the
largest and most conspicuous, and is generally selected for venesection ; it crosses
the course of the brachial artery, nothing intervening but the semilunar apo-
neurosis from the tendon of the biceps.
137. Landmarks of Elbow. — It is of great importance to be familiar with
the relative positions of the various bony prominences about the elbow. We
can always feel the internal and external condyles. The internal is the more
prominent of the two, and a trifle higher.
Olecranon. — We can always feel the olecranon. This is somewhat nearer,
to the inner than to the outer condyle. Between the olecranon and the internal
condyle is a deep depression in which lies the ulnar nerve (vulgarly called the
" funny bone").
On the outer side of the olecranon, just below the external condyle, is a pit
in the skin, constant even in fat persons (when the elbow is extended). This
pit is considered one of the beauties of the elbow in a graceful arm ; it is seen in
a child as a pretty little dimple. To the surgeon it is most interesting, as in
this valley behind the supinator longus and the radial extensors of the wrist he
can distinctly feel the head of the radius rolling in pronation and supination of
the arm. It is, therefore, one of the most important landmarks of the elbow,
since it enables us to say whether the head of the radius is in its right place,
and whether it rotates with the shaft.
Can the tubercle of the radius be felt ? Yes, but only on the back of the
forearm in the extreme pronation. Its projection is then distinctly perceptible
just below the place where the head of the bone is felt.
Relations of Olecranon and Condyles. — To examine the relative posi-
tions of the olecranon and condyles in the different motions of the elbow-joint,
place the thumb on one condyle, the tip of the middle finger on the other, and
the tip of the forefinger on the olecranon. In extension, the highest point of
the olecranon is never above the line of the condyles ; indeed, it is just in this
line. With the elbow at right angles the point of the olecranoir is vertically
below the line of the condyles. In extreme flexion the point of the olecranon
lies in front of the line of the condyles.
All these relative positicms would be altered in a dislocation of the ulna, but
not (necessarily) in a fracture of the lower end of the humerus.
Sometimes, though rarely, we meet with a hook-like projection of bone above
the internal condyle. It is called a " supra-condyloid" process ; it can be felt
through the skin, with its concavity downwards, and is a rudiment of the bony
canal which, in many mammalia, transmits the median nerve and ulnar artery.
THE FOREARM AND WRIST. 947
A third origin of tlie pronator teres is always attached to it; this origin covers
the brachial arterj.^
Bursse. — The subcutaneous bursa over the olecranon, if distended, would be
as large as a walnut. A second bursa sometimes exists a little lower down
upon the ulna. There is also a small subcutaneous bursa over each of the con-
dyles.
The vertical extent of the elbow-joint is limited, above by a line drawn from
one condyle to the other ; below by a line corresponding to the lowest part of
the head of the radius.
138. Interosseous Arteries. — About one inch below the head of the radius,
the ulnar artery gives oft' the common interosseous ; and this divides, about
half an inch lower, into the anterior and posterior interosseous. Thus, in ampu-
tating the forearm, say two inches below the head of the radius, four arteries at
least would require ligature.
By flexion of the elbow to the utmost, the circulation through the brachial
artery can be arrested ; but the position is painful, and can be tolerated only for
a short time.
Lymphatic Gland. — There is a small lymphatic gland just above the inner
condyle, in front of the intermuscular septum. It is the first to take alarm in
poisoned wounds of the hand.
THE FOREARM AND WRIST.
139. Ulna. — The edge of the ulna can be felt subcutaneous from the ole-
cranon to the styloid process (in supination). Any irregularity could be easily
detected. The styloid process of the ulna does not descend so low as the styloid
process of the radius, or it would impede the free abduction of the hand. Its
apex is on a level with the radio-carpal joint. The head of the ulna is plainly
felt and seen projecting at the back of the wrist, especially in pronation of the
forearm. It then lies between the tendons of the extensor carpi ulnaris and
extensor minimi digiti. There is often a subcutaneous bursa over it.
140. Hadius. — The upper half of the shaft of the radius is so covered by
muscles that we cannot feel it; the lower half is more accessible to the touch,
especially just above and just below the part where it is crossed by the extensors
of the thumb. Its styloid process is readily felt, and made all the more manifest
by being covered by the first two extensor tendons of the thumb. It descends
lower, and lies more to the front than the corresponding process of the ulna.
The relative positions of these styloid processes can be best examined by placing
the thumb on one and the forefinger on the other.
Feel for the little bony pulley on the back of the radius near the wrist, which
keeps in place the third extensor tendon of the thumb. This and the bone just
above it is the place which we examine for a suspected fracture (termed Colles's)
near the lower end of the radius.
111. Carpus. — Below the styloid process of the radius, just on the inner side
of the extensors of the thumb, we feel the tubercle of the scaphoid bone.
Between the styloid procees and the tubercle is the level of the radio-carpal
joint. A little lower we feel the trapezium.
Just below the ulna on the palm of the hand we feel the pisiform bone ; and,
on the inner side of this, the cuneiform.
There are several transverse furrows on the palmar aspect of the wrist. The
lowest of these, which is slightly convex downwards, corresponds with the upper
edge of the anterior annular ligament and the intercarpal joint. The line of the
' See on tHis subject a monograph, "Canalis Supra-Condyloidens Humeri." By W. Gruber.
Petersburgh, 18.56.
948 LANDMARKS, MEDICAL AND SURGICAL.
radio-carpal joint, as already stated, is on a level with, the apex of the styloid
process of the ulna.
In forcible flexion of the wrist, the tendon of the flexor carpi radialis and
that of the palmaris longus come np in relief. On the outer side of the first-
named tendon we feel the pulse, the radial artery here lying close to the radius.
The tendon of the palmaris longus runs near the middle of the wrist, and
close to its inner border runs the median nerve. In letting out deep-seated
matter near the wrist, the incision should be made close to and parallel with the
inner edge of the radial flexor tendon, so as to avoid injury to the median
nerve.
We can feel the tendon of the flexor carpi ulnaris for some distance above
the wrist. It overlies the ulnar artery, and somewhat masks its pulsation.
142. Pulse. — The "pulse at the wrist" is felt just outside the tendon of the
flexor carpi radialis. In feeling the pulse it should be remembered that, in
some cases, the superficialis volse arises higher and is larger than usual. In
such cases it runs by the side of the radial artery, and gives additional volume
to the pulse. The old writers call it "pulsus duplex." When in doubt, there-
fore, it is well to feel the pulse in each, wrist,
143. Great Carpal Bursa. — The great synovial sheath under the annular
ligament common to the flexor tendons of the fingers and the long flexor of the
thumb, extends, upwards, about an inch and a half above the edge of the liga-
ment, and downwards, as low as the middle of the palm. This general synovial
sheath communicates with the special sheaths of the thumb and the little
finger ; not with that of the index, middle, and ring fingers.
144:, "Tabatiere Anatomique." — On the outer side of the wrist we can
distinctly see and feel, when in action, the three extensor tendons of the thumb.
Between the second and third there is a deep depression, at the root of the
thumb, which the French humorously call the "tabati^re anatomique." In this
depression we can make out — 1, the relief of the superficial radial vein ; 2, the
radial artery, in its passage to the back of the hand ; 8, the upper end of the
metacarpal bone of the thumb.
145. Tendons on back of Wrist. — The relative positions of the several
extensor tendons of the wrist and fingers, as they play in their grooves over the
back of the radius and ulna, can all be 'distinctly traced when the several
muscles are put in action. The length of their synovial sheaths should be
remembered. They vary from one inch and a half to two inches and a half.
The longest of all are those of the extensors of the thumb. When these sheaths
are inflamed and swollen, the motion of the tendons becomes painful and gives
rise to a feeling of crepitus, called "tenalgia crepitans" by some writers. It is
said to be met with sometimes in "pianistes."
146. Lines of Arteries. — The course of the radial artery corresponds witli
a line drawn from the outer border of the tendon of the biceps at the bend of
the elbow down the front of the forearm to the front of the styloid process of
the radius. In the upper third of its course the artery is overlapped by the
supinator longus. To make allowance for this, the incision for the ligature of
the artery in this situation should be made, not precisely in the line of its
course, but rather nearer the middle of the forearm.
The line of the ulnar artery runs from the middle of the bend of the elbow
(slightly curving inwards) to the outer side of the pisiform bone. The radial
and ulnar arteries can, in most cases, be clTcctu ally commanded by pressure well
applied at the wrist, in wounds of the palmar arch.
Before we make incisions along the forearm it is always desirable to ascertain
whether the ulnar artery, which usually runs under the superficial muscles, may
not run abnormally over them ; in which case its pulsations can be felt all down
the forearm.
THE HAND. 949
THE HAND.
147. It is beside the purpose here to examine the question whether the hand
can tell more than the arm, the leg, or any part of the body, about the physical
constitution of its owner, and to what use it has been put. Those who are in-
terested in this subject should read a very elaborate treatise by Carus,^ " On the
Reason and Meaning of the Different Forms of the Hand." Still less would I
indulge curiosity by inquiring whether the professors of chiromancy, relying on
the text " erit signum in manu tua et quasi monumentum ante oculos tuos," can
advance any reasonable pretensions for their assertion that they can read in the
farrows of the palm the future destiny of its master.
148. Furrow in Palm. — The only furrow in the palm useful as a surgical
landmark is that which runs transversely across its lower third, and is well seen
when the fingers are slightly bent. This transverse furrow corresponds pretty
nearly with the metacarpal joints of the fingers, with the upper limit of the
synovial sheaths of the flexor tendons of the fingers (that of the little finger
excepted (143) ) ; also with the splitting of the palmar fascia into its four slips.
The transverse metacarpal ligament lies in the same line with it. Again, a
little below this furrow, the digital arteries bifurcate to run along the opposite
sides of the fingers.
149. Interdigital Folds. — By pressing upon the interdigital folds of skin,
we can feel the transverse ligament of the fingers, which prevents their too wide
separation. The skin of these folds is much thinner on the dorsal than the pal-
mar aspect; hence deep-seated abscesses in the palm very frequently burst on
the back of the hand.
150. Digital Furrows. — Concerning the transverse furrows on the palmar
surface of the fingers, notice that the first furrows, close to the palm, do not cor-
respond with the metacarpal joints. The second and third furrows do corre-
spond with their respective joints.
The slight depression observable between the ball of the thumb and that of
the little finger corresponds with the metacarpal joints. The second and third
furrows do correspond with their respective joints.
151. Palmar Arterial Arches. — In opening abscesses in the palm, it is impor-
tant to bear in mind the position of the large arterial arches which lie beneath
the palmar fascia. The line of the superficial palmar arch crosses the palm
about the junction of the upper with the lower two-thirds — that is, in the line
of the thumb separated widely from the fingers. From this, the digital arteries
run straight between the shafts of the metacarpal bones towards the clefts of
the fingers. Incisions, therefore, to let out pus beneath the palmar fascia may
safely be made in the lower two-thirds of the palm, provided they run in the
direction of the middle line of the fingers. The deep palmar arch lies half an
inch nearer the wrist than the superficial.
152. Digital Arteries. — As the digital arteries run along the sides of the
fingers, the incision to open a thecal abscess should be made strictly in the
middle line. It should be made not over but between the joints, since the
sheath is strongest and thickest over the shafts of the phalanges, and therefore
more likely to produce strangulation of the inclosed tendons.
153. Metacarpal Joint of Thumb. — The joint of the metacarpal bone of
the thumb with the trapezium can be distinctly felt by tracing the dorsal sur-
face of the bone upwards till we come to the prominence which indicates the
joint at the bottom of the " tabati^re anatomique." Supposing, however, there
be much swelling, the knife introduced at the angle between the first and
second metacarpal bones readily finds the joint if the blade be directed out-
wards.
' " Ueber Grund und Bedeutung der verschiedenen Formen der Hand." Stuttgart, 1846.
950 LANDMARKS, MEDICAL AND SURGICAL.
154. Sesamoid Bones. — The sesamoid bones of the thumb can be distinctly
felt. Just above them — that is, nearer to the wrist — lies the joint between the
metacarpal bone and the first phalanx. We should remember the position of
these bones in amputation at this joint. Mutatis miUandis the same observa-
tions apply to the sesamoid bones of the great toe.
The extensor tendon of the last joint of the thumb crosses the apex of the
first interosseous space. Under the tendon, and in the angle between the bones,
we feel the radial artery just before it sinks into the palm.
155. Subcutaneous Veins. — The veins on the back of the hand, and their
arrangement in the form of arches which receive the digital veins, is sufficiently
obvious. The number and arrangement of the arches may vary, but in all
hands it is interesting to notice that the veins from the fingers run up between
the knuckles and are out of harm's way.
156. Interosseous Arteries.— Since the dorsal interosseous arteries, like
the palmar, run along the interosseous space, incisions to let out pus should
always be made along the lines of the metacarpal bones.
157. Digital Bursse. — Small subcutaneous burs» are sometimes developed
over the knuckles and the backs of the joints of the fingers. They often be-
come enlarged and unseemly in persons of a rheumatic or gouty tendency.
158. Knuckles and Digital Joints. — The three rows of projections called
"the knuckles" are formed by the proximal bones of the several joint: thus
the first row is formed by the ends of the metacarpals ; the second by the ends
of the first phalanges and so forth. In amputations of the fingers it is well to
remember that in all cases the line of the joints is a little in advance of the
knuckles, that is, nearer the end of the fingers.
Long and graceful fingers, coupled with thickness and breadth of the sentient
pulp at their ends, and too great arching of the nails, have been regarded ever,
since the days of Hippocrates, as not unlikely indications of a tendency to
pulmonary disease.
PALPATION BY THE RECTUM.
The following report is from Mr. Walsham, one of the Demonstrators of
Anatomy, who having a small hand (somewhat less than seven and a half inches
round), has lately had opportunites, in St. Bartholomew's Hospital, of intro-
ducing it up the rectum, in the living subject, for the purpose of diagnosis: —
" It is possible to introduce the hand (if small) into the rectum ; in many
cases into the sigmoid flexure, and in rare instances into the descending colon.
"Once beyond the sphincter, the hand enters a capacious sac, and the follow-
ing important parts can be felt through its walls: —
"Through the anterior wall the hand first recognizes the prostate, which feels
like a moderately large chestnut. Immediately behind the prostate, the vesi-
cul«3 seminales may be distinguished as two softish masses situated one on either
side of the middle line. Internal to them, the whip-cord-likc feel of the vasa
defcrentia can be readily traced over the bladder to the sides of the pelvis.
"The bladder is easily recognized, when moderately distended, as a soft
flutuating tumor behind the prostate; when empty it cannot be distinguished
from the intestines, Avhich then descend between the rectum and the pubes.
The arch of the pubes can well be defined wlicn the bhidder is empty.
"Through the posterior wall of the bowel the coccyx and sacrum can be felt,
the curve of the sacrum being readily followed by the hand.
"The projecting spine of the ischium on each side of the pelvis is a valuable
landmark. From this point the outlines of the greater and lesser sacro-ischiatic
foramina can be traced by the fingers ; and any new growth, encroaching on the
pelvic (;avity through lhose a})('.r1urcs, could bo easily dotoctcd.
" If the hand be now pushed farther up the gut, the promontory of the sacrum
EXAMINATION PER VAGINAM. 951
is readied ; the pulsation of the iliac vessels becomes manifest, and the course
of the external iliac can be traced along the brim of the pelvis to the crural
arch, the loose attachments of the rectum permitting very free movement in
this direction. The internal iliac artery can also be followed to the upper part
of the great sacro-ischiatic foramen.
"By semi-rotatory movement, and alternately flexing and extending the
fingers, the hand can gradually be insinuated into the commencement of the
sigmoid flexure. In the sigmoid flexure the fingers can explore the whole of
the lower part of the abdomen, the loose attachment of this portion of the gut
permitting the hand to travel freely over the iliac and hypogastric regions.
" The parts that can here be felt are the bifurcation of the aorta, the division
of the common iliac arteries, the iliac fossa, and the crest of the ilium.
" In the female, the uterus in the middle line, and the ovaries on either side,
can be readily distinguished.
"In the introduction of the hand into the rectum, in a patient under chloro-
form, the dilatation of the sphincter ani should be very gradual: first two
fingers, then four, and finally the thumb should be passed. It is necessary to
use considerable force, and unless care be taken, not only the integumentary
edge of the anus, but the sphincter itself, may be lacerated. The introduction
is facilitated by the application of the other hand upon the abdomen.
"When the dilatation has been gradual and the hand not too large, no incon-
tinence of feces and no very considerable amount of pain has resulted,
"Dr. G. Simon, in a paper in the 'Archiv fur Clinische Chirurgie,'^ states that
repeated dilatation of the anus to its maximum does not destroy its contractile
power; that he has often made as many as five examinations of the same
rectum ; that in clinical cases he has always permitted one or two of those
present to repeat the examination, and that in no instance has permanent incon-
tinence of feces been the result.
"We have, however, been informed on reliable authority that permanent
incontinence of feces has occasionally followed these repeated examinations.
"What sized hand can be introduced with safety ? Dr. Simon states that it
ought not to exceed nine inches in circumference."
Lastly, we think it right to insist upon the important fact that, in some sub-
jects, even a small hand cannot be passed up the rectum beyond the reflection
of the peritoneum over the second part of the gut. In such instances the peri-
toneum offers a resistance like a tight garter, and prevents the further advance
of the hand without great risk of laceration of the parts.^
EXAMINATION PER VAGINAM.
For this report I am indebted to Dr. Godson, Assistant Physician- Accoucheur,
St. Bartholomew's Hospital: —
" The finger introduced into the vagina comes upon the carunculse myrti-
formes, which are vascular membranous processes independent of the hymen,
variable in number, size, and form. It also feels the transverse ridges known
as 'rugge.'
"Along the anterior wall of the vagina the finger readily detects the track
of the urethra, which feels like a prominent cord and forms an excellent guide
to ^the orifice of the meatus urinarius in passing a catheter. This orifice is
indicated by a slight semicircular prominence, situated about one- third of an
inch above the orifice of the vagina. Behind the urethra the finger comes
upon the posterior wall of the bladder. But the bladder is not perceptible, as
• Yol. XV. p. 1, 1872.
2 For further information on this subject, see a paper by Mr. Walshani, in St. Bartholomew's
Hospital Reports, vol. xii.
952 LANDMARKS, MEDICAL AND SURGICAL.
such, to the touch unless distended. With a catheter previously introduced it
is much more readilj explored.
"The septum between the vagina and the rectum is so thin that, should the
rectum contain fecal matter, its presence becomes at once apparent to the finger.
" The cervix uteri is felt protruding from the roof of the vagina in a direction
downwards and backwards — that is, in a line from the umbilicus' to the coccyx.
The OS uteri is felt, small and round, in the centre of the cervix. The posterior
lip feels a little lower than the anterior. The cul-de-sac formed by the vagina
in front and behind the cervix should be perfectly elastic to the touch, and not
communicate the sensation of a resisting body. Any resistance here bespeaks
an abnormal condition.
"The bony landmarks within reach of a finger, or perhaps two, in a woman
who has not borne a child, are the symphysis pubis, the rami of the pubes and
ischia. The coccyx and part of the hollow of the sacrum may also be felt, but
not without exerting much pressure on the posterior wall of the vagina, which
gives considerable pain. If the promontory of the sacrum can be felt, it is a
sign that the conjugate diameter of the pelvis is abnormal.
"The finger in the rectum can detect almost everything which has been
mentioned in connection with the vagina. The shape and direction of the
cervix uteri are almost as perceptible, and the posterior wall of the uterus can
be examined. The peritoneal fold termed recto-vaginal (Douglas's space) can
also be well explored, and anything abnormal detected in this direction — a point
of great importance in the diagnosis of diseases and displacements of the uterus.
"The ovary in its normal state and position cannot be detected by the touch
even with the hand firmly pressed on the hypogastrium. If a movable body
be felt through the vaginal roof on one side of the cervix, if this body be ex-
quisitely tender and recede at once from the finger, it is an ovary in a state of
prolapse.
" The fundus of a healthy unimpregnated uterus never rises above the level
of the brim of the pelvis, and cannot therefore be felt by pressing the hand on
the hypogastrium.
"The direction of the uterus is subject to changes which cannot be looked
•upon as abnormal. The fundus may be thrown backwards by a distended
bladder, or forwards by a distended rectum. The axis of its cavity is not a
straight but a curved line; and uterine sounds should be shaped to suit it."
INDEX/
Abdomen,- 761
apertures in, 762
boundaries of, 762
landmarks of, 928
lymphatics of, 596
manipulation of, 931
muscles of, 385
regions of, 762
viscera of, 763, 931
Abdominal lines, 928
Absorbent glands. See Lym-
phatic Glands.
Absorbents. See Lymphatics.
Acervulus cerebri, 630
Acetabulum, 250
Acromion, 221
Actions of muscles. See each
group of muscles.
Adipose tissue, 41
Air-cells, 833
Air-sacs of lung, 833
Air- tubes, 823
Alse of nose, 711
of A^omer, 185
Alimentary canal, 745
development of, 120
subdivisions of, 745
See also Stomach, Intes-
tines, etc.
Allantols, 102, 850
Alveoli, formation of, 754
of lower jaw, 187
of lung, 833
of stomach, 770
of upper jaw, 178
Amnion, 101
false, 102
Amcfiboid motion, 38
Amphiarthrosis, 281
AmpuUiB of semicu'cular canals,
739
of tubull lactiferi, 877
Amygdala3, 756
of cerebellum, • 633
Anastomosis of arteries, 4G3
around elbow, 514
Andersch, ganglion of, 659
Anatomy, descriptive, 131
general, 33
surgical. See Surgical Anat-
omy.
Aneurism of aorta, etc. See
Aorta, etc.
Angle of jaw, etc. See indi-
vidual bones.
Ankle-joint, 331
landmarks of, 941
relations of tendons and ves-
sels, 333
Annulus ovalis, 804
Antihelix, 729
fossa of, 729
Antitragus, 729
Antrum of Highmore, 177
landmarks of, 918
Anus, 896
development of, 120
landmarks of, 935
muscles of, 896
Aorta, 464
development of, 117
division of, 930
landmarks of, 930
sinuses of, 465
abdominal, 525
branches of, 526
surgical anatomy of, 525
arch of, 464
ascending part of, 465
branches of, 468
descending part of, 467
peculiarities of, 468
of branches of, 468
svirgical anatomy of, 467
transverse portion of, 466
descending, 522
primitive, 117
thoracic, 522
branches of, 523
surgical anatomy of, 522
Aperturas scala; vestibuli, 739
Aperture. See Openings, Ori-
fice, etc.
Aponeurosis, 340
of deltoid, 404
of external oblique, in ingui-
nal region, 879
infraspinous, 405
of insertion, 341
of investment, 341
of occipito-frontalis, 344
pharyngeal, 760
of soft palate, 368
subscapular, 404
suprahyoid, 362
supraspinous, 405
Aponeurosis —
vertebral, 378
Apophysis, 54, 56, 132
Apparatus Hgamentosus coUi.
292
Appendages of eye, 725
of skin, 87
of uterus, 872
Appendices epiploica3, 767, 781
Appendix auriculae, 802, 806
enslform, 209
vermiformis, 778
xiphoid, 209
Aqua labyrinthi, 743
Aquaaductus cochlea, 163, 740
Fallopii, 164, 734
Sylvii, 636
vestibuli, 163, 738
Aqueous chamber, 723
humor, 722
chambers of, 723
secretingmembrane of, 723
Arachnoid membrane of brain,
608
of cord, 603
cavity of, 603
Arantius, body of, 805
nodules of, 805
ventricle of, 612
Arbor vitae of cerebellum, 634
uterinus, 872
Arch of aorta. See Aorta, arch
of.
of colon, 779
cortical, 840
crural, 880, 890
landmarks of, 931, 936
deep, 891
femoral, 880, 890
nasal, 201, 565
palmar, deep, 515
landmarks of, 949
superficial, 519
pharyngeal, 109
plantar, 562
of pubes, 249, 253
supraorbital, 156, 157
of vertebra, 132
zygomatic, 199
Arches, aortic (foetal), 117
of palate, 756
pharyngeal, 109
* Each Artery, Canal, Lig-ament, Muscle, Nerve, etc., is placed in the Index under the head of Artery,
Muscle, Nerve, etc. ; Carotid artery, for example, being found under Artery, carotid ; Median nerve,
under Nerve, median, etc.
( 953 )
954
INDEX.
Arciform fibres, 611, 613
Area, germinal, 98
vascular, 101
Areola of breast, 877
Areolar tissue, 39
Arm, arteries of, 507
bones of, 223
fascia of, 407
landmarks of, 944
lymphatic glands of, 593
lymphatics of, 594
muscles of, 407
nerves of, 6 71
veins of, 573
Arnold's ganglion, 656
nerve, 661
Arteria or Arteria;. See Ar-
tery.
