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QUAIN’S ANATOMY.

: QUAIN’S
ELEMENTS OF ANATOMY y

ANS dew NED -

EDITED BY Sah we WS)

WILLIAM SHARPEY, MD, LL.D, FRS. L & B,

EMERITUS PROFESSOR OF ANATOMY AND PHYSIOLOGY IN UNIVERSITY COLLEGE, LONDON

ALDEN THOMSON, MD, LLD, FRS. L. -& EH,

PROFESSOR OF ANATOMY IN THE UNIVERSITY OF GLASGOW
AND

EDWARD ALBERT SCHAFER

ASSISTANT PROFESSOR OF PHYSIOLOGY IN UNIVERSITY COLLEGE, LONDON

IN TWO VOLUMES.

ILLUSTRATED BY UPWARDS OF 950 ENGRAVINGS ON WOOD.

VOE EF

Cighth Evition, APR 06 igre

LIBRARIES.

NEW YORK
WILLIAM WOOD AND CO., PUBLISHERS
27 GREAT JONES STREET
18738.

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ADVERTISEMENT
TO THE EIGHTH EDITION.

——

THE first four Editions of ‘‘ Quain’s Elements of Anatomy”
were the work of the late Dr. Jones Quain; and it has been deemed
advisable still to retain the title by which the book has been so long
known, notwithstanding that in passing through the succeeding
three Editions, and that which now appears, it has undergone
alterations so extensive and fundamental that little of the original

text now remains.

Of these later Editions, the fifth was brought out under the
editorship of Professor Richard Quain and Dr. Sharpey; the sixth
was edited by Dr. Sharpey and Professor Ellis, and the seventh by
Dr. Sharpey and Dr. Allen Thomson, in association with Dr.
Cleland, Professor of Anatomy in Queen’s College, Galway, whose
extensive and exact knowledge of the existing state of Anatomical

Science was of much service throughout the work.

In the present Edition the distribution of the matter between
the two volumes has been in some respects altered; and it is be-
lieved that the use of the book by students will be facilitated by

the change.

The First Volume consists of the Special or Descriptive
Anatomy of the Bones, Joints, Muscles, Vessels, and Nerves. It

also includes the subject of Surgical Anatomy, which was formerly

vi ADVERTISEMENT.

treated of in a distinct chapter, originally written by Mr. Quain, but
this is now incorporated, in substance at least, with the description
of those Muscles and Bloodvessels to which it has special reference.
It will be further noticed that the description of the Bones and
Muscles has undergone considerable change, that in both of these
sections a short account of the Morphology has been introduced,
and that in that on the Muscles the varieties have been more fully
described than in the previous Editions. The whole of this volume
has been edited by Dr. Thomson, in association with Mr. David
N. Knox, M.B., Demonstrator of Anatomy in the University of
Glasgow, and assisted by Mr. H. Clarke in the description of
the Bloodvessels, and by Dr. Gowers in that of the Cranial Nerves.

Tn the Second Volume the section on General Anatomy and the
chapters on the Heart, the Respiratory, Vocal, Digestive, and
Urinary Organs, and the Organs of the Senses, have been revised
throughout, and in certain parts re-written by Dr. Sharpey, in
association with Mr. Schafer, by whom, it is right to state, the task
has in large measure been performed. The Section on General
Anatomy was completed and printed off in October, 1874. The
account of the Brain and Spinal Cord has been carefully revised
with especial regard to intimate structure, by Dr. Gowers, Assistant
Physician to University College Hospital. Lastly, Dr. Thomson,
who has revised the description of the Reproductive Organs, has
contributed a chapter on Embryology, with which the second volume
concludes. In this it has been his object to give, in such a form as
is suited to an elementary work on Human Anatomy, a short
general view of the Development of the Embryo, and of the Forma-
tion of the Membranes and the Placenta; and with this there is
now brought together into one place the special history of the
Development of the Several Organs of the Body which in the

previous Edition was distributed throughout the work.

While due reference has been made to the leading authorities

ADVERTISEMENT, vil

on the different subjects treated of, many points have been re-
investigated and new matter has been introduced from original

observation.

A considerable number of new figures have been introduced into
the present Edition, some having been substituted for former ones
now withdrawn, others added as new illustrations. They are partly
from original drawings, and partly electrotype copies of figures in
other published works, for their courtesy in allowing copies of which
the Editors have to thank the respective Authors and Publishers.

In the seventh Edition a large number of new figures were intro-
duced, of which the originals were drawn by Dr. Allen Thomson,
and by Mr. R. Tennant under his superintendence, and the engray-
ing was executed by Mr. Stephen Miller of Glasgow. To these
only a few have been added in the first volume of the present Edi-
tion. But in the General Anatomy and other parts of the Second
Volume of the present Edition a considerable number of new figures
have been added, the original drawings for which have been executed
chiefly by Mr. Schafer and Mr. Wesley, and the engravings by

Mr. Pearson.

The Table of Contents and the Index, with the accompanying
explanation of the derivation of terms, have been compiled by
Dr. Alexander Henry.

October, 1875,

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CONTENTS.

ELEMENTS OF ANATOMY.

INTRODUCTION 3 I
Objects of Anatomy . I
General and Descriptive Anatomy 5 : : : : ; I
Plan of Organisation: Vertebrate Type . wae : : exc 2
Divisions of Descriptive Anatomy : 4

DESCRIPTIVE OR SPECIAL ANATOMY.

PAGE PAGE
SECTION I.—OSTEOLOGY 7 Inferior Turbinated Bones. 53
The Skeleton if Inferior Maxillary Bone 53
I. Tas VERTEBRAL ConuMN 9 Hyoid Bone . 55
Vertebree 9 Tur SKULL AS A WHOLE 56
General Characters . 9 The Sutures : 56
Groups of Vertebree 10 External Surface of the
Cervical Vertebre . fe) Skull . 5S
Dorsal Vertebree 12 Interior of the Cranium. 62
Lumbar Vertebre . 13 Nasal Cavities and Com-
Sacral Vertebre . 15 muvicating Air-Sinuses 65
Coceygeal Vertebree 17 Ossification of the Bones of
The Vertebral Column as a the Head - 67
whole . 18 GENERAL MorpHoLocy oF
Ossification of the Vertebre 19 THE BONESOF THEHEAD 73
General and Serial Homo- Classified List of the Bones
logy of the Vertebrie 22 of the Head, and their
I]. THe THoRAX. Typical Ceupouent
The Sternum or Breast-Bone 25 IPantstiei 74.
The Ribs ‘ 27 Various Forms of Skull . Gt]
The Costal Cartilages 29 IY. Bones oF THE Upper Lims 81
The Thorax as a whole eZ Scapula. : SOE
Ossification of the Ribs and Clavicle 84.
Sternum. 30 Humerus 85
III. Tar Bones or roe Heap 31 Radius 87
Occipital Bone 31 Ulna 88
Parietal Bones . 34. Carpus p go
Frontal Bone. 35 Scaphoid Bone . oI
Temporal Bones . 37 Semilunar Bone 91
Sphenoid Bone 41 Cuneiform Bone. gI
’ Ethmoid Bone : » 45 Pisiform Bone 92
Superior Maxillary Bones . 46 Trapezium Bone 92
Palate Bones : 49 Trapezoid Bone 92
Vomer . 51 Os Magnum 92
Malar Bones 51 Unciform Bone 93
Nasal Bones . 52 Metacarpus é 93
Lachrymal Bones 52 Digital Phalanges . 94

x
Ossification of the Bones of
the Upper Limb .
VY. THe PeEtvis AND LOWER
LIMB. .
Innominate Bone
Tlium
Os Pubis
Ischium

The Pelvis .
Position of Pelvis
Differences according to
Sex , 5
Femur .
Patella
Tibia
Fibula
Tarsus . 4 a
Calcaneum or Os Calcis :
Astragalus .
Scaphoid Bone
Cuneiform Bones
Cuboid Bone .
Metatarsus
Phalanges .
The Bones of the Foot as a
Whole
Ossification of the Bones of
the Pelvis and Lower
Limb .
MorrnoLocy OF THE Bors
OF THE Limss
Relation to the
Skeleton .
Homological Comparison
of Upper and Lower
Limbs
Shoulder
Girdles
Bones of the Tambs
Hand and Foot
Table of the Homologous
Bones in the Thoracic
and Pelvic Limbs
Carpus and Tarsus
Seapula and Ilium .
Adaptation of the Skeleton
to the Erect Attitude .

Axial

and Pelvic

SECTION IJ.—ARTHROLOGY.
THE ARTICULATIONS IN
GENERAL :

Various Forms of Joints

Various kinds of Movement

ARTICULATIONS OF THE TRUNK

AND HEAD.

Articulations of the Verte-
bral Column :

Articulations of the Atlas,
Axis, and Occipital
Bone j °

Articulations of the Ribs

Temporo- Maxillar, y Articn-
lation

CONTENTS.

PAGE |

95

100
100
IOI
102
103
104
105

106
107
110
110
112

114

123

ARTICULATIONS OF THE UPPER
LIMB .
The Scapulo- -Clavicular Arch

Sterno-Clavicular Articu-
lation .

Scapulo- -Olavicular
culation :

Ligaments of the Scapula

Articulations of the Fore-
Armand Elbow . .

Superior Radio-Ulnar Ar-
ticulation

Inferior Radio- Ulnar Ar-
ticulation

The Elbow-Joint :
The Wrist-Joint and Arti-
culations of the Hand .

Radio-Carpal Articula-
tOTget

Carpal Articulations .

Carpo-Metacarpal and Jn-
termetacarpal Articula-
tions é

Metacarpo- -Phalangeal ‘and
Interphalangeal Articu-
lations

ARTICULATIONS OF THE PE LV IS
Articulation of the Pelvis
with the last Lumbar
Vertebra
Articulation of the Sacrum
and Coccyx, and of the
Pieces of the Coccyx
Sacro-Iliac Articulation
ARTICULATIONS OF
Lower LimMB
The Hip-Joint
The Knee-Joint .
Tibio-Fibular Articulations
The Ankle-Joint :
Articulations of the Foot

Articulations of the Cal-
caneum, Astragalus, and
Scaphoid Bones

Caleaneo-Cuboid Articu-
lation .

Articulations of the Sca-
phoid, Cuboid, and Cu-
neiform Bones

Articulation of the Tarsus
with the Metatarsus

Metatarso-Phalangeal and
Interphalangeal Arti-
culations - " .

Arti-

THE

SECTION III.—MYOLOGY.
THE MUSCLES IN GENERAL .
FAscra . :

Muscies AND FASCLa OF THE
Uprer Lime .
Between the Trunk and Up-
per Limb posteriorly
Between the Trunk and Up-
per Limb anteriorly

PAGE

146
146

146

146
148

177
179
181
183
185
187
187
193

CONTENTS.

PAGE
Action of the Muscles be-
tween the Trunk and

Upper Limb 198
Muscles and Fascize of the
Shoulder : 199
Muscles and nee of the
Upper Ar 205
Muscles and Wages of the
Fore-Arm : 208
Pronator and Flexor Mus-
cles)" 209
Supinator and Extensor
Muscles . 215
Muscles of the Hand . 221
Muscles of the Thumb . 221
Muscles of the Little
Finger 222
Interosseous Muscles . 222
Action of the Muscles of the
Fore-Arm and Hand 224
MuscLrs AND FASCIZ OF THE
Lower Limp. 226
Fascie of the Hip and Thigh 226
Muscles of the Hip ‘ 228
Posterior Femoral or Ham-
string Muscles 232
Anterior Muscles of the
Thigh, _. 234
Internal Femoral or Ad-
ductor Muscles . 240
Action of the Muscles of the
Hip and Thigh - 243
Muscles and Fascie of the ~
Leg and Foot 243
Anterior Region 243
External Region 248
Posterior Region 248
The Plantar Fasci and
Muscles . 255
First layer of Muscles. 2 56
Second layer 257
Third layer 257
Fourth layer : 258
Action of the Muscles of the
Leg and Foot 5. BS)
MorPHouocy oF THE LiIMp-
Muvsciks 260
Table of Muscular Homo-
logies in the Upper and
Lower Limb 262
Muscies AND FASCI# OF THE
HEAD AND NECK 264
Epicranial Region 264
Auricular Muscles - . 265
Muscles of the ee and
Eyebrows 265
Muscles of the Nose . 269
Muscles of the Lips and
Mouth . ? 270
Muscles of the Orbit . 275
Muscles of Mastication . 278
Muscles between the Lower
Jaw and the Hyoid
Bone . : P 5 het

Muscles of the Phar and
Soft Palate ia
Subcutaneous Muscle of the
Neck .
Muscles and Fascice of the
Neck anteriorly
Deep Lateral and Preverte-
bral Muscles of the
Neck .
MUscLzEs AND FAscim OF THE
TRUNK .
Dorsal Muscles and Fascia
Muscles of the Thorax
Intercostal Muscles
Diaphragm t :
Movements of Respiration -
Muscles and Fascie of the
Abdomen
Lining Fascia of the ‘Abdo-
men 3
Muscles and Fascie of ‘the
Perineum and Pelvis .
Fasciz of the Perinzeum .
Fascie of the Pelvis
Muscles : A. in the Male
B. in the Female
MorpPHouocy oF THE FAscrm
AND MUSCLES OF THE
TRUNK AND HEAD
StureicaAL ANATOMY OF HER-
NIE
Inguinal Hernia
Femoral Hernia

SECTION IvV.—
Buioonp- VESSELS ;
AND VEINS
PULMONARY ARTERIES AND
VEINS ‘
Pulmonary Artery
Pulmonary Veins .
Tuer Sysremic ARTERIES
AORTA . ‘
Arch of the Aorta 2 5
Varieties of the Aorta and
Pulmonary Arteries
BRANCHES OF THE ARCH OF
THE AORTA
Coronary Arteries .
Innominate Artery
Common Carotid Arteries
Surgical Anatomy of the
Common Carotid Artery
External Carotid Artery
Branches. -
Internal Carotid Artery
Branches .
Distribution of the Arteries
in the Cerebrum
Subclavian Arteries
Branches .
Surgical Anatomy of the
Subclavian Arteries

ANGEIOLOGY.
ARTERIES

CONTENTS,

PAGE
Axillary Artery . 394
Branches 395
Brachial Artery . 399
Branches 401
Surgical Anatomy of the
Brachial Artery . 405
Ulnar Artery 407
Branches ; 407
Superficial Palmar Arch 411
Radial Artery 413
Branches : 415
Deep Palmar Arch . 418
DeEsceNDING THORACIC AORTA 419
Branches to the Viscera 420
Parietal Branches to the
Thorax 420
ABDOMINAL AORTA . 422
A.—Visceral Branches of
the Abdominal Aorta . 424
B.—Parietal Branches of
the Abdominal Aorta . 435
Minute Anastomoses of the
Visceral and Parietal
Branches of the Abdo-
minal Aorta 436
Middle Sacral Artery 437
Common Iliac Artery . . 437
Surgical Anatomy of the
Common Iliac Artery . 439
Internal Iliac Artery . 439
Hypogastric Artery 440
Branches of the Internal
Iliac Artery 440
External Iliac Artery 450
Branches 451
Surgical Anatomy of the
Iliac Arteries 453
Femoral Artery . 453
Branches 450
Surgical Anatomy of the
Femoral Artery . 461
Popliteal Artery 461
Branches ; 461
Posterior Tibial Artery . 463
Branches 464
Plantar Arteries : 4605
Anterior Tibial Artery 468
Dorsal Artery of the Foot . 469
Tue SystEmic VEINS . 472
Superior VENA CAVA 472
Innominate or Brachio-
Cephalic Veins 473
Veins of the Head and
Neck . 475
Venous Cir culation with-
in the Cranium 480
Cerebral Veins 480
Cranial Sinuses . 481
Ophthalmic Vein . 484
Veins of the Diploé 485
Veins of the Upper Limb 485
Superficial Veins. 486
Deep Veins 487
Axillary Vein 488

Subclavian Vein
Azygos Veins .
Veins of the Spine
INFERIOR VENA CAVA.
Veins of the Pelvis and
Lower Limb .
Superficial Veins of the
Lower Limb i
Deep Veins of the Lower
Limb * . :
External Iliac Vein
Internal Iliac Vein.
Common Iliac Vein
PorTAL SysTEM OF VEINS .
VEINS OF THE HEART.
THE ABSORBENT VESSELS.
Thoracic Duct .
Right Lymphatic Duct.
an hee sc of the Lower
Li

Lymphatics of the Abdomen
and Pelvis. ¢

Lymphatics of the Thorax .

Lymphatics of the Upper
Limb .

se rasa of the Head and
Neck

SECTION V.—NEUROLOGY

THE CEREBRO-SPINAL NERVES

I. CRANIAL NERVES

Connection with Ence-
phalon . :

Mode of Exit from the
Cranium

General Distribution .

Olfactory Nerve .

Optic Nerve . ;

Third Pair of Nerves .
Position of Nerves at the

Cavernous Sinus and as
they enter the Orbit

Fourth Pair of Nerves

Fifth Fair of Nerves
Ophthalmic Division
Ophthalinic Ganglion .
Superior Maxillary Nerve
Spheno-Palatine Ganglion
Inferior Maxillary Nerve
Otic Ganglion :
Submaxillary Ganglion

Sixth Pair of Nerves .

Seventh Pair of Nerves .
Facial Nerve .

Auditory Nerve .

Eighth Pair of Nerves
Glosso-Pharyngeal Nerve
Pneumo-Gastric Nerve
Spinal Accessory Nerve .

Ninth Pair of Nerves

II. SprnaL NERVES.

The Roots of the uae
Nerves

Posterior Primary Divisions
of the Spinal Nerves
The Suboceipital Nerve .
Cervical Nerves . :

Dorsal Nerves
Lumbar Nerves .
Sacral Nerves.
Coccygeal Nerves

Anterior Primary Divisions

of the Spinal Nerves
Cervical Nerves .
Suboccipital Nerve
Second Cervical Nerve
The Cervical Plexus .
Superficial Ascending
Branches
Superficial Descending
Branches. ie
Deep Branches; In-
ternal Series
Deep Branches ; Exter-
nal Series
The Brachial Plexus :
Branches above the Cla-
vicle
Branches below the Cla-
vicle
Anterior Thoracic
Nerves 2
Subscapular Nerves .
Circumflex Nerve
Internal Cutaneous
Nerve .
Musculo - Cutanéous
Nerve .
Ulnar Nerve
Median Nerve . ;
Musculo-Spiral Nerve
Radial Nerve
Posterior Interosseous
Nerve .
Dorsal Nerves
First Dorsal Nerve
Upper or Pectoral In-
tercostal Nerves .
Lower or Abdominal
Intercostal Nerves .
Last Dorsal Nerve
Lumbar Nerves .
The Lumbar Plexus
Ilio- Hypogastric and
Ilio-Inguinal Nerves
Genito-Crural Nerve
External Cutaneous
Nerve
Obturator Nerve
Anterior Crural Nerve
Fifth Lumbar Nerve
Sacral and pocrecst
Nerves ;

CONTENTS. xili

PAGE

PAGE

Fourth Sacral Nerve . 608

Fifth Sacral Nerve. . 608

The Coccygeal Nerve . 608

The Sacral Plexus . . 609
Small Muscular

Branches . ; nome

The Pudic Nerve . . 610
Small Sciatic Nerve . 613

Great Sciatic Nerve . 615
Internal Popliteal
Nerve . 616

Posterior Tibial Nerve 61 7
Internal Plantar

Nerve. 617
External Plantar
Nerve . 619
External Popliteal
INGE 6 Tee OG
Anterior Tibial
Nerve . 621

SYNOPSIS OF THE CUTANEOUS
DISTRIBUTION OF THE
CEREBRO-SPINAL NERVES 622

SYNOPSIS OF THE MUSCULAR
DISTRIBUTION OF THE,
CEREBRO-SPINAL NERVES 624

III. SympaTHEeTic NERVES. . 626
Cervical Part of the Gang-
liated Cord A 628

Upper Cervical Gan clion 628
Ascending Branch
and Cervical Plex-

uses a O26
Pharyn geal Nerves
and Plexus . . 630

Upper Cardiac Nerve 630
Branches to Blood-

vessels. 632
Middle Cervical Gang-
lion 632
Lower Cervical Gang-
lion . 633
Thoracic Part of the Gang-
liated Cord. 633

Branches of the Ganglia 633
Lumbar Part of the Gang-

liated Cord . : 636
Sacral Part of the Gang:
liated Cord. 636
Coccygeal Gland . . 637
The Great Plexuses of the
Sympathetic . 630
Cardiac Plexus : 638
Solar or Bpigastrc
Plexus. 639
Hypogastric Plexus. 641
Pelvic Plexus. - 641

INDEX. ; : - 1645

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CORRIGENDA AND ADDENDA.

. Page 26, line 6 from bottom, for ‘‘xyphisternum,” read ‘‘ xiphisternum.”
. Page 69, line 6 from bottom, for ‘‘ Opistotic,” read ‘‘ Opisthotic.”
«Page 81. In third paragraph under Scapula, line 3, for ‘‘regular,” cad ‘‘ oblique.”
-Page 87. In paragraph under Varieties, line 7, for ‘‘ completing,” read ‘‘ enclosing.”
- Page 94. At the end of paragraph in small type, after ‘‘middle row,” add ‘but
this view is not generally adopted by anatomists.”’
+ Page 99, line 13 from the bottom, for ‘‘ epiphysis,” read <‘ epiphyses.”’
« Page 111, line 12, insert the word ‘‘crucial’’ before ‘‘ spine.”
* Page 129. In title of Table Il, instead of ‘‘ after Gegenbaur,” read ‘‘ modified from
that of Gegenbaur.”’
+ Page 158, line 17, omit ‘‘A. T.”’
«Page 172, line 26, for ‘‘ relaxed,” read ‘‘ expanded.”
+ Page 175, line 17, for ‘‘ lateral ligaments,” read ‘‘ internal lateral ligament.”
-Page 176. In Figure 158, a posterior ligament is erroneously represented.
+ Page 181, line 15 from the bottom, for ‘‘ Interdigital,” read ‘‘ Interphalangeal.”
~ Page 186, line 16 from the bottom, for ‘‘ rectinacula,” read ‘‘ retinacula.”’
* Page 220, line 4 from the bottom, insert a comma after ‘‘anconeus,” and one after
*supinator longus.”
« Page 276, line 5 from the bottom, for ‘‘ orbitis,” read ‘‘ orbitz.”
+ Page 329, near middle, for ‘‘levator coccygei,”’ read ‘‘ levator coccygis.”’
Page 343, at the top, for ‘‘ Ancrotoay,” read ‘* ANGEIOLOGyY.”
* Page 361, near the bottom, for ‘‘ Carrorp,’ read ‘* Carotrp.”’
Page 375. In small print paragraph under ‘‘ Branches,” line 1, for ‘‘ lachmyral,”

read “ lachrymal.” Lo ae
« Vind

The present edition (1878) is a reprint,
without alteration, of the eighth edition, published in 1875.

ELEMENTS OF ANATOMY.

INTRODUCTION.

Object of Anatomy.—The object of Anatomy, in its most extended
sense, is to ascertain and make known the Structure of Organised Bodies.
But the science is divided into departments according to its subjects ;
such as, Human Anatomy, in which, as in the present work, the struc-
ture of man forms the principal subject ; Comparative Anatomy, com-
prehending, as a whole or in various subdivisions, the study of the
structure of different animals ; and Vegetable Anatomy, comprehending
the investigation of the structure of plants.

Organs and Textures.—On examining the structure of an organised
body, we find that it is made up of members or organs, through means
of which its functions are executed, such as the root, stem and leaves of
a plant, and the heart, brain, stomach, and limbs of an animal ; and
farther, that these organs are themselves made up of certain constituent
materials named tissues or textures, as the cellular, woody, and vascular
tissues of the vegetable, or the osseous, muscular, connective, vascular,
nervous, and other textures, which form the animal organs.

Most of the textures occur in more than one organ, and some of them
indeed, as the connective and vascular, in nearly all, so that a multitude
of organs, and these greatly diversified, are constructed out of a small
number of constituent tissues, just as many different words are formed
by the varied combination of a few letters ; and parts of the body,
differing widely in form, construction, and uses, may agree in the
nature of their component materials. Again, as the same texture
possesses the same essential characters in whatever organ or region it is
found, it is obvious that the structure and properties of each tissue
may be made the subject of investigation apart from the organs
into whose formation it enters.

General and Descriptive Anatomy.—The foregoing considerations
naturally point out to the anatomist a twofold line of study, and have
led to the subdivision of anatomy into two branches, the one of which
treats of the nature and general properties of the component textures of
the body ; the other treats of its several organs, members, and regions,
describing the outward form and internal structure of the parts, their
relative situation and mutual connection, and the successive conditions
which they present in the progress of their formation or development.
The former is usually named “ General” Anatomy, or “ Histology ” ;*
the latter ‘‘ Descriptive” or “ Special” Anatomy.

* From iotbs, a web.
VOL, I. ‘ B

INTRODUCTION.

bo

Descriptive Anatomy may be treated of in two methods ; viz., the
Systematic and the Topographical.

In the first or Systematic Anatomy, the several organs and parts of
the body are considered in a systematic order, according to their
structure, their connection with each other, and their relation to the
purposes of life ; while in the second, or Topographical Anatomy, the
parts are described in the order of their position or association in the
same region of the body. The first method is best adapted for the
elementary and complete study of the structure of organs, the second is
more immediately useful in the study of particular regions in their
relation to medicine and surgery. The object of the present work
being mainly to serve as a guide for systematic study, the topographical
details will be included under and combined with the general descrip-
tion of organs.

The anatomical description of any organ embraces the consideration
of its form, size, position, connection and texture ; the whole of these
comprising the structure of the organ. The adult or fully formed
condition of the body is commonly assumed as the subject of this
description ; but it is obvious that a consideration of the structure of
the body and its organs in different stages of life is required to render
the knowledge of their anatomy complete. The study of the origin and
formation of organs in the embryo, known under the names of
Embryological Anatomy or Fetal Development, to which a separate
chapter will be devoted in this work, is of peculiar importance in indi-
cating the general relations of organic structure.

The study of anatomy may be viewed in two different aspects ;
viz., the Physiological and the Morphological. In connection with the
first, anatomy supplies the materials relating to structure from which an
explanation is sought of the uses or functions of organs by the
physiologist ; and for this purpose the study of Textural Anatomy is of
particular service. In connection with the study of Morphology,
Descriptive Anatomy investigates and combines the facts relating
to structure and relations of organs, from which may be deduced
general principles as to the construction of the human body or that of
animals. In the determination of these general principles, or laws of
Morphology, it is necessary to combine the knowledge of the anatomy
of animals with that of man, and both of these with the study of
development.

PLAN OF ORGANISATION.

Vertebrate Type.—The general plan of construction of the
human body agrees closely with that which prevails in a certain
number of animals, viz., mammals, birds, reptiles, amphibia, and
fishes, and is known as the vertebrate type of sorganisation. The
main feature of that type, and that from which its name is
derived, belongs to the internal skeleton, and consists in the exis-
tence of a number of bones (or cartilaginous substitutes) termed
vertebree, which extend in a loneitudinal series through the whole
trunk of the body, and which by their more solid part, termed
centrum or body, are so disposed as to form a pillar or axis, round
which the rest of the parts are arranged with a certain conformity of
structure. At one extremity of this pillar is situated the head, present-

PLAN OF ORGANISATION. 3

ing in almost’ all the animals formed upon this type the character of
increased development of its constituent parts: and at the other the
tail in which an opposite character or that of diminution prevails :
while on the sides of the main part or érunk, there project in relation
with some of the vertebral elements two pairs of symmetrical limbs
in two situations, which are determinate and similar in different
animals.

The head and trunk contain the organs or viscera most important to
life, such as the alimentary canal and the great central organs of the
sanguiferous and nervous systems, while the limbs, from which such
principal organs are absent, are less constant and differ more in
the degree of their development among the various animals formed upon
the vertebrate type. The whole body may thus be regarded as being
formed of an azial portion consisting of the head and trunk, and of
appendicular portions comprising the limbs. In man and the higher
animals especially, the trunk presents a division into the neck, chest,
abdomen, and pelvis.

The vertebrate form of skeleton is invariably accompanied by a
determinate and comformable disposition of the other most important
organs of the body—as first, by the existence on the dorsal aspect
of the vertebral axis of an elongated cavity or canal which contains
the brain and spinal cord, or central organs of the nervous system ; and
second, by the existence on the ventral aspect of the vertebral axis of a
larger cavity, the visceral cavity, in which are contained the principal
viscera connected with nutrition, such as the alimentary canal, the
heart and lungs, the great blood-vessels, and the urinary and genital
organs.

The general disposition of the parts of the body and of the more
important viscera in their relation to the vertebral axis are shown in
the accompanying figures of the external form and longitudinal and
transverse sections of the human embryo at an early period of its
existence, when its structure resembles more closely that of the lower
animals.

Fig. 1.—Lareran Virw oF Fig. 1.
THE Human EmMpryo ABOUT
SevEN WEEKS OLD; THE
VERTEBRAL AXIS PLACED

HORIZONTALLY. MAGNIFIED ay yt. $
aS SS NN “hy,
Azout7 Diameters. (A.T.) S Se Ca
Mie. Wyn? 2
8, 8, indications of the ver- : | Ny ox
tebral divisions along the line \ ie i
of the back ; 7, w, anterior \ y

or upper limb ; ¢, f, posterior
or lower limb ; wu, umbilical !
opening. In the cranial part )
the divisions of the brain are \\
indicated, together with the
eye, and au, the auditory
vesicle ; near 5, the ventral
plates of the head with the rudiments of the upper and lower jaws. These plates and
the apertures between are represented in a state belonging to a somewhat earlier stage
than the rest of the body.

2

Segmented Character.—The vertebrate type of organisation possesses, there-

fore, in the repetition of similar structural elements in a longitudinal sre
B

4 INTRODUCTION.

a segmented character, especially in the axial portion of the body, and this
segmentation affects more or less, not merely the skeletal parts of its structure,
but also, to some extent, its other component organs,

Fig. 2.—SEMIDIAGRAMMATIC
View oF A LONGITUDINAL
SEcTION OF THE Empryo
REPRESENTED IN Ficure 1;
SHOWING THE RELATIONS
OF THE PRINCIPAL SYSTEMS
AND ORGANS TO EACH
OTHER IN THE HoRIzONTAL
PosttIoN OF THE VERTE-
BRAL Axis. (A. T.)

1, 2; 73,7) 45 5) primary,
divisions of the brain in the
cranial part of the neural
canal ; n, m, spinal cord in
the vertebral part of the
same; s, one of the spinous
processes of the vertebrae
(4th dorsal) ; ch, chorda dorsalis running through the axis of the vertebral centra or
bodies; ch’, the same extending into the base of the cranium ; a, dorsal aorta; p,
pharyngeal cavity ; 2, 7, alimentary canal ; hf, ventricular part of the heart, from which
the arterial bulb is seen joining the aorta by arches; 6, branchial plates ; 7, liver ; w,
Wolffian body ; v, urinary vesicle or allantois, joining the intestine in the cloaca; u, w’,
umbilicus.

Fig. 38.—TRANSvERSE SEcTION (DIAGRAMMATIC) OF THE TRUNK OF THE Empryo
THROUGH THE ANTERIOR Limps, (A. T.)

m, spinal cord ; n, neural or dorsal arch, including bone, muscle, skin, roots of the
nerves, &c. ; ch, chorda dorsalis, surrounded by the vertebral body or centrum ; 7%,
ventral or visceral arch, or wall of the body ; p, p, pleuro-peritoneal cavity ; 7, alimen-
tary canal ; h, heart; /, 7, the rudimentary limbs.

Fig. 4.—First Dorsan VERTEBRA WITH THE First Rip AND UPPER PART OF THE
STERNUM, SEEN FROM ABOVE. 1

3

C, body or centrum ; iV, neural arch or vertebral ring ; V, cavity of the chest, visceral
cavity.

It is true that a segmented plan of construction is not restricted to vertebrate
animals, but exists in several other classes of the animal kingdom, as is most
conspicuously seen in the class Articulata, such as insects and crustacea. In
these animals, however, there are many important deviations from the verte-

VERTEBRATE TYPE. 5

brate type of organisation, although there is an agreement in the repetition of
parts of like structure in a longitudinal series; and it is unnecessary here to
trace the correspondence between their structure and that of man.

In the human body, as in that of all vertebrate animals, the character of
segmentation is most obvious in the osseous and nervous systems, so that the
form and structure of the other systems seem to be in some measure moulded
upon those of the skeleton and cerebro-spinal axis.

The trunk of the body more especially is formed of a series of parts or
segments of similar structure sufficiently distinct in some of the systems, but
more or less blended together in others. Such ideal segments of the body may be
named vertebral segments, or somatomes (Goodsir). In the limbs, although in the
earliest stages of their formation some segmental connection may be traced
between them and the trunk, the repetition of vertebral elements is, in their
more advanced state of growth greatly obscured by the modifications of form
and structure they have undergone.

Vertebrate Homology.—A correspondence in the structure and connection of
parts or organs constitutes what is now called anatomical homology, and the
same term is frequently employed to designate anatomical correspondence of
parts serially repeated in the same animal: but for this last or serial homo-
logy the modified term of homotypy, suggested by Owen, may with advantage
be substituted. 'Thus, the arm-bone or humerus of man is homologous with the
upper bone of the foreleg of a quadruped or of the wing of a bird, while it is
properly homotypic with the thigh-bone of man himself or any other vertebrate
animal. It has further been found convenient to express by the word analogy
that kind of resemblance among the organs of animals which, though indicating
similarity of function, and even in some respects of structure, is not rendered
complete by anatomical relation and connection. This general resemblance may
be very great ; but it is of a different kind from that absolute identity which is
implied by the term anatomical homology, which is intended to convey the idea
of entire correspondence in fundamental structure, position, and connection of
any organ, or set of organs, in relation to a general plan or type of construction
of the organism, and which might be almost looked upon as synonymous with
anatomical identity—a correspondence, too, which is conceived to be traceable
through all the modifications, however great, which the form and structure of
the organs may have undergone in the course of their development. Thus,
the heart of a fish or amphibian, though very different in external form and
internal arrangement, is strictly homologous with that of a mammal or of man ;
or, in other words, it is anatomically the corresponding organ. But the heart of
the crustacean, though muscular in its structure, and fitted to propel the blood
through the system, and thus analogous to the heart of a vertebrate animal, is
not regarded as strictly homologous with it, because it differs in its anatomical
relation to the rest of the organism, and cannot be referred to the same place in
a general plan of structure.

Symmetry of Form.—A remarkable regularity of form pervades the organisa-
tion of certain parts of the body, especially the whole of the limbs, the head
and neck, and the framework, at least, and external walls of the trunk of the
body. Thus, if we conceive the body to be divided by a plane which passes from
its dorsal to its ventral aspect (mesial plane), the two halves, in so far as regards
the parts previously mentioned, correspond almost exactly with each other, ex-
cepting by their lateral transposition,—and the human body thus presents in a
marked manner the character of lateral symmetry. There is, however, a depar-
ture from this symmetrical form in the developed condition of certain of the
internal organs, such as the alimentary canal from the stomach downwards, the
heart and first part of the great bloodvessels, the liver, spleen, and some other
viscera, which are therefore styled the non-symmetrical parts or viscera.

But, while the parts on each side of the mesial plane are thus so far symmetrical,
the same correspondence does not hold between parts situated in the dorsal and
ventral regions, nor even between those placed in the cephalic and caudal extre-
mities of the body. In the first, with the exception of the division of the
ventrally-placed sternum into segments which often correspond to a certain
number of the dorsal vertebra, no such dorso-ventral symmetry exists : and in the

6 INTRODUCTION.

longitudinal axis of the trunk, as previously stated, the similarity between the
cephalic and caudal parts is of a different and only a remote kind ; that, viz., which
is involved in the repetition in series of vertebral elements, which, though funda-
mentally similar, yet differ greatly in the form and development of their parts.

Descriptive Terms.—In the description of parts so numerous, so various in
form, and so complex in their connections as those composing the human body,
there is difficulty in finding terms which shall indicate with sufficient precision
their actual position and their relation to the rest of the organism. This diffi-
culty is farther increased by the exceptional erect attitude in which the trunk of
the human body is placed as compared with the horizontal position in animals,
Hence, a number of terms have long been in use in human anatomy which are
understood in a technical or restricted sense. The mesial plane, for example,
already referred to, is that by which the body might be divided into right and
left lateral halves, and the middle or median line is that in which the mesial plane
meets the surface of the body. The words internal and external are used to
denote relative nearness to and distance from the mesial plane towards either
side, and might therefore be replaced by mesial and lateral. The words anterior
and posterior, superior and inferior, and several others indicating position, are
employed in human anatomy strictly with reference to the erect posture of the
body. But now that the more extended study of comparative anatomy and
embryonic development is largely applied to the elucidation of the human struc-
ture, it is very desirable that descriptive terms should be sought which may
without ambiguity indicate position and relation in the organism at once in man
and animals.

Such terms as dorsal and ventral, neural and visceral, cephalic and caudal,
central and peripheral, proximal and distal, axial and appendicular, preavial and
postaxial, are of this kind, and ought, whenever this may be done consistently
with sufficient clearness of description, to take the place of those which are only
applicable to the peculiar attitude of the human body, so as to bring the
language of human and comparative anatomy as much as possible into confor-
mity. In many instances, also, precision may be obtained by reference to certain
fixed relations of parts, such as the vertebral and sternal aspects, the radial or
ulnar, and the tibial or fibular borders, the jlevor or extensor surfaces of the
limbs, and similarly in other parts of the body.

DIVISIONS OF DESCRIPTIVE ANATOMY.

The systems and organs of the body to be described in this work
may conveniently be brought under the following divisions, viz. :—
1. Osteology, the Bones.
2. Arthrology, the Joints.
3. Myology, the Voluntary Muscles, with the Fascie and Apo-
neuroses.
4, Angeiology, the Distribution of the Blood-vessels and Lym-
phatics.
5. Neurology, the Distribution of the Nerves.
6. Splanchnology, the Viscera, including—
a. The Brain and Spinal Cord.
b. The Organs of the Senses.
c. The Heart.
d. The Lungs and Organs of Respiration.
e. The Organs of Digestion with the Accessory Glands.
f. The Urinary Organs.
g. The Organs of Reproduction.

The integuments will be described in the part on General Anatomy.

DESCRIPTIVE OR SPECIAL ANATOMY.

OSTEOLOGY.
—_4——_

THE SKELETON,

THE Skeleton or solid framework of the body is mainly formed of
the benes, but is completed in some parts by the addition of cartilages.
The bones are bound together by means of ligaments, and are so dis-
posed as to support the softer parts, protect delicate organs, and give at-
tachment to the muscles by which the different movements are executed.

In the lower animals the term skeleton has a wider signification than
in man, comprehending two sets of parts, viz., 1st, those of the endo-
skeleton, or the deeper osseous and cartilaginous framework which
corresponds to the human skeleton ; and 2nd, those of the exo-skeleton,
or dermal-skeleton, comprising the integument and various hardened
structures connected with it. All vertebrate animals possess an endo-
skeleton ; but in some of them the exo-skeleton attains greater pro-
portions than in others, and is combined by means of hardened paris
more fully with portions of the endo-skeleton. In almost all inverte-
brate animals the dermal or exo-skeleton alone exists.

In man, as in the higher vertebrates, the greater part of the endo-
skeleton is formed of bone, a calcified animal tissue, which, when freed
by putrefactive maceration from its fat and various soft adherent parts,
and subsequently dried, is capable of remaining unchanged for a very
long period of time. It is customary and convenient thus to study the
bones chiefly in the macerated and dried state, that is, deprived of their
accessory soft parts.

Certain accessory soft parts are connected with the bones: these con-
sist chiefly of the external fibrous and vascular covering termed periosteum,
and of the medulla, marrow or fat, which fills their larger internal cavi-
ties. The bones are permeated by blood-vessels, which supply materials
for their nourishment, and they are provided also with absorbent
vessels and with nerves in small quantity.

The bony substance or osseous tissue consists of an organised
animal basis which is essentially fibrous in its structure, and is inti-
mately combined with a large proportion of earthy and saline ingre-
dients. ‘The former gives tenacity, the latter hardness and rigidity to
the osseous substance. The earthy and saline matter may be obtained
separate by burning or calcination of bones in an open fire, and when
this is done with sufficient care, these may be preserved in the form of
the original bone. It constitutes about two-thirds of the weight of the
dried substance of bone, and consists mainly of a tribasic phosphate of
lime, or bone earth, together with about a fifth of carbonate of lime
and smaller quantities of fluoride of calcium, chloride of sedium, and
magnesian salts.‘

The earthy ingredients and salts of bone may be removed by soiu-
tion in hydrochloric acid, and there is thus obtained separately the

8 OSTEOLOGY.

animal constituent or organised basis of the bone-tissue, which retains
not only the general form, but also the minute structure of the original
bone. This is a tough, flexible, and mainly fibrous substance, which is
capable of being in great part resolved into gelatin by boiling.

The ends of the bones, when jointed moveably with others, are covered
by a thin layer of dense permanent cartilage, called articular cartilage ;
and the adjacent bones are united together by fibrous ligaments which
may be considered as continuous with the periosteum covering the rest
of the bones. In some instances distinct bones are directly united by
means of ligament or cartilage without any joint-cavity intervening.
Thus the osseous system as a whole may be considered to be enveloped
by a fibrous covering.

The bones are originally formed by a process termed ossification from
soft substance. This process commences in the greater number of bones
in cartilage ; in some it begins in fibrous tissue or membrane; and in all
instances the further growth of the bone substance takes place largely
in the latter way. ‘The deposit of bone begins generally at one spot,
which is therefore called the original point or primary centre of ossifica-
tion ; but there are sometimes several of these from the first. In most
bones, after considerable advance in growth by extension from the
original centre, ossification occurs at comparatively later periods in one
or more separate points, forming secondary or tertiary centres ; and the
portions of bones so formed, and remaining united to the main part for
a time by intervening cartilage, are termed epiphyses. In many instances
entire consolidation of the bone by the osseous union of the epiphyses
does not take place till the full size has been attained, and this may be
as late as the twenty-third or even the twenty-fifth year of life.

In their outward form the bones present much diversity, but have
been reduced by anatomists to the following classes:—1. Long or
cylindrical, such as the chief bones of the limbs. These consist of a
body or shaft, cylindrical or prismatic in shape, and two extremities
which are usually thicker than the shaft, and have smooth cartila-
ginous surfaces for articulation with neighbouring bones. The shaft is
generally hollow and filled with marrow, by which sufficient size and
strength are attained without undue increase of weight. 2. Tabular
or flat bones, like the scapula, ilium, and the bones forming the roof
and sides of the skull. 38. Short bones, which are more or less rounded
or angular, as in the carpus and tarsus. 4. Irregular or mixed bones,
mostly situated symmetrically across the median plane of the body, and
often of a complex figure, such as the vertebre.

In these differently shaped bones the osseous substance occurs in two forms,
viz., the compact and the spongy. There is, however, no essential difference in
structure or properties between these beyond that of thickness or thinness of the
component material.

The surfaces of bones present various eminences, depressions, and other marks,
to designate which the following terms are in common use. Any marked bony
prominence is called a process or apophysis, the main part of the bone being
sometimes named diaphysis ; while processes originally ossified from a distinct
centre are during their separate condition named epiphyses. A slender, sharp, or
pointed eminence is named a spine, or spinous process ; a blunt one a tubercle ; a
broad and rough one a tuberosity. The terms crest, line, and ridge are usually
applied to a prominent border, or to an elevation running some way along the
surface of a bone. <A Acad (caput, capitulum, or capitellum) is a rounded process
supported on a narrower part named the neck (cervix). The term condyle, some-

THE VERTEBRAL COLUMN. 9

what variously applied by anatomists, is most frequently employed to denote an
eminence bearing a flattened articular surface.

The cavities and depressions of bones are very various. An aperture or perfo-
ration, when short, is named a foramen ; when continued some way as a passage
it is termed a canal or meatus. A narrow slit is named a fissure, an open excayva-
tion or hollow in one or in several bones together is termed a fossa. This term is
» also sometimes applied to the socket of a joint, as in the glenoid or shallower,
~ and the cotyloid or deeper form of joint cavity. Sinus and antrwn are names
applied to considerable cavities in the interior of certain bones. Besides these,
various other terms are employed which do not require explanation, such as notch,
(incisura) groove, furron, (sulcus), &c.

The number of bones in the skeleton varies at different periods of
life, some which are originally distinct becoming united together as the
process of ossification advances. The following is a statement of the
number usually reckoned as distinct in middle life :—

Single bones. Pairs, Total.

The vertebral column . . 26 oo 26
The ‘skull? : A 2 eo 8 22
The hyoid bone . A ie | whe 1
The ribs and sternum . ea | ie 25
The upper limbs : slates 52 64
The lower limbs . : : 31 62

34 83 200

Besides the bones included in the above enumeration, there exist like-
wise the small auditory ossicles, and various bones formed in tendons and
called sesamozd, such as the patella, and those of the thumb and great
toe, usually amounting to 8 pairs or 16 in all.

I—THE VERTEBRAL COLUMN.

The vertebral column is composed of a series of bones called verte-
bre, which are united together, for the most part, by joints and elastic
substance in such a manner that, although the amount of motion
allowed between each pair is slight, the aggregate is sufficient to give
the column very considerable flexibility. The vertebree are originally
thirty-three in number. Of these, the twenty-four upper remain
separate in the adult, retaining their mobility, and are hence called
moveable vertebre. They are succeeded by five others, which rapidly
diminish in size from above downwards, and which are united into one
mass called the sacrum ; beyond the sacrum are four dwindled terminal
members of the series, which as age advances, likewise become more or
less united, and form the coccyz. These sacral and coccygeal vertebree
have thus been called the /ized or wnited vertebree.

General characters of the Vertebre.—The general characters are
best seen in the vertebre placed near the middle of the column, of
which the sixth dorsal vertebra, shown in Fig. 8, may serve as an
example. Hach has more or less the form of a ring, and presents for
consideration a body, arch, and processes.

The body or centrum (Owen), is a short cylinder or disc, which forms
the anterior part of the vertebra. Its superior and inferior surfaces are
nearly flat. Its anterior aspect is convex from side to side, but slightly
concave from above downwards. Its posterior surface forms part of the
ring, and is slightly concave from side to side. These vertical surfaces

10 VERTEBRAL COLUMN.

are pierced by numerous small foramina for the passage of blood-ves-
sels, one or two of which foramina situated near the middle of the pos-
terior surface are much larger than the others.

The arch consists of two symmetrical portions which spring, one on
each side, from the posterior surface of the body, and meet in the
middle line behind. The anterior part of each half, rounded and nar-
row, is called the pedicle ; the posterior part is broad and flat, and is
called the damina (neurapophysis, Owen). The concavities on the
upper and lower borders of the pedicles are named notches, and consti-
tute by the apposition of those of contiguous vertebrae, the intervertebral
foranuna, a series of rounded apertures, which communicate with the
vertebral canal, and transmit the spinal nerves and blood vessels.

The spinous process (neural spine, Ow.) projects backwards from the
arch in the middle line. The éransverse processes (diapophyses, Ow.),
placed one on each side, project outwards from the anterior part of the
arch. The articular processes (zygapophyses, Ow.), two superior and
two inferior, project upwards and downwards from a point near the
junction of pedicle and lamina. Their articular surfaces, coated with
cartilage, in the superior pair look backwards, and in the inferior for-
wards, so that the former face the latter in adjoining vertebre.

The foramen is bounded anteriorly by the body, posteriorly and later-
ally by the arch. The series of rings thus formed, united by ligaments,
constitutes the ewral canal, in which the spinal cord is contained.

Texture-—The bodies of the vertebrae are almost entirely composed
of spongy substance, the surface being covered with only a thin layer
of compact tissue. Venous canals, commencing at the larger foramina
behind, traverse the cancellated structure. ‘The arch and processes
contain a much smaller proportion of spongy substance, being covered
with compact tissue of considerable density in some places.

GROUPS OF VERTEBRA.

The vertebra are divided into five groups, named from thé regions
which they occupy, cervical, dorsal, lumbar, sacral, and coceygeal.

Cervical Vertebrz.—These are seven in number. The first and
second are so peculiar in form, as to require a separate description.
The following characters belong to the five lower vertebree.

Fig. 5.—Tuirp CErvica VERTEBRA. (A. T.) 4

A, from above and slightly from behind; b, from
the side. 1, the body ; behind a, the pedicle and
inter-vertebral notch ; 3, lamina ; 4, vertebral ring, of
a triangular form ; 5, bifid spinous process; 6, 6%,
transverse process—6, posterior, 6*, anterior tubercle ;
a, foramen in the transverse process transmitting the
vertebral artery; 7, 7’, articular processes—7, the
superior, 7’, the inferior.

The body is small and broader from side
to side than from before backwards. — Its
superior surface is transversely concave from
the upward projection of its lateral margins,
and is sloped down anteriorly. The under
surface on the contrary is rounded off at the
sides, while its anterior margin forms a marked projection downwards.

CERVICAL VERTEBRA. 11

The /amine are long and flat. The superior notches are deeper than
the inferior.

The spinous process is short, horizontal, or only slightly depressed,
and bifid ; that of the seventh, however, is longer than the others, and
terminates in a tubercle, which is readily felt below the skin, hence the
name vertebra prominens, applied to this vertebra.

The lateral parts usually called transverse processes are short and
bifid, presenting thus at their extremities two tubercles, anterior and
posterior, which are named respectively by Owen, parapophysis and
diapophysis. Hach process is deeply grooved superiorly for the spinal
nerves,and at its base is perforated vertically by a round foramen, through
which in the upper six the vertebral artery and vein pass. It is united
with the rest of the vertebra by two parts ; by the posterior, at the
place of junction of pedicle and lamina, like a dorsal transverse pro-
cess ; by the anterior, to the body of the vertebra, in the same line with
the heads of the ribs. The transverse process of the seventh vertebra
is large but not bifid, and only slightly grooved.

The articular processes are large and flat. Their articular surfaces
are oblique, the superior, looking backwards, upwards and slightly
inwards ; the inferior forwards, downwards and slightly outwards.

The foramen is triangular and larger than in the dorsal or lumbar
vertebree.

The first Cervical Vertebra, or Aflus, differs remarkably from the
others, by the absence of a body and spinous process, having the form
merely of a large ring with articular and transverse processes.

Fig. 6.—Attas VerTEBRA, FROM ABovE.(A.T.) § Fig. 6.

1, the anterior arch, with a tubercle in
front ; 4, the posterior part of the ring, with
5, an indication of a spinous tubercle ; 4’, the
anterior part of the ring, containing the odon-
toid process, and indicating in front of 4’ the
smooth surface on which the process moves
in rotation ; 6, the transverse process with a
slight indication of division into two tubercles ;
7, the condylar articular process; + inside
it indicates the rounded tubercle to which the
transverse ligament is attached ; a, the foramen
in the transverse process ; 6, the groove on the
posterior arch for the vertebral artery.

The interioz of the ring is wider posteriorly than anteriorly. Its
posterior part corresponds to the foramina of the other vertebre ; its
narrower anterior part is occupied by the odontoid process of the axis,
and in the recent state is separated from the posterior by the transverse
ligament. In front of the ring is the anterior arch, on the anterior
aspect of which is a small tubercle, and on the posterior a smooth
surface for articulation with the odontoid process. At the sides of the
ring are the dateral masses, which are thick and strong, bearing the
articular processes superiorly and inferiorly, and extending outwards
into the transverse processes. The articular processes differ from those
of other vertebree in being situated in front of the places of exit of the
nerves. ‘The superior are oval, converging in front, with cartilaginous
surfaces concave from before backwards, and looking upwards and
inwards. At the inner margin of each is a smooth rounded tubercle,
to which the transverse ligament is attached. The inferior articular

12 VERTEBRAL COLUMN.

processes are smaller than the superior, flat, nearly circular, looking
downwards and slightly inwards.

The posterior arch presents in the middle line a rough elevation, the
rudiment of a spinous process. The rest of the arch is thick and
round, but at its junction with the lateral masses, it is hollowed out
superiorly, so as to form a smooth transverse groove, in which lie the
vertebral artery and first spinal (sub-occipital) nerve. It is sometimes
converted into a foramen by a small arch of bone, and corresponds to
the notches of the other vertebrae.

The transverse processes are larger and project further outwards than
those of the subjacent vertebrae. They are flattened from above down-
wards, and have the foramen for the vertebral artery at their roots.
Their extremities are not bifid, but broad and rough.

The Second Vertebra.— Avis (vert. dentata) forms a pivot on which
the head with the first vertebra rotates.

The body is characterised by the presence of a large blunt or tooth-
like process called odontov (proc. dentatus). This consists of an enlarged
part termed the head, and a lower part
or neck. It presents in front a smooth
surface for articulation with the atlas, and
behind a smooth groove to receive the
transverse ligament. ‘The lower surface

Fig. 7.—Tuu Axis Vertepra. (A. T.) 3

A, seen from above and behind ; B, seen from the
right side. 1, the body ; 4, the vertebral ring
or foramen ; 5, the spimous process, bifid and very
large ; 6, the transverse process ; 7, the superior
articular process ; 7’, the inferior oblique articu-
lar process ; 1* in A, is placed at the side of the
odontoid process ; in B, in front of it, marking the
smooth surface of articulation with the anterior arch
of the atlas.

of the body resembles that of the suc-
ceeding vertebrae. Its anterior surface
presents a low median vertical ridge, with
a depression on each side.