Arteria3 proprise renales, 845
receptaculi, 492
Artei-iolse recta3 of kidney, 845
Ai'tery or Arteries —
anastomoses of, 463
capillary, 78, 463
development of, 117
distribution of, 463
general anatomy of, 75
mode of division of, 463
of origin of branches of, 463
nerves of, 77
sheath of, 73
structure of, 75
subdivision of, 463
systemic, 463
vessels of, 77
accessory pudic, 540
acromial thoracic, 509
alar thoracic, 510
alveolar, 485
anastomotica magna of bra-
chial, 514
of femoral, 552
angular, 480
anterior auricular, &c. See
Artery, auricular, &c.
aorta. See Aorta,
articular, of knee, 554
ascending cervical, 503
pharyngeal, 481
auricular, 481
anterior, 482
posterior, 481
axillary, 507
branches of, 509
landmarks of, 945
peculiarities of, 508
surgical anatomy of, 508
azygos articular of knee, 555
basilar, 502
brachial, 511
IjranchcH of, 514
lamliiiarks of, 945
])(;cii]iariti('S of, 51 2
surgical anatomy of, 513
bronchial, 523, 834
buccal, 4 85
of l)ulb of urctlirn, 511, 901
cal(^•lIK!an, inti:rnal, 561
carotiil, 4 71
common, 471
Artery or Arteries — •
peculiarities of, 473
surgical anatomy of, 474
external, 475
surgical anatomy of, 475
internal, 489
surgical anatomy of, 491
carpal of radial, 517
of ulnar, 521
posterior of radial, 517
of ulnar, 521
of cavernous body, 542, 858
centralis modioli, 740
retinaj, 495, 722
cerebellar, 501, 502
cerebral, 495, 502
cervical, ascending, 503
deep, 505
superficial, 504
choroid, anterior, 495
posterior, 502
ciliary, 493, 725
anterior, 494, 725
long, 494, 725
short, 493, 725
circle of Willis, 502
cu'cumflex of arm, 510
iliac, 546
superficial, 550, 878
of thigh, external, 551
internal, 551
cochlear, 744
coccygeal, 543
coeliac axis, 526
colica dextra, 531
media, 531
sinistra, 531
comes nervi ischiadici, 543
phrenici, 504
communicating, anterior, of
brain, 495
posterior of brain, 495
communicating branch of
dorsalis pedis, 559
of ulnar, 521
coronaria vcntriculi, 527
coronary, of heart, 469
inferior, 479
left, 469
of Hp, upper, 480
of lip, lower, 479
right, 469
superior, 480
of corpus cavcrnosum, 542
cremasteric, 545, 861
crico-thyroid, 476
cystic, 529
deep branch of ulnar, 521
cervical, 505
palmar arch, 515
temporal, 485
deferent, 533
dental, infi'rior, 484
supei'ior, 485
d('sc(!nding ])alatine, 486
digital, of ])laiitar, 562
of ulnar, 521
landniai'ks oi", 949
dorsal, of liinihar, 533
of ])enis, 512
See also Artery, dorsalis.
Artery or Arteries —
dorsalis hallucis, 559
indicis, 518
linguEe, 477
pedis, 557
branches of, 558
landmarks of, 943
peculiarities of, 558
surgical anatomy of, 558
penis, 542
pollicis, 517
scapulae, 510
epigastric, 545, 892
landmarks of, 931
peculiarities of, 546
relation of, to external
ring, 892
to internal ring, 883
superior, 504
superficial, 550, 878
ethmoidal, 493
external carotid, &c. See
Artery, carotid, &c.
facial, 477
landmarks of, 916
peculiarities of, 480
surgical anatomy of, 480
transverse, 482
femoral, 546
branches of, 550
compression of, 938
landmarks of, 938
peculiarities of, 548
surgical anatomy of, 548
deep, 550
frontal, 493
gastric, 527, 529
gastro-duodenalis, 528
gastro-epiploica dextra, 528
sinistra, 529
gluteal, 543
inferior, 543
landmarks of, 939
helicine, 859
hemorrhoidal, external, 541
inferior, 541
middle, 539
superior, 531
hepatic, 527, 786, 789
hyaloid, 113
hyoid branch of lingual, 477
of superior thyroid, 476
hypogastric, in foitus, 53 7,
812, 813
ileo-colic, 530
iliac, 535, 543
circumfiex, 546
common, 535
peculiarities of, 535
surgical anatomy of, 536
external, 544
surgical anatomy of, 544
int(M-nal, 53 7
at birth, 537
peculiarities of, 538
in i'oitus, 5;>7
surgical anatomy of, 538
ilio-lumbar, 543
inierior cerebellar, coronary,
&c. See Artei-y, cerebel-
lar, coronary, &c.
INDEX.
955
Artery or Arteries^ —
infraorbital, 485
innominate, 470
peculiarities of, 470
surgical anatomy of, 470
intercostal, 504, 505, 523
anterior, 504, 523
dorsal, 524
superior, 504
interlobular of kidney, 845
internal auditory, calcanean,
&c. See Artery, auditory,
calcanean, &c.
interosseous of ulnar, 520
landmarks of, 947
dorsal of foot, 558
of hand, 517
landmarks of, 950
of radial, 517
labial, inferior, 479
lachrymal, 492
laryngeal, 503
inferior, 476
superior, 476
lateral sacral, 543
sjjinal, 501
lateralis nasi, 480
lingual, 477
lumbar, 533, 543
malleolar, 556
mammary, landmarks of, 923
internal, 504
masseteric, 485
maxillary, internal, 483
median of forearm, 520
of spinal cord, 501
mediastinal, 504
posterior, 523
meningeal, from ascending
pharj-ngeal, 482
anterior, from carotid, 492
inferior, from occipital, 481
middle, from internal max-
illary, 484
landmarks of, 915
posterior, from vertebral,
501
small, from internal maxil-
lary, 484
mesenteric, inferior, 531
superior, 529
metacarpal, 517
metatarsal, 558
middle cerebral, 495
sacral, 534
musculo-phrenic, 504
mylo-hyoid, 485
nasal, 486
of nasal fossae, 713
of ophthalmic, 493
of septum, 480
nutrient of femur, 545
of fibula, 661
of humerus, 514
of radius, 520
of tibia, 561
of ulna, 520
obturator, 539
external, 540
internal, 540
peculiarities of, 540
Artery or Arteries —
relations of, in hernia, 893
occipital, 480
oesophageal, 503, 523
omphalomesenteric, 117
ophthalmic, 492
orbital, 485
ovarian, 533, 872
palatine, ascending, 479
descending, 486
inferior, 479
of pharyngeal, 486
posterior, 486
palmar arch, deep, 515
superficial, 519
interosseas, 518
palpebral, 493
pancreatic, 529
pancreatica magna, 529
pancreaticse parvaj, 529
pancreatico-duodenalis, 528
inferior, 530
perforating arteries, from
mammary artery, 504
from plantar, 562
from profunda, 551
from radial, 518
pericardiac, 504, 523
perineal, superficial, 541
transverse, 541
peroneal, 660
anterior, 561
pharyngeal, ascending, 481
phrenic, 533
superior, 504
plantar external, 561
internal, 661
landmarks of, 944
popliteal, 552, 553
branches of, 554
landmarks of, 940, 942
peculiarities of, 553
surgical anatomy of, 553
posterior auricular, carpal,
&c. See Artery, auricular,
carpal, &c.
princeps cervicis, 481
poUicis, 518
profunda of arm, inferior, 614
superior, 514
cervicis, 504
femoris, 650
pterygoid, 485
pterygo-palatine, 486
pubic, 645
pudic, accessory, 540
external, 550
deep, 550
inferior, 550
landmarks of, 939
superficial, 550, 878
superior, 550
internal, 540
peculiarities of, 540
in female, 542
pulmonary, 563, 804, 833
pyloric, 627
radial, 615
branches of, 617
landmarks of, 948
peculiarities ®f, 516
Artery or Arteries —
surgical anatomy of, 516
radialis indicis, 518
ranine, 477
recurrent interosseous, 520
radial, 517
tibial, 656
ulnar, 620
renal, 532, 843
sacra media, 634
sacral, lateral, 543
middle, 634
scapular, posterior, 504
sciatic, 542
sigmoid, 531
spermatic, 532, 861
spheno-palatine, 486
spinal, anterior, 501
from intercostal, 524
lateral, 501
in loins, 543
from lumbar, 533
median, 501
in neck, 601
posterior, 501
in thorax, 223
from vertebral, 501
splenic, 529, 797
sterno-mastoid, 476
stylo-mastoid, 481
subclavian, 496
branches of, 500
landmarks of, 922
left, 497
pewiliarities of, 498
right, 496
surgical anatomy of. 498
sublingual, 477
submaxillary, 479
submental, 479
subscapular, 510
superficialis vola;, 517
superior cerebellar, coronary,
&c. See Ai'tery, cerebel-
lar, coronary, &c.
supraorbital, 493
supi'arenal, 532
suprascapular, 503
sural, 654
tarsal, 558
temporal, 482
anterior, 482
deep, 485
landmarks of, 916
middle, 482
posterior, 482
surgical anatomy of, 482
thoracic, acromial, 509
alar, 510
long, 509
superior, 509
thoracic aorta, 522
of thyroid gland, 835
thyroid, inferior, 502
middle, 470
superior, 476
surgical anatomy of, 476
thyroid axis, 502
tibial, anterior, 655
branches of, 556
landmarks of, 942
956
INDEX.
Artery or Arteries —
peculiiirities of, 556
surgical anatomy of, 556
posterior, 559
branches of, 560
landmarks of, 942
peculiarities of, 559
surgical anatomy of, 560
recurrent, 556
tonsillar, 479, 503
tracheal, 503
transverse of basilar, 502
facial, 482
transversalis colli, 503
tympanic, from internal caro-
tid, 491
from internal maxillary, 483
ulnar, 618
branches of, 520
landmarks of, 948
peculiarities of, 519
relations of, 519
surgical anatomy of, 520
recurrent, anterior, 520
posterior, 520
umbilical in foetus, 812, 813
uterine, 539, 872
vaginal, 539
of vas deferens, 539
vasa aberrantia of arm, 512
brevia, 529
intestini tenuis, 530
vertebral, 500
primitive, 117
vesical, inferior, 539
middle, 539
superior, 538
vestibular, 744
vidian, 486
Arteriola} rectaj, 845
Arthrodia, 281
Articulations, 279
acromio-clavicular, 306
ankle, 331
astragalo-calcanean, 334
astragal o-scaphoid, 334
atlo-axoid, 288
calcaneo-astragaloid, 334
calcaneo-cuboid, 335
calcaneo-scaphoid, 336
carpal, 316
carpo-mctacarpal, 319
chondral, 299
classification of, 280
coccygeal, 302
costo-chivicuiar, 305
costo-stcrnal, 297
costo-traiisverse, 296
costo-vertebral, 295
elbow, 310
f(:i)iorr>tii)ial, 325
of loot, 331
hand, 31 G
liip, 322
iiiunovable, 280
intercliondral, 299
knee, 325
larynx, 810
lower extremity, 322
metacarpal, 321
metacarpo-j)lialung('al, 3 21
Articulations —
metatarsal, 338
metatarso-phalangeal, 338
mixed, 281
movable, 281
movements of, 284
occipito-atloid, 291
occipito-axoid, 292
of pelvis, 300
with spine, 299
phalanges, 322, 338
pubic, 303
radio-carpal, 815
radio-ulnar, inferior, 314
middle, 313
superior, 313
sacro-coccygeal, 302
sacro-iliac, 300
sacro-sciatic, 301
sacro- vertebral, 299
scapulo-clavicular, 306
scapulo-humeral, 308
slioulder, 308
of spine with cranium, 291
stern o-clavicular, 304
landmarks of, 921
of sternum, 299
tarsal, 334
tarso-metatarsal, 339
temporo-maxillary, 292
tibio-libular, inferior, 331
middle, 331
superior, 330
of the trunk, 285
of tympanic bones, 736
of upper extremity, 304
of vertebral column, 285
wrist, 315
Arytenoid cartilage, 815
Astragalus, 270
Atlas, 134
development of, 141
Atrabiliary capsules, 847
Auricleof ear, 729. /See Pinna,
of heart, 801, 802
appendix of, 802, 806
left, 806
openings in, 803, 806
right, 802
septum of, 802, 806
sinus of, 802, 806
valves in, 803, 805
Axes of pelvis, 254
Axilla, 505
dissection of, 398
landmarks of, 945
surgical anatomy of, 505
Axis, 135
dev(dopment of, 141
central, of cocldea, 739
cerebro-spinal, 602
cctliac, 526
thyroid, 502
Axis-cylinder of nerve tubes, 62
IjACK, furrows of, 926
landmarks of, 926
muscles of, 3 73
JJall and socket joint. -See ]'>n-
arli.rodia.
IJaiid, i'liiiowed, 033
Bartholine, duct of, 759
gland of, 868
Basement membrane, 93
Bauhin, valve of, 778
Beale's researches on the liver,
788
on motor nerves, 73
Beaunis and Bouchard, table of
development, 129
Bertini, column of, 840
Bicuspid teeth, 748
Bioplasm, 38
Bladder, 849
arteries of, 852
base of, 850
body of, 850
cervix of, 850
female, 869
relations of, 869
fundus of, 850
interior of, 852
landmarks of, 934
ligaments of, 850, 907
lymphatics of, 598, 853
muscles of, 851
neck of, 850
nerves of, 853
structure of, 851
summit of, 850
trigone of, 852
uvula of, 852
veins of, 853
Blastema, 38, 752
Blastoderm, 96
Blastodermic membrane, 96
Blood, 83
cumulation of, in adult, 805
in foetus, 812
corpuscles, 33
development of, 117
crystals, 36
disks, 33
gases of, 85
general anatomy of, 33
globules, 33
Bochdalck, ganglion of, 653
on triticeo-glossus, 821
Body, growth of, 94
Malpighian, 840, 841
of tooth, 747
of vertebra, 133
Bone, animal constituent of, 50
apophyses of, 56
articular lamella of, 279
canaliculi of, 49
cancellous tissue of, 46
cells, 48
chemical analysis oi", 50
compact tissue of, 46
descriptive anatomy of, 131
development ol", 51
diploe of, 131
ejiriliy constituent of, 50
eminences and depressions of,
132
epiphyses of, 55
general anatomy of, 46
growth of, 54
llaversian canals of, 48
systems of, 4 9
spaces ol', 49
INDEX.
957
Bone —
inorganic constituent of, 50
lacunas of, 49
lamellae of, 49
lymphatics of, 48
marrow of, 47
medullary canal of, 47
membrane of, 47
microscopic sti-ucture of, 48
nerves of, 48
number of, 131
organic constituent of, 50
ossification of, 51
ossific centres, number of, 55
perforating fibres of, 49
periosteum of, 47
spongy tissue of, 4G
structure of, 46
vessels of, 47
astragalus, 270
atlas, 134
axis, 135
calcaneum, 267
carpal, 235
clavicle, 215
coccyx, 146
cranial, 149
cuboid, 269
cuneiform of carpus, 236
of tarsus, 272
ear, 735
etlimoid, 170
facial, 149, 174
femur, 254
fibula, 265
foot, 26 7
frontal, 156
hand, 235
humerus, 223
hyoid, 206
ilium, 246
incus, 735
innominate, 245
ischium, 246, 248
lachrymal, 179
lesser lachrymal, 180
lingual, 206
magnum, 240
malar, 180
malleus, 735
maxillary, inferior, 186
superior, 175
metacarpal, 241
metatarsal, 274
nasal, 174
navicular, 236, 272
occipital, 150
orbicular,
palate, 182
parietal, 154
patella, 2C0
pelvic, 251
phalanges of foot, 275
of hand, 243
pisiform, 238
pubic, 246
radius, 233
ribs, 210
sacrum. 143
scaphoid of carpus, 236
Bone —
of tarsus, 272
scapula, 218
semilunar, 236
sesamoid, 276
sphenoid, 165
spenoidal spongy, 169
stapes, 736
sternum, 207
supernumerary, 173
tarsal, 2G7
temporal, 159
tibia, 262
trapezium, 238
trapezoid, 239
triquetral, 173
turbinated, inferior, 184
middle, 171
superior, 171
tympanic, 732
ulna, 228
unciform, 240
unguis, 179
vertebra dentata, 136
prominens, 136
vertebrffi, cervical, 133
coccygeal, 142
dorsal, 13 7
lumbar, 139
sacral, 142
vomer, 185
■wormian, 173
Bowman on structure of kid-
ney, 841
Brachia of optic lobes, 631
Brain, 61, 606, 609. See also
Cerebrum.
arachnoid of, 608
base of, 619
development of, 110
dura mater of, 606
interior of, 622
lateral ventricles of, 624
landmarks of, 915
levels of, 915
lobes of, 618
membranes of, 606
subdivision into parts, 609
upper surface of, 615
weight of, 610
Breasts, 876
Bridge of nose, 174
Brim of pelvis.
Bronchi, 823
mode of subdivision in lung,
831
septum of, 823
structure of, in lobules of
lung, 831
Brunner's glands, 775
Bubonocele, 885
Bulb, artery of, 541, 901
of corpus cavern osum, 857
of corpus spongiosum, 858
olfactory, 638
Bulbi vestibuli, 869
Bulbs of fornix, 621, 628
Burns, ligament of, 889
Burs£E, carpal, 948
digital, 950
gluteal, 440
Burs£E —
mucosEe, 280
of ham, 553
of olecranon, 947
patellar, 940
plantar, 943
popliteal, 940
of shoulder, 308
synovial, 280
of wrist, 948
Buttocks, folds of, 939
landmarks of, 938
C^CUM, 777
Calamus scriptorius, 612
Calcaneum, 267
Calices of kidney, 839, 846
Callender on hernia, 889
Camper, ligament of, 900
Canal or Canals —
accessory palatine, 182
alimentary, 745
for Arnold's nerve, 164
auditory, 731
carotid, 162, 163
central of modiolus, 740
for chorda tyrapani, 161, 738
of cholera, 740
crural, 891
dental, anterior, 176
inferior, 188
posterior, 1 7 6
ethmoidal, 158
femoral, 891
of Fontana, 718
Haversian, of bone, 48
of Huguicr, 161, 645, 733
of Hunter, 547
landmarks of, 938
incisive, 197
incisor, 178
infraorbital, 175, 176
inguinal, 882
landmarks of, 931
for Jacobson's nerve, 163
lachrymal, 176, 180, 728
malar, 181
medullary, 110
nasal, 174
naso-palatine, 185
of Kuck, 866, 876
palatine, accessory, 181, 19 7
anterior, 178, 197
posterior, 176, 177, 197
of Petit, 724
portal, 785
pterygoid, 167
pterygo-palatine, 167
sacral, 145
semicircular 739. See Semi-
circidar canals.
spermatic, 882
spinal, 149
of spinal cord, 68, 110
spiral, of cochlea, 740
of modiolus, 740
temporo-malar, 181
for tensor tympani, 164, 734
vertebral, 149
Vidian, 168
of "VVirsung, 793
958
INDEX.
Canalicull of bone, 49
of eyelids, 7 28
Canalis cochlea^, 741
membranacea, 741
reuniens, 742
spiralis modioli, 740
Cancellous tissue, 46
Cantlii of eyelids, 725
Capillaries, 78
pulmonary, 833
Capsular ligament. See Ligar-
ment.
Capsule, atrabiliary, 847
of Glisson, 786
of lens, 723
in foetus, 113, 723
of Malpighian bodies of kid-
ney, 840, 841
supra-renal, 847
Caput cornu posterius, 66
gallinaginis, 853
Cardia of stomaeh, 76 7
Carpus, 235
articulations of, 316
development of, 244
landmarks of, 947
Cartilage or Cartilages, 43
articular, 44
arytenoid, 815
of aui'icle, 729
of bronchi, 823, 832
calcifications of, 51
cells of, 43
cellular, 43
circumferential, 46
connecting, 45
costal, 44, 214
cricoid, 815, 930
cuneiform, 816
of ear, 729
ensiform, 209
of epiglottis, 816
fibro-, 45. See Fibro-cartl-
lage.
general anatomy of, 43
hyaline, 44
interarticular, 45
intercellular substance of,
44
interosseous, 44
of knee, 328
of larynx, 814
of nose, 711
of pinna, 729
palpebral, 726
permanent, 43
reticular, 46
of Santorini, 816
semilunar of knee, 328
of septum of nose, 711
sesamoid, 259, 711
spongy, 44
stratiform, 46
structure of, 43
tarsal, 726
temporary, '1.'!, 44
tliyroid, 814
of tracl)(!ri, 823
of Wrisbcrg, 816
xiphoid, 209
yellow, 46
Cartilagines minores of nose,
711
Cartilago triticea, 817
Caruncle, lachrymal, 727
Caruncula lacrymalis, 727
mammlllaris, 638
Carunculaa myrtiformes, 868
Casserian ganglion, 648
Cauda equina, 603, 689
Catheter, rules for introducinc,
936
Cava, vena. See Vena cava.
Cavernous body, 857
artery of, 542, 858
Cavities of reserve of teeth, 755
Cavity, central of lateral ven-
tricle, 625
cotyloid, 250
digital of fifth ventricle, 625
of lateral ventricle, 625
glenoid, 160, 222
of larynx, 818
of pelvis, 253
sigmoid, 230, 234
Cells, 38
of bone, 48
cleavage of, 94
of Corti, 742
of Deiters, 742
differentiation of, 94
ethmoidal, 158, 171
giant, 54
hearing, 73
hepatic, 787
mastoid, 161, 734
myeloid, 54
of nerves, 61
olfactory, 73
segmentation of, 94
sight, 73
sphenoidal, 166
taste, 73
wandering, 41
Cellular tissue, 39
lymphoid, 41
mucoid, 41
retiform, 41
Cement of teeth, 751, 753
formation of, 751, 753
Centres of ossification, 51
Centrum ovale majus, 623
minus, 622
Cerebelli incisura anterior, 632
posterior, 632
Cerebellum, 610, 632
commissures of, 632, 633
corpus dentatum of, 634
fissures of, 634
ganglion of, 635
hemispheres of, 632
laminiE of, 632
lobes of, 634. See Lobes.
lobulus centralis of, 634
peduncles of, 635
slruf;ture of, 634
v.dle.y of, 633
ventricle of, 635
weight of, 632
Cer<!bro-spinal axis, 604
fluid, 609
Cerebrum, 609
Cerebrum —
base of, 615, 619
commissures of, 630
convolutions of, 615
crura of, 628
fibres of, 631
fissures of, 619
general arrangement of, 622
gray matter of, 616
hemispheres of, 615
interior of, 622
labia of, 622
lobes of, 616
middle, 616, 619
frontal, 616, 619
occipital, 616
parietal, 616
temporo-sphenoidal, 616
peduncles of, 621
structure of, 63^
sulci of, 615
under surface of, 615, 619
upper surface of, 615
ventricles of, 624, 630
weight of, 610
Cervix cornu, 66
of penis, 856
uteri, 871
Chambers of eye, 722
Cheeks, muscles of, 746
structure of, 746
Chest, landmarks of, 922
muscles of, 399
Chiasma of optic nerve, 639
Chondrine, 46
Chorda dorsalis, 98, 106
tympani, 644, 738
ChordtB tcndinesE of left ven-
tricle, 805
of right, 805
vocales, 819
Willisii, 571
Chorion, 96, 102
shaggy, 103
Choroid coat of eye, 716, 717
plexus of fourth ventricle,
636
of lateral ventricle, 625
of third ventricle, 629
Chyle, 37
vessels, 774
Chyli reccptaculum, 589
Chyliferous vessels, 588
Cilia, 727
Ciliary processes, 718
Circle of AVillis, 502
Circulation of blood in adults,
805
in foetus, 812
Circumduction, 284
Cistern of I'ecquet, 589
Clarke, Lockhart, researches on
brain and spinal cord, 65
on cranial nerves, 663
Clavicle, 215
articulations of, 218
attachments of muscles to,
218
development of, 218
fi-acturc of. See Fracture.
landmarks of, 923, 944
INDEX
959
ClaTicle —
peculiarities of, 218
Cleavage of cells, 94
Clitoris, 868
frajnum of, 868
lymphatics of, 598
muscles of, 868, 900
prepuce of, 868
Cloacal cavity, 126
Club-foot, 453
Coccyx, 146
articulations of, 147
attacliment of muscles to, 147
development of, 147
Cochlea, 789
arteries of, 740, 744
central axis of, 739
cupola of, 739
denticulate lamina of, 741
hamular process of, 741
infundibulum of, 739
lamina spiralis of, 739
membranous zone of, 740
modiolus of, 739
nerves of, 744
osseous zone of, 740
scala tympani of, 741
vestibuli of, 741
spiral canal of, 740
veins of, 744
Collateral circulation. See Sur-
gical Anatomy of each
artery.
Collecting tubes of kidney, 842
CoUes's fracture, 428
Colon, 779
ascending, 779
descending, 779
sigmoid flexure of, 779
transverse, 779
Colotomy, landmarks for, 933
Columella cochlete, 739
Column of Bertini, 840
cortical, of kidney, 840
posterior vesicular of spinal
cord, 66
Columna nasi, 710
Columnas carnese of left ventri-
cle, 808
of right ventricle, 805
papillares, 805, 808
Columns of abdominal ring, 880
of medulla oblongata, 610
of spinal cord, 605
of vagina, 871
Comes nervi ischiadic!, 543
phrenici, 604
Commissura brevis of cerebel-
lum, 633
simplex of cerebellum, 632
Commissure of flocculus, 633
optic, 166, 621, 639
Commissures of brain, anterior,
630
middle, 630
posterior, 630
soft, 630
of spinal cord, gray, 606
white, 606
Compact tissue of bone, 46
Conarium, 630
Concha, 729
Condyles of humerus, 227
landmarks of, 946
Cone-granules of retina, 721
Coni vasculosi, 863
Conjunctiva, 727
Connective tissue, 89
Conus arteriosus, 804
Convolution, ascending parietal,
617
angular, 617
of corpus callosum, 616
of longitudinal fissure, 616
supraorbital, 616
Convolutions of cerebrum, an-
nectant, 618, 619
cortical substance of, 615
structure of, 64, 615
white matter of, 615
Cord, genital, 126
spermatic. See Spermatic
cord,
spinal. See Spinal cord,
umbilical, 104
Cords, vocal, 818, 819
Corium, 84, 92, 752
Cornea, 715
arteries and nerves of, 716
elastic laminae of, 715
proper substance of, 715
structure of, 715
Cornicula laryngis, 816
Cornu Ammonis, 627
C or nua of coccyx, 147
of fascia lata, 889
ofhyoidbone, 206
of lateral ventricle, 625, 626
of sacrum, 144
of thyroid cartilage, 814
Corona glandls, 856
radiata, 64, 652
Corpora alblcantla, 621
Arantil, 805, 807
cavernosa clltorldis, 868
penis, 857
genlculata, 631
lutea, 875
ollvaria, 611
pyramldalia, 611
quadrlgemina, 631
restiformla, 611, 612
striata, 622, 625
veins of, 570
Corpus callosum, 619, 623
convolution of, 616
genu of, 623
peduncles of, 620, 624
raphe of, 624
rostrum of, 623
ventricles of, 623
cavernosum, 857
bulb of, 857
dentatum of cerebellum, 634,
635
of olivary body, 612
dentlculatum, 634, 635
genlculatum externum, 631
internum, 631
fimbrlatum, 626, 627, 623
Highmorianum, 862
luteum, 875
Corpus —
spongiosum, 857
bulb of, 858
striatum, 622, 625
See also Corpora.