The superior articular surfaces placed like those of the atlas in front
of the notch, lie close to the base of the odontoid process, partly on the
body and partly on the arch of the vertebra. These surfaces look
upwards and slightly outwards. The inferior articular processes are
similar in form and position to those of the succeeding vertebrae.

The spinous process is very large, rough, deeply bifid, and grooved on
its inferior surface. The /aminc are very thick and strong.

The transverse processes are short and scarcely grooved and bifurcated.
The foramen for the vertebral artery is inclined obliquely downwards
and inwards.

Dorsal Vertebrz.—These are twelve in number, and support the
ribs.

The body as seen from above is somewhat heart-shaped ; its antero-
posterior and transverse diameters are nearly equal.

It is specially characterised by the presence, at the place where it
joins the arch, of depressed articular surfaces for the heads of ribs. In

DORSAL VERTEBRA. 13

the greater number of instances, there are two costal surfaces on each
side,—one on the superior, the other on the inferior border,—so placed
that each completes, with that of the adjacent vertebra, a cavity for the

Fig. 8.—Srxtu Dorsan Vertesra. (A. T.) 3

A, viewed from above; B, viewed from the
right side. 1, the body ; 2, the pedicle ; 3, the
lamina; 4, vertebral ring, nearly circular ; 5,
spinous process; 6, transverse process ; 7, 7’,
superior and inferior articulating processes ; ¢, c’,
superior and inferior facets on the body for the
articulation of the head of the rib ; d, facet, on
the transverse process for the articulation of the
tubercle of the rib.

head of one rib. The body of the first
dorsal vertebra is, however, distinguished
by having on each side, near its upper
border, a complete articular surface for
the head of the first rib, besides a smaller
surface on the lower border for one
facet of the second rib. On the bodies
of the tenth, eleventh, and twelfth ver-
tebree, there is only one costal surface
for the corresponding ribs; that on
the tenth vertebra is usually complete,
when there is necessarily no costal sur-
face at the lower border of the ninth vertebra, but only one such
surface, a demi-facet at its upper border for the ninth rib.

The famine broad and flat are imbricated or sloped one pair over
another like tiles on a roof. The superior notches are very shallow, the
inferior comparatively deep.

The spinous process, described as bayonet-shaped, is three-sided, and
terminates in a slight tubercle. It is longest and has the greatest
downward inclination in those toward the middle of the series.

The transverse processes are directed outwards and backwards, and
terminate in a rough tubercle which presents anteriorly a smooth
surface for articulation with the tubercle of a rib. This articular
surface is wanting on the eleventh and twelfth vertebree. In several of
the lowest vertebra the extremity of the transverse process when looked
at from behind presents three slight elevations, named the external,
internal, and inferior tubercles. These are best marked on the twelfth
vertebra, and correspond respectively to the transverse, mammillary,
and accessory tubercles to de afterwards noticed on the lumbar vertebree.
(See Figs. 9 and 10, e, f, 6.)

The articular processes have their cartilaginous surfaces nearly
vertical. Those of the superior processes look backwards, slightly
upwards and outwards, those of the inferior look forwards, slightly
downwards and inwards. But the superior articular processes of the
first dorsal vertebra are similar to those of the cervical, and the inferior
of the twelfth dorsal to those of the lumbar vertebree.

The foramen is nearly circular, and is smaller than in the cervical or
the lumbar region.

Lumbar Vertebre.—-These are five in number, larger than the

14 VERTEBRAL COLUMN.

mane vertebree, and distinguished by the absence of costal articular
surfaces.

Fig. 9.—Turrp LumbBarVertesra.(A.T.) §

A, from above ; B, from the right side.
1, the body; 2, the pedicle and inter-
vertebral notch ; 3, the lamina; 4, the
vertebral ring, somewhat triangular; 5,
the spinous process ; 6, transverse process ;
7, 7,’ superior and inferior articular pro-
cesses ; ¢, the mammillary tubercle, appa-
rently on the superior articular process ;
f, the accessory tubercle, between the ar-
ticular and transverse processes.

The body has a greater diameter
transversely than from before back-
wards, and viewed from above or
below its surface presents a reni-
form outline. That of the fifth
lumbar vertebra is considerably
deeper in front than behind.

The damine are shorter, deeper,
and thicker than those of the
dorsal vertebree. The superior
notches are shallow, the inferior
deep.

The spinous process projects horizontally backwards. It has con-
siderable breadth from above
Fig. 10. downwards, and is thickened and

rough along its posterior edge.

Fig. 10.—Two Lowrr Dorsan AND Two
Urerer Lumbar Vertesre. (A. T.)

with portions of the eleventh and twelfth
ribs of the right side : viewed from behind,
chiefly to show the relations of the trans-
verse processes and adjacent tubercles.
1, body of the eleventh dorsal vertebra ;

, spinous process of the second lumbar ;
6, costal tubercle of the transverse process ;
7, 7’, superior and inferior articular pro-
cesses ; e¢, mammillary, and jf, accessory
tubercle ; c, ce, tworibs. These indica-
tions are placed only on the alternate verte-
bree to avoid crowding the figure.

The transverse processes, long
and somewhat spatula-shaped,
project directly outwards. Their
extremities lie in series with the
external tubercles of the lower
dorsal transverse processes, and
with the ribs. Behind each at its base is a small process pointing
downwards, which corresponds to the inferior tubercles of the dorsal trans-
verse processes, and is called the accessory process (anapophysis, Owen).

SACRAL VERTEBRA. 15

The articular processes are thick and strong. Their articular surfaces
are vertical ; those of the superior pair concave, look backwards and \ —
inwards, those of the inferior, convex, look forwards and outwards. — Pa
The superior pair are further apart than the inferior, and embrace the
inferior pair of the vertebra above them. rom each superior articular
process, a tubercle projects backwards, which corresponds to the
internal tubercles of the dorsal transverse processes, and is called the
mammillary process (metapophysis, Owen).

The foramen is large and triangular, or widely lozenge-shaped.

Sacral Vertebre.—These by their union in the adult, form the
os sacrum, but in youth they present the elements of five distinct
vertebree. The sacrum is placed below the last lumbar vertebra, and
articulates laterally with the two ossa innominata, thus completing
together with the coccyx the wall of the pelvis above and behind. The
uppermost vertebra is the largest, those which follow become rapidly
smaller and the fifth is rudimentary. Hence the sacrum has the form
of a triangle with its base directed upwards. It is concave and smooth
in front, convex and uneven behind. The direction of its surfaces is
very oblique, its ventral aspect looking somewhat downwards, and
forming above at the place where it joins the last lumbar vertebra, the
projection termed promontory. The dorsal or posterior surface looks
slightly upwards.

Fig. 11.—Sacrum or tHE MALE, VIEWED FROM
BEFORE. }

1, 1, four transverse ridges, indicating the place of
original separation of the bodies of the five sacral
vertebre ; 2, anterior sacral foramina ; 3, 4, lateral
surface ; 5, a notch which, with the coccyx, forms a
passage for the fifth sacral nerve ; 6, oval surface of
the upper part of the sacrum for articulation with the
body of the last lumbar vertebra ; 7, superior articular
processes ; 8, inferior oval surface for articulation
with the coccyx ; +, inferior lateral angle.

he ventral surface is concave from above downwards, and slightly
so from side to side. It is traversed horizontally by four ridges, which
indicate the places of union of the bodies of the five vertebrae, and at
the extremities of which are situated on each side four foramina called
anterior sacral. These foramina widen externally into grooves, and
diminish in size from above downwards.

The dorsal surface is convex, very uneven and somewhat narrower
than the ventral. It presents along the median line four small
eminences, the spinous processes, usually more or less connected, so as
to form a ridge. Below the last spinous process is a triangular opening,
the termination of the spinal canal, the lateral margins of which are
formed by the imperfect laminz of the fifth sacral vertebra, and present
a pair of tubercles, the sacral cornua, which project downwards, and
articulate with the cornua or horns of the coccyx. On each side of the
ridge of spines the surface is smooth and hollowed in the position of
the united laminz, and beyond this surface are two rows of eminences,
the inner of which corresponds to the articular and mammillary pro-
cesses of the lumbar vertebrae, the outer to the transverse processes.

16 VERTEBRAL COLUMN.

In the groove between the two rows are placed the four posterior sacral
foramina, which are smaller than the anterior.

The part of the sacrum external to the foramina constitutes the
lateral mass, and is broad and thick superiorly, but narrowed inferiorly.
The outer aspect of the upper part presents in front a large uneven

Fig. 12.—Sascrum anp Coccyx oF THE
MALE VIEWER FROM BEHIND. (A.'T.) }

1, Body of the first sacral vertebra ; 4, 4,
sacral canal ; and behind this, the series of
four united lamin and spinous processes ;
6, 6’ line of tubercles corresponding to
transverse processes ; 7, 7’, line of articu-
lar processes, with four adjacent posterior
sacral foramina; JZ, 2, auricular or iliac
articular surface ; in the coccyx, c, body
of the last vertebra ; ¢, transverse process ;
7, cornu or superior articular process.

surface, covered in the recent
state with cartilage, which articu-
lates with the ilium, and is called
from its shape the auricular sur-
Jace: behind this it is rough and
very uneven, for the attachment
of ligaments. Lower down, the
margin becomes narrowed and
sinuous, terminating in the pro-
jection called the mferior lateral
angle, below which the breadth of the bone is suddenly contracted so
as to form a notch with the adjacent part of the coccyx.

The base or upper surface of the first vertebra bears considerable
resemblance to the upper surface of the last lumbar. In the middle
it presents the reniform surface of the body, behind which is the
triangular aperture of the sacral canal, bounded by the depressed

Fig. 13. Fig. 13.—Uprrer Svurrace or Bask oF THE
Sacrum oF A Matz. (A. 7.) 3

2

1, the body ; 4, the foramen, ring, or sacral
canal ; 5, the spinous process of the first sacral
vertebra; 6, the part corresponding to a
transverse process, in front of which is the
large lateral mass; 7, 7’ the superior and
inferior articular processes; ec, the mam-
millary tubercle ; jf, the accessory tubercle,
slightly seen.

Z ath ge
Nl“ i
A(Hifsen wee
=

“SSL

lamine. On each side of the aperture is an articular process, exactly
resembling the superior process of a lumbar vertebra. In front of this
is a groove which forms part of the last lumbar intervertebral foramen.
The external portion of the base presents posteriorly an eminence
corresponding to the lumbar transverse process, and in front of that
a large smooth curved surface, continuous with the iliac fossa of the
pelvis.

COCCYGEAL VERTEBR2. 7

The lower end or apex, formed by the small inferior surface of the
body of the fifth sacral vertebra, is transversely oval, and articulates
with the coccyx.

The sacral canal is three-sided, curved with the bone, and gradually
narrowed as it descends. It opens below on the posterior surface of the
bone between the sacral cornua where the lamin of the last sacral
vertebree are imperfect. From this canal there pass outwards in the
substance of the bone four pairs of intervertebral foramina, closed
‘ externally by the lateral masses, but opening on the surface by the
anterior and posterior sacral foramina.

Differences in the sexes—The sacrum of the female is broader in proportion to
its length than that of the male; it is also flatter, and usually inclines backwards
from the direction of the lumbar vertebre to a greater extent than in the male.
But the curvature varies considerably in different skeletons,

Varictics.—The sacrum not unfrequently consists of six vertebra, and some-
times, though rarely, of only four. Occasionally the bodies of the first and second
vertebre are not united, though complete union has taken place in every other
part, or the first vertebra may present on one side the usual sacral form, while
on the other it has the appearance of a lumbar vertebra, and is not united to
the next (see fig. 21, 11,2’), a peculiarity connected with the oblique form of pelvis.
Instances also occur, in which it presents, on both sides, characters intermediate
between those of sacral and lumbar vertebra. The lower end of the sacral canal may
be open to a greater extent than usual ; it haseven been found open throughout.

Coccygeal vertebrz, or coccyx.—These are very rudimentary ver-
tebree, commonly four, sometimes five, seldom only three in number.
The first of the series is considerably broader than the others. It pre-
sents superiorly on the part corresponding to the body an oval concave
surface which articulates with the lower end of the sacrum ; two small
processes, termed cornwa, which project upwards from its posterior
margin, connected by ligaments with the sacral cornua ; and a short

Fig. 14.—Four CoccyeraAL VERTEBRE, SEEN FROM BEFORE.—F ROM A
Mate Supsect or Mippie Ace (A. T). §.

The upper piece is separate from the second ; the three lower are
united together in one piece, and separated only by grooves. 1
above the middle or body of the first coccygeal vertebra ; 1’ below the
fourth piece ; 6, the transverse portion ; 7, the superior articulat-
ing tubercle.

process, which projects from each side, and usually forms,
with the inferior lateral angle of the sacrum, a notch for
the fifth sacral nerve, but in some cases unites with that bone to form a
fifth sacral foramen.

The remaining three coccygeal vertebree are much smaller than the
first, and correspond solely to vertebral bodies. When separate, the
second piece presents an upper and lower flattened surface. The third
and fourth pieces are mere rounded nodules. In middle life, the first
piece is usually separate, while the three lower pieces are united into
one, the original separation being indicated by transverse grooves.

In advanced life, the coccygeal vertebra, having been previously
joined into one bone, become also united to the sacrum. ‘This union
occurs at an earlier age and more frequently in the male than in the

female, but it is subject to much variation.
VOL, I. Cc

18

VERTEBRAL COLUMN.

Fig. 15.—VERTEBRAL CoLuMN or AN ApuLT Mate,
SEEN FROM BEHIND (A. T.). 3

C 1 to above D 1, the seven cervical vertebra ;
D1 +o above L 1, the twelve dorsal vertebrae ; L 1
to above § 1, the five lumbar vertebr ; 5 1 to above
CO 1, the sacrum ; CO 1, and below, the four coccy-
geal vertebr. The transition in the form of the trans-
verse processes and tubercles is well marked in this
specimen.

The vertebral column as a whole.—
The vertebral column may be regarded as a
central column upon which the other parts
of the skeleton are arranged. Superiorly it
supports the skull, laterally the ribs, through
which also it receives the weight of the
upper limbs, and near its lower extremity it
rests upon the pelvic bones, by which it
transmits the weight of the body to the lower
limbs. It is a pillar of support to the rest of
the skeleton, and protects the spinal cord
by enclosing itina bony canal. Its average
length is about 28 inches.

When seen in profile the column presents
four curves, directed alternately forwards
and backwards,—forwards in the cervical
and lumbar regions, backwards in the dor-
sal and sacral. The cervical and lumbar
convexities are produced by the greater
thickness of the anterior over the posterior
parts of the intervertebral discs, and in the
case of the latter also by the greater depth
of the fifth lumbar body anteriorly, while in
the dorsal and sacral concavities, the bodies
of the vertebre are thinner in front than
behind. These curves are connected with
the maintenance of the erect posture, and
give to the column greater elasticity and
security from injury than it would have
were it perfectly straight. In the dorsal
region also there is very frequently a slight
degree of lateral curvature, the convexity of
which, in most cases, is directed towards
the right side, and is probably connected
with the greater use made of the right than
of the left arm.

Viewed in front, the bodies of the vertebree
are seen to become broader from the axis
to the first dorsal, then slightly narrower
to the fourth dorsal, and from that ver-
tebra they gradually widen to the base of
the sacrum. The width between the ex-
tremities of the transverse processes is con-
siderable in the atlas ; small in the axis, it

OSSIFICATION OF THE VERTEBR2.

becomes greater as far as the first dorsal
vertebra, thence it is again gradually
contracted as far as the last dorsal, and
becomes suddenly much greater in the
lumbar region.

In a lateral view the antero-posterior
diameter of the bodies increases in
descending through the dorsal and
lumbar regions,

Viewed from behind the spines
eccupy the middle line. On each side
are the vertebral grooves, corresponding
to the lamine, and bounded externally
in the cervical and dorsal regions
by the transverse processes, and in
the lumbar by the mammillary pro-
cesses. Along each groove is a series
of spaces between the lamine, which,
in the natural condition, are filled
up by the yellow ligaments. The
extent of these intervals is very trifling
in the neck and in the greater part
of the back ; it increases in the lower
third of the dorsal, and still more in
the lumbar region. The interval be-
tween the occipital bone and the arch
of the atlas is considerable, and so is
that between the last lumbar vertebra
and the sacrum.

Fig. 16.—TxHe VERTEBRAL CoLUMN VIEWED FROM
THE Lert Srpzr. (A. 7.)

The letters and numbers indicate the several
vertebree. The antero-posterior curvatures of
the column are shown, together with the shape
and size of the bodies and intervertebral spaces,
the form and transitions of the transverse and
spinous processes, and the differences in the
costal articulating surfaces.

OSSIFICATION OF THE VERTEBRA.

The Vertebre in general.—The ossifi-
cation of each vertebra proceeds in cartilage
from three principal centres, one for the
main part of the body, and one on each
side for the arch and processes, together
with a part on each side of the body. The
lateral centres appear about the 7th week,
that of the body very soon afterwards. From
these centres the ossification extends gradu-
ally outwards, so as at last to form the greater
part of the vertebra. That of the body does
not pass, however, in the dorsal vertebre,
the place of articulation of the head of the
rib, leaving on each side a portion of the
body which is formed from the lateral centre,

c 2

Fig. 16.

19

20 VERTEBRAL COLUMN.

and is separated up to the third year by a narrow cartilaginous interval—the
neurocentral suture. It would appear further, that while ossification in the centres
of the arches commences first in the upper or cervical vertebrae, the osseous
centres of the bodies appear earliest in the lower dorsal vertebra.

At the time of birth most of the vertebre consist of three osseous pieces, cor-
responding to the three original ossific centres. In the first year of infancy the
osseous laminze of opposite sides become united in a number of the vertebra, but
notinall. The spinous processes, remaining cartilaginous for a time, are gradually
completed by the growth of the cartilage and the extension of the bone into

Fig. 1/. Fig. 17.—OssiFicatIon oF THE VER-
TEBRE. (R. Quarn.)

A, feetal vertebra, showing the three
primary centres of ossification ; 1, 2,
for the pedicles, lamin, and processes ;
3, for the body.

B, dorsal vertebra from a child of
two years ; 1 & 2 are seen to have en-
croached upon the body at * the neuro-
central suture and into the articular
and transverse processes, and to have
united behind in the spinous process,
leaving the ends cartilaginous.

C, dorsal vertebra at about sixteen or
seventeen years, showing epiphyses on
the transverse processes, 4 & 5, and
spinous process, 6, and the upper epi-
physial plate of the body, 7.

D & 8, parts of a lumbar vertebra of
about the same age, showing, in addi-
tion to the foregoing, 8, the lower epi-
physial plate of the body ; 9 & 10, the
epiphyses of the mammillary tubercles.

them, and at the same time, by the ossific extension of the transverse processes and
other parts, the vertebra gradually attain to nearly their full size and shape about
the age of puberty. At different periods subsequent to this, five sets of epiphyses,
or supplementary centres of ossification, are added. Three of these are small
portions of bone, placed on the tips of the spmous and transverse processes : the

Fig. 18.—OssrricaTion oF THE ATLAS.
(R. Quarn. )

A, befcre birth ; 1 & 2, lateral centres
of ossification ; the anterior arch is carti-
laginous.

B, in the first year ; 1 & 2, as before ;
3, ossific centre in the anterior arch.

Fig. 19.—Osstrication oF tHE AXIS
AS SEEN IN Front. (R. Quary.)

A, from a feetus of seven months; 3,
the centre for the body; 4 & 5, two
centres for the base of the odontoid process.

B, shortly after birth ; 1 & 2 the lateral
centres ; 3, centre for the body ; 6, the
two centres for the odontoid process now
united,

other two are thin circular plates, one on the upper, the other on the lower
surface of the body, chiefly at its cireumference. In the lumbar vertebra two
other epiphyses surmount the mammillary processes. The transverse process of the
first lumbar vertebra is sometimes observed to be developed altogether from a
separate centre. Most of the anterior divisions of the cervical transverse pro-
cesses are ossified by the extension into them of osseous substance from the
neighbouring posterior part of the process and from the arch; but that of the

OSSIFICATION OF THE VERTEBRZ. 21

seventh usually presents 2 separate osseous nucleus, and small nuclei have also
been observed by Meckel in those of the second, fifth, and sixth vertebra. These
epiphyses generally appear from the eighteenth to the twentieth year, and are
not wholly united to the rest of the vertebra before the twenty-fifth year.

The Atlas & Axis.—The ossification of the atlas and axis differs consider-
ably from ‘that of the other vertebre. In the atlas, the body being absent, the
anterior arch is formed by a strip of cartilage in which ossification, commencing
by one or two centres, only appears in the course of the first year after birth. The
neural arch, together with the processes, is formed from two lateral centres cor-
responding with those of the other vertebrz, and which begin to ossify about the
7th or Sth week. Their union posteriorly occurs in the 8rd year, and is frequently
preceded by the formation of a distinct spinal nucleus. Their union with the
nucleus of the anterior arch does not take place till the 5th or 6th year.

In the axis the arch and processes are formed from two centres corresponding
to those of the other vertebrae, and appearing about the 7th or 8th week. Ossifi-
cation begins in the body about the 6th month, from one or sometimes two
centres, occupying the lower part of the common cartilage of the body and odon-
toid process. In the upper part of this cartilage, a little later, two collateral
centres appear for the odontoid process; these soon unite into one, and become
ossified to the body of the axis in the 3rd year. There is frequently also a dis-
tinct centre in the apex of the process. (Humphry.) This separate ossification
of the odontoid process is important in connection with the view that it is
the displaced body of the atlas,

Sacral Vertebrze.— Each of the sacral vertebree presents three primary centres
of ossification, one in the body and a pair in the arch. The centres of the bodies

Fig. 20.—OsstrrcaTIon OF THE Sacrum. (R. Quarn.)

A, sacrum of a foetus before six months, seen from the front, showing the ossific centre
in the body of each vertebra, from 1 downwards.

L, at birth; 2,2, additional centres for the lateral masses.

©, about twenty-three years ; 3, 3, epiphysial plates still visible above and below the first
vertebral body, the fissures still remaining between the first and second and the second
and third lateral masses ; 4, 4’, lateral epiphysial plates.

D, upper surface of first sacral vertebra at four or five years, 1, and 2, as in A and B. (A.T.)

A & B, nearly full size; C, one-fourth ; D, one-third.
of the first three vertebra appear about the 8th or 9th week, those of the two
following vertebree somewhat later. The lamine begin to ossify about the 6th
month, but the time of union with the bodies differs in the different vertebree ;
taking place as early as the 2nd year in the lowest, but not till the 5th or 6th
year in the uppermost. In each of the first three vertebrae, and sometimes only
of two, the anterior part of the lateral masses on each side is formed from an
additional nucleus which appears at the outer margin of the anterior sacral
foramen from the 6th to the 8th month. These unite to the bodies later than
the arches. In the case of the two lower vertebre, the lateral masses are formed
by extension of ossification from the primary lateral nuclei. On the body of

.

22 VERTEBRAL COLUMN,

each vertebra, epiphysial plates are formed after puberty, as in other vertebra,
and two flat irregular plates of bone are added to each lateral surface of the
sacrum, the uppermost of which extends over the sides of the first two or three,
while the lower connects the remaining two. These appear from the 18th to the
20th year, and are united about the 25th. The bodies of the sacral vertebra are at
first separated by intervertebral plates, but about the 18th year, in the case of
the lower vertebra, ossification begins to extend through these plates and the
epiphyses, so as completely to unite the adjacent bodies. The ossific union
of the first and second bodies does not take place till the 25th year or later
Previous to this, the lateral masses have coalesced nearly in the same order as
the bodies.

The deficiency of the spine and dorsal part of the lamine usually existing in
the fifth sacral vertebra, and not unfrequently extending to the fourth, but more
rarely to the third, may be attributed in part to the non-extension of ossification
in that direction: but such varieties of form, like many others to which the
sacral vertebrae are subject, are probably intimately connected with the nature
and development of the formative matrix of the bones. The more completely
open state of the sacral canal posteriorly found in cases of spina-bifida is un-
doubtedly connected with early morbid changes interfering with the natural
process of development.

Coccygeal Vertebree.—Each of the coccygeal vertebra is ossified from a,
distinct piece of cartilage,and usually from a single centre, but in the upper
sometimes from two centres. Ossification commences in the first generally about
the time of birth; in the second, from the 5th to the 10th year; in the third,
some time before, and in the fourth, some time after puberty. The ossific union
of the three lower coccygeal vertebrz occurs before middle life ; their union with
the first, and the union of this with the sacrum, belong to the later periods of life.

GENERAL AND SERIAL HOMOLOGY OF THE VERTEBRA,

The study of the various forms presented by the parts of the vertebral column,
and of its relation to the rest of the skeleton in man and animals, as also
of its development in the foetus, has led to the formation of the general
views of homology referred to in the introduction. These views originated, in
somewhat different forms, mainly with Oken, Carus, Geoffroy St. Hilaire, and
Owen ; and, with various modifications and extensions by more recent writers,
as Goodsir, Huxley, Gegenbaur, St. George Mivart, and Flower, are now admitted
by almost all anatomists, in some shape or other, as the basis of a morphological

Fig. 21.—Virws or tur Dirrerent VERTEBRE FROM ABOVE TO ILLUSTRATE THEIR
Homouoaies. (A. T.)

1, atlas; 2, axis; 3, sixth cervical; 4, seventh cervical with supernumerary ribs ;
5, middle dorsal; 6, upper dorsal, with costal arch and sternum attached; 7, middle
lumbar; 8, first lumbar with supernumerary ribs ; 9, lower lumbar ; 10, upper sacral ; 11,
upper sacral vertebra, presenting the lumbar form on the right side, as in the oblique
pelvis ; 12, fourth sacral vertebra in & young subject ; 13, four coccygeal vertebrie.
In the several figures the parts are indicated by letters as follows, viz., in 1, s, spine 3.
Ny neural arch ; c’, the space occupied by the processus dentatus, or displaced body ;
h, anterior or precentral arch ; a7, superior articular process : in 2, ¢”, processus dentatus ;
ar, superior articular process ; z’ inferior articular process: in 3, c, centrum or body ;
¢, 2, superior and inferior articular processes : in 4, ¢, ¢, transverse processes ; v, 7, ver-
tebrarterial foramina ; co, moveable right supernumerary or cervical rib ; x, with a dotted
line marks the place where an anchylosed rib on the left side may be considered to be
superadded to the transverse process (diapophysis and parapophysis) of the vertebra : in 5,
¢, transverse process with costo-transverse facet ; cc, costo-central facet : in 6, 7, ver-
tebrarterial interval ; ct, costo-transverse, and cc, costo-central articulations ; co, first
rib: in 7, m, mammillary, and a, accessory tubercles ; ¢, transverse process : in 8, co,
co’, left and right supernumerary ribs : in 10, J, the lateral mass : in 11, /’, place of the
lateral mass, remaining undeveloped in this instance: in 12, ¢l, the transverse process
and lateral mass which unite with the corresponding parts above; f, /’, anterior and
posterior sacral foramina thus formed ; in 18, c, the centrum or body, which alone remains.
in the last coceygeal vertebra.

VERTEBRATE HOMOLOGIES. 23

doctrine of the construction of the skeleton. There is not, indeed, an entire
agreement among anatomists with respect to some parts of this doctrine ; but
still there is such a general acknowledgment of both the zoological and serial
homology of the parts composing the skeleton, that considerations of this kind

24 VERTEBRAL COLUMN,

cannot be entirely omitted in a work on human anatomy. At the same time, it
is obvious that the complicated nature of the subject, and the necessity for
frequent reference to details of comparative anatomy for its elucidation make it
impossible to enter fully into its consideration here, so that our remarks must be
limited to those points in which the views of homology haye the most immediate
bearing upon the knowledge of human anatomy. The accompanying views of
the several vertebrae and some of their varieties from above (in fig. 21) may assist
the reader in comparing their forms.

1. The series of centra or bodies, surrounding the primary axis of the noto-
chord, is complete in man, from the processus dentatus of the second vertebra to
the caudal extremity. In the head it is ascertained to be prolonged into the basi-
occipital and basisphenoid parts of the base of the skull. It is apparently absent
in the atlas, or rather the part corresponding to the centrum or body of that
vertebra is united with the body of the axis in the odontoid process : while the
anterior arch of the atlas belongs to a different series of parts, not yet accu-
rately determined, perhaps to the precentral or subcentral parts or hypapophyses.
The proofs of this view are derived mainly from, Ist, the remains of the noto-
chord having been actually traced in the foetus through the odontoid process
(and not through the anterior arch of the atlas) into the basioccipital bone ;
2nd, the separate ossification in cartilage of the odontoid process: and 3rd, the
existence in some animals, as the ormithorynchus and some reptiles, of a bone
corresponding to the odontoid process, in a separate condition, without any other
part representing the body of the atlas.

2, The series of neural arches is complete in the whole vertebral column of
man, with the exception of the three lowest coceygeal vertebrae, and in part
of the upper coceygeal and lowest sacral vertebree. The neural spines are also
complete in nearly the same vertebree as the arches. The spine is absent or little
developed in the atlas, bifid at its extremity in the next five cervical vertebra, but
simple in all the remaining vertebre in which it is present.

3. The articular processes, or zygapophyses, superior and inferior (ante-
rior and posterior in animals), correspond in their relations throughout the whole of
the vertebra in which they exist, with the exception of both of those of the atlas
and the superior of the axis. In these last mentioned vertebre the articular pro-
cesses are not in the series of zygapophyses, being situated at the place of union of
the pedicles with the bodies, or nearly in the place of the capitular articulation of
the ribs with the vertebral bodies, and therefore anterior to the place of exit of
the spinal nerves, instead of posterior to it as in the other vertebra. In the
sacral vertebrae the articular processes, existing as such in early life. come to be
in the adult united by anchylosis. In the three lower coccygeal vertebre they
are absent.

4, It is in the comparison of the parts known in human anatomy under the
general name of transverse processes, that the main difficulty of establishing
homologies exists. In all the cervical vertebre the processes so called are pierced
by a vertebrarterial foramen, and the most of them have two tubercles. Those of
the dorsal vertebra are for the most part simple, but are articulated at two places
with theribs. Atthese two places are situated processes, sometimes projecting in
animals to a considerable extent, which receive respectively the names of di-
apophysis and parapophysis ; the first (diapophysis) being the tubercular or costo-
transverse, the posterior or upper articulation of the rib: the second, or par-
apophysis, being the capitular or costo-central articulation, the lower or anterior,
of the rib, placed close to the body but separated from it by the neuro-central
suture. It is very generally admitted that the part in front of the vertebrar-
terial foramen of the cervical vertebra corresponds in series to the first part of a
rib; as is illustrated by the separate ossification of that piece of bone in the
seventh cervical vertebra in man, and by the occasional occurrence of more fully
developed cervical ribs in that situation.

The vascular passage in the dorsal region is between the neck of the rib
and the vertebra. In the lumbar vertebra the transverse processes are elongated
laterally, and at their root two other processes become apparent, viz., the mam-
millary or metapophysis, looking upwards in man or forwards in animals, and the

BONES OF THE THORAX. STERNUM. 26

accessory or anapophysis, directed downwards or backwards. Several circumstances
in the anatomy both of the bones and muscles, as well as the form and position of
occasional or supernumerary lumbar ribs, seem to indicate that the outer part of
the lumbar transverse processes is serially homologous with the first part of the
ribs, but so intimately combined with both diapophysis and parapophysis, and
the part lying between them, as to leave no arterial passage; but a groove
on the upper side is regarded by some as an indication of the place of separation.
In the sacral part of the column still greater departure from the form of
the transverse process of the upper vertebre takes place by the large develop-
ment and ossific union of the lateral parts. Throughout the whole five vertebra
recognised as sacral in man, this may be looked upon as occurring to some extent
in portions of the bones which are serially homologous with the combined
diapophysis and parapophysis; but in two at least, and perhaps in three of the
upper sacral vertebree, another lateral element appears to be interposed between
that combined transverse process and the iliac surface of articulation, constitut-
ing the greater portion of the large lateral mass of the sacrum, This element
is looked upon by some as serially homologous with part of a rib. (Retzius,
Miiller’s “‘ Archiv,” 1849; Miller “ Vergleich. Anat. der Myxinoiden ;* Owen,
“ On the Archetype. &c., of the Vert. Skeleton ; ” Aug. Miller, Millers “ Archiv,”
1853 ; Humphry, “ Treatise on the Human Skeleton ;” Goodsir, in ‘* Edin. New
Philos. Journ.,” 1857 ; Cleland, in “ Nat. Hist. Review,’ 1861 and 1863 ; Huxley,
‘Hunterian Lect. in Brit. Med. Journ.,’ 1869; St. George Mivart, in ‘“ Linn.
Trans.,” 1870, and “ Elementary Anatomy,’ 1873; Flower, ‘‘ Osteology of the
Mammalia,’ 1870 ; Gegenbaur, ‘‘ Grundzuge der Vergleich. Anat.,” 1870.)

With the exception of the anterior arch of the atlas already referred to, there
are no parts developed in the human skeleton which correspond with the hyp-
apophyses which occur in connection with the vertebral column of animals, such
as the “ chevron” bones below the caudal vertebree of cetacea, and the hemal
arches enclosing the main artery of fishes.

The similarity of some of the parts composing the skull to vertebre, or the
serial homology of the bones of the head and vertebrae, supposed by some
anatomists to exist, will be referred to hereafter.

IlL—THE THORAX.

The thoracic part of the skeleton consists of the dorsal vertebrae
already described, the sternum, the ribs, and the costal cartilages.

THE STERNUM OR BREAST-BONE.

The sternum is situated in the median line at the fore part of the
thorax. It is connected with the rest of the trunk by the cartilages of
the first seven pairs of ribs, and gives attachment to the clavicles. It
consists originally of six segments. The first of these usually remains
distinct up to middle life, and is called the manubrium or presternum ;
the succeeding four are united into one in the adult, and form the bod,
or mesosternum: the sixth generally remains cartilaginous up to the
period of puberty, and sometimes partially so even to advanced age,
constituting the ensiform process, or metasternum: in middle life it is
most frequently ossified and united by bone to the body.

The sternum is flattened from before backwards, and presents a slight
vertical curve with the convexity in front. It is of unequal width,
being broad at the upper part of the presternum, considerably narrower
at the lower end of that portion and in the first segment of the meso-
sternum, somewhat wider near the lower end of that portion, and finally
compressed and narrowed near the junction with the metasternum. It
eet of light cancellated texture, with a thin covering of compact

one.

26 BONES OF ‘THE 'THORAX,

The presternum is the thickest part of the bone. Its anterior sur-
face presents a slignt median elevation, its posterior is smooth and

Fig, 22.—Tue SrerNuM OF A MIDDLE-AGED
Via (ASL) ay

A, from before, 1, 2, 3, 4, 5, 6, & 7, the
articular surfaces for the corresponding
costal cartilages ; 8, manubrium or upper
piece, still separate from the body; 9,
middle of the body; 10, ensiform por-
tion, osseous, and united to the body ; 11,
inter-clavicular notch ; 12, articular notch
for the clavicle. J

B, the same sternum viewed from the
right side, showing the general convexity
of the bone forwards. The different facets
of articulation of the clavicle and costal
cartilages will be distinguished by their
position in comparing the figure B. with A.

somewhat concave. Its upper bor-
der is divided into three deep
notches ; the middle one is named
the incisura semilmaris, or inter-
clavicular notch ; the lateral ones
form two depressed articular sur-
faces directed upwards and out-
wards, for articulation with the
clavicles. Each lateral border pre-
sents superiorly close to the clavi-
cular surface, a rough triangular surface, which unites with the cartilage
of the first rib. Below this the bone slopes inwards, and at its inferior
angle presents a small surface, which with a similar one on the meso-
sternum forms a notch for the cartilage of the second rib. The lower
margin is straight and united by intervening cartilage to the upper
margin of the mesosternum.

The mesosternum is marked on its anterior surface by three slight
transverse elevations at the lines of junction of its four component
parts. Its posterior surface is comparatively smooth. Each lateral
margin presents five notches for the reception of costal cartilages, and
a small surface superiorly, which, with the similar depression on the
presternum, forms the notch for the second costal cartilage. The
notches for the third, fourth, and fifth costal cartilages are opposite the
lines of junction of the four segments of the body of the sternum ;
those of the sixth and seventh are placed close together on the sides of
the inferior segment, that for the seventh being frequently completed
by the ensiform cartilage. The lower part of the presternum is some-
times pierced in the middle line by a considerable hole.

The metasternum, ensiform process, or xpphisternum, is a thin spatula-
like process projecting downwards between the cartilages of the seventh
ribs. It is subject to frequent varieties of form ; being sometimes bent
forwards, sometimes backwards, often forked, and sometimes perforated.

The sternum is subject to many varieties. It is sometimes divided vertically in
the whole or pari of its length, It is not unfrequently much shorter than usual,

THE RIBS, 27

and indented at its lower part, as occurs especially from the pressure of the
cobbler’s last.

Two small nodules of bone, ossa suprasternalia, have been found in some rare
cases at the sides of the incisura close to the clavicular notches, sometimes being
united by bone, at others by ligament to the sternum. (Breschet, ‘‘ Annales des
Sciences Naturelles,” 2nd series, v. 10, p. 91; and Luschka, “ Die Halsrippen und
die Ossa suprasternalia,’ Vienna, 1859.) Their position is indicated by the
asterisks (**) in figure 26, E. They derive an additional interest from the occur-
rence of suprasternal bones in some animals.

THE RIBS.

The ribs (cost), twelve in number on each side, constitute a series of
arched and highly elastic bones, which extend outwards and forwards
from the vertebral column, and form the lateral walls of the thorax.
Their anterior extremities give attachment to cartilaginous prolonga-
tions—the costal cartilages, the first seven pairs of which pass forward

Fig. 25.

Fig. 23.—Tue Finsz, Srxtx, anp Tweurrn Riss or tae Riaut Srpz. (A. T.) §

A, the sixth seen from above and the outer side; B, the same rib viewed from below
and within ; C, the first rib viewed from above and without ; D, the twelfth rib viewed
from above and within.

1, the head in C & D, the inter-vertebral ridge in B ; * *, the costo-central facets 5,
2, the neck ; 3, the tubercle, in B presenting the rough tubercle and the smooth facet.
for articulation with the transverse process ; 4, the lower border with the ridge and sub-
costal groove ; 5, the upper border ; 6, the oval pit for the attachment of the costal
cartilage ; 7, in the first rib, C, the scalene tubercle or spine, and near it the smooth
groove for the subclavian artery.

to the sternum. On this account the first seven pairs of ribs are called
sternal, and the remaining five pairs asternal ribs. Of these asternal
ribs each of the upper three has its cartilage attached along its superior
border to the cartilage of the rib above it, while the last two being
entirely free from such attachment are called floating ribs.

General characters of the ribs.—These are best marked in the
ribs near the middle of the series. The posterior extremity is thick-
ened, and is termed the head or capitulum ; it presents a superior and
an inferior oblique articular surface for articulation with the bodies of

‘28 BONES OF THE THORAX.

two vertebree, and, between them, a slight ridge, to which the inter-
articular ligament is attached. At a little distance from the head, and
separated from it by the slightly constricted neck, is the tubercle, which
is directed backwards, and presents a smooth surface for articulation
with the transverse process of the inferior of the two vertebree with
which the head is connected, and, outside that, a roughness marking
the insertion of the posterior costo-transverse ligament. The whole
extent beyond the tubercle constitutes the body. It is laterally com-
pressed, and broader from above downwards towards the anterior
extremity. Outside the tubercle, between it and the most convex part
of the body, is a rough line, which corresponds to the outer border of
the erector spinee muscle, and marks the angle, so-called because at this
point the rib takes a more sudden curve, its direction being now for-
wards and outwards. The inferior border presents on its inner aspect
ithe subcostal groove, in which lie the intercostal vessels and nerve, and
which is best marked opposite the angle, and disappears in front. The
‘anterior extremity is hollowed at its tip into an oval pit, in which the
costal cartilage is implanted.

Inclination and Curves.—There is a general inclination of the ribs
downwards from the head to the anterior extremity, the slope being
greatest between the head and angle. The curve of the ribs is more
marked towards the back part than in front, especially near the angle.
Besides the main curves now mentioned the rib is somewhat twisted on
itself, so that while its surfaces are vertical behind, they are placed
somewhat obliquely in front.

Special characters of certain ribs.—The ribs increase in
length from the first to the eighth, and decrease from the ninth to the
twelfth, so that the last is little longer, often even shorter, than the
first. The first rib is the broadest, and after it the middle ones ; the
twelfth is the narrowest. The distance of the angle from the tubercle
increases gradually from the second to the eleventh ; in the first the
angle coincides with the tubercle, in the last it is effaced.

The first rib is not twisted, and is so placed that its superficial and
deep surfaces look respectively nearly upwards and downwards. The
head is small, and presents a single articular surface. The neck is round
and slender. It articulates with the body and transverse process of the
first dorsal vertebra alone. On the superior surface are two very slight
smooth depressions with an intervening rough mark, and a considerable
rough surface behind. The rough surface marks the attachment of the
scalenus medius muscle, the posterior depression the position of the
subclavian artery, the anterior depression the subclavian vein ; and the
intervening slight elevation, frequently terminating in a sharp spine on
the inner edge—the scalene tubercle—indicates the attachment of the
scalenus anticus muscle.

The second rib, longer than the first, presents externally a prominent
roughness which marks the attachment of the serratus magnus.

The eleventh and twelfth ribs have no groove on the inferior border,
no articular facet on the tubercle, and only a single articulating surface
on the head. The mark of the angle is scarcely perceptible on the
eleventh, and is absent from the twelfth.

Varieties.—The number of the ribs is sometimes increased to thirteen on one
or both sides. The supernumerary rib is most frequently very short, and is

THE THORAX AS A WHOLE. 29)

usually formed in connection with the transverse process of fhe first lumbar
vertebra, or occasionally with the seventh cervical: in the latter case the addi-
tional rib has usually a double attachment, viz., to the body and transverse pro-
cess of the vertebra outside a vertebrarterial foramen (see fig. 21, 4, 7, v, and.
8, co.

The costal cartilages unite the ribs to the sternum. Their
breadth diminishes gradually from the first to the last, whilst their
length increases as far as the seventh, after which they become gradually
shorter. Their line of direction varies considerably. The first
descends a little, the second is horizontal, and all the rest, except the
last two, ascend more and more from the rib towards the sternum as
they are situated lower down. The external or costal extremity, convex
and uneven, is implanted into and united with the end of the corre-
sponding rib. ‘The internal extremities of the upper seven (except the
first) are smaller than the external, somewhat pointed, and fit into
the corresponding angular surfaces on the side of the sternum, with
which they are articulated in synovial cavities. Each of the cartilages
of the first three asternal ribs becomes slender towards its extremity,
and is attached to the lower border of that which is next above it. The
last two are pointed and unattached.

The first cartilage, which is directly united to the sternum without
articular cavity, usually becomes more or less ossified in the adult male ;
and the others likewise exhibit a considerable tendency to ossify in
advanced life. This tendency is not so great in the female, in whom
costal respiration is generally more extended than in the male.

THE THORAX AS A WHOLE.

The bony thorax is of a somewhat conical shape, with convex walls.

Fig. 24.—Front view oF THE THORAX, Fig. 24,
SHOWING THE StERNUM CosTAL CARrI-
LAGES, Rigs, AND DorsaL VERTEBRS. }

1, the manubrium, or first piece of the
sternum ; 2, is close to the place of union
of the first costal cartilage; 3, the clavicular
notch ; 4, the middle of the body of the
sternum ; 5, the ensiform process ; 6, the
groove on the lower border of the ribs ; 7,
the vertebral end of the ribs; 8, the neck;
9, tubercle ; 10, costal cartilage ; 12, the
first rib ; 13, its tuberosity ; 14, the first
dorsal vertebra; 15, the eleventh ; 16, the
twelfth rib.

Its upper opening is contracted,
and bounded by the first dorsal
vertebra, the first pair of ribs, and
the manubrium of the sternum. Its
inferior margin slopes downwards
and backwards on each side from
the ensiform cartilage to the
twelfth rib. Its longitudinal axis
is directed upwards and somewhat backwards. _Its transverse diameter,
at its widest part, greatly exceeds that from before backwards. The latter
is shortened in the middle line by the projection of the vertebral column,

30 BONES OF THE THORAX.

but on each side of the column a considerable extension of the cavity is
produced by the backward direction of the posterior parts of the ribs,
and thus the weight of the body is thrown further back and is more
equally distributed round the vertebral column. At the same time
a broad furrow is produced between the spines of the vertebra and
the angles of the ribs, in which are placed the erectores spine muscles.

The intercostal spaces are eleven in number, somewhat wider above
than below, and varying in width with the elevation or depression of
the ribs.

OSSIFICATION OF THE RIBS AND STERNUM.

* The ossification of the ribs begins in cartilage posteriorly about the eighth
week, and extends rapidly forwards, so as to reach the permanent cartilage about

Fig. 25. Fig. 25. —OnzE oF THE
Mripp.eE Ries about
EIGHTEEN OR TWEN-
TY YEARS OF AGE
(R. Quary.)

1, the principal
piece or body; 2, the
epiphysis of the head ;
3, that of the tuber-
cle.

the fourth month.
Subperiosteal ossi-
fication contributes
largely to their sub-
sequent growth. After puberty the centres of two small epiphyses appear in
the cartilage of the head and tubercle. These become united with the main bone
before the twenty-fifth year.

The ossification of the sternum begins about the sixch month, and usually by

Fig. 26.

Fig. 26.—OssrFIcaTIon oF THE Sternum. (R. Quart.)

A, the cartilaginous sternum before the middle of foetal life.

B, the sternum of a child at birth. 1, 2, 3, & 4, mark the commencing ossific nuclei
for the manubrium and three upper pieces of the body.

C, the sternum soon after puberty, showing cartilage between the manubrium and

BONES OF THE HEAD.—OCCIPITAL. 31

body, and imperfect union of the first, second, and third pieces of the body, while the
third and fourth are united.

D, example of a sternum at birth with an unusual number of ossifie centres, six
in the manubrium, 1’, which is very uncommon; two pairs in the lower pieces of
the body 3’ & 4’, which is not unusual; 2, the single centre of the first piece of the
body.

i example of the perforated sternum, which probably depends upon the imperfect
union of the pairs of ossific nuclei shown in D in the lower part of the body ; this figure
also shows two episternal bones or granules, * *. C, and E, are reduced below the size of

nature.

a single centre in the presternum. ~ The next centre appears at the seventh
month in the upper segment of the mesosternum, and ossification follows in the
next two segments shortly before birth. In the lower segments, ossification
begins in the first year or later, and in the metasternum not before the sixth
year, and often much later. In the presternum occasionally two centres of ossi-
fication appear, one above the other. In the upper segment of the mesosternum
the centre is most commonly single, but in each of the following segments there
are frequently two placed one on each side of the middle line. The lower seg-
ments of the mesosternum unite together after puberty, but the upper one often
remains separate till after the twenty-fifth year. The metasternum is united to
the mesosternum in middle life, the presternum in more advanced life. The
bony parts formed from the lateral centres of the lower segments of the meso-
sternum, as well as of the metasternum, not unfrequently remain separate for a
considerable time, and occasionally, by defect of ossification or non-union across
the middle line, have a permanent median aperture in the bone—the so-called
foramen sternale. The metasternum is sometimes bifid, and in rare cases the
mesosternum has been found divided to a greater or less extent from below
upwards, constituting the malformation of fissura sterni, and connected in some
instances with ectopia cordis. (See the case of E, Groux, described by Allen
Thomson in the Glasgow Med. Journal, 1858.)

III—THE BONES OF THE HEAD.

The skull, comprising the bones of the head, is of a spheroidal figure,
compressed on the sides, broader behind than before, and supported
on the vertebral column. -All its bones, with the exception of the
lower jaw, are almost immovably united together by lines and narrow
surfaces, more or less uneven, termed swtwes. The skull is divided by
anatomists into two parts, the cranium and the face. The cranium
protects the brain ; the face surrounds the mouth and nasal passages,
and completes with the cranium the orbits or cavities for the eyes. The
cranium is composed of eight bones, viz.: the occipital, two parietal, the
frontal, two temporal, the sphenoid, and the ethmoiw. The face is com-
posed of fourteen bones, of which twelve are in pairs, viz.: the superior
maxillary, malar, nasal, palate, lachrymal, and inferior turbinated bones ;
and two single, viz., the vomer, and the inferior mazilla. There is also
suspended by ligaments from the under surface of the cranium, the
hyoid bone, which may be classed with the bones of the head.

THE OCCIPITAL BONE

The occipital bone is situated at the lower and back part of the
cranium. In general form it is rhomboidal, and through its lower and
anterior part passes a large oval foramen, forming the communication
between the cranium and spinal canal. The portion of the bone behind
the foramen is tabular, the narrower part in front forms a thick mass
named basilar process, and the parts on the sides of the foramen, bearing

32 BONES OF THE HEAD.

the condyles or articulating processes by which the head is supported
on the first vertebra, are the condylar portions.

Fig. 27.—Occrpiran Bonn
FROM BELOW AND BEHIND,
SHOWING THE EXTERNAL
Surrace. (A. 7.) 3

1, basilar process; 2, con-
dyloid portion, the probe
marks the anterior condylar
foramen ; 3, jugular or trans-
verse process ; 4, external or
lateral angle; 5, superior
angle ; 6, superior curved line ;
7, external or posterior occi-
pital protuberance ; 7, 8, ex-
ternal occipital crest ; 9, in-
ferior curved line ; 10, groove
and ridge connected with the
attachment of the superior
oblique muscle ; 11, fora-
men magnum; 12, articular
condyle ; immediately above
it the posterior condylar fora-
men.

The two superior bor-
ders are deeply serrated,
and are articulated with
the parietal bones in the lamodoidal suture. By its two inferior

Fig, 28. Fig. 28. —Occrertan Bone
FROM BEFORE, SHOWING THE
Internat Surrace. (A.T.) $

1, basilar process sawn
through at the place of union
with the sphenoid bone; 2,
condylar portion ; 3, jugular
or transverse process; x, be-
tween 2 & 3, the sigmoid
groove of the lateral sinus and
the jugular notch ; 4, external
or lateral angle ; 5, superior
angle; 1 to 3, the edge of
articulation with the petrous
bone ; 3 to 4, with the mas-
toid bone; 4 to 5 with the
parietal bone; 11, foramen
magnum ; 13, internal occipi-
tal protuberance and groove of
the torcular Herophili ; 14, in-
ferior spine ; 15, groove of the
lateral sinus; from 5 to 13,
groove of the superior longi-
tudinal sinus; 16, cerebral
fossa ; 17, cerebellar fossa.

j iil fh . } Ni

ye NK : ‘ ==,

borders, which are un-
even but not deeply ser-
rated, it articulates with the mastoid and petrous portions of the

OCCIPITAL BONE. 83

vemporal bone, while the extremity of its basilar process is united to
the body of the sphenoid, in the young condition by cartilage, but after
‘the age of twenty years by continuous osseous substance. The rhom-
poidal form generally given by the meeting of these borders at the four

angles is not unfrequently somewhat changed to the octagonal, by the
oreater or less projection of subordinate obtuse angles “between the
“apper and lateral, and between the lateral and lower angles.

The tabular portion, or supra-occipital, on its poster ior surface
‘presents a rough prominence, the external occipital protuberance, arching
outwards from which, on each side, is the superior occipital ridge or
curved line, which divides the surface into two parts, the upper, covered
by the hairy scalp, convex and uniform; the lower, uneven, and marked
by the impressions of the muscles of the neck which are attached to it.
‘This lower surface is divided into two lateral portions by a median
ridge called the eaternal occipital crest or spine, and each of these por-
tions is again divided into an upper and a lower surface by the énferior
curved line or ridge, which, after extending some distance outwards, is
met by a ridge and groove passing from before backwards. ‘These sur-
faces mark the attachments of the rectus capitis posticus major and
minor, and of the obliquus capitis superior muscles.

The deep surface of the bone is marked by two smooth ridges which
cross one another, one extending from the upper angle to the great
foramen, and the other transversely from one lateral angle to the other,
and at the point of intersection of these ridges is the infernal occipital
protuberance. Separated by these ridges are four hollows, the superior
and inferior occijntal fossee, which lodge respectively the posterior cere-
bral and the cerebellar lobes. The superior and transverse ridges are
grooved in the course of the longitudinal and lateral venous sinuses
respectively. ‘The wider space where those grooves meet at the internal
occipital protuberance receives the torcular Herophili. The inferior
ridge is single, and is named the internal occipital crest or spme. The
margins of the tabular portion are deeply serrated above the lateral
angles for articulation with the parietal bones ; below that level, they
unite with the mastoid portions of the temporal bones.