Corpuscles, blood, 33
Malpighlan, of kidney, 796
of spleen, 795
Pacinian, 72
tactile, 71, 86
taste, 709
white, 34
Corti, cells of, 742
membrane of, 741
organ of, 741
rods of, 741
Cotunnlus, nerve of, 653
Cotyledons, 104
Coverings of hernia. See Her-
nia.
of testis. See Testis.
Cowper's glanda, 856, 901
Cranial nerves. See Nerves.
Cranium. See Skull.
bones of, 150
development of, 172
Cremaster, 860, 865, 881
Crest, frontal, 157
of Ilium, 247
nasal, 174
occipital, 150
Internal, 152
of pubes, 249
of tibia, 268
turbinated, of palate, 182
of superior maxillary, 177
Cricoid cartilage, 815
landmarks of, 930
Crista gain, 170
nil, 247
pubis, 249
Crown of tooth, 747
Crura cerebelll, 635
cerebri, 628
of clitoris, 868
of corpora cavernosa, 857
of diaphragm, 396
of fornix, 628
Crus penis, 856
Crustapetrosa of teeth, 750, 751
Crypts of Lleberkiihn, 775
Crystalline lens. See Lens,
crystalline.
Crystals, blood, 36
Cuboid bone, 269
Cuneiform bone of foot, 272
external, 273
internal, 272
middle, 273
of hand, 236
Cup, ocular, 114
Cupola of cochlea, 739
Curling on testes, 866
Curvatures of spine, 148
Cuspidate teeth, 748
Cutaneous nerves. See Nerves,
cutaneous.
Cuticle, 85
Cuticula dentis, 752
Cutis vera, 84
Cuvier, sinuses of, 119
960
INDEX.
Dartos, 860
Decidua, 104
reflexa, 104
serotina, 104
vera, 104
Deciduous teeth, 747
Decussation of optic nerve, 639
Deglutition, actions of, 745
Deiters, cells of, 742
Dens sapientijE, 749
Dentate body, 634
Dentine, 750
chemical composition of, 750
formation of, 750
secondary, 751
Depression, coronoid, 225
Derma, 84
Descemet, membrane of, 718
Development of atlas, axis, &c.
See Atlas, axis, &c., de-
veloj)nient of.
of organs, table of, 129
Diameters of pelvis, 253
Diaphragm, 394
development of, 122
lymphatics of, 600
openings of, 396
Diaphysis, 55
Diarthrosis, 281
rotatoria, 281
Differentiation of cells, 94
Digestion, organs of, 745
Diploe, 131
veins of, 569
Discus proligerus, 94
Disk, germinal, 98
Dissection of muscles, regions,
hernia, &c. See Muscles,
Regions, Hernia, &c.
Doyfere, hillocks of, 73
tufts of, 73
Duct or Ducts —
abeiTant, of testis, 863
of Bartholine, 759
biliary, 788, 790
common choledoch, 791
of Cowper's gland, 856
cystic, 790
ejaculatory, 805
■ of Gaertner, 125, 876
galactophorous, 877
hepatic, 786, 790
of kidney, 839
lachrymal, 177
lactiferous, 87 7
of liver, 786, 790
lymphatic, riLdit, 590
of IMulliT, 124
nasal, 177
landmarks of, 91 I
of jjancreas, 793
parotid, 758
prostatic, 853
seminal, 809
Sterio's, 758
thoracic, 589
vif.cllirie, 105
Wliarton's, 758
WoKlian, 123
Ductless glands. See Spleen,
Tliyroid, &c.
Ductus arteriosus, 813
how obliterated in foetus, 815
auditorius, 74l
cochlearis, 741
communis choledochus, 791
pancreaticus minor, 793
Eiviani, 759
venosus, 813
Duodenum, 771
vessels and nerves, 771
Dura mater of brain, 606
arteries of, 607
nerves of, 607
processes of, 608
sinuses of, 571
veins of, 607
of cord, 602
Eak, 729
arteries of,
auditory canal, 731
auricle of, 729
bones of, 735
cochlea, 739
development of, 114
external, 729
helix of, 729
internal, 738
labyrinth, 738
membranous, 743
middle, 732
muscles of, 344, 730
ossicula of, 735
pinna of, 729
semicircular canals, 739
tympanum, 732. See also
Tympanum.
vestibule, 738
Ejaculatory ducts, 865
Elbow, anastomoses around,
bend of, 511
joint, 310
vessels and nerves of, 312
landmarks of, 946
Embryo, human, 96
growth of, 104
Eminence of aquseductus Fal-
lopii, 734
canine, 175
frontal, 156
ilio-pectineal, 249
jugular, 151
nasal, 159
parietal, 154
Eminentia articularis, 160
collatcralis, 625, 627
Enamel of teeth, 751
formation of, 751
membrane, 751
jelly, 752
organ, 752
rods, 751
Enartlirosis, 282
Encephalon, 009
wciglit of, 010
l'jml-l)iill)s of Ki-auae, 71
J']n(h^car(liuin, 808
l^iulolym])!), 744
JOud-plates, motorial, nl' Kiiluic,
73
Ensiform appendix, 209
Epencephalon, 111
Epiblast, 96
Epidermis, 85
Epididymis, 861
Epiglottis, 816
Epiphyses, 54, 132
separation of, 55
Epithelium, 90
ciliated, 91
columnar, 91
conjunctival, 715
glandular, 91
pavement, 90
spheroidal, 91
tesselated, 90
Epoophoron, 125, 876
Erectile tissue, structure of, 85S
of clitoris, 868
of penis, 858
of vulva, 868
Ethmoid bone, 1 70
articulations of, 172
cribriform plate of, 170
development of, 171
lateral masses of, 171
perpendicular plate of, 17-
os planum of, 171
unciform process of, 171
Eustachian tube, 759
valve, 803
Eye, 713, 906
appendages of, 725
arteries of, 725
chambers of, 722
ciliary ligament, 719
muscle, 719
processes, 718
development of, 113
humors of, 722
aqueous, 722
crystalline lens, 723
vitreous, 723
landmarks of, 916
mcmbrana pupillaris, 719
membranes of, 714
choroid, 717
conjunctiva, 727
cornea, 715
hyaloid, 723
iris, 718
Jacob's, 720
retina, 720
sclerotic, 714
pupil of, 7 1 9
tunics of, 714
vessels of globe of, 725
Eyeball, 713
muscles of, 346
nerves of, 725
tunics of, 714
vessels of, 725
Eyebrows, 725
ICyelaslies, 727
Eyelids, 725, 916
cartihiges of, 726
development of, 1 14
Innilmarks of, 916
Meibomian glands of, 726
muscles of, 34 5^ 726
tarsal liganxnit of, 726
Eye-teeth, 748
INDEX.
9G1
Tace, arteries of, 478
bones of, 149, 174
landmarks of, 915
lymphatics of, 591
muscles of, 342
nerves of, 642
veins, 565
Fallopian tubes 873
development of, 125
fimbriated extremity of, 873
lymphatics of 598
nerves of, 876
structure of, 874
vessels of, 876
Falx cerebelli, 608
cerebri, 608
Fangs of teeth, 747
Fascia or Fasciaj, 340
anal, 906
aponeurotic, 341
of arm, 407
cervical, deep, 357
superficial, 356
costo-coracoid, 401
of cranial region, 342
cremasteric, 860, 882
cribriform, 433, 888
deep, 341
of arm, 407
of forearm, 410
of leg, 446
of thorax, 399
dentata, 627
dorsal, of foot, 457
fibro-areolar, 340
of foot, 453
of forearm, 410
of hand, 420
iliac, 430
infundibuliform, 883
of inguinal region, 878
intercolumnar, 387, 860, 880
intercostal, 392
intermuscular, of arm, 407
of foot, 454
of thigh, 433
ischio-rectal, 896, 906
lata, 433, 889
falciform process of, 889
iliac portion of, 434
pubic portion of, 434
of leg, 445
deep, 450
lumbar, 389
lumborum, 389
of mamma, 877
of neck, 356
obturator, 906
palmar, 421
pelvic, 905
perineal, deep, 899, 900
superficial, 897
plantar, 454
landmarks of, 944
propria of femoral hernia, 894
of spermatic cord, 860
recto- vesical, 906
spermatic, 887, 880
subperitoneal, 889
superficial, 340
of cranial region, 342
61
Fascia —
of inguinal region, 878
deep layer, 879
of ischio-rectal region, 896
perineal, 897, 900
of thigh, 432
of thoracic region, 399
of upper extremity, 399
temporal, 353
of thigh, deep, 433
supei-ficial, 432
of thorax, 399
transversalis, 882
Fasciculi graciles, 611
teretes, 612
Fasciculus, olivary, 612
unciformis, 620
Fat, 41
Fauces, isthmus of, 756
pillars of, 756
Features as landmarks, 919
Fecundation of ovum, 95
Female organs of generation,
867
bulbi vestibuli, 869
caruncula; myrtiformes, 868
clitoris, 868
developnient of, 125, 127
fossa navicularis, 868
fourchette, 868
frasnulum pudendi, 868
glands of Bartholine, 868
hymen, 868
labia majora, 867
minora, 868
mons veneris, 867
nympha;, 868
pr^putium clitoridis, 868
uterus, 871
vagina, 870
vestibule, 868
vulva, 867
Femoral hernia. See Hernia,
femoral.
Femur, 254
articulations of, 259
attachment of muscles to, 260
development of, 259
fracture of, 460
structure of, 259
Fenestra ovalis, 733, 740
rotunda, 733, 740
Fenestrated membrane of Hen-
le, 76
Ferrein, pyramids of, 843
Fibr£e arciformes, 611, 613
transversse, 632
Fibre cells, muscular, 57
Fibres, of Corti, 741
of muscle, 57
intercolumnar, 880
of nerA'C, 63
Tomes's, 753
Fibrillaj, 62
fibrous, 39
Fibro-cartilage, 45
acromio-clavicular, 306
circumferential, 46
connecting, 45
interarticular. See Interarti-
cular fibro-cartilage.
Fibro-cartilage —
intercoccygean, 303
interosseous, 279
intervertebral, 286
of knee, 328
of lower jaw, 294
pubic, 304
radio-ulnar, 314
sacro-coccygeal, 303
semilunar, 328
sterno-clavicular, 305
stratiform, 46
triangular, 314
Fibrous tissue, white, 39
yellow, 39
Fibula, 265
articulations of, 266
attachment of muscles to, 267
development of, 266
fracture of, with dislocation
of the tibia, 461
landmarks of, 939, 941
Filaments, spermatic, 865
Filum terminale of cord, 604
Fimbrise of Fallopian tube, 873
Fingers, 243
landmarks of, 950
Fissura palpebrarum, 725
Fissure, auricular, 164
calcarine, 619
calloso- marginal, 619
of cerebellum, 634
of cerebrum, 619
of cranial bones, congenital,
173
of ductus venosus, 784
of eyelids, 725
for gall-bladder, 785
Glaserian, 160, 733
horizontal, of cerebellum,
634
interparietal, 617
of liver, 784
longitudinal, of cerebrum, 619
of liver, 784
of lung, 829
maxillary, 177
of medulla oblongata, 610
palpebral, 725
parieto-occipital, 617
portal, 785
pterygo-maxillary, 200
of Rolando, 616
of skull, 173
spheno-maxillary, 200
sphenoidal, 168, 200
of spinal cord, lateral, 605
median, 605
of Sylvius, 616, 620
of the tragus, 730
transverse, of cerebrum, 627
of liver, 785
umbilical, of liver, 784
for vena cava, 785
Flexure, caudal, 100
cephalic, 100
hepatic, 779
sigmoid, 779
splenic, 779
Flocculus, 633, 634
Fluid, cerebro-spinal, 609
062
INDEX,
Foetus, circulation in, 812
development of, 104
ductus arteriosus of, 812
Eustachian valve in, 810
foramen ovale in, 810
liver of, distribution of ves-
sels in, 812
ovaries in, 123
peculiarities of vascular sys-
tem in, 810
relics in heart of, 812
Folds, aryteno - epiglottidean,
816
genital, 127
interdigital, 949
palpebral, 727
recto-uterine, 871
recto-veslcal, 851
vesico-uterine, 871
Follicles, dental, 754
gastric, 770
hair, 87
intestinal, 7 75, 782
of Lieberkiihn, 775
sebaceous, 88
of tongue, 709
Fontanelles, 153, 156, 172
Fontana, canal of, 718
Foot, arteries- of, 557, 561
bones of, 207
development of, 276
fascia of, 453
landmarks of, 943
ligaments of, 332
muscles of, 453, 455
nerves of, 693
veins of, 581
Foramen. See also Foramina,
caecum of frontal bone, 157,
194
of medulla oblongata, 610
of tongue, 708
carotid, 1G3
condyloid, 151, 153
cotyloid, 250
dental, inferior, 188
ethmoidal, 174
incisive, 197
infraorbital, 175
intervertebral, 149
for Jacobson's nerve, 163
jugular, 151, 195
laccrum anterius, 195
medium, 162, 195
posterius, 151, 103, 195
magnum, 151
mastoid, 161
medullary of tibia, 2C4
mental, 180
of Monro, 625, 280
obturator, 250
optic, 160, 108, 194
ovale of heart, 810
offiphcnoid, 107, 195
palatine, anterior, 178, 197
posterior, 184, 197
parlcital, ] 55
pterygoid, 108
pterygo-])alatinc, 107
rotunchim, 107, 1 95
eucro-sciatic, 248, 301
Foramen —
of Sommering, 720
spheno-palatine, 184, 205
spinosum, 167, 195
sternal, 207
stylo-mastoid, 164
sujiraorbital, 157
thyroid, 250
vertebral, 133
Vesalii, 167
of Winslow, 765
Foramina of diaphragm, 396
external orbital, 168
efface, landmarks of, 916
incisive, 197
malar, 180
olfactory, 170
sacral, 143, 144
Thebesii, 587, 803
See also Foramen.
Forearm, arteries of, 515
bones of, 228, 233
fascia of, 410
landmarks of, 947
lymphatics of, 594
muscles of, 410
nerves of, 6 73
veins of, 5 74
Forebrain, 110
Foreskin, 857
Fornix, 627, 629
body of, 628
bulbs of, 621, 628
crura of, 628
Fossa of antihelix, 729
canine, 175
cerebral, 192
condyloid, 151
coronoid, 227
cystidis felleje, 785
digastric, 161, 187, 198
digital, 256
glenoid, 160
of helix, 729
iliac, 247
infraclavicular, landmarks of,
923
incisive, 175, 186
infraspinous, 219
innominata, 729
isehio-reetal, 890
jugular, 163, 104, 198
lachrymal, 158
myrtiform, 175
navicular of in-ethra, 854
of vulva, 808
occipital, 151
olecitinon, 226
olfactory, of foetus, 1 1 5
ovalis, 804
palatine, anterior, 178, 195
j/ituitary, 160
j)terygoid of sphenoid, 108
of lower jaw, 188
scaplioid, 169
Sfajihoidea, 729
of skull, antei-ior, 192
middle, 194
posterior, 1 95
splicno-inaxillary, 200
sublingual, 187
Fossa —
submaxillary, 187
subscapular, 218
supraclavicular, landmarks
of, 921
supraspinous, 218
temporal, 157, 159, 199
trochanteric, 256
zygomatic, 200
Fossa3, cranial, 192
nasal, 203, 712
vessels and nerves of, 743
Fourchette, 868
Fovea centralis retinae, 720
hemispherica, 738
seml-elliptica, 739
Fracture of acromion process,426
clavicle, 426
acromial end of, 420
centre of, 420
sternal end of, 420
CoUes's, 428
coracoid process, 426
coronoid process of ulna, 427
femur above condyles, 460
below trochanters, 460
neck of, 460
fibula, with dislocation of ti-
bia, 461
humerus, 426
anatomical neck, 427
shaft of, 427
surgical neck, 420
olecranon process, 427
patella, 401
Pott's, 401
radius, 428
lower end of, 428
neck of, 428
shaft of, 428
and ulna, 428
tibia, 461
ulna, 428
Frajna of ileo-ececal valve, 779
Frainulum cerebri, 631
pudendi, 868
valve of Vieussens, 631
Frajnum clitoridis, 868
labii inferioris, 745
superioris, 745
lingua?, 364, 708
pra'putii, 850
Frontal bone, 156
articulations of, 159
attachment of muscles to.
159
development of, 159
structure of, 159
Frontal sinuses, 158
landmarks of, 914
Fundus of bladder, 850
of uterus, 8 71
FiuTOw, auriculo- ventricular,
802
digital, 919
genital, 1 27
interventricular, 802
Furrowed band, 633
Gakutnku, duct of, 125, 870
Galen, A'cins oi", 570, 58 7
INDEX.
963
Gall-bladder, 789
development of, 122
duct of, 790
fissure for, 785
landmarks of, 932
structure of, 790
valve of, 790
Ganglion or Ganglia —
Arnold's, 656
of Andersch, 659
of Boclidalek, 653
cardiac, 701
carotid, 698
Casserian, 648
cephalic, 650, 696
of cerebellum, 635
cervical, inferior, 699
middle, 699
superior, 698
ciliary, 650
on circumflex nerve, 673
diaphragmatic, 702
on facial nerve, 643
of fifth nerve, 650
general anatomy of, 68
glosso-pharyngcal, 659
impar, 696, 704
inferius, 661
intercarotid, 699
on interosseous nerve, poste-
rior, 680
jugular, 659, 660
lenticular, 650
lingual, 699
lumbar, 704
lymphatic. See Lymphatic
glands.
Meckel's, 652
mesenteric, 703
ophthalmic, 650
otic, 656
petrous, 659
pharyngeal, 699
pneuniogastric, 660
of portio dura, 643
renal, 703
of Eibcs, 696
roots of, 650
sacral, 704
semilunar of abdomen, 702
of fifth nerve, 648
of sympathetic, 702
solar, 702
spheno-palatine, 652
of spinal nerves, 666
spirale, 741
submaxillary, 657
suprarenal, 702
of sympathetic nerve, 696
temporal, 699
thoracic, 701
thyroid, 699
of vagus, root of, 661
trunk of, 661
of Wrisberg, 701
Ganglion corpuscles, 68
Gaps, congenital, ofcranium,! 73
Geniculate bodies, 629
Generative organs, female. See
Female organs of genera-
tion.
Generative organs —
male. See Penis, Scrotum,
&c.
Genito-urinary organs, develop-
ment of, 122
Genu of corpus callosum, 623
Germinal area, 98
matter, 38
spot of ovum, 98
vesicle of ovum, 98
Gimbernat's ligament, 386, 881,
890
Ginglymus, 282
Giraldbs, organ of, 126
Gladiolus, 207
Gland or Glands —
absorbent, 82, 588
accessory of parotid, 758
aggregate, 776
agminate, 776
arytenoid, 822
of Bartholine, 868
of biliary ducts, 788
Brunner's, 775
buccal, 746
ceruminous, 732
coccygeal, 534
conglobate, 588
Cowper's, 856, 901
development of, 115
duodenal, 775
ductless. See Spleen, Thy-
mus, &c.
epiglottic, 822
gastric, 771
genital, 126
of Havers, 280
inguinal, 887
kidney, 838
labial, 745
lachrymal, 728
of larynx, 822
lingual, 709
of Littr6, 854
liver, 783
lumbar, 534
Luschka's, 534
lymphatic, 588. See Lym-
phatic glands.
mammarj^, 876
Meibomian, 726
mesenteric, 599
molar, 754
mucilaginous of Havers, 280
mucous, of stomach, 770
odorifera3, 856
CESophageal; 761
of Pacchioni, 605, 607
palatal, 756
pancreas, 791
parotid, 757
peptic, 770
Peyer's, 776
pharyngeal, 760
pineal, 630
pituitary, 621
prostate, 855, 902
salivary, 757
sebaceous, 88
secreting, 93
solitary, 7 75, 782
Gland or Glands —
sublingual, 759
submaxillary, 758
sudoriferous, 89
suprarenal, 846
sweat, 89
thymus, 836
thyroid, 834
of tongue, 709
tracheal, 824
trachoma, 727
of Tyson, 856
uterine, 872
of vagina, 871
of vulva, 868
Glandula; odor if eras, 856
Pacchioni, 605, 607
solitarias, 775, 782
Tysonii, 856
Glans clitoridis, 868
penis, 856
Glaser, fissure of, 160
Gliding movement, 284
Glioma, 64
Glisson's capsule, 786
Globe of eye. See Eye.
Globus major of epididymis, 861
minor of epididymis, 861
Globules, blood, 33
polar, 95
Glomerulus arterio-coccygeus,
534
vascular of kidney, 841
Glottis, 818
rima of, 818
Gomphosis, 281
Graafian vesicles, 874
membrana granulosa of, 875
ovicapsule of, 875
structure of, 875
Granular layer of dentine, 750
Granules, seminal, 865
Gray matter of cerebellum, 634
of cerebrum, 615
of fourth ventricle, 635
of medulla oblongata, 612
of spinal cord, 66
of third ventricle, 630
Groin, 878
cribriform fascia of, 433, 888
cutaneous vessels and nerves
of, 878
landmarks of, 937
lymphatic glands of, 594, 595,
937
region of, 878
superficial fascia of, 878
surgical anatomy of, 878
Groove, auriculo- ventricular,
802
basilar, 153
bicipital, 225
cavernous, 166
dental, 751
secondary, 754
infraorbital, 176, 202
lachrymal, 179, 202
musculo-spiral, 225
mylo-hyoid, 188
na"sal, 109, 174
occipital, 161
9G4
INDEX.
Groove —
olfactory, 115, 194
optic, 1G6
primith-e, 98
sacral, 144
subclavian, 217
Grooves in radius, 234
ventricular, 802
Growth of bone, 54 •
of body, 94
Gubernaculuni testis, 865
Gums, 746
Gyri operti, 618, 620
Gyrus fornicatus. 616, 623
Hair-cells of ear, 741
Hairs, 87
follicles of, 87
root of, 87
shaft of, 88
sheath of, 88
structure of, 87
Ham, region of, 552
Hamstring tendons, surgical
anatomy of, 445
Hand, arteries of, 517, 519
bones of, 235
development of, 244
fascia of, 420
landmarks of, 948
ligaments of, 319
muscles of, 420
nerves of, from median, 675,
677
from radial, 679
from ulnar, 678
veins of, 574
Harmonia, 281
Havers, canals of, 48
glands of, 280
Head, lymphatics of, 590
muscles of, 242
veins of, 565
Heart, 801
annular fibres of auricles, 804
apex of, 809
landmarks of, 924
arteries of, 469, 479, 810
auricles of, 801, 802
circular fibres of, 809
component parts of, 801
development of, 116
endocardium, 808
fibres of auricles, 808
of ventricles, 808
fibrous rings of, 808
foetal relics in, 812
infundibulum of, 804
landmarks of, 923
left auricle, 806
ventricle, 807
looped filjres of auricles, 808
lymphatics of, 600, 810
muscular structunj of, 808
nerves of, G62, 699, 810
openings into, 803, 804
outline of, on chest-wall, 923
peculiarities of, in fcjulus, 811
])osition of, 801
right auricle, 802
ventricle, 804
Heart —
sejDtum ventriculorum, 804
sinus of, 802
size and weight of, 801
spiral fibres of, 809
structure of, 808
subdivision into cavities, 801
valves of, 803, 807
landmarks of, 925
veins of, 810
ventricles of, 801
vortex of, 809
Helicotrema of cochlea, 739
Helix, 729
fossa of, 729
muscles of, 729
process of, 730
Henle, fenestrated membrane
of, 76
looped tubes of, 840, 842
Hernia, congenital, 885
direct inguinal, 885
course of, 885
coverings of, 886
diagnosis of, 886
incomplete, 886
femoral, complete, 894
cutaneous vessels and nerves
of, 886
coverings of, 894
descent of, 893
dissection of, 886
incomplete, 894
seat of stricture in, 894
surgical anatomy of, 886
varieties of, 894
infantile, 885
inguinal, 878, 884
dissection of, 878
direct, 885
external, 884
incomplete, 885
internal, 884
surgical anatomy of, 878
vessels and nerves involved,
oblique inguinal, 882, 884
complete, 885
course of, 884
coverings of, 884
scrotal, 885
Hesselbach's triangle, 885
Hey's ligament, 889
Hiatus Fallopii, 162
Highmore, antrum of, 177
Hilton's muscle, 819
Hilum of kidney, 838
pulmonis, 829
of spleen, 793
Hinge-joint, 282
Hip-joint, 322
muscles of, 433, 437
IIij)pocampus major, 627
minor, 625
Holoblastic ova, 95
Horny band, 625
lluguier, canal of, 161, 645, 733
nuiuerus, 223
arficulations of, 228
attacliiiient of muscles to, 228
devel()])nient of, 227
Humerus —
fractures of, 426
landmarks of, 944
tuberosities of, 225
Humors of eye, 722
Hunter, canal of, 547
Hyaloid membrane of eye, 723
Hydatid of Morgagni, 126
Hymen, 868
Hyoid bone, 206
attachment of muscles to, 206
development of, 206
landmarks of, 920
Hypoblast, 96
Ileum, 772
Ilium, 246, 247
landmarks of, 930
Impressio colica, 785
renalis, 785
Impression, deltoid, 225
rhomboid, 216
Incisive bone, 178, 179
Incisor teeth, 747
Incisura cerebelli, 632
intertragica, 729
Santorini, 732 _
Incus, 735
ligament of, 736
suspensory, 736
Inferior maxillary bone, 186
articulations of, 190
attachment of muscles to, 190
changes produced by age in,
190
dcA'clopment of, 190
landmarks of, 916
ligaments of, 293
Infundibula of kidney, 839, 846
Infundibulum of brain, 111, 621
of cochlea, 739
of ethmoid, 172
of heart, 804
Ingrassias, processes of, 168
Inguinal hernia. See Plernia.