The condylar portions or ex-occipitals, bear the articulating
condyles on their lower part, close to the margin of the foramen mag-
num in its anterior half. The condyles are elliptical and converge in
front : their surfaces are convex from behind forwards and from side to
side, and slightly everted. ‘Their inner borders are rough, and receive
the insertion of the odontoid ligaments of the axis. In front, and to
the inside of the condyles, are the anterior condyloid foramina, which
pass forwards and outwards from the interior of the cranium, and
transmit the hypoglossal nerves. Behind the condyles are two pits,
containing usually the posterior condyloid foramina; each of these
gives passage to a vein, but they vary greatly in size and are often
absent on one or both sides. Externally to the condyle, on each side, is
a portion of bone, which is placed over the transverse process of the
atlas, continuous posteriorly with the tabular part, and amteriorly hav-
ing a free excavated margin, the jugular notch, which contributes, with
a notch in the temporal bone, to form the for amen lacerum jugular Oy
its external extremity projects into the angle between the mastoid and
petrous portions of the temporal bone, and is called the jugular eminence.

his process presents inferiorly a rough elevation, which gives attach-
VOL. I. D

34 BONES OF THE HEAD.

ment to the rectus capitis lateralis muscle ; and superiorly a deep groove:
for the lateral sinus before it terminates in the jugular notch.

The basilar process, or basi-occipital, projects forwards and
upwards into the middle of the base of the skull. It increases in thick-
ness and diminishes in breadth towards its extremity. Inferiorly it
cives attachment to the rectus capitis anticus major and minor muscles
and the fibrous band of the pharynx. Its superior surface presents a
smooth depression, the basilar groove, which supports the medulla
oblongata, and close to each lateral margin a slight grooved mark,
which indicates the place of the inferior petrosal sinus.

THEH PARIETAL BONES.

The parietal bones form a considerable part of the roof of the skull.
They have the shape of quadrilateral plates, convex externally, concave
internally. They are a little broader above than below, and the anterior
inferior angle is the most projecting. They articulate with each other
in the middle line, with the frontal bone anteriorly, the occipital
posteriorly, and the temporal and sphenoid below.

On the owter surfare, near its middle, a more marked convexity
exists forming the parietal eminence. Below this is a curved line, ©

Fig. 29.—ExTERNAL SURFACE
OF THE RIGHT PARIETAL.
‘Bong, (As) 3
1, posterior superior angle ;

2, anterior superior angle; 3,

posterior inferior angle; 4,

anterior inferior angle, articu-

lating with the great wing of
the sphenoid bone ; from 1 to

2, superior border in the

sagittal suture ; from 2 to 4,

anterior border in the coronal

suture ; from 1 to 3, posterior
border in the lambdoidal su-
ture ; from 4 to 6, margin of

the squamous suture ; from 3

to 6, the additamentum su-

ture squamose; 5, the tem-
poral or semicircular line above:
which is the parietal eminence ;,

8, parietal foramen.

the parietal part of

+ the temporal ridge,

bounding a_ surface

somewhat flatter than the rest, planum temporale, which forms part of

the temporal fossa. Near the posterior and upper angle, is the small
parietal foramen.

The concave inner surface is marked by shallow depressions corre-
sponding with the convolutions of the brain, and by narrower furrows
branching upwards and backwards from the lower border for the middle
meningeal vessels. The largest of these grooves running from the
anterior inferior angle is sometimes converted into a canal for a short
distance. A slight depression along the imner part of the superior
border, forms with the one of the opposite side, the groove of the

FRONTAL BONE. 35

longitudinal sinus; and a depression at the posterior inferior angle
forms a small part of the groove of the lateral sinus. Near the upper

Fig, 30.—Tur Parrerat Bonr
From THE Instpzg. (A.T.) 3

1, 2, 8, 4, 6, & 8, indicate
the same parts as in the
last figure: between 1 & 2
the half groove of the su-
perior longitudinal sinus ; 3’,
groove of the lateral sinus ;
7, the ramified grooves of the
meningeal vessels ; above x
this groove is converted into a
canal; 9, the irregular pits
for the glandulz Pacchionii.

border there are in most
skulls, but particularly
in those of old persons,
small irregular pits,
fovee glandulares, lodg-
ing the so-named gland-
ule Pacchionii.

Borders. —The ante-
rior, superior, and pos-
terior borders are deeply serrated. The inferior border presents in
the greater part of its extent a sharp or squamous edge, with a slightly
fluted surface directed outwards and overlapped at its anterior extremity
by the great wing of the sphenoid, and behind that by the squamous
part of the temporal bone ; its posterior part is serrated, and articu-
lates with the mastoid portion of the temporal. The anterior border
is slightly overlapped by the frontal bone above, but overlaps the
edge of that bone inferiorly.

THE FRONTAL BONE

The frontal bone, arching upwards and backwards from above the
orbits, forms the fore part of the cranium. It likewise presents
inferiorly two thin horizontal lamine, the orbital plates, which form
the roofs of the orbits and are separated by a mesial excavation, the
incisura ethmoidalis.

The frontal is articulated with twelve bones, viz., posteriorly with
the parietals and sphenoid; outside the orbits with the malars; and
between the orbits, from before backwards, with the nasal, superior
maxillary, lachrymal, and ethmoid bones.

Anterior surface.—The part forming the greatest convexity of the
forehead on each side is called the frontal eminence. It is separated by
a slight depression below from the suwperciliary ridge, a curved elevation
of varying prominence immediately above the margin of the orbit.
Between the superciliary ridges is the surface called giabella. The
margin of the orbit, the orbital arch, is most defined towards its outer
part ; it presents towards its inner third the swpraorbital notch, some-
times converted into a foramen, which transmits the supraorbital nerve
and artery. The extremities of the orbital arch point downwards, and

+

36 BONES OF THE HEAD.

form the iaternal and external angular processes. The internal is but
slightly marked ; the external is strong and projecting, and articulates
with the malar bone. ‘The temporal ridge springs from the external

Fig, 31.

Fig. 31.—Froytan Bone Frou
BEFORE, SHOWING ITs ExrER-
NAL SurRFAcE. (A. T.) 4

1, frontal eminence ; 2, nasal
spine, and above this the ser-
rated surface for articulation of
the nasal and superior maxil-
lary bones ; 3 to 4, supra-orbital
edge—3, internal, and 4, exter-
nal angular process; 5, supra-
orbital notch or foramen; 6,
glabella ; 7, superciliary emin-
ence and ridge; 8, temporal
ridge, and behind this a part of
the temporal fossa.

process, and arches up-
wards and backwards to
be continued on the
parietal bone : it separ-
ates the temporal from
the frontal part of the
outer surface of the bone.
Inferior surface.—The orbital surfaces are somewhat triangular,
their internal margins being parallel, while the external are directed
backwards and inwards. Close to the external angular process is the
Jossa lachrymalis, which lodges the lachrymal gland ; and close to the
internal angular process is a small impression where the pulley of the
trochlearis muscle is attached. Between the orbits in front is thé
serrated surface which articulates with the superior maxillary and nasal
bones, and in the middle line a sharp process of variable length, the
nasal spine, descends between the latter bones and the central plate of
the ethmoid. Between the incisura ethmoidalis and the inner margin
of the orbit is an irregular surface occupied with depressions forming
the roofs of cells in the ethmoid bone. ‘Traversing this surface are two
grooves, which complete, with the ethmoid, the anterior and posterior
eternal orbital foramina. The anterior groove transmits the nasal twig
of the ophthalmic nerve and the anterior ethmoidal vessels ; the other,
the posterior ethmoidal vessels. Further forward, on each side of the
nasal spine, is the larger opening of the frontal sinus, a cavity which
extends within the bone for a variable distance behind the superciliary
ridges. Outside and behind the orbital surface, there is a large serrated
triangular area which articulates with the great wing of the sphenoid.
Cerebral surface.——This surface forms a large concavity, except over
the roofs of the orbits, which are slightly convex. Upon it are seen
the impressions of the cerebral convolutions, which, with the inter-
vening ridges, are strongly marked over the orbits. A groove, the
sulcus frontalis, lodging the longitudinal sinus, descends from the
middle of the upper margin of the bone, and is succeeded by the erista
frontalis, aridge which runs down to the lower margin. A small fora-
men, usually formed in part by the central plate of the ethmoid, is

TEMPORAL BONE. 37

.

situated at its base; it is known as the foramen cecum, and transmits a
minute vein from the nasal fosse. ‘The upper and greater part of the

Fig. 32.—Tuu Frontan Bonn
FROM BEHIND AND BELOW,
SHOWING THE INTERNAL CERE-
BRAL SURFACE AND THE Rooy
or THe Ornsits. (A. 1.) $

2, 4, and 5, as in the preceding
figure ; 9, internal or cerebral
surface, slightly marked by cere-
bral convolutions and glandular
pits ; 10, groove of the superior
longitudinal sinus, ending below
in, 11, the internal frontal crest,
which leads down to, 13, the
foramen cecum ; 12, the orbital
plate, the number is placed in
the depression for the lachrymal
gland; 14, the opening of the
frontal smus; 15, placed on
the roof of the orbit internally,
is near the opening of the an-
terior ethmoidal or internal
orbital foramen.

edge encompassing the
cerebral surface of the
bone is deeply serrated,
and articulates with the parietal bones in the coronal suture; the lower
transverse part is thin and uneven, and articulates with the greater and
lesser wings of the sphenoid in the transverse suture. The adult
frontal bone is sometimes divided into two parts by a median suture,
the frontal suture which may be regarded as the persistence of the
original foetal condition.

THE TEMPORAL BONE.

The temporal bone (os temporis) takes part in the construction of
the side and base of the skull, and contains in its interior the organ of
hearing. It is usually described in three parts, viz., an expanded
anterior and superior part, the sgwamous portion with the zygomatic
process, a thicker posterior portion, the mastoid, and below and
between these the pefrous portion, a three-sided pyramid, exhibiting
at its base externally the aperture of the ear, and projecting forwards
and inwards into the base of the skull. With these is combined in the
adult the styloid process or bone.

It articulates posteriorly and internally with the occipital bone, supe-
riorly with the parietal, anteriorly with the sphenoid, by the zygomatic
process with the malar, and by the glenoid cavity with the inferior
maxillary bone.

The squamous portion, or squamo-zygomatic, extends forwards
and upwards from its connection with the other portions, and presents
superiorly an arched border which describes about two-thirds of a circle.

The inner surface is marked by cerebral impressions, and by meningeal
erooves. At its upper border, the outer table is prolonged considerably
beyond the inner, forming a thin scale with the fluted surface looking

38 BONES OF THE HEAD.

inwards and overlapping the corresponding bevelled edge of the parietal
bone. But in front the border is thicker, looks directly forwards, and
is serrated for articulation with the great wing of the sphenoid bone.

Fig. 33. Fig. 33.—Rieur Trempo-
RAL BoNE FROM THE
outsipy, (A. T.) 2%

1, the external surface
of the squamous part ; 2,
the zygoma ; 3, the mas-
toid part ; 3 x, the mas-
toid process ; 4, the arti-
cular part of the glenoid
fossa; 5, the articular
eminence at the root of the
zygoma, and above it the
tubercle; 6, fissure of
Glaser ; 7, the tympanic
plate forming the posterior
non-articular part of the
glenoid fossa, terminating
behind in the vaginal pro-
cess ; 8, the meatus audi-
torius externus; 9, the
auditory process ; 10, the
styloid process ; 13 x, the
mastoid foramen.

The outer surface is in its greatest extent vertical, with a slight con-
vexity, and forms part of the temporal fossa. From its lowest part a
long process, the zygoma, takes origin.

34, Fig. 34.—Tur Ricut Trem-
PORAL BONE FROM THE
INNER SIDE. (A. T.) 3

The indications where
marked are the same as in
the preceding figure. 11, the
inner or cerebral surface of
the squamous portion ; 11x,
the squamous edge, 12, inner
surface of the mastoid por-
tion ; 13, the sigmoid groove
of the lateral sinus—the
figure is placed at its upper
part, and close to the mastoid
foramen ; 14, the apex of the
petrous bone ; 15, the meatus
auditorius internus; 16, the
scale of bone covering the
aqueduct of the vestibule;
17, is above the aqueduct of
the cochlea ; 18, the superior
petrosal groove; 19, the
eminence of the superior
semicircular canal; 20, the
hiatus Fallopii.

The zygomd, or zygomatic process, is connected with the lower and
cuter part of the squamous portion, and is of considerable breadth at
its base, which projects outwards. It then becomes narrower, and is

TEMPORAL BONE. 39

‘twisted on itself so as to present an outer and inner surface, and a sharp
upper and lower border. The superior margin is thinner, and prolonged
further forward than the inferior. The bevelled extremity is serrated,
and articulates with the malar bone. At its base the zygomatic process
presents two roots. The anterior root is a broad convex ridge, directed
inwards. The posterior root passes backwards, and is divided into two
parts, of which one turns inwards in front of the meatus externus, while
the other, gradually subsiding, is continued backwards over that
opening, and marks behind it the line of union of the squamous and
mastoid portions of the bone. At the point of division of the two
roots is a slight ¢udercle, which gives attachment to the external lateral
ligament of the lower jaw. Between the two roots is the glenoid fossa,
a depression elongated from without inwards, and which, together with
the cylindrical elevation formed by the anterior root of the zygoma in
front of it, is coated with cartilage, and forms the concavo-convex
surface which articulates with the lower jaw. The fissure of Glaser
separates this articular part of the glenoid fossa from the remain-
ing part behind, which is formed by the tympanic plate of the petrous
division of the temporal bone, and lodges a part of the parotid gland.

The mastoid portion is rough externally for the attachment of
muscles, and is prolonged downwards behind the aperture of the ear
into a nipple-shaped projection—the mastoid process. This process has
on its inner side a deep groove, the digastric fossa, which gives attach-
ment to the digastric muscle; and internal to that is the slight occipital
groove, for the occipital artery. The internal surface of the mastoid
portion is marked by a deep sigmoid depression, which is part of the
groove of the lateral simus. A passage for a vein, of very variable size,
the mastoid foramen, usually pierces the bone near its posterior margin,
and opens into the groove.

Fig. 35.—Tur Rieut Temporat Bonn From
BELow. (A. 7.) 32

The indications where marked are the same
as in the preceding figures. 14, is at the apex
of the petrous bone in the upper opening of the
carotid canal ; 17, aqueduct of the cochlea ;
21, lower rough surface of the petrous bone ;
22, the lower opening of the carotid canal ;
23, the small foramen of Jacobson’s nerve ;
24, the jugular depression, and within it, 25,
the foramen of Arnold’s nerve ; 26, stylo-mas-
toid foramen—the figure is placed in the ante-
rior part of the digastric groove ; 27, groove of
the occipital artery ; 28, place of the anterior
opening of the osseous Eustachian canal.

The petrous portion is named
from its hardness. It contains the
organ of hearing. It forms a three-
sided pyramid, with its base directed
outwards, one surface looking down-
wards, and the other two turned
towards the interior of the skull.

Inferior surface, base, and apex.—aAt the base is the aperture of the

40 BONES OF THE HEAD.

ear. It forms a short canal, the meatus auditorius exrternus, directed:
inwards and a little forwards, narrower in the middle than at its.
extremities, and leading into the cavity of the ¢ympanum, part of
which is seen from the exterior in the macerated bone. It is bounded.
superiorly by the posterior root of the zygoma, and in the remainder of
its circumference chiefly by the external auditory process, a curved
uneven border, to which the cartilage of the ear is attached. This
process is the thickened outer extremity of the tympanic plate, a lamina
one surface of which forms the anterior wall of the external auditory
meatus and the tympanum, while the other looks towards the glenoid
fossa. The upper margin of the tympanic plate is separated from the
glenoid fossa by the fissure of Glaser, while its lower margin descends as
a sharp edge, the eayinal process, which partly surrounds the front of
the styloid process at its base. The sfylowd process is long and tapering, .
and is directed downwards and forwards. It is placed in front of the
digastric fossa,and has immediately behind it the foramen which forms the
outlet of the canalof the facial nerve, named sty/lo-mastoid from its position
between the styloid and mastoid processes. A smooth rounded and.
deep depression, the juyular fossa, lies internal to the styloid process ;.
it isclose to the posterior margin of the bone, and completes with the
jugular notch of the occipital bone the foramen lacerum posterius. In
front and a little to the inside of the jugular fossa is the carotid foramen,.
the inferior extremity of the carotid canal; and internal to the carotid
foramen is a rough surface which gives attachment to the levator palati
muscle, and is continued into the rough inner extremity, or apex of the:
petrous bone. The carotid canal ascends at first perpendicularly, then
turns horizontally forwards and inwards, and emerges at the apex, close
tothe anterior margin. It transmits the internal carotid artery. In the
angle between the petrous and squamous portions of the bone is the
anterior opening of the Hustachian canal.

The posterior surface looks backwards and inwards, and forms part of”
the posterior fossa in the base of the skull. It presents a large orifice
leading into a short canal which is directed outwards, the meatus audi-
forius internus. This canal is terminated by a plate of bone, the lamina
cribrosa, presenting in the lower part small apertures through which the
divisions of the auditory nerve pass, while in its upper part is the com--
mencement of the canal called aqueduct of Fallopius, which transmits
the facial nerve. This canal takes a somewhat circuitous course:
through the petrous bone, passing outwards and backwards over the
labyrinth of the ear, and then downwards to terminate at the stylo--
mastoid foramen.

The anterior or upper seface looks upwards and forwards, and forms
part of the middle fossa in the base of the skull. A depression near
the apex marks the position of the Gasserian ganglion. A narrow
groove runs obliquely backwards and outwards to a foramen named the
hiatus Fallopi, which leads to the aqueduct of Fallopius, and transmits
the large superficial petrosal nerve. Farther back is a rounded emi-
nence, indicating the situation of the superior semicircular canal.

The superior border is grooved for the superior petrosal sinus. The
anterior border is very short, and forms at its junction with the-
squamous part an angle in which is situated the orifice of the Husta-
chian canal, the osseous portion of a tube of the same name, which
leads from the pharynx to the tympanum; and above this, partially

SPHENOID BONE. 41

separated from it oy a thin lamella, the processus cochleariformis, is a
small passage which lodges the tensor tympani muscle. The posterior
border articulates with the basilar process of the occipital bone, and
bounds the foramen lacerum posterius.

Small Foramina.—The opening of the aqueductus vestibuli is a narrow fissure,
covered by a depressed scale of bone, ee situated on the posterior surface of the
petrous bone, about three lines behind the internal auditory meatus ; that of the
aqueductus cochlee is a small foramen, beginning in a three-sided wider depression
in the posterior margin, directly below the internal auditory meatus. In the plate
between the jugular fossa and the carotid canal is the foramen by which the
nerve of Jacobson passes to the tympanum. In the ascending part of the carotid
canal is the minute foramen for the tympanic branch of the carotid plexus. In
the jugular fossa are a groove and foramen for the auricular branch of the vagus
nerve; and parallel to the hiatus Fallopii, close to the canal for the tensor
tympani muscle, are a groove and foramen for the small superficial petrosal
nerve.

The description of the small bones of the ear with the tympanum and internal
ear, will be found in the chapter on the Organs of the Senses.

THE SPHENOID BONE.

The sphenoid, or wedge-shaped bone, is placed across the base of the
skull, near its middle. It enters into the formation of the cavity of the
cranium, the orbits, and the posterior nares. It is of very irregular
shape, and consists of a central part or body, a pair of lateral expan-

Fig. 36.

Fig. 36.—Tur SpHEnorp BonE FROM ABOVE AND BEHIND. (A.T.) 3%

1, the basilar surface, sawn separate from the occipital bone ; 2, Dorsum sellx, or
inclined surface of the body terminating superiorly in the two posterior clinoid processes ;
3, is placed on the olivary eminence or process, and between it and 2 is the sella turcica,
or pituitary fossa; in front of 3 is the transverse groove of the optic commissure ; 4, the
side of the body with the sigmoid groove of the internal carotid artery and cavernous
sinus ; 5, the lesser wing ; x, the anterior clinoid process ; 6, the ethmoid spine ; 7,
the cerebral surface of the greater wing ; 8, the upper angle of the greater wing, which
articulates with the parietal bone ; 9, the spinous process ; 10, the external, and 11, the
internal pterygoid process ; 11, is placed opposite the hamular process and groove for the
tendon of the tensor palati muscle ; 12, the optic foramen, 13, the sphenoidal fissure or
foramen lacerum orbitale ; 14, the foramen rotundum ; 15, the foramen ovale ; 16, the
omen spinosum ; 17, is placed above the posterior opening of the pterygoid or Vidian

oramen.

42 BONES OF THE HEAD.

sions called the great wings, a pair of smaller horizontal processes in
front, called the small wings, and a pair which project downwards, the
pterygoid processes.

The sphenoid is articulated with all the seven other bones of the
cranium and with five of those of the face, viz., posteriorly with the
occipital and with the petrous portions of the temporals, anteriorly with
the ethmoid, frontal, and malars, laterally with the squamous portion
of the temporals, the parietals and frontals, and inferiorly with the
vomer and palate bones. ,

The body.—Posteriorly the body of the sphenoid is solid, but
anteriorly it is hollowed out into two large cavities, the sphenoidal
sinuses, separated by a thin mesial lamina and opening into the upper
part of the nasal fossa by two rounded apertures. The swperior surface
presents in the middle a deep pit, the pitwtary fossa, or sella turcia,
which lodges the pituitary body. In front of the fossa, separated
from it by a shallow transverse groove, is a narrow portion of bone
on a level with the optic foramina, the olivary process, (tuberculum
sellaee— Henle), on which rests the commissure of the optic nerves ; and in
front of this is a surface on a slightly higher level, continuous with the
superior surfaces of the small wings, and having a slight projection for-
wards of its anterior border, which articulates with the cribriform plate
of the ethmoid, and is called the ethinoidal spine. Behind the pituitary
fossa is a prominent lamella, the dorsum sell, the posterior surface of
which is sloped upwards and forwards in continuation of the basilar
groove of the occipital bone. The angles of this lamella project over
the fossa, and are called the posterior clinoid processes. On each side of
the body the surface descends obliquely to a considerably lower level
than the fossa ; it presents close to the margin of the fossa a super-
ficial curved groove directed from behind forwards, marking the course
of the internal carotid artery. At the bottom of this groove, and in
the angle between the body and the great wing, there projects the small
ridge of bone termed lingula sphenoidalis.

The posterior surface is flat, and is united to the basilar process of the
occipital bone, in early life by cartilage, but m adult age by continuous
bony substance.

The anterior surface presents in the middle line the sphenoidal crest,
a thin projecting edge which extends downwards from the ethmoidal
spine and terminates in the rostrum, a sharp bony prommence projecting
vertically between the anterior and inferior surfaces. The sphenoidal
crest articulates with the central plate of the ethmoid ; the rostrum is
inserted between the ale of the vomer.

The sphenoidal spongy bones (cornua sphenoidalia, bones of Bertin),
form a considerable part of the anterior wall of the body of the sphenoid,
including the foramen of each sinus. These bones have a triangular
form, with the apex directed downwards, and are in the adult usually
incorporated with the sphenoid, but as explained in the account of
their development, they are originally distinct. They are frequently
united by earlier or stronger anchylosis with the ethmoid or palate
bones, so as to come away, at least in part, with either of these in dis-
articulation of the skull, and thus lay open the sphenoidal sinuses. A
small portion of these bones sometimes appears on the inner wall of
the orbit, between the ethmoid, frontal, sphenoid, and palate bones
(Cleland in Trans. of Roy. Soc. for 1862).

SPHENOID BONE. 43

The great wings, al majores, project outwards and upwards from
the sides of the body. The back part of each is placed horizontally,
and occupies the angle between the petrous and squamous portions of
the temporal bone ; “from its pointed extremity it sends downwards a
short and sharp projection, the spinous process. ‘The upper and fore
part is vertical, and three-sided, lying between the cranial cavity, the
orbit, and the temporal fossa. The cerebral surface of the great wing is
concave, and forms part of the middle fossa of the base of the cranium.
The external surface (temporo-zygomatic) is divided by a ridge into an
inferior part, which looks downwards into the zygomatic fossa, and an
elongated superior part, looking outwards, which ‘forms a part of the
temporal fossa. The antervor surface looks forwards and inwards, and
consists of a quadrilateral orbital portion, which forms the back part
of the external wall of the orbit, and of a smaller inferior portion which
overhangs the pterygoid process, looks into the spheno-maxillary fossa,
and is perforated by the foramen rotundum. ‘The external margins
between the cerebral and external surfaces articulate with the temporal
and parietal bones; anteriorly, the margin between the orbital and
external surfaces articulates with the malar bone. The margin below
this forms the upper part of the posterior boundary of the pterygo-
maxillary fissure; internally, the cerebral and orbital surfaces come
into contact at the outer border of the sphenoidal fissure ; and
superiorly, the cerebral, orbital, and external surfaces surround the
triangular area which articulates with the frontal bone.

The small wings, ale minores (wings of Ingr assias), extend nearly
horizontally outwards from the fore part of the superior surface of the
body. The extremity of each is slender and pointed, and comes very
close to, but not into actual contact with, the great wing. The superior
surface forms part of the anterior fossa of the base of the cranium, the
inferior overhangs the sphenoidal fissure and the back of the orbit.

Fig, 37.

Colt

Fig. 37.—Tur SpHenorp Bone FROM BEFORE. (A. T.)

The indications where marked are the same as in the preceding figure. 17, marks the
anterior opening of the Vidian foramen or canal ; 18, the external or temporal surface
of the great wing ; 19, its orbital surface ; 20, the sphenoidal turbinated or spongy bone ;
above 20, the opening into the sphenoidal sinus ; 21, the sphenoidal spine ; 22, the
rostrum, and above 22, the inverted lamin, which fit with the edges of the vomer.

At BONES OF THE HEAD.

The anterior border, thin and serrated, articulates with the orbital
plate of the frontal bone. The posterior border is prominent and free,
and forms the boundary between the anterior and middle cranial fossz,
terminating internally in a smooth rounded knob, the anterior clinoid
process. Below and to the inside of this is the optic foramen.

The pterygoid processes project downwards and slightly forwards,
between the body and the great wings. Lach consists of two plates
united in front and diverging behind, so as to enclose between them
the pterygoid fossa. The external pterygoid plate, broader than: the
internal, lies in a plane extending backwards and outwards ; its outer
surface bounds the zygomatic fossa, and gives attachment to the
external pterygoid muscle. The internal pterygoid muscle arises from
its inner surface. The internal pterygoid plate is longer and narrower
than the external, and is prolonged into the slender hook-like or
hanular process, round which in a groove plays the tendon of the tensor
palati muscle. At its base, the internal plate turns inwards beneath
the body, from which its extremity remains distinct as a slightly raised
edge, which articulates with the everted margin of the vomer; and
externally to this it is marked by a small groove, which contributes
with the palate bone to form the plerygo-palatine canal. The interval
between the lower ends of the pterygoid plates is occupied by the
pyramidal process of the palate bone. At the base of the internal
pterygoid process is a slight depression, distinguished as the navicular
fossa, Which gives attachment to the tensor palati muscle.

Fissures and foramina.—Hach lateral half of the bone presents a
fissure, four foramina, and a canal. The sphenoidal fissure is the
obliquely placed elongated interval between the great and the small
wing ; it is closed externally by the frontal bone, so as to form the
foramen lacerum orbitale ; it opens into the orbit, and transmits the
third, fourth, and sixth nerves, the ophthalmic division of the fifth
nerve, and the ophthalmic vein. Above and to the inside of it is the
optic foramen, which is inclined outwards and forwards from the side of
the olivary process, pierces the base of the small wing, and transmits the
optic nerve and the ophthalmic artery. The foramen rotundum is
directed forwards through the great wing, below the sphenoidal fissure ;
it opens immediately below the level of the orbit, and transmits the
superior maxillary division of the fifth nerve. The foramen ovale is
large, placed behind and a little external to the foramen rotundum,
near the posterior margin of the great wing ; it is directed downwards,
and transmits the inferior maxillary division of the fifth nerve. The
foramen spinosum is a small foramen piercing the great wing, near its
posterior angle, and transmits the middle meningeal vessels.

The Vidian or pterygoid canal, passes through the bone horizontally
from before backwards at the base of the internal pterygoid plate ; ib
opens anteriorly into the spheno-maxillary fossa, and posteriorly into
the foramen lacerum medium, and transmits the Vidian nerve and
vessels.

Varieties.—Spicula of bone sometimes connect the anterior clinoid process:
with the pituitary fossa and with the posterior clinoid process. The outer ptery-
goid plate is sometimes connected by a bridge of bone or of ligament with the
spinous process. The foramen ovale and foramen spinosum are frequently in-
complete at the posterior margin of the bone.

ETHMOID BONE. 45

ETHMOID BONE

The ethmoid, or sieve-like bone, projects downwards from between
the orbital plates of the frontal bone, and enters into the formation of
the cranium, the orbits, and the nasal fosse. It is of a cuboid figure.
It is exceedingly light for its size, being composed of very thin plates
of bone forming in part irregular cells. It consists of a central vertical
plate, and of two /ateral masses, the ethmo-turbinals, united at their
superior extremities by the horizontal eribriform lamella.

It articulates with thirteen bones ; the frontal, sphenoid and vomer,
the nasal, lachrymal, superior maxillary, palatal, and inferior turbinated
bones.

The vertical plate lies in the mesial plane, and forms the upper
part of the septum of the nose. Its superior margin appears in the
cranial cavity, above the cribriform lamella, in the form of a ridge

Fig. 38.—Tus Erumoip Bonn. (A. 1.) 3 Fig. 38.

A, from the right side. 1, crista galli; 2,
vertical plate ; 3, cribriform plate and foramina ;
4, orbital plate or os planum ; 5, 5, the uncinate
process ; 6, the superior, and 7, the inferior
turbinated bone ; 8, the anterior, and 9, the
posterior ethmoidal groove or foramen.

B, the ethmoid bone from behind. The in-
dications where marked are the same as in A.
10, the lateral or cellular part of the bone ; 11,
its posterior surface of union with the sphenoidal
turbinated and palate bones.

which rises anteriorly into a_ thick
process, the crista galli, to which the
falx cerebri is attached. The an-
terior margin of the crista galli is
vertical and broad, usually present-
ing a groove, which completes the
foramen cecum of the frontal bone.
Below the level of the cribriform
lamella, the anterior margin of the
vertical plate articulates with the
nasal spine of the frontal and occasionally with the nasal bones. The
inferior margin articulates in front, and sometimes even in its whole
extent, with the septal cartilage of the nose ; and in its posterior half, in
the adult, it is more or less completely joined by osseous union on one
or both sides to the two plates or ale of the vomer. The posterior
margin is very thin, and is united to the crest of the sphenoid.
This plate presents superiorly a number of grooves and minute
canals leading from the foramina of the cribriform lamella, for the
transmission of the olfactory nerves.

The lateral masses enclose a number of spaces of irregular form,
arranged in two sets, the anterior and posterior ethmoidal celis,
which in the recent state are lined with prolongations of the mucous
membrane of the nose. On the ezternal aspect of each lateral mass
is a thin, smooth lamina, of a quadrilateral form, the orbital plate or
os planum, which closes in the ethmoidal cells, and forms a consider-

46 BONES OF THE HEAD.

able part of the inner wall of the orbit. ‘The crbital plate articulates
in front with the lachrymal, behind with the sphenoid, above
with the frontal, and below with the orbital surfaces of the superior
maxillary and palate bones. In front of the orbital plate the lateral
mass extends forwards, under cover of the lachrymal bone ; and from
this part descends the wncinate process, a long thin lamella which curves
downwards, outwards and backwards, forming part of the inner wall of
the maxillary sinus, and articulating at its extremity with the inferior
turbinated bone.

The internal aspect of each lateral mass forms part of the external
wall of the nasal fossa, and consists of a thin, uneven plate, connected
above with the cribriform lamella, and exhibiting a number of canals
and grooves for branches of the olfactory nerve. It is divided at its
back part by a channel, directed forwards and upwards from its poste-
rior margin to about its middle. This is called the saperior meatus of
the nose, and communicates with the posterior ethmoidal cells. The
short margin which overhangs this channel constitutes the superior tur-
binated process or spongy bone. Below this is a slightly folded margin
of greater extent, free in front and behind, the inferior turbinated pro-
cess or middle spongy bone, which overhangs the middle meatus of the
nose. From the front of the middle meatus a passage, the enfundibulum,
is prolonged upwards and forwards through the anterior ethmoidal
cells, into the frontal sinus.

In the separate ethmoid bone the cells are open posteriorly and
superiorly, but when the bone is in connection with the rest of the
cranium these cells are closed, above by the frontal bone, and behind
by the sphenoidal spongy bones. In the superior margin are two.
grooves, which complete with the frontal bone the internal orbital
foramina.

The cribriform lamella corresponds in size to the incisura ethmoi-
dalis of the frontal bone which it occupies. At the sides of the crista
it is depressed into two grooves which lodge the olfactory bulbs ; and
it is pierced by numerous foramina, for transmission of the filaments
of. the olfactory nerves. he foramina which le along the middle of
each groove, are simple perforations ; the internal and external sets are
longer, and are the orifices of small canals which subdivide as they
descend on the vertical plate and lateral masses. At the anterior
extremity is a small fissure at each side of the crista galli, close to its.
base, and externally to this a foramen, connected usually by a slight
groove with the anterior internal orbital foramen, which transmits the
nasal branch of the ophthalmic nerve.

THE SUPERIOR MAXILLARY BONE.

The upper jaw, mazilla superior, is one of the principal bones of the
face ; it supports all the teeth of the upper range, and takes part in the
formation of the hard palate, the floor of the orbit, and the floor and
lateral wall of the nasal cavity. It presents inferiorly a thick ridge,
the alveolar process, containing the sockets or alveoli for the roots of
the teeth, and a horizontal palate plate ; externally, a convex surface
corresponding with the anterior and lateral parts of the face; supe-
riorly, an ascending or nasal process and an orbital plate ; and inter-
nally, a nasal surface, opening from which is a large cavity or sinus,

SUPERIOR MAXILLARY BONE. 47

hollowed out beneath the orbital plate in the body of the bone. The
superior maxillary bone articulates with its fellow, with the nasal,
frontal, lachrymal, ethmoid, palate, malar, vomer, and inferior turbi-
nated bones, and with the nasal cartilages.

The alveolar border or process, thick and arched, is hollowed out into
sockets or alveoli, corresponding in number, form, and depth to the roots.
of the teeth, which are fixed in them.

The palate plate, along with that of the opposite side, forms about
three-fourths of the hard palate. Its superior surface is smooth and
concave from side to side ; its inferior surface is vaulted and rough,
and is marked laterally with grooves for nerves and vessels, which
reach the palate through the posterior palatine canal. Its posterior
extremity falls short of that of the alveolar arch and body of the bone,
and articulates with the horizontal process of the palate bone, which
completes the hard palate. The mesial border rises into a serrated
vertical ridge, which, with its fellow, constitutes in front the nasal

Fig. 39.—Suprerton Maxinnary Bonn or THE
Rieut Sipn. (A. 7.) 4

A, from the outside ; B, from the inside.

1 to 2, alveolar process or arch—1 at the
middle incisor tooth, 2 marks the tuberosity,
and above it, in A, the posterior dental foramina ;
3, the nasal or ascending process; 4, malar
tuberosity or process ; 5, orbital plate or process ;
6, placed in front of the nasal notch marks the
nasal crest terminating in the nasal spine ; 7, the
incisor or myrtiform fossa; 8, is in front of the
canine fossa ; 9, the infra-orbital foramen, and
below 5, the infra-orbital groove and canal ; 10,
groove of the nasal or lachrymal duct ; 11, antrum
maxillare, or maxillary sinus; 12, marks the
oblique ridge for the attachment of the inferior
turbinated bone ; 13, is placed above the palate
plate ; from 13 to 6, the vomeric and nasal crest ;
from 13 to 14, the anterior palatine foramen ; 15,
placed on the surface of articulation of the body
with the palate bone, points to the groove of the
palato-maxillary canal. These figures also exhibit
a full set of the upper teeth of one side as they
occur in middle life.

A

ise)

crest—a grooved elevation which sup-
ports the extremity of the vomer and
the septal cartilage, and is prolonged
forwards into the nasal spine. This
ridge is interrupted at its anterior
part by a canal, the iecisor foramen,
which is completed on its mesial side by a slender lamina passing
from the anterior to the posterior border. Each incisor foramen
widens out below into a larger hollow, which when placed in appo-
sition with that of the opposite side, completes a mesial aperture,
the anterior palatine foramen. Viewed from below, this aperture may
be seen to be divided into four smaller foramina, two of which, placed
laterally, are the incisor foramina, called also foramina of Stenson, while
the other two, placed in the middle line, one before, the other behind,

AS BONES OF THE HEAD.

are distinguished as the foramina of Scarpa. The whole communi-
cation between the nose and the palate may be designated collectively
as the anterior palatine canal.

Fig. 40.—Front Part or tHp PALATR AND
AtveouarR ArcH oF AN ApuULT. 3

Showing the lower opening of the anterior palatine
or incisor foramen. 1, 2, are placed on the palate plates
of the two superior maxillary bones ; 4, anterior pa-
latine foramen, in which is seen a partial division into
four openings—the two lateral, with lines pointing to
them from 1 and 2, are the incisor foramina (foramina
of Stenson) ; the anterior and posterior, indicated by
3 and 4, are the naso-palatine, or foramina of Scarpa.

The terms incisor foramen and anterior palatine canal are often used convertibly
and vaguely to express what has been above defined as the anterior palatine canal, or
its inferior opening. According to the definitions here given, incisor foramen has
the same meaning in human as in comparative anatomy, while anterior palatine
canal is restricted to an appearance which presents itself only in man and a few
animals. The lamina passing backwards from before each incisor foramen corre-
sponds to the mesial palatine process of the intermaxillary bone in other animals,
eg. the carnivora : while the incisor foramina are those which are seen largely
developed in those animals, and are the remains of a primitive communication
between the nose and mouth. The foramina of Scarpa le in the suture between
the laminz referred to. They transmit the naso-palatine nerves; the nerve of
the right side occupying, according to Scarpa, the posterior one, which is usually
largest, and that of the left side, the anterior: but they are very inconstant.
(Scarpa, Annot. Anatom., lib. 11. cap. 5.)

The external surface is divided into an anterior and a posterior part
by the malar process, 2 prominence situated above the first molar tooth,
and presenting a large triangular roughness for articulation with the
malar bone. The anterior portion is deeply notched at its internal
margin for the opening of the anterior nares. It is marked by a pro-
minence corresponding to the position of the fang of the canine tooth ;
and internal to this is a slight depression, the ccisor or myrtiform fossa ;
while between it and the malar process is the deeper canie fossa, in
which arise the levator anguli oris and compressor nasi muscles,
Above the canine fossa, immediately below the margin of the orbit, is
the infra-orbital foramen, which transmits the superior maxillary nerve.
The posterior portion looks partly into the zygomatic, partly into the
pterygo-maxillary fossa. It exhibits a rough convexity, the faberosity,
projecting backwards, and is perforated by a number of foramina
transmitting the superior dental nerves and arteries.

The nasal process projects upwards from the anterior and internal
part of the bone. Its internal surface, towards its summit, is rough
for articulation with the lateral mass of the ethmoid; its anterior
border is rough for articulation with the nasal bone, and its summit
serrated for articulation with the frontal. Posteriorly it articulates by
a linear edge with the lachrymal bone; and external to this it presents
a well-marked groove for the lachrymal sac, the lachrymal groove, which
is continued downwards on the inner surface of the bone, between this
process and the orbital plate, and with the lachrymal and inferior
turbinated bones forms the nasal canal.

The nasal surface presents an oblique rough line or ridge beneath the

PALATE BONE. 49

ascending process, for articulation with the inferior turbinated bone,
and behind that process the lachrymal groove. Behind the lachrymal
groove is the large opening into the sinus; behind the sinus the sur-
face is rough for articulation with the palate-bone ; and traversing the
lower part of this roughness is a smooth groove, passing downwards
and forwards from the posterior margin, and completing with the
palate bone the posterior palatine or palato-maxillary canal.

The orbital surface extends from the margin of the orbit to the
spheno-maxillary fissure, and is bounded externally by the surface for
the malar bone, and internally by the lachrymal groove and a rough
edge which articulates with the lachrymal, ethmoid, and palate bones.
A groove commences in its posterior border, and leads forwards into a.
complete canal, the wfraorbital, which opens anteriorly at the infra-
orbital foramen.

The mazillary sinus, or antrum of Highmore is a large cavity lying
above the molar teeth and below the orbital plate, lined in the fresh
state by mucous membrane, and communicating with the middle
meatus of the nose. Its orifice is considerably diminished by con-
tiguous bones, viz., by the uncinate process of the ethmoid, the inferior
turbinated bone, and the palate bone.

THE PALATE BONE.

The palate bone forms the back part of the hard palate, and the
lateral wall of the nose between the superior maxillary bone and
the internal pterygoid process. It consists of a horizontal and a
vertical plate united at a right angle, and of three processes, viz., the

Fig. 41.—Tue Panate Bonz or THE Rieut Sipe. Fig. 41.
(Ax TE) le

A, from the outside and behind ; B, from the inside.

1, the upper surface of the palatine plate; 2, its

posterior curved border or palatine arch ; 3, posterior
nasal or palatine spine; 4, the rough surface of adjacent
articulation rising superiorly into the vomeric crest in
A ; 5, 5, the nasal process ; 6, the ridge or shelf support-
ing the inferior turbinated bone; 7, the sphenoidal
process ; 8, in B, the orbital process, showing a cellular
cavity; 8, in A, its orbital surface; 9, the spheno-
palatine notch ; 10, 11, 12, the pyramidal process—10,
rough surface of union with the external pterygoid plate,
11, with the internal plate, and 12, the inter-pterygoid
smooth surface ; 13, 13, groove of the palato-maxillary or
posterior palatine canal.

pyramidal process, extending outwards and
backwards from the junction of the horizontal
and vertical plates, and the orbital and sphe-
noidal processes, surmounting the vertical
plate.

The palate bone articulates with its fellow,
and with the superior maxillary, ethmoid,
sphenoid, yomer, and inferior turbinated bone.

The horizontal or palate plate presents pos-

teriorly a thin free border, forming the limit of the hard palate, and
MOT. J; E

50 BONES OF THE HEAD.

giving attachment to the soft palate or velum : anteriorly it articu-
lates with the palate plate of the superior maxillary bone, and inter-
nally by a thick serrated border with its fellow of the opposite side,
forming with it a ridge or crest for articulation with the vomer,
continuous with that of the superior maxillaries; externally, at its
junction with the vertical plate, it is grooved by the extremity of the
posterior palatine canal. Its superior surface is smooth, and forms the
back part of the floor of the nasal cavity; its inferior surface is rough,
and is marked near its posterior border by a transverse ridge which
gives attachment to the tendinous fibres of the tensor palati muscle.

The vertical plate is very thin. Its internal or nasal surface is divided
_into two parts, corresponding to the middle and inferior meatus of the
nose, by a nearly horizontal ridge which articulates with the inferior
turbinated bone. The external surface is smooth, and at its upper part
forms the internal wall of the spheno-maxillary fossa, while the lower
part is hollowed into a deep groove, completing with the superior maxil-
lary the posterior palatine canal, which transmits the large descending
palatine nerve and vessels. In front of this canal the external surface is
in contact with the internal surface of the maxillary bone and the inner
side of the antrum ; behind the canal it articulates inferiorly with the
hinder border of the maxilla, superiorly with the inner surface of the
pterygoid process.

The pyramidal process or tuberosity fits into the cleft between the
pterygoid plates. It presents posteriorly a triangular surface which is
smooth and grooved, and completes the pterygoid fossa ; on its sides it
is rough for articulation with the borders of the ‘pterygoid plates.
Inferiorly, close to its connection with the horizontal plate, are two
small foramina, the posterior and external small palatine foramina, the
extremities of two minute canals which transmit the smaller palatine
nerves ; the external one is the smaller and is inconstant.

The orbital process surmounts the anterior margin of the vertical plate.
It is somewhat pyramidal in shape, and has five surfaces, two of which,
the superior and external, are free, and the rest articulated. The
superior surface forms the posterior angle of the floor of the orbit ; the
external looks into the spheno-maxillary fossa, the anterior articulates
with the maxillary, the internal with the ethmoid, and the posterior,
which is small and only exists towards the extremity of the process,
articulates with the sphenoidal spongy bone.

The orbital surface is frequently found enlarged from the union with
the palate bone of a portion of bone ossifying from a separate centre,
usually united with the ethmoid or sphenoid, and already described with
the sphenoidal spongy bone (p. 40).

The sphenoidal process curves upwards, inwards, and backwards from
the posterior part of the vertical plate. Its superior or external surface
is in contact with the sphenoidal spongy bone and the base of the
internal pterygoid plate, and is grooved for the completion of the
pterygo-palatine canal; its internal or under surface looks to the
posterior nares ; and at its base a third surface looks forwards and out-
wards into the spheno-maxillary fossa. Its inner extremity is in con-
tact with the wing of the vomer.

The spheno-palatine foramen is formed in greatest part by the deep
notch between the orbital and sphenoidal processes, and is completed
above by the sphenoidal spongy bone. It leads from the spheno-

VOMER. MALAR BONE, 51

maxillary fossa into the nasal cavity, and transmits the internal nerves
from Meckel’s ganglion and the nasal branch of the internal maxillary
artery.

THE VOMER.

The vomer is a thin mesial bone, irregularly quadrilateral, and
placed vertically between the nasal fosse. It articulates with the |
sphenoid, ethmoid, palate, and maxillary bones, and with the septal
cartilage of the nose. It usually becomes united by anchylosis, at an
early age, to other bones.

The lower and back part of the vomer forms a thin mesial plate,
while the upper and anterior part consists of two ale, rising on each
side of a mesial groove, in which lies the septal cartilage of the nose.
The ale posteriorly are thick and expanded, and form the bifid
posterior extremity of the bone, which rests beneath the sphenoid. The
superior border of each ala articulates edge to edge with the lamella
projecting inwards at the base of the internal pterygoid plate, and

Fig. 42.—Tur Vomer (A.T.) §
A, from the right side ; B, from above.

1, 1’, the upper everted edges, or alae on each
side of the hollow which receives the rostrum
of the sphenoid ; 2, the anterior or ethmoid
border, grooved to receive the septal cartilage
of the nose, and prolonged at x into a process
which rests upon the nasal crest ; 3, the pos-
terior or free border ; 4, the inferior or maxil-
lary and palatine border.

the sphenoidal process of the palate bone, while the
cavity between the ale receives the rostrum of the
sphenoid ; the anterior border, sloping downwards and
forwards, in contact with the septal cartilage, is free in
the inferior part, and is united superiorly by anchylosis
on one or both sides with the central plate of the ethmoid.
The anterior extremity of the vomer forms a short vertical
plate which fits in behind the nasal crest of the maxil-
laries, and from the upper end of which a process projects
forwards in the groove of the crest, while from its lower
end a point projects downwards between the incisor fora-
mina. The inferior border articulates with the ridge or
crest which rises from the palate plates of the maxillary
and palate bones. The posterior border, thin, smooth, and unattached,
separates the posterior nares.

THE MALAR BONE.

The malar bone forms the most prominent part of the cheek, and
divides the orbit from the temporal fossa. It articulates by a broad
serrated surface near its anterior inferior angle with the malar process
of the superior maxillary bone, by a slender posterior process with the
zygoma, by a superior process with the frontal, and, continuously with
that, by the margin of its deep plate with the great wing of the sphe-
noid bone. Between its sphenoidal and maxillary articulations a small
portion of free margin generally intervenes, which closes the anterior

E2

52 BONES OF THE HEAD.

extremity of the spheno-maxillary fissure. The facial surface is convex,
and pierced by one or more malar foramina, which pass through from

Fig. 43. Fig. 43.—Ricut Mauar Bong. (A. T.)

eo

A, from the outside ; B, from the inside.

1, superior or frontal angle and serrated edge; 2,
posterior or external angle and serrated surface for the
zygoma ; 98, anterior or internal angle; 4, inferior
angle ; from 1 to 2, the temporal border ; from 1 to 3,
the orbital border ; from 1 to 8, edge of articulation
with the frontal and sphenoid bones; at 8, the notch

sually terminating the spheno-maxillary fissure ;
from 2 to 4, the masseteric rough border ; between
8, 3, and 4, the triangular serrated surface for articula-
tion with the superior maxillary bone ; 5, the external
surface ; 6, the deep or posterior surface ; 5 and 6, are
placed near the foramina for the temporo-malar nerves ;
7, the orbital surface, with the orbito-malar foramen.

the orbital surface and transmit a small nerve
and vessels. The orbital surface is concave
from above downwards, and enters into the
formation of the outer wall and floor of the
orbit. The posterior surface is concave from
side to side, and looks into the temporal and zygomatic fosse; it is
also pierced by a small foramen.

THE NASAL BONE,

The nasal bones form the bridge of the nose. They are thick and
narrow above, but gradually become wider and thinner below. The
superior border of each is serrated, and articulates with the frontal
bone; the inferior supports the lateral nasal cartilage; the external
edge articulates with the ascending process of the superior maxillary
bone; and the internal with its fellow, with the nasal spine of the

Fig. 44.—Ricur Nasat Bong. (A. T.) 3

A, from the front ; B, from behind.

1, upper or frontal serrated border ; 2, internal border
for adjacent articulation ; 3, external or superior maxillary
border ; 4, lower free border ; in B, 4 is placed at the
lower end of the groove for the nasal nerve.

frontal bone, and frequently with the perpen-
dicular plate of the ethmoid. The anterior
surface, concave at its upper part, convex in
the rest of its extent, presents a minute vascular

foramen ; the posterior or nasal surface is marked by a groove for the
passage of the nasal nerve.

THE LACHRYMAL BONE,

The lachrymal bone, or os wnguis, is a thin scale of bone placed at
the anterior and inner part of the orbit. It articulates superiorly with
the frontal bone, posteriorly with the orbital plate of the ethmoid;
anteriorly it presents a longitudinal or vertical groove, and articulates
with the ascending process of the superior maxillary bone, completing

INFERIOR TURBINATED AND MAXILLARY BONES, 53

with it the groove for the lachrymal sac; inferiorly it articulates in its
greatest extent with the orbital plate of the superior maxillary bone,
while its anterior grooved part projects downwards, taking part in the

Fig. 45.—Rigut LacuryMau Bonz, FRoM THE outsipE. (A.T.) 2

1, upper or frontal border ; 2, the orbital surface; 3, lachrymal
groove ; 4, the hooked process which meets the inferior turbinated bone.

Fig. 45.

formation of the lachrymal canal, and terminates in a
pointed extremity, hamulus lachrymalis, which fits into
an angle between the superior maxillary and inferior
turbinated bone. The inner surface looks superiorly to
the anterior ethmoidal cells, and inferiorly to the middle meatus of the
nose.

THE INFERIOR TURBINATED BONE.

The inferior turbinated, mazillo-turbinal, or spongy bone, is a slender
lamina, attached by one margin from before backwards along the lateral
wall of the nose, and projecting into the nasal cavity, so as to divide
the middle from the inferior meatus. It is slightly convoluted, its
convexity looking inwards, and its free margin being dependent,
slightly thickened, and rolled upon itself. The attached margin arti-
culates anteriorly with the oblique ridge below the nasal process of the
superior maxillary bone, and ascends abruptly to form the lachrymal
process and complete the lachrymal canal and articulate with the
jachrymal bone; behind this it is folded downwards in the maxillary
process, forming part of the inner wall of the antrum below the

Rig. 46.—Tue Inrerror TurBInateD Bone or Fig. 46.
THE Rieut Sipz. (A. 7.) 2

A, from the outside ; B, from the inside.

1, anterior angle ; 2, posterior angle ; 1, 3, 2,
inferior free border ; 4, internal convex surface ;
5, part of the bone articulating with the uncinate
process of the ethmoid ; 6, portion articulating
with the lachrymal ; 7, the outer concave sur-
face ; 8, the maxillary process or plate deflected
from the upper border, which, by union with the
superior maxillary, forms a part of the inner
wall of the maxillary sinus.

entrance into that cavity; above and
behind this, it presents a small pro-
jection which articulates with the un-
cinate process of the ethmoid, and
posteriorly it is attached to the hori-
zontal ridge on the vertical plate of the palate bone.

This bone is marked by horizontal grooves and canals for vessels and
nerves, but not, as the turbinal parts of the ethmoid are, with vertical
grooves for the olfactory nerve.

THH INFERIOR MAXILLARY BONE.

The inferior maxilla, mandible, or lower jaw, is the thickest and
strongest bone of the face, and moves on the rest of the skull by means

54 BONES OF THE HEAD.

of a pair of articular surfaces or condyles. It has the shape of an
inverted arch bent forwards upon itself, and consists of a middle
larger and horizontal part—the body, and of two rami or ascending
branches.