Inlet of pelvis, 253
Innominate bone, 245
articulations of, 251
attachment of muscles to,
251
development of, 251
Interarticular libro-cartilage, 45
of jaw, 294
of knee, 328
of pubes, 304
of radio-ulnar joint, 314
of sacro-coccygeal joint,
303
of scapulo-clavicular joint,
306
of sterno-clavicular joint,
305
Intcrcalat(!d convoluted tube,
842
Intercellular passage of lung,
833
substance of cartilage, 44
Intercostal spaces, 211
Intcrtubular tissue, 750
Int(>rniaxillary b<inc, 178, 179
Intervertebz-al substance, 286
INDEX.
965
Intestine, development of, 121
large, 7 77
cellular coat of, 782
development of, 121
ileo-ca3cal valve, 778
landmarks of, 933
mucous membrane of, 782
muscular coat of, 781
serous coat of, 781
small, 771
■^ cellular coat of, 773
divisions of, 771
glands of, 775
landmarks of, 934
lymphatics of, 599
mucous coat of, 773
muscular coat of, 773
serous coat, 772
simple follicles of, 775
stnicture of, 772
valvulte conniventes, 773
villi of, 773
Intumescentia gangliformis, 643
Investing mass, 108
Iris, 717
Ischium, 246, 248
Island of Reil, 616, 618, 620
Isthmus of fauces, 756
of thyroid gland, 834
Iter ad infundibulum, 630
a tertio ad quartum ventri-
culum, 630, 631
chordae anterius, 733
posterius, 645, 733
Ivory of tooth, 750
Jacob's membrane, 720
Jacobson's nerve, 659, 737
canal for, 163
Jaw, lower. See Inferior max-
illary bone,
upper. See Superior maxil-
lary bone.
Jejunum, 772
Jelly, enamel, 752
of Wharton, 41, 105
Joint. See Articulations.
Kerkring, valves of, 773
Kidney, 838
apex of, 840
arteries of, 843
calices of, 83 9, 846
capsule of, 840
cortical column of, 840
substance of, 840
development of, 124
ducts of, 839
hilum of, 838
infundibula of, 846, 849
landmarks of, 933
lobes of, 840
lymphatics of, 598, 845
Malpighian bodies of, 840, 841
capsule, 841
tuft, 841
mammillas of, 840
medullary substance of, 841
minute structure of, 841
nerves of. 845
papilla of, 840
Kidney —
pelvis of, 839, 846
primordial, 123
pyramids of Ferrein, 843
'of Malpighi, 839, 840
relations of, 838
sinus of, 838
stroma of, 845
tubull contort! urlniferi, 842
veins of, 845
weight and dimensions of,
838
Knee-joint, 325
landmarks of, 939
Knuckles, landmarks of, 950
Krause, end-bulbs' of, 7 1
Kuhne on motor nerves, 73
Kiirschner on valves of heart,
806
Labia cerebri, 622
majora, 867
minoi-a, 868
lymphatics of, 598
Labium tympanicum, 741
vestibulare, 741
Labyrinth, 738
arteries of, 744
membranous, 743
nerves of, 744
veins of, 744
Lachrymal apparatus, 727
bones, 179
articulations of, 180
attachment of muscles to,
180
development of, 180
sac. See Sac.
Lacteals, 599, 774
Lacuna magna, 854
Lacunse of bone, 49
Lacus lacrymalis, 725, 727
Lamella, articular, 279
of bone, 49
horizontal, of ethmoid, 170
interstitial, 49
perpendicular, of ethmoid,
171
Lamina cinerea, 619, 620
cribrosa of sclerotic, 714
denticulate of cochlea, 741
fusca of sclerotic, 714
membranacea, 741
reticular, 742
spiralis of cochlea, 739, 741
Laminae of cerebellum, 634
of cornea, elastic, 715
dorsales, 98
ofvertebrte, 133
Laminated tubercle of cerebel-
lum, 633
Lancisi, nerve of, 624
Landmarks, medical and surgi-
cal, 913
abdomen, 928
bony prominences of, 930
lines of, 928
manipulation of, 931
rings of, 931
viscera of, 931
ankle, 941
Landmarks —
anterior tibial artery, 942
antrum, 918
anus, 935
aorta, division of, 930
arm, 944
cutaneous veins of, 946
axilla, 945
axillary artery, 945
back, 926
furrows of, 926
bladder, 934
brachial artery, 945
brain, levels of, 915
bursa, carpal, 948
digital, 950
of elbow, 947
of foot, 943
of patella, 940
buttocks, 938
carpus, 947
catheter, introduction of, 936
chest, 922
in the female, 922
clavicle, 944
region above, 921
below, 923
colotomy, 933
condyles of humerus, 946
coraco-acromial ligament, 945
cricoid cartilage, 920
crural arch, 931, 936
cutaneous veins of arm, 946
diaphragm, 932
digital arteries, 949
furrows, 949
joints, 950
dorsal artery of foot, 943
elbow, 946
cutaneous veins of, 946
epigastric artery, 931
eyelids, 916
eyes, 916
face, 915
facial artery, 916
features, 919
femoral artery, 938
compression of, 938
ring, 936
fibula, 941
fingers, 949
foo't, 943
arteries of, 943
bones of, 943
bursa of, 943
joints of, 943
foramina for fifth nerve, 916
forearm, 947
gall-bladder, 932
gluteal artery, 937
groin, 937
hand, 949
heart, 923
apex of, 924
outlines of, 923
valves of, 925
Hunter's canal, 938
hyoid bone, 920
ilium, 930, 987
prominences of, 930
inguinal canal, 931
966
INDEX.
Landmarks —
inguinal glands, 937
interdigital folds, 949
internal mammary artery, 923
interosseous arteries of arm,
947
of hand, 950
intestines, large, 933
small, 934
kidney, 933
knee, 939
bony prominences of, 939
synovial membrane of, 940
knuckles, 950
lachrymal sac, 917
leg, 941
ligamentum patellae, 940
linea alba, 929
linese semilunares, 928
transversas, 929
liver, 932
lower jaw, 916
lung, 925
apex of, 921
outlines of, 925
malleoli, 941
mastoid process, 915
mediastinum, anterior, 925
metacarpal joints, 949
middle meningeal artery, 915
mouth, 918
nares, 919
nasal cavities, 917
duct, 917
neck, veins of, 920
N^laton's line, 937
nose, 917
occipital protuberance, 915
olecranon, 946
palm of hand, 949
palmar arches, 949
palpation by rectum, 950
pancreas, 933
parotid duct, 916
patella, 939
patellar bursa, 940
perineum, 934
bony framework of, 934
raphe of, 934
peritoneum, 930
peroneal nerve, 941
pit of the stomacli, 929
plantar arteries, 944
fascia, 944
pleura, reflections of, 925
pomum Adanii, 920
popliteal artery, 940, 942
bursa, 940
tendons, 940
posterior tibial artery, 942
Poupart' 8 ligament, 930, 931,
936
prostate gland, 935
pubcs, bony j)roniincnccs of,
930
pudic artery, 939
pulley for superior ol)li(|uc.
916
pulse at wrist, 948
puiicta lacryinalia, 917
Landmai'ks — ■
pylorus, 932
radial artery, 948
radius, 947
raphe of perineum, 934
rectum, 935
palpation by, 950
ribs, rules for counting, 923
rings, abdominal, 931
femoral, 936
saphenic veins, 945
saphenous opening, 936
sartorius, 938
scalp, 914
arteries of, 914
density of, 914
scapula, 928
sesamoid bones, 950
skin, 941
shoulder, 944
sinuses, cerebral, 915
frontal, 914
skullcap, 913
thickness of, 915
spermatic cord, 931
spinal meshes, origins of, 927
spine, movements of, 927
of ilium, 930, 937
of pubes, 930
spines of vertebrae, 926
spleen, 93 2
stern o-clavicular j oint, 921
sterno-mastoid muscle, 921
sternum, 922
stomach, 932
subclavian artery, 922
subcutaneous veins of hand,
950
of neck, 920
supraclavicular fossa, 921
supracondyloid processes, 946
tabatifere anatomique, 948
temporal artery, 916
tendo Achillis, 941
tendons of ankle, 941, 942
of wrist, 948
thigh, 936
bend of, 936
throat, 918
thumb, 949
thyroid cartilage, 920
tibia, 941
tonsils, 919
trachea, 921
division of, 926
triangular ligament, 935
trigonura vesica?, 934
trocliantcrs, 937
tuberosities of arm, 944
ulna, 94 7
uhiar artery, 948
uiidjilicus, 929
urethra, 935
In cliild, 936
vagina, examinations of, 951
vertel)ra3, spines of, 926
tabular ])l;in of, 927
Aisccra, abdominal, 931
wrist, 94 7
Laryngo-trachcotomy, 834
Laryngotomy, 824
Larynx, 814
cartilages of, 814
cavity of, 818
glands of, 822
glottis, 818
interior of, 817
ligaments of, 816
mucous membrane of, 821
muscles of, 819
actions of, 821
rima glottidis, 818
superior aperture of, 817
ventricle of, 818
vessels and nerves of, 822
vocal cords of, false, 818
inferior, 819
superior, 818
true, 819
Lee, researches on sympathetic
nerve, 705
Leg, arteries of, 552
bones of, 260
fascia of, 446
deep, 450
landmarks of, 940
ligaments of, 330
lymphatics of, 594
muscles of, 446
nerves of, 684
veins of, 581
Lens, crystalline, 723
capsule of, 723
changes produced in by age,
724
development of, 113
structure of, 724
suspensory ligament of, 724
Lieberkiihn, crypts of, 775
Ligament or Ligaments, acces-
sory, 308
acromio-clavicular, superior,
306
inferior, 306
alar of knee, 329
of ankle, anterior, 332
lateral, 332
annular of ankle, 453
anterior, 453
external, 454
internal, 454
of i-adius and ulna, 315
of stapes, 736
of wrist, anterior, 420
postei'ior, 420
anterior of ankle, 453
of carpus, 317
of elbow, 311
of knee, 326
of wrist, 316
arcuate, 395
ary teno-epiglottic, 816
astragalo-scaphoid, 334
atlo-axoid, anterior, 289
])osterior, 289
of bladder, false, 850
true, 850
broad, of liver, 783
of uterus, 765, 871
Burns's, 889
INDEX.
9G7
Ligament or Ligaments —
calcaneo-astragaloid, exter-
nal, 324
interosseous, 334
posterior, 334
calcaneo-cuboid, internal, 335
long, 335
short, 335
superior, 335
calcaneo-scaplioid, inferior,
336
superior, 336
of Camper, 900
capsular. See individual
Joints,
carpo-metacarpal, 319
of carpus, 317
central, of spinal cord, 604
check, 292
ciliary of eye, 718, 719
common vertebral, anterior,
285_
posterior, 285
conoid, 306
coraco-acromial, 307
landmarks of, 945
coraco-clavicular, 306
coraco- humeral, 308
coracoid, 308
coronary of knee, 329
of liver, 784
costo-clavicular, 305
costo-sternal, anterior, 297
posterior, 297
costo- transverse, 296
costo-vertebral, 295
costo-xiphoid, 299
cotyloid, 324
crico-arytenoid, 817
crico- thyroid, 817
crucial of knee, 327
cruciform, 289
deltoid, 332
dorsal. See individual Joints.
of elbow, 310
anterior, 311
external lateral, 311
internal lateral, 311
posterior, 311
falciform of liver, 783
femoral, 889
gastro- phrenic, 767
Gimbernat's, 386, 881, 890
glenoid, 308, 321
glosso-epiglottidean, 816
Key's, 889, 937
of hip, 322
hyo- epiglottic, 816, 817
ilio-femoral, 323
ilio-lumbar, 300
of incus, 736
interarticular of ribs, 296
interchondral, 299
interclavicular, 305
intercostal, 297
interosseous. See individual
Joints,
interspinous, 287
intertransverse, 288
intervertebral, 285
of jaw, 292
Ligament or Ligaments —
of knee, 325
of larynx, 816
lateral. See individual Joints.
of liver, 783
of uterus, 871
of liver, 783
longitudinal of liver, 783
lumbo-iliac, 300
lumbo-sacral, 300
of malleus, 736
metacarpal, 319, 321
metacarpo- phalangeal, 321
metatarsal, 338
metatarso- phalangeal, 338
oblique, 313
obturator, 304
occipito-atloid, anterior, 291
lateral, 292
posterior, 291
occipito-axoid, 292
odontoid, 292
orbicular, 313
of ossicula, 736.
of ovary, 876
palmar, 317
palpebral, 726
of patella, 326
landmarks of, 940
of pelvis, 300
peritoneal, 765
of phalanges of hand, 322
of foot, 338
of pinna, 730
plantar, 337, 338
posterior of carpus, 317
of elbow, 311
of knee, 327
of wrist, 316
Poupart's, 386, 880, 890
pterygo-maxillary, 352
pubic, anterior, 303
posterior, 303
superior, 303
pubo-prostatic, 850, 855, 907
radio-carpal, 315
radio-ulnar, anterior, 314
inferior, 314
middle, 313
posterior, 314
recto-uterine, 871
rhomboid, 305
round, of hip, 323
of liver, 783, 784
of radius and ulna, 313
of uterus, 876
sacro-coccygeal, anterior, 202
posterior, 302
sacro-iliac, anterior, 301
oblique, 301
posterior, 301
sacro-sciatic, anterior or pos-
terior, 301
lesser or anterior, 301
sacro-vertebral, 302
of scapula, 307
scapulo-clavicular, 306
of shoulder, 308
of spleen, 794
of stapes, 736
stellate, 295
Ligament or Ligaments —
sternal, 299
sterno - clavicular, anterior,
304
posterior, 304
of sternum, 299
structure of, 279
stylo-hyold, 294
stylo- maxillary, 294, 357
subflavous, 287
subpubic, 303
supraspinous, 288
suspensory, of incus, 736
of lens, 724
of liver, 783
of malleus, 736
of mamma, 399
of penis, 856
of spleen, 795
sutural, 279
tarsal, 334
of eyelids, 726
tarso-metatarsal, 337
of thumb, 321
thyro-arytenoid, inferior, 819
superior, 818
thyro-epiglottic, 816, 817
thyro-hyold, 817
tibio-fibular, 330
tibio- tarsal, 332
transverse of atlas, 289
of hip, 325
of knee, 329
of scapula, 308
of tibio-libular, 331
trapezoid, 306
triangular, 386, 881, 900
landmarks of, 935
of urethra, 881
of tympanic bones, 736
of uterus, 871
of vertebras, 285
veslco-uterine, 871
of Winslow, 327
of wrist, 315
anterior, 316
lateral, external, 316
internal, 316
posterior, 316
Y, 323
of ZInn, 347
See also LIgamenta and
Ligamentum.
LIgamenta alarla, 329
subflava, 28 7
suspcnsoria of mamma, 399
See also Ligament.
Ligamentum arcuatum exter-
num, 396
internum, 395
dentatum, 604
dentlculatum, 604
latum pulmonis, 826
mucosum, 329
nuchEB, 374
patellae, 326
pectlnatum iridis, 718
landmarks of, 940
posticum AVinslowii, 327
spirale, 741
suspensorlum, 292
968
INDEX.
Ligamentum —
teres. See Ligament, round.
See also Ligament.
Ligation of arteries. See Ope-
ration.
Limbs, bones of, 215
development of, 116
Limbus laminae spiralis, 741
luteus, 720
Line, curved, of occipital bone,
151
incremental, 750
intertrochanteric, 206
mylo-hyoidean, 187
K'elaton's, 937
oblique, of clavicle, 216
of fibula, 256
of lower jaw, 187
of radius, 234
of tibia, 263
Linea alba, 391
landmarks of, 929
aspera, 257
ileo-pcctinea, 247
quadrati, 256
splendens, 603
Linese semilunares, 392
landmarks of, 928
transversa; of abdomen, 390,
392
landmarks of, 929
of auditory nerve, 639
of fourth ventricle, 63 G
Lingual bone, 206
Linguetta laminosa, 631
Lips, 745
arteries of, 479, 480
Liquor amnii, 101
chyli, 38
Cotunnii, 743
Morgagnii, 723
sanguinis, 33, 35
Scarpae, 744
seminis, 865
Lithotomy, parts avoided in, 904
parts concerned in, 903
divided in, 904
Littr6, glands of, 854
Liver, 783
arteries of, 527, 786, 789
changes of position in, 783
circulation in, 788
coats of, 786
development of, 119, 122
distriljution of vessels to, in
fa;tus, 812
ducts ol", 788
fissures of, 784
landmarks of, 932
ligaments of, 783
loljcs of, 785
lobiilcs of, 786
lymphatics of, 598, 786
nerves of, 786
Bituation, bIzc, and weiglit,
783
structure of, 786
surfaces and borders of, 783
vessels of, 786
Lobes of cercbcUum, 634
digastric, G34
Lobes —
inferior, posterior, 634
median, 634
pneumogastric, 634
slender, 634
square, 634
subpeduncular, 634
of cerebrum, 618. See Cere-
brum.
of kidney, 840
of liver, 785
of lung, 830
optic, 631
of prostate, 855
of testis, 862
of thymus, 836
of thyroid, 834
See Lobules, &c.
Lobule of ear, 729
Lobules, cuneate, 619
of kidney, 840
of lung, 833
Lobulettes of lung, 833
Lobuli testis, 862
Lobulus caudatus, 786
centralis of cerebellum, 632
priEcuneus, 619
quadra tus, 619, 786
Spigelii, 786
Lobus. See Lobules and Lobes.
Locus caeruleus, G35
niger, 622
perforatus anterior, 620
posterior, 621
Looped tubes of Henle, 840
Lower extremity, arteries of, 545
bones of, 245
fascia of, 429
ligaments of, 322
lymphatics of, 594
muscles of, 429
nerves of, 690
veins of, 580
Lower jaw. See Inferior maxil-
lary bone.
Lower, tubercle of, 803
Lungs, 827
air-cells of, 833
air-sacs of, 833
alveoli of, 833
apex of, 828
landmarks of, 921
capillaries of, 833
development of, 122
fissures of, 829
infa-tus, 122
landmarks of, 925
lobes and fissures of, 830
lobules of, 833
lobulettes of, 833
lymphatics of, 600, 834
nerves of, 834
outline ol', on cliest-wall, 925
});ircin'liyma of, 831
pulmonary artery, 563, 804,
833
veins, 554, 587, 833
root of, 830
Htrncturn of, 831
subdivision of bronchi in, 831
vessels of, 833
Lungs —
weight, color, etc., 831
Lunulas of nails, 8 7
Luschka's gland, 534
Lymph, 3 7
Lymph-path, 82
sinus, 82
Lymphatic duct, right, 590
Lymphatic glands, 82, 588
auricular, posterior, 590 ,
axillary, 594
brachial, 593
broncliial, 601
buccal, 590
cervical, 592
of elbow, 593
gluteal, 595
of groin, 594, 595, 937
of head, superficial, 590
iliac, external, 596
internal, 696
inguinal, deep, 595
superficial, 594
intercostal, 600
internal mammary, 600
ischiatic, 595
of large intestine, 599
of lower extremity, 594
lumbar, 596
mammary, 600
mediastinal, 600
. mesenteric, 600
of neck, 592
occipital, 590
parotid, 590
of pelvis, 596
deep, 596
popliteal, 595
radial, 593
sacral, 596
of small intestine, 599
of spleen, 599
of stomach, 599
submaxillary, 590
of thorax, 600
tibial, anterior, 595
ulnar, 593
of upper extremity, 588, 593
zygomatic, 590
Lymphatics, 81, 588
abdomen, 596, 598
arm, 594
bladder, 598
bone, 48
broad ligaments, 598
bronchial, 834
cardiac, 600
cerebral, 591
cervical, 592
chest, 600
clitoris, 598
cranium, 591
diaphragm, 600
efferent, 587
face, dcej), 591
pupcrlirlal, 591
Fiillopian tulics, 598
general aiiiitomy of, 81
gluteal region, 597
groin, 878
bead, 590
INDEX.
969
Lymphatics —
heart, 600
intercostal, 600
internal mammary, 600
intestines, 599
kidneys, 598, 845
labia, 598
lacteals, 599, 774
large intestine, 599
leg, 595
liver, 598, 786
lower extremity, 595
lung, 600, 834
memngeal, 591
mesenteric, 699
mouth, 591
neck, 592
nose, 591
nymphffi, 598
CESophagus, 601
ovaries, 598
pancreas, OOO
pelvis, 596, 598
penis, 597
perineum, 597
pharynx, 592
prostate, 598
radial, 594
rectum, 598
scrotum, 597, 860
small intestine, 599
spleen, 599
stomach, 599
structure of, 81
testicle, 598
thoracic duct, 589
thorax, 600
thymic, 601
thyroid, 601, 835
upper extremity, 593
uterus, 598
vagina, 598
valves of, 81
vessels of, 589
Lymphoid cellular tissue, 41
Lyra of fornix, 628
Macula cribrosa, 738
germinativa, 94
Magnuna (os) of carpus, 240
Malar bone, 180
articulations of, 181
attachment of muscles to,
181
development of, 181
Male organs of generation, 855
development of, 126,
128
Malleolus, external, 265
internal, 264
landmarks of, 941
Malleus, 735
suspensory ligament of, 736
Malpighi, capsule of, 841
pyramids of, 840
tuft of, 841
Malpighian bodies of kidney,
840, 841
corpuscles of spleen, 796
See Malpighi.
Mamma, 876
Mamma —
areola of, 877
development of, 115
ducts of, 877
lobules of, 877
mammilla of, 877
nerves of, 877
nipple, 877
structure of, 877
vessels of, 877
Mammary gland. See Mamma.
Mammilla of breast, 87 7
of kidney, 840
Manubrium of malleus, 735
of sternum, 207
Marrow of bone, 47
spinal, 604
Marshall, vestigial folds of, 120
Masseter, 352
Mastoid cells, openings of, 734
portion of temporal bone, 161
Matrix of nail, 87
MaxiUary bone, inferior. See
Inferior maxillary bone,
superior. See Superior
maxillary bone.
Meatus auditorius externus, 162,
731
internus, 163
of nose, inferior, 205, 713
middle, 172, 205, 712
superior, 171, 205, 712
urinarius, female, 868
male, 854, 856
Meckel's cartilage, 109
ganglion, 652
Mediastinum, 826, 827
anterior, 827
middle, 827
posterior, 826, 827
landmarks of, 925
testis, 862
Medulla oblongata, 610
corpora pyramidalia of, 611
fasciculi graciles of, 611
fissures of, 610
gray matter of, 613
lateral tract of, 611
olivary body, 611, 612
pyramids of, anterior, 611,
612
posterior, 611
restiform bodies, 611, 612
septum of, 613
structure of, 612
Medulla spinalis, 604. See
Spinal cord.
Medullary canal of bone, 47
membrane of bone, 47
substance of brain, 63
of kidney, 839
of suprarenal capsules, 847
velum, posterior, of cerebel-
lum, 633
Meibomian glands, 726
Membrana basilaris, 741
eboris, 753
fusca, 717
granulosa of retina, 717
limitans, 721, 722
nic titans, 727
Membrana —
obturatrix. 111
pupillaris, 719
sacciformis, 315
tectoria, 741
tympani, 735
secundaria, 733, 740
Membrane of aqueous chamber,
723
arachnoid, cerebral, 608
spinal, 603
basement, 93
blastodermic, 96
choroid, 716, 717
costo-coracoid, 401
of Corti, 741
crico-thyroid, 817
of Descemet, 718
fenestrated, 76
hyaloid, 723
hyoglossal, 710
interosseous, 313
Jacob's, 720
limiting, 721, 722
mucous, 92
Nasmyth's, 752
obturator, 442
pituitary, 712
pupillary, 719
of Reissner, 741
Schneiderian, 712
serous, 92
synovial, 93
thyro-hyoid, 206, 816
tubular, 62
vitelline, 94
Membranes of brain, 606
of spinal cord, 602
Membranous labyrinth, 748
portion of urethra, 853
semicircular canals, 743
zone, 742
Meninges, cerebral, 606
spinal, 602
Menisci, 45
Meroblastic ova, 95
Mesencephalon, 111
Mesentery, 764, 766
Mesocajcum, 766
Mesoclphale, 614
Mesocolon, ascending, 766
descending, 767
sigmoid, 767, 779
transverse, 764, 767, 779
Mesorchium, 866
Mesorectum, 764, 767, 780
Metacarpus, 241
development of, 244
peculiar bones of, 241
Metatarsus, 274
development of, 276
Milk teeth, 747, 749
Mitral valve, 808
Modiolus of cochlea, 739
Molar teeth, 748
Molecular layer of retina, 721
Monro, foramen of, 625, 628
Mons Veneris, 867
Monticulus cerebelli, 632
Morgagni, hydatid of, 1 26
liquor of, 723
970
INDEX.