The body is marked in the middle by a vertical ridge, indicating the
original division of the bone into two lateral parts, and thence named
the symphysis. ‘The superior or alveolar border is hollowed out into
sockets for the teeth. The inferior border, thicker anteriorly than
beneath the ramus, is slightly everted in front, constituting the chin, or
-mentum, & prominence peculiar to the human skull. On the outer
surface, on each side of the symphysis, below the incisor teeth, is a
shallow depression, the dcisor fossa, which gives origin to the levator
menti muscle, and, more externally, the labial or mental foramen, which
transmits the branches of the inferior dental nerve and artery. From
beneath the mental foramen an elevation, the external oblique line,
extends upwards and outwards to the anterior border of the ramus.
The deep surface is marked, on each side of the symphysis, along the
inferior margin, by an oval depression, indicating the anterior attach-
ment of the digastric muscles, and above them by two pairs of

Fig. 47. Fig. 47.—Tur Inrertor Max-
ILLARY BonE, FROM THE
RIGHT SIDE AND ABOVE, (A.
TS) er

1, the body; 2, the sym-
physis; 3, the ramus; 4, the
angle, near it the oblique ridges
marked by the attachment of
the masseter muscle; 5, the
coronoid process; 6, the con-
dyle or articular head ; 7, placed
in the sigmoid notch, points to
the front of the neck ; 8, the
mental foramen ; 9, the external
oblique ridge ; 10, the inferior
dental foramen and mylo-hyoid
groove of the left side. This
figure represents a full set of
the teeth of the lower jaw in
middle life. (See also, for the view of the inner surface of the lower jaw, figure 54, the
vertical section of the skull.)

prominent tubercles, spine mentales, placed closely together, giving
attachment, the upper pair to the genio-hyo glossi, and the lower to
the genio-hyoidei_ muscles. An oblique prominent line, the mylo-
hyoidean ridge, leading from beneath the spinee mentales, upwards and
outwards to the ramus, gives attachment to the mylo-hyoideus muscle.
Above this line is a smooth depression for the sublingual gland, and
beneath and external to it another for the submaxillary gland.

The ramus is thinner than the body of the bone. Its posterior border
in meeting the line of the base forms the angle of the jaw. The
external surface is flat and uneven, and towards the angle stronger
ridges mark the place of attachment of the masseter muscle. ‘The
internal surface presents at its middle the inferior dental foramen, leading
into the dental canal, which lodges the dental nerve and vessels. Passing

HYOID BONE. 55

down from the sharp inferior margin of this foramen is the mylo-hyoid
groove (occasionally a canal for a short space), marking the passage of
the mylo-hyoid nerve with an accompanying artery and vein. Behind
this, inside the angle, is a marked roughness for the internal pterygoid
muscle.

Each ramus is surmounted by two processes, the condyle and the
coronoid, which are separated by a deep excavation, the siymoid noich.
The condyle is continued upwards from the posterior part of the ramus.
It is supported bya constricted portion, the neck, which presents anteriorly
a depression, into which the external pterygoid muscle is inserted. ‘The
condyle is a transversely elongated convex articular process, whose
major axis is directed obliquely, so that if prolonged it would meet
with that of its fellow near the anterior margin of the foramen magnum.
The coronoid process is continued vertically upwards in front, from the
anterior margin of the ramus. It is pointed, and gives attachment by
its margin and inner aspect to the temporal muscle. At its base, in
front, is a groove, to which the buccinator muscle is attached.

The anterior margin of the ramus is placed at nearly a right angle to the
alveolar border. The angle of the jaw, which is the meeting of the posterior
border of the ramus with the base, is in the adult usually about 120° ; in infancy
it is as great as 140° or more ; in strongly developed jaws it may be diminished to
110° or less; and in old and toothless jaws it is increased. These changes are
connected with a variety of circumstances, among which may be noticed,—the
development of the temporary and permanent teeth, the absorption of the
alveolar arch after the loss of the teeth in advanced age, the elongation of the
face and upper jaw towards adult life, and the varying state of development of
the masseter muscles at different periods,

THE HYOID BONE.

The hyoid bone, or os lingua, is situated at the base of the tongue,
and may be felt between the chin and the thyroid cartilage. It is
shaped like the letter v, and consists of a body and two pairs of cornua.
It is suspended from the tips of the styloid processes of the temporal
bones by a pair of slender bands, the stylo-hyoid ligaments, which in
most animals usually form distinct bones. Though belonging rather to
the neck than to the cranium or face, it may properly be considered in
this place.

Fig. 48.—Tur Hyorp Bong, FroM BEFORE. 3 Fig. 48.

1, the prominent part of the body; 2, the great cornu ;
3, the lesser cornu.

The Jody, or central piece, basi-hyal, is com-
pressed from before backwards, and lies in a
plane, directed downwards and forwards. Its
anterior surface is convex, and marked in the middle by a vertical
ridge, on each side of which are depressions for the attachment of muscles.
Its posterior surface is concave, and is directed towards the epiglottis.

The great cornua, thyro-hyals, project backwards from the sides of the
body, and end in rounded extremities.

The small cornua, or cornicula, cerato-hyals, short and conical, project
upwards and backwards from the place of junction of the body with
the great cornua, and give attachment at their extremities to the stylo-

56 BONES OF THE HEAD.

hyoid ligaments. They continue for a long time movable, as the
cartilage which connects them remains unossified till an advanced
period of life.

THE SKULL AS A WHOLE.
THE SUTURES.

With the exception of the lower jaw, which is articulated movably
with the temporal bone, all the bones of the skull are closely fitted
together by more or less uneven edges or surfaces. To those articula-
tions which are markedly serrated the name of swfwve is given.

The sutures of the skull are best named from the bones between
which they lie, as, for example, occipito-parietal, occipito-mastoid,
fronto-ethmoid, parieto-sphenoid, &e. ‘The arch of the skull is inter-

Fig. 49. Fig. 49.—Front View oF
Mate SKULL AT ABOUT
Twenty Years, (A. T.) $

1, frontal eminence ; 2,
glabella, between the super-
ciliary eminences, and above
the transverse suture of
union with the nasal and
superior maxillary bones ;
3, supra-orbital ridge near
the supra-orbital notch ; 4,
in the orbit on the orbital
plate of the sphenoid bone,
between the foramen lacerum
orbitale and the spheno-
maxillary fissure; 5, the
anterior opening of the
nares, within which are seen
in shadow the nasal crest of
the superior maxillary bones,
the vertical plate of the eth-
moid bone, and on each side
the turbinated bones; 6,
superior maxillary bone at
the canine fossa—above the
figure is the infra-orbital
foramen ; 7, myrtiform, or
incisor fossa; 8, malar bone ;
9, symphysis menti and
median ridge ; 10, body of
the lower jaw, above the
outer oblique ridge and the
mental foramen ; 11, vertex,
near the coronal suture; 12,
temporal fossa ; 13,zygoma ;
14, mastoid process; 15,
angle of the jaw ; 16, mental
angle. In this skull there are fourteen teeth in each jaw, the wisdom teeth haying not
yet appeared.

sected superiorly by three great serrated sutures, two of which, placed
transversely, correspond to the anterior and posterior margins of the
parietal bones, while the third passes between them in the middle line.
On each side also an irregular longitudinal line of suture runs from the

THE SUTURES. St

malar to the occipital bone, bounded by the frontal and parietal bones
above, and the malar, sphenoid, and temporal bones below.

The fronto-parietal, or coronal suture, connects the frontal and the
two parietal bones. It commences at each side, about an inch behind
the external orbital process of the frontal bone, above the great wing
of the sphenoid, and mounts upwards and backwards to the vertex.
It presents the most marked dentations in the middle of each lateral
half; at the summit the serrated surface is oblique, the frontal bone
overlapping the parietal, while similarly at the lower part the parietal
overlaps the frontal. vt

The occipito-parietal, or lambdoidal suture, between the occipital and
parietal bone, inclines downwards and outwards on each side and. has
somewhat of the form of the Greek letter A. The occipito-mastoid
suture is in continuation with it.

Fig. 50.—LATERAL View OF THE SKULL REPRESENTED In Ficure 49. (A.T.) 3

1, frontal bone ; 2, parietal bone at the temporal ridge ; x x, coronal suture ; 3, on
the occipital bone at the lower end of the lambdoidal suture, near its meeting with the
occipito-mastoid and parieto-mastoid sutures ; 3’, external or posterior occipital protuber-
ance ; 4, great wing of the sphenoid bone ; 5, squamous part of the temporal bone ; 6,
the same at the root of the zygoma, immediately over the meatus auditorius externus ;
7, mastoid portion of the temporal bone, in front of which is the mastoid process ; 8, the
left condyle of the occipital bone ; 9, the anterior opening of the nares ; 10, on the lachry-
mal bone in the inner wall of the orbit ; 11, malar bone, near its junction with the
zygoma ; 12, superior maxillary bone behind the canine fossa; 13, ramus of the lower
jaw ; 14, body of the lower jaw, near the mental foramen.

58 BONES OF THE HEAD.

The interparietal, or sagittal suture, connects the two parietal bones :
it is continued in children, and occasionally in adults, by a suture
between the two halves of the frontal bone, the frontal suture. In the
much elongated forms of skull the sagittal suture is often found par-
tially or wholly obliterated by ossification.

The ¢emporo-parietal suture consists of two very distinct parts, the
squamous suture, arched in direction, in which the scale-like margin of
the squamous portion of the temporal bone overlays the similar margin
of the parietal, and the parielo-mastoid suture, which is thick and
serrated.

The spheno-parietal suture, between the parietal bone and great
wing of the sphenoid, is about half an inch in extent. It is absent
only in very rare cases, and then the frontal and temporal bones come
into contact.

The name of transverse has by some anatomists been given to the series of
sutures which unite the facial and orbital margins of the frontal to other bones,
as the malar, sphenoid, ethmoid, lachrymal, maxillary, and nasal. The lines of
union between the other bones, though more or less serrated, have not received
any special designation, but may be named from the bones between which they
run, as for example, petro-occipital, petro-sphenoid, inter-maxillary, palato-
pterygoid, &e.

Ossa Triquetra.—Separate pieces of bonc are foundin many skulls, interposed
between the cranial bones, They are called ossa triquetra, ossa Wormii, ossa
suturarum, &e. They are of irregular form, with margins adapted to the cha-
racter of the sutures in which they are situated, They are most frequently found
in the occipito-parietal suture, where they occur sometimes in great numbers,
more or less symmetrically arranged; in other instances, one or several bones of
considerable size may occupy the place of the superior part of the occipital, and
may correspond to the interparietal bone of some animals, They are much less
frequently found in the other sutures,

EXTERNAL SURFACE OF THE SKULL,

The external surface of the skull may be conveniently divided into
superior, inferior, anterior, and lateral regions.

The superior region, extending from the supra-orbital ridges in
front to the superior curved line of the occipital bone behind, and
bounded laterally by the temporal ridges, is smooth and convex, covered
only by the integument and by the muscular fibres and fascia of the
occipito-frontalis muscle. It is of an oval form, broader in the parietal
than the frontal region, flattened in front, and projecting somewhat in
the middle behind. There is also a slight projection from the general
curve at each of the frontal and parietal eminences.

The anterior region of the skull, below the forehead, presents the
openings into the orbits, bounded by the frontal, malar, and superior
maxillary bones; and between the orbits, the bridge of the nose,
formed by the nasal bones and ascending processes of the superior
maxillaries. Below the nasal bones is the nasal aperture, of an inverted
heart shape: its thin margin gives attachment to the nasal cartilages,
and projects forwards in the middle line below as the nasal spine.
Below the nasal aperture are the incisor fosse of the upper jaw ;
below the orbits are the canine fossz ; and external to the canine fossz
are prominences of the cheeks, formed by the anterior inferior parts
of the malar bones. The lower Jaw completes the skeleton of the face.

EXTERIOR OF THE SKULL. THE ORBITS. 59

The foramina in this region, on each side, are the supra-orbital fora-
men or notch in the superior margin of the orbit, the infra-orbital
foramen below the inferior margin of the orbit, the mental foramen of
the lower jaw, and the small irregular foramina of the malar bone.

The orbits are pyramidal fosse, irregularly quadrilateral, with their
bases directed forwards and slightly outwards, their inner walls being
nearly parallel, and their outer walls diverging so as to be nearly at
right angles to each other. The roof of each orbit is formed by the

Fig. 51

Fig. 51.—Sectrion or Mane Sxutn oF Mippne AGE, IN TWO PLANES, ONE PASSING
VERTICALLY THROUGH THE LEFT ORBIT, THE OTHER OBLIQUELY FROM BEHIND THE
ORBIT, BACKWARDS AND OUTWARDS, THROUGH THE TympanuM AND Masrorp Pro-
cuss: (A. 7) 3

1, section of the frontal bone in the roof of the orbit ; 2, left nasal bone ; 3, nasal
process of the superior maxillary bone ; 4, left lachrymal bone, and in front the lachrymal
groove ; 5, placed on the os planum of the ethmoid bone, below the anterior eth-
moidal foramen ; 6, is placed below the root of the lesser wing of the sphenoid bone,
between the optic foramen and the posterior ethmoidal foramen, and in front of
the foramen lacerum orbitale ; 7, orbital plate of the superior maxillary bone inside
the infra-orbital groove; 8, on the orbital plate of the palate bone, in front of and
above the spheno-palatine foramen and spheno-maxillary fossa ; 9, the upper extremity of
the posterior palatine canal ; 10, the cranial opening of the foramen rotundum—its
anterior opening is seen in the spheno-maxillary fossa ; 11, section of the great wing of
the sphenoid bone outside the foramen ovale, and in the fossa near it the anterior opening
of the Vidian canal ; 12, placed between the spinous and oval foramina ; 13, on the
anterior surface of the petrous bone, near the apex. In front of the figure is seem the
sigmoid groove of the internal carotid artery, and below the figure and externally the
hiatus Fallopii; 14, the pituitary fossa, with the anterior and posterior clinoid pro-
cesses ; 15, section of the petrous bone above the labyrinth ; two of the semicircular
canals are opened ; immediately below is the tympanum. The inner wall is seen with
the promontory, fenestra ovalis and pyramid in shadow ; forwards near x, the tympanic
opening of the Eustachian canal, and backwards, below 16, the opening into the mastoid
cells ; 17, left styloid process—that of the right side is seen in perspective below the
skull, close by the occipital condyle ; 18, tuberosity of the superior maxilla ; 19, canine
fossa ; 20, nasal notch and anterior nasal spine ; 21, inner wall of the antrum seen by
the removal of its outer wall ; above the figure is the maxillary process of the inferior
turbinated bone, and over that an irregular fissure, viz., the opening of the antrum into
ae middle meatus of the nose, and above that the uncinate process of the ethmoid

one. .

60 BONES OF THE HEAD.

orbital process of the frontal and the small wing of the sphenoid
bone; the floor by the orbital processes of the malar and superior
maxillary bones, and by the small orbital surface of the palate bone
at the back part; the inner wall by the ascending process of the
superior maxillary, the lachrymal, the ethmoid, the sphenoid, and
sometimes, the palate bone ; and the outer wall by the orbital surfaces
of the malar bone and great wing of the sphenoid. The sphenovdal
Jissure (foramen lacerum orbitale), at its inner extremity, occupies the
apex of the orbit, while its outer and narrower part lies between
the roof and the external wall. The foramen opticum is internal and
superior to the sphenoidal fissure. In the angle between the external
wall and the floor is the spheno-mazillary fissure, bounded by the
sphenoid, palate, superior maxillary, and malar bones, and leading
into the spheno-maxillary fossa at its back part, and the zygomatic fossa
at its fore part. Passing forwards. from the margin of the spheno-
maxillary fissure is the commencement of the infra-orbital canal, groov-
ing the posterior part of the floor of the orbit. On the inner wall in
front is the lachrymal groove, formed by the superior maxillary and
lachrymal bones, and leading into the nasal duct: further back,
between the ethmoid and frontal bones, are the anterior and posterior
ethmoidal foramina; on the roof at its anterior margin, ig the
supra-orbital foramen or notch; within the external angular process is
the fossa for the lachrymal gland; and in the outer wall are one or two
minute foramina which perforate the malar bone.

The lateral region of the skull presents in a horizontal line from
behind forwards the mastoid process, the external auditory meatus, the
elenoid fossa, with the condyle of the lower jaw, and the zygomatic or
malar arch, formed by the zygomatic process of the temporal bone and
the posterior part of the malar. When the head of the lower jaw is in
the glenoid cavity, the coronoid process lies internal to the malar arch.
The upper part of the space bridged over by this arch is called the
temporal fossa, the lower part the zygomatic fossa, the line of division
being the rough ridge which divides the external surface of the great
wing of the sphenoid bone into an upper and lower portion. The
temporal fossa is occupied by the temporal muscle; it is bounded
superiorly by the temporal ridge; and the frontal, parietal, sphenoid
and malar bones take part in its formation. The zygomatic fossa is
occupied in part by the external pterygoid muscle; its wall is formed
internally by the external pterygoid plate, superiorly by the lower part
of the great wing of the sphenoid bone, and anteriorly by the superior
maxillary. Inferiorly the external pterygoid plate comes nearly into
contact with the superior maxillary bone, but is almost always separated
from it by a thin portion of the pyramidal process of the palate bone ;
superiorly, it is divided from itby the pterygo-mazillary fissure, a vertical
opening, which leads into the spheno-maxillary fossa, and which is con-
tinued above into the outer extremity of the horizontal spheno-maxillary
fissure opening into the orbit.

The spheno-mazillary fossa is the space which lies in the angle
between the pterygo-maxillary fissure and the inner part of the spheno-
maxillary fissure. It is bounded posteriorly by the external pterygoid
process and lower part of the anterior surface of the great wing of the
sphenoid bone, anteriorly by the superior maxillary bone, and internally
by the vertical plate of the palate bone. Into this-narrow space five

BASE OF THE SKULL. Gi

foramina open, viz., on the posterior wall, the foramen rotundum, the
Vidian canal, and, between the sphenoidal process of the palate bone
and the root of the internal pterygoid plate, the pterygo-palatine canal ;
on the inner wall, the spheno-palatine foramen formed by the palate bone
and a small part of the sphenoidal spongy bone, and opening into the
nasal cavity ; and inferiorly, the posterior palatine canal, which leads
down to the palate between the palatal and superior maxillary bones.

The external base of the skull, excluding the lower jaw, is divisible
into three parts, anterior, middle, and posterior.

The anterior division consists of the palate and the alveolar arch. It
is traversed longitudinally by a mesial suture, and transversely by that

Fig. 52. —ExtTErNAL Basis Fig. 52
OF THE SKULL SHOWN
Iw Figure 49. (A.T.) $

1, palatine plate of the
superior maxillary bone
near the mesial suture ; 2,
palatine plate of the palate
bone below the palato-
maxillary suture; 3, the
anterior palatine foramen ;
4, is placed outside the
posterior palatine foramen,
inside the tuberosity of
the superior maxilla, and
in front of the smaller
posterior palatine foramina,
in the pyramidal process of
the palate bone ; 5, inner
surface of the external
pterygoid plate of the
sphenoid bone ; 6, is placed
within the posterior open-
ing of the left nasal fossa
on the internal pterygoid
plate ; 7, the vomer; x,
the posterior opening of
the pterygo-palatine canal
in front of the foramen la-
cerum anterius; 8, spheno-
maxillary fissure leading
into the orbit ; 9, foramen
spinosum ; 10, foramen
ovale ; 11, placed on the
apex of the petrous bone,
between the foramen lace-
rum anterius and the in-
ferior opening of the carotid
canal ; 12, the jugular fossa of the temporal bone, and foramen lacerum posterius ; 13,
on the articular eminence of the inner root of the zygoma ; 14, meatus auditorius externus ;
15, glenoid fossa in front of the fissure of Glaser ; 16, tympanic plate or posterior part ot
the glenoid fossa, close to the styloid process, below which is seen the stylo-mastoid fora-
men ; 17, mastoid process, and to its inside the digastric and occipital grooves; 8,
basilar process of the occipital bone, and in front the mark of the still incomplete union
with the body of the sphenoid bone ; 19, condyle of the occipital bone ; 20, is placed in
the foramen magnum, and points to the lower opening of the anterior condylar foramen ;
21, posterior condylar foramen ; 22, jugular process of the occipital bone, and to its inner
side the jugular notch ; 23, external occipital spine running down from the protuberance ;
24, superior curved line of the occipital bone ; 25, inferior curved line ; 26, groove and
ridge of insertion of obliquus capitis superior muscle.

62 BONES OF THE HEAD.

between the maxillary and palate bones. Anteriorly, in the middle
line, is the anterior palatine foramen, with the four smaller foramina
contained within it ; posteriorly, on each side, at the base of the alveolar
arch, is the posterior palatine foramen, and externally and posteriorly
to that, the posterior and external small palatine foramina. The palate
is surrounded in front and on the sides by the alveolar arch bearing the
teeth of the upper jaw.

The middle division extends back to the front of the foramen magnum.
Its central portion has been called the guttural fossa. In the middle
line is the basilar process of the occipital bone, and in front of that the
body of the sphenoid bone, covered anteriorly by the extremity of the
vomer. On each side, the petrous portion of the temporal bone reaches
as far forwards as the extremity of the basilar process ; and between the
petrous and squamous portions of the temporal is the back part of
the great wing of the sphenoid bone. Between this division of the base
of the skull and the palate are the posterior nares, separated by the
vomer, and bounded above by the body of the sphenoid bone, below by
the horizontal plates of the palate bones, and on the sides by the internal
pterygoid processes. Between the pterygoid plates is the pterygoid.
fossa; and placed in an oblique line backwards and outwards from this
are the foramen ovale, foramen spinosum, and processus spinosus;
while behind and parallel to these is a groove for the Eustachian tube,
formed by the margins of the sphenoid bone and pars petrosa, leading
into the Eustachian orifice, and in a line with the fissure of Glaser.
Between the apex of the pars petrosa, the basilar process, and the
sphenoid bone, is the foramen lacerum medium, on the external wall of
which opens the carotid canal, and on the anterior the Vidian canal ;
it is closed inferiorly by a plate of cartilage, and its area is crossed by
the internal carotid artery and the Vidian nerve. Behind the pars
petrosa, and bounded posteriorly by the jugular fossa of the occipital
bone, is the foramen jugulare, or foramen lacerum posterius: it is divided
into a large rounded part situated externally and posteriorly, bounded
in front by the jugular fossa of the temporal bone, and occupied by the
jugular vein; anda narrow angular part situated anteriorly and in-
ternally, bounded by a portion of the pars petrosa distinct from the
jugular fossa, and transmitting the eighth pair of cranial nerves.
These two parts are sometimes separated by a spiculum of bone. In
front of this is the carotid foramen, on its outside is the stylo-mastoid
foramen and styloid process, and internal to it is the anterior condyloid
foramen.

The posterior division presents on each side of the foramen magnum,
from within outwards, the occipital condyle, the rough surface for the
rectus capitis lateralis muscle, the occipital groove of the temporal bone,
the digastric fossa, and the mastoid process. Behind the foramen mag-
num is the tabular part of the occipital bone, with its ridges and
muscular impressions.

THE INTERIOR OF THE CRANIUM.

The walls of the cranium consist of two layers of compact bony sub-
stance, the outer and nner tables, and an intervening cancellated
substance, called diploe. The inner or vitreous table, has a smooth,
close-grained, shining appearance, is hard and brittle, and presents

INTERNAL BASE OF THE SKULL. 63

irregular digitate impressions corresponding to the convolutions of the
brain. The thinnest portions of the cranial wall are the cribriform
plate of the ethmoid and the orbital plates of the frontal bone, in both
of which the diploe is entirely absent; the bone is also thin and
compact in the middle part of the inferior occipital fossee, and in the
squama and glenoid fossa of the temporal,

The upper part of the cranial cavity consists of a single vaulted
dome formed by the frontal, parietal, and occipital bones. It ismarked
by the superior longitudinal grooves, by shallow cerebral impressions,
by small ramified meningeal grooves, and by Pacchionian fossx of
varying depth. The lower part or znternal basis of the skull is divided
into three fossee, named anterior, middle, and posterior.

The anterior fossa, formed by the orbital plates of the frontal bone,
the small wing of the sphenoid, and the cribriform plate of the ethmoid,
supports the anterior lobes of the brain. It sinks into a hollow at the

Fig. 53. — Iyrernat
BASIS OF THE SKULL.
(A. T.) 4

1, anterior fossa and
roof of the orbit, as
formed by the frontal
bone, marked by im-
pressions of cerebral
convolutions ; between
2 and 3, the foramen
cecum, crista galli and
cribriform plate of eth-
moid; 3, ethmoidal
spine of the sphenoid ;
4, lesser wing of sphe-
noid terminating poste-
riorly in the anterior
clinoid process, inside
which is the optic fora-
men; 5, placed in the
pituitary fossa, behind
the olivary eminence and
transverse groove of the
optic commissure; 6,
dorsum sellz, termina-
ting in the posterior
clinoid processes, and
to the side of these the
groove of the internal
carotid artery ; 7, fora-
men rotundum, in front
of which, but not seen in
the figure, is the foramen
lacerum orbitale ; 8, foramen ovale ; 9, foramen spinosum ; 10, on the ridge of the petrous
bone, near its apex, and to the inside of the hollow occupied by the Gasserian ganglion ;
in front of this is the foramen lacerum medium ; 11, in front of the eminence of the
superior semicircular canal of the labyrinth, and behind the hiatus Fallopii ; 12, the pro-
minent ridge of the petrous bone, marked by the superior petrosal groove; 13, the
posterior surface of the petrous bone—to the inside, the meatus auditorius internus,
behind, the scale of bone covering the aqueduct of the vestibule; 14, basilar groove ;
15, anterior condylar foramen ; 16, jugular part of the foramen lacerum posterius ; 17,
groove of the lateral sinus ; 18, internal occipital protuberance, and running down from
it the internal occipital spine ; between 17 and 18, the upper part of the groove of the
lateral sinus, between 17 and 16, the lower part ; 19, cerebellar fossa.

64 BONES OF THE HEAD.

cribriform plate of the ethmoid where it is pierced by numerous small
foramina and rises to a convexity over the orbits, The foramen cecum
is situated in front of the crista galli of the ethmoid bone.

The middle fossa, on a lower level than the anterior, presents a mesial
and two lateral parts. The mesial part is small, being formed by the
olivary process and sella turcica of the sphenoid bone, and limited be-

Fig. 54,

Fig. 54.—AnrvEro-Posterior Vertican Section or THE ApDULT SKULL A LITTLE TO
THE LEFT OF THE MIDDLE LINE. (A. T.) 3

1, nasal bone ; 2, perpendicular plate of the ethmoid bone, with olfactory foramina
and grooves at its upper part ; 8, vomer; 4, nasal process of the right superior maxillary
bone, forming part of the wall of the right nasal fossa ; below this, the anterior extremity
of the right inferior turbinated bone overhanging x, which is the right inferior meatus of
the nose ; 5, crista galli ; 6, inner surface of the frontal bone; 7, of the parietal bone ;
8, squamous part of the temporal ; 9, on the occipital bone below the internal occipital
protuberance ; 10, external occipital protuberance ; 11, on the condylar process below
the anterior condylar foramen ; 12, on the posterior surface of the petrous bone below
the meatus auditorius internus ; between 9 and 12, the groove of the right lateral sinus ;
13, placed above the sella turcica ; 14, part of the left frontal sinus ; 15, part of the left
sphenoidal sinus, the figure being placed on the septum of the sinuses ; 16, hard palate
and alveolar arch—the figure is placed near the lower opening of the posterior palatine
canal, and the grooves which extend forwards from it ; 17, anterior nasal spine ; 18,
section of the left superior maxillary bone, and near the place to which the line points,
the section of the lower part of the anterior palatine canal ; 19, on the inner surface of
the ramus of the lower jaw, below the sigmoid notch, and above the inferior dental fora-
men ; 20, inner surface of the body of the jaw on the mylo-hyoid ridge ; 21, surface of
section of the lower jaw to the left of the symphysis ; behind the symphysis, and between
21 and 22, the mental spines ; 23, groove for the mylo-hyoid nerve.

NASAL CAVITIES AND AIR SINUSES. 65

hind by the dorsum sellz. The lateral part on each side, formed by
the great wing of the sphenoid, the squamous part, and the anterior
surface of the petrous part of the temporal, lodges the temporal lobe of
the brain. ‘he foramina of the middle fossa are the foramen opticum,
the sphenoidal fissure, foramen rotundum, foramen ovale, foramen
spinosum, foramen lacerum anterius, and hiatus Fallopii.

The posterior fossa, deeper and larger than the others, extends back
to the occipital protuberance, and lodges the cerebellum and medulla
oblongata. The occipital bone and the petrous and mastoid portions
of the temporal bone take part in its formation. In the posterior
surface of the pars petrosa, which limits this fossa anteriorly on each
side, is the internal auditory meatus; lower down is the foramen
lacerum posterius; between that and the foramen magnum is the
anterior condylar foramen.

Grooves for Bloodvessels—The groove of the middle meningeal
artery commences at the foramen spinosum of the sphenoid bone, and
ramifies principally on the squamous portion of the temporal bone and
on the parietal. The groove of the internal carotid artery lies on the
side of the body of the sphenoid bone, and terminates inside the anterior
clinoid process. ‘The groove of the superior longitudinal sinus, com-
mencing at the foramen ccecum, passes backwards in the middle line of
the roof of the skull, and terminates at the internal occipital protuber-
ance. From that point the grooves of the lateral sinuses pass outwards
on the occipital bone, cross the posterior inferior angles of the parietal
bones, descend on the mastoid portions of the temporal bones, run
inwards again on the occipital, and turn forwards to terminate at the
jugular foramen. The groove of the inferior petrosal sinus lies between
the petrous portion of the temporal bone and the basilar process ; that
of the superior petrosal sinus extends along the superior angular edge
of the petrous portion.

THE NASAL CAVITIES AND COMMUNICATING AIR SINUSES.

The nasal cavities, or fossee, are placed one at each side of a median
vertical septum. They open in front and behind by the anterior and
posterior nares already described, and communicate by foramina with
the sinuses of the frontal, ethmoid, sphenoid, and superior maxillary
bones. Their vertical extent, as well as that from before backwards,
is considerable, but their transverse width is very limited, especially
in the upper part.

The internal wall, or septum narium, is formed principally by the
central plate of the ethmoid bone, the vomer, the frontal spine, the
rostrum of the sphenoid bone, and the crests of the maxillary and palate
bones. It presents a great angular deficiency in front, which in the
recent state is filled up by the septal cartilage. In very many cases it
deviates from the middle line, and more frequently to the left than to
the right side.

The roof is horizontal in its middle part, but sloped downwards be-
fore and behind. The middle part is formed by the cribriform plate of
the ethmoid bone, the fore part by the frontal and nasal bones, and the
back part by the sphenoidal spongy bone.

The floor, formed of the palate plates of the maxillary and palate
bones, is smooth, and concave from side to side. Towards its anterior

extremity is the superior orifice of the incisor canal.
VOL. I. F

66 BONES OF THE HEAD.

The external zwall is the most extensive. The bones which take part
in its formation are the nasal, superior maxillary, ethmoid, inferior
spongy, and palate bones, and the internal pterygoid plates. The
superior and inferior turbinated parts of the ethmoid bone (ethmo-
turbinal bone), and the inferior spongy bone (maxillo-turbinal), project-

Fis. 55. Fig. 55.—VerticaL ANTERO-
PosTERIOR SECTION OF A Part
OF THE CRANIUM, SHOWING
THE OuTER WALL OF THE Lurr
Nasat Fossa, &c. (A. 7.) 2

r
S

1, nasal bone; 2, nasal pro-
cess of the superior maxillary
bone ; 3, ascending plate of the
palate bone; 4, superior turbi-
nated bone of the ethmoid—
below it the superior meatus,
behind it the opening into the
left sphenoidal sinus; 5, the
middle turbinated bone—below
it the middle meatus, into which
opens the maxillary sinus ; superi-
orly and anteriorly, is the common
opening of the infundibulum and
anterior ethmoidal cells ; behind
it, and above 3, the spheno-
palatine foramen ; 6, the inferior
turbinated bone—below it the
inferior meatus x x ; below these marks the section of the palatine plates of the left
palate and superior maxillary bones ; 7, the left frontal sinus; 8, the left sphenoidal
sinus ; 9, the left optic foramen in the root of the lesser wing of the sphenoid, and
anterior clinoid process ; 10, the ridge of the dorsum selle divided ; and between 9 and
10, the sella turcica ; 11, the posterior surface of the petrous bone, close to the
internal auditory meatus ; 12, the basilar process of the occipital bone, close to the
foramen lacerum posterius ; 13, below the anterior condyloid foramen ; 14, left styloid
process ; 15, external, and 16, internal pterygoid processes ; 17, posterior palatine canal
and grooves.

ing inwards, overhang the three divisions of the nasal fosse, called
meatus. The superior meatus, very short, is placed between the superior
and inferior turbinated parts of the ethmoid bone ; into it open anteriorly
the posterior ethmoidal cells, and posteriorly the spheno-palatine fora-
men and sphenoidal sinus. The mdddle meatus, the space between the
inferior turbinated part of the ethmoid and the inferior spongy bone,
communicates at its fore part by means of the infundibulum, with the
anterior ethmoidal cells, and with the frontal sinus, while in its middle is
the opening of the maxillary sinus. The enferior meatus, longer than
the others, lies between the inferior spongy bone and the floor of the
nasal cavity ; in its fore part is the orifice of the nasal duct and the
anterior palatine canal.

The air sinuses are hollows within the ethmoid, frontal, sphenoid,
and maxillary bones, which communicate with the nasal cavities by
narrow orifices. With the exception of the maxillary sinus these
cavities are absent in early youth. The mavillary sinus begins to be
formed about the fourth month of foetal life ; the frontal, ethmoidal, and
sphenoidal first appear during childhood, but remain of small size up
to the time of puberty, when they undergo a great enlargement. In
advanced life they all increase in size by absorption of the cancellated

OSSIFICATION OF THE BONES OF THE HEAD, 67

tissue in their vicinity. The ethmoidal sinuses consist of several irregular
spaces occupying the lateral masses of the ethmoid bone. The
anterior open into the infundibulum, the posterior into the superior
meatus. The frontal sinuses are placed between the outer and inner
tables of the frontal bone over the roof of the nose. They extend out-
wards from behind the glabella to a variable distance over the orbit,
being separated from each other by a thin bony septum. They open
into the middle meatus of the nose through the infundibula. The
sphenoidal sinuses occupy the anterior part of the body of the sphenoid
bone, being formed in connection with the sphenoidal spongy bones.
They are separated by a median septum, and open anteriorly behind
and above the superior meatus of the nose.

The maxillary sus is of an irregular pyramidal form; its apex
points to the malar tuberosity ; its inner wall, which separates it from
the nasal cavity, is formed by the maxillary, palate, and inferior
turbinated bones, and the uncinate process of the ethmoid ; its other
sides are formed by the superior maxillary bone, an irregular gap or
deficiency being left between the uncinate process and the inferior
turbinated bone, by which the sinus opens into the middle meatus.
The alveolus of one of the molar teeth generally forms a marked pro-
jection in the floor of the sinus, at its outer part.

OSSIFICATION OF THE BONES OF THE HEAD.

Some of these bones originate in cartilage, and others in membrane, or un-
‘chondrified formative tissue.

To the first set belong chiefly the bones of the base of the cranium, viz., the
occipital, sphenoid, ethmoid, petro-mastoid, and inferior turbinated, together with
the small bones of the ear, the styloid process, and hyoid bone. All the other
bones of the cranium and face originate in membrane or formative tissue. The
parts of the bones which are median or central—the basi-occipital, basi-sphenoid,
pre-sphenoid, and mesethmoid—arise either from one median centre each, or from
more numerous centres, which coalesce into one at an early period. The other
bones or their parts are all in pairs, although some of them, as the frontal, ex-
occipital, ethmo-turbinal, alisphenoid, orbito-sphenoid, and lower jaw finally
coalesce with each other or with a median portion.

In the tabular bones ossification usually spreads outwards from certain centres,
and the marginal portions, in the earlier stages, present more or less the form of
radiated fibres or spicula. The sutured edges, and especially the angles of the
‘bones, are incomplete, the bones being united together at their margins by fibrous
tissue. The diploe and sinuses are at first absent, some of the latter arising early
in life, and others being formed at a comparatively late but variable period.

The occipital bone. This bone at birth, and for some time afterwards, con-
sists of four separate pieces—a basilar, a tabular, and two condylar parts, united
together by intervening cartilage. The lines of junction of the basilar and con-
‘dylar parts pass through the condyles near their anterior extremities ; those of
the condylar and tabular parts extend outwards from the posterior margin of the
foramen magnum. The basilar and condylar parts arise each from one osseous
nucleus, which appears from the seventh to the eighth week. A few days earlier
there appear in the tabular part usually four nuclei, placed in pairs above and
below the occipital protuberance. These nuclei speedily unite to form a single
thin tabular mass. Four fissures, however, remain, two median and two lateral
running in from the margins of the bone, and marking the limits of the original
pieces. These fissures, especially the lateral, sometimes remain visible for several
years, simulating fractures. The largest ossa Wormii, when symmetrical, may arise

from the persistence of the upper and lateral fissures, The osseous union of the
F 2

68 BONES OF THE HEAD,

condylar and tabular parts, beginning in the second or third, is completed in
the fourth year ; that of the basilar and condylar parts, beginning in the third or
fourth, is completed in the fifth or sixth year. The basi-occipital is united to

Fig. 56. B Fig. 56.—OssIFICATION OF THE
OccrPITAL Bonk (R. Quain).

A, in a foetus of 10 weeks
(from Meckel, Archiv, vol. i.
tab. vi.) ; a, upper or tabular
part; 1 & 2, lower and upper
pairs of ossific centres in it ;
6, lower part or basilar and
condylar portions : ossific cen-
tres are seen in the condylar
portions,

B, occipital bone of a child
at birth ; a, upper or tabular
part, in which the four centres
have become united into one,
leaving fissures between them ;
b, b, the ossified condylar por-
tions ; ¢, the basilar portion.

the basi-sphenoid by intervening cartilage up to the twentieth year, after which
ossific union begins and is completed in one or two years.

The parietal bone is ossified from a single nucleus, which appears in the
parietal eminence about the seventh or eighth week. The eminence is very
conspicuous in the young bone, and gives a marked character to the form of
the skull for a number of years in early life.

The frontal bone is ossified from two nuclei which appear one on each side
above the orbital arch, about the seventh week. At birth the bone consists of

Fig. 57. Fig. 57.—Frontan Bone or A Farus SHORTLY
BEFORE Birr (R. Quain).

a & 6 indicate the two separate portions of
the bone, in each of which the radiation of
bony spicula from the frontal eminence is
seen.

two separate lateral portions, which unite
by a vertical median suture during the
first year. This frontal suture usually
becomes obliterated by osseous union
taking place from below upwards, during
the second year, though not unfrequently
it persists throughout life. The frontal sinuses appear during the first year, and
go on increasing in size up to old age.

The Fontanelles. These are membranous intervals between the incomplete
angles of the parietal and neighbouring bones, in some of which movements of
the soft wall of the cranium may be observed in connection with variations in
the state of the circulation and respiration. They are four in number, two
median, anterior and posterior, and two lateral. The anterior fontanelle, situated
between the anterior superior angle of the parietal bones and the superior angles
of the ununited halves of the frontal bone, is quadrangular in form, and remains
open for some time after birth. The posterior fontanelle, situated between the
posterior superior angles of the parietal bones and the superior angle of the
occipital bone, is triangular in shape. It is filled up before birth, but the edges
of the bones, being united by membrane only, are still freely movable upon each
other. The lateral fontanelles, small and of irregular form, are situated opposite

OSSIFICATION OF THE TEMPORAL BONE. 69

the posterior inferior angles of the parietal bones. The fontanelles are gradually

Fig. 58.—Sxutn or A Cuinp AT BIRTH, SEEN

FROM ABOVE (from Leishman). 4

a, superior fontanelle ; p, posterior fontanelle ;
b, b, parietal eminences ; for the lateral fontanelles,
see fig. 65, p. 77.

filled up by the extension of ossification
into the membranes which occupy them
from neighbouring bones, thus completing the
angles of the bones and forming the sutures.
The closure, especially of the posterior and
lateral, is further assisted by the frequent
development of Wormian bones in these situa-
tions. All traces of these unossified spaces
disappear before the age of four years.

The temporal bone in respect of its state of ossification in the later stages
of foetal life, consists of three pieces, the squamo-zygomatic, petro-mastoid,
and tympanic. The squamo-zygomatic is ossified from a single nucleus,
which appears in the lower part of the squamosal about the seventh or eighth

Fig. 59.—Smparate Parts oF THE TeExPoRAL Bone Fig. 59.
oF A CHILD AT Brrtx (R. Quain).

a@, squamo-zygomatic; 6, the tympanic bone,
forming an imperfect ring, open superiorly ; c, the
petro-mastoid part ; ¢ being placed on the mastoid
part : part of the cavity shown in shade is the
tympanum.

week. From this point ossification extends
upwards into the squamosal, and outwards into
the zygoma. During the third month an osseous
nucleus appears in the lower part of the external
membranous wall of the tympanum, and
extends upwards as a slender arch, forming
the tympanic ring, an imperfect circle, open
superiorly, and which encloses the tympanic
membrane. Before birth the extremities of this
ring become united with the squamo-zygomatic.
Petro-mastoid or periotic. The ossification of this part of the temporal bone
does not begin so soon as that of the other parts. It is only towards the end of
the fifth month and in the course of the sixth (according to Kolliker and Huxley)
that the bony parts of the internal ear begin to appear in the cartilage which
precedes them. These parts arise, at least in the case of the labyrinth, from
numerous minute bony deposits; some, however, soon coalescing. The first
osseous nuclei appear at the end of the fifth month on the anterior surface of
the petro-mastoid over the cochlea, and shortly afterwards one or two nuclei
appear on the posterior surface in connection with the formation of the semi-
circular canals. These different nuclei soon unite, and ossification extends out-
wards into the mastoid portion. According to Huxley the principal ossifie centres
come to be disposed so as to form three portions, which may be distinguished
by the following names applied to them respectively by him, viz.: 1, Preotic,
including most of the labyrinth and upper part of the petrous bone, together
with part of the mastoid; 2, Opistotic, comprehending mainly the lower part of | __
the petrous bone, with the fenestra rotunda and half of the fenestra ovalis ; Yieiarien
and 3, Epiotic, corresponding to the lower part of the mastoid.
At birth the petro-mastoid is separated from the squamosal by a thin plate of
intervening cartilage, bony union taking place during the first year ; the mastoid
portion also is quite flat, the glenoid fossa shallow, the articular eminence scarcely

70 BONES OF THE HEAD.

to be seen, and the styloid process cartilaginous. After birth the external’
auditory meatus is gradually formed, superiorly by the arching outwards of the
united squamous and petro-mastoid portions, and inferiorly and laterally by the
development of the tympanic plate, a lamina developed from the outer surface of
the tympanic ring, and which becomes united behind with the petro-mastoid, but
is separated in front by the fissure of Glaser from the squamosal. The mastoid
process is developed about the second year, but air-cells are not formed till near
puberty. About puberty also ossification begins in the styloid process, but osseous
union with the temporal only takes place in adult life.

The sphenoid bone presents in infancy traces of a natural division into a
posterior or postsphenoid part, to which the sella turcica and great wings belong,
and an anterior or presphenoid part, to which belong the body in front of the
olivary process and the small wings,—a division which is found in many animals.
complete and persistent through life. The first osseous nuclei of the postsphe-
noid division appear about the eighth week in the great wings, one on each side,
between the foramen rotundum and foramen ovale, and spread thence outwards.
into the wing and downwards into the external pterygoid process. About the
same time also two granules appear in the postsphenoid part of the body, placed
side by side in the sella turcica; these unite about the fourth month, and after
their union two others appear, from which are formed the lingulz, inside which
are placed the carotid grooves. The internal pterygoid processes, corresponding
to the pterygoid bones of animals, are ossified from distinct nuclei, which appear
in the fourth month; they unite with the external pterygoid processes in the
fifth or sixth month,

Fig. 60.—OsstFIcATIon oF THE SpHENOID Bone (R. Quain).

A, sphenoid bone from a feetus of three months, seen from above ; 1, 1’, the greater
wings ossified ; 2, 2’, the lesser wings, in which the ossification has encircled the optic
foramen, and a small suture is distinguishable at its posterior and inner side; 3, two
round granules of bones in the body below the sella turcica, the rest being cartilaginous.

B, copied from Meckel (Archiv, vol. i. tab. vi. fig. 23), and stated to be from a feetus
of six months ; 2*, additional nuclei for the lesser wings ; 5, separate lateral processes
of the body : the other indications are the same as in A.

C, sketch of the back part of the bone shown in A ; 4, the internal pterygoid processes
still separate.

D, the sphenoid at the usual period of birth. The great wings are still separate. The
anterior sphenoid is now joined to the body, and the internal pterygoid processes (not
seen in the figure) are united to the external.

The great wings are united to the body in the first year. In the presphenoid
division the first pair of nuclei appear in the eighth or ninth week outside the:
optic foramina, and extend by their growth into the small wings: another pair
of granules appear on the inner sides of the foramina, and the presphenoid por-

OSSIFICATION OF THE UPPER JAW. 71

tion of the body either results from the union of these, or is an independent
growth. The presphenoid is united to the body of the postsphenoid from the
seventh to the eighth month. The line of union is indicated for some time by a
hole filled with cartilage, round above, and opening inferiorly into a wide notch,
which is recognisable for several years after birth. The body of the presphenoid
is for a year or two broad and rounded inferiorly, but becomes gradually narrower
and more prominent : it is separated at first by a layer of fibro-cartilage from the
sphenoidal spongy bones.

The sphenoidal spongy bones seldom appear till after birth, and are united to
the body at the age of puberty. Each is in early life a hollow pyramid formed
by the union of three separate laminz, viz., an inferior, an external, and a
superior : the inferior lamina forms the greater part of what can be distinguished
in the adult; the external is that to which the orbital portion belongs; while
the superior lamina, forming the inner wall and roof of the original sphenoidal
sinus, becomes, as the sinus expands, partly absorbed and partly united to the
attenuated body of the pre-sphenoid, which is ultimately reduced to the thin
septum sphenoidale and the rostrum.

In the ethmoid bone ossification commences in the fourth or fifth month, by
the appearance of a nucleus in the orbital plates of the lateral masses gradually
extending into the turbinated bones. During the first year the vertical and
cribriform plates are ossified from a single nucleus, which, spreading outwards,
unites with the lateral masses about the beginning of the second year. The
ethmoidal cells are not formed till the fourth or fifth year.

The superior maxillary commences to ossify immediately after the lower
maxilla and the clavicle from several nuclei, the earliest of which appears in the

Fig. 61.

Fig. 61.—DirrerENtT VIEWS oF THE Superior MaxiniAry Bone oF A Fa@rvs or Four
OR FIVE MonTHs (R. Quain).

A, external surface; a fissure, 1, is seen extending through the orbit into the infra-
orbital foramen.

B, the internal surface ; the incisor fissure, 2, extends from the foramen upwards
through the horizontal plate and some way into the nasal process.

C, the bone from below, showing the imperfect alveoli and the incisor fissure, 2’, 1,
which crosses the palatine plate, between the second and third alveolus, and passes through
the outer part of the bone.

alveolar arch about the sixth or seventh week. Its early growth has not yet been
sufficiently studied. Béclard (Meckel’s Archiv, vi. p. 432) states that it consists
at first of five pieces, viz. : 1, an alveolar arch; 2, a palatal part ; 3, an orbital and
malar; 4, a nasal and facial ; 5, an incisor part. This, however, does not appear
to be a constant arrangement. By the end of the third month these pieces have
united together ; at the same time two ridges are seen prolonged downwards from
the lower surface of the alveolar arch, forming the dental groove. Before birth
this groove is divided into alveoli by partitions which arise from its floor. The
antrum begins as a shallow depression, formed before birth on the inner surface
of the bone. This deepens and extends outwards, gradually separating the orbital
and palate portions of the bone, which at birth are very close together.

In all young subjects, and sometimes even in the adult, there is a fissure—
the incisor sissurc—passing outwards from the incisor foramen to the alveolar

72 BONES OF THE HEAD.

border, in front of the canine socket. The part in front of this fissure—namely,
that which bears the incisor teeth—forms in all mammals except man a separate
bone, the intermawillary or premawillary ; and anatomists have therefore sought
with great care for proofs of its original independence in the human subject,
but it does not appear that even in the earliest stages of development it has
been seen by any one entirely unattached to the rest of the bone, or that its line
of suture has been traced upon the facial surface. On the other hand, in cases
of eompletely cleft palate, the bones supporting the incisor teeth are placed on
a projecting portion of bone corresponding to the premaxillary, which is articu-
lated to the fore part of the vomer, and is entirely detached from the superior
maxillary bones.

The palate bone is ossified from a single centre, which appears in the seventh
or eighth week at the angle between its horizontal and ascending parts.

The vomer jis ossified from a single nucleus appearing at the upper part about
the eighth week. From this nucleus two laminz are developed, which, passing down

Fig. 62. Fig. 62.—TuEe Foran Vomnsr NEAR THE TIME OF DirtTH
(R. Quain).

1 & 2 show the two plates of which the bone consists, and
which are united behind and below.

on either side of the middle line, embrace the septal car-
tilage. These laminz gradually undergo increased union
from behind forwards till the age of puberty, thus forming a mesial plate, with
only a groove remaining on its anterior and superior margins.

The nasal and lachrymal bones are each ossified from a single centre, which
appears about the eighth week.

The malar bone has been generally described as being ossified from a single
nucleus, but more recently it has been observed to be double in the human fcetus
of two months, and it remains composed of two parts in some quadrumana
through life. (Canestrini in Ann. d. Soc. d. Natur. in Modena, 1867 ; Darwin, on
the Descent of Man, vol. i. p. 124.)

The inferior turbinated bone is ossified from a single centre, which only
appears in the fifth month.

The inferior maxilla begins to ossify before any other bone except the
clavicle. It consists of two similar lateral parts, which are still separate at birth.

Fig. 63. Fig. 63.—Tur Inrerron MAXILLA OF A
CuiLp at bBrrru (R. Quain).

a & b indicate the two portions separate at
the symphysis.

The ossific matter is at first deposited
in fibrous tissue, surrounding the carti-
lage of Meckel externally, and at a later
period cartilage participates in the ossifi-
cation. Some observers admit only a
single ossifie centre for each side (Nes-
bitt and Meckel) ; while, according to others, in addition to the main piece there
are separate nuclei for the corenoid process, the condyle, the angle, and the inner
side of the alveolus (Spix), or only for some of these parts (Kerckringius,
Béclard, Cruveilhier). The dental canal is at first a simple open groove ; but by
a gradually deepening, and by the growth of a thin lamina of bone upon the
inner side of the body of the jaw, it is converted into a channel at the bottom
of the dental groove. This lamina also forms the inner wall of the dental groove,
in which, as in the upper jaw, the alveoli are formed by the subsequent growth
of partitions. At birth the coronoid process is large, the neck of the condyle
short and bent backwards, the ramus also very short and oblique, the angle at

MORPHOLOGY OF THE SKULL. 73

which it joins the body of the jaw being about 150°. During the first year
osseous union takes place at the symphysis between the segments of the jaw.
In this and subsequent years the body becomes deeper, thicker, and longer, the
ramus and the neck of the condyle lengthen, and the angle at which the ramus
joins the body becomes less obtuse, till in the adult it is nearly a right angle.
Tn old age, consequent upon the loss of the teeth and the absorption of the alveolar
margin, the body becomes shallower, and the angle is again increased.

The hyoid bone has five points of ossification—one for the body, and one for
each of its great and small cornua. The ossification begins in the great cornua
and body in the last month of foetal life. Ossification of the small cornua
begins in the first year, but osseous union with the body only occurs after middle
life. The stylo-hyoid ligaments are occasionally ossified in some part of their

extent,
GENERAL MORPHOLOGY OF THE BONES OF THE HEAD.

The circumstances which contribute most to modify the form of the human
skull and the condition of its component bones, as compared with that of
animals, are—Ilst, the proportionally large size of the brain and the corresponding
expansion of the cranial bones which enclose it; 2nd, the smaller development
of the face as a whole, and especially of the jaws, which brings the facial bones
almost entirely under the fore part of the brain-case, instead of in front of it, as
-occurs in all animals, with the partial exception of the anthropoid apes; and 3rd,
the adaptation of the human skeleton to the erect posture, which, as regards
the head, is attended with the sudden bend of the basicranial axis at a consider-
-able angle upon the line of the erect vertebral column ; and along with this the
advance of the occipito-vertebral articulation to such an extent as to make the
head nearly balanced on the upper extremity of the spine. The downward openings
-of the nostrils, the forward aspect of the orbits and eyes, the nearly vertical fore-
head, and more or less oval-shaped face, are accompaniments of these human
peculiarities in the form of the head. which, together with those already men-
tioned, strongly contrast with the smaller cranium and its strong crests of bone,
the larger projecting face and jaws, and the other characteristic features of the
skull in most animals.

As regards the condition of the individual bones, it is further to be remarked
that there is generally in the human skull a more complete consolidation or bony
union of the osseous elements than in animals, so that the whole number of
bones forming the cranium and face is least in man, Thus, to mention only
some of the most marked examples of this difference among mammals; the
frontal bone and the lower jaw frequently divided into two lateral portions ; the
premaxillary very generally a separate bone from the maxillary ; the presphenoid
in many separate from the postsphenoid; the interparietal from the occipital ;
the reduction in size of the squamosal, and its occasional separation from the
petrous ; the increase in the proportions of the tympanic portion or bulla; and
the very frequent development of bony elements connecting the hyoid bone
directly with the skull. It is also worthy of observation that some of the conditions
now referred to as permanent in animals exist as transitory stages of develop-
ment in the feetus of man.