Morsus diaboli, 873
Mouth, 745
landmarks of, 918
muscles of, 350
Mucoid cellular tissue, 41
Mucous membrane, 92
Miiller, duct of, 1 24
Multicuspidate teeth, 748
Muscle or Muscles, Descriptive
Anatomy of, 339
of abdomen, 385
abductor indicis, 425
minimi digiti of foot, 457
of hand, 423
poUicis of foot, 456
of hand, 421
accelerator urinae, 898
accessorius ad sacro-lumba-
lem, 3 79
orbicularis oris, 351
pedis, 457
of acromial region, 404
adductor bre vis, 439
longus, 439
magnus, 438
pollicis of hand, 423
of foot, 458
anconeus, 417
anomalus, 349
antitragicus, 731
ai'yta;no-epiglottideus infe-
rior, 819, 821
superior, 821
arytajnoideus, 820, 821
attollens aurcm, 344
attrahens aurem, 344
of auricular region, 344
azygos uvulse, 369
of back, 373
baslo-glossus, 364
biceps of arm, 408
of leg, 444
biventer cervicis, 381
of bladder, 851
brachial region, anterior, 411
413
posterior, 417, 418
brachialis anticus, 409
buccinator, 352
cerato-glossus, 339
cervlcalls ascendens, 3 79
descendens, 379
chondro-glossus, 364
clllarls, 345
ciliary of the eye, 719
circumflexus palati, 369
coc(;ygeus, 902
coclilearis, 741
complexus, 381
comjjressor narium minor,
349
nasi, 349
saccidl laryngis, 810, 821
urctlira;, 901
constrictor isthml fauclum,
365, 309
pharytigis inferior, 36C
mciliiis, 3G7
8n])ei-ior, 367
urctliriu, 901
coraco-brachlalis, 408
Muscle or Muscles —
eorrugator supercillll, 345
cranial region, 342
cremaster, 860, 865, 881
crico-arytasnoideus lateralis,
820, 821
posticus, 819, 821
crico-thyrold, 819, 821
crureus, 436
dartos, 860
deltoid, 404
depressor alse nasi, 349
anguli oris, 351
epiglottidis, 821
labli Inferloris, 351
diaphragm, 394
digastric, 362
dilatator naris anterior, 349
posterior, 349
of pupil, 719
of epicranial region, 342
erector clltoridis, 900
penis, 899
splnge, 379
of expiration, 394, 397
of external ear, 344
extensor brevls digltorum, 455
carpi radlalls brevior, 416
longlor, 415
ulnaris, 41 7
coccygis, 383
communis digltorum, 417
indicis, 419
longus digltorum, 447
minimi digiti, 417
ossis metacarpi pollicis, 418
primi internodll pollicis,
418
proprlus pollicis, 4.47
secundl internodii pollicis,
418
of eyeball, 346
of eyelids, 345
of face, 342
femoral region, anterior, 332
internal, 437
posterior, 444
fibular region, 452
flexor accessoi'Ius, 457
brevls digltorum, 456
minimi digiti of foot, 458
of hand. 423
pollicis of foot, 458
of hand, 422
carpi radlalls, 411
brevls, 412
profundus, 412
ulnaris, 412
digltorum profundus, 413
subliinis, 41 2
longus digltorum, 451
pollicis of loot, 450
of lumd, 414
ossis metacarpi ])nllicis, 421
profundus digitoi-uni, 413
sulilimis (ligitoruni, 412
of i'oot, 45.'i, 4 55
gastrocnemius, 448
gcrncilus ini'crior, 443
superior, 4 13
gcnio-hyo-glossus, 303
Muscle or Muscles —
genlo-hyoid, 362
of gluteal region, 439
gluteus maximus, 439
medlus, 440
minimus, 441
gracilis, 43 7
of hand, 420
of head and face, 341
helicis major, 731
minor, 731
Hilton's, 819
of hip, 432
humeral region, anterior, 407
posterior, 409
hyo-glossus, 364
ofhyoldbone, 359, 361
iliac region, 430
illacus, 431
illo-costalls, 379
infracostal, 393
infraspinatus, 405
of inspiration, 394, 399
intercostal, 392
external, 392
internal, 393
of intermaxillary region, 354
interossei, dorsal, 424, 459
palmar, 425
plantar, 459
intersplnales, 383
intertransversales, 383
kerato-glossus, 364
kerato-cricoideus, 819
labial, 349, 350
of larynx, 359, 361, 819
latlsslmus dorsi, 3 74
laxator tympani major, 736
minor, 736
of leg, 445
levator anguli oris, 350
scapulas, 3 76
ani, 901
glandulse thyroIdea3, 835
labli inferloris, 350
superloris, 350
alajque nasi, 349
proprlus, 350
menti, 350
palati, 368
palpebrae superloris, 346,
725
prostata;, 855, 902
levatores costarum, 393
lingualis, 364
of lip, 349, 350
of little finger, 423
longlsslmus dorsi, 381
longus colli, 3 71
of lower extremity, 429
lumbricales of foot, 457
of luuid, 4 24
masscter, 352
of mouth, 351
nudtifidus spina?, 382
niylo-liynid, 362
naso-lai)i;ilis, 351
of neck, 355
of nose, 7 1 1
oblI(pie. See Muscle, obli-
quus.
INDEX.
971
Muscle or Muscles —
obliquus ascendens, 387, 881
auris, 731
capitis inferior, 384
superior, 384
descendens, 385, 879
externus abdominis, 385,
879
internus abdominis, 387,
881
oculi inferior, 348
superior, 347
obturator externus, 443
internus, 442
occipito-frontalis, 342
omo-hyoid, 363
opponens minimi digiti, 424
poUicis, 422
orbicularis latus, 345
oi'is, 351
palpebrarum, 345, 726
of orbital region, 346
of palatal region, 368
of palate, 756
palato-glossus, 365, 369
palato-pliaiyngeus, 369
palmaris brevis, 423
longus, 412
of palpebral region, 343
pectineus, 437
pectoralis major, 399
minor, 401
of penis, 899
of perineum, female, 900
male, 898
peroneus brevis, 453
longus, 452
tertius, 447
of pharynx, 366
of pinna, 730
of plantar region, 455
plantaris, 449
platysma myoides, 356
popllteus, 450
prevertebral, 371
pronator quadratus, 414
radii teres, 411
psoas magnus, 431
parvus, 431
pterygoid, external, 355
internal, 354
pyramidalis abdominis, 391
nasi, 349
pyriformis, 441
quadratus femoris, 443
lumborum, 391
menti, 351
quadriceps extensor cruris,
435
radial region, 421
rectus abdominis, 390
capitis anticus major, 370
minor, 3 70
posticus major, 383
minor, 384
femoris, 435
lateralis, 371
oculi externus, 347
inferior, 347
internus, 347
superior, 346
Muscle or JMuscles —
sternalis, 401
thoracis, 393
retrahens aurem, 344
rhomboideus, 349
major, 376
minor, 376
ring, 719
risorius of Santorini, 352
rotatores spinte, 383
sacro-lumbalis, 379
sartorius, 434
landmarks of, 938
scalenus anticus, 372
medius, 372
posticus, 3 72
scapular region, anterior, 404
posterior, 405
semimembranosus, 445
semispinalis colli, 382
dorsi, 382
semitendinosus, 444
serratus magnus, 402
posticus inferior, 378
superior, 377
sole of foot, 455
soleus, 449
sphincter ani, external, 896
internal, 781, 896
of pupil, 719
vagince, 900
spinalis cervicis, 381
colli, 381
dorsi, 381
splenius, 378
capitis, 378
colU, 378
stapedius, 736
sterno-cleido-mastoid, 357
landmarks of, 921
sterno-hyoid, 359
sterno-mastoid, 357
stern o- thyroid, 360
stylo-glossus, 365
stylo-hyoid, 362
stylo-pharyngeus, 367
subanconeus, 410
subclavius, 401
subcrureus, 436
subscapularis, 404
supinator brevis, 418
longus, 415
supracostal, 393
supraspinales. 383
supraspinatus, 405
temporal, 353
tensor palati, 369
tarsi, 346
tympani, 734, 736
vagiuEe femoris, 434
teres major, 406
minor, 406
of thigh, 432, 437, 444
of thoracic region, anterior,
399
lateral, 402
of thorax, 399
of thumb, 421
thyro-arytasnoideus, 819, 820,
821,_
thyroepiglottideus, 821
Muscle or Muscles —
thyro-hyoid, 360
tibialis anticus, 446
posticus, 451
tibio-fibular region, anterior,
446
posterior, 448
of tongue, 363, 710
trachealis, 824
trachelo-mastoid, 381
tragicus, 731
transversalis abdominis, 388,
882
colli, 381
transversus auriculaj, 731
pedis, 459
perinei, 899
in female, 900
trapezius, 373
triangularis menti, 351
sterni, 393
triceps extensor cruris, 435
cubiti, 409
femoralis, 436
of trunk, 373
of tympanum, 736
of ulnar region, 423
of upper extremity, 398
triticeo-glossus, 821
of ureters, 851
of urethra, 898
vastus externus, 435
internus, 435, 436
vertebral region, anterior,
370
lateral, 372
zygomaticus major, 350
minor, 350
Muscles, General Anatomy of, 56
of animal life, 56
aponeuroses of. See Aponeu-
roses,
arrangement of fibres of, 57
bipenniform, 339
bloodvessels of, 60
cells, 59
development of, 116
fasciculi of, 56
fibrils of, 57
form of, 339
insertion of, 339
involuntary, 58
lymphatics of, 60
mode of connection with
bone, &c., 339
nerves of, 603
nomenclature of, 339
of organic life, 58
origin of, 339
penniform, 339
primitive fasciculi of, 56
fibrils of, 57
radiated, 339
sarcous elements of, 56
sheath of, 56
size of, 339
striped, 56
structure of, 56
tendons of, 340
unstriped, 58
voluntary, 56
972
INDEX.
Muscular tissue, 56
Muscularis mucosas, 59, 93
Musculi papillares of left Tsn-
tricle, 808
of right ventricle, 805
pectinati, in left auricle, 807
in right auricle, 804
Musculus. See Muscle.
Naboth, o-sTila of. 872
Nails, 87
chemical composition of, 87
general anatomy of, 87
lunula of, 87
matrix of, 87
root of, 87
structiu-e of, 87
Nares, anterior, 203
posterior, 203, 759
landmarks of, 919
septum of, 203, 712
Nasal bones, 1 74
articulations of, 174
development of, 174
cavities. See Nares.
landmarks of, 917
fossag, 203, 712
arteries of, 713
mucous membrane of, 712
nerves of, 713
veins of, 713
Nasmyth's membrane, 752
Nates of brain, 631
Navicular bone, 104, 272, 762
Neck, fasciae of, 355
glands of, 592
landmarks of, 920
lymphatics of, 592
muscles of, 355
triangle of, anterior, 358, 486
posterior, 358, 488
veins of, 538
landmarks of, 920
Nekton's line, 937
Nerve or Nerves, 60, 68, 637
Descriptive Anatomy of —
abducens, 641
accessory obturator, 686
acromial, 668
Arnold's, 661
articular, 677, 686, 688, 692,
695
auditory, 639, 744
auricular, of auricularis mag-
nus, 668
of auriculo-temporal, 655
posterior, from i'acial, G45
of second cervical, 6 70
of small occipital, 668
of vagus, 661
auricularis niagnus, 668
auriculo-temporal, 655
of braeliial j)li'xus, 671
of bronclii, 834
buccal, 655
of facial, 64G
cardiac, 700
cervical, 663
inferior, 700
niidille, 699, 700
of puouinogastric, 662, 6G.'i
Nerve or Nerves —
superior, 6 99, 700
thoracic, 663
cardiacus magnus, 700
minor, 700
carotid, 654, 659
cavernous, of penis, 706
cervical, 666
anterior, 667
branches of, 667
cardiac, 662
posterior, 6 70
supex'ficial, 668
cervico-facial, 645
chorda tympani, 644, 738
ciliary, long, 649
short, 650
circumflex, 6 73
clavicular, 668
coccygeal, 688, 689
cochlear, 744
communicans noni, 669
peronei, 693
of Cotunnius, 653
cranial, 637
origin of, 663
crural, 684
anterior, 687
cutaneous, of arm, external,
674
internal, 674
lesser internal, 675
of buttock and thigh, 692
of cervical plexus, 668
circumflex, 673
coccygeal, 689
crural, anterior, 687
dorsal of ulnar, 6 77
nerves, 680
dorsalis penis, 692
of frontal, 649
hemorrhoidal, inferior, 690
ilio-hypogastric, 684
ilio-inguinal, 684
of inguinal region, 878
intercostal, 681
internal, 674
of ischio- rectal region, 895
lateral of dorsal, 680, 682
of intercostal, 681
of liver, 786
lumbar, 682
median, 675
middle, 687
musculo -cutaneous, 674,
695
musculo-spiral, 679
obturator, 686
palmar, 675
of patella, 688
perineal, 690
peroneal, 695
plantar, 693
])()pliteal, external, 695
internal, G93
ra,(ljal, 6.S0
sacral, 689
sciatic, lesser, 693
Rinall, 6r;2
of tlii','li, external, 686
inlcnial, 6!)7
Nerve or Nerves —
middle, 687
of thorax, anterior, 681
lateral, 681
tibial, anterior, 695
jDOsterior, 693
ulnar, 678
dental, anterior, 652, 713
inferior, 656
of inferior dental, 656
posterior, 652
descendens noni, 647
digastric, from facial, 645
digital of foot, dorsal, 694
plantar, 694
of hand, dorsal, 6 78
palmar, median, 677
radial, 680
ulnar, 677
dorsal, 680
anterior branches of, 680
posterior branches of, 680
roots of, 680
of penis, 692
dorsi-lumbar, 682
dorsi-spinal, 682
of dura mater, 607
eighth pair, 658
of eyeball, 725
facial, 642
of auricularis magnus, 668
of femoral artery, 54 7
fifth, 647
first, 637
fourth, 641
frontal, 649
ganglionic branch of nasal,
649
gastric branches of vagus, 663
genital, 684
genito-crural, 684
giosso-pharyngeal, 658
gluteal, inferior, 692
superior, 690
gustatory, 656
of heart, 662, 700, 810
hemorrhoidal, inferior, 690
hepatic, 703, 786
hypogastric, 684
hypoglossal, 646
iliac, 684
ilio-hypogastric, 684
ilio-inguinal, 684
incisor, 656
inframaxillary, of facial, 646
infraorbital of facial, 645
infratrochlear, 650
intercostal, 680, 681
lower, 681
upper, 681
intercosto-humeral, 681
interosseous, anterior, 675
posterior, 680
ischiatic, great, 692
small, 692
Jacobson's, 659, 737
of kidney, 845
labial, 652
of labyrinth, 744
lacln-vnial, 648
of ivancisi, 624
INDEX.
973
Nerve or Nerves —
laryngeal, external, 662
inferior, 662
intei'nal, 662
recurrent, 662
superior, 662
of sympathetic, 699
lingual, 656
of glosso-pharyngeal, 6G0
lumbar, 682
branches of, 682
roots of, 682
lumbo-sacral, 683
of the lung, 834
malar branch of facial, 645
of orbital nerve, 651
masseteric, 655
mastoid, 668
maxillary, inferior, 654
superior, 650
median, 675
mental, 656
mixed, 637
of motion, 637
motor oculi, 640
musculo-cutaneous of abdo-
men, 686
inferior, 684
of arm, 674
from peroneal, 695
superior, 684
musculo-spiral, 679
mylo-hyoid, 656
nasal, from Meckel's gan-
glion, 653
of ophthalmic, 649, 713
from superior maxillary,
652
from Vidian, 654
of nasal fossae, 713
naso-iDalatine, 653, 713
ninth, 646
obturator, 686
accessory, 686
occipital of facial, 645
great, 670
small, 668
of third cervical, 670
occipitalis major, 670
minor, 668
oesophageal, 663
olfactory, 620, 637, 713
ophthalmic, 648
optic, 638
orbital, 651
relations of, 642
of superior maxillary, 651
palatine, 652
anterior or large, 652, 713
external, 653
middle, 653
posterior or small, 653
palmar cutaneous of median,
675
deep, 675
ulnar, 678
palpebral, 652
par vagum, 660
parotid, 656
pathetic, 641
perforans Casserii, 674
Nerve or Nerves —
pericranial, of frontal, 649
perineal, 690
superficial, 690
jieroneal, 694
landmarks of, 941
petrosal, great, 654
small, 643
superficial external, or
large, 643, 654
pharyngeal, of external laryn-
geal, 662
of glosso-pharyngeal, 659
of Meckel's ganglion, 654
of pneumogastric, 662
of sympathetic, 699
phrenic, 669
plantar, cutaneous, 693
external, 694
internal, 693
pneumogastric, 660
popliteal, external, 694
internal, 693
portio dura, 642
inter duram et mollem, 643
intermedia, 643
mollis, 639
pterygoid, 655
pterygo-palatine, 654
pudendal, inferior, 692
pudic, 690, 692
pulmonary, from vagus, 662
radial, 679
recurrent laryngeal, 662
to tentorium, 641
renal splanchnic, 703
respiratory, external, of Bell,
672
internal, of Bell, 669
sacral, 688
roots of, 688
saphenous, external, or short,
693
internal, or long, 688
sciatic, great, 692
small, 692
second, 638
of sensation, 637
seventh, 639, 642
sixth, 641
of special sense, 637
spermatic, 703
spheno-palatlne, 652
spinal, 67, 665. See Spinal
nerves.
accessory, 660
splanchnic, great, 701
lesser, 702
renal, or smallest, 702
splenic, 703
sternal, 668
stylo-hyoid of facial, 645
subclavian, 6 72
suboccipital, 666, 66 7, 6 70
subscapular, 673
superficialls colli, 668
supraclavicular, 668
supramaxIUary of facial, 646
supraorbital, 649
suprascapular, 672
supratrochlear, 649
Nerve or Nerves —
sympathetic, 696
branches of, 696
cephalic portion of, 650, 698
cervical portion of, 698
ganglia of, 696
lumbar portion of, 704
pelvic portion of, 704
thoracic portion of, 701
tarsal, 695
temporal, of auriculo-tempo-
ral, 655
deep, 655
of facial, 645
of orbital nerve, 651
tcmporo- facial, 645
teraporo-malar, 618
third, 640
thoracic, anterior, 673
cardiac, 663
long, 672
posterior, 672
thyro-hyoid, 647
thyroid, 699, 835
tibial, anterior, 695
posterior, 693
of tongTie, 710
tonsillar, 660
trifacial, 647
trigeminus, 647
trochlear, 641
tympanic of facial, 644
of glosso-pharyngeal, 659,
737
ulnar, 677
uterine, 706
vaginal, 706
vagus, 660
branches of, 661
ganglions of, 661
vestibular, 744
Vidian, 654, 713
of Wrisberg, 675
Nerve or Nerves, General An-
atomy of^ 68
afferent, 70
cells, 61
centrifugal, 70
centripetal, 70
cerebro-splnal, 69
junction of funiculi of, 69
neurilemma of, 69
origin of, 69
plexus of, 69
sheath of, 69
structure of, 69
subdivision of, 69
termination of, 70
corpuscles, 61
efferent, 70
fasciculi, 69
fibres, 62
motor, 70
of special sense, 637
sensory, 70
spinal, roots of, 665
sympathetic, 70, 696
Nerve hillocks, 73
tufts, 73
Nervous centres, development
of, 110
974
INDEX.
Nervous substance, 60
chemical analysis of, 64
microscopic appearance of, 6 1
Nervous system, 60, 602
of animal life, 6 1
cerebro-spinal axis, 602
cortical substance, 61
divisions of, 602
fibrous nervous matter, 60
ganglia, 61
gelatinous fibres of, 61
general anatomy of, 60
gray or cinerltious substance,
60
of organic life, 60
sympathetic, 61
tubular fibres of, 61
vesicular matter, 60
•white or medullary substance
of, 60
Nervus cardiacus magnus, 700
minor, 700
cutaneus patellas, 688
petrosus superficialis major,
654
superficialis cordis, 700. See
Nerve.
Neurilemma, 62, 69
of cord, 603
Neuroglia, 41, 64
Nidus hirundinis, 634
Nipple, 877
landmarks of, 922
Nodes of Ranvier, 69
Nodule of cerebellum, 633
Noduli Arantii, 805
Nose, 710
arteries of, 712
bones of, 174
bridge of, 174
cartilages of, 711
of septum of, 711
columna of, 710
development of, 115
fossae of, 203, 712
landmarks of, 917
meatuses of, 171, 712
mucous membrane of, 712
muscles of, 324, 711
nerves of, 712
veins of, 712
vibrissaj of, 700
Nostrils, 203, 710
landmarks of, 917
Notcli, cotyloid, 250
ethmoidal, 158
interclavicukir, 207
iiitcrcondyloid, 258
nasal, 157
pterygoid, 168
sacro-sciatic, greater, 248, 253
lesser, 2'18, 253
sigmoid, 188, 190
Rpliciif)-palatine, 184
supraorbital, 157, 202
mipiascajxilar, 220
Notochord, 9H, 100
Nuck, canal of, 866, 876
Nummular layer of i-i'liiia, 721
Nymj)liin, 868
lyMil)liatics of, 598
Occipital bone, 150
articulations of, 150, 291
attachment of muscles to,
154
development of, 153
structure of, 153
Occiput, arteries of, 480
Odontoblasts, 750, 753
ffisophagotomy, 761
Oesophagus, 760
lymphatics of, 601
structure of, 761
surgical anatomy of, 761
Olecranon, 228
landmarks of, 946
Olfactory bulb. See Bulb, ol-
factory.
nerve. See Nerve, olfactory.
Olivary bodies of medulla ob-
longata, 611, 612
Omenta, 766
Omentum, gastro-colic, 766
gastro-hepatic, 763, 766
gastro-splenic, 766, 794
great, 764, 765, 766
lesser, 763, 765, 766
sac of, 763
Opening, aortic, in diaphragm,
396
in left ventricle, 807
auriculo- ventricular, 803, 804,
806
caval in diaphragm, 396
of coronary sinus, 803
of inferior cava, 803
cESophageal in diaphragm, 3 96
pituitary, 108
of pulmonary artery, 804
veins, 806
saphenous 434, 889, 892
landmarks of, 936
of superior cava, 803
See also Orifice.
Operation for club-foot, 453
of laryngotomy, 824
of laryngo-tracheotomy, 824
of ligation of arteries. See
individual Arteries.
of lithotomy, 903
of cEsophagotomy, 761
of staphylorraphy, 370
for strabismus, 348
tracheotomy, 824
for wryneck, 359
Opcrcula of dental grooves, 755
Opisthotonos, 928
0])tic commissure, 166, 621, 639
lobes, 631
Ora serrata, 720
Orbicular bone, 736
Orbits, 202
arteri(!a of, 492
muscles of, 346
relation of nerves in, 642
Organ of Corti, 941
of (iiraldfes, 126
of JlosenmuUer, 125, 876
of sense, 707
Orifice, auriculo- vcnti-icnlar,
803, 804
cariliac, 76 7
Orifice —
oesophageal, of stomach, 76 7
pyloric of stomach, 767
of uterus, 871
of vagina, 867
See also Opening, Aperture,
Os, and Ostium.
Os calcis, 267
hyoides, 206
innominatum, 245
magnum of carpus, 240
orbiculare, 736
planum, 171
See also Bone.
uteri, 871
Ossa triquetra, 173
unguis, 179
Ossicles of ear, 735
Ossicula of tj^mpanum, 735
Ossification of bone, 51
intracartilaginous, 51
intramembranous, 51, 54
of spine, progress in, 140
Osteoblasts, 55
Osteoclasts, 54
Osteo-dentine, 751
Osteology, 46
Ostium abdominale of Fallo-
pian tube, 873
internum, 872, 873
uterinum, 872
Otoliths, 744
Outlet of pelvis, 253
Ovary, 874
corpus luteum of, 875
development of, 124
Graafian vesicles of, 874
ligament of, 876
lymphatics of, 598
nerves of, 876
ovisacs of, 875
shape, position, and dimen-
sions of, 874
situation of, in foetus, 125
stroma of, 874
tunica albuginea of, 874
vessels of, 876
Ovicapsules of Graafian vesicle,
875
Oviducts, 873
Ovisacs of ovary, 875
Ovida of Naboth, 872
Ovum, 94
discharge of, 875
discus ])roligerus, 94
fecundation of, 95
general anatomy of, 94
germinal spot, 98
vesicle, 98
holoblastic, 95
nu'soblastic, 05
vitelline membrane of, 98
yelk of, 98
zona 2)ellucida, 98
PACCniONTAN depressions, 155
Pacinian co!-pusclcs, 72
Palat(!, 756
arches of, 756
cleft, 370
de.veloj)nient of, 110
INDEX.
975
Palate —
hard, 756
muscles of, 368, 736
soft, 756
Palate bone, 182
articulations of, 184
attachment of muscles to,
184
development of, 184
Palm of hand, landmarks of,
949
Palmar arch. See Arch.
Palpation by rectum, 950
Palpebra3, 725
Pampiniform plexus of veins,
584, 861, 876
Pancreas, 791
development of, 122
duct of, 793
landmarks of, 933
structure of, 793
vessels and nerves of, 793
Papilla lacrymalis, 725, 728
spiralis, 741
Papillffi, conjunctival, 727
of kidney, 840
of skin, 85
of tongue, 708
circumvallata3, 708
conicce, 708
filiformes, 708
fungiformes, 708
maximas, 708
medias, 708
minimEe, 708
structure of, 709
of tooth, 747
Par vagum, 660
Parietal bones, 154
articulations of, 154
attachment of muscles to,
154
development of, 154
Parotid gland, 757
accessory portion of, 758
duct of, 758
landmarks of, 916
lymphatics of, 591
nerves and vessels of, 758
Parovarium, 125, 876
Pars intermedia, 869
Patella, 260
articulations of, 262
attachment of muscles of, 262
development of, 262
fracture of, 461
landmarks of, 939
Pecquet, cistern of, 589
reservoir of, 589
Pedicles of vertebra, 133
Peduncles of cerebellum, 635
of cerebrum, 621
of corpus callosum, 624
of pineal gland, 630
Pelvic fascia. See Fascia, pel-
vic,
bones. See Pelvis.
Pelvis, 251, 848
arteries of, 540
articulation of, 300
with spine, 299
Pelvis —
axes of, 254
boundaries of, 251, 848
brim of, 252
cavity of, 253, 848
diameters of, 253
false, 251
inlet of, 253
ligaments of, 299
lymphatics of, 596
male and female, differ-
ences of, 254
outlet of, 253
position of, 253
of viscera at outlet of, 902
true, 252
of kidney, 839, 846
Penis, 856
arteries of, 858
corpora cavernosa, 857
corpus spongiosum, 847
development of, 126
dorsal artery of, 542
nerve of, 692
vein, 582
glans, 856
lymplaatics of, 597, 859
muscles of, 899
nerves of, 692, 859
prepuce of, 856
suspensory ligament of, 856
Perforated space, anterior, 620
posterior, 621
Perforating fibres of bone, 49
Pericardium, 799
fibrous layer of, 800
relations of, 799
serous layer of, 800
vessels of, 801
vestigial fold of, 120
Perichondrium, 43
Perilymph, 743
Perimysium, 56
Perineal space, 897
Perineum, 897
abnormal course of arteries
in, 905
deep boundaries of, 89''
fascia, deep, 899, 900
superficial, 897
landmarks of, 934
lymphatics of, 598
muscles of, 898
in the female, 900
surgical anatomy of, 895
Perineurium, 62, 69
Periosteum, 47
of teeth, 751
Peritoneum, 763
folds of, 764
landmarks of, 930
lesser cavity of, 765
ligaments, 765
mesenteries, 764, 766
omenta of, 766
reflections of, 763
relations of, in hernia, 884
Pes accessorius, 627
anserinus, 643
hippocampi, 627
Petit, canal of, 724
Petrous portion of temporal
bone, 161
Peyer's glands, 7 76
Phalanges of ear, 742
of foot, 275
articulations of, 276, 338
development of, 276
of hand, 243
articulations of, 243, 322
development of, 243
Pharynx, 759
aponeurosis of, 760
arteries of, 481
development of, 120
muscles of, 366
opening of, 759
Phleboliths, 582
Pia mater of brain, 609
of cord, 603
testis, 862
Pigment, 43, 86
cells of iris, 719
Pigmentary layer of choroid,
717
Piles, external, 895
Pillars of external abdominal
ring, 387, 880
of diaphragm, 396
of fauces, 756
of fornix, 628
of palate, 756
Pineal gland, 630
peduncles of, 630
Pinna of ear, 729
cartilage of, 729
ligaments of, 730
muscles of, 730
nerves of, 731
structure of, 729
vessels of, 731
Pisiform bone, 238
Pit of stomach, 9 '29
Pituitary body, 621
development of. 111
Placenta, 105
Plasma, 33, 35
Plate, cribriform of ethmoid,
170
external pterygoid, 168
perpendicular, of ethmoid,
171
Platysma myoides, 356
Pleura, 826
cavity of, 826
costalis, 826
landmarks of, 925
parietal layer of, 826
pulmonalis, 826
reflections of, 826
vessels and nerves of, 827
visceral layer of, 826
Plexus, biliary, 787
choroid, 625, 636
interlobular, 787
intralobular, 788
lobular, 787
Plexus of Nerves, 69
aortic, 703
brachial, 671
cardiac, anterior, 701
deep, or great, 700
976
INDEX.
Plexus of Xerves —
superficial, 701
carotid, 698
external, 698
cavernous, 698
cerebral, 699
cervical, 66 7
branches of, 668, 670
posterior, 670
ccellac, 703
colic, left, 703
middle, 703
right, 703
coronary, anterior, 701
posterior, 701
cystic, 703
diaphragmatic, 702
epigastric, 702
facial, 699
gastric, 703
gastro-duodenal, 703
gastro-epiploic, 703
left, 703
hemorrhoidal, inferior,
706
superior, 703
hepatic,' 703
hypogastric, 703, 704
inferior, 704
ileocolic, 703
infraorbital, 652
lumbar, 683
magnus profundus, 700
meningeal, 699
mesenteric, inferior, 703
superior, 703
oesophageal, 661, 663
ophthalmic, 699
ovarian, 703
pancreatic, 703
panci-eatico-duodcnal,
703
patellar, 688
pelvic, 704
pharyngeal, 659, 699
phrenic, 702
prostatic, 706
pulmonary, anterior, 663
posterior, 6G1, 701
pyloric, 703
renal, 702
sacral, 690
sigmoid, 703
solar, 702
spermatic, 703
splenic, 703
suprarenal, 702
tonsillar, 660
tympanic, 657, 73 7
vaginal, 706
vertebral, 700
vesical, 706
ofVeins, 564
cliorold. See Choroid,
licinori-hoidal, 5H2
ovarian, 581, 876
pam])iiiiibrm, 5«1, 861,
876
pharyngeal, 568
pterygoid, 567
spermatic, 584, 861
Plexus of Veins —
uterine, 683
vaginal, 583, 789
vesico-prostatic, 682
Plica semilunaris, 72 7
Polar globules, 95
Pomum Adami, 814
landmarks of, 920
Pons hepatis, 786
Tarini, 621
Varolii, 610, 614
septum of, 614
structure of, 614
Popliteal space. See Space,
popliteal.
Pores of skin, 85
Portal system, 585
Portio dura of seventh nerve,
642
inter duram et mollem, 643
intermedia, 643
mollis, 639
Porus opticus of sclerotic, 714
Pott's fracture, 461
Pouches, laryngeal, 819
Poupai-t's ligament, 386, 880,
890
landmarks of, 930, 931, 936
Prffijoutium clitoridis, 868
Prejjuce, 856
Primitive groove, 98
trace, 98
Process or Processes, acromion,
221
alveolar, 178
angular, external, 157
internal, 157
auditory, 162, 164
basilar, 151
ciliary, 718
clinoid, anterior, 168
middle, 166
posterior, 166
cochleariform, 164, 734
condyloid, 188
coracoid, 222
coronoid, of lower jaw, 188
ofuliia, 230
ethmoidal, of inferior turbi-
nated, 185
falciform, 889
frontal, of malar, 180
funicular, 866
hamular, of lachrymal, 180
of sphenoid, ] 68
of helix, 730
of incus, 735
of Ingrassias, 168
jugular, 151, 153, 160
lachrymal, of inferior tui'bl-
nated bone, 185
malar, of superior maxillary,
177
mastoid, 161
landmarks of, 915
maxillary, of inferior turbi-
nated, 185
of malar l)one, 181
of palate bone, 183
mental, 186
nasal, 178
Process or Processes —
odontoid, 135
olecranon, 228
olivary, 166
orbital, of malar, 181
of palate, 183
palate, 176, 178
post-glenoid, 161
pterygoid, of palate bone, 183
of sphenoid, 168
sphenoidal, of palate, 184
spinous, of ilium, 247
of sphenoid, 167
of tibia, 263
of vertebras, 133
styloid, of fibula, 265
of radius, 234
of temporal, 165
of ulna, 231
supracondyloid, 946
transverse, of vertebrfe, 133
unciform, 240
of ethmoid, 171
vaginal of sphenoid, 167
of temporal, 160, 164
vermiform of cerebellum, 632,
633
zygomatic, 160, 181
Processus ad meduUam, 635
ad pontem, 635
ad testes, 631, 632
brevis, of malleus, 735
caudatus, 730
clavatus, 611
cochleariformis, 164, 734
e cercbello ad testes, 631, 635
gracilis, of malleus, 735
vaginalis, of testis, 866
Promontory of sacrum, 143
of tympanum, 733
Prosencephalon, 110
Prostate gland, 855
landmarks of, 935
lobes of, 855
muscle of, 855, 902
position of, 855, 902
secretion from, 856
structure of, 855
surgical anatomy of, 902
vessels and nerves of, 856
Protoplasm, 38
Protovertcbraj, 98, 107
Protuberance, frontal, 109
maxillary (fostal), 110
occipital, external, 150
internal, 151
landmarks of, 915
Pubes, 246, 248
articulations of, 251, 303
attachment of niusclcs to, 251
development of, 251
landmarks of, 930
structure of, 250
symi)liysls of, 249, 303
Pu(kmdum, 867
Pulley of superior oblique, 916
I'ulsc at wrist, 948
Pulp cavity of spleen, 797
of tooth, 754
Puncta lacrymalla, 725, 728
landmarks of, 917
INDEX.
977
Puncta —
vasculosa, G22
Pupil of eye, 719
dilator muscle of, 719
membrane of, 719
sphincter muscle of, 719
Pylorus, 767, 768
landmarks of, 932
Pyramid of cerebellum, 633
of thyroid gland, 834
of tympanum, 734
; of vestibule, 738
Pyramidal bone, 236
PjTamids, anterior, 612
decussation of, 612
of Ferrein, 843
of Malpighi, 840
posterior, 611
of spine, 147
QuADEiGEMiNAL bodies, 631
PtADius, 233
articulations of, 235
development of, 235
landmarks of, 947
muscles attached to, 235
Ramus of ischium, 249
of lower ja-w, 188
of pubes, 249
Eanvler, nodes of, 69
Raphe of corpus callosum, 624
of palate, 756
of perineum, 895, 934
of scrotum, 859
of tongue, 708
Rathke, lateral trabeculas of,
108
Receptaculum chyli, 589
Rectum, 780
coats of, 781
development of, 121
folds of, 782
landmarks of, 935
lymphatics of, 598
palpation by, 950
relations of, in female, 870
male, 781
structure of, 781
Region of abdomen, 385, 763
acromial, muscles of, 404
auricular, muscles of, 344
of back, muscles of, 373
brachial, anterior, muscles of,
411, 413
posterior, 417, 418
cervical, superficial, muscles
of, 356
cranial, 342
diapliragmatic, 394
dorsal, of foot, muscles of,
455
epicranial, muscles of, 342
epigastric, 7G3
femoral, anterior, muscles of,
432
internal, 43 7
posterior, 444
fibular, 452
foot, dorsum of, 455
sole of, 455
62
Region —
gluteal, muscles of, 439
groin, 763, 878
of hand, muscles of, 421
humeral, antei'ior, 407
posterior, 409
hypochondriac, 763
hypogastric, 763
iliac, muscles of, 430
infrahyoid, muscles of, 359
inguinal, 763, 878
intermaxillary, muscles of,
351
ischio-rectal, surgical anato-
my of, 895
laryngo - tracheal, surgical
anatomy of, 824
lingual, muscles of, 363
lumbar, 763
maxillary, inferior, muscles
of, 350
superior, muscles of, 350
nasal, muscles of, 349
orbital, muscles of, 346
palatal, muscles of, 368
palmar, muscles of, 424
palpebral, muscles of, 345
pectoral, muscles of, 399
of perineum, 897
pharyngeal, muscles of, 366
plantar, muscles of, 455
popliteal, 552
pterygo- maxillary, muscles
of, 354
pubic, 763
radial, muscles of, 415, 421
scapular, anterior, muscles of,
404
posterior, 405
Scarpa's triangle, 546
of skull, anterior, 201
lateral, 199
suprahyoid, muscles of, 361
temporo- maxillary, muscles
of, 352
thoracic, muscles of, 392
anterior, 399
lateral, 402
tibio-fibular, anterior, 446
posterior, 448
ulnar, muscles of, 423
umbilical, 763
vertebral, anterior, muscles
of, 370
lateral, 372
Reil, island of, 616
Reservoir of Pecquet, 589
of thymus, 836
Respu-ation, muscles of, 394,396
organs of, 814
development of, 122
Restiform bodies of medulla
oblongata, 611, 612
Rete mucosum, 85
testis, 863
Retina, 720
arteria centralis of, 495, 722
external layer of, 720
fovea centralis of, 720
granular or middle layer of,
721
Retina —
internal or nervous layer of,
721
Jacob's membrane of, 720
limbus luteus of, 720
membrana limitans of, 721,
722
nummular layer of, 721
radiating fibres of, 722
■ structure of, 721
yellow spot of, 720
Retinacula of ileo-cajcal valve,
779
Ribs, 210
attachment of muscles to, 214
common characters of, 211
development of, 214
false, 211
floating, 211
landmarks of, 923
ligaments of, 295- 305
peculiar, 212
rules for counting, 923
true, 211
vertebral, 211
vertebro-costal, 211
vertebro-sternal, 211
Ridge, internal occipital, 152
interosseous, of fibula, 266
of tibia, 263
mylo-hyoidean, 187
pterygoid, 167
superciliary, 156, 159
supraorbital, 202
temporal, 154, 157, 159
Rigor mortis, 60
Rima glottidis, 818
Ring, abdominal, external, 386
860
internal, 883
landmarks of, 931
crural, 892
femoral, 892
landmarks of, 926
fibrous, of heart, 808
Rod-granules of retina, 721
Rods of Corti, 741
Rolando, arciform fibres of, 613
fissure of, 616
tubercle of, 613
Rosenmiiller, organ of, 125, 876
Rostrum of corpus callosum, 623
of sphenoid bone, 167
Rotation, 282
Ruga3 of stomach, 770
of vagina, 871
Sac, dental, 754
lachrymal, 728
landmarks of, 917
of omentum, 766
Sacculus laryngis, 818
of vestibule, 743
Sacrum, 143
articulations of, 146
attachment of muscles to, 146
development of, 145
peculiarities of, 145
structure of, 145
Salivary glands, 757
structure of, 759
978
INDEX.
Santorlnl, cartilages of, 816
Sarcode, 38
Sarcolemma, 56
Sarcous elements of muscle, 57
Scala media, 741
tympani, 741
vestibuli, 741
ScaliE of cochlea, 739, 741
Scalp, arteries of, 914
muscles of, 342
density of, 914
Scaphoid bone of foot, 272
of hand, 236
Scapula, 218
articulations of, 223
attachment of muscles to,
223
deyclopment of, 222
landmarks of, 928
ligaments of, 307
muscles of, 404
structure of, 222
Scarfskin, 85
Scarpa's triangle, 546
Schindylesis, 281
Schneiderian membrane, 712
Schwann, white substance of,
62
Sclerotic, 714
Scrotal hernia, 885
Scrotum, 859
dartos of, 860
lymphatics of, 597, 860
nerves of, 860
septum of, 859
vessels of, 860
Sebaceous glands, 88
Segmentation of cells, 94
Sella turcica, 166, 194
Semen, 865
Semicircular canals, 739
membranous, 743
Semilunar bone, 236
Seminal ducts, 809
granules, 865
vesicles. See Vesiculas semi-
nal es.
Seminiferous tubes, 862
Senses, organs of, 707
Septum auricularuHi, 803
between bronchi, 823
crurale, 893
lucidum, 625, 62.
of medulla oblongata, 613
of nose, 185, 203', 712
cartilage of, 712
poctinii'ormc, 857
of pons Varolii, C14
scroti, 859
subarachnoid, 608
of tongue, 708
ventriculoniin, 804, 809
Serous membranes, 92
Sesamoid bones, 976, 950
Sheath of arteries, 73
crural, 891
femoral, 891
d<;ntal, 750
of muscles, 56
of nerves, 69
synovial, 2;-iO
Shin, 263
Shoulder-joint, 308
bones of, 215
landmarks of, 944
muscles of, 309, 404
relation of biceps tendon to,
330
vessels and nerves of, 309
Sigmoid flexure, 779
Sinus or Sinuses — •
of aorta, 465, 806
of brain, 571
cavernous, 572
cerebral, 571
landmarks of, 915
circular, 572
circularis iridis, 719
confluence of, 571
coronary, 587, 803
of Cuvier, 1 1 9
of dura mater, 571
ethmoidal, 172
frontal, 156, 158
landm£ft'ks of, 914
of heart, 802, 806
of jugular vein, 568
of kidney, 838
of larynx, 818
lateral, 672
of left auricle, 806
longitudinal, inferior, 571
superior, 571
maxillary, 177
nasal, 156
occipital, 572
petrosal, inferior, 573
superior, 573
placental, 104
pocularis, 853
prostatic, 126, 853
pulmonary, 806
of right auricle, 803
sphenoidal, 166
straight, 572
terminal, 117
transverse, 573
uro-genital, 124, 126
uterinus, 583, 873
of Valsalva, aortic, 465
pulmonary, 806
venous, 565
Skeleton, 131
Skin, anatomy of, 83
appendages of, 87
areolae of, 85
cells of, 86
corinm of, 84
cuticle of, 85
derma of, 84
d(!Vclopment of, 86, 115
epidermis of, 85
furrows of, 85
hairs, 87
lymphatics of, 86
muscuhir fibres of, 85
nails, 87
nerves of, 86
papiUary layer of, 85
pores of, 86
retc mucosum of, 85
sebaceous ghinds of, 88
Skin —
sudoriferous or sweat glands,
89
tactile corpuscles of, 68, 85
true, 84
vessels of, 86
Skull, 149
anterior region of, 201
base of, 192
bones of, 149
cerebral or internal surface,
192
aevelopment of, 108
external surface of, 192
fissures of, 173
fossa of, anterior, 192
middle, 194
posterior, 195
lateral region of, 199
sutures of, 191
tables of, 131
vertex of, 192
Skull-cap, 914
thickness of, 915
Socia jDarotidis, 758
Soemmering, foramen of, 720
Soft palate, 756
aponeurosis of, 756
arches of, 756
muscles of, 368, 756
pillars of, 756
Sole of foot, muscles of, 455
Somatome, 108
Somatopleure, 100
Space, antei'ior perforated, 620
axillary, 505
Haversian, 49
intercostal, 211
interglobular of dentine, 750
interpeduncular, 620
medullary, 49
popliteal, 257, 552
posterior perforated, 621
subarachnoidean, 603, 608,
609
Spermatic cord, 860
arteries of, 860
landmarks of, 931
lymphatics of, 861
nerves of, 861
relation of to femoral ring,
892
in inguinal canal, 860,
880
veins of, 861
Spermatozoa, 865
Sphenoid bone, 1 65
articulations of, 169
attachment of muscles to, 1 70
development of, 169
Sj)henoidal spongy bones, 169
turbinated bones, 169
Sphincter ani, external, 896
internal, 896
of the pujHl, 71 9
Spinal column, 132, 147. See
also Vertel)ra.
Spinal cord, 66, 602, 604
arachnoid of, G03
arrangement of gray and
wlilte matter In, (li^
INDEX.
979
Spinal cord — "
central canal of, 66
ligament of, 604
columns of, 66, 605
development of, 106, 112
dura mater of, 602
filum term in ale of, 604
fissures of, 605
foetal peculiarity of, 604
jTi'ay commissure of, 606
ligamentum dentatum of, 604
denticulatum of, 604
membranes of, 602
neurilemma of, 603
pia mater of, 603
structure of, 64, 605
white matter of, 64
Spinal nerves, 67, 665
arrangement into groups,
665
branches of, 666
ganglia of, GG6
origin of, 927
landmarks of, 927
roots of, anterior, 665
posterior, 665
Spine, 132. See Vertebra and
Process, spinous,
movements of, 927
ethmoidal, 165, 194
of ilium, 247
landmarks of, 930, 93 7
of ischium, 248
nasal, 157, 158
anterior, 179
posterior, 182
pharyngeal, 151
of pubes, 249, 930
of scapula, 220
of vertebrae, 32, 926
landmarks of, 926
Splanchnoplem-e, 100
Spleen, 793
artery of, 797
capillaries of, 797
colorless elements of, 795
development of, 122
fibrous elastic coat of, 794
fissure of, 793
liilum of, 793
landmarks of, 932
lymphatics of, 599, 798
Malpighian corpuscles of, 796
nerves of, 798
proper substance of, 795
serous coat of, 794
structure of, 794
suspensory ligament of, 794
trabeculas of, 794
veins of, 797
Spot, germinal, 95
of Wagner, 94
yellow, 720
Squamous portion of temporal
bone, 159
Stapes, 736
annular ligament of, 736
Staphylorraphy, 370
Steno's duct, 758
Sternum, 207
articulations of, 210
Sternum —
attachment of muscles to,
210
development of, 209
landmarks of, 922
ligaments of, 299
Stomach, 76 7
alteration in position of, 768
alveoli of, 770
cardia of, 767
cellular coat of, 769
curvatures of, 767
development of, 120
follicles of, 770
fundus of, 767
landmarks of, 932
ligaments of, 767
lymphatics of, 599, 770
mucous glands of, 7 70
mucous membrane of, 769
muscular coat of, 769
orifices of, 767
peptic glands of, 770
pyloric end of, 767
pylorus, 767, 768
serous coat of, 769
splenic end of, 767
structure of, 769
surfaces of, 767
vessels and nerves of, 770
Strabismus, operation for, 348
Strias laterales, 624
longitudinales, 624
of muscles, 58
Stroma of ovary, 874
Subarachnoid fluid, 609
septum, 603
space of brain, 609
of cord, 603
Sublingual gland, 759
duct of, 759
Submaxillary gland, 758
duct of, 758
Subpeduncular lobe of cerebel-
lum, 634
Sudoriferous glands, 89
Sulci of cerebrum, 615
Sulcus spiralis, 741
Supercilia, 725
Superior maxillary bone, 175
articulations of, 179
attachment of muscles to,
179
development of, 179
Suprarenal capsules, 847
development of, 124
vessels and nerves of, 848
Surgical anatomy —
of abdominal aorta, 525
air-passages, 824
anterior tibial, 556
arch of aorta, 467
axilla, 505
axillary artery, 508
base of bladder, 897
bend of elbow, 513
brachial artery, 513
common carotid artery, 474
iliac artery, 536
dorsalis pedis, 558
external carotid, 475
Surgical anatomy —
iliac, 544
eye, 348
facial artery, 480
femoral artery, 548
hernia, 886
hamstring tendons, 445
innominate artery, 470
inguinal hernia, 878
internal carotid, 491
iliac, 538
ischio-rectal region, 895
laryngo- tracheal region,
824
lingual artery, 477
of lower extremity, 460
oesophagus, 761
perineum, 895
popliteal artery, 553
posterior tibial, 560
prostate gland, 902
radial artery, 516
Scarpa's triangle, 548
of soft palate, 370
sterno-mastoid muscle, 359
subclavian artery, 498
superior thyroid, 476
talipes, 453
temporal artery, 482
thoracic aorta, 522
triangles of neck, 486
ulnar artery, 520
of upper extremity, 426
Sustentaculum tali, 267
Sutura, 281
dentata, 281
harmonia, 281
limbosa, 281
notha, 281
serrata, 281
squamosa, 281
vera, 281
Suture, basilar, 191
coronal, 156, 191
cranial, 190
ethmo-sphenoidal, 1 93
ethmoido-froutal, 193
frontal, 191
fronto-malar, 203
fronto- maxillary, 203
fronto-parietal, 191
fronto-sphenoidal, 193
intermaxillary, 202
internasal, 202
interparietal, 191
lambdoid, 153, 156, 191
malo-maxillary, 203
masto-occipital, 153, 191
masto-parietal, 191
naso-maxillary, 201
occipito-parietal, 191
petro-occipital, 153, 191
petro-sphenoidal, 191, 194
sagittal, 155, 191
spheno-parietal, 191, 194
spheno-temporal, 1 94
squamo-parietal, 191
squamo-sphenoidal, 191
squamous, 191, 194
temporal, 194
transverse, 191
980
INDEX,
Svallo-w's nest of cerebellum,
634
Sweat-glands, 89
Sylvius, aqueduct of, 63 G
fissure of, 616, 620
Sympathetic nerve. See IsTerve,
sympathetic.
Symphysis of jaw, 186
"pubis, 249
Synarthrosis, 280
Synovia, 279, 280
Synovial membrane, 92, 279
articular, 280
bursal, 280
vaginal, 280. See also indi-
vidual Joints.
Syntonin, 60
System, Haversian, 49
Tabatiere anatomique. 948
Tables of skull, 131
Tactile corpuscles of "Wagner,
71
Ttenia hippocampi, 626
semicircularis, 625
violacea, 635
Talipes, varieties of, 453
Tarsus, 267
articulations of, 269
development of, 276
Taste-corpuscles, 709
Teeth, 747
bicuspid, 748
canine, 748
cement of, 750, 751
classification of, 755
cortical substance of, 751
crown of, 747
crusta petrosa of, 751
cuspidate, 748
deciduous, 747
dentine of, 750
development of, 751
enamel of, 751
eruption of, 755
eye, 748
fang of, 747
growth of, 752
incisors, 747
intertubular tissue of, 750
ivory of, 750
milk, 747, 749
molar, 748
multicuspidatc, 748
papilla; of, 747
permanent, 747
pulp cavity of, 750
roots of, 747
structure of, 749
temporary, 747, 749
tuljuli of, 752
wisdom, 749
Tegmentum, 622
Temporal Ijone, 150
articulations of", 165
attachirient of muscles to,
165
development of, 168
mastoid j)ortioii of, I CI
petrous ])ortion of, 1 C I
squamous portion oi', 159
Temporal bone —
structure of, 168
Tendo Achillis, 448, 449
landmarks of, 941
oculi, 345
palpebrarum, 345
Tendon, 340
structure of, 340
central, of diaphragm, 396
conjoined, of internal oblique
and transversalis, 387,
881
cordiform, of diaphragm, 396
popliteal, landmarks of, 940
Tentorium cerebelli, 608
Testes, 631, 861
aberrant duct of, 863
coni vasculosi of, 863
coverings of, 859, 861
tunica albuglnea, 862
vaginalis, 861
vasculosa, 862
descent of, 865
development of, 126
gubernaculum, 865
lobules of, 862
lymphatics of, 598, 861
mode of descent of, 865
pia mater of, 862
rete of, 863
size and Aveight of, 861
structure of, 862
tubuli seminiferi of, 862
tunics of, 859, 861
vas deferens of, 863
vasa eSerentia of, 863
recta, 863
vasculum aberrans of, 863
vessels and nerves of, 860
Testes muliebres, 874
Testicles. See Testes.
Thalami optici, 622, 620
Thalamencephalon, 111
Theca vertebralis, 602
Thigh, bone of, 254
fascia of, 432
landmarks of, 936
muscles of, 432, 444
Thorax, 207, 799
base of, 799
bones of, 207
boundaries of, 799
cutaneous nerves of, 681
fascia; of, 399
lymphatics of, 600
muscles of, 399
openings of, 799
parts passing through upper
openings of, 799
viscera contained in, 799
Throat, landmarks of, 918
Tlnnub, articulations of, 322
landmarks of, 94
muscles of, 421
Thymus gland, 836
chemical composition of, 839
lobes of, 836
vessels and nerves of, 837
Tliyro-liyoid membrane, 817
Tliyroid'cartilagc, 814
landmarks of, 920
ThjToid gland, 834
chemical composition, 836
isthmus of, 834
lymphatics of, 601
pyramid of, 834
structure of, 835
vessels and nerves of, 835
Tibia, 262
articulations of, 264
attachment of muscles to, 264
development of, 264
fracture of, 461
landmarks of, 939, 941
Tomes' s fibres, 753
Tongue, 707
arteries of, 710
development of, 120
epithelium of, 709
fibrous septum of, 709
follicles of, 709
landmarks of, 918
mucous glands of, 709
membrane of, 708
muscular fibres of, 710
muscles of, 363
nerves of, 710
papillaj of. See Papillas
tip of, 708
Tonsils, 756
landmarks of, 919
nerves and Acssels of, 757
of cerebellum, 633
Tooth. See Teeth.