Homologies.—It would be out of place in this work to enter at any length
into the consideration of the homologies of the bones of the human skull,—a
subject which would require a minute reference to embryology and a wide range
of comparative anatomy. But as it may be useful at least to show the bearing of
such homological views on human anatomy, there has been introduced here a dia-
grammatic figure of the bones of the fcetal head (see fig. 64) and a table of their
nomenclature, in which an attempt is made to indicate the morphological relations
of the several bones to each other and to those of quadrupeds, and an explanation
is given of the signification of some of the terms applied by comparative ana-
tomists to these bones in connection with the names usually given to them in
works on human anatomy. For fuller information on this subject the reader is
referred to the works of Owen, Goodsir, Huxley, Flower, St. George Mivart, and
others already quoted.

74 BONES OF THE HEAD.

CLASSIFIED LIST OF THE BONES OF THE HEAD AND THEIR
TYPICAL COMPONENT PARTS *:—

1. BONES FORMING THE CRANIO-FACIAL AXIS.

Mesethmoid; Vertical plate of the ethmoid bone, including the cartilaginous
nasal septum, which is partially enclosed by
Vomeric; The Vomer.
Presphenoid; Anterior part of the body of the sphenoid bone.
Basisphenoid; Posterior part of the body of the sphenoid bone, including the
sella turcica.
Basioccipital; Basilar process of the occipital bone.

2. UPPER OR NEURAL ARCHES, FORMING LATHRAL AND UPPER WALLS
OF THE CRANIAL CAVITY.

Nasals; The nasal bones.
Orbito-sphenoids ; The lesser wings of the sphenoid bone.
Frontals; United in the single frontal.
eee Great wings of the sphenoid bone with the external pterygoid.
plates.
Parietals ; The parietal bones.
Exoccipitals; Condyloid portions of the occipital bone.
Supraoccipital ; Tabular part.
Interparietal, of some animals, corresponds to the upper part of the foregoing.
The temporal bones interposed between the occipitals and sphenoids consist of
Periotics, or petro-mastoid bones ; The petrous and mastoid portions of the tem-
poral bone ; the first including the labyrinth and meatus auditorius internus.
Squamosals, or squamo-zygomatic; The squamous part of the temporat
bone with the zygoma, including the articular surface of the lower jaw.
Tympanics; The tympanic ring and auditory process with the postglenoid
part of the temporal bone.

3. LOWER OR VISCERAL ARCHES COMPLETING THE FACE AND
ENCLOSING THE NOSE, MOUTH, AND PHARYNX.

Ethmo-turbinals; The lateral masses with the upper and lower turbinated.
bones of the ethmoid, and the cribriform plates.

Lachrymals; The lachrymal bones.

Maxillo-turbinals ; The inferior turbinated bones.

Premaxillary, or intermaxillary ; The incisor part of the superior maxillary
bones.

Pterygoids ; The internal pterygoid plates.

Palatals; The palate bones.

Maxille; The superior maxillary bones, excepting the incisor part.

Malars; The malar bones.

Malleus, Incus, and Stapes; The ossicula auditus or malleus, incus, and
stapes.

Mandibles ; United in the inferior maxilla or lower jaw.

StyIo-hyals with Tympano-hyals (of Flower); The styloid process of the
temporal bone.

Epi-hyals; The stylo-hyoid ligaments.

Cerato-hyals; The upper or lesser cornua of the hyoid bone.

Basi-hyals; The body of the hyoid bone.

Thyro-hyals; The great cornua of the hyoid bone.

Branchial Arches; These follow the preceding, but are only temporary foetal
structures in man and all vertebrate animals, except amphibia and fishes.

* The names first given, and printed in block type, are those received in comparative:
anatomy ; those usually employed in human anatomy follow, and are printed in common
y > ~ ~ ?
type.

HOMOLOGIES OF THE BONES OF THE HEAD. 7

vr

The general correspondence between the bones of the head in man and animals,
implied in the names given to them in the foregoing table, is so well ascertained,
and, in most instances, so obvious, that it is unnecessary to say more than that
it is very generally acknowledged by comparative anatomists, and that it is chiefly

Fig. 64.

4
?,

\”

A
i
n

Fig. 64.—DrAGRAMMATIC VIEW OF THE BoNES IN THE RIGHT HALF oF A Faeran
SKULL FROM THE INSIDE. (A. T.)

In this figure the bones have been slightly separated and displaced so as to bring the
whole into one view: f, frontal ; pa, parietal ; so, supra-occipital ; nm, nasal ; /, lachry-
mal ; ma, malar ; 0s, orbito-sphenoid ; as, ali-sphenoid ; sg, squamosal ; zy, zygomatic ;
per, petro-mastoid ; eo, exoccipital ; et, ethmoturbinal ; mx, maxilla ; mt, maxillo-
turbinal ; pm, premaxillary ; me, mesethmoid ; v, vomer; pl, palatal; pt, pterygoid ;
ps, presphenoid ; bs, basisphenoid ; bo, basioccipital ; ¢e, bodies of 2nd, 3rd, and 4th
cervical vertebree ; c’, odontoid process; «, anterior arch of atlas; s, spinous process of
Ist, 2nd, 3rd, and 4th cervical vertebre ; cm, neural or medullary canal ; ch, a line in-
dicating the position of the notochord passing through the vertebral bodies into base of
the cranium, bs; ty, tympanic ring, along with m/, 2, and st, displaced from its connection
with per ; ml, malleus ; c,mk, cartilage of Meckel ; mn, lower jaw or mandible ; 2, incus ;
st, stapes ; sth, stylo-hyal ; ch, cerato-hyal (lesser cornu); th, thyro-hyal (greater cornu) ;
bh, basi-hyal (body of hyoid).

on some points connected with the earliest condition, and the homological com-
parison of a few of the bones, that differences of opinion continue to exist.
Besides the general evidence in fayour of the homologies of these bones which
has been drawn from the study of their form, position and connections, strong
confirmation of these views is also obtained from their relations to other organs.
Among these, from the remarkable constancy of their relations, the passage of the
nerves out of the cranium is one of the most important. Thus, the nerves.

76 BONES OF THE HEAD.

belonging to the principal organs of the senses pass into their sense capsules as
follows, viz.: a, the olfactory through the cribriform plate developed in connection
with the ethmo-turbinal; 0}, the optic through the inner part of the orbito-sphe-
noid ; ¢, the auditory directly into the periotic; d, the motor nerves of the eye-
ball and its muscles, with the ophthalmic division of the trifacial, between the
orbito-sphenoid and ali-sphenoid ; ¢, the second and third divisions of the trifacial
through the inner part of the ali-sphenoid ; /, the facial by its descending division
through the meatus internus, the so-called aqueduct of Fallopius and the stylo-
mastoid foramen, and by the Vidian nerve, through the pterygoid foramen; g,
the glosso-pharyngeal, pneumogastric, and spinal-accessory nerves between the
petrosal and exoccipital ; and the hypoglossal nerve through the condylar fora-
men of the exoccipital. The internal carotid artery, it may be further stated,
enters the cranium by a canal separated from the foramen lacerum medium or
space between the petrous, basi-occipital, and basi-sphenoid ; and the jugular vein
issues by the fore part of the foramen lacerum posterius.

A general review of the relations of the bones of the head leads to the conclu-
sion that they may be looked upon as consisting mainly of three sets of parts,
viz.: Ist, Basal or central parts, forming a series prolonged forwards in the
line of the vertebral axis, and constituting a cranio-facial axis; 2nd, Lateral
superior arches, enclosing the brain or much-expanded medullary centre; and
3rd, Lateral inferior arches, enclosing, in part at least, the visceral cavity as
represented by the nose, mouth, and pharynx. ‘Together with the foregoing
are associated two other sets of elements, viz., Ist, the Sense capsules or
cavities, which are interposed between other bones, and are connected with the
lodgment of the higher organs of sense, the nose, eye, and ear; and in the
case of the nose, but more especially of the ear, the capsules are formed of
special and complex bony apparatus; and 2nd, Superadded or investing bones,
which are extraneous to the more fundamental osseous elements.

Vertebrate theory of the skull.—It is mainly this relation of a superior
neural arch and an inferior visceral arch to parts of the skull which are central
or basicranial, notwithstanding the great expansion of the one and the limited
nature of the other, which has made it a favourite view of many anatomists to
compare the plan of construction of the skull to that of a series of vertebre,
from the time when the idea of a vertebrate theory of the skull first occurred to
Goethe in 1791, and was subsequently, though independently, conceived and
worked out by Oken, and first published by him in 1807. This theory, however,
has undergone various modifications in the hands of the successive comparative
anatomists by whom it has been supported; while others of distinction have
refused to admit the validity of the grounds on which it has been framed. More
recent researches, and especially those of W. K. Parker, have thrown much new
light on the subject.

The osseous segments which have hitherto been most frequently regarded by
anatomists as representing central vertebral elements in the head correspond with
the four basicranial bones distinguished in the preceding table, viz., the occipital,
basisphenoid, presphenoid, and mesethmoid ; the vomer being merely an investment
of the last. The uppér or neural arches connected respectively with these as
centra are as follows, viz., with the first or basioccipital, the exoccipital and
supraoccipital surrounding the foramen magnum, and in which few refuse to
recognise something of the vertebral character ; 2nd, with the basisphenoid, the
alisphenoid and parietal, to which the temporal seems also to contribute a part ;
3rd, with the presphenoid, the orbito-sphenoid and frontal ; and 4th, with the
mesethmoid, also the frontal and the nasal, if the latter bone be included in the
number of superior arches. The lower or visceral arches are less easily referred
to their respective centra, But if, leaving aside the more precise determination
of their morphological relations which may result from a full study of embryo-
logy, we regard chiefly their form and connections after the bones have attained
their osseous condition, the following elements may be enumerated in an order
from before backwards, including the investing or superimposed bones along
with those of the arches, viz.: Ist, the premaxillary ; 2nd, the pterygo- -maxil-
lary, including the palate; 3rd, the mandibular, including the cartilage
of Meckel and the malleus : 5 4th, the upper or cerato-hyoid, including the incus

VARIOUS FORMS OF THE SKULL. iid
end*stapes (according to Huxley and Parker) ; and 5th, the lower or thyro-hyoid ;
following which, 6th, &c., are the branchial plates, which, though never attaining
even the cartilaginous condition in the foetus of man and the higher animals,
yet give indications of the tendency to the continuation backwards of visceral
arches in the region between the head and the trunk.

The origin of the walls of the cranial cavity from the same embryonic elements
as the vertebrze, and the prolongation of the notochord of the embryo into the
substance of the basioccipital and part of the basisphenoid bones, are of themselves
strong arguments in support of the central character of these two osseous elements.
But, on the other hand, it is to be remarked that the notochord does not reach the
region of the sella turcica, but is directed towards the dorsum sellz, and thus
leaves a part of the basisphenoid and the whole of the presphenoid and meseth-
moid unoccupied by any true central or vertebral axis. And according to Parker's
views the last-named parts, arising in the trabeculz cranii, are originally double,
and only secondarily become mesial and single. Further, it is contended that there
is not, as occurs throughout the whole of the vertebral column, any primary divi-
sion of the formative cartilage marking out four or even two of these centres of
the basis of the skull, and it is only after ossification has begun separately in
each that the divisions between them become apparent.

The similarity of construction, then, implied in the vertebrate theory of the
skull belongs chiefly to the region of the occipital bone ; and while it may be
admitted that in other parts of the skull further forward there are circumstances
of correspondence with the vertebrate plan, yet in these there are also differences,
and we must therefore await the fuller and more certain determination of several
homological points, at present involved in doubt, before any general theory of
cranial morphology worthy of general adoption can be framed. (See especially
W. K. Parker's paper on the ‘“‘ Structure and Development of the Skull in the
Pig,” Phil. Trans., 1873; and in addition to the works previously referred to,
Cleland, ‘On the Relations of the Vomer,” &c., Trans. Roy. Soc., 1862; Spix,
“ Cephalogenesis,’ 1815 ; Hallman, “ Die Vergleich. Anat. des Schlifenbeins,” 1837.

THE VARIOUS FORMS OF THE SKULL.

I. Differences according to Age.—In the earlier stages of its development
the posterior part of the cranium bears a very large proportion to the anterior
part ; so much so, that inthe second month of feetal life the line of the tentorium
cerebelli is vertical to the basis cranii, and divides the cranial cavity almost

Fig. 65.—Lareran Vinw OF THE Fig. 65.
Cuitp’s Heap at Birra (from
Leishman), 4
This figure shows the peculiarly

elongated form of the skull in the

child, and the small proportion which
the facial bears to the cranial part,
and also the interval left between the
parietal, occipital, and temporal bones
sometimes called lateral fontanelles.

The lines indicate the various dia-

meters.

equally into two parts. The pari-
etal region then increases rapidly
in volume, along with the in-
creased development of the cere-
bral hemispheres ; the frontal
region next augments; and again, in the latter part of foetal life, the occipital
region increases as the cerebrum extends backwards (Cleland). At the time of
birth the parietal region has reached its largest development in proportion to
the occipital and frontal regions. The greatest frontal breadth is then smaller
in proportion to that between the parietal eminences than afterwards. In the

78 BONES OF THE HEAD.

first years of childhood the superior parts of the cranium grow more rapidly than
the base. Thus, in the frontal region, the upper part of the frontal bone grows
more rapidly than its orbital processes, giving the prominent appearance of the
frontal eminences peculiar to children. The face at birth scarcely reaches
an eighth of the bulk of the rest of the head, while in the adult it is at
least a half (Froriep, ‘‘ Characteristik des Kopfes nach dem Entwicklungsgesetz
desselben, 1845”). At the same time that the face increases in bulk, the lower
part of the forehead is brought forward by elongation of the anterior cranial
fossa, and on the approach of adult age, especially in the male, it becomes
still more prominent by the expansion of the frontal sinuses. The face
becomes elongated in the progress of growth, partly by increased height
of the nasal fosse and adjacent air-sinuses, partly by the growth of the teeth
and the enlargement of the alveolar arches of the jaws. In old age the propor-
tion of the face to the cranium is diminished by the loss of the teeth and absorp-
tion of the alveolar portions of the jaws. In consequence of this the upper jaw
retreats, while in the lower jaw the same cause gives, especially when the mouth
is closed, a greater seeming prominence to the chin.

II. Sexual Differences.—The female skull is, in general, smaller, lighter,
and smoother than that of the male; itis less marked by muscular prominences,
and has also the frontal sinus less developed. The face is smaller in proportion
to the cranium, the jaws narrower, and the frontal and occipital regions less
capacious in proportion to the parietal. (Huschke.) The female skull resembles
the young skull more than that of the adult male ; but it must also be admitted
that it is often impossible to determine the sex by the appearance or form of
a skull.

III. National Differences.—That characteristic forms of skull are presented
by the various races of men has probably been long known, but was first dis-
tinctly pointed out by Camper. Subsequently the investigations of Blumenbach
established the connection between the study of these forms and ethnology, which
since his time has been maintained and greatly extended. The extent, nature and
constancy, however, of the ethnical differences of skulls are subjects open to dis-
cussion, But, although many skulls are to be met with which fail-to exhibit the
common characteristics of the race to which they belong, or which present pecu-
liarities similar to those of nations considerably removed from them, yet, it must be
admitted, that there are certain forms of skull highly distinctive of the principal
varieties of mankind, and often even distinguishable in nations inhabiting countries
not far removed from one another. Great differences occur with respect to size in
the skulls of different nations. Among the smallest skulls may be mentioned those
of the Hindoo, the ancient Peruvian, and the Bosjesman ; among the most mas-
sive those of the Scandinavian, the Caffre, and the Maori. Various characters
are found belonging to the skulls of rude tribes, which serve to distinguish them
from those of civilised nations. Among those characters may be mentioned,—a
depressed appearance between the middle line of the calvarium and the temporal
ridges, both of which stand out prominently, making the roof of the skull seem
like a house top ; a greater width of the zygomatic arches, and of the anterior
nares ; greater length and strength of the jaws, together with projection forwards
of the incisors, so that the teeth of the upper meet those of the lower jaw at an
angle, instead of both sets being nearly perpendicular, as in cultivated nations.
Elongation of the face downwards may be regarded as a specially human charac-
teristic connected with the use of voice and speech, but projection of the jaws
forwards is only advantageous for the seizure of food, and gives an appearance
of approach to the still further projected form of the jaws in the lower animals,
particularly when accompanied, as it often is, by deficient development and
receding form of the chin,

The average horizontal circumference of the British male cranium, taken one
inch above the orbits, is about 21 inches, varying however frequently between
20 and 22; the antero-posterior diameter is about 7; inches, and the greatest
transverse (parietal) diameter is about 52 inches. The average height of the
skull from the plane of the foramen magnum to the vertex is about 5} inches.
The average capacity of the well-formed British male cranium may be stated
at from 90 to 95 cubic inches, varying in extremes from about 70 to 120, That

VARIOUS FORMS OF THE SKULL. te)

of the female is from 80 to 90 cubic inches. As contrasting with this more
developed condition may be mentioned the cranial capacity of the Australian,
which averages from 70 to 80 cubic inches, and not unfrequently falls as low as
65 cubic inches. (See on this subject the further details under Size of the Brain.)

Measurement and Classification of Differences.—The estimation of differ-
ences in the form and size of skulls by a simple and accurate method is not easily
accomplished, and their suitable arrangement and nomenclature is still more
difficult.

The method proposed by, Camper, in which the degree of projection of the face
as compared with the cranium is measured by the ‘ “facial angle,” formed by the
meeting of a line descending from the most
projecting part of the forehead in front of
the upper incisor teeth with another carried Fig. 66.
backwards from the anterior nasal spine at
the level of the external auditory meatus,
fails to take cognizance of the size of the
cranium and many important features of
difference, and is subject to various sources
of fallacy from partial variations which do
not affect the whole character of the skull.

The “occipital” angle of Daubenton,
which varies with the direction of the plane
of the foramen magnum of the occipital
bone, is mainly an indication of the attitude
of the head in relation to the vertebral
column. In man this plane looks down-
wards and_forwards, in the anthropoid apes
downwards and backwards, aud in most Fig. 66.—Prognatnous SKULL OF A
quadrupeds nearly directly backwards, so Native Austrauian (Carpenter). 3
as in them to bring the basicranial and the
vertebral axis almost into the same line.

The method of Blumenbach by the “ norma verticalis,” or perpendicular view
from above, when combined with measurements, gives important information as
to the size and form of the cranium, and the extent to which the zygomatic
arches and jaws project beyond or are concealed by the cranial walls, and when
combined with the lateral and front views of the head, as in the estimations of
Pritchard, may give sufficiently clear views of the form of the cranium and face,
their more or less oval form, and the degree of orthognathism or prognathism.

The more recent classification of skulls by Retzius, in which cranial form and
facial relation are both taken into account, is at once simple and comprehensive.
In this system all those skulls in which the transverse diameter of the cranium
bears to the longitudinal the proportion of 80 pe per cent. or above it are ranked as
Brachycephalic, wide or short skulls, and those in which the proportion is lower
than 80 per cent. are placed in the Dolichocephalic group, narrow or long skulls ;
‘and under each of these primary divisions is established a subordinate one
founded on the relation of the face to the cranium, under the names of the
orthognathous and prognathous forms. Thus, the usual British skull and that
of the natives of Western Europe belong to the orthognathous dolichocephalic
type ; the African negro and Australian to the prognathous dolichocephalic; the
Sclayonic nations are examples of the orthognathous brachycephalic, and the
Mongolians of the prognathous brachycephalic type.

For an approximate determination of the form and size of skulls it may be
sufficient to ascertain the principal dimensions by external measurements in the
horizontal, transverse and vertical diameters of the cranium, and in the vertical
and transverse diameters of the face, and to measure the capacity of the cranium
by means of suitable material introduced into its cavity: and it will add greatly
to the value of these measurements if other dimensions are ascertained by mea-
surements between different fixed points of the skull.

But for the full description of all the varieties which occur, and the minuter
appreciation of the relations of the several parts,a more elaborate system of
measurement must be carried out. Considerable attention has in recent times

80 BONES OF THE HEAD.

been given to this subject, on the Continent by Carus, V. Baer, R. Wagner,
Virchow, Welcher, Huschke, Luce and others, and in this country by Busk,
Huxley, Cleland, and Barnard Davies. From the researches of these authors the
general conclusion may be drawn, that external measurements alone are insuffi-
cient to supply all the information required as to the form and relations of the
parts of the skull, and that it is necessary to combine with them numerous
measurements which can only be made in the skull opened by a mesial vertical
section, ‘The observations of Virchow, Huxley, and Cleland have also shown the

Fig. 68.

Fig. 67.—SkuLL or EvROPEAN TENDING TOWARDS THE BRACHYCEPHALIC For«
(Carpenter), 3

Fig. 68.—Stronety DonrcHocerHatic Skutn or Evropran (Carpenter). 4

importance which is to be attached to the relations of the basi-cranial axis as a
very uniform standard of reference for comparing the direction and dimensions of
other parts. Without going into farther detail here, it may be mentioned that
the angle formed by the basicranial axis with the line of the cribrethmoid plate,
the “‘ ethmo-cranial” angle of Huxley, and nearly the “ saddle-angle” of Virchow,
is about 140° in British and Western European skulls, diminishing in the highest
forms, and opening out in the lower, till in quadrupeds the two lines run almost
into one; and that the “‘ premaxillary” angle of Huxley, between the anterior
extremity of the basicranial axis and the front of the incisor ridge of the upper
jaw, gives a reliable estimate of the degree of facial projection; varying in diffe-
rent skulls from 83° to 110°, so that the angle above 95° is indicative of progna-
thism, below it of orthognathism. (On the foregoing subject consult, in addition
to the works of Camper, Cuvier, Blumenbach, Lawrence, Carpenter, and other
authors quoted, the following : viz., Transl. of the Memoir of Retzius in the Brit.
and For. Med. Chir. Review, 1860; Owen, in Trans. Zool. Soc., vol. iv., 1851 ;
Busk’s papers in Trans. Ethnol. Soc. Lond., vol. i., 1861, and Journ. of Anthrop.
Inst., vol. iii.; Huxley’s Lect. ‘‘Man’s Place in Nature,” and in Journ. of Anat.
and Physiol., vols. i. and ii.; Thurnam and Davies, “Crania Britannica,” and
Davies, ‘‘ Thesaurus Craniorum,” 1867 ; Cleland’s Memoir in Philos. Trans., 1869 ;
as also Virchow, in his work on the‘‘ Development of the Cranial Basis,” 1857, and
in Germ. Quart. Mag., Nov. 1871; Huschke, Schiidel, Hirn, and Seele, &c., 1854;
and Lucae, Zur Morphol. der Rassenschiidel, 1861-64.)

IV. Irregularities of Form.—The most frequent irregularity in the form of the
skull is want of symmetry. This sometimes occurs in a marked degree, and there
is probably no skull perfectly symmetrical. The condition which has been ob-
served to co-exist most frequently with irregular forms of skull is synostosis, or
premature obliteration of certain of the sutures. The cranial bones increase in
size principally at their margins; and when a suture is prematurely obliterated
the growth of the skull in the direction at right angles to the line of suture may
be supposed to be checked, and increased growth in other directions may take
place to supply the defect: but this condition is not constant (see Huxley,
loc. cit. ; Virchow, ‘‘Gesammelte Abhandlungen,”’ 1856; J. Barnard Davies,

BONES OF THE UPPER LIMB. 8i

“On Synostotic Crania,’ 1865; W. Turner, ‘On Cranial Deformities,’ in Nat.
Hist. Review, 1864.) Another series of irregular forms of skull is that produced
by pressure artificially applied in early life, and is best exemplified from among
those American tribes who compress the heads of their children by means of an
apparatus of boards and bandages : it is also illustrated in a slighter degree by
individual instances in which undue pressure has been employed unintentionally.
(Gosse, “ Essai sur les Déformations artificielles du Crane,’ 1855.) Posthumous
distortions likewise occur in long-buried skulls, subjected to the combined
influence of pressure and moisture. (Wilson, “ Prehistoric Annals of Scotland.”)

IV.—BONES OF THE UPPER LIMB.

The upper limb consists of the shoulder, the arm, brachium, the
forearm, antibrachium, and the hand, manus. The bones of the
shoulder are the scapula and clavicle, which together form the pectoral
arch or shoulder girdle ; in the arm is the humerus ; in the forearm
are the radius and ulna; and in the hand three groups of bones, the
carpus, metacarpus, and digital phalanges.

SCAPULA,

This bone is placed upon the upper and back part of the thorax,
occupies the space from the second to the seventh rib, and forms the
posterior part of the shoulder-girdle. It is not attached directly to
the trunk, but is articulated with the outer end of the clavicle, and
from it is suspended the humerus in the shoulder-joint.

It is an irregular flat bone of a triangular form, its surfaces are
anterior and posterior, its borders superior, internal, and external, and
its angles superior, inferior, and external.

The anterior surface presents a shallow concavity, the fossa subscapu-
laris or venter, occupied by the subscapularis muscle, and marked by
esdarprominent lines converging upwards and outwards, which give
attachment to the tendinous intersections of that muscle. Separated
from this concavity, there are several smaller flat spaces; one is a
triangular surface in front of the superior angle, another is a smaller
surface at the inferior angle, and these, together with a rough line
running close to the-pestertor border and uniting them, give attach-
ment to the serratus magnus muscle.

The posterior surface or dorsum is divided by the spine into two
unequal parts, the superior and smaller of which is called fossa supra--
spinata, the inferior fossa infraspinata. The supraspinous fossa is
occupied by the supraspinatus muscle. The infraspinous fossa, much
larger than the preceding, presents in the middle a convexity cor-
responding to the concavity of the venter, and outside this a con-
cavity bounded by the prominent external border. It is marked near
the inner border*by short lines, corresponding to tendinous septa of the
infraspinatus muscle, and is occupied by that muscle in the greater
part of its extent. Adjacent to the external border, in its middle third,
is a narrow interval giving attachment to the teres pe and
beneath this, extending over the inferior angle, is a raised oval surface,
from which the teres major arises. These spaces are separated from
that of the infraspinatus muscle by a rough line, which gives attach-
ment to an aponeurotic septum.

VOL, Ie G

io 2)
ho

BONES OF THE UPPER LIMB.

The spine of the scapula is a massive plate of bone projecting back-
wards from the dorsum, and curving slightly upwards. It extends
outwards and a little upwards from the internal border near its upper

Fig. 69 a. Fig. 69 8.

ee f ih CEN
st a BS
= ull \ yi
\ Ny," iX})
ye I, A
! (

Wye,
\\

> he

Fig. 69 a.—Riant Scaputa From sentnp. (A. T.) 3

1, glenoid head ; 2, superior angle ; 3, inferior angle; 4, spine; 4, at the base,
triangular smooth surface of the spine ; 5, acromion ; 6, coracoid process ; 7, supra-
spinous fossa: 7’, infraspinous fossa; 1 to 2, superior border ; 2 to 3, posterivr border
or base ; 1 to 3, external or inferior border ; 10, is opposite the oval surface of origin of
the teres major muscle ; 11, the oblique groove where the teres minor muscle rises ; 12,
the rough ridge where the long head of ne triceps rises ; 13, supra-scapular notch ; 14,
is below the great scapular notch.

Fig. 69 6.—Ricut Scapuna FRom BEForE. (A. T.) 34

1, 5, 6, and 13, as in fig. 69; 5’ articular facet on the acromion for the clavicle:
’ ’ ’ i ’ to} t) 2 >
8, subscapular fossa ; 9, long, narrow surface, and 9’, triangular rough surface, separated
, a tele spy ate ’ ’ s & ’
from the subscapular fossa and giving attachment to the upper and lower parts of the
serratus magnus muscle.

fourth, towards the middle of the neck of the scapula, and becoming
ovadually elevated towards its external extremity, it turns forwards and
is continued into the acromion process. The upper and lower sur-
faces are smooth, concave, of a triangular form, and form part respec-
tively of the supra-spinous and infra- spinous fossee. It presents two
unattached borders, the most prominent of which is subcutaneous and
arises from the internal border of the bone by a smooth, flat, triangular
surface, over which the tendon of the inferior part of the trapezius
muscle’ glides, as it passes to be inserted into a rough thickening
beyond. In the rest of its extent this border is rough, broad, and
serpentine, giving attachment by its superior margin to ; the trapezius,
and by its inferior to the deltoid muscle. ‘The ‘anterior or external
border, short, smooth, and concave, arises near the neck of the scapula,
and is continuous with the under surface of the acromion, surrounding
thus the great scapular noich between the spine and the neck of the
bone.

THE SCAPULA, $3

The acromion process, projecting outwards and forwards from the
extremity of the spine over the glenoid cavity, forms the summit of
the shoulder. It is an expanded process, compressed from above down-
wards. Its superior surface, rough and subcutaneous, is continuous
with the prominent border of the spine ; its inferior surface, smooth
and concave, is continuous with the superior surface and external
border of the spine. On its internal border anteriorly is a narrow
oval surface for articulation with the clavicle.

most, and gently incurved in front. Its rim is flattened, and in the
recent state, it is covered by a fibrous band, the glenoid ligament,
which deepens its concavity ; at its upper extremity is a slight rough-
ness, marking the attachment of the long head of the biceps muscle.

The neck, supporting the glenoid cavity, is most distinct posteriorly,
where it forms with the spine the great scapular notch or groove, leading
from the supraspinous to the infraspinous fossa. The line of the neck,
as described by anatomists, passes superiorly between the glenoid
cavity and the coracoid process, but that of the part described as neck
by surgeons passes internal to the coracoid process.

The coracoid process, thick, strong, and hook-like, rises for a short
distance almost vertically from the superior border of the bone, above
the glenoid cavity, and then bending at a right angle, is directed
forwards and outwards. Its superior surface, towards the base, is
rough and uneven, giving origin to the coraco-clavicular ligaments ;
on its outer border is attached the coraco-acromial ligament, at its
and on the inner edge the pectoralis minor.

The borders or coste of the scapula are three in number. The
superior border is the shortest ; it extends from the superior angle
outwards and downwards to the coracoid process, at the base of which
it presents a rounded suprascapular notch, which is converted into a
foramen by a ligament or occasionally by a spiculum of bone, and is
traversed by the suprascapular nerve. The eaternal, axillary, or inferior
border presents at its upper part, beneath the glenoid cavity, a rough
ridge, above an inch long, to which the long head of the triceps muscle
is attached: below this there is usually a slight groove, where the
dorsal branch of the subscapular artery passes backwards: and at its lower
extremity the border is thick, and rounded over into the space from
which the teres major muscle arises. The internal or posterior border,
called also the base, is the longest of the three, and is divisible into
three parts, viz., a short one opposite the triangular surface of origin
of the prominent border of the spine, and the portions above and below
that space, both of which incline outwards as they recede from the
spine. The upper part gives attachment to the levator anguli scapule
muscle, the middle to the rhomboideus minor, and the lower to the
rhomboideus major muscle. ;:

coracoid and acromion processes, the prominent border of the spine,
and the part near the inferior angle, derive their greater thickness and
strength from increased thickness of the compact bony substance in

some parts, and from cancellated tissue in others, A vascular foramen
G2

o4 . BONES OF THE UPPER LIMB.

usually pierces the inferior surface of the spine, and others are to be
found on the anterior surface of the bone, near the neck.

THE CLAVICLE.

The clavicle or collar-bone extends transversely outwards, with an
inclination backwards, from the summit of the sternum to the acro-
mion process of the scapula, and connects the upper limb with the
trunk.

It is curved somewhat like an italic /: the convexity of the internal
curve is directed forwards, and extends over two-thirds of the length
of the bone ; that of the outer curve looks backwards, and is most
marked near the outer fourth of the bone.

The clavicle, towards its scapular end, is compressed and broad from
above downwards, but in the extent of its inner curve it is more or
less prismatic or cylindrical. In its description, four surfaces of the
shaft may be distinguished, together with the two extremities.

Fig. 70. —Tue Ricut Cia-
victe. (A. 7.) 2

A, from above; B, from
below.

1, sternal end ; 2, acromial
end ; 2’, small facet for arti-
culation with the acromion ;
3, groove on the lower
surface for the subclavius
muscle ; 4, rough elevation
at the place of attachment
of the coraco-clavicular liga-
ments ; 5, rough depression
at the place of attachment
of the costo-clavicular or rhomboid ligament ; 6, in front, the mark of the attachment of
the pectoralis major ; 7, that of the deltoid muscle.

The superior surface is broadest in its outer part; it is principally
subcutaneous, but near the inner extremity presents a slight roughness,
marking the clavicular attachment of the sterno-cleido-mastoid muscle.
The anterior surface opposite the outer curve is a mere rough border,
from which the deltoid muscle takes origin, but in the inner half of its
extent is broadened out into an uneven space more or less distinctly
separated from the inferior surface, and giving attachment to the

_pectoralis major muscle. The posterior surface is broadest at the inner
extremity, and smooth in the whole extent of the internal curvature ;
but towards its outer extremity it forms a narrow rough border which
separates it from the superior surface, and gives attachment-to the
trapezius muscle. On the inferior surface an elongated roughness near
the scapular extremity marks the attachment of the coraco-clavicular
ligaments ; extending inwards from this, over the middle third of the
bone, is a groove in which the subclavius muscle is inserted ; and near
the sternal end is a smaller rough depression, to which the costo-
clavicular ligament is attached. On this surface also is found the open-
ing of a small nutritious foramen.

The sternal end is the thickest part of the clavicle. It presents a
somewhat triangular concavo-convex surface, with its most prominent

THE HUMERUS, 85

angle directed downwards and backwards. The scapular end is broad
and flat, and articulates by a small oval surface with the acromion.

Texture-—The interior of the clavicle contains coarse cancellated
tissue in its whole extent. Towards the middle of the shaft the spaces
widen out, and unite so as to form an irregular medullary cavity.

THE HUMERUS.

The humerus or arm-bone extends from the scapula to the bones of
the forearm, with both of which it is articulated. It hangs nearly
vertically from the shoulder, with an inclina- j
tion inwards towards the lower end. It is
divisible into a superior extremity, including
the head, neck, and greater and smaller tuber-
osities ; the shaft ; and the inferior extremity,
including the external and internal condylar
eminences, and the inferior articular surface.
In general form it is subcylindrical and
slightly twisted.

Fig. 71.—Ricut Humervs From Berorr. (A.T.) }

1, the articular head ; 2, lesser tuberosity ; 3, greater
tuberosity ; 4, neck ; 5, bicipital groove ; 6, inner bicipital
ridge, and mark of the attachment of the latissimus dorsi
and teres major muscles ; 7, outer bicipital ridge, and rough
surface of insertion of the pectoralis major, running down
into 7’, the triangular mark of the insertion of the deltoid ;
8, spiral groove; 9, inner ridge of the humerus; 10,
trochlear articular surface ; 11, capitellum, or radial
condyle ; 12, epitrochlear or internal condylar eminence ;
15, capitellar or external condylar eminence ; 14, coronoid
depression or fossa.

The superior extremity is the thickest part of
the bone. The Head is a large hemispherical —
articular elevation, directed inwards, upwards, *
and somewhat backwards. The neck as de-
scribed by anatomists, is the ring of bone which
supports the head; inferiorly, it passes into
the shaft ; superiorly, it is a mere groove be-
tween the head and the great tuberosity. The
great tuberosity is a thick projection, continued
upwards from the external part of the shaft,
and reaching nearly to the level of the upper
margin of the head; ic is surmounted by
three flat surfaces, the uppermost of which
gives attachment to the supraspinatus muscle,
the lowest to the teres minor, and the inter-
mediate one to the infraspinatus muscle.
Separated from the great tuberosity by the
commencement of the bicipital groove, the
sinall tuberosity, rounded and prominent, looks directly forwards and
gives attachment to the subscapularis muscle.

The shaft or body, thick and cylindrical stiperiorly, becomes expanded
transversely, and somewhat three-sided inferiorly. It is divided into

86 BONES OF THE UPPER LIMB.

anterior and posterior faces by lateral lines, slightly marked in the
upper and middle parts, but more ypulngub in the lower, where they
pass into the condylar ridges. Superiorly on its anterior aspect is the
bicipital groove, so named from lodging the long
Fig. 72. tendon of the biceps muscle: this groove, com-
mencing between the tuberosities, descends with
an inclination inwards, and is bounded by two
rough ridges, the external and most prominent of
which gives ‘attachment to the pectoralis major
muscle, “the internal to the latissimus dorsi_and™
teres major. Towards the middle of the shaft, on
the inner lateral line, is a rough linear mark where
the coraco-brachialis muscle is inserted, and lower
down there is a medullary foramen directed down-
wards into the interior of the bone. On the external
part of the shaft, near its middle, in a line ante-
riorly with the external bicipital ridge, is a large,
rough, and uneven surface, of a triangular shape,
the impression of the deltoid muscle. Below this
the external bicipital ridge is continued into a
smooth elevation which, descending on the front
of the shaft to the inferior extremity, separates an
external from an internal surface, while at the sides
two sharp edges, the external and internal condylar
ridges spring from the eminences of the same name
and ascend for some distance, separating the
anterior from the flat posterior surface. About
the middle of the shaft externally, a broad depres-
sion, the spiral groove, winds downwards and for-
wards, limited above by the deltoid impression and
below by the external condylar ridge, and lodges
the musculo-spiral nerve and the accompanying
artery.

Fig. 72.—Ricut Humervs From peninp. (A. 7.) 3}

1, 3, 8, & 10, the same as in Fig. 71; 15, is placed above
the olecranon fossa.

The inferior extremity is much enlarged later-
ally, flattened from before backwards, and is curved
slightly forwards. Projecting on either side
are the external and internal condylar eminences (the
condyles of most authors, epicondyle and epitrochlea of Chaussier), the in-
ternal of which is much more prominent than the external, and is slightly
inclined backwards. The inferior articular surface is divided by a ridge
into two parts. The external part, articulated with the radius, con-
sists of a rounded eminence directed forwards, called the capitellum,
and a groove internal to it; it does not extend to the posterior sur-
face. The internal part, the frochlea, articulates with the ulna, and
extends completely round from the anterior to the posterior surface
of the bone; it is grooved down the middle like the surface of a
pulley, and is somew ‘hat broader behind than in front ; anteriorly, its
margins are inclined downwards and inwards ; posteriorly, upwards
and “outwards, and so that, seen from behind, it lies in the middle part

Mildly) es
10

THE RADIUS. 87

of the bone. Anteriorly, the internal margin of the trochlea is the
most prominent, and widens below into a convexity parallel to the
groove ; posteriorly, the external margin is most prominent. Above
the trochlea posteriorly is a large and deep pit, the olecranon fossa,
which receives the olecranon process of the ulna in extension of the
forearm ; and above it anteriorly, separated from the olecranon fossa
only by a thin lamina of bone, is the much smaller coronoid fossa,
which receives the coronoid process in flexion. Above the capitellum
is a shallow depression, into which the head of the radius is pressed
in complete flexion.

Varieties. —A small hook-like process, with its point directed downwards, is
not unfrequently found in front of the internal condylar ridge, the swpracon-
dyloid process. From its extremity, a fibrous band, giving origin to the pronator
radii teres muscle, passes to the internal condylar eminence, and through the
arch thus formed passes the median nerve, accompanied frequently by the brachial
artery, or bY large branch rising from it. This process represents a portion of
the bone completes a foramen in carnivorous animals. (See Struthers, Edin.
Med. Journ., 1848 ; Gruber, “‘ Canalis supracondyloideus humeri,” Mem. de l’Acad.
Imp. de St. Petersburg, 1859, p. 57.) The thin plate between the olecranon and
coronoid fossz is sometimes perforated,

THE RADIUS.*

The radius is the external of the two bones of the forearm, and
extends from the humerus to the carpus. It articulates with the
humerus, the ulna, the scaphoid, and the semilunar bones.

The head, or superior extremity, is disc-shaped, with a smooth ver-
tical margin. It presents on its summit a depression, which articulates
with the capitellum of the humerus, and is surrounded by a convex
part, broadest internally where it glides upon the groove internal to
the capitellum. The smooth, short, cylindrical surface of the vertical
margin, likewise broadest internally, rolls in the small sigmoid cavity
of the ulna, and within the orbicular ligament. The head is supported
on a constricted portion, named the neck.

The shaft or body is slightly curved, with the convexity directed
outwards and backwards. On its internal aspect superiorly, where it
is continuous with the neck, is the becipital tuberosity, to the posterior
border of which is attached the tendon of the biceps muscle. Below
the bicipital tuberosity the shaft presents three sides, the external of
which is rounded into the others by smooth convex margins, while the
anterior and posterior surfaces are separated by an acute internal
margin, which gives attachment to the interosseons ligament. The
external surface is convex transversely as well as longitudinally ; it is
marked near the middle by an oval rough part, about one inch and a
half long, which gives insertion to the pronator radiiteres. The
anterior surface is marked in its upper part by an oblique ridge, below
which is a shallow longitudinal groove for the flexor longus pollicis ;
inferiorly it is expanded, and presents a flat impression corresponding
with the pronator quadratus ; and above the middle is the foramen for
the medullary vessels, directed upwards into the bone. The posterior
surface presents slight oblique impressions of the extensor muscles of
the thumb.

The lower extremity of the radius, broad and thick, and somewhat

* Tn anatomical description the forearm is supposed to be placed in supination, with
the thumb directed outwards and the palm of the hand looking forwards.

88 BONES OF THE UPPER LIMB.

quadrilateral, presents inferiorly a large surface, which articulates with
the carpus, and internally a small one, which articulates with the ulna.
The carpal articular surface, slightly concave, is divided by a line into
a quadrilateral internal part, which articulates with the semilunar bone,
and a triangular external part, which articulates with the scaphoid
bone. The ulnar articular surface is placed at a right angle with the
inferior surface ; it is concave from before backwards, forming a semi-
lunar cavity, 11 which the rounded lower end of the ulna plays. At
the external angle of the inferior surface a part projecting downwards,
called the styloid process, gives attachment to the external lateral liga-
ment of the wrist joint, while the anterior and posterior margins are

Fig. 73. Fig. 74. Fig. 73.—Ricut Rapius FROM BEFORE.
Fig. 74.—Ricut Rapius rRoM BEHIND. (A. T.) 3

1, head, showing the hollow above for the humerus,
and the vertical surface surrounding it for the ulnar
articulation ; 2, the neck ; 3, the tubercle; 4, is
opposite to the oblique line ; 5, interosseous ridge ;
the shaded part near 5 marks the slight hollow in
which the flexor longus pollicis muscle lies ; 6, car-
pal articular surface ; 7, styloid process ; 8, the
articular hollow for the lower end of the ulna; 9,
mark of the attachment of the pronator radii teres ;
10 and 11, oblique impressions of the extensor
longus digitorum and extensor ossis metacarpi
pollicis ; between 7 and 8, dorsal grooves for the
tendons of the extensor muscles.

likewise rough and prominent for other
ligaments. On its external posterior as-
pects the inferior extremity of the radius
is marked by grooves, which transmit the
extensor tendons. Thus, on the external
border, is a flat groove directed down-
wards and forwards, which lodges the
extensor ossis metacarpi and extensor
primi internodii pollicis; and on the
posterior surface are three grooves, the
middle one of which, oblique and nar-
row, and with prominent borders, lodges
the extensor secundi internodii pollicis ;
while of the two others, which are broad
‘ and shallow, the external, subdivided by
a slight mark, gives passage to the ex-
tensores carpi radiales longior and bre-
vior, and the internal transmits the extensor communis digitorum and
extensor indicis.

THE ULNA.

The ulna is the internal of the two bones of the forearm. It is
longer than the radius by the extent of the olecranon process. It is
inclined downwards and outwards from the humerus in such a direc-
tion that a straight line passing from the great tuberosity of the
humerus downwards through the capitellum would touch the lower
end of the ulna.

The ulna articulates with the humerus and the radius: in the

THE ULNA. $9

natural skeleton it is not in contact with the carpal bones, being sepa-
rated from the cuneiform bone by an interarticular fibro-cartilage.

The superior extremity is of large size, and presents for articulation
with the humerus a large articular surface, the great sigmoid cavity,
which looks forwards and is bounded in its posterior and upper part by
the olecranon, a thick process continued upwards from the shaft, and
in its lower part by the coronoid process, which projects forwards.
The great sigmoid cavity is concave from above downwards, and is
convex from side to side, being traversed by a vertical ridge. The part
external to this ridge is broad and convex above, while the part internal
to the ridge is broad and concave below: a slight constriction, and

Fig. 75.—Ricut ULNA FROM BEFORE.
Fig. 76.—RicHt ULNA FROM BEHIND. (A. T.) §

1, point or beak of the olecranon ; 2, tuberosity of
the olecranon ; 3, end of the coronoid process ; 4,
great sigmoid articular surface ; 5, lesser sigmoid
cavity, and below it the surface for the supinator
brevis muscle; 6, interosseous ridge; 7, lower
extremity or head; 8, styloid process ; 9, rough
surface of insertion of the brachialis anticus
muscle; below 10, the oblique line marking the
attachment of the pronator quadratus muscle ; 11,
triangular surface for the anconeus muscle ; 12,
upper part of the posterior border, to the right of
which the depressions for the long extensor muscles
of the fingers occupy the posterior surface.

sometimes a notch of division occurs
across the middle of the cavity. Con-
tinuous with the great is the small sig-
moid cavity, a small articular surface on
the outer side of the base of the coronoid
process, slightly concave from before back-
wards, and articulating with the cylin-
drical part of the head of the radius.
Superiorly the olecranon is broad and un-
even, terminating in front in an acute
process or beak, which overhangs the
ereat sigmoid cavity, and which in exten-
sion of the elbow passes into the olecranon
fossa of the humerus, and behind in a
rectangular prominence or tuberosity,
which forms the point of the elbow, and
gives attachment to the triceps extensor muscle. The posterior surface
of the olecranon is subcutaneous and continuous with the posterior
margin of the shaft of the ulna. The extremity of the coronoid process
is sharp and prominent, and is received during flexion into the
coronoid fossa of the humerus: its superior surface forms part of the
surface of the great sigmoid cavity ; the inferior surface rises gra-
dually from the anterior surface of the bone, and is covered by a large
triangular roughness which gives insertion to the brachialis anticus
muscle.

The body or shaft in the upper three-fourths of its extent is three-

——

SZ

SS

90 BONES OF THE UPPER LIMB.

sided, and presents a slight curve with the convexity backwards, but
near the lower extremity it is slender, straight and cylindrical. The
anterior surface is grooved in the upper half, where the flexor profundus
muscle takes origin ; and at its lower end has an oblique line to which
the pronator quadratus is attached. Placed near the upper third is a
foramen for vessels, directed upwards into the medullary cavity. The
internal surface is smooth, and somewhat depressed superiorly on the
side of the olecranon, where it gives attachment to the flexor profundus
muscle, while inferiorly it is subcutaneous. The posterior surface, more
uneven, looks outwards and backwards; an oblique ridge descending
from behind the small sigmoid cavity, limits superiorly a triangular
area, which extends over the outer side of the olecranon and gives
attachment to the anconeus muscle; immediately below the small
sigmoid cavity is a short space looking directly outwards, to which
the supinator brevis is attached : while the remaining and largest part
of this surface is slightly impressed by the extensor muscles. Of the
three margins, the anterior and posterior are rounded, and for the most
part smooth ; the external is sharp, and gives attachment to the inter-
osseous ligament.

The inferior extremity presents a rounded articular head ; and on the
internal aspect of the head a short cylindrical projection, the sfyloid
process, Which descends in a line with the inner and posterior surface of
the shaft, and gives attachment to the internal lateral ligament of the
wrist joint. The head presents two aspects, of which one, flattened
and circular in form, looks towards the wrist joint; whilst the other,
narrow and cylindrical, looks outwards, and is received into the semi-
lunar cavity in the contiguous border of the radius. ‘The head and the
styloid process are separated posteriorly by a groove, which is traversed
by the tendon of the extensor carpi ulnaris ; and inferiorly by a de-
pression, into which the triangular fibro-cartilage which intervenes
between the ulna and the carpus is inserted.

THE CARPUS.

The carpus is composed of eight short bones, whica are disposed in

Fig. 77.—SeM1-DIAGRAMMATIC VIEW OF
THE Ricur Carpus AND PART OF THE
MeracarpaL Bonrs, FROM BEFORE, THE
CARPAL BoNES BEING SLIGHTLY SEPARATED
TO SHOW THE GENERAL MODE OF THEIR
CONNECTION WITH EACH OTHER. (A. T.) 3

1, scaphoid bone ; 2, semilunar, pre-
senting, as often occurs, a small surface of
articulation with the unciform bone; 3,
cuneiform ; 4, pisiform ; 5, trapezium, the
figure is placed upon the ridge, to the in-
side of which is the groove for the tendon
of flexor carpi radialis ; 6, trapezoid ; 7, os
magnum, the figure is placed on the
tuberosity ; 8, unciform, the figure is
placed on the uncitorm process. The articulation of the os magnum with the fourth
metacarpal bone is represented somewhat too large.

two ranges, four in each range. Enumerated from the radial to the
ulnar side, the bones which constitute the first or superior range are

THE CARPAL BONES. 91

named scaphoid, semilunar, cuneiform, and pisiform; those of the
second or inferior range, trapezium, trapezoid, os magnum, and unci-
form.

The dorsal surface of the carpus is convex, the palmar is concave
from side to side, the concavity beg bounded by four prominences,
one at the outer and one at the inner extremity of each range. The
anterior annular ligament is stretched across the carpus between these
prominences, so as to form a canal for the transmission of the flexor
tendons.

The superior surfaces of the scaphoid, semilunar, and cuneiform
bones form, when in apposition, a continuous convexity which corre-
sponds with the concavity presented by the radius and the interarticular
cartilage, while the pisiform bone is attached in front of the cuneiform,
with which alone it articulates. The line of articulation between the
superior and inferior ranges is concayo-convex from side to side, the
trapezium, trapezoid and os magnum bounding a cavity which lodges
the external part of the scaphoid, and the os magnum and unciform
tising up in a convexity, which is received into a hollow formed by the
scaphoid, semilunar, and cuneiform bones.

The scaphoid bone, the largest and most external of the first row
of carpal bones, is of a curved form, and lies with its longest axis
directed outwards and downwards. Its superior surface, convex and
smooth-for articulation with the radius, is inclined backwards, so that
the posterior surface of the bone is not so deep as the anterior. The
internal surface narrow from above downwards, articulates with the
semilunar bone. The outer extremity, rough superiorly for the attach-
ment of ligaments, presents inferiorly an articular convexity, which
occupies the hollow formed by the upper surfaces of the trapezium and
trapezoid bones, and is continuous with a large concave surface ex-
tending over the rest of the inferior aspect of the bone, and articulating
with the os magnum. The fore part of the outer extremity of the
scaphoid bone projects forwards, forming one of the tubercles to which
the anterior annular ligament is attached. The scaphoid articulates
with five bones, viz., the radius, the semilunar, trapezium, trapezoid,
and os magnum.

The semilunar bone, irregularly cubic, is named from the crescentic
concavity from before backwards of its inferior surface, which rests on
the head of the os magnum, and frequently also by a bevelled edge
slightly on the unciform bone. Its external surface is vertical, and
articulates with the scaphoid bone ; its internal surface looks down-
wards and inwards, is much deeper and narrower than the external, and
articulates with the cuneiform. The convex superior surface, which
articulates with the radius, is inclined, like that of the scaphoid, more
backwards than forwards and hence the anterior surface is deeper than
the posterior. The semilunar articulates with five bones, viz., the radius
scaphoid, cuneiform, os magnum, and unciform.

The cuneiform bone is somewhat wedge-shaped, its internal extre-
mity, rough for ligaments, forming the blunt narrow end of the wedge.
Superiorly it presents an articular surface, which glides upon the
triangular cartilage interposed between it and the ulna ; externally it
articulates with the semilunar bone, and inferiorly with the unciform,
by means of a surface which is concayo-convex from without inwards.
Its anterior surface is distinguished from the posterior by a smooth

92 BONES OF THE UPPER LIMB.

circular facet on its outer half, which articulates with the pisiform bone,
The cuneiform articulates with three bones, viz., the semilunar, pisiform,
and unciform.

The pisiform bone lies on a plane anterior to the other bones of the
carpus. Posteriorly it possesses an articular surface, which rests on the
cuneiform bone. ‘The mass of the bone is so inclined from this surface
dewnwards and outwards, that the pisiform bone of one hand is distin-
guishable from that of the other.

The trapezium bone is the most external of the second row of
carpal bones. It presents a rhombic form when seen in its dorsal or
palmar aspect, and has its most prominent angle directed downwards.

Fig. 78. Fig. 78.—Dorsat View oF THE CARPUS, WITH A
PORTION OF EACH OF THE METACARPAL Bonks. 4
1, scaphoid ; 2, semilunar ; 3, cuneiform ; 4,
pisiform ; 5, trapezium ; 7, trapezoid ; 8, os mag-
num ; 9, unciform.

Its anterior surface is marked by a
vertical groove traversed by the tendon
of the flexor carpi radialis muscle, and
external to the groove by a ridge, or
tubercle, one of the four prominences
which give attachment to the anterior
annular ligament. Of the internal sides
of the rhomb, the superior articulates with the scaphoid bone, the inferior
with the trapezoid bone, and by a small facet close to the inferior angle
also with the second metacarpal bone. Of the external sides the supe-
rior is rough, and the inferior presents a smooth surface, convex from
behind forwards, and concave from without inwards, which articulates
with the metacarpal bone of the thumb, and is separated by a rough
line at the yaferior angle from the surface for the second metacarpal
bone. The trapezium articulates with four bones, viz., the scaphoid,
trapezoid, and first and second metacarpals.

The trapezoid bone is considerably smaller than the trapezium.
Its longest diameter is from before backwards. Its posterior surface,
which is pentagonal, is much larger than the anterior. The external
inferior angle of the anterior surface is distinguished by being pro-
longed a little backwards between the trapezium and second metacarpal
bone. The superior surface articulates with the scaphoid bone ; the
external with the trapezium ; the internal with the os magnum; and
the inferior by a large surface convex from side to side with the second
metacarpal bone. The trapezoid articulates with four bones, viz., the
scaphoid, trapezium, os magnum, and second metacarpal bone.

The os magnum is the largest of the carpal bones. In form it is
elongated vertically, rectangular inferiorly, rounded superiorly. The
articular surface of the superior extremity or ead is prolonged on the
outer, but not on the inner side, and is continued further down behind
than in front. A neck is formed beneath by depressions on the anterior
and posterior surfaces. The anterior surface of the bone is much nar-
rower than the posterior. The posterior surface projects downwards
at its internal inferior angle. On the outer side beneath the surface
for the scaphoid is a short surface for the trapezoid bone ; and on the
inner side is a vertically elongated surface which articulates with

METACARPAL BONES 93

the unciform bone. Inferiorly this bone articulates by three distinct
surfaces, of which the middle is much the largest, with the second,
third, and fourth metacarpal bones. The os magnum articulates with
seven bones, viz., the scaphoid, semilunar, trapezoid, unciform, and
second, third, and fourth metacarpal bones.

The umciform bone is readily distinguished by the large process
projecting forwards and curved slightly outwards on its anterior sur-
face. Seen from the front or behind, it has a triangular form. Its
external surface is vertical, and articulates with the os magnum ; its
inferior surface is divided into two facets which articulate with the
fourth and fifth metacarpal bones; its superior surface, meeting the
cuneiform, is concavo-convex, inclines upwards and outwards towards
the head of the os magnum, and is separated internally by a rough
border from the inferior surface. The unciform articulates with five
bones, viz., the os magnum, semilunar, cuneiform, and fourth and fifth
metacarpal bones.

THE METACARPUS.

The metacarpus, the part of the hand which supports the fingers,
consists of five shafted bones, diverging slightly from each other, and
which are numbered from without inwards.

Fig. 79.—Tur Rieut HAND FROM BEFORE.
CAIN)

s, scaphoid bone ; 7, semilunar; c, cuneiform ;
p, pisiform ; t, trapezium; next it the trape-
zoid, not lettered ; next the os magnum, also not
lettered ; uw, unciform.

Ito V, the metacarpal bones ; 1, 3, first and
second phalanges of the thumb; 1, 2, 3, the
first, second, and third phalanges of the little
finger, and similarly for the other three fingers,
not marked ; * one of the sesamoid bones of the
thumb seen sideways.

The metacarpal bones are placed in
a segment of an arch transversely, and
being at the same time slightly curved,
longitudinally they present a concavity
directed forwards. They are terminated
at their carpal extremities by expanded
portions of different forms, and at the
digital ends by large rounded heads.
The first metacarpal bone is thicker
and shorter than the others. Of the remaining bones the third is the
longest and thickest, the second, fourth, and fifth decreasing regu-
larly in length, according to their position from without inwards.

The shaft of the first metacarpal bone is somewhat compressed from
before backwards, flat behind, and transversely convex in front. The
shafts of the others are prismatic, presenting a broad surface towards
the back of the hand, and towards the palm a rounded margin between
the two lateral surfaces. They are most slender immediately beyond
the carpal extremity, and become gradually thicker towards the head.
They present on their dorsal surfaces each a triangular subcutaneous

94 BONES OF THE UPPER LIMB.

area, bounded by lines which, proceeding from the sides of the head,
pass upwards and converge in the second, third, and fourth metacarpal
bones opposite the middle of the carpal extremity, and in the fifth
towards its inner side.

The heads or digital extremities articulate with the proximal phalanges.
Their smooth, rounded surfaces are broader, and extend further on the
palmar than on the dorsal aspect of the bones ; and on the sides pre-
sent hollows and elevations for the attachment of ligaments.

The carpal extremity presents distinctive peculiarities in each meta-
carpal bone. That of the first has only one articular surface, concave
from before backwards, and convex from side to side, which articulates
with the trapezium ; and posteriorly a rough prominence, to which the
extensor ossis metacarpi pollicis is attached. The second presents a
transversely concave surface which receives the trapezoid bone ; on the
radial side it articulates by a small facet on its posterior part with the
trapezium, on the ulnar side with the third metacarpal bone, and by a
narrow facet wedged between the third metacarpal and trapezoid bones,
with the os magnum. The third bone articulates superiorly with the
os magnum, and on the sides with the contiguous metacarpal bones :
at its posterior and outer angle it forms a projection upwards. The
fourth articulates principally with the unciform bone above, but
also by a narrow facet with the os magnum ; on its radial side are two
small surfaces, and on the ulnar side one, for articulation with the
adjacent metacarpal bones. ‘The fifth articulates superiorly with the
unciform bone by means of a concave surface inclined slightly out-
wards, and externally with the fourth metacarpal bone, while on its
ulnar side it presents a rough and prominent tuberosity.

From the proximal position of its epi-
physis, the metacarpal bone of the thumb
has been considered by Winslow and some
other anatomists, as a phalanx of the first
row, and the bone which it supports a

phalanx of the middle row, Buarwe, wre A
MAST Quen nadhy BAW Wa Oratania |

Fig. 80.—Rieut Hand sEEN FROM BUHIND,
(A. T.) ¥

The indications are the same as in the pre-
ceding figure.

THE DIGITAL PHALANGES.

The digital phalanges, or wternodia,
are fourteen in number ; three for each
finger, except the thumb, which has
only two.

Those of the first row are slightly
curved like the metacarpal bones.
Their dorsal surfaces are smooth and
transversely convex ; the palmar are
flat from side to side, and bounded by
rough margins, which give insertion to
the fibrous sheaths of the flexor tendons. Their proximal extremities
are thick, and articulate each by a transversely oval concave surface with
the corresponding metacarpal bone. Their distal extremities, smaller and

OSSIFICATION OF SHOULDER BONES. 95

more compressed antero-posteriorly, are divided by a shallow groove into
two condyles.

Those of the meddle row are four in number. Smaller than those of the
preceding set, they resemble them in form, with this difference, that
their proximal extremities present, on the articular surface a slight
middle elevation and two lateral depressions, adapted to articulate with
the condyles of the first phalanges.

The terminal or wungual phalanges, five in number, have proximal
extremities similar to those of the middle row, but with a rough
depression in front, where the flexor tendons are inserted. They taper
towards their somewhat flattened and expanded free extremities, which
are rough and raised round the margins and upon the palmar aspect in
the ungual process.

SESAMOID BONES.—A pair of sesamoid bones is placed in the palmar
wall of the metacarpo-phalangeal articulation of the thumb; and
similar nodules, single or double, are sometimes found in the corre-
sponding joint of one or more of the other fingers, most frequently of
the index and little fingers.

OSSIFICATION OF THE BONES OF THE UPPER LIMB

With the exception of the clavicle, all the bones of the upper limb begin to
ossify from cartilage.

The scapula is ossified from a single osseous nucleus for the body, and addi-
tional centres for the coracoid process, acromion, base, and lower angle. The

\

Fig. 81.

1 year. 15 or 16 years. 17 or 18 years. 22 years,
Fig. 81.—-OssrricaTION oF THE Scapuna (R. Quain).

A, about one year. 1, shows the large spreading ossification, from the primary centre.
2, the commencing nucleus in the coracoid process.

B, about fifteen or sixteen years. The coracoid process (represented as too little
ossified in the figure) is now partially united at its base; a nucleus, 8, has appeared
in the acromion, and another, 4, at the lower angle.

C, male scapula at seventeen or eighteen years ; a second point, 5, has appeared in the
acromion, and ossification has advanced into the ridge of the base, 6.

D, the scapula of a man of about twenty-two years of age; the acromion and the ridge
of the base are still separate. B, C, and D, are about the fourth of the natural size.

96 BONES OF THE UPPER LIMB.

nucleus for the body appears a little behind the glenoid cavity about the 7th or
Sth week. Around this centre is formed a triangular plate of bone, from near
the upper margin of which about the 3rd month the spine appears as a slight
ridge. At birth the coracoid and acromion process, the base and inferior angle,
the edges of the spine and of the glenoid cavity are cartilaginous. The nucleus
of the coracoid process is especially worthy of attention, both because it appears
in the first year, while the other supplementary nuclei are formed only after pu-
berty, and because, although reduced to a mere epiphysis in mammals, it forms a
distinct and sometimes large bone in other vertebrate animals. The coracoid
process is united to the body about the age of puberty. The acromion process is
cartilaginous till the 14th or 16th year, when two distinct nuclei appear. These
soon coalesce and form an epiphysis which is united to the spine from the 22nd
to the 25th year. The cartilage of the base, which it may be noticed corresponds

Fig. 82.

Fig. 82.—Postrrion Aspect oF THE Srernum anp Ricur SHovLpDER GIRDLE FROM
A Favs oF ABout FouR montTHs (Flower after Parker). 13

The dotted parts are cartilaginous ; ost, omosternum, afterwards becoming the inter-
articular fibro-cartilage ; yc, precoracoid of Parker ; a, acromion ; cl, shaft of clavicle ;
mss, mesoscapular segment of Parker ; c, coracoid ; ge, glenoid cavity ; gb, glenoid border ;
cb, coracoid border ; af, anterior or supraspinous fossa; pf, posterior or infraspinous
fossa ; ss, suprascapular border.

toa more largely developed permanent cartilage or bone found in many animals,
becomes the seat of ossification about the 16th to the 18th year, by the appear-
ance of a nucleus at the inferior angle, and thereafter of a line of osseous
deposit extending upwards throughout its length. The epiphysis thus formed,
together with an epiphysial lamina which occasionally forms the border of the
glenoid cayity, are united to the body about the 25th year.

Fig. 83. Fig. 83.—OssIFIcATION OF THE CLAVICLE
(R. Quain).

a, the clavicle of a foetus at birth, osseous in
the shaft, 1, and cartilaginous at both ends.

b, clavicle of a man of about twenty-three
years of age; the shaft, 1, fully ossified to the
acromial end ; the sternal epiphysis, 2, is repre-
sented rather thicker than natural.

The clavicle begins to ossify before any other bone in the body. Its ossifica-
tion commences before the deposition of cartilage in connection with it, but
afterwards progresses in cartilage as well as in fibrous substance. It is formed

OSSIFICATION OF THE HUMERUS. 97

from two separate centres, the one appearing about the 6th week, for the shaft
and acromial end, the other appearing about the 18th to the 20th year for an epi-
physis at the sternal end. The epiphysis is united to the shaft about the 25th
year.

In the humerus an ossific nucleus appears near the middle of the shaft in
the 8th week. It gradually extends, until at birth only the ends of the bone
are cartilaginous, About the beginning of the 2nd year the nucleus of the
head appears, and during the 3rd year that for the great tuberosity. The lesser
tuberosity is either ossified from a distinct nucleus which appears in the 5th
year, or by extension of ossification from the great tuberosity. These nuclei
unite together about the 5th year to form an epiphysis, which is not united to
the shaft till the 20th year. In the cartilage of the lower end of the bone four
separate nuclei are seen, the first appearing in the capitellum in the 3rd year,

Fig. 84,

Fig. 84.— OsstFication or THE Humerus (R. Quain).

A, from a full grown feetus; B, at two years; C, in the third year; D, at the
beginning of the fifth year ; KE, at about the twelfth year ; F, at the age of puberty.

1, the primary centre for the shaft ; 2, nucleus for the articular head ; 3, that for the
great tuberosity ; 4, for the radial condyle and adjacent part of the trochlea ; 5, for the
inner or trochlear eminence ; 6, for the inner part of the trochlea; 7, for the external
or capitellar eminence. In this and the following figures the more advanced bones are
shown on a smaller scale than the earlier ones.

The nucleus of the internal condylar eminence appears in the 5th year, that of
the trochlea in the 11th or 12th year, and that of the external condylar eminence
in the 13th or 14th year. The nucleus of the internal condylar eminence forms
a distinct epiphysis which unites with the shaft in the 18th year; the other
three nuclei coalesce to form an epiphysis, which is united to the shaft in the
16th or 17th year.

The radius is developed from an osseous nucleus, which eppears in the middle
of the shaft in the 8th week, and from an epiphysial nucleus in each ex-
tremity which only appear some time after birth. The nucleus in the carpal
extremity appears at the end of the 2nd year, while that of the head is not
seen till the 5th or 6th year. The superior epiphysis and shaft unite about
the 17th or 18th year; the inferior epiphysis and shaft unite about the 20th
year.

The ulna is ossified similarly to the radius, but ossification begins a few days
later. The nucleus of the shaft appears about the 8th week, that of the carpal

vol, I. H

98 BONES OF THE UPPER LIMB.

extremity in the 4th or 5th year. The upper extremity is formed chiefly in
connection with the shaft, except the point of the olecranon where a small

Fig. 85.—OssIFIcATION oF THE Raptus (R. Quain),
A, the radius of a full-grown fetus ; B, at about two years of age ; C, at five years;
D, at about eighteen years. } i
1, the primary piece or shaft ; 2, the ossific point of the lower or carpal epiphysis ;

3, that of the upper end. In D, the upper epiphysis is united to the shaft, while the
lower epiphysis is still separate.

Fig. 86.—OssirIcaTion oF THE Una. (R. Quain).

A, the ulna of a child at birth ; B, the ulna of a child at the end of the fourth year;
C, of a boy of about twelve years of age; D, the ulna of a male of about nineteen or
twenty years.

1, the primary piece of the shaft; 2, the nucleus of the lower epiphysis ; 3, the

nucleus of the upper epiphysis. In D, the upper epiphysis is united to the shaft, while
the lower one is still separate.

OSSIFICATION OF THE BONES OF THE HAND 99
epiphysis is formea from a distinct nucleus which appears in the 10th year.
This epiphysis is united to the shaft about the 17th year, while the inferior epi-
physis is only united to the shaft about the 20th year.

Fig. 87.

Fig. 87—OssIrIcaTIon oF THE Bonus or THE Hann.

A, represents the state of the bones and cartilages at the period of birth. The carpus
is entirely cartilaginous. Each of the metacarpal bones and digital phalanges has its
shaft ossified. ;

B, the state of the bones in a child at the end of the first year; the os magnum and
unciform bone have begun to ossify.

C, the condition about the third year. Centres of ossification are seen in the cuneiform
and in the proximal epiphysts of the first and the distal epiphysts of the other four meta-
carpal bones, and in the proximal epiphyses of the first row of phalanges.

D, the condition at the fifth year. Centres have been formed in the trapezium, and
later in the semilunar bone, and in the middle and distal phalanges : (the figure does not
show them distinctly in the middle phalanges. )

E, the condition at about the ninth year. Centres have been formed in the scaphoid
and trapezoid bones, and the more developed epiphyses of the metacarpal bones and
phalanges are shown in the first and second digits separately.

1, os magnum ; 2, unciform; 3, cuneiform ; 4, semilunar ; 5, trapezium ; 6, scaphoid ;
7, trapezoid ; 8, metacarpal bones, the principal pieces ; 8*, four metacarpal epiphyses ;
8’, that of the thumb ; 9, the first range of phalanges ; 9*, their epiphyses; 9’, that of
the thumb ; 10, second range of phalanges ; 10’, epiphyses of terminal phalanx of thumb,
11, terminal range of phalanges of the fingers ; 11*, their epiphyses.

H 2

100 BONES OF THE LOWER LIMB.

From what is stated above it appears that in the bones of the arm and
forearm the epiphyses which meet at the elbow-joint begin to ossify later, and
unite with their shafts earlier, than those at the opposite ends of the bones, while
in the bones of the thigh and leg the epiphyses at the knee-joint are the soonest
to ossify and the latest to unite with their shafts. In the bones of the arm and
forearm the nutrient foramina are directed towards the elbow ; in those of the
thigh and leg they are directed away from the knee. Thus in each bone the
epiphysis of the extremity towards which the nutrient foramen is directed is the
first to be united to the shaft.

The carpus is entirely cartilaginous at birth. Each carpal bone is ossified from
a single nucleus. The nucleus of the os magnum appears in the first year; that
of the unciform in the first or second year; that of the cuneiform in the third
year ; those of the trapezium and semilunar bones in the fifth year ; that of the
scaphoid in the sixth or seventh year; that of the trapezoid in the seventh or
eighth year ; and that of the pisiform in the twelfth year.

The Metacarpal bones and Phalanges are usually formed each from a prin-
cipal centre for the shafts and one epiphysis. The ossification of the shafts
begins about the eighth or ninth week. In the four inner metacarpal bones the
epiphysis is at the distal extremity, while in the metacarpal bone of the thumb
and in the phalanges it is placed at the proximal extremity. In many instances,
however, as was known to Albinus, and has been more fully shown by Allen
Thomson (Jour. of Anat., 1869), there is also a distal epiphysis visible in the
first metacarpal bone at the age of seven or eight years, and there are even traces
of a proximal epiphysis in the second metacarpal. In the seal and some other
animals there are always two epiphyses in these bones. The epiphyses begin to
be ossified from the third to the fifth year, and are united to their respective
shafts about the twentieth year.

V.—THE PELVIS AND LOWER LIMB.

The divisions of the lower limb are the haunch or hip, thigh, leg, and
foot. In the haunch is the innominate bone, which enters into the
formation of the pelvis; in the thigh is the femur; in the leg the
tibia and fibula ; and at the knee a large sesamoid bone, the patella.
The foot is composed of three parts; the tarsus, metatarsus, and
phalanges.

THE INNOMINATE BONE.

The innominate bone, os core, or pelvic bone, with its neighbour of
the opposite side and the addition of the sacrum and coccyx, forms the
pelvis ; it transmits the weight of the body to the lower limb. In
form it is constricted in the middle and expanded above and below,
and is so bent upon itself that the anterior margin of the upper part
looks outwards, while the lower part is directed inwards. On the
external aspect of the constricted portion is the acetabulum, a cavity
which articulates with the femur, and perforating the inferior expan-
sion is a large opening, the obturator foramen. The superior wider part
of the bone forms part of the abdominal wall: the inferior enters into
the formation of the true pelvis. The innominate bone articulates
with its fellow of the opposite side, with the sacrum, and with the
femur.

In the description of this bone it is convenient to recognise as
distinct the three parts of it which are separated in early life, viz., the

INNOMINATE BONE. 101

alium, os pubis and ischiwm. These three portions meet at the aceta-
bulum, in the formation of which they all take part ; and the os pubis
and ischium also meet on the inner side of the obturator foramen.

Fig. 88.—Ricur Os Innouinatum
FROM THE DORSAL Aspror. (A, T.) 3

1, anterior superior ; 2, anterior
inferior spinous process ; 3, pos-
terior superior ; 4, posterior in-
ferior spinous process ; 5, crest of
the ilium ; 6, surface occupied by
the gluteus medius muscle above
the superior curved line; above 3
and 4 is a rough surface to which
the gluteus maximus is attached ; 7,
surface between the superior and
inferior curved lines occupied by
the gluteus minimus; 8, groove
above the acetabulum for the pos-
terior tendon of the rectus femoris;
9, superior ramus of the pubis, and
pectineal eminence; 10, crest and
spinous process of the pubis: 11,
place of meeting of the descending
ramus of the pubis with the as-
cending ramus of the ischium ; 12,
spine ; and 13, tuberosity of the
ischium ; 14, cartilaginous surface
10 of the acetabulum ; 15, synovial de-
pression and pit for the round
ligament ; 16, thyroid or obturator
foramen; 17, greater, and 18,
lesser sciatic notches.

°
asi, .\%
iris My
Wry ye)

oO

The ilium constitutes the superior expanded portion of the bone, and
forms a part of the wall of the acetabulum by its inferior extremity.
Above the acetabulum it is limited anteriorly and posteriorly by margins
which diverge at right angles one from the other, and superiorly by an
arched thick and extensive border, 5, the crista iii. The crest 1s curved
like the letter f; the anterior extremity pointing slightly inwards and
the posterior outwards ; its surface is broadest in its anterior and pos-
terior thirds, it is rough for the attachment of muscles, and on it may
be distinguished an external and internal lip and an intermediate
space. The anterior extremity of the crest forms a projection forwards
called the anterior superior spine of the ilium, and, separated from it
by a concave border, and placed immediately above the acetabulum, is
another eminence called the anterior inferior spine: the projecting
posterior extremity of the crest forms the posterior superior spine,
and separated from it by a notch is the posterior inferior spine, below
which the posterior border of the bone is hollowed out into the great
sciatic notch. The external surface, or dorsum of the ilium, concavo-
convex from behind forwards, presents, close to the posterior extremity
of the crest, a roughness of some extent, to which the gluteus
maximus muscle is attached, and is traversed by two rough arched
snes, one of which, the superior curved line, beginning in front, at
the upper border of the bone, about an inch and a half from its

102 BONES OF THE LOWER LIMB.

anterior extremity, arches backwards to the upper part of the great
sciatic notch, while the other, the i/ferior curved line, shorter and less
strongly marked, extends from the space between the anterior spinous
processes to the middle of the great sciatic notch. The curved space
between the crest and the superior curved line, broad behind and
ointed in front, gives attachment to the gluteus medius muscle, while
that between the two curved lines gives attachment to the gluteus
minimus. The internal surface of the ilium is divided into three
parts. The anterior of these, the largest, is called the diac fossa ; it
is concave and smooth, and towards the middle of it the bone is very
thin. The posterior part is subdivided, presenting inferiorly, for
cartilaginous articulation with the sacrum, the smooth but uneven
auricular surface, broad in front and extending to the posterior inferior
spine behind ; and superiorly a more uneven and rough surface for
the attachment of ligaments. The third part, entering into the forma-
tion of the true pelvis, is not distinguished by any mark in the adult
from the ischium and os pubis ; it is separated from the iliac fossa
by a smooth border, the iliac portion of the @io-pectineal line, which
extends from the auricular surface to the pubic spine.

Fig. 89.—Riaut Os INNoMINATUM,
FROM THE INNER OR PELVIC
suRFACE. (A. 7.) 3
OSS) 4. Del. cli /mam elise

indicate the same parts as in the

preceding figure ; 19, iliac fossa 5

20, ilio-pectineal line ; 21, auricu-

lar cartilaginous sacro-iliac surface;

22, rough tuberculated surface for

the posterior sacro-iliac ligaments ;

23, oval surface of the symphysis

pubis ; 24, spinous process ; 25,

angle of the os pubis ; between 24

and 25, the crest ; between 17 and

20, the pelvic surface of the ilium.

The os pubis forms the
anterior wall of the pelvis,
and bounds the obturator
foramen in the upper half
of its extent. At its outer
and upper extremity it forms
a part of the acetabulum ;
atits inner extremity it pre-
sents an elongated oval sur-
face, articulating by fibro
cartilage with the bone of the opposite side, its junction with which
is called the symphysis pubis. The part which passes downwards and
outwards below the symphysis is called the inferior or descending
ramus, the upper part is called the superior or ascending ramus, and
the flat portion between the rami may be distinguished as the body.
The deep or pelvic surface of the os pubis is smooth ; the outer sur-
face is roughened near the symphysis by the attachments of muscles.
At the superior extremity of the symphysis is the angle of the pubis,
and extending outwards from this, on the superior border, is the

THE INNOMINATE BONE. 193

rough crest, terminating in the projecting spine. The descending
ramus is flat from before backwards ; the superior or ascending ramus
becomes prismatic, and increases in thickness as it passes upwards
and outwards, and between its posterior and superior surfaces there
is prolonged outwards from the spine a ridge which is the pubic
portion of the iio-pectineal line. he surface in front of this line is
covered by the pectineus muscle ; the inferior surface of the ramus
presents a deep groove for the obturator vessels and nerve directed from
behind forwards and inwards. On the superior surface above the aceta-
bulum there is a slight elevation, the cio-pectineal eminence, marking
the place of junction of the os pubis and ilium.

The ischium forms the posterior and inferior part of the os innomi-
natum, and bounds the obturator foramen in the lower half of its
extent. Superiorly it forms about two-fifths of the acetabulum, infe-
riorly it is enlarged in a thick projection, the ¢wberosity, and this part,
diminishing in size, is continued forwards into the ramus. On its
posterior border, behind the acetabulum, a sharp process, the spine,
projecting with an inclination inwards, forms the inferior limit of the
great sciatic notch, and is separated from the tuberosity by a short
interval, the small sciatic notch, against the smooth margin of which
glides the tendon of the obturator internus muscle. In front of this,
on the external surface, a horizontal groove, occupied by the tendon
of the obturatur externus muscle, lies between the inferior margin of
the acetabulum and the tuberosity. The tuberosity, which is the part
on which the body rests in the sitting posture, presents a rough surface
continuous with the internal margin of the ramus, and on which may
be distinguished four impressions, viz., on its upper and broad part two
slight hollows, which are placed side by side, the external corresponding
to the attachment of the semimembranosus muscle, and the internal to
the conjoined origin of the biceps and semitendinosus ; and inferiorly
two elongated rough elevations, likewise side by side, the external
giving attachment to the adductor magnus muscle, and the internal to
the great sacro-sciatic ligament: there is likewise along the outer
margin a rough elevated line, marking the place of origin of the
quadratus femoris muscle. The ramus of the ischium is flattened like
the descending ramus of the pubis, with which it is continuous on the
inner side of the obturator foramen.

The acetabulum is a cotyloid or cup-shaped cavity, looking outwards,
downwards, and forwards, and surrounded in the greater part of its
circumference by an elevated margin, which is most prominent at the
posterior and upper part; while at the opposite side, close to the
obturator foramen, it is deficient, forming the nolch or incisura. Its
lateral and upper parts present a broad bent ribbon-like smooth surface,
which articulates with the head of the femur, and in the recent state
is coated with cartilage, but the lower part of the cup and the region
of the notch are depressed below the level of the articular surface, lodge
amass of fat, and have no cartilaginous coating. Tather more than
two-fifths of the acetabulum are formed from the ischium, less than
two-fifths from the ilium, and the remainder from the os pubis. ‘The
iliac portion of the articular surface is the largest, the pubic the
smallest : the non-articular surface belongs chiefly to the ischium.

The obturator or thyroid foramen, also called foramen ovale, is internal
and inferior to the acetabulum. In the male it is nearly oval, with the

104 BONES OF THE LOWER LIMB.

long diameter directed downwards and outwards ; in the female it is
more triangular, or narrowed at its lower part. In the recent state it
is closed by a fibrous membrane, except in the neighbourhood of the
groove in its upper margin.

THE PELVIS,

The ossa innominata with the sacrum and coccyx form the osseous
walls of the pelvis.

Fig. 90.

Fig. 90.

Aputt Mater Petyis
SEEN FROM BEFORE,
IN THE ERECT AT-
TITUDE OF THE
Bopy, (A. 7.) 2

1, 2, anterior ex-
tremities of the
crests of the ilia in
front of the widest
transverse diameter
of the upper or false
pelvis ; 3, 4, aceta-
bula ; 5, 5, obturator
foramina; 6, sub-
pubic angle or arch.

Fig. 91.

Apuut Fematr Prt-
vis (A. T.) 2

Similarly placed with
that shown in the
preceding figure, and
illustrating by com-
parison with it, the
principal differences
between the male and
female pelvis. The
numbers indicate the
same parts as in the
preceding figure.

This part of the s eleton may be considered as divided into two parts
by a plane passing through the upper border of the symphysis pubis, the
sacral promontory, and the ilio-pectineal lines. The circle thus com-
pleted constitutes the brim or inlet of the lower or true pelvis ; the space
above it, between the iliac fosse, belongs really to the abdomen, but has
been called the upper or false pelvis. The inferior circumference, or
outlet of the pelvis, presents three large bony eminences, the coccyx and
the tuberosities of the ischia. Between the tuberosities of the ischia
in front is the swb-pubic arch, which bounds an angular space
extending forwards to the symphysis, and is formed by the descending
rami of the ossa pubis and the ascending rami of the ischia. The

THE PELVIS. 105

interval between the sacrum and coccyx and the ischium on each side
is bridged over in the recent state by the sacro-sciatic ligaments, which
therefore assist in bounding the outlet of the pelvis.

Position of the Pelvis.—In the erect attitude of the body, the
pelvis is so inclined that the plane of the brim of the true pelvis ‘forms
an angle with the horizontal, which varies in different individuals from

Fig. 92. Figs. 92 & 93.

SKETCHES OF THE MALE
AND FEMALE PELYIS
AS SEEN FROM ABOVE
AND IN FroNT. (A. T.)

In fig. 90 of the fe-
male pelvis the lines are
shown in which the di-
mensions of the pelvis
are usually measured at
the brim.

(t, p, antero-posterior
or conjugate diameter ;
t, 7, ‘transverse or
widest diameter; 0, 5,
0, 6, oblique diameters.

In the original speci-
mens, which were se-
lected as giving the fuil
average dimensions, the
following were the mea-
surements in inches :—

Antero-posterior dia-
meter — female, 44 ;
male, 4. Transverse
diameter—female 5}:
male, 44. Oblique dia-
meter—female, 5; male,

Al
+4-

60°to 65°. Thebase
of the sacrum was
found by Niigele
in a large number
of well-formed female bodies to be about 3% inches above the upper
margin of the symphysis pubis; the level of the top of the coccyx
he found varying from 22 lines above the apex of the pubic arch
to 9 lines below the same point, and on an average to be 7 or 3
lines above it (Nigele, “ Das weibliche Becken,” &c., Carlsruhe, 1820 ;
W ood, article “ Pelvis” in the Cyclopedia of Anatomy and Physiology).
The pelvic aspect of the sacrum, near its base, looks much more down-
wards than forwards, hence the sacrum appears at first sight to occupy
the position of the keystone of an arch ; but being in reality broader at
its pelvic than on its dorsal aspect, it is a keystone inverted, or having
its broad end lowest, and is supported in its place chiefly by cartilage
and ligaments, but also to a slight extent by the inward projection of
the anterior margin of the iliac articular surface. The line of pressure
of the weight of the body on the sacrum is directed downwards towards
the symphysis pubis, and the resistance of the head of the thighbone
on each side is directed upwards and inwards.

106 BONES OF THE LOWER LIMB.

The azis of the pelvis is the name given to a line drawn at right
angles to the planes of the brim, cavity and outlet, through their

ig. 94.—VERTICAL MEDIAN Fig. 94.
SECTION OF A FEMALE PEL-
vis (reduced from Nigele’s

fizure). 3

1, symphysis pubis ; 2, pro-
montory of the sacrum ; 3,
coeeygeal bones ; 4, anterior
superior spine of ilium; 5,
tuberosity of ischium ; 6,
spine of ischium (the obtura-
tor foramen is not represented
so pointed below as it gener-
ally is in females). The ver-
tical and horizontal lines in
the lower part of the figure
will assist the eye in judging
of the degree of inclination of
the pelvis, as illustrated by
the next figure.

central points. The pos-
terior wall, formed by
the sacrum and coccyx,
being about five inches
long and concave, while
the anterior wall at the symphysis pubis is only one and a half or two
inches long. The axis is curved; it is directed at the inlet upwards
and forwards towards the umbilicus, and at the outlet downwards
and a little forwards.

Fig. 95.—SkETcH OF PART OF THE Fig. 95.
Precepine Fiaure, SHOWING
tHE INCLINATION OF THE BRIM
or THE PELVIS AND ITs AXIS
IN THE Erect Posrurz. }

a, 6, line of inclination of the
brim of the true pelvis from
above the symphysis pubis to the
promontory of the sacrum ; e, f,
a line inclining backwards and
upwards, touching the lower edge
of the symphysis pubis and point
of the coccyx ; ¢, d, axis of the
brim at right angles to the plane
of the brim; d@ hg, curved axis
of the cavity and outlet.

Differences according
to Sex.—The size and
form of the pelvis differ
remarkably in the two
sexes. In the female the
constituent bones are more
slender and less marked
with muscular impressions;
the perpendicular depth is less, and the breadth and capacity greater ;
the ilia are more expanded than in the male; the inlet of the true

THE FEMUR. 107

pelvis is more nearly circular, the sacral promontory projecting less
into it ; the sacrum is Hatter and broader ; the depth of the symphysis
pubis is less, the pubic arch is much wider, and the space between the
tuberosities of the ischia greater.

The average dimensions of the pelvis, as measured in a number of
full-sized males and females, may be stated as follow, in inches :—

f

|

MALE. FEMALE. |

Distance between the widest part ee 7 le |

of the crests of the ila . : 10) toy Valu! 10$ to II |

Distance between the anterior |
superior spines of the ilia ; 9} to 10 10 — 103

‘Distance between the front of sym- |

physis pubis and the sacral spines 6s — 7 6s — 73

| ee: (Ts ln,

TRUE PELVIS. Brim. | Cavity. | Outlet. | Brim. | Cavity. | Outlet. |

——_ | | | |

; a Fg | ; |

Transverse diameter | 43 43 34 bE | 42 |

|Oblique diameter . . . .| 44 43 Ey a ae deer

eo diameter . “| 4 45 31 | 43 | Bk | 6

|

|

THE FEMUR.

The femur or thigh bone, the largest bone of the skeleton, is situated
between the os innominatum and the tibia. In the erect position of
the body it inclines inwards and slightly backwards as it descends, so
as to approach inferiorly its fellow of the opposite side, and to have its
upper end a little in advance of the lower. It is divisible into a
superior extremity, including the head and neck and two eminences
called trochanters, the shaft, and an inferior extremity expanded into
an external and an internal condyle.

At the superior extremity of the bone, the neck, surmounted by the
head, extends inwards, upwards, and slightly forwards, being set upon
the shaft at an angle of about 125° or 130°. The neck has a con-
stricted appearance, and its diameter from before backwards is less
than in the vertical direction, in which last greater strength is required
to sustain the weight of the body. It is shorter superiorly than
inferiorly, and the anterior surface is shorter than the posterior. The
head forms more than half a sphere, and is covered with cartilage in
the fresh state. Behind and below its central point is a small depres-
sion, which gives attachment to the round ligament of the hip joint.

The trochanter major is a thick truncated process prolonged upwards
in a line with the external surface of the shaft. In front it is marked
by the insertion of the gluteus minimus ; externally an oblique line
directed downwards and forwards indicates the inferior border of the
insertion of the gluteus medius muscle, and lower down a horizontal
line, continued upwards in front of the trochanter, marks the upper
limit of the vastus externus. Internally at its base, and rather behind
the neck, is the trochanteric or digital fossa, which gives attachment to
the obturator and gemelli muscles. The posterior border of the great
trochanter is prominent, and continued into a smooth elevation, the

v

108 BONES OF THE LOWER LIMB.

posterior intertrochanteric line, which passes downwards and inwards to

Fig. 96.—Frmur oF A MALE FROM BEFORE. Fig. 96.
(ASE ag

1, shaft ; 2, head; 3, neck ; 4, great tro-
chanter ; 5, small trochanter ; 6, anterior
inter-trochanteric line; 7, internal articular
condyle ; 8, external articular condyle ; 9, in-
ternal tuberosity ; 10, external tuberosity ;
11, the patella articular surface ; above it, 12,
the flat part of the femur sometimes called the
suprapatellar surface ; 13, the depression for
the tendon of the popliteus muscle.

i 6 py

‘hy

the small trochanter, and limits the
neck posteriorly. The small tro-
chanter, a conical rounded eminence,
projects from the posterior and inner
aspect of the bone, and gives at-
tachment to the tendon of the psoas
and iliacus muscles. The anterior
intertrochantertc line is a rough ridge
limiting the neck in front between
the two trochanters ; it indicates the
superior border of the crureus and
vastus internus muscles, and is con-
tinuous beneath the great trochanter
with the line which limits the vastus
extermus. :

The shaft is slightly arched from
above downwards, with the con-
vexity forwards. It is expanded at its
upper and lower ends. Towards the
centre it is nearly cylindrical, but
with an inclination to the prismatic
form. Its anterior and lateral sur-
faces, smooth and uniform, are
covered by the crureus and vasti
muscles. ‘The elevation which sepa-
rates the anterior from the internal
surface is at the upper part strongly
marked and inclined forwards, giving
the appearance to the bone as if the
forward inclination of the neck were
produced by a twisting outwards of
the upper end cf the shaft. The
lateral surfaces in the middle of their
extent approach one another behind,
being only separated by the linea
aspera. The /inea aspera is a pro-
minent ridge, extending along the
central third of the shaft posteriorly,
and bifurcating above and below. It
inclines slightly inwards in the mid- 7
dle, so as to male the external surface of the shaft seem concave in that

THE FEMUR. 109

part. It presents two sharp margins and a flat interval. The external divi-

Fig. 97.—Frmur or A Mane FROM BEHIND
(Arr

4, 5, 7, 8, 9, 10, and 13, the same as in the
preceding figure ; 2’, pit on the head for the
round ligament of the hip-joint ; 3’, the back of
the neck, showing a slight groove of the obturator
externus muscle as it passes over the capsular
ligament and neck ; between 4 and 5, the pos-
terior intertrochanteric ridge ; 14, rough im-
pression of the attachment of the gluteus
maximus muscle in the upper and outer continua-
tion of the linea aspera ; 15, two lines running
up towards the lesser trochanter from the linea
aspera, marking the attachments of the ad-
ductor brevis and pectineus muscles ; 16, flat
elevated surface of the linea aspera; 17, flat
triangular popliteal surface between the lower
divisions of the linea aspera; 18, intercondylar
notch ; 19, foramen for the nutritive or medul-
lary vessels.

sion of its superior bifurcation passes
up to the great trochanter, and in its.
course is strongly marked where the
gluteus maximus is attached ; the in-
ternal division terminates in front of
the small trochanter. The inferior
divisions terminate at the tuberosi-
ties of the condyles, and enclose be-
tween them a flat triangular surface
of bone, which is free from muscular
attachments, and forms the floor of
the upper part of the popliteal space.
Towards the superior part of the linea
aspera is the foramen for the medullary
vessels, directed upwards into the bone.

The inferior extremity presents two
rounded eminences, the condyles, united
anteriorly, but separated posteriorly by
adeepintercondylar fossa or notch. Their
greatest prominence is directed back-
wards, and their curve, as it increases
towards that part, may be compared
to that of a partially uncoiled piece of
watch-spring. The external condyle is
the broader and more prominent in
front; the internal is the longer and
more prominent inferiorly. One large
articular surface, coated continuously
with cartilage, extends over both con-
dyles, but, opposite the front of the
intercondylar fossa, it is divided by
two slight linear depressions into three
parts, an elevated surface on each side
of the fossa for articulation with the tibia ; and a grooved anterior surface

110 BONES OF THE LOWER LIMB.

for the patella. The patellar surface is of a trochlear form, being
marked by a vertical hollow and two prominent ridges ; the external
portion of this surface is more prominent, and rises higher than the
internal. The tibial surfaces are nearly parallel, except in front, where
the internal turns obliquely outwards to reach the patellar surface.
Above the condyles are two rough tuberosities, one on each side of the
bone, which give attachment to the external and internal lateral liga-
ments of the knee-joint. Between the external tuberosity and the back
part of the external condyle is a smooth groove directed downwards
and forwards, and ending anteriorly in a pit, in which the popliteus
muscle takes origin.

In the female the angle made by the neck of the femur with the shaft is less
obtuse than in the male; and from the greater width of the pelvis, and the
shortness of the limbs, the convergence of the thigh bones inferiorly is more
apparent.

In advanced age the neck comes to be placed at a less obtuse angle than in
middle life, and at last may almost assume a rectangular position in regard to
the shaft. (See Holden’s Osteology.)

THE PATELLA.

The patella, rotwla, or knee-pan, is situated at the front of the knee
joint, is attached inferiorly by a ligament or tendon to the tibia, and

Fig. 98.—Ricnt Parenua. (A.T.) 3

A from before ; B, from behind.

Both views show the lower extremity pointing slightly inwards ;
the posterior view shows the articular cartilaginous surface, divided
by an elevated ridge into a smaller internal and a larger external
part.

may be considered as a sesamoid bone developed in
the tendon of the quadriceps extensor cruris. It is
compressed from before backwards, and has the form
of a triangle with the apex below. Its anterior sur-
face is subcutaneous ; the superior border is broad,
and gives attachment to the extensor muscles ; its
inferior angle, together with a rough depression on
its deep aspect, gives attachment to the ligamentum
patelle. The deep surface, except at the inferior
angle, is coated with cartilage for articulation with the
femur, and is divided by a vertical elevation into two parts, the ex-
ternal of which, the larger, is transversely concave, while the internal
is convex.

B&B

THE TIBIA.

The tibia, or shin bone, is, next to the femur, the longest bone in
the skeleton. It is the anterior and inner of the two bones of the leg,
and alone communicates the weight of the trunk to the foot. It arti-
culates with the femur, fibula, and astragalus.

The swperior extremity is thick and expanded, broader from side to
side than from before backwards, and slightly hollowed posteriorly.
On its superior aspect are placed two slightly concave articular sur-
faces, which sustain the femur. These are the condylar surfaces; they

THE TIBIA. 111

are oval in form, the external being wider transversely, and the
internal longer from before backwards. Between them is an irreg-
ular interval, depressed in front and behind, where it gives attach-

Fig. 99.—Ricut Tipia FRoM BEFORE. (A. 7.) 1

3

1, shaft, and shin or anterior border; 2, inner tube-
rosity ; 3, outer tuberosity ; 4, inner, and 5, outer,
condylar articular surface; 6, crucial spine, with fossa
at its root in front ; 7, anterior tuberosity ; 8, lower
articular surface for astragalus ; 9, malleolus internus.

ment to the crucial ligaments and semilunar
cartilages of the knee joint, and elevated
in the middle, where is formed the, spine.”
The summit of the spine presents two pro-
minent tubercles, formed by the prolonga-
tion upwards on its sides of the margins
of the condylar portions; the outer being
turned slightly forwards, and the inner
slightly backwards. On the sides of the
upper extremity of the bone are two rounded
eminences, the external and internal tuber-
osities ; the outer one of these, somewhat
smaller than the other, is marked posteriorly
by a flat surface which articulates with the
fibula, while the inner presents a groove for
the insertion of the semi-membranosus mus-
cle. Lower down, in front, is situated the
anterior tuberosity or tubercle, rough inferiorly,
where it gives attachment to the ligamentum
patella, and smooth above, where it is
covered by a synovial bursa.

The shaft of the tibia is three-sided, and
diminishes in size as it descends for about
two-thirds of its length, but increases some-
what towards its lower extremity. The
internal surface is convex and subcutaneous,
except at the upper part where it is crossed
by the tendons of the sartorius, gracilis, and
semitendinosus muscles. It is separated from
the external surface by a _ sharp subcu-
taneous, slightly sinuous crest, the shin ridge,
which descends from the anterior tuberosity,
and is smoothed away in the inferior third
of the bone. The external surface is slightly
hollowed in the larger part of its extent,
where it gives origin to the tibialis anticus muscle ; but beneath the
point where the crest disappears it turns forwards, becomes convex, and
is covered by the extensor tendons. The posterior surface is traversed
obliquely in its upper third by the popliteal line—a rough mark which
extends upwards and outwards to the external tuberosity, giving attach-
ment to the soleus muscle, and separating a triangular area, in which
the popliteus muscle lies, from the space below, which gives origin to the
flexor longus digitorum and tibialis posticus. The posterior surface is

112 BONES OF THE LOWER LIMB.

separated from the internal by a smooth rounded border, and from the
external by a sharp ridge, inclined forwards above, to which the inter-
osseous membrane is attached. Near the popliteal line is a large me-

Fig. 100.—Rieut Trpta From BEHIND. (A.T.) 4 Fig. 100.

6, and 9, as in the preceding figure ; 2’, groove behind
the internal tuberosity for the tendon of the semi-mem-
branosus muscle ; 10, inclined articular facet below and
behind the outer tuberosity for the head of the fibula ;
11, oblique line of tibia, above which is the triangular
popliteal surface ; 12, nutritious foramen directed
downwards ; 13, triangular rough surface for the lower
interosseous ligament, and small cartilaginous surface
below it for articulation with the fibula ; 14, below a
slight groove marking the place of the flexor longus
pollicis muscle ; 15, below the groove of the tendons of
the flexor communis digitorum and tibialis posticus
muscles.

dullary foramen, directed downwards into
the interior of the bone.

The inferior extremity, much smaller than
the superior, is expanded transversely, and
projects downwards on its inner side, so as
to form a thick process, the internal malleo-
lus. Inferiorly it presents for articulation
with the astragalus a cartilaginous surface,
which is quadrilateral, concave from before
backwards, and having its posterior border
narrower and projecting farther downwards
than the anterior; internally the cartila-
ginous surface is continued down in a
vertical direction upon the internal malleo-
lus, clothing its outer surface somewhat
more deeply in front than behind. The
external surface, slightly concave, is rough
superiorly for ligament, and smooth below
for articulation with the fibula. The pos-
terior surface of the internal malleolus is
marked by a double groove for the tendons
of the tibialis posticus and flexor longus
digitorum, and more externally by a slight
depression where the flexor longus pollicis
lies ; the inner surface of the malleolus is
subcutaneous.

The tibia is slightly twisted, so that when
the internal malleolus is directed inwards,
the internal tuberosity is inclined backwards.

THE FIBULA.

The fibula, or peroneal bone, is situated at the outer side of the leg:
it is nearly equal to the tibia in length, but is much more slender. Its
inferior extremity is placed a little in advance of the superior; and
its shaft is slightly curved, so as to have the convexity directed back-
wards, and, in the lower half, slightly inwards towards the tibia.

THE FIBULA. 118

The superior extremity, or head, somewhat expanded, presents a small
oval cartilaginous surface looking upwards and inwards, which articu-
lates with the external tuberosity of the tibia, and externally to this a

BEFORE. (A. T.) 4

1, shaft showing the oblique grooves of the peronei
muscles on the outer anterior surface ; 2, head ; 3, its
projection, giving insertion to the tendon of the biceps
femoris ; 4, malleolus externus or lower end, the figure
is placed opposite its anterior or oblique edge ; above this
is seen the triangular subcutaneous surface of the bone.

Fig. 101.—Ricur FrsvzA FROM THE OUTSIDE AND Fig. 101. Fig. 102.

5 “?

Fig. 102.—Riegut FisvLA FROM THE INSIDE AND
BEHIND. (A. 7.) 4

5, the oblique surface of articulation with the tibia
superiorly ; 6, points to the internal or interosseous
ridge ; 7, the triangular rough surface for the lower
interosseous ligament ; 8, the external malleolar surface
for articulation with the astragalus ; 9, groove behind
the malleolus externus for the tendons of the peronei
muscles ; at a little distance below 6, the nutritious
foramen.

rough prominence directed upwards, to
which the tendon of the biceps muscle is at-
tached : its external surface is subcutaneous ;
the rest is rough for ligaments.

‘The inferior extremity, or external malleo-
lus, is larger than the head of the bone, and
longer and more prominent than the internal
malleolus ; internally it forms the outer limit
of the ankle joint, and presents a triangular
smooth surface for articulation with the as-
tragalus, bounded posteriorly by a rough
depression where the transverse ligament is
attached : its anterior border, after project-
ing rather abruptly forwards, slopes down-
wards and backwards ; its posterior border
presents a shallow groove traversed by the
tendons of the peronei muscles ; while
externally it is convex and subcutaneous,
and a triangular subcutaneous surface is
continued up from it for an inch or two on
the shaft.

The shaft is irregularly three-sided and
twisted. One surface, from which the pe-
ronei muscles take origin, looks forward at the »
commencement, then turning outwards and backwards, is continued
behind the subcutaneous space of the lower end to the groove behind the
malleolus. Another surface, looking backwards in the upper half of its
extent, winds inwards and terminates above the articular surface of the
malleolus ; near its upper end this surface is rough, giving attach-
ment to the soleus muscle, and in the rest of its extent it is occupied
by the flexor longus pollicis. The remaining part of the surface of
the bone, internal, turns forward inferiorly, and terminates on the

anterior margin of the malleolus ; it is divided by a longitudinal line,
VOL, I, I

114 BONES OF THE LOWER LIMB.

the interosseous ridge, into a posterior and upper part, which gives
origin to the tibialis posticus, and an anterior and lower part, from
which arise the long extensors of the toes and the peroneus tertius, the
interosseous membrane being attached to the line between these sur-
faces. About the middle of the posterior surface is the medullary
foramen directed downwards into the bone.

THE TARSUS.

The tarsus is composed of seven bones, viz., the calcaneum, astragalus,
cuboid, scaphoid, and three cuneiform.

The caleaneum, or os calcis, is the largest bone of the foot. Pro-
jecting downwards and backwards, it forms the heel. Above it articu-
lates with the astragalus, and in front with the cuboid bone. Its principal
axis extends forwards and outwards from its posterior extremity to
the cuboid bone.

The large posterior extremity, or tuber calcis, presents inferiorly two
tubercles, which rest upon the ground, and the internal of which is the
larger : the rest of its surface, looking backwards, is divided into a lower

Fig. 103.—Rieut Foot, VIEWED FROM ABOVE, SHOWING
its DorsaL aspect. (A. T.) 3

a, scaphoid bone; 20, astragalus ; c, os calcis; d, its
great tuberosity ; ¢, internal or first cuneiform ; f, middle
cuneiform ; g, external cuneiform ; , cuboid bone. I to
V, the series of metatarsal bones ; 1, 3, first and terminal
phalanges of the great toe; 1, 2, 3, first, second, and
terminal phalanges of the second toe.

eart which receives. the attachment of the tendo
Achillis, and an upper part smooth and _ less
prominent, separated from that tendon by a
synovial bursa. ‘The part in front of the tuber
forms a slightly constricted neck. The internal
surface of the bone, traversed by the plantar
vessels and nerves and the flexor tendons, is
deeply concave, and its concavity is surmounted
in front by a flattened process, the susfentacu-
lum tali, which projects inwards near the an-
terior extremity of the bone in a line with its
upper surface, and presents inferiorly a groove
occupied by the tendon of the flexor longus
pollicis. The superior surface presents two
articular facets for the astragalus : the anterior
of these is placed over the sustentaculum, and
is flat; the other, external and posterior to this,
and larger, is separated from it by a rough
furrow, giving attachment to the interosseous ligament, and is con-
vex from without inwards and backwards. In front of this latter
facet is a rough depression, from which the extensor brevis digitorum
takes origin. The anterior extremity articulates by a surface slightly
concave in the vertical and convex in the transverse direction, with
the cuboid bone, and internal to this, in front of the sustentaculum

THE TARSUS—ASTRAGALUS. 116

tali, it gives attachment to the inferior calcaneo-scaphoid ligament.
The inferior surface, projecting in a rough anterior tubercle, gives attach-
ment to the calcaneo-cuboid ligaments. The external surface is sub-
cutaneous, and on the whole smooth, but presents in its fore-part
a slight ridge, and below it, superficial grooves traversed by the tendons
of the peronei muscles.

The astragalus, or /alus, irregular in form, receives the weight of the
body from the leg. It articulates with the tibia and fibula above, the
os calcis below, and the scaphoid in front. Its longest axis is directed
forwards and inwards. Its convex anterior extremity is called the head,
and the circular groove behind it the neck. The superior articular sur-

Fig. 104.—Ricut Foot vreEWED FROM BELOW, SHOWING Fig. 104.
THE PuantTarR Asprctr. (A. T.) 3

The indications are the same as in the preceding figure ;
the middle and external cuneiform bones are not lettered ;
the sesamoid bones are not represented ; they will be seen
in the view of the articulations of the foot.

face, placed behind the neck, consists of a mid-
dle and two lateral parts. The middle part,
looking upwards to the tibia, is convex from
before backwards, broader in front than behind,
with its outer,margin higher and longer than the
inner, and curved, while the inner is straight.
The inner lateral part is narrow, and articulates
with the internal malleolus ; the outer lateral
part, much deeper, articulates with the external
malleolus. Inferiorly, there are two smooth sur-
faces, which articulate with the caleaneum. The
posterior of these, the larger, concave from
within outwards and forwards, is separated by
a rough depression for the interosseous liga-
ment from the flat anterior surface, which rests
on the sustentaculum tali. The anterior margin
of this surface is continuous with the rounded
surface of the head, which articulates with
the scaphoid bone. The posterior border of the
bone hes behind the sustentaculum tali, and like
that process, is grooved by the tendon of the flexor longus pollicis.

The scaphoid or navicular bone is placed at the inner side of the foot
between the astragalus and cuneiform bones. It is short from behind
forwards, and broad from side to side. Jt presents posteriorly an
articular concavity for the head of the astragalus, and anteriorly a
convex surface divided by two lines converging below, into three facets
which articulate respectively with the three cuneiform bones. On its
outer side, in some instances, is a small smooth surface, by which it is
articulated to the cuboid bone. Its superior and inferior surfaces are
rough, and on its inner border, directed downwards, is a prominent
tubercle to which the tendon of the tibialis posticus muscle is attached.