Torcular Heroj^hili, 152, 571
Trabecula3 of corjDus caverno-
sum, 857
of foetal skull, 108
lateral, of Kathke, 108
of spleen, 794
of testis, 862
Trace, primitive, 98
Trachea, 823
cartilages of, 823
glands of, 824
landmarks of, 921
relations of, 823
structure of, 823
surgical anatomy of, 824
vessels and nerves of, 824
Tracheotomy, 824
Trachoma glands, 727
Tract, lateral, of medulla, 611,
612
optic, 638
Tractus intermedio-lateralls, 67,
opticus, 638
Tragus, 729
Trapezium bone, 238
Trapezoid bone, 239
Triangle of Ilesselbach, 885
ini'erior carotid, 362, 487
of neck, anterior, 358, 486
posterior, 358, 488
surgical anatomy of, 486
occipital, 362, 488
Scarpa's, 546
sul)clavian, 362, 488
submaxillary, 488
superior carotid, 362, 487
Trigone, of bladder, 852
landmarks of, 934
INDEX.
981
Trigonum vesicae, 852
Trochanters, greater and lesser,
256
landmarks of, 937
Trochlea of humerus, 226
Trunk, articulations of, 285
Tube, auditory, 731
Eustachian, 734, 759
Fallopian, 873. See Fallo-
pian tube.
Tuber cinereum, 621
ischii, 249
Tubercle of clavicle, 216
conoid, 216
deltoid, 216
of femur, 256
genial, 187
genital, 126
of hyoid bone, 206
lachrymal, 178
laminated, of cerebellum, 633
of Lower, 803
for odontoid ligaments, 151
of Rolando, 613
of scaphoid, 236
of tibia, 263
of ulna, 230
of zygoma, 160
Tubercula quadrigemina, 631
Tuberculo cinereo, 613
Tubei-culum Loweri, 803
Tuberosities of humerus, great-
er and lesser, 225
of tibia, 264
Tuberosity of femur, 258, 259
of ischium, 249
maxillary, 176
of palate bone, 183
of radius, 233
of rib, 211
of tibia, 263
Tubes, bronchial, 823
structure of, in lung, 831
recurrent, of Henle, 842
Tubuli contorti, 842
dental, 750
of Ferrein, 843
galactophori, 877
of kidney, 842
lactiferi, 877
recti, 863
seminiferl, 862
uriniferi, 842
Tubulus centralis modioli, 740
Tuft, Malpighian, 841
vascular, of kidney, 841
Tunica adventitia, 75
albuginea, 862
of eye, 347
of ovary, 874
intima, 75
E,uyschiana, 717
vaginalis, 860, 866
3)ropria, 862
reflexa, 862
vasculosa testis, 862
Turbinated bone, inferior, 184
middle, 171
sphenoidal, 167, 169
superior, 171
Tutamina oculi, 725
Tympanic bone, 732
Tympanum, 732
arteries of, 737
cavity of, 732
membrane of, 735
mucous membrane of, 737
muscles of, 736
nerves of, 737
openings of, 733
ossicula of, 735
structure of, 735
veins of, 737
Tyson, glands of, 856
Ulna, 228
articulations of, 233
development of, 233
landmarks of, 947
muscles attached to, 233
Umbilicus, 104, 762
landmarks of, 929
Unciform bone, 240
Ungual bone, 179
Upper extremity, arteries of,
_ 495
articulations of, 303
bones of, 215
fascia of, 398
ligaments of, 304
lymphatics of, 593
muscles of, 398
nerves of, 671
surgical anatomy of, 426
veins of, 593
Urachus, 850, 851
Ureters, 839, 846
development of, 124
muscles of, 851
nerves of, 847
relations of, 846
structure of, 846
vessels of, 847
Urethra, female, 868, 869
male, 853
bulbous portion of, 854
caput gallinaginis of, 853
development of, 1 24
in the child, 936
landmarks of, 935
membranous portion of, 853
muscles of, 898
prostatic portion of, 853
sinus of, 853
rupture of, course taken by
urine in, 904
sinus pocularis of, 853
spongy portion of, 853
structure of, 854
verumontanum of, 853
vesicula prostatica of, 853
Urinary organs, 838
development of, 123
Uterus, 871
appendages of, 872
arbor vita3 of, 872
body of, 871
cavity of, 871
cervix of, 871
changes of form, &c., 893
during menstruation, 872
in old age, 872
Uterus —
after parturition, 872
during pregnancy, 872
at puberty, 872
development of, 126
in foetus, 872
fundus of, 871
ganglia of, 704
ligaments of, 871
lymphatics of, 598, 873
mouth of, 871
nerves of, 706, 872
shape, position, &c., of, 871
structure of, 872
vessels of, 872
Uterus masculinus, 853
Utricle of vestibule^ 743
Utriculus hominis, 126
Uvea, 719
Uvula of cerebellum, 033
of throat, 756
vesicas, 852
Vagina, 870
columns of, 871
development of, 124, 128
examination by, 951
lymphatics of, 598
orifice of, 868
Vagus. See Par Vagum.
Valley of cerebellum, 633
Valsalva, sinuses of, 465, 806
Valve or Valves —
aortic, 807
of Bauhin, 778
coronary, 587, 803
of cystic duct, 790
Eustachian, 583, 803
of gall-bladder, 790
of heart, 803-808
ileo-cffical, 778
of Kerkring, 7 73
of lymphatics, 81
mitral, 808
of right auricle, 803
semilunar, aortic, 807
pulmonic, 805
tricuspid, 805
of veins, 79
of Vieussens, 631
Valvula Bauhini, 778
Valvulse conniventes, 773
Vas aberrans, 863
deferens, 863
Vasa aberrantia of brachial ar-
tery, 512
afFerentia of lymphatic glands,
589
brevia arteries, 529
veins, 585
efferentia of testis, 863
of lymphatic glands, 589
intestini tenuis, 530
recta, 863
vasorum of arteries, 77
of veins, 80
Vascular system, changes in, at
birth, 812
general anatomy of, 75
peculiarities of, in foetus, 810
Vasculum aberrans, 863
982
INDEX.
Vein or Veins —
Descriptive Anatomy of^
564
of aljE nasi, 565
angular, 5G5
articular, of knee, 581
of jaw, 666
auditory, 744
am-icular, anterior, 566,
567
posterior, 567
axillary, 575
azygos, 578
basilic, 574
basi- vertebral, 579
of bone, 47
brachial, 575
bracliio-cephalic, 574
bronchial, 578, 834
buccal, 665, 567
cardiac, 586
anterior, 587
great, 586
posterior, 587
cardinal, 120
cava, inferior, 583
superior, 576, 577
cephalic, 674, 576
cerebellar, 670, 573
cerebral, 570, 5 73
cervical ascending, 569
deep, 569
superficial, 567
transverse, 568
choroid of brain, 570
circumflex iliac, 583
superficial, 581
condyloid, posterior, 569
coronary, 587
of corpora cavernosa, 869
of corpus spongiosum, 859
striatum, 570, 625
cystic, 586
deep, 564
dental, inferior, 567
digital of hand, 575
of diploe, 569
dorsal of penis, 582
dorsalis nasi, 565
pedis, 581
dorsi-spinul, 569, 678
epigastric, 582
superficial, 581
of eyeball, 725
facial, 565, 568
f(!moral, 58, 582, 892
frontal, 565, 569
of Galen, 570, 587, 625
gastric, 585
gastro-cpiploic, 585
gluteal, 583
iKMiioiTJioidal, 582
of head, 565
hepatic, 584, 786, 787, 789
iliac, common, 583
external, 582
internal, 582
iiio-lumbar, 583
innominate, 576, 577
intercostal, snp(!rior, 577
interlf)l)iilar, 789
Vein or Veins —
interosseous, of forearm,
575
intralobular, 787, 789
jugular, anterior, 568
external, 56 7
posterior, 568
internal, 56 7, 56.8
of kidney, 684, 845
labial, Inlerior, 565
superior, 566
laryngeal, 568, 577
lateral sacral, 583
lingual, 668
of liver, 584, 786, 789
longitudinal, inferior, 571
superior, 571
of lower extremity, 580
lumbar, 584
mammary, internal, 576
masseteric, 565, 567
mastoid, 567
maxillary, internal, 567
median, 574
basilic, 675
cephalic, 575
cutaneous, 575
mediastinal, 578
medulll-spinal, 679
meningeal, 56 7
menlngo - rachidian, 569,
679
mesenteric, 118
inferior, 585
superior, 585
nasal, 565
of neck, 565, 567
oblique, 587
obturator, 583
occipital, 56 7, 570
oesophageal, 678
omphalomesenteric, 118
ophthalmic, 572
ovarian, 584
palatine, 565, 567
palmar, deep, 575
palpebral, inferior, 565
superior, 565
pancreatic, 585
pancreatico-duodenal, 585
parotid, 566
pericardiac, 576
peroneal, 581
pharyngeal, 568
phrenic, 584
plantar, external, 581
internal, 581
popliteal, 581, 582
portal, 564, 585, 785, 786,
789
primitive, 118
proj'unda femoris, 582
pterygoid, 567
pudic, external, 581
internal, 583
piilirionary, 564, 587, 833
radial, 67'1, 5 75
rimine, 566
renal, 584, 845
6a<'ral, lateral, 583
niiddh', 583
Vein or Veins —
salvatella, 574
saphenous, external or
short, 581
internal or long, 580, 886
landmarks of, 943
sciatic, 683
spermatic, 584, 861
spheno-palatlne, 568
spinal, 578
longitudinal, 579
of spinal cord, 579
splenic, 585
stylo-mastold, 567
subclavian, 567, 576
eublobular, 787, 789
submaxillary, 566
submental, 566
superficial, 564
supraorbital, 565
suprarenal, 584
suprascapular, 568
sural, 582
systemic, 564
temporal, 666
deep, 567
middle, 666
anterior, 669
posterior, 670
temporo-maxillary, 56 7
of thorax, 573
of thyroid gland, 835
thymic, 576
thyroid. Inferior, 568, 579
middle, 568
superior, 668
tibial, anterior, 580, 581
posterior, 681
tracheal, 57 7
transverse cervical, 568
facial, 566
ulnar, anterior, 574
deep, 575
posterior, 574
umbilical, 813
of upper extremity, 573
vaginal, of liver, 789
vasa brevia, 585
ventricular, 670
of vertebrae, 579
vertebral, 569, 576, 5 78
Vidian, 568
General Anatomy of, 78
anastomoses of, 564
coats of, 78
development of, 118
muscular tissue of, 79
plexus of, 564. ^ee Plexus
of veins,
sinuses of. See Sinus,
structure of, 78
valves of, 79
vessels and nerves of, 80
See also Vena and Venic.
Velum inter])ositum, 625, 628
medullary, 633
pendulum palati, 756
Vena cava, fuctal, 119
inferior, 583
superior, 576, 577
corporis striati, 570, 625
INDEX.
983
Vena cava —
innominata, 568, 576
portse, 564, 585, 789
salvatella, 574
See also Vein.
Vense basis vertebrarum, 286,
579
comltes, 564, 573
cordis minimse, 803
corporis striati, 570, 625
Galeni, 570, 587, 625
interlobulares, of kidney, 845
minimse cordis, 810
rectas, 845
propria renales, 845
Thebesii, 587, 810
vorticosse, 717
See also Vein.
Venter of ilium, 247
of scapula, 218
Ventricle of Arantius, 612
of brain, third, 629
fourth, 635
fifth, 627
lateral, 624
of cerebellum, 635
of corpus callosuiTi, 623
foetal, of eye, 114
of heart, left, 807
right, 804
of larynx, 818
Vernix caseosa, 115
Vertebra dentata, 135
prominens, 136
Vertebrae, 132
articulations of, 285
attachment of muscles to, 142
cerA'ical, 133
coccygeal, 142
development of, 106, 140
dorsal, 137
, general characters of, 132
ligaments of, 285
lumbar, 139
movements of, 927
Vertebrte —
ossification of, 141
primitive^ 107
sacral, 142
spines of, 132, 926
landmarks of, 926
structure of, 140
Vertebral column. See Verte-
te'oe.
Vertex of skull, 192
Verumontanum, 853
Vesicle, auditory, 114
cerebral, 110
germinal, 94
Graafian, 874
ocular, 113
of Purkinje, 94
seminal, 864
umbilical, 105
Vesicula serosa, 102
prostatica, 853
Vesiculte seminales, 864
Vestibule of ear, 738
aqueduct of, 163, 738
of vulva, 868
Vestigial fold of pericardium,
120
Vibrissa3, 710
Vieussens, valve of, 631
Villi, 773
VIncula accessoria tendinum,
413
Viscera, abdominal, 763
landmarks of, 931
pelvic, 903
Vitelline duct, 105
membrane, 94
Vitellus, 94
Vitreous body, 723
humor of eye, 723
table of skull, 131
Vocal cords, 818, 819
inferior or true, 819
superior or false, 818
Voice, organs of, 814
Vomer, 185
alaj of, 185
articulations of, 186
development of, 186
Vortex of heart, 809
Vulva, 8G7
development of, 125, 127
Wag NEK, spot of, 94
tactile corpuscles of, 71
Waters, on the lung, 833
Watney on villi, 7 73
Wharton's duct, 758
jelly, 41, 105
White substance of brain, 60
of Schwann, 6 2
Willis, circle of, 502
Wings of sphenoid, 167. See
Alte.
Winslow, foramen of, 765
ligament of, 3 27
Wirsung, canal of, 793
Wisdom tooth, 749
Wolffian body, 123
duct, 123
Womb. See Uterus.
Wormian bones, 173
Wrisbei'g, cartilages of, 816
ganglion of, 701
nerve of, 6 75
Wrist-joint, 315
landmarks of, 947
Wry neck, oj)eration for, 359
Xiphoid appendix, 209
Y-SHAPED centre of acetabu-
lum, 250
Yellow spot of retina, 720
Yollc of ovum, 94
Zona jielluclda, 94
Zygoma, 180
THE END
CLASSIFIED LIST
OP
MEDICAL AND SURGICAL PUBLICATIONS
ISSUED BY
EiEItTI^ir O. XjEJL.
ANATOMY.
Allen's System of Human Anatomy, Including its Medical
and Surgical Relations. For the use of practitioners and
students of medicine. With an introductory chapter on
Histology. By E. 0. Shakespeare, M.D., Ophthalmologist
to the Philadelphia Hospital. In one large quarto vol-
ume, with several hundred original illustrations on litho-
graphic plates, and numerous wood-cuts in the text.
(Preparing.)
Wilson's System of Human Anatomy, General and Special.
Edited by W. H. Gobsiecht, M.D., Prof, of General and
Surgical Anatomy in the Med. College of Ohio. With 397
Illustrations on wood. In one large and handsome octavo
volume of over 600 large pages. Cloth, $1 00 ; leather,
$.5 00.
Smith & Horner's Anatomical Atlas, Illustrative of the
Structure of the Human Body. In one large imperial Svo.
volume, with about bOO pages. Cloth, $1 .00
Heath's Practical Anatomy, a Manual of Dissections. From
the second revised and improved London edition. Edited,
with additions, by W W. Kken, M D., Lecturer on Path-
ology in the JeflTerson Med. College, Philadelphia. In one
handsome royal 12mo. volume of 578 pages, and 217 illus-
trations. Cloth, $3 .'lO ; leather, $1 .oO.
Horner's Special Anatomy and Histology. Eighth edition.
In two volumes, 8vo., of about 1000 pages, with 320 wood-
cuts. Cloth, *6 00.
Bellamy's Student's Guide to Surgical Anatomy. In one
handsome royal 12mo. volume, with engravings. Cloth,
S2 25. (Lately P abashed.)
Cleland's Directory for the Dissection of the Human Body.
In one small volume, royal 12mo., of 182 pages. Clotti,
$1 25. (Just Issued.)
Hodge's Practical Dissections. Second edition, thoroughly
revised. In one neat royal 12mo. volume. Half bound,
$2 00.
Holden's Landmarks, Medical and Surgical. From the
second London edition. In one handsome volume, royal
12mo., of 128 pages. Cloth, 88 cents. (Now Rea y.)
Schaper's Course of Practical Histology. Being an Intro-
duction to the Use of the Microscope. In one handsome
royal 12mo. volume of 301 pages, with numerous illustra-
tions. Cloth, $2 00. [Just Issued.)
CoRNiL & Ranvier's Manual of Pathological Histology.
Tran-lated, with Notes and Additions, by E. 0. Shakes-
peare, M.D., Pathologist and Ophthalmic Surgeon to the
Philada. Hospital, etc. In one very handsome octavo
volume of about 600 pages, with over 300 illustrations.
(Preparing .)
Gluge's Atlas of Pathological Histology. Translated, with
Notes and Additions, by Joseph Leidt, M.D. In one
Volume, very large imperial quarto, with 320 copper-plate
figures, plain and colored. Cloth, $4 00.
PHYSIOLOGY.
Carpenter's Principles of Human Physiology. Edited by
Henry Power, M.I3. Lond., F.K C.S., Examiner in Natu-
ral Sciences, University of Oxford. A new American,
from the eighth revised and enlarged English edition,
with Notes and Additions by Franl;is G. Smith, M. D.,
Professor of the Institutes of Medicine in the University
of Pennsylvania, etc. In one vary large and handsome
ociavo volume of 10S3 pages, with two plates and 873 en-
gravings on wood. Cloth, $.) 50; leather, $6 50. (Just
lisued.)
Daltons Treatise on Human Physiology. Designed for the
use of students and practitioners of medicine. Sixth edi-
tion, thoroughly revised and enlarged. In one very beau-
tiful octavo volume of 830 pages, with 316 illustrations on
wood. Cloth, $5 50; leather, $6 50 (Lately Published.)
Kirke's Manual of Physiology. Edited by W. Morrant
Baker, M D , F.R.C.S A new American, from the eighth
and improved London edition. Witli about 250 illustra-
tions. In one large aud handsome royal 12mo. volurpe.
Cloth, $3 25 ; leather, $3 75. (Lately Issued.)
Hartshorne's Handoook of Anatomy and Physiology.
Second edition, revised In one royal 12mo. volume, with
220 wood-cuts. Cloth, $1 75. (Latdy Issued.)
Lehmann's Physiological Chemistry. In two octavo vol-
umes, of 1200 pages, with 200 illustrations. Cloth, $6 00.
Lehmann's Manual of Chemical Physiology, In one very
handsome octavo volume of 336 pages. Cloth, $2 25.
CHEMISTRY.
Fownes's Manual of Chemistry; Theoretical and Practical.
Revised and corrected by Henry Watts, B.A., F.R.S ,
author of "A Dictionary of Chemistry," etc. Wiih a
colored plate, and 177 illustrations on wood. A new
American, from the twelfth and enlarged London edition.
Edited by Robert Bridges, M.D. In one large royal 12mo.
volume of over 1000 pages. Cloth, $2 75; leather, $3 25.
(Just Ready.)
Attfield's Chemistry, General, Medical, and Pharmaceuti-
cal; including the Chemistry of the U. S. Pharmacopoeia.
A Manual of the General Principles of the Science, and
their application to Medicine and Pharmacy. Seventh
American, revised from the sixth English edition by the
author. In one^ very handsome l?mo. volume of 668
pages, with 87 illustrations. Cloth, $2 75 ; leather, $3 25.
(Just Issued.)
Bloxam's Chemistry, Inorganic and Organic. From the
second London edition. In one very handsome octavo
volume of 700 pages, with about 300 illustrations. Cloth,
$4 00; leather, $5 00. (Lately Issued.)
Clowes' Elementary Treatise on Practical Chemistry and
Qualitative Inorganic Analysis. Specially adapted for
Use in the Laboratories of Schools and Colleges and by
Beginners. From the second and revised English edition,
with about fifty illustrations on wood. In one very hand-
some royal 12mo. volume of 376 pages. Cloth, $2 50.
(Juft Ready. )
Galloway's Manual of Qualitative Analysis. From the
Fifth London Edition. In one neat 12mo. vol., with illus-
trations. (Shortly.)
Classen's Elementary Quantitative Analysis. Translated,
with Additions, by Edgar F. S.mith, A.M., Ph.D , Assist-
ant in Analytical Chemistry in the Towne Scientific
School, Univ. of Penna. In one handsome royal 12mo.
volume, with illustrations. (Shortly.)
Remsen's Principles of Theoretical Chemistry, with Special
Reference to the Constitution of Chemical Compounds.
In one handsome royal 12mo. volume of 232 pages. Cloth,
%1 50. (Lately Issued.)
WoHLER k Fittig's Outlines of Organic Chemistry. Trans-
lated, with Additions, from the eighth German edition, by
Ira Remsen, M.D., Ph.D., Professor of Chemistry and
Physics in Johns Hopkins University, Baltimore la one
handsome volume, royal 12mo., of 550 pages. Cloth, .'$3 00.
Bowman's Introduction to Practical Chemistry, Including
Analysis. Sixth American, from the sixth and revised
London edition. With numerous illustrations. In one
neat volume, royal 12mo. Cloth, $2 25.
Bowman's Practical Handbook of Medical Chemistry. Sixth
American, from the fourth and revised English edition.
In one neat royal 12mo. volume of 351 pages, with numer-
ous illustrations. Cloth, $2 25.
Knapp's Technology ; or Chemistry Applied to the Arts and
to i\lanufactures With American additions, by Prof.
Walter R. Johnson. In two very handsome octavo vol-
umes, with 500 wood engravings. Cloth, $6 00.
DICTIONARIES.
DnNGLisoN's Medical Lexicon ; A Dictionary of Medical
Science ; containing a concise explanation of the various
Subjects and Terms of Anatomy, Physiology, Pathology,
Hygiene, Therapeutics, Pharmacology, Pharmacy, Sur-
gery, Obstetrics, Medical Jurisprudence, and Dentistry.
Notices of Climate and of Mineral Waters; Formula for
Officinal, Empirical, and Dietetic preparations ; with the
Accentuation and Etymology of the Terms, and the
French and other Synonyraes — so as to constitute a
French as well as English Medical Lexicon. A new edi-
tion. Thoroughly revised, aud very greatly modified
and augmented. By Richard J. Dunglison, M.D. In
one very large and handsome royal octavo volume of
over 1100 pnges. Cloth, $6 50; leather, raised bands,
$7 50. (Lately Issued.)
HENRY C. LEA, Philadelphia.
2
Bobltn's Dictionary of the Terms Used in Medicine and
the Collateral Sciences. Revised, with numerous addi-
tions, by Isaac Hays, M.D., editor of the "American
Journal of the Medical Sciences " In one large royal
12mo. volume of over 500 double-columned pages; cloth,
$1 50; leather, $2.
MANUALS.
Hartshorne's Conspectus of the Medical Sciences; con-
taining Handbooks on Anatomy, Physiology, Chemistry,
Materia Medica, Practical Medicine, Surgery, and Obste-
trics. Second edition, thoroughly revised and improved.
In one large royal 12mo. volume of more than 1000 closely
printed pages, with 477 illustrations on wood. Cloth,
$4 25; leather, $5 00. (Lately Issued.)
Neill and Smith's Analytical Compendium of the Various
Branches of Medical Science; for (he use and examina
tions of students. In one large and handsomely printed
royal 12mo. volume of about 1000 pages, with 37-t wood-
cuts; cloth, $4; strongly bound in leatner, with raised
bands, $4 75.
Lddlow's Manual of Examinations upon Anatomy, Physi-
ology, Surgery, Practice of Medicine, Obstetrics, Materia
Medica, Chemistry, Pharmacy, and Therapeutics. To
which is added a Medical Formulary. Third edition,
thoroughly revised and greatly extended and enlarged.
With 370 illustrations. In one handsome royal 12mo.
volume of S16 large pages. Cloth, $3 25 ; leather, $3 75.
Taxneb's Manual of Clinical Medicine and Physical Diag-
nosis. Third American from the second London edition.
In one neat volume small 12mo., of about 375 pages.
Cloth, $1 50.
What to Observe at the Bedside and after Death in Medical
Cases. From the second London edition ; one volume
royal 12mo. Cloth, $1.
MATERIA MEDICA AND THERAPEUTICS.
Stille & Maisch's National Dispensatory: Embracing the
Chemistry, Botany, Materia Jledica, Pharmacy, Pharma-
codynamics and Therapeutics of the Pharmacopoeias of
the United States and Great Britain. For the use of physi-
cians and pharmaceutists. In one handsome octavo vol-
ume of about 1350 pages, with numerous illustrations.
(In Press.)
Stille's Therapeutics and Materia Medica ; a Systematic
Treatise on the Action and Uses of Medicinal Agents, in-
cluding their Description and History. Fourth edition,
revised and enlarged. In two large and handsome 8vo.
volumes of about 2000 pages. Cloth, $10; leather, $12.
(Lately Published.)
Farquharso.n''s Guide to Therapeutics. Edited, with Ad-
ditions, embracing the U. S. Pharmacopceia. By Frank
WooDBaRY, M.D. In one neat royal 12mo. volume of
over 400 pages. Cloth, iS2. (Now Ready.)
Parhish's Treatise on Pharmacy. Designed as a Text-book
for the student, aud as a Guide for the physician and
pharmaceutist. With many Formulae aud Prescriptions.
Fourth edition; thoroughly revised, by Tho.mas S, Wie-
GAND. In one handsome octavo volume of 977 pages,
with 2S0 illustrations. Cloth, $5 50; leather, $6 50.