The cuneiform, or wedge-shaped bones, three in number, are dis-
tinguished numerically according to their order from within outwards.
They intervene between the scaphoid bone and the three inner metatarsa

IZ

116 BONES OF THE LOWER LIMB.

bones, and present anteriorly and posteriorly smooth surfaces for articula-
tion with those bones. The first or internal cuneiform bone is the largest ;
it is narrow above, and thick and rough towards the sole; its dorsal
surface looks inwards and upwards, and is marked by an oblique
descending groove, in which the tendon of the tibialis anticus lies ;
its external surface, concave and rough inferiorly, is smooth and arti-
cular above. The second and third, or middle and external, cuneiform
bones present each a quadrangular surface superiorly, and a narrower
rough edge below, contributing thus to form the transverse arch of the
foot. The proximal ends of the three bones are in the same transverse
line; but as the middle bone is shortest, the internal and external
project forwards, so as to articulate laterally not only with the sides of
that bone, but also with the base of the second metatarsal bone, which
is inserted between them. The outer side of the third cuneiform
articulates by a smooth flat surface with the cuboid, and by a small
narrow facet (sometimes absent) with the fourth metatarsal bone.

The cuboid bone is situated at the outer side of the foot, between the
calcaneum and the fourth and fifth metatarsal bones. It deviates from
the cuboid form and becomes rather pyramidal, by the sloping of four of
its surfaces towards the smaller external border. The posterior carti-
laginous surface articulates with the os calcis: the anterior surface, also
covered with cartilage, is divided into an internal quadrilateral and an
external triangular facet, articulating with the fourth and fifth metatarsal
bones. On the internal aspect, in the middle, and touching its superior
border. is a smooth surface, which articulates with the external cunei-
form bone, and behind this, in some instances, a smaller surface arti-
culating with the scaphoid, while the remainder is rough for ligaments.
The external border presents a smooth vertical groove, in which the
tendon of the peroneus longus lies ; and the inferior surface is traversed
obliquely near its anterior margin by a continuation of the same groove ;
behind this there is a thick ridge, which, with the rest of the inferior
surface, gives attachment to the calcaneo-cuboid ligaments. The supe-
rior surface, looking outwards and upwards, is on the whole even, but
rather rough.

THE METATARSUS.

The five metatarsal bones are distinguished by numbers, according
to their position from within outwards.

They resemble the metacarpal bones of the hand in being shafted
bones, slightly convex from behind forwards on the dorsal aspect, and
having irregularly shaped proximal extremities, three-sided shafts, and
rounded heads which articulate with the phalanges. The first meta-
tarsal bone is much thicker and more massive, though shorter than
any of the rest. The others diminish in length from the second to the
fifth.

The proximal extremities resemble those of the metacarpal bones
exactly as regards the number of bones with which each articulates.
The first articulates with one bone, the internal cuneiform ; the second
with four bones, viz., the three cuneiform and the third metatarsal; the
third with three bones, viz., the external cuneiform and the adjacent
metatarsals ; the fourth with four bones, viz., the cuboid, external cunei-
form, and the adjacent metatarsals; the fifth with two bones, viz., the
cuboid and the fourth metatarsal. The fourth, however, is sometimes con-

THE PHALANGES. 117

nected with only three bones, its facet for articulation with the external
cuneiform being absent. The tarsal extremity of the first metatarsal
bone presents a slightly concave articular surface, and is broad below
and narrow above. That of the fifth presents externally a large rough
tuberosity which projects beyond the other bones at the outer side of
the foot ; and the line of its articulation with the cuboid bone is go
oblique that, if prolonged inwards, it would reach the digital end of
the first metatarsal bone. The tarsal ends of the remaining three bones
are broad and flat above, rough and narrower below, and by their wedge-
like form assist in producing the transverse arch of the foot.

The shafts present in the greater part of their extent a prominent
border looking upwards, which in the middle three projects between
the dorsal interosseous muscles on each side.

The heads, or distal ends are smaller than the proximal, and are
marked on their sides by depressions and tubercles. Their articular sur-
faces, smooth and convex, are prolonged on the inferior aspect, where
they terminate in bifid margins. That of the first metatarsal bone pre-
sents inferiorly a ridge in the middle, with grooved depressions placed
one on each side and corresponding to the position of the sesamoid bones.

THE PHALANGES.

The phalanges of the toes correspond so nearly in general conforma-
tion with those of the fingers that it will only be necessary in this place
to state the points in which they differ from the latter.

The phalanges of the four outer toes are much smaller than the
corresponding phalanges of the hand; but those of the great toe are
larger than those of the thumb. ‘The shafts of the first row of pha-
langes in the four outer toes are compressed laterally and narrowed
in the middle ; those of the second row, more especially the fourth and
fifth, are very short, and consist of little beyond what is necessary to
unite their articular extremities. The last two phalanges of the little
toe are in adults not unfre quently connected by bone into one piece.

SESAMOID BonEs.—Two sesamoid bones lie side by side in the
plantar wall of the first metatarso-phalangeal joint, and glide in the
erooves on the head of the first metatarsal bone. Small sesamoid
bones sometimes occur in the corresponding joints of the other toes.

THE BONES OF THE FOOT AS A WHOLE.

The foot is narrowest at the heel, and as it passes forwards becomes
broader as far as the heads of the metatarsal bones. The posterior ex-
tremity of the caleaneum is inclined slightly inwards. The astragalus,
overhanging the sustentaculum tali, inclines inwards from the caleaneum
so much that its external superior border is directly over the middle
line of the calcaneum, and hence the internal malleolus appears more
prominent than the external. The foot is arched from behind forwards,
the posterior pier of the arch being formed by the heel, the anterior
by the balls of the toes. The arch, indeed, may be considered as
double in front, with a common support behind. The internal division
of the arch is that which bears the greater part of the weight of the
body, and is most raised from the ground ; it consists of the calcaneum
in its posterior two-thirds, the scaphoid and cuneiform bones, and the
three inner toes; the outer arch is formed by the calcaneum in its

118 BONES OF THE LOWER LIMB.

whole length, the cuboid bone, and the fourth and fifth toes, a great
part of which rests upon the ground in standing. Besides being
arched longitudinally, the foot presents likewise a transverse arch
formed behind by the cuboid and three cuneiform bones, and in front
by the metatarsal bones.

OSSIFICATION OF THE BONES OF THE PELVIS AND LOWER LIMB.

Os innominatum.—The innominate bone is formed from the three principal
pieces previously mentioned, viz., the ilium, ischium, and os pubis, and from
various others of an epiphysial nature. Ossification commences in the cartilage
of the ilium a little later than in other large bones, bone beginning to be depo-
sited above the sciatic notch in the 8th or 9th week. This is followed by similar
deposits in the thick part of the ischium below the acetabulum in the 3rd
month, and in the ascending ramus of the pubis in the 4th or 5th month. At

Fig. 105.

Fig. 105.—Ossrrication oF THE Os Iynominatum (R. Quain).

A, the condition of the bone at birth. Bone has spread from three nuclei into the
ilium, ischium, and pubis, which meet in the cartilage of the acetabulum.

b, from a child under six years of age. The rami of the ischium and pubis are farther
ossified, but still separate.

C, a bone of two or three years later, in which the rami are united.

D, the bone of the right side from a person of about twenty years. Union has taken
place in the acetabulum, and the additional epiphyses are seen in the crest of the ilium,
the anterior inferior spine, the ischial tuberosity, and the margin of the symphysis pubis.

In A, Band ©, 1, ilium ; 2, ischium ; 3, pubis ; below D, 4, separated v-shaped piece
formed of several fragments which be gin to ossify about the 14th year, and often unite
into this form before the completion of the acetabulum ; 5, epiphysis of the crest ; 6, that
of the tuberosity of the ischium ; 7, that of the symphysis pubis ; 8, that of the anterior
inferior spine of the ilium.

birth the greater part of the acetabulum, the crest of the ilium, the tuberosity
and ramus of the ischium, the body and descending ramus of the pubis are still
cartilaginous ; ossification, however, from the three primary centres has extended
into the margin of the acetabulum. In the 7th or Sth year the rami of the ischium
and pubis become completely united by bone. The parts which meet in the
acetabulum are still separated by a tri-radiate strip of cartilage, which from
its shape has been called the Y cartilage. This cartilage begins to be ossified
from one or more centres about the age of ‘puberty, and the intermediate hone
or epiphysis so formed is united to the neighbouring parts about the 17th or
18th year. Epiphyses are likewise formed in the cartilage of the crest of the

OSSIFICATION OF THE FEMUR, 119

ilium, the tuberosity of the ischium, the anterior inferior spine of the ilium,
and the symphysis pubis. These begin to ossify soon after puberty, and unite
with the main bone from the 23rd to the 25th year.

The pelvis of the foetus and young child is of very small capacity propor-
tionally to the size of the body, and those viscera which are afterwards contained
for the most part in the true pelvis occupy a part of the abdominal cavity. The
inclination of the pelvis is considerably greater in early life than in the adult.

The femur is developed from one principal ossific centre for the shaft
which appears in the 7th week, and from four epiphyses, the centres for which
appear in the following order ;—A single nucleus for the lower extremity appears
several weeks before birth, one for the head appears in the Ist year, one for the

Fig. 106.

Fig. 106.—OssrricaTion oF THE Femur (R. Quain.)

A, from a foetus under eight months; the body is osseous, both ends are carti-
laginous.

B, from a child at birth, showing a nucleus in the lower epiphysis.

C, from a child of about a year old, showing a nucleus in the articular head.

D, at the fifth or sixth year. Ossification has extended from the shaft into the neck,
and a nucleus has appeared in the great trochanter.

E, near the age of puberty, showing more complete ossification and a nucleus in the
lesser trochanter.

1, shaft; 2, lower extremity ; 3, head; 4, great trochanter ; 5, small trochanter.

C, D, & E are represented considerably, A and B very little, under the natural size.

great trochanter in the 4th year, and one for the small trochanter in the 13th or
14th year. These epiphyses become united to the shaft in an order the reverse
of that of their appearance. The small trochanter is united about the 17th year,
the great trochanter about the 18th year, the head from the 18th to the 19th year,
and the lower extremity soon after the 20th year. The neck of the femur is
formed by extension of ossification from the shaft

The patella is formed in the 3rd month by a deposit of cartilage in the tendon
of the quadriceps extensor cruris muscle. In this cartilage ossification begins
from a single centre during the third year, and is completed about the age of
puberty.

The tibia and fibula each present, besides the principal centre of ossification
for the shaft, a superior and an inferior epiphysis. In the tibia the centre for
the shaft appears in the 7th week; that for the upper extremity, including the
anterior and lateral tuberosities, appears most frequently before, but sometimes
after birth ; and that for the inferior extremity and internal malleolus appears

120 BONES OF THE LOWER LIMB.

Fig. 107.

Fig. 107.—OsstFrcaTIon oF TuE Trera (R. Quain).

A, from a foetus some weeks before birth ; the shaft is ossified ; the ends are cartila-
ginous.

B, from a child at birth, showing the commencement of a nucleus in the upper epiphysis.

C, at the third year, showing the nucleus of the lower epiphysis.

D, at about eighteen or twenty years, showing the united condition of the lower epiphysis,
while the upper remains separate. The upper epiphysis is seen to include the anterior
tuberosity.

E shows an example of a separate centre for the anterior tuberosity.

1, shaft ; 2, superior epiphysis ; 2*, separate centre for the anterior tuberosity ; 3,
inferior epiphysis.

Fig. 108.

Fig. 108.—Osstrrcation oF THE Frevna (R. Quain).

A, from a child at birth. The shaft ossified ; the ends cartilaginous.

B, from a child of two years, showing a nucleus in the lower epiphysis.

C, from a child of about four years, showing the nucleus of the upper epiphysis ; the
lower ought to have been shown as more advanced.

D, from a person of about twenty years, in which the lower end is complete, but the
upper epiphysis is still separate.

1, shaft ; 2, lower epiphysis ; 3, upper epiphysis.

OSSIFICATION OF THE BONES OF THE FOOT. 121

Fig. 109.

Fig. 109.—Osstrrcation or THE Bones or THE Foor (R. Quain).

__A, right foot of a foetus of six months. The metatarsal bones and digital phalanges
have each their shafts ossified from their primary centres ; the tarsus is wholly cartila-
ginous, excepting the os calcis, in which the nucleus of bone has just appeared.

B, foot of a foetus of from seven to eight months. The astragalus shows an osseous
nucleus.

G, from a child at birth ; the cuboid has begun to ossify.

D, about a year old, showing a nucleus begun in the external cuneiform.

E, in the third year ; ossification has reached the internal cuneiform.

F, between three and four years old, showing ossification in the middle cuneiform and
scaphoid bones, and in the epiphyses of the metatarsal bones and phalanges.

G, about the age of puberty. Ossification is nearly complete in the tarsal bones ; an
epiphysis has been formed on the tuberosity of the os calcis, and the epiphyses of the
metatarsal bones and phalanges are shown separate.

1, nucleus of the os calcis ; 1* in G, the epiphysis of the os calcis ; 2, nucleus of the
astragalus ; 3, of the cuboid-; 4; of the external cuneiform ; 5, of the internal cuneiform ;
G6, of the seaphoid ; 7, of the middle cuneiform ; 8, metatarsal bones ; 8*, distal epiphyses
of the four metatarsal bones ; 8’, proximal epiphyses of the first ; 9, first range of digital
phalanges ; 9*, proximal epiphyses of the four outer of these phalanges ; 9’, that of the
first phalanx of the great toe ; 10, second range of phalanges ; 10*, the epiphyses of these
phalanges ; 10’, epiphysis of the terminal phalanx of the great toe ; 11, four terminal
phalanges ; 11*, their epiphyses.

s

122 MORPHOLOGY OF THE BONES OF THE LIMBS.

in the 2nd year. The anterior tuberosity is occasionally formed from a separate
centre. The lower epiphysis and shaft unite in the 18th or 19th year, the upper
epiphysis and shaft unite in the 2lst or 22nd year. In the fibula the centre for
the shaft appears rather later than in the tibia; that for the lower extremity
appears in the 2nd year, and that for the upper, unlike that of the tibia, not till
the 3rd or 4th year. The lower epiphysis and shaft unite about the 21st year,
the upper epiphysis and shaft unite about the 24th year.

The tarsal boncs are ossified in cartilage each from a single nucleus, with the
exception of the os calcis, which in addition to its proper osseous centre, has an
epiphysis upon the upper part of its posterior extremity. The principal nucleus
of the os calcis appears in the 6th month of foetal life; its epiphysis begins to
be ossified in the 10th year, and is united to the tuberosity in the 15th or 16th
year. The nucleus of the astragalus appears in the 7th month; that of the
cuboid at birth; that of the external cuneiform in the Ist year; that of the
internal cuneiform in the 3rd year; that of the middle cuneiform in the 4th
year ; and that of the scaphoid in the 4th or 5th year.

The metatarsal bones and phalanges agree respectively with the corresponding
bones in the hand, in the mode of their ossification. Hach bone is formed from
a principal piece and one epiphysis; and while in the four outer metatarsal bones
the epiphysis is at the distal extremity, in the metatarsal bone of the great toe
and in the phalanges it is placed at the proximal extremity. In the first meta-
tarsal bone there is also to be observed, as in the first metacarpal (see ossification
of that bone), a tendency to the formation of a second or distal epiphysis. (A.
Thomson.) In the metatarsal bones the nuclei of the shafts appear in the 8th
or 9th week. The epiphyses appear from the 3rd to the 8th year, and unite with
the shafts from the 18th to the 20th year. The nuclei of the shafts of the
phalanges appear in the 9th or 10th week. The epiphyses appear from the 8th to
the 10th year, and unite with the shafts fromthe 19th to the 21st year.

MORPHOLOGY OF THE BONES OF THE LIMBS.

Relation to the Axial Skeleton.—Anatomists have generally agreed to look
upon the relation which the bones of the limbs bear to the rest of the skeleton
as that of appendages to the trunk, hence their distinction as appendicular parts
of the awial skeleton ; and most are also disposed to regard these appendages as
similar radiations or extensions from one or more of the vertebral segments in two
determinate situations of the trunk. But opinions are still divided as to the typical
number of the vertebral somatomes which are involved, and as to the exact nature
of the parts which form the radiations, The existence in both of a supporting
arch in relations somewhat resembling those of pleurapophyses or ribs, and the
division of this arch at the joints of the limbs (shoulder and hip joints) into an
upper or dorsal and a lower or ventral section is easily recognised ; the dorsal
being firmly attached to the side of the sacrum in the lower limb, while in the
upper, the ventral part of the arch abuts on the sternum. But it does not appear to
be yet determined, even in the case of the pelvic arch, what is the exact nature of
the lateral mass of the sacrum, and in both limbs it is still doubtful what is the
precise homological relation of the arch to the vertebre. The fact, however,
that a quinquifid division of the peripheral parts of both limbs is constant in
man anda certain number of animals, and that in no animals above fishes is
there a greater number of elements than five, while in many animals some of the
elements may be absent or abortive, together with the remarkably regular passage
of a certain number of spinal nerves from the trunk to the limb, of which five
are of considerable size in man and those animals possessing the limb elements
complete, appears favourable to the view that both limbs have prolonged into
them the elements of five vertebral segments, and it is generally held that these
elements follow each other in a similar order in the two limbs from the cephalic
to the caudal part of the vertebral axis, so that the pollex and radial elements
occupy the cephalic side of the upper, while the hallux and tibia take the same
place in the lower limb. (See Owen “ On the Nature of Limbs,” Goodsir “ On
the Morphological Constitution of Limbs,’ in Edin. New Philos. Journ., 1857.)

COMPARISON OF SHOULDER AND PELVIC GIRDLES. 123

Homological Comparison of Upper and Lower Limbs.— A _ certain
anatomical correspondence between the upper and lower limbs, which is apparent
to common observation, is admitted in even a fuller degree by most scientific
anatomists as the result of a careful comparison of the form, structure, and
relations of their bones, as well as of their other parts. But very different views

have been taken of the nature and extent of the comparison which may be made
’ between them. Thus Vicq d’Azyr compared the bones of the upper limb of one
side of the body to the bones of the lower limb of the other; and Bourgery and
Cruveilhier regarded the upper end of the tibia as homologous with that of the
ulna, while they compare its lower end to that of the radius. But all such
fanciful views have now yielded to the fuller appreciation of homological
correspondence which has resulted from a more careful comparison of structure
in a wide series of animals, and the study of their transformations in embryonic
development ; and thus the general conclusion has been formed, that the thoracic
and pelvic limbs are constructed on the same general type in man and animals,
both as regards the attaching girdles of the shoulder and pelvis, and in the
three several sections of which each limb is composed. There are, however,
certain modifications of that general plan, leading to considerable differences in
the form, size, and number of the individual parts in different animals, which
appear to be in a great measure related to the different uses to which the upper
and lower limbs are respectively applied ; as, for example, in the upper limb of
man, the breadth of the shoulders, caused by the interposition of the clavicle,
the greater extent of motion in the shoulder joint, the eversion of the humerus,
and the forward flexed attitude of the elbow-joint, the arrangements for pro-
nation and supination by rotation of the radius and hand, and the opposability
of the thumb, all have reference to the freedom, versatility, and precision
of the movements of the upper limb as an organ of prehension and touch ; while
in the lower limb, the comparatively fixed condition and arched form of the
pelvic girdle, the greater strength of the bones, the close-fitting of the hip-joint,
the inversion of the femur, the backward flexure of the knee-joint, the arched
form of the foot, and non-opposability of the great toe, have all manifest relation
to the support of the trunk and pelvis, and their movements upon the lower
limbs. In the lower animals, greater modifications in the form of both limbs are
to be observed, obviously adapted to their different functions in each case.

Without attempting to follow out this subject by any detailed reference to
comparative anatomy or development, it may be useful to state here shortly the
more probable conclusions which have been formed by the most recent inquirers
with respect to the homological correspondence of the several parts of the upper
and lower limbs.*

Shoulder and Pelvic Girdles. With respect to the attaching bones of the
two limbs, it is generally held that the blade of the scapula corresponds with the
ilium, each of them forming the dorsal section of their respective arches ; and
the greatest difference between them consisting in the scapula being entirely free
from bony articulation with the vertebral column, and capable therefore of
considerable motion, while the ilium is firmly jointed to the lateral mass of the
sacrum. The ventral part of the shoulder-girdle, completed by the articulation
of the clavicles with the sternum, presents no doubt at first sight some similarity
to the meeting of the ossa pubis at the symphysis: and thus at one time the
clavicle and the pubis were looked upon as homologous bones. But the fuller
knowledge of comparative anatomy has more recently led to the adoption of a
different view, according to which it appears more probable that the pubis repre-
sents rather the epicoracoid bone of the Monotremata and of Reptiles, while, as
before believed, the coracoid process of man, originally separate, and typically a
distinct bone, is represented in the pelvic girdle by the ischium. Thus, then, it
appears that the clavicle is not repeated in the lower limb girdle; and in the
place of the very imperfect coracoid process of man and most mammals, there

* It is right to mention that, while in the comparison here given most British and
European authors coincide, opinions widely different from these are held by several com-
parative anatomists of distinction in America, among whom may be mentioned Agassiz,
Wyman, Wilder, and Coues.

124 MORPHOLOGY OF THE BONES OF THE LIMBS.

exists in the lower limb a double ventral branch (pubis and ischium) most
probably corresponding morphologically to the epicoracoid and coracoid of the
Monotremata and Reptiles. The clavicle has, indeed, by some been held to be
represented by Poupart’s ligament, but it seems on the whole more probable that
there is no exact homologue of the clavicular arch in the lower limb. The
marsupial bone of the pouched mammals does not represent the clavicle, but lies
in the situation of the upper or mesial pillar of the external inguinal aperture.

With regard to the comparison to be established between the individual parts
of the scapula and ilium, still greater difficulty prevails than in the general deter-
minations before mentioned. When looked at only in man, the iliac fossa appears
at first sight to be the most obvious representative of the subscapular fossa;
while the dorsum ilii seems to contain within its limits parts corresponding to
both the supra- and infraspinal fosse. But when our observation extends to a
series of different animals, this view loses its apparent probability, and a different
mode of comparison is forced upon us. It then appears obvious that the iliac
fossa does not at least correspond to the subscapular ; but the full determina-
tion of the homologies of the different parts of the scapula and ilium, is one of
the most difficult parts of this intricate subject. Two different views have lately
been brought forward, the one supported by Flower, according to which the
scapula and ilium are supposed to have undergone rotation with reference to
the axis of the limbs in different directions, the scapula backwards, the ilinm
forwards, in such a manner that the prescapular fossa (supraspinous of man)
corresponds to the sacral surface of the ilium, the postscapular (infraspinous of
man) to the iliac fossa or surface, and the subscapular to the gluteal. (See
Flower's “ Osteology of the Mammalia,” and ‘*‘ On the Correspondence between
parts composing the shoulder and the pelvic girdle of the Mammalia,” Journ. of
Anat., vol. iv., 1870.) According to the other view maintained by Humphry,
the prescapular and iliac fosse are regarded as homologous, and the post-
scapular fossa as corresponding with the dorsum ilii or gluteal surface, the sub-
scapular surface being represented by the sacral and the true pelvic surfaces of
the ilium. (Humphry, “ Comparison of the Shoulder Bones and Muscles with
the Pelvic Bones and Muscles,” Journ. of Anat., vol. v. : see also Mivart, in Linn.
Soc. Trans. 1866, and Rolleston, in the same, 1869). In the more developed
forms of the scapula and ilium,in which the muscular fosse are of large extent,
it is almost impossible to trace the relations now referred to; but in the com-
parison of the simple forms of these bones which belong to some animals with
those of others throughout the series, resemblances are perceived which give to
the views of Flower the greatest share of probability. In such simpler forms of
scapula and ilium these bones may be described as three-sided prismatic rods, in
which an internal surface is separated from two external surfaces by anterior
and posterior ridges, and the two external surfaces are divided by an external
ridge which descends from the dorsal extremity of the bones to the cavity of the
joints. It is in this external ridge, glenoid in the scapula and cotyloid in the
ilium, and which includes in both the attachment of the great extensor muscle of
the limb, that the key to the homologies of the bones is probably to be found.
Further observations, especially on the disposition of the muscles, are necessary
to determine this question satisfactorily.

Bones of the Limbs.—In making the comparison of the bones composing the
limbs themselves, it may be proper to revert to the simpler, relations subsisting
between the limbs and the trunk or vertebral axis of the body in earlier
embryonic life, and to remind the reader that there is a determinate and similar
position in which the elements of the limb-forming parts are developed from the
side of the vertebral stem or trunk (Humphry). In the very earliest stage, while
the embryo still occupies the prone position in the blastoderm, the limbs may be
said to bud out laterally from the dorsal plates as flattish semilunar flaps, so that
they present a dorsal and a ventral surface, coinciding with these respective
surfaces of the trunk: but in the next stage, when the limbs come to be folded
against the body in the ventral direction, although the original relation to the
trunk is undisturbed, their axes have now come to lie nearly perpendicularly to the
transverse plane of the vertebral axis, and the position of the limbs is such that in
each there is one border which looks towards the head, and another which looks

COMPARISON OF THE ARM AND LEG BONES. 12é

Figs. 110 & 111.—Sxurcn
OF THE BONES OF THE
TuoRAcIG AND PELYVIC
Limes SO PLACED AS TO
SHOW CORRESPONDING
PARTS IN BOTH. (A.
LHS) es

6

The preaxial borders of
both limbs are towards
the reader’s right hand,
and the dorsal or true ex-
tensor surfaces are shown
throughout the whole ex-
tent of the limbs. The
somewhat artificial repre-
sentation given in these
figures cannot be obtained
from a single view of the
specimens in one position,
but it is easily brought out
by slightly shifting the
bones or changing the
point of view. The hu-
meral tuberosities are
separated so as to show
them on the borders of the
bone. Fig. 110, Thoracic
Limb; ssp, supraspinous or
preseapular fossa ; isp, in-
fraspinous or postscapular
fossa ; ssc, a small part of
subscapular fossa ; bs,
base of scapula ; sa, su-
perior angle ; za, inferior
angle ; sp, spine; ac,
acromion ; cr, coracoid
process ; gb, glenoid bor-
der with place of attach-
ment of triceps muscle ;
ge, glenoid cavity ; h,
humerus, preaxial border ;
tm, large or preaxial tuber-
osity ; tp, small or post-
axial tuberosity ; ¢7", radial
condyle ; cu, ulnar con-
dyle ; 7, radius ; 7, ulna ; 0,
olecranon ; px, pollex side ;
pi, pisiform and postaxial
side of hand. Fig. 111,
Pelvic Limb: ss, sacral
surface of ilium ; 2/, iliac
fossa ; di, a small part of
dorsum ilii or gluteal sur-
face ; ze, crest of ilium ;
as, anterior superior
spinous process ; zp, ilio-
pectineal line; ep, pec-
tineal eminence ; 7s, in-
ferior spine and attach-
ment of rectus muscle ;
cc, cotyloid cavity ; sp,
symphysis pubis ; sc,
ischium ; jf, femur, its

bo
1

Fig. 111. Fig. 110.

preaxial border ; trp, lesser or preaxial trochanter ; trm, greater or postaxial trochanter ;
ct, tibial condyle ; cf, fibular condyle; p, patella ¢, tibia; éf, tibial tuberosity ; St,
fibula; Aw, hallux ; ca, calcaneal tuberosity.

126 MORPHOLOGY OF THE BONES OF THE LIMBS.

+owards the tail. To these borders of the limbs, Huxley and Flower have given
the names of preaxial and postaxial respectively, as indicating their position
before and behind the axis of the limbs. When at a somewhat later stage of
development, the divisions of the limbs make their appearance, and more especially
when the quinquifid division of the digits in the hand and foot becomes percep-
tible, it is obvious that the thumb and radius in the one limb, and the great toe
and tibia in the other, occupy corresponding cephalic and preaxial situations ; and
it is not difficult to trace from these the corresponding relations of the parts in
the upper division of the limbs; and thus the radial condyle of the humerus with
the great tuberosity are preaxial, while the lesser tuberosity, ulnar condyle, ulna,
and little finger are postaxial. In the lower limb, the lesser trochanter, internal
conlyle, tibia and great toe are preaxial, while the great trochanter, external
condyle, fibula, and lesser toe, are postaxial. And at the same time the dorsal or
extensor surface of the limbs becomes external, and the ventral or flexor surface
becomes internal.

Fig. 112.—Lareran VIEW OF
THE HumMAN EMBRYO OF
ABOUT SEVEN WEEKS, SHOW-
ING THE RUDIMENTARY
LIMBS IN THEIR SECOND
Position. (A. 1.) Mac-
NIFIED 7 DIAMETERS.

7, preaxial or radial and
pollex border of the thoracic
limb ; uw, its postaxial or ulnar
and little finger border; ¢,
preaxial or tibial and hallux
border of the pelvic limb ; f,
its postaxial or fibular and
little toe border.

Very soon, however, in the higher animals and in man, farther changes operate
in bringing about the permanent form. First, there is the eversion of the humerus
so as to place the radial condyle outwards, and the inversion of the femur so as to
place the tibial condyle inwards. In the upper limb of man, the radius being in
semipronation, no material change occurs in the position of the hand, the thumb
hanging naturally forward; but in animals, destined to rest on the palmar
aspect of the hand or digits, important changes occur in the position of the
radius by which, as this bone is brought forward upon the humerus, and its
lower end carried inwards, the manus or its elements are placed permanently
in the prone position, with the first or radial digit inwards. In the
foot no such change is required, as already by the intemal rotation of the
femur at its upper part, the conditions for plantar support have been secured,
and the first or tibial digit is on the inner side. Further, in man, as the body
attains its full development, both limbs are extended in a line parallel to the
axis of the trunk, the upper dropping loosely from the shoulder-joint with the
greatest freedom of motion ; the lower more closely articulated in the hip-joint,
and suited to give firm support to the body in the erect posture.

It is proper to mention here a very ingenious view of the homologies of the
limbs which has been suggested by Martins, according to which the humerus
is to be regarded as virtually twisted upon itself to the extent of 90° at the
meck, and 90° more from that part downwards, or to the extent of 180° in
its whole length. By this torsion, Martins accounts for the deviation of the
external condyle of the humerus from the original or typical position which he
considers to remain in the femur, and thus he endeavours to show, and it must
be admitted with some appearance of probability, how, by supposing the humerus
to be untwisted, an exact correspondence of the surfaces and borders can be
established between the humerus and femur. Gegenbaur has adopted this
view, and has added some facts in illustration of it. (Ch. Martins, “ Nouv.

COMPARISON OF ARM AND LEG BONES. 127

Compar. des Membres Pelviens et Thoraciques, &c., déduite de la Torsion de
Humerus,” Mem. de l’Acad. de Montpellier, tom. iii., 1857. Gegenbaur, “ On
the Torsion of the Humerus,’ in Jenaischen Zeitsch. and Annal. des Sciences
Nat., iv., p. 50.) But it is easy to show by reference to the embryonic condi-
tion, that the outward displacement of the lower end of the humerus in the pro-
gress of its formation, does not exceed 90”.

Martins has also proposed the view, that in order to compare the lower leg
with the fore-arm, it is necessary to look upon the upper part of the tibia (corre-
sponding in the main to the radius), as including, or haying had transferred to
it as it were, the olecranon process and upper part of the ulna; and he thus
accounts for the attachment of the great extensor tendon of the leg to the tibia
through the patella, which, according to his scheme, represents the olecranon
instead of to the fibula. Ingenious as these views undoubtedly are, they are
liable to considerable objections on embryological grounds, and though not to
be rejected altogether, cannot be considered as supplying the key to the explana-
tion of the homologies of the limbs.

Hand and Foot.—The similarity of the digital and metacarpal bones of the
hand with those of the foot in number, form, and connections is so great that
the homological correspondence of these bones is immediately recognised. The
main differences between them consist in the greater general length of the digits
of the hand, and the opposability of the thumb to the other fingers through
its mobility at the carpo-metacarpal articulation,—conditions which are peculiarly
characteristic of man, and do not exist in the same form or degree in any of the
lower animals,

Fig. 118.—Dorsan Surrace or THE Ricut Manus oF Fig. 113. 5
A Warer Torrotse. (Flower after Gegenbaur.)
R, radius; U, ulna; 7, radiale ; 7, intermedium ;
wu, ulnare ; c, centrale ; 1—5, five carpal bones of the
distal row ; m!—m-*, five metacarpals.

Between the carpus and tarsus there is also
considerable general similarity, especially in the
bones of the distal series; but in those of the
proximal row there are some differences which
may be referred to here at greater length. There
can, indeed, be no doubt as to the homological
correspondence of the trapezium, trapezoid and
magnum with the internal, middle and external
cuneiform bones of the tarsus respectively, nor of
the unciform with the cuboid bone; and all the
more in the case of the last two bones, that it is
found that in the Chelonia and some other reptiles
and amphibia, the second series of carpal and
tarsal bones are increased to five by the division of the unciform of the hand
and cuboid of the foot into two each; thus giving one carpal or tarsal bone
for articulation with each of the five metacarpal or metatarsal bones.

Upon the homologies of the proximal series of bones, new light has been
thrown by the researches of Gegenbaur. (‘* Untersuch. zur Vergleich. Anat.,
&e., Carpus and Tarsus,” Leipzig, 1864.) In the simplest and most constant
form of this series in the carpus, he distinguishes typically three bones, viz.,
a radial, an intermediate, and an ulnar, corresponding respectively to the scaphoid,
tunar and cuneiform bones of human anatomy. The pisiform he regards as an
osseous element developed in the tendon of a muscle (flexor carpi ulnaris),
and therefore not holding the same rank in the series as the other bones,
but constituting an wlnar sesamoid. In the foot Gegenbaur shows that the
astragalus corresponds to the united scaphoid and lunar of the hand, or to
the proximal parts at least of these bones. But in some mammals (Simiae and
Rodentia), as well as in reptiles and amphibia, another bone has long been known

198 MORPHOLOGY OF THE BONES OF THE LIMBS.

to exist, interposed between the bones of the proximal and distal rows, and more
immediately between the scaphoid and lunar and the trapezium and trapezoid.
This bone is termed the os centrale, and several circumstances appear to indicate
that it most frequently corresponds to a part of one of the proximal bones. In
the carnivora and some.other mammals, the scaphoid and lunar are united in
the adult into one bone, the scapho-lunar, and Flower has observed, that in the
young dog there is frequently, but not invariably, a separate ossification in the
distal part of the scapho-lunar corresponding in position and relations with the
os centrale of other animals (Flower, Journ. of Anat., vol. iv., 1870); anda similar

Fig. 114.—Dorsan Surracz or tHe Riant Carpus or Man (Flower). 4}

s, scaphoid ; J, lunar ; ¢, cuneiform ; p, pisiform; ¢m, trapezium ; td, trapezoid ;
m, magnum ; uv, unciform ; I—V, five metacarpals.

Fig. 115.—Dorsat Surracz or tHE Carpus or A Bapoon (Flower).
s, scaphoid ; 7, lunar; c, cuneiform ; p, pisiform ; tm, trapezium ; td, trapezoid ;
m, magnum ; uv, unciform ; 7s, radial sesamoid ; ce, os centrale; I—Y, five meta-
carpals.

observation has been made in the carpus of the young lion by Wilder (1873),
But in both of these animals in the adult this piece of bone has become com-
pletely ossified, so as to form one with the scapho-lunar. It seems probable that
in some animals a central bone may be derived from the separation of the
proximal part of the os magnum.

The determination of the homology of the navicular bone of the tarsus is not
yet fully made out, but it seems most probable that this bone corresponds not to
any single or entire bone of the carpus, but rather to the os centrale, together
with a detached portion of the scaphoid.

In some animals there is a tenth separate bone of the carpus. which seems
most nearly to correspond to the tuberosity of the scaphoid : this constitutes the
typical radial sesamoid of Gegenbaur, and the navicular bone of the tarsus may per-
haps correspond to this along with the oscentrale. It is interesting to remark that
this bone is sometimes found separate in the human hand. (See W. Griiber,
Struthers, Turner, and others, in Journ. of Anat., and Mivart “On the Ap-
pendicular Skeleton of the Primates” in Philos. Trans. 1867.)

The os calcis is generally believed to correspond most nearly with the cuneiform
of the carpus, and by some it has been held to include the pisiform,—a view not
participated in by Gegenbaur, but of the truth of which any one will be
convinced by the inspection of the hand and foot of the bear. It is deserving of
remark that in the young of that animal, the much enlarged pisiform possesses
an epiphysis of its own, exactly similar to the one known as existing on the
tuberosity of the calcaneum,—a fact observable also in other animals, and which
of itself refutes the view taken by some that the pisiform corresponds to the
epiphysis of the calcaneal tuberosity. (Allen Thomson.)

The following tables present a synoptical view of the corresponding or homo-
logous bones or other parts in the thoracic and pelvic limbs.

MORPHOLOGY OF THE BONES OF THE LIMBS. 129

I.—TABLE OF THE HomoLoGcous BONES IN THE THORACIC AND PELVIC LIMBS

THORACIC LIMB.

Scapula
Precoracoid
Coracoid
Glenoid cavity
Clavicle
Humerus .
Great tuberosity
Small tuberosity
External condyle .

Radius

Ulna

Carpus

Metacarpus . z
Pollex ; .

Digital phalanges .

PELVIC Limes.
Tlium.
Pubis.
Ischium.
Cotyloid cavity.
Absent.
Femur.
Lesser trochanter.
Great trochanter.
: Internal condyle.
5 Ulbiaytry
Fibula.
Tarsus.
Metatarsus.
Hallux.
Digital phalanges.

= 10k —TABLE OF THE HOMOLOGOUS BONES OF THE CARPWS AND TARSUS

a nT.
CARPUS.
Typical Names. Names in Human Anatomy.
Radiale Scaphoid at
: . Astragalus
Intermedium Lunar ai BT
Ulnare Cuneiform a] Og calcik
as cis
Ulnare sesamoideum. Pisiform . en | é

Centrale % ae

Radiale sesamoideum

Chod Chy REHGEGENBAUR).

(part of scaphd, or
other bone) . » Navicular
(part of scaphoid)

i Fibulare
* ( Fibulare sesa-

TARSUS.

Typical Names.
§ Tibiale.

. ) Intermedium.

moideum

§ (Centrale)

* (Tibiale sesamoi-

deum)

Carpale I. Trapezium Int.Cuneiform Tarsale I.
Trapezoid . Mid. Cuneif. . — ils
—— Ill Magnum : . Ext. Cuneif. —— I.
gancal -) Unciform . . Cuboid Bar ce Uae
——v. . 5) aaah (—— Vv

TII.—TABLE OF THE HOMOLOGOUS PARTS OF THE SCAPULA AND ILIUM

(ACCORDING TO FLOWER).

SCAPULA.
Supraspinous fossa
Infraspinous fossa .
Subscapular fossa
Base
Spine and acromion
Superior angle
Inferior angle
Superior border

External or glenoid border .

TLIUM.

Sacral and true pelvic surface.
Iliac fossa.

Gluteal or dorsal surface.

Iliac crest. “
Tlio-pectineal line and eminence.
Posterior superior spine.

Anterior superior spine.
Posterior or ischial border.
Anterior or cotyloid border.

ADAPTATION OF THE SKELETON TO THE ERECT ATTITUDE.

The axial skeleton of man is, for the purposes of station and progression
raised more fully to the vertical position than is the case in any animal; and
along with this the lower limbs are extended in lines parallel to the axis of the
trunk. The feet rest on the ground by the contact of the heel and the balls of
the toes, the centre of gravity of the body falling within the basis of support.
For the maintenance of this attitude, the constant “action of the muscles passing

VOL. I.

K

130 ERECT ATTITUDE OF THE SKELETON.

over the ankle-joint is more immediately necessary. But at the knee and hip-
joint, it is mainly by the mechanism of the ligaments and other parts of the
joints, and less directly by muscular action, that the erect attitude is maintained,
as will be more fully shown in the description of the different articulations.

There are, besides, many peculiarities in the construction of the body, and
especially of the skeleton, which are associated with the assumption of the erect
posture, and although many of them have been noticed in the description of the
several sets of bones, it may still be useful to recapitulate them briefly in this place.

It may first be remarked that the full development of these peculiarities
belongs to the adult condition. In the infant, while still unable to walk, the
large proportional size of the head, amounting to nearly a fifth of the whole
body, the comparative straightness of the vertebral column, or absence of the
curves which characterise the spine of the adult, the shortness of the lower limbs,
and incompleteness of their structures, all contribute to render the assumption
of the erect attitude by the child, for a time, difficult and insecure. Thus the
middie distance between the vertex of the head and the foot in a child is
situated somewhat above the umbilicus, while in the adult it is generally at the
upper border of the pubis, or even lower in some part of the symphysis. In the
child also, from the large dimensions of the head and upper part of the body, the
centre of gravity is carried to a considerably higher point than in the adult.

The skull of man differs from that of animals in being nearly balanced on the
vertebral column, the condyles of the occipital bone being brought forward to
near the middle of the base, by the comparative shortness of that part of the
skull which lies in front of the foramen magnum, and the projection backwards
of that which lies behind it. In animals the skull hangs forwards, as it were,
from the extremity of the column, and is sustained by the elastic ligamentum
nuche, represented in man by a comparatively feeble structure which passes
between the external occipital protuberance, and the spinous processes of the
cervical vertebre.

The spinal column, by its pyramidal form, is fitted to sustain the weight which
bears down upon its lower part, and by means of its different curvatures possesses
elasticity and strength combined, and allows considerable range of motion to the
trunk, without removal of the centre of gravity from within its base. The
strong and expanded sacrum is the immediate means of transferring the weight
of the trunk to the ossa innominata and lower limbs.

The pelvis is of peculiar breadth in man, presenting an upper and lower arch
which meet at the hip-joints, and is so inclined that a vertical line descending
from the centre of gravity of the body is in a plane slightly behind the centres
of motion of the hip-joints. The breadth of the pelvis enables the balance to be
more easily maintained in lateral movements of the body by compensating
inclinations of different parts to opposite sides of the basis of support, and the
long neck of the femur gives an advantageous insertion to the muscles by which
the balance of the body is principally preserved. The os innominatum is mainly
distinguished from the same bone in animals by the breadth of its iliac portion,
which gives support to the abdominal viscera, and attachment to the greatly
developed iliac and gluteal muscles.

The lower limbs are remarkable for their length and strength. The femur is
greatly elongated, its length considerably exceeding that of the tibia,—a condi-
tion which is requisite not only to give a sufficient extent of stride, but also to
enable the body to be balanced in different degrees and varieties of stooping.
The foot of man alone among animals has an arched instep, and it likewise
presents a great breadth of sole. The great toe is distinguished by its full
development, and especially from that of the quadrumana, by its want of
opposability, being constructed, not for grasping, but for supporting the weight
of the body, and giving spring to the step.

While stability and strength are thus provided in the lower limbs, mobility and
lightness are secured in the upper. This is apparent on comparison of the
shoulder, elbow, and wrist, with the hip, knee, and ankle. In the hand, also,
the moyable phalanges are as long as the carpal and metacarpal bones taken

together, while in the foot they are not a third of the length of the tarsal and
metatarsal bones,

ARTHROLOGY.—DIFFERENT KINDS OF JOINTS. 131

Section I].—-ARTHROLOGY.

THE ARTICULATIONS IN GENERAL.

Various Forms or Jornts.—The name of articulation, synonymous
with joint, is given in descriptive anatomy to the connection subsisting
in the recent skeleton between any of its denser component parts,
whether bones or cartilages. In most instances some softer intervening
substance lies between the bones, uniting them together, or clothing the
surfaces which are opposed; but the manner in which the several
pieces of the skeleton are thus connected, varies to a great degree both
as to the nature of the uniting substances, and the extent of movement
which they allow. In some instances, as in the cranial bones, the
closeness of the apposition, the unevenness of the fitting surfaces or
edges, and the small amount and dense nature of the intervening sub-
stance (periosteum), admit of little or no perceptible movement. In
other instances of continuous union the extremities of the bones are
placed at such a distance, and the intervening substance (ligament or
cartilage) is so yielding, that bending or other movements- may take
place. But in the greater number of articulations the apposed surfaces
of bone are not united either directly or mediately with each other, but
are free, and covered with plates of smooth cartilage, the surfaces of
which fit accurately together, while the bones are held together by
ligamentous structures placed in the vicinity of the joints. In such
articulations the bones are capable of gliding or moving upon each
other, the extent and directions of such movements varying with the
shape of the opposed cartilaginous surfaces, and the form and attach-
ments of the ligamentous and other bands which unite them. It is
upon distinctions such as those now adverted to that the various kinds
of joints or articulations have been brought under the three classes of
Synarthrosis, Amphiarthrosis, and Diarthrosis.

Synarthrosis means direct or immediate union, and comprehends
the joints with little or no motion. It is found chiefly in the various
forms of suture by which the bones of the head, excepting the lower
jaw, are united. The suture is serrated or dentated when the contiguous
margins of the bones are subdivided or broken up into projecting points
and recesses by which they fit very closely to one another, as in the
borders of most of the tabular bones of the cranium. The squamous or
scaly suture is that in which, as in the union of the temporal with the
parietal bone, the edges are thinned and bevelled, so that one overlaps
the other to a considerable extent.

The harmonic suture or harmonia is the term employed to denote
simple apposition of comparatively smooth surfaces or edges, as in the
case of the two superior maxillary bones; and the term schindylesis is
applied to that kind of union in which one bone is received into a
groove in another, as occurs between the rostrum of the sphenoid bone
and the vomer. The impaction of the roots of the teeth in their sockets
has likewise been reckoned among the articulations, though with
doubtful propriety, and has been designated by the term yomphosis.

K 2

132 THE JOINTS IN GENERAL.

Amphiarthrosis means the mixed articulation, or that in which
there is mediate union by some intervening substance, with partial
mobility. The articulations between the bodies of the vertebra, that
between the two ossa pubis at the symphysis, and that between the two
first pieces of the sternum, may be taken as examples of this mode of
connection. Some of the joints of this kind pass on the one hand into
synarthrosis, and on the other into diarthrosis.

Diarthrosis includes the complete joints, with synovial cavities sepa-
rating the surfaces of the articular bones, and is attended with consider-
able yet varying degrees of mobility. In this form of joint, plates of carti-
lage cover the articular parts of the bones and present within the joint
free surfaces of remarkable smoothness, and these surfaces are further
lubricated by the synovial fluid secreted from the delicate membrane
which lines the fibrous coverings and all other parts of the articulating
cavity except the cartilage. This membrane is continuous with the
margin of the articular cartilages, and along with them completely
encloses the joint cavity. The bones are further held together by
fibrous tissue in the various forms of ligaments, such as membranous
capsules, flat bands, or rounded cords. These ligaments, it is true, are
not so tight as to maintain the bones in close contact in all positions of
the joint, but are rather tightened in some positions and relaxed in
others, so that they may be looked upon chiefly as controllers of move-
ments. The bones are likewise held together in diarthrodial joints, by
atmospheric pressure, and by the surrounding muscles. Certain forms
of diarthrodial joint have received special names. The term ginglymus
is used to distinguish a hinge joint, or one which admits only of flexion —
and extension, like the elbow, knee and ankle. Znarthrosis (Cruveil-
hier) is the_ball-and-socket form of joint, like the shoulder and hip,
allowing motion in every direction. Arthrodia is a joint with nearly
flat surfaces, which admits of gliding movement merely, as in the arti-
culations of the carpus, tarsus, and articular processes of the vertebrae.

Various Kryps or Movement.—The various movements of the
bones in diarthrodial joints are distinguished by different terms ac-
cording to their directions, viz., angular movement, circumduction,
rotation, and gliding ; but itis proper to remark that although different
kinds of movement, answering to these several terms, may readily be
recognised, yet they are rarely of only one kind in any joint, but rather
several kinds of movement are frequently combined, and they also run
into one another in great variety.

Angular movement is movement in such a manner as to increase
or diminish the angle between two bones, so that they shall lie more or
less nearly in a straight line. The different kinds of angular movement
are designated by different terms according to the directions in which
they take place with reference to the limb or body: thus flewion and
extension indicate angular movements, which have the effect of bending
or straightening parts upon one another or upon the trunk of the body:
adduction and abduction indicate angular movement to and from the
mesial plane of the body, or, when fingers and toes are referred to, these
terms may be used to denote movement to and from the middle line of
the hand or foot.

Coaptation is a form of angular movement, in which, as in the movement of
the patella on the femur the articular surface of one bone travels over that of
another, so as to bring different parts of the surfaces successively into contact in

THE VERTEBRAL ARTICULATIONS. 133

the manner of a wheel rolling on the ground, this movement being usually
accompanied by a certain amount of gliding.

Circumduction is the movement performed when the shaft of a
long bone or a part of a limb describes a cone, the apex of which is
placed in the joint at or near one extremity of the bone, while the sides
and base of the cone are described by the rest of the moving part.

Rotation signifies movement of a bone round its axis without any
great change of situation.

Gliding is applied to that kind of movement in which the surfaces
of adjacent bones are displaced without any accompanying angular
or rotatory motion, as in the movement of flat surfaces over each other
in some of the carpal and tarsal articulations, or in the movement of
advance and retreat of the lower jaw.

In the various joints provided with synovial cavities, the cartilaginous surfaces
of the bones are so formed as usually to be in close apposition or contact ; but in
certain positions they are not entirely so, and there are even instances in which
the separation of the surfaces must be considerable, as in the case of the patella,
in some positions of the knee. In these cases the vacuity is filled up by folds
of the synovial membrane, or by fatty processes connected with it.

ARTICULATIONS OF THE TRUNK AND HEAD.
ARTICULATIONS OF THE VERTEBRAL COLUMN.

The moveable vertebrae are connected together by elastic discs inter-
posed between the bodies ; by synovial joints between the articulating
processes ; and by ligaments.

The intervertebral discs are plates of composite structure placed
between the bodies of the vertebrae from the axis to the sacrum. Each
is composed of a fibro-laminar part externally, and of a pulpy substance
in the centre.

Fig, 116.—A Lumpar VERTEBRA, SEEN FROM Fi
ABOVE, WITH PART OF THE INTERVERTEBRAL
Disc ADHERING TO THE Bopy. 4

1, 1, the concentric arrangement of the fibrous
lamine ; 2, the central soft cartilaginous or
gelatinous substance.

The laminar part forms more than
half of the mass, and consists of con-
centric lamin of fibro-cartilage and
fibrous tissue alternating one with
another. These laming are not quite
vertical, for if a vertical section of a
disc be made, a certain number of the
layers nearest to the circumference of
the disc will be seen bulging outwards,
while others situated more deeply and less closely compacted together
are convex towards the centre; and when the spine is bent in any
direction, the curves of the different layers are augmented on the side
towards which the column is inclined. The individual layers consist
chiefly of fibres extending obliquely between the vertebree and firmly

134 ARTICULATIONS OF THE TRUNK.

attached to both; the direction of the fibres being reversed in each
successive layer. Some of the fibres also are nearly horizontal. The
central part of the fibro-cartilage is a pulpy and elastic material which,
when the pressure which confines it is taken off by cutting through
the intervertebral substance, rises up so as to assume a conical form.
Tt is then seen to be of a lobate structure, and, examined under the
microscope, exhibits a finely fibrous and homogeneous matrix, with
numerous spherical and elliptical cells, some of them resembling carti-
lage-corpuscles, others larger and of various appearance.

It is now generally admitted that the pulp of the intervertebral disc is a per-
sistent part of the chorda dorsalis; homologous, therefore, with those larger
vestiges of the chorda dorsalis which occupy the biconical cavities between the
bodies of the vertebrie in fishes. According to Luschka, there is present in each
disc a synovial cavity, and the lobes of the pulp are synoyial villi, similar to
those which are to be found in the knee and shoulder joints, but of larger size,
and occupying the whole cavity ; and it is worthy of notice that in like manner
secondary cavities, developed within the chorda dorsalis, are found in the inter-
vertebral substance in many fishes. (Luschka, ‘t Die Halbgelenke des Menschli-
chen Kérpers,” Berlin, 1858, p. 84.)

A thin cartilaginous layer, incomplete towards the circumference,
covers the surfaces of the vertebrae and gives attachment to the discs.
Excluding from consideration the first two vertebra, between which it

Fig. 117. Fig. 117.—Vertican AnrEro-
PostrRtoR SECTION THROUGH
two LumBar VERTEBRH, SHOW-
ING THE ARRANGEMENT OF THE
INTERVERTEBRAL Disc. 3
1, 1, the fibrous oblique bands,

which are curved outward ; 2,

those which are curved inwards ;

3, the central soft cartilaginous or

gelatinous substance : the capsule

of the joint between the articular
processes 1s represented.

does not exist, the inter-
vertebral material forms in
length about a fourth of
the movable part of the column. The dorsal part of the column has,
in comparison with its length, a much smaller proportion than the
cervical or lumbar parts.

The discs in the cervical and lumbar regions are thicker in front than behind,
and it has been determined that the convexity of those portions of the column is
due to them much more than to the bodies of the vertebrae, while the arching of
the dorsal portion, on the contrary, is rather owing to the shape of the bones.
(W. and E. Weber, “‘ Mechanik der menschl. Gewerkzeuge,” p. 90, et seq., GOt-
tingen, 1836.)

The anterior common ligament is a strong band of fibres, which
is placed on the front of the bodies of the vertebrae, and reaches from
the axis to the first bone of the sacrum, becoming broader as it descends.
It consists of longitudinal fibres which are dense, firm, and well marked.
The superficial fibres extend from a given vertebra to the fourth or fifth
below it; the fibres beneath these pass over the bodies of several verte-

COMMON VERTEBRAL LIGAMENTS. 135

bree; whilst the deeper ones pass only between adjacent vertebre. The
band is thicker towards the middle of the bodies of the vertebree than
at their margins, or over the intervertebral cartilages ; by which means
the transverse depressions of the bodies are filled up, and the surface of
the column rendered more even. ‘The fibres adhere more closely to the
margins of the bones than to the middle of their bodies, and still more

Fig 118.—Tue 5ra, 67H, 7TH, STH Fig. 118.
AND 9TH DorsAL VERTEBRS, WITH
A PART OF THE 6TH, 7TH, AND STH
Rips, FROM THE RIGHT SIDE AND
Front, ((A0 I) 3

1 to 2, the anterior common liga-
ment of the bodies of the vertebrae ; at
+ +, a portion of the ligament is
removed so as to expose the inter-
vertebral plate between the 8th and
9th vertebree, in which the diagonal
fibres of the external laminze of the
intervertebral disc are represented.
(The further description of this figure
will be found at p. 141.)

»

closely to the invertebral car-
tilages. Upon the sides of the
bodies there are some fibres
which are thin and scattered,
and reach from one bone to
another.

The posterior common
ligament is situated within
the spinal canal, and is at-
tached to the posterior surface
of the bodies of the vertebree ;
it extends from the axis to the
sacrum. At its upper extremity f
it is continuous with the apparatus ligamentosus. It is smooth,
shining, and broader at the upper than at the lower part of the spine.

Cdn MAY |
SU iyi \

Fig. 119.—Tue Bopres or torre Lumpar VERTEBRE, SEEN FROM Fig. 119.
BEHIND, WITH THE PostERIOR Common LicaMENT. §

The arches have been removed by cutting through the pedicles.
The narrowing of the posterior common ligament opposite the
middle of each body, and its greater width and attachments opposite
the intervertebral discs, are represented.

In the neck it extends quite across the bodies of
the vertebree, but in the back and loins it is broader
opposite the intervertebral cartilages than at the
middle of the bodies, so that its margins present a
series of points or dentations with intervening concave
spaces. it adheres firmly to the fibro-cartilages and
to the contiguous margins of the bodies of the vertebra, but it is
separated from the middle of the bodies by the transverse parts of the
large venous plexus. Between the ligament and the prolongation of the
dura mater which lines the canal, some loose connective tissue 1s
interposed. .

136 ARTICULATIONS OF THE TRUNK.

The joints of the articulating processes present each a synovial
cavity surrounded by an irregular fibrous capsule. he fibrous bands

Fig. 120.—Taum Arcurs or THREE Dorsat VER-

TEBRE, SEEN FROM BEFORE. }

The bodies of the vertebrae have been removed by

sawing through the pedicles, to show the articular
capsules and the ligamenta subflava.

of these capsules are longer and looser in
the cervical than in the dorsal and Jumbar
regions.

The ligamenta subflava are ligaments
consisting of yellow elastic tissue, which
connect the lamine of the vertebra. Their
fibres are nearly vertical, and are attached
superiorly to the anterior surface of the
lamina of one vertebra near its inferior margin, and inferiorly to the
upper margin and part of the posterior surface of the lamina of the

Fig. 121.—Anrero-Postertor VerticaL SEc-
TION OF THE UPPER PART OF THE VERTEBRAL
CoLUMN, AND PART oF THE OccrrITaL Bone,
SHOWING THE ArticuLAtions. (A. T. after
Arnold. )

1, 1, anterior common ligament of the bodies
of the vertebre ; 1’, anterior atlanto-occipital
ligament ; 2, from this figure upwards the pos-
terior common ligament of the bodies ; 2’, the
continuation of the preceding or apparatus liga-
mentosus lying on the basilar process of the
occipital bone ; 3, 3, 3, these figures are placed
on the inside of the arches of the 2nd cervical
and 1st and 6th dorsal vertebre ; the ligamenta
subflava are to be seen stretching between the
Jaminee ; 4, 4, placed upon two of the inter-
spinous ligaments; 4’ divided edge of the
occipital bone behind the foramen magnum, and
below it, the posterior occipito-atlantal ligament ;
5, 5, supraspinous ligaments; 6, ligamentum
nuche ; +, its upper extremity at the occipital
tuberosity ; ++, its lower extremity terminat-
ing in the supraspinous ligaments of the upper
dorsal vertebrie.

vertebra beneath. They are most dis-
tinctly seen when the arches are de-
tached from the bodies of the vertebrae,
and they are viewed from the front.
Posteriorly they appear short, and in
the dorsal region are concealed by the
prominent inferior margins of the
lamine and the roots of the spines.
Their outer margins are close to the
articulating processes ; their inner margins are thickened and in contact
with each other beneath the root of the spinous process.

The ligamenta subflava do not exist between the occiput and the

VERTEBRAL LIGAMENTS. 137

atlas, nor between the latter and the axis ; common fibrous membrane
supplies their place in these two spaces, constituting posterior occipito-
atlantal and atlanto-axial ligaments.

The interspinous ligaments, thin and rather membranous, have an
attachment extending from the root to near the summit of each spinous
process, and connect the inferior border of one with the superior border
of that next below it. They are best seen in the lumbar region, and are
least developed in the neck.

The supraspincus ligaments consist of small compressed bundles
of longitudinal fibres, which connect the summits of the spinous pro-
cesses, and form a continuous chain from the seventh cervical vertebra
to the spine of the sacrum. The superficial fibres pass down from a
given vertebra to the third or fourth below it; those more deeply
seated reach only from one to the next, or the second below it.

The ligamentum nuche is the continuation upwards of the
supraspinous ligament. It is, in the human subject, a thin inter-
muscular septum of elastic and white fibrous tissue, the most super-
ficial part of which extends from the spine of the seventh cervical
vertebra to the occipital protuberance, while the deeper fibres, springing
from the same origin, pass to the occipital spine, and the spines of the
six upper vertebree. It is the representative of a strong elastic struc-
ture which suspends the head in the lower animals.

The intertransverse ligaments are unimportant bands extending
between the transverse processes. In the lumbar regions they are
membranous, in the dorsal region they are rounded bundles intimately
connected with the muscles of the back; and in the neck they are
usually reduced to a few irregular fibres, which may in some instances
be wanting.

Movements.—The movements of flexion and extension of the vertebral column
are freely allowed in the cervical and lumbar regions, but in the dorsal are limited
by the small amount of intervertebral substance and the imbrication of the
lamine. The greatest bending backwards is permitted in the cervical, the
greatest bending forwards in the lumbar region, especially between the fourth
and fifth lumbar vertebrae. Movements in other directions are limited chiefly by
the articular processes. In the dorsal region the articular surfaces of each verte-
bra lie in the are of a circle whose centre is in front of the vertebra, and round
this centre a considerable degree of rotation is permitted. Im the lumbar
region, the centre of the circle in which the articular surfaces lie is placed. behind,
so that rotation is prevented; the articular processes, however, fit sufficiently
loosely to permit of lateral flexion, and by combination of this with antero-pos-
terior flexion, some degree of circumduction is produced. The articular sur-
faces of the cervical vertebra, being oblique and placed in nearly the same trans-
verse plane, allow neither pure rotation nor pure lateral flexion. They permit,
besides forward and backward motion, only one other, which is rotatory round
an oblique axis—the inferior articulating process of one side gliding upwards
and forwards on the opposing surface, and that of the other side gliding down-
wards and backwards, by which a combination of lateral flexion and rotation 1s
obtained.

ARTICULATIONS OF THE ATLAS, AXIS, AND OCCIPITAL BONE.

The atlas, axis, and occipital bone are connected by articular surfaces
and ligaments, without the presence of intervertebral discs.

Two pairs of synovial articulations, surrounded by capsular
ligaments, connect the lateral masses of the atlas with the superior

cr

138 ARTICULATIONS OF THE TRUNK AND HEAD.

articular surfaces of the axis and with the condyles of the occipital bone.
The atlanto-axial capsule is strengthened behind by an accessory liga-
ment, directed downwards and inwards to the body of the axis near the
base of the odontoid process.

The transverse ligament of the atlas is a strong and thick
band, which extends across the ring of the atlas, and retains the odon-
toid process in its place. It is attached on each side to the tubercle
below the inner border of the superior articulating process. It is arched
backwards behind the odontoid process, and is broadened out in the
middle line. From the middle of its posterior surface a short thin
bundle of fibres passes down to be attached to the body of the axis,
whilst another passes up to the basilar process. These form, with the
transverse portion, the figure of a cross, and serve to bind the occiput
to the first two vertebree ; from this arrangement is derived the term
cruciform, which is sometimes applied to the transverse ligament and
its appendages together.

Fig. 122. Fig. 122..—TransversE VER-
TICAL SECTION OF THE

1 LOWER PART OF THE Oc-
z crpITAL Bong, AND THE
TWO UPPER VERTEBRE
BEHIND THE ARTICULA-
mrons (A. T. after Arnold).
al

2

\
ANY
i
We

Vis i
4 Di |

= a
Mf GN

wit

1, 1, apparatus ligamen-
tosus turned up on the occi-
pital bone; 2, 2’, vertical
part, and 3, 3, transverse
or principal part of the cru-
ciform ligament; x, neck
of the odontoid process ; 4,
4, the alar or lateral odon-
toid ligaments; 5, 5, the
accessory ligaments of the
atlanto-axial capsules ; 6, 6, part of the capsular ligaments of the condylar articulations ;
7, 7, capsular ligaments of the atlanto-axial articulations ; 8, 8, intertransverse ligaments
between the occiput and atlas.

Two synovial membranes are placed one in front and another
behind the odontoid process ; the first of these is situated between the

Fig. 123. Fig. 123.—Horizontan SrctioN THROUGH THE
Oponto-ArLaAnraL Anrricunation. (A. T.) §

1, eut surface of the odontoid process; 2,
cut surface of ‘the anterior arch of the atlas ;
3, transverse ligament; between 1 and 2, the
anterior synovial cavity, and between 1 and 3, the
posterior synovial cavity of the articulation ; 4, is
placed on the back part of the left superior arti-
cular process of the atlas; the anterior part of
this process, and that of the other side, have been
partly removed by the section. For the sake of
distinctness, the synovial spaces are represented
somewhat wider than natural.

process and the anterior arch of the atlas, the other between the process
and the transverse ligament.

OCCIPITO-VERTEBRAL ARTICULATIONS. 139

The lateral or alar odontoid ligaments are two thick and very
strong bundles of fibres, which extend from the sides of the summit of the
odontoid process outwards and a little upwards to be implanted into the
rough depression on the inner side of
each condyle of the occipital bone, and
into a small part of the margin of the
foramen magnum. Some of the fibres
of the two ligaments are continuous across
the middle line.

Fig. 124.—TransversE SECTION SIMILAR TO
THAT REPRESENTED IN Fic. 122, THE Cruct-
FORM LIGAMENTS HAVING BEEN REMOVED. (A.
me)

4, alar odontoid ligament ; 5, accessory atlanto-
axial ligament; 6, 7, capsular ligaments of the
occipito-atlantal and the atlanto-axial articulations ;
9, head of the odontoid process ; 9, 9’, middle
odontoid ligament.

Fig. 125.—Tur Licameytovs Srrucrurnes wich surRouND THE ARTICULATIONS oF
THE Occrpur anp two Upper VerRTEBRE. }

A, the lower part of the skull sawn transversely through the basilar process, with the
atlas and axis, viewed from before. 1, the anterior occipito-atlantal ligament; 2, the
accessory occipito-atlantal ligament ; 3, the anterior atlanto-axial ligament.

I, the lower part of the skull, with three adjacent vertebrae, viewed from behind. 1,
the posterior occipito-atlantal ligament ; 2, the posterior atlanto-axial ligament.

C, the occipital bone sawn transversely through the foramen magnum, and a part of the
arches of the atlas and axis removed posteriorly, so as to show the apparatus ligamentosus.

140 ARTICULATIONS OF THE TRUNK AND HEAD.

The ligamentum suspensorium dentis or middle odontoid ligament
consists of fibres which pass directly upwards from. the summit of the
odontoid process to the margin of the foramen magnum.

The occipito-axial ligament sometimes called apparatus ligaimen-
tosus colli, is the continuation upwards of the posterior common liga-
ment, and by its breadth covers the cruciform and odontoid ligaments.
It is attached above in the basilar groove, and below to the body of
the axis.

The anterior occipitco-atlantal ligament extends from the ante-
rior border of the occipital foramen, between the condyles, to the anterior
arch of the atlas. It is thin, broad, and membranous; but in the
median line it is strengthened by an accessory ligament, thick and
round, placed in front of it, which is sometimes described as the com-
mencement of the anterior common ligament.

The anterior atlanto-axial ligament, likewise thin and mem-
branous, except in the middle, where it is considerably thickened,
extends from the anterior arch of the atlas to the body of the axis.

The posterior occipite-atlantal ligament, thin and membranous,
is attached superiorly to all that part of the margin of the occipital
foramen which is behind the condyles, and inferiorly to the adjacent
border of the arch of the atlas. It is partly blended with the dura
mater.

The posterior atlanto-axial ligament, similar to the preceding,
connects the neural arch of the atlas with that of the axis, in the
absence of ligamentum subflavum,

Movements.—The atlanto-axial articulation is so constructed that the head,
together with the atlas, is rotated on the axis; the odontoid process serving as a
pivot. The rotation is limited by the check ligaments. The occipito-atlantal
articulation takes no part in rotation, but allows the head to be freely raised or
depressed upon the vertebral column. When the atlas is placed symmetrically
over the axis, it is seen that the opposing articular surfaces, instead of fitting
one to the other, come very slightly into contact, the surface of the axis being
inclined too little outwards, and presenting an antero-posterior convexity, to
which there is no corresponding concavity presented by the atlas; but a slight
rotation brings the bones into a stable position, in which the anterior half of
one articular surface of the axis and the posterior half of the other, are laid
closely against the atlas. It will also be found that a small amount of oblique
motion between the atlas and occipital bone is permitted, by which the anterior
half of one condyle and the posterior part of the other may be rested together on
the atlas, and that that is the position of greatest stability. This oblique posi-
tion is that into which the bones are brought when there is any lateral flexure
of the column, as is the case in the most natural and easy attitudes.

ARTICULATIONS OF THE RIBS.

The articulations of the ribs may be divided into three sets, costo-
central, costo-transverse, and costo-sternal.

The COSTO-CENTRAL ARTICULATION unites the head of the rib, in most
instances, with the bodies of two vertebre by two distinct synovial
joints, supported by ligaments as follows.

The anterior costo-central ligament, radiated or stellate, consists
of three bundles, of which the middle one passes horizontally forwards
upon the corresponding intervertebral fibro-cartilage, the superior
ascends to the body of the vertebra above it, and the inferior descends

THE COSTO-SPINAL ARTICULATIONS. 141

to that below. In the first, eleventh, and twelfth ribs, this ligament
is inserted into only one vertebral body, and into no fibro-cartilage.

Fig. 126.—Tue 51H, 6ru, 71H, 87H, Fig. 126.
AND 97TH DorsaL VERTEBRE, WITIL
PARTS OF THE 6TH, 7TH AND STI
Rips, FROM THE RIGHT SIDE AND
Front. (A. 7.) 3

The 9th rib has been removed to
show the articular surfaces of the ver-
tebree corresponding to it; 3 & 4, the
heads of the 6th and 7th ribs, from
which the stellate ligaments are seen
spreading over the two adjacent verte-
bral bodies and intervertebral substance;
5, the head of the 8th rib, from which
the stellate ligament has been removed,
so as to expose the upper and lower
synovial cavities, and between them
the interarticular ligament ; 6, lower,
and 6’, upper facet of the costo-central
articulation ; 7, posterior costo-trans-
verse ligament ; 7’, the costo-transverse
synovial cavity ; 7”, the costo-transverse
articular facet ; 8, superior costo-trans-
verse ligament ; 9, superior articular
process of the 5th vertebra ; 9’, inferior
of the 9th.

The interarticular liga-
ment is a thin and short band
of fibres, which passes trans-
versely from the ridge separating the two articular surfaces on the
head of the rib to the intervertebral substance, and divides the articu-

Fig. 127.—Five Dorsat VERTEBRE, WITH PORTIONS Fi
OF THE CORRESPONDING Rips. +

1 and 2 are placed on the laminz of the vertebree.
close to the interspinous ligaments ; 3, ligamentum sub-
flavum ; 4, anterior costo-transyerse ligament ; 5, poste-
rior costo-transverse ligament.

lation into two parts, each lined by a separate
synovial membrane. The lgament does not
exist in the articulations of the first, eleventh,
or twelfth ribs, as these ribs are each attached
to only one vertebral body by a single syno-
vial joint.

The COSTO-TRANSVERSE ARTICULATION
unites the tubercle and neck of the rib to the corresponding transverse
process by a synovial joint and ligaments, and by a longer ligament
to the transverse process of the vertebra above.

The posterior costo-transverse ligament is a distinct band
extending outwards from the posterior part of the summit of the trans-
verse process to the rough external part of the tubercle of the rib.

The middle or interosseous costo-transverse ligament, consists
of a series of short parallel fibres, which unite the neck of the rib
to the anterior surface of the contiguous transverse process. These

142 ARTICULATIONS OF THE TRUNK.

fibres are seen on removing hy horizontal section a portion of the rib
and transverse process, and forcibly drawing the one from the other.

Fig. 128.—Horizontan Srcrion
oF A DorsAL VERTEBRA, WITH
THE ADJACENT PORTIONS OF TWO
Riss. 3
1, the rib; 2, transverse pro-

cess 3 3, anterior costo-central liga-

ment ; 5, posterior costo-transverse
ligament ; 6, interosseous or middle
costo-trausverse ligament.

The superior costo-
transverse ligament, “-
terior or long, consists of
fasciculi of fibres, passing
from the neck of the rib
obliquely upwards and outwards to the lower margin of the transverse
process next above it. It does not exist in the articulation of the first
rib.

There are no synovial joints, but. only posterior costo-transverse
ligaments, between the two lowest ribs and the transverse processes.

The COSTO-STERNAL ARTICULATIONS, situated between the anterior
extremities of the cartilages of the sternal ribs, and the corresponding
fossee in the margins of the sternum, consist of small synovial capsules
covered and supported by anterior, posterior, upper and_lower ligaments.
The anterior ligamentous fibres are thin, scattered, and radiated, passing
from the extremity of the cartilage to the anterior surface of the
sternum, where they interlace with those of the opposite side, and are
blended with the aponeurosis of the pectoralis major muscle; the
posterior fibres are similarly disposed, but not so thick or numerous,
and connect the thoracic surfaces of the same parts; the upper and
lower ligamentous fibres are inconsiderable, and are placed above and
below the joint. Synovial cavities are interposed between the end of
the cartilage of each true rib (excepting the first) and the sternum, that
of the seventh is single ; the others are usually divided into an upper
and lower cavity by interarticular fibres attached to the end of the
cartilage and to the sternum. ‘The cartilage of the first rib is almost
always directly united to the sternum.

A thin fasciculus of fibres connecting the cartilage of the seventh
rib, and sometimes likewise that of the sixth, with the xiphoid car-
tilage, is called the costo-xiphoid ligament.

Articulation of the cartilages one with another.—The cartilages
of some of the ribs, viz., from the sixth to the ninth, have a part of
their adjacent borders smoothed inte articular surfaces, which are held
in connection by ligamentous fibres, lined by synovial membranes. Some
of the articular surfaces are occasionally found to be wanting.

Connection of the ribs with their cartilages.—The external
extremities of the cartilages are fixed into the oval depressions on the
ends of the ribs, and the union receives support from the periosteum.

Ligaments of the sternum.—The manubrium, body, and xiphoid
process of the sternum, so long as they are not united by bone, are
connected by intervening cartilage, and by anterior and posterior liga-
ments, which have chiefly a longitudinal direction. The whole sternum

low 12, the anterior sterno-clavicu-

THE COSTO-STERNAL ARTICULATIONS. 143

is much strengthened by thick periosteum, and by the radiating
bands of the costo-sternal ligaments already mentioned.

Fig. 129.—ARrTIcULATIONS OF THE
Srernum, CLAvIcLE, AND Riss,
AS SEEN FROM BEFORE. (A. T.,
after Arnold.) 4

On the right of the middle line
the anterior ligaments are shown ;
on the left side, the front parts of
the clavicle, sternum and costal
cartilages have been removed so as
to display the articular cavities.
1 to 10, the anterior extremities of
the ribs from the first to the tenth
inclusive, on the right side; 1’ to
10’, the costal cartilages of the left
side from the first to the tenth ;
at 1’, the direct union of the first
costal cartilage with the sternum is
shown ; at the sternal ends of the
cartilages marked 2’ to 6’, the small
double synovial cavities-are shown
opened ; between the costal cartilages
on the right side, ligamentous bands
are shown stretching over the inter-
costal spaces ; and on the left side,
by a section, small synovial cavities
are shown between the adjacent
edges of the intercostal. cartilages
from the 5th to the 9th; on the
front of the right half of the
sternum the radiating anterior costo-
sternal ligaments are shown ; lI,
the ensiform process ; 12, 12’, the
inter-clayicular ligament ; and be-

_ lar ligament ; below 12’, the sterno-
clavicular articulation is opened,
‘showing the interarticular fibro-
cartilage and double synovial cavity ;
13, the costo-clavicular or rhomboid
ligament.

Movements of the Ribs.—Each rib is capable of a certain amount of eleva-
tion and depression, and of rotation on an axis passing between its vertebral
and sternal ends. The heads of the ribs are, however, bound down by the
interarticular ligaments so tightly as to prevent any gliding motion at
the attachments of those ligaments, which may therefore be regarded as the
fixed points round which the ribs are moved. When the vertebral column
is bent forwards, the ribs are depressed; and when the column is rotated,
the ribs of that side towards which the upper part of the trunk is turned
are raised, and those of the other side correspondingly depressed. The move-
ment of the tubercle of the rib on the transverse process is of a gliding
description, in the circumference of a circle of which the head of the rib is the
centre ; and as the plane in which the opposed surfaces of the costo-transverse
articulation in most instances lie looks upwards and backwards, the ribs are
moved backwards as well as upwards in inspiration, and forwards and down-
wards in expiration. The combined movements of the thoracie walls in respira-
tion will be described along with the actions of the intercostal muscles. It is
sufficient at present to state that the elevation and rotation of the ribs in inspi-
ration are the main causes of the antero-posterior and transverse enlargement
of the chest. The angular movement is greatest in the upper and least in the
lowest ribs.

144 ARTICULATIONS OF THE HEAD.

TEMPORO-MAXILLARY ARTICULATION.

The lower jaw articulates by its condyle on each side with the smooth
surface of the temporal bone, extending over the part of the glenoid

Fig. 150.—A portion oF THRE-
SKULL wit THE Lower Jaw
AnD Hyorp Bonz, skEN FROM
THE RIGHT AND OUTER SIDE.
(A. T., after Arnold.) 4

1, the external lateral ligament ;
2, a part of the capsule of the
joint ; 3, styloid process ; 4, stylo-
maxillary ligament ; 5, stylo-hyoid
ligament; 6, lesser cornu of the
hyoid ‘bone with some short liga-
ments attaching it to the body
and great cornu; 7, the body ;
8, the great cornu.

fossa in front of the Glaser-
ian fissure and the anterior
root of the zygoma. The
joint is divided by an in-
terarticular fibro-cartilage
into an upper and a lower
synovial cavity.

The external lateral ligament is a short fasciculus of fibres,
attached above to the external surface and the tubercle of the zygoma ;

Fig. 131.—A portion oF THE SKULL
AND LowER JAW WITH HALF THE HYOID
BONE, SEEN FROM THE INSIDE. (A. 7.) 3
The numbers are the same as in Fig.

130 ; 3, the styloid process, detached from

the skull ; 7, the posterior and inner sur-

face of the right half of the body of the
hyoid bone ; 9, the internal lateral lga-

ment of the temporo-maxillary joint ; 10,

the upper opening of the inferior dental

canal,

and below, to the external surface
and posterior border of the neck
of the lower jaw, its fibres being
directed downwards and_back-
wards. Thin and short additional
ligamentous fibres cover the syno-
vial membrane in front and on the
inside, forming an irregular cap-
sule round the joint.

The internal lateral ligament, thin, loose, and elongated, lies at
some distance from the joint. It extends from the spinous process of
the sphenoid bone downwards and a little forwards, to be attached to
the inner border of the inferior dental foramen. Between it and the
lower jaw are placed the external pterygoid muscle, the internal max-
illary artery, and the inferior dental nerve. It has no immediate

‘CEMPORO-MAXILLARY ARTICULATION. 145

connection with the joint, and by some anatomists is not recognised as
a ligament.

The interarticular fibro-cartilage is a thin plate placed between
the articular surfaces of the bones. It is of an oval form, broadest
transversely, thickest posteriorly, and thinnest at its centre, where it
is sometimes perforated. ‘The inferior surface, which is in contact with
the condyle, is concave ; the superior is concayo-convex from before
backwards, conforming with the articular surface of the temporal bone.
Its circumference is connected at the outside with the external lateral
ligament, and anteriorly with the external pterygoid muscle.

©ynovial Membranes.—The synovial membrane which lies between

Fig. 132.—AntTERo-PostEeRIor Fig. 132.
SecTION OF THE TEMPORO-
MaxiLnaRy ARTICULATION
OF THE RIGHT SIDE. (A. T.) §

1, is placed close to the 6 20. =p
articular eminence, and points ee CoD
to the superior synovial cavity *
of the joint; 2, is placed
close to the articular surface
of the head of the lower jaw,
and points to the inferior
synovial cavity of the joint ;
x, is placed on the thicker
posterior portion of the inter-
articular fibro-cartilage.

the interarticular fibro-
cartilage and the glenoid
cavity is larger and looser
than that which is in-
terposed between the
fibro-cartilage and the condyle of the jaw. When the fibro-cartilage
is perforated, the upper and lower synovial cavities necessarily com-
municate with each other. .

The stylo-maxillary ligament is the name given to a strong
thickened band of fibres connected with the cervical fascia extending
from near the point of the styloid process to the posterior border of the
ramus of the jaw, where it is inserted between the masseter and
internal pterygoid muscles. It separates the parotid from the sub-
maxillary gland.

It may be proper also to mention in this place the stylo-hyoid liga-
ment, a thin fibrous cord, which extends from the point of the styloid
process to the lesser cornu of the hyoid bone, and serves to suspend
that bone from the styloid process. A considerable portion of the
stylo-hyoid ligament is sometimes converted into bone in the human
subject, and in many animals it is naturally osseous, constituting the
epithyal bone.

Movements.—The jaw is capable of movements of elevation and depression,
of some degree of lateral displacement, and of protraction and retraction ; but it
is to be observed that when the jaw is depressed, as in opening the mouth, the
condyle advances from the glenoid cavity so as to be placed on the articular
eminence in front of it. The movements which take place in the superior and

VOL, I. L

146 ARTICULATIONS OF THE UPPER LIMB.

inferior compartments of the joint are of different kinds. In the upper the
fibro-cartilage glides backwards and forwards on the temporal bone; in the
lower compartment the condyle rotates on a transverse axis against the fibro-
cartilage. In opening the mouth the two movements are combined: the jaw
and fibro-cartilage together move forwards and rest on the convex root of the
zygoma, while at the same time the condyle revolves on the fibro-cartilage.
When the lower incisors are protruded beyond those of the upper jaw, the move-
ment is confined chiefly to the upper articulation ; and when the same movement
is alternately performed in the joints of opposite sides a horizontal, circular, or
grinding motion is produced. The fibres of the external lateral ligament remain
tight in opening the mouth, owing to the descent of the condyle when it passes
forwards on the articular eminence.

ARTICULATIONS OF THE UPPER LIMB.
THE SCAPULO-CLAVICULAR ARCH.

The supporting arch of the upper limb has only one point of attach-
ment to the skeleton of the trunk, namely, that at the sterno-clavicular
articulation ; the scapula being connected with the trunk only by
muscles.

The clavicle articulates at its inner end with the first bone of the
sternum, and is connected by ligaments to its fellow of the opposite
side and to the first rib. At its outer end it is united to the scapula.

SrERNO-CLAVICULAR ARTICULATION.—The articular surface of the
inner end of the clavicle is considerably larger than the opposing sur-
face of the sternum. Between the two bones an interarticular fibro-
cartilage is interposed.

The anterior sterno-clavicular ligament, broad and consisting of
parallel fibres, passes from the inner extremity of the clavicle in front,
downwards and inwards, upon the anterior surface of the sternum.

The posterior sterno-clavicular ligament, on the posterior
aspect of the joint, is of similar conformation to the anterior ligament,
but is not so broad or strongly marked.

The interclavicular ligament is a dense fasciculus of fibres passing
over the sternal ends of both clavicles. It dips downwards in the
middle, where it is attached to the interclavicular notch of the sternum.

The interarticular fibro-cartilage, nearly circular in its form, and
thicker above and at its margins than at the centre, is interposed be-
tween the articulating surfaces of the sternum and clavicle. Towards
its upper part it is attached to the inner and upper part of the clavicle,
and at its lower edge to the cartilage of the first rib. In the latter
situation it is thin and prolonged outwards, beneath the inferior border
of the clavicle.

Synovial membranes.—In this articulation, as in that of the
lower jaw, there are two cavities lined by synovial membrane, one on
each side of the interarticular fibro-cartilage.

The coste-clavicular or rhomboid ligament does not properly
form part of the sterno-clavicular articulation ; yet it contributes ma-
terially to retain the clavicle in its situation. It is attached inferiorly
to the cartilage of the first rib near its sternal end, and passes obliquely
backwards and upwards, to be fixed to a rough depression at the under
surface of the c\avicle near the sternal end.

SCAPULO-CLAVICULAR ARTICULATIONS.—At its outer end the clavicle
articulates with the acromion and coracoid processes of the scapula.

SCAPULO-CLAVICULAR ARTICULATION. 147

The acromio-clavicular articulation is a synovial joint uniting
the outer extremity of the clavicle with the inner edge of the acromion.
It is supported above by a thick and broad saperior ligament, and
below by an inferior ligament which is not so strong. An inferarticular
Jibro-cartilage 1s frequently present, but is sometimes wanting. It is
wedge-shaped, attached by its base to the superior ligament, and
only partially separates the small oval articular surfaces.

Fig. 133. —Virw FROM BEFORE OF THE ARTICULATIONS OF THE SHOULDER Bowxs.
(A.T.) 3

1, acromio-clayicular articulation ; 2, conoid, and 3, trapezoid part of the coraco-
clavicular ligament ; 4, near the suprascapular ligament ; 5, on the coracoid process,
points to the coraco-acromial ligament ; 6, the capsular ligament of the shoulder joint ;
7, the coraco-humeral ligament ; above 6, an aperture in the capsular ligament through
which the tendon of the subscapularis muscle passes ; 8, tendon of the glenoid head of
the biceps muscle ; 9, right half of the interclavicular ligament ; 10, interarticular fibro-
cartilage of the sterno-clavicular articulation ; 11, the costo-clavicular ligament ; 12 and
13, the cartilage and small part of the second and third ribs attached by their anterior
costo-sternal ligaments.

The coraco-clavicular ligament, which connects the clavicle
with the coracoid process of the scapula, is divisible into two parts.
The conoid ligament, which is the posterior or internal fasciculus, broad
above, narrow below, is attached inferiorly to the inner pars of the root
of the coracoid process, and superiorly to the conoid tubercle of the
clavicle : its fibres are directed backwards and upwards. The trapezoid
ligament, the anterior or external fasciculus, slopes upwards, backwards,
and outwards from the inner border of the coracoid process to an ob-

ligue line extending outwards from the conoid tubercle, on which it is
L 2

148 ARTICULATIONS OF THE UPPER LIMB.

inserted into the clavicle. In the angle between the conoid and trapezoid
ligaments there is frequently present a synovial bursa.

Movements.—The movements allowed at the clavicular articulations are
limited, not so much by the forms of the articular surfaces, as by the costo-
clavicular and coraco-clavicular ligaments, and the position of the thoracic wall.
When the clavicle is forcibly depressed, as in lifting a heavy weight, it presses
upon the first rib, its sternal end rises, and the interarticular cartilage and inter-
clavicular ligament are put upon the stretch. When the shoulders are drawn
backwards and downwards the angle between the clavicle and the upper border
of the scapula is increased by the descent of the scapular arch on the conical
wall of the thorax. In raising and depressing the arm to its full extent, there
is not only vertical movement at the shoulder joint, but also movement at the
sterno-clavicular and acromio-clavicular articulations.

LIGAMENTS OF THE ScAPuLA.—There are two ligaments which
stretch from one part of the scapula to another. I. The coracoid or
suprascapular ligament is a thin, flat band of fibres, attached by
its extremities to the opposite margins of the notch at the root of the
coracoid process, which it thus converts into a foramen for the trans-
mission of the supra-scapular nerve, the corresponding artery most
commonly passing above it. ‘This ligament is frequently converted into
bone. 2. The coraco-acromial ligament, broad, firm, and triangular,
is attached by its broader extremity to the outer edge of the coracoid
process, and by the narrower to the tip of the acromion. Its inferior
surface looks downwards upon the shoulder joint, the superior is covered
by the deltoid muscle. It completes the arch formed by the coracoid
and acromion processes, and gives protection to the shoulder joint.

THE SHOULDER JOINT.

In this articulation the large and hemispherical head of the humerus
is opposed to the much smaller surface of the glenoid cavity of the
scapula. The bones are retained in position, not by the direct tension
of ligaments, which would restrict too much the movements of the joint,
but by surrounding muscles and atmospheric pressure.

Fig. 134. Fig. 134.—Vinw oF THE GLENoIp Cavity AND Lica-
MENTS BETWEEN THE ScAPULA AND CLAVICLE OF
THE RIGHT SIDE. 43

1, glenoid fossa, its cartilaginous surface ; 2, the
glenoid ligament or fibrous border ; 3, the tendon of
the biceps muscle seen in connection with the upper
part of the glenoid fossa and ligament ; 4, upper sur-
face of the coracoid process ; 5 and 6, on the adjacent
part of the clavicle ; 4 to 5, the conoid; 4 to 6, the
trapezoid portion of the coraco-clavicular ligament ; 7,
the apex of the acromion process ; 4 to 7, the coraco-
acromial ligament ; 8, the acromio-clavicular articu-
lation, which is represented as open anteriorly, show-
ing a wedge-shaped interarticular cartilage attached
above to the superior acromio-clavicular ligament ;
x, the inferior acromio-clavicular ligament.

The capsular ligament is attached to the scapula round the
margin of the glenoid cavity, and to the humerus at the place where
the neck springs from the tuberosities and shaft. It extends furthest

THE SHOULDER-JOINT. 149

down the humerus on the internal or inferior aspect, and is strongest
on the superior aspect. It is so lax that the humerus separates
from the glenoid cavity as soon as its muscular connections are detached.
Superiorly and posteriorly the capsule is strengthened by the tendons
of the supraspinatus,_infraspinatus, and teres minor muscles, which
are intimately connected with it as they pass over it to reach the great
tuberosity of the humerus. Anteriorly the tendon of the subscapularis
muscle comes into direct contact with the synovial membrane, which is
prolonged upon it through an oval opening. The insertion of the
capsule is likewise interrupted opposite the hicipital groove, to give
passage to the long tendon of the biceps muscle.

The coraco-humeral, or accessory ligament, is a broad bundle of
fibres extending obliquely over the upper and outer part of the articu-
lation ; it is attached to the root of the coracoid_ process, and thence
descends towards the greater tuberosity of the humerus, intimately
connected with the capsule. A few fibres of the coraco-humeral liga-
ment project into the joint, and are inserted into the inner and upper
part of the bicipital groove ; these have been called the gleno-humeral
ligament, and are supposed to correspond with the ligamentum teres of
the hip joint.

Fig. 135.—A Section THRouGH THE SHouLDER-Jornt, TENDON oF THE BIcePs AND
BictpITaAL GROOVE, SHOWING SOMEWHAT DfAGRAMMATICALLY THE SyNovrAL Cavity oF
THE JomntT, &c. (A.T.) 4

B, OvTLINE OF THE SAME, TO SHOW THE REFLECTION OF THE SyNnoviAL MEMBRANE
OVER THR TENDON.

1, outer part of the clavicle ; 2, the acromial end ; 3, the cavity of the shoulder-joint
close to the upper part of the glenoid head, where there are seen the section of the carti-
lages on the head of the humerus and in the glenoid cavity of the scapula, the glenoid
ligament and the origin of the tendon of the biceps muscle ; 4, the glenoid ligament in the
lower part of the cavity ; 5, the upper part of the capsular ligament and synovial mem-
brane ; 6, the tendon of the biceps as it passes out of the joint into the bicipital groove ;
6’, 6’, the tubular prolongation of the synovial membrane round the tendon ; 7, the
reflection of the synovial membrane on the humerus within the lower part of the capsular
ligament.

The glenoid ligament is a firm fibrous band, about two lines thick
which is fixed to the edge of the glenoid fossa, and thus deepens

150 ARTICULATIONS OF THE UPPER LIMB.

the cavity. The upper part of it is connected with the tendon of the
long head of the biceps muscle, which is also fixed into the upper part
of the glenoid fossa, within the capsule of the joint.

The synovial membrane is reflected uninterruptedly from the
margin of the glenoid cavity on the inner surface of the fibrous cap-
sule to the humerus, but its form is complicated by its relation to the
tendons of the biceps and subscapularis muscles. The long tendon of
the biceps muscle traversing the jomt in its course from the upper
border of the glenoid cavity to the bicipital groove, is enclosed in a
tubular sheath, formed by an offset or process of the synovial mem-
brane, which is continued down upon it beyond the fibrous capsule into
the bicipital groove, and is thence reflected upwards upon it to its
origin, where it again becomes continuous with the synovial mem-
brane of the capsule in such a manner as to preserve the integrity of
the membrane. The bursal prolongation of the synovial membrane on
the tendon of the subscapularis muscle is of variable extent, sometimes
scarcely existing, sometimes forming a considerable pouch on the venter
of the scapula.

Subacromial Bursa.—Superficial to the muscles covering the
top of the joint is a considerable bursa mucosa, by means of which
the contiguous surfaces of the coracoid and acromion processes,
and of the coraco-acromial ligament and deltoid muscle, are lubri-
cated, so as to facilitate the movements of the subjacent head of the
humerus. :

Movements.—Great freedom of movement of the humerus in every direction
is admitted at the shoulder-joint ; but superiorly and posteriorly the extent of
the movement is somewhat limited by the margin of the acromion. When the
arm is raised the great tuberosity of the humerus becomes locked against the
acromion as soon as the position is reached in which the limb lies at right angles
to the trunk, and all further elevation is accomplished by movements in the
sterno-clavicular and acromio-clayicular articulations. The arch formed by the
acromion, the coracoid process, and the deltoid ligament, lined by the sub-
acromial bursa, forms a sort of secondary socket in which the extremity of the
humerus, covered by the tendons inserted into the great tuberosity, revolves, and
against which it is pressed when the weight of the body is made to rest upon the
arms.

ARTICULATIONS OF THE FOREARM AND ELBOW.

The bones of the forearm are united by a superior and an inferior
articulation and an interosseous membrane.

In the SUPERIOR RADIO-ULNAR ARTICULATION the head of the radius is
connected with the small sigmoid cavity of the ulna by the annular
or orbicular ligament. ‘This ligament is a strong band of fibres
attached to the ulna in front and behind, at the extremities of the small
sigmoid cavity, and forming four-fifths of a ring which encircles the
head of the radius and binds it firmly in its situation. The external
_lateral ligament of the elbow is inserted into its outer surface ; its deep
surface is smooth, and is lined by the synovial membrane of the elbow-
joint.

The INFERIOR RADIO-ULNAR ARTICULATION. —The connection between
the semilunar surface of the radius and the lower end of the ulna is
effected by means of a fibro-cartilage, a synovial membrane, and some
scattered ligamentous fibres in front and behind. The triangular fibro-

aS

RADIO-ULNAR ARTICULATIONS. 161

cartilage is a thick plate attached by its base to a ridge separating the
carpal from the ulnar articulating surface of the radius ; and by its

Fig. 136.—TuE UPPER PART OF THE ULNA, WITH THE Fig. 136.
OrBICcULAR LIGAMENT OF THE Rapius. 4
1, upper division of the sigmoid surface on the olecranon ;
2, extremity of the coronoid process ; 5, orbicular ligament.

apex to a depression at the root of the styloid
process of the ulna, and to the side of that pro-
cess. Its upper surface looks towards the ulna,
its lower towards the cuneiform bone, and it
separates the inferior radio-ulnar articulation
from the wrist-joint. The synovial mem-
brane, sometimes called from its looseness mem-
brana saccifornus, extends upwards between the
radius and ulna, and horizontally inwards between
the ulna and triangular fibro-cartilage. When
the fibro-cartilage is perforated, as is occasionally
the case, this synovial cavity communicates with
that of the wrist-joint.

The interosseous membrane or ligament of the forearm is a thin,

Fig. 137.—TuE LOWER PARTS OF THE RADIUS AND
Una, with THE TRIANGULAR FrBRo-CAaRTILAGE
CONNECTING THEM. 2
1, ulna; 2, its styloid process; 3, radius; 4,

articular surface for the scaphoid bone ; 5, that for

the semilunar bone; 6, lower surface of the tri-
angular fibro-cartilage ; * *, a piece of whalebone
passed between the fibro-cartilage and the ulna.

flat, fibrous membrane, the direction of
whose fibres is for the most part ob-
liquely downwards and inwards, from
the interosseous ridge of the radius to
that of the ulna. Its superior border is
placed about an inch below the tubercle
of the radius, leaving an open space above (hiatus interosseus)
through which the posterior interosseous vessels pass. This space is
diminished in size by the round or oblique ligament, a thin, narrow
fasciculus of fibres extending obliquely downwards and outwards from
the coronoid process, to be attached to the radius about half an inch
below the tubercle. Other small bundles of fibres, having the same
direction as the round ligament, are often to be found at intervals,
ecg with the fibres of the interosseous ligament on its posterior
surface.

Movement of the Radius on the Ulna.—The disposition of the annular
ligament allows the head of the radius to rotate freely within it, while the
lower end of the radius, bound by the triangular fibro-cartilage to the styloid
process of the ulna, has a freedom of circumduction round that point, by
which the hand is brought into the prone or the supine position. Thus in
pronation and supination the radius describes a part of a cone, the axis of which

152 ARTICULATIONS OF THE UPPER LIMB.

extends from the centre of the head of the radius to the styloid process of the
ulna.

Fig. 138.—A, Front, anp
Bb, BACK VIEW OF THE
ARTICULATIONS OF THE
Forearm, WRIST AND
Hany. 3}

1, the internal lateral
ligament of the elbow-joint ;
2, the external lateral; 3, the
anterior ; 4, the posterior ;
5, orbicular ligament of the
radius ; 6, interosseous mem -
brane ; 7, oblique or round
ligament; 8, internal lateral
ligament of the wrist ; 9,
external; 10, anterior ; 11,
posterior ; 12, palmar, and
13, dorsal carpo-metacarpal
ligaments ; 14, ligaments
connecting metacarpal bones;
15, transverse metacarpal
ligament ; 16, carpo-meta-
carpal ligament of the
thumb ; 17, lateral liga-
ments connecting the phal-
angeal with the metacarpal
bones ; 18, lateral ligaments
of the phalanges.

THE ELBOW-JOINT.

The lower extremity
of the humerus is in
contact with the ulna
and radius at the
elbow, and forms with
them a hinge-joint.
The greater sigmoid
cavity of the ulna arti-
culates with the troch-
lea of the humerus, so
as to admit of flexion
and extension only; while the cup-shaped depression on the head of
the radius is fitted to turn freely on the rounded capitulum, These
bones are united principally by lateral ligaments.

The internal lateral ligament, composed of diverging and radiat-
ing fibres, is divisible into an anterior and a posterior part. The
anterior part radiates from the front of the internal condylar eminence
of the humerus, and is inserted into the coronoid process, along the
inner margin of the sigmoid cavity. The posterior part, of the same
triangular form, passes from the under and back part of the condylar
eminence downwards to the inner border of the olecranon ; and some
fibres are connected with a small transverse band, which passes over the
notch between the olecranon and the corenoid process.

The external lateral ligament, intimately connected with the
tendinous attachment of the extensor muscles, is shorter and much

THE ELBOW-JOINT. 153

Fig. 139.
A b Cc

Fig. 139.—Ligaments or THE Enpow-Jornt. (A. T.) £

A, from the outer side and behind ; B, from the front ; C, from the inner side and
behind. 1, internal lateral ligament ; 2, external lateral ; 3, the middle strongest part
of the anterior ligament ; 4, orbicular ligament ; 5, posterior, represented as wrinkled
from relaxation in extension. In these figures the round ligament and upper part of the
interosseous membrane are also represented below the elbow-joint.

narrower than the internal. It is attached superiorly to the external
condylar eminence of the humerus, and inferiorly

becomes blended with the annular ligament of the Fig. 140.
radius, some of its hinder fibres being prolonged
to the external margin of the ulna.

Fig. 140.—VerrticaL Awnrtero-Postrr1or SEecTIoN oF THE
Enzow-JoINT THROUGH THE GREATER SigmMorp Cavity
oF THE ULNA AND CORRESPONDING TROCHLEAR SURFACE
oF THE Humerus. (A.T.) 3}

1, cut surface of the humerus; 2, that of the ulna; 3,
posterior part, and 4, anterior part of the synovial cavity of
the joint ; 5, orbicular ligament enclosing the head of the
radius ; 6, tendon of the biceps muscle at its insertion into
the tuberosity ; 7, is at the lower end of the round ligament.

The anterior ligament consists of a thin sheet
of fibres, strongest in its middle part, extending
downwards from above the coronoid pit of the
humerus to the coronoid process of the ulna and
the orbicular ligament.

The posterior ligament is comparatively
thin and weak, and consists of loose and irregular
fibres passing tranversely across the olecranon
fossa of the humerus, and from the sides of that fossa to the

154 ARTICULATIONS OF THE UPPER LIMB.

olecranon process, thus completing the: capsule of the joint be-
hind.

The synovial membrane extends upwards on the humerus so far as
to line the fossee for the coronoid and olecranon processes, and is loose
and vascular in the latter positions. It is also prolonged round the neck
of the radius, and lines the annular ligament.

Movements.—Flexion and extension are the only movements which can take
place between the humerus and ulna; and these are limited by the locking of
the coronoid and olecranon processes in the respective fossz of the humerus
which receive them. The path of motion is in a nearly vertical plane, with a
direction slightly outwards. The inner lip of the trochlea being prominent
below, forms an expansion which corresponds to an inward projection of the
coronoid part of the ulnar surface, and is only brought into use in flexion ; and
the outer lip of the trochlea, being everted at the upper and back part, forms a
surface which is only in use in complete extension, and which then corresponds
to a surface on the outer aspect of the olecranon, which comes into contact with
no other part of the humerus. In flexion and extension the radius moves by its
cup-shaped head upon the capitulum, and on the groove between that process
and the trochlea, by a ridge internal to the cup. It is most completely in contact
with the humerus in the position of semi-flexion and semi-pronation. In full
extension and supination, the anterior margin of the head of the radius is barely
in contact with the inferior surface of the capitulum. In full flexion the margin
of the head of the radius rests against the pit above the capitulum.

THE WRIST-JOINT AND ARTICULATIONS OF THE HAND.

THE RADIO-CARPAL ARTICULATION, or wrist-joint, is formed between
the radius and triangular fibro-cartilage above, and the scaphoid,
semilunar and cuneiform bones below. ‘The superior surface, concave
both transversely and from before backwards, is subdivided by linear ele-

vations into three parts corresponding to the three bones below, the
innermost part being formed by the fibro-cartilage. The inferior
surface, convex in both directions, is prolonged further down upon the
carpal bones behind than in front.

The internal lateral ligament is a rounded cord passing directly
downwards from the extremity of the styloid process of the ulna, to the
cuneiform bone ; it also sends some fibres to the anterior annular
ligament and the pisiform bone.

“The external lateral ligament extends from the styloid process of
the radius to a rough surface on the outer side of the eu ae bone,
some of its fibres being prolonged to the trapezium, and also to the
anterior annular ligament of the wrist.

The anterior ligament, broad and membranous, consists partly of
fibres which have a nearly transverse direction, partly of others which
diverge as they descend from the anterior border of the radius to the
scaphoid, semilunar, and cuneiform benes ; some of them are continued
to the os magnum.

The posterior ligament extends obliquely downwards and inwards,
from the extremity of the radius, to the posterior surface of the first
row of the carpal bones, especially the cuneiform bone ; its fibres are
prolonged some distance on the surface of the carpal bones.

The synovial membrane is reflected from the radius and the
triangular fibro-cartilage, on the surrounding ligaments, and, after
lining these, passes to the margins of the opposed surface of the car pal
bones.

THE WRIST-JOINT. 155

Tue CarpaL ArrTICcULATIONS—The bones of the carpus, the pisiform
excepted, are so arranged in two rows, that while only slight movement
can take place between the members of each row, a considerable amount
of movement is possible between the two rows. The surface presented
by the first row to the second is concave both transversely and from
before backwards in the greater part of its extent, but at its outer side
it is bounded by the convex part of the scaphoid bone. The opposing
surface of the second row is concavo-convex from without inwards, the
concavity being formed by the trapezium and trapezoid, the convexity
by the os magnum and unciform bone.

Fig. 141.
A B

Fig. 141, A.—Dorsan vinw oF THE DEEPER LIGAMENTS OF THE WRIST-JOINT, AND OF
THE CARPAL AND Carpo-Mrracarpat Articunarions. (A. T., after Arnold). 4

1, lower part of the ulaa ; 2, external lateral ligament of the wrist-joint ; 3, internal ;
near it descending cbliyuely to 6, from the radius, the dorsal radio-carpal ligament ;
4 to 5, transverse dorsal ligaments of the first row; 4, is on the scaphoid; 5, on the
semilunar bone ; 6, cuneiform bone, with the attachment of the dorsal radio-carpal liga-
ment ; 7, trapezium ; 8, trapezoid ; 9, os magnum ; 10, unciform ; 11 to 15, first to fifth
metacarpal bones ; 7 to 8, 8 to 9, and 9 to 10, transverse dorsal ligaments of the second
row of carpal bones ; + to 8, 4 to 9, 5 to 9, and others, dorsal ligaments between the first
and second row ; 8 to 12, 9 to 13, and others, dorsal ligaments from the second row to
the metacarpal bones ; between the metacarpal bones, from 11 to 15, the dorsal inter-
metacarpal ligaments.

Fig. 141, B.—Pauwar view or toe Ligaments or THE WRist-JoINrT, AND OF THE
CarpaL AND Carpo-MrracarpaL Articunations. (A. 7.) §

The anterior radio-carpal ligament has been removed : 1, anterior ligament of the lower
radio-ulnar articulation ; 2, external, and 3, internal lateral ligament of the wrist-joint ;
4, scaphoid bone ; 5, semilunar ; 6, cuneiform ; 7, pisiform, with the tendon of flexor
carpi ulnaris attached : 4 to 5, and 5 to 6, palmar transverse ligaments of the first row ;
8, external lateral ligament between the first and second row of carpal bones ; 9, trape-
zium (the trapezoid is not numbered) ; 10, os magnum ; 11, hooked process of the unciform
bone, 9 to 10, 10 to 11, and others, transverse palmar ligaments of the second row ; 4 to
10, and 6 to 10, some of the palmar ligaments uniting the two rows, converging on the os
magnum ; 7 to 11, ligament from the pisiform bone to. the unciform process ; 7 to 16,
ligament from the pisiform to the fifth metacarpal bone ; 12, external ligament of the
first carpo-metacarpal articulation, the internal of which is also shown ; 13, 14, 15, 16,
the proximal ends of the second to the fifth metacarpal bones, on which the palmar trans-
verse, and on three of them, a set of piso-metacarpal ligaments are shown.

156 ARTICULATIONS OF THE UPPER LIMB.

The two rows of carpal bones are united by dorsal, palmar, and
lateral ligaments. The lateral ligaments are placed one at the radial,
the other at the ulnar border of the carpus ; the former connects the
scaphoid bone with the trapezium, the latter the cuneiform with the
unciform. The dorsal ligaments consist of fibres passing in various
directions ; the palmar ligaments are chiefly composed of fibres converg-
ing towards the cs magnum.

The bones of the first row, the pisiform bones excepted, are
united by interosseous and by dorsal and palmar ligaments. The
interosseous ligaments, placed on the sides of the semilunar bone on a
level with its superior surface, connect it with the scaphoid and cunei-
form bones, thus completing the inferior wall of the radio-carpal joint.
The dorsal and palmar ligaments, each two in number, extend trans-
versely on the dorsal and palmar surfaces from the scaphoid bone to the
semilunar, and from the semilunar to the cuneiform.

The bones of the second row are connected by similar means. The
dorsal and palmar ligaments, each three in number, pass transversely
between the contiguous bones. The interosseous ligaments are gene-
rally three (but sometimes only two) in number, a strong