(Lately Issued.)
Griffith's Universal Formulary; containing the Methods
of Prepariogand Administering Officinal and other Medi-
cines. The whole adapted to physicians and pharma-
ceutists. Third edition, thoroughly revised, with numer-
ous additions, by Joh.n M. Maiscu, Professor of Materia
Medica in the Philadelphia College of Pharmacy. In one
large and handsome octavo volume of about SOO pages.
Cloth, ijil oO; leather, !ji5 50. (Just Issued.)
PATHOLOGY.
Grbeh's Pathology and Morbid Anatomy. Second Ameri-
can, from thetliird and enlarged Eaglish edition. With
numerous illustrations. In one very handsome octavo
volume. Cloth, $2 75. {Just Issued )
FENWiCK'sStudent'sGuide to Medical Diagnosis. From the
third revised and enlarged Eaglish edition. With eighty-
four illustrations on wood. In one very handsome vol-
ume, royal 12rao. Cloth, $2 25. (Lattly Issued )
PRACTICE.
Bristowe's Treatise on the Theory and Practice of Medi-
cine. Edited, with additions, by Ja.mkh II. H(jtohin80.v,
M U., i'liyxlcian to the Peuua. Hospital. lu one large
and handriome octavo volume of over 1 llKi closely-printed
pageM Cloth, #5 .50 ; leatlier, $13 50. (Just Is.rued.)
Fi.i.NT'rf Treatise on the Principles and Practice of Medi-
cine; deitigued for the use of Htudonts an I |)ractltiouer8
of medlciuo. Fourth edillou, revised aud enlarged. In
CDC large and closely printed octavo volume of about
noo pags. Cloth, *ij ; or strongly bound in leather,
with rai.sed bands, ^1 . (Lately Issued,.)
Fli.stV E/4Kays on Couservatlvo Medicine and Kindred
Tojjics. lu one very liandNome royal 12mo. volume.
Cloth, $1 .•}8. (Just Ixvued.)
Watson's Lectures on the Principles and Practice of Phy-
sic. Delivered at King's College, London. A new Ameri-
can, from the fifth revised and enlarged Eusli^h edition.
Edited, with additions, and several hundred illustrations,
by Henry Hartshorne, M D , Professor of Hygiene in
the University of Pennsylvania. In two large Svo. vols.
Cloth, S9; leather, $11. (Lately Published.)
Hartshorne's Essentials of the Principles and Practice of
Medicine. A handy-book for students and practitioners
Fourth edition, revised and improved. With about 100
illustrations. In one handsome royal 12aQ0. volume of
about .550 pages. Cloth, $2 63; half-bound, $2 88. (Lately
Issued. )
Foi'hergill's Practitioner's Handbook of Treatment ; or,
the Principles of Therapeutics. In one very neat octavo
volume of about 575 pages. Cloth, $4 (Just Issuei.)
Fothergill's Antagonism of Therapeutic Agents, and What
it Teaches. Being the Fothergillian Prize Essay for 1S7S
In one neat volume, royal 12mo., of about 200 pages.
(Shortly)
Dunqlison, Forbes, Tweedie, and Conollt Cyolopjedia
of Practical Medicine: comprising Treatises on the Nature
and Treatment of Diseases, Materia Medica and Thera-
peutics, Diseases of Women and Children, Medical Juris-
prudence, etc. etc. In four super-royal octavo volumes,
of 3254 double-columned pages. Strongly and handsomely
bound iu leather, $15 ; cloth, $11.-
Barlow's Manual of the Practice of Medicine. With addi-
tions, by D. F. CoNDiE, M.D. One volume, octavo, 600
pages. Cloth, $2 50.
Davis's Clinical Lectures on Various Important Diseases.
Being a collection of the Clinical Lectures delivered in
the Medical Wards of Mercy Hospital, Chicago. Edited
by Frank H. Davis, M.D. Second edition, enlarged. In
one handsome royal 12mo. volume. Cloth. $1 75.
Tannisr's Manual of Clinical Medicine aud Physical Diag-
nosis. Third American from the second London edition.
In one neat volume, small 12mo., of about 375 pages.
Cloth, $1 .50.
Todd's Clinical Lectures on Certain Acute Diseases. In
one neat octavo volume of 300 pag>»s. Cloth, $2 50.
Sturqes' Introduction to Clinical Medicine. In one volume,
12mo. Cloth, $1 25.
Browne on Diseases of the Throat. (Shortly.)
Flint's Manual of Percussion and Auscultation ; of the
Physical Diagnosis and Diseases of the Lungs and Heart,
and of Thoracic Aneurism. In one handsome royal
12mo. volume. Cloth, $1 75.
Flint on Phthisis: its Morbid Anatomy, Etiology, Symp-
tomatic Events aud Complications, Fatality, and Prog-
nosis, Treatment, and Physical Diagnosis ; in a series of
Clinical Stu lies. In one handsome octavo volume $3 50.
Flint's Practical Treatise on the Physical Exploration of
the Chest and the Diagnosis of Diseases affecting the
Respiratory Organs. Second and revised edition. In one
handsome octavo volume of 595 pages. $4 50.
Gross's Practical Treatise on Foreign Bodies in the Air-
Passajes. Iu one volume, Svo., with illustrations, 468
pages. Cloth, $2 75.
Smith on Consumption ; its Early and Remediable Stages.
One volume, octavo, 254 pages. $2 25.
Williams on Pulmonary Consumption ; its Nature, Vari-
eties, aud Treatment. With an Analysis of One Thou-
sand Cases to exemplify its duration. In one neat octavo
volume of about 350 pages. Cloth, $2 50.
Fuller on Diseases of the Lungs and Air Passages: Their
Pathology, Physical Diagnosis, Symptoms, and Treat
meut. From the second and revised English edition. In
one octavo volume of about 500 pages. Cloth, $3 50
La Roche on Pneumonia. ,Oae volume, octavo, of 500
pages. Cloth, $3.
Slade on Diphtheria. In one 12mo. volume. Cloth, $1 2.5.
Flint's Practical Treatise on the Diagnosis, Pathology,
and Treatment of Diseases of the Heart. Second revised
and enlarged edition. In one octavo volume c)f 5.50 pages,
with a plate. Cloth, $1.
Walshe on the Diseases of the Heart and Great Vessels
Third American edition. In one volume, octavo, 420
pages. Cloth, $.3.
Brinton's Lecturtis on the Diseases of the Stomacli ; with
an Introduction on its Anatomy and Physiology With
illustrations. In one Svo. vol. of 300 pages. Cloth, $3 v!5.
CiiAMiiERs's Manual of Diet iu Health and Disease. 1 u one
handsome octavo volume. Cloth, $2 75. (.fust fssued.)
CHAiMUEKs's liestorative Medicine. An Harveian Annual
Oration. With two Sequela, lu ouo liaudsome 12mo.
volume. Cloth, $1.
Pavy's Treatise ou Food and Dietetics, Physiologically and
Tiierapeutically Considered In one handsome octavo
volume of nearly 600 pages. Cloth, i((4 75. (•/?*«( Issued.)
Paw's Treatise ou the Functiou of Digestion: its Dis.irders
aud Treatment. From the second Loudon edition. In
one haudsomo volume, small octavo. (Jlolh, $2.
Stokks'h Lectures on Fever, lu one neat volume of 264
pages. Cloth, $2 00.
LvoNs'H Treatise on Fever. In one octavo volume of 362
panes. Cloth, $2 25.
HENRY C, LEA, Philadelphia.
Hudson's Lectures on the Study of Fever. 1 vol. Svo.
Cloth, $2 50
La Roche on Yellow Fever, considered in its Historical,
> Pathological, Etiological, and Therapeutical Relations.
In two large and handsome octavo volumes of nearly
1.5C0 pages. Cloth, $7 00.
Todd's Cliaical Lectures on Certain Acute Diseases. In
one neat octavo volume of 300 pages. Cloth, $2 50.
Lincoln's Electro Therapeutics ; A Concise Manual of
Medical Electricity. In one very neat royal 12mo.
volume, with illustrations. Cloth, $1 oO. {Lately Is
sued.)
Bdmstead on the Pathology and Treatment of Venereal
Diseases, includiug the results of receat investigations
upon the subject. Third edition, revised and enlarged,
with illustrations. In one large and handsome octavo
volume of over 700 pages. Cloth, $5 00 ; leather, $ti 00.
(Just Issued. )
Cdllerier and Bdmstead's Atlas of Venereal Diseases.
Translated aad edited by Frek.man J. Bdmstead. In
one large imperial 4to. volume of 32S pages, double
columns, with 26 plates, containing about l.iO figures,
beautifully colored, many of them the size of life.
Strongly bound in cloth, §17 00; also, in tlve parts,
stout wrappers for mailing, at S3 00 per part.
Lee's Lectures ou Syphilis, and on some Forms of Local
Disease affecting principally the Organs of Generation.
In one handsome octavo volume of 246 pages. Cloth,
$2 2.") (Lately Issue-i )
HfcL on Syphilis and Local Contagious Disorders. In
^ne handsome Svo. volume. Cloth, $3 2.5.
Fox's Epitome of Skin Diseases, with Formula. For stu-
dents and practitioners. la one handsome 12mo. vol-
ume of 120 pages. Cloth, $1 00. (fust Issued.)
Wilson's Student's Book of Cutaneous Medicine and Dis-
eases of the Skin. In one very handsome royal 12mo.
volume. $3 50.
Nrligan's Atlas of Cutaneous Diseases. In one handsome
■4to. volume, with exquisitely colored plates, etc., pre-
senting about 100 varieties of disease. Cloth, $5 50.
Hillier's Handbook of Skin Diseases, for students and
practitioners. Second American edition. In one royal
]2mo. volume of 358 pages, with illustrations. Cloth,
$2 23.
OBSTETRICS.
Playfair's Treatise on the Science and Practice of Mid-
wifery. Second American, from the second and revised
English edition. Edited, with additions, by Robert P.
Harris, M.D. In one handsome octavo volume, with
numerous illustrations. (Preparing.)
Leishman's System of Midwifery, including the Diseases
of Pregnancy and the Puerperal State. Second Ameri-
can, from the second and revised English edition, with
additions by J S. Paeirt, M.D , Oostetrician to the
Phila. Hospital. In one large and very handsome oc-
tavo volume of nearly SOO pages, with about 200 illus-
trations. Cloth, $5 ; leather, 16. (Lately Issued.)
Hodbe's Principles and Practice of Obstetrics. Illustrated
with large lithographic plates jontaining 159 figures
from original photographs, and with numerous wood-
cuts. In one large and beautifully printed quarto vol-
ume of 350 double-columned pages. Strongly bound in
cloth, SU.
Hodse's Principles and Practice of Obstetric Medicine
and Surgery, in reference to the Process of Parturition
A new and enlarged edition, thorougl)ly reviied bj the
author. With additions by W. V. Keating, M.D.. Pro-
fessor of Obstetrics, etc., in the Jefferson Medical Col-
lege, Philadelphia. In one large and handsome imperial
octavo volume of 650 pages, strongly bound in leather,
with raised bands ; with 64 beautiful plates, and numer-
ous wood-cuts in the text, containiuf in all nearly 200
large and beautiful figures. Leather, $7.
Wests Lectures on the Dieeases of Infancy and Child-
hood. Fifth American, from he sixth revised and en-
larged English edition. In one large and hiuosome
octavo volume of 678 pages. Cloth, $t 50 ; leather, $5 50.
(Lately Iss'i.e'i )
Tanner on the Signs and Diseases of Pregnancy. First
American from the second and enlarged English edition.
With 4 colored plates aad illustrations on wood. In
one handsome octavo volume of about 500 pagss. Cloth,
$4 25.
Parry on Extra-Uterine Pregnancy; its Clinicil History,
Diagnosis, Prognosis, and 'Treatment In one handsome
octavo volume of 274 pages. Cloth, $2 oO. (Lately Is-
sued )
Swayne's Obstetric Aphorisms for the use of Students
Commencing Midwifery Practice. Second Amerisan, from
the fifth and revised London edition, with addititus, by
E. R. HuTCHiNs, M.D. With illustrations. In one neat
12mo. volume. Cloth, •$! 25. (LatHy Issued.)
Rigby's System of Midwifery. Second American edition.
One volume, octavo, 422 pages. Cloth, $2 50
Winckel on the Pathology and Treatment of Childbed. A
trea ise for physicians and students. From the second
German edition, with additions by the author. Trans-
lated by Jame-! Read Chadwick, M.D., Clinical Lecturer
on Diseases of Women in Harvard University. In one
handsome octavo volume. Cloth, $4. (Lately Issued )
Montgomeky's Exposition of the Signs and Symptoms of
Pregnancy With 2 exquisite colored plates, and nu-
merous wood-cuts. In one volume, 8vo., of nearly 600
pages. Cloth, $3 75.
Chorchill on the Theory and Practice of Midwifery. With
notes and additions by D. Francis Condie, M.D. With
194 illustrations. In one very handsome octavo volume
of nearly 700 pages. Cloth, $4 00 ; leather, $5 00.
Churchill's Essays on the Puerperal Fever, and other
Diseases peculiar to Women. One volume, Svo., of 450
pages. Cloth, $2 .50.
Meigs on the Nature, Signs, and Treatment of Childbed
Fever One volume, Svo., of nearly 365 pages. Cloth,
$2 00.
GYN.S:COLOGY.
Thomas's Practical Treatise on the Diseases of Women.
Fourth edition, enlarged and thoroughly revised. In
one large and handsome octavo volume of 800 pages,
with 191 illustrations. Cloth, $5 00 ; leather, $6 00.
(Just Issued. )
Barnes's Clinical Exposition of the Medical and Surgical
Diseases of Women. Second American, from the second
enlarged and revised English edition. In one handsome
octavo volume, with many illustrations. (In Press.)
Chadwick's Manual of the Diseases Peculiar to Women.
In one neat volume, royal 12mo., with illustrations.
(Preparing.)
West's Lecturfs on the Diseases of Women. Third Amer-
ican, from the third London edition. In one neat octavo
volume of about 550 pages. Cloth, S3 75 ; leather, $4 75.
Hodge on Diseases Peculiar to Women ; including Dis-
placements of the Uterus. With original illustrations.
Second edition, revised and enlarged. In one beautifully
printed octavo volume of 531 pages. Cloth, $4 50.
Ashwell's Practical Treatise on the Diseases Peculiar to
Women. One volume Svo., 528 pages. Cloth, $3 50.
Dewee.-3's Treatise on the Diseases ol Females. With illus-
trations. In one Svo. vol. of 536 pages, with plates.
Cloth. $3 00.
DISEASES OF CHILDREN.
Smith's Practical Treatise on the Diseasts of Infancy and
Childhood. Third edition, enlarged and thoroughly
revised. With illustrations on wood. In one handsome
Svo. volume of 726 pages. Cloth, $5 00', leather, $6 00.
(Just Issued.)
West's Lectures on the Diseases of Infancy and Child-
hood. Fifth American from the sixth revised and en-
larged English edition. In one large and handsome
octavo volume of 678 pages. Cloth, $4 50 ; leather, $5 50.
(Lately Issued.)
West on some Disorders of the Nervous System in Child
hood. In one volume, small 12mo. Cloth, $1 00.
Smith's Practical Treatise on the Wasting Disease of la-
fancy and Childhood. In one Svo. volume. Cloth, -$2 50.
OPHTHALMOLOGY AND OTOLOGY.
Wells' Treatise on Diseases of the Eye. Third American,
from the fourth and revised London edition, with addi-
tions ; illustrated with numerous engravings on wood,
and 6 colored plates. Together with selections from the
test-types of Jaeger and Suellen. In one large and very
handsome octavo volume. (Preparing )
Carter's Practical Treatise on the Diseases of the Eye.
Edited, wi-.h test-types and additions, by John Green,
M.D.(o St. Louis, Mo). In one handsome octavo volume
of about .500 pages, and 124 illustrations. Cloth, $3 75.
(Just Issued.)
Browne s How to Use the Ophthalmoscope. Being ele-
mentary instructions in Ophthalmoscopy, arranged for
the use of students. In one small volume, royal 12mo.,
of 1'20 pages, with 35 illustrations. Cloth, $1 00. (Norn
Ready. )
Laurence's Handy-Book of Ophthalmic Surgery, for the
use of practitioners. Second edition, revised and en-
larged. With numerous illustrations. In one very
hanosome octavo volume Cloth, $3 00.
Lawson on Injuries to the Eye, Orbit, and Eyelids, their
Immediate and Remote Effects With about 100 illustra-
tions. In one handsome Svo. volume. Cloth, $3 50.
Burnett on the Ear ; its Anatomy, Physiology, and Di -
eases. A practical treatise for the use of medical students
and practitioners. In one handsome octavo volume ot
615 pages, with 87 illustrations. Cloth, $4 50; leather,
$5 50. (Just Ready.)
HENRY C. LEA, Philadelphia.
DISEASES OF THE URINARY ORGANS.
Gross's Practical Treatise on the Diseases, Injuries, and
Malformations of the Urinary Bladder, the Prostate Gland,
and the Urethra. Third edition, thoroughly revised by
Samuel W. Gross, M.D , Attending Pnysician to the
Philadelphia Hospital. In one handsome 8vo. vol. of 574
pages, with 170 illus. Cloth, .$1 50. [Jii^t J/isued.)
Thompson's Lectures on Diseases of the Urinary Organs
Wiiih illustrations on wood. Second American, from the
third English edition. In one neat octavo volume. Cloth,
•$2 25. {Just Ixsned.)
Thomp.^on on the Pathology and Treatment of Stricture of
the Urethra and Urinary Fistula. With plates and wood-
cuts. From the third and revised English edition. In
one very handsome octavo volume. Cloth, $S 50.
Tho.mpson on the Diseases of the Prostate, their Pathology
and Treatment. Fourth edition, revised. In one very
handsome octavo volume of 355 pages, with thirteen
plates, plain and colored, and illustrations on wood.
Cloth, .$3 75.
Roberts's Practical Treatise on Urinary and Renal Diseases,
including Urinary Deposits. Illustrated by numerous
cases and engravings. Second American, from the second
revised and enlarged London edition. In one large and
handsome octavo volume of 616 pages, with a colored
plate. Cloth, $i oO. {Lately Published.)
Basham on Renal Diseases: a Clinical Guide to their Diag
nosis and Treatmenc. With illustrations In one neat
royal 12mo. volume of 30-1 pages. Cloth, $2 00.
DISEASES OF THE NERVES AND MIND.
Hamilton on Nervous Diseases: their Description and
Treatment. In one handsome octavo volume of 512 pages,
with 53 illusi^ralions. Cloth, $3 50. {Just Ready )
Charcot on the Nervous System. Publishing in the Medi-
cal News and Library, commencing July, 1S7S
Blandford on Insanity and its Treatment: Lectures on the
Treatment, Medical and Legal, of Insane Patients. With
a summary of the laws in force in the United States on
the confinement of the insane. By Isaac Ray, M.D. In
one very handsome Svo vol. of 471 pages. Cloth, $3 25.
.To.NEs's Clinical Observations on Functional Nervous Dis-
orders. Second American editiou. In one handsome
octavo volume of 348 pages. Cloth, $3 25.
Tube's Illusirations of the Influence of the Mind upon the
Body in Health and Disease. Designed to illustrate the
Action of the Imagination. In one handsome octavo
volume of 416 pages. Cloth, $3 25. (Just Issued )
SURGERY.
Erichsen's Science and Art of Surgery, being a Treatise on
Surgical Injuries, Diseases, and Operations. Carefully
revised by the author from the seventh and enlarged
English edition. Illustpated by 862 engravings on wood.
In two large and beautiful octavo volumes of nearly 2000
pages. Cloth, ifeS.. 00; leather, $10 .50. {Now Heady.)
Gross's System of Surgery; Pathological, Diagnostic, The-
rapeutic, and Opei alive. Illu.strated by upwards of 1400
engravings. Fifth edition, carefully revised and im-
proved. In two large and beautifully printed imperial
octavo volumes of about 2.300 pages. Strongly bound in
leather, with raised bands, $l'> 00. {Just Issued.)
Stimson's Manual of Operative Surgery. In one very hand-
come royal r2mo. volume of about 500 pages, with .332
illustrations. Cloth, $2 50. {Just Ready.)
Bryant's Practice of Surgery. Second American, from the
second and revised English edition. With over 500 en-
gravings on wood. In one large and very handsome oc-
tavo vi^lume of aVjout 1000 pages. {Shortly )
IIoi.mkk's Surgery, its Principlct and Practice. In one large
and handsome octavo volume of nearly 1000 pages, with
411 illuKtralions on wood. Cloth, *6 00 ; leather, $7 00.
{Ju.ft Issued.)
Dkiiitt'k Principlosand Practice of Modern Surgery. From
tlie eighth enlarged and improved London edition. Illus-
trated with 432 wood engravings In one very handsome
octavo volume of nearly 700 large and closely printed
pages. Cloih, #4 00; leather, lHo 00.
Ha.milto.v'k I'raciical Treatise <>a Fractures and Disloca
tioDh. Fifth edition, revised and improved. Illustiated
with .3J4 wood-culu. In one large and handsome octavo
volume of 831 pages. Cloth, i|!.'; 70 ; leather, $6 75. {Lately
Issued.)
Ashhprst's Principles and Practice of Surgery. Second
edition, revised. In one large and handsome Svo. vol. of
about 1000 pages, with nearly 550 illustrations. {Shortly.)
Gossklin's Clinical Lectures on Surgery. Delivered at the
Hospital of La Charite. Translated from the French by
Lewis A. Stimson, M.D., Surgeon to the Presbyterian
Hospital, New York. With illustrations. In one neat
octavo volume of about 390 pages. Cloth, $2 50. (Now
Ready.)
Sargent on Bandaging and Other Operations of Minor Sur-
gery. In one 12mo. volume of 383 pages, with 184 illus-
trations. Cloth, $1 75.
Skey's Operative Surgery. In one volume, octavo, of 650
pages ; with about 100 wood-cuts. Cloth, $3 25.
Cooper's Lectures on the Principles and Practice of Sur-
gery. In one volume, octavo, 7.50 pages. Cloth, -$2.
Gibson's Institutes and Practice of Surgery. Eighth edi-
tion, improved. With 34 plates. In 2 vols. 8vo., about
lOCO pages. Leather, raised bands, $6 50.
The Principles and Practice of Surgery. By William
Pirrie, F.R.S.E.. Professor of Surgery in the University
of .Aberdeen, Edited by Jon.v Neill, M.D., Professor of
Surgery in the Penua. Medical College. In one Svo. vol.
of 780 pages, with 316 illustrations. Cloth, $3 75
Miller's Principles of Surgery. In one large Svo. vol. of
700 pages, with 340 illustrations. Cloth, $3 75.
Miller's Practice of Surgery. In one large octavo volume
of nearly 700 pages, with 364 illustrations. Cloth, $3 75.
MEDICAL JURISPRUDENCE.
T.\tlor's Medical Jurisprudence. Seventh American edi-
tion. Edited by John J. Reese, M D., Professor of Medi-
cal Jurisprudence in the University of Pennsylvania, la
one large octavo volume of nearly 900 pages. Cloth, $5 ;
leather, $8.
Taylor's Principles and Practice of Medical Jurisprudence.
Second edition, revised, with numerous illustrations. In
two large octavo volumes. Cloth, $10 ; leather, $12.
Taylor on Poisonsin Relation to Medical Jurisprudence and
Medicine. Third American, from the third revised Eng-
lish edition. In one large octavo volume of 788 pages,
and 104 illustrations. Cloth, $5 50 ; leather, $6 50. (Just
Issued.)
PERIODICALS.
The American Journal of the Medical Sciences. Quarterly.
Per annum, $5 00.
The Monthly Abstract of Medical Science. Monthly. Per
anuum, in advance, $2 60.
The Medical News and Library. Monthly. Per annum,
in advance, $1 00.
The American Journal of the Medical ) „
Science.s ( '^f' *""T-'oo
The Medical News and Library S advance, il,o 00.
The American Journal of the Medical "j
Sciences ! Per annum, in
The Monthly Abstractof.MedicalScience. [advance, $6 00.
The Medical News and Library J
The Obstetrical Journal of Great Britain and Ireland, vrith
an American Supplement. Monthly. Per annum, in
advance, $5 00.
MISCELLANEOUS.
A Century of American Medicine. 1776-1876. By Drs E.
H. Clarr>:, H J. Biqelow, S. D. Gross, T. G. Thoma.s,
J. S. BiLM.VHS. In one very handsome 12mo. volume of
about 350 pages. Cloth, $2 25. {.lust Issued.)
Carpi5nti;r"8 Prize Essay on the Use of Alcoholic Liquors
in Heallli and Disease In one neat 12mo. volume of 178
pages. Cloth, 60 cents.
Holland's Medical Notes and Reflections. One Svo. volume
of .500 pag.'S. Cloth, $3 50.
Lea's Superstition and Force: Essays on the Wager of
Law, the Wager of Battle, the Ordeal, and Torture
Third revised and enlarged editiou. In one handsome
volume, royal 12mo., <>rri52 piigos. Cloth, $2 50.
Lea's Studies in Churcii History — The Rise of tlieTemporal
Power — Benefit of Clergy— Kxcommuuicutiou. • In one
large royal r2ino. volume of 616 pages. Cloth, $2 75.
(hatnly Published.)
Lea's Historical Sketch of Sacerdotal Colihacy in the Chris-
tian Church. In one handsome octavo volume of 600
pages. Cloth, $3 75. (Lately Published.)
Detailed Catalogues fiHiiislicd on application. Illustrated Ciiliiloguos sent on receipt of 10 cents.
HENRY C. LEA, Philadelphia.
m^
■;?:v'o^<«ftf '
.,y}^^t*
Live Music Archive
Librivox Free Audio
Metropolitan Museum
Cleveland Museum of Art
Internet Arcade
Console Living Room
Books to Borrow
Open Library
TV News
Understanding 9/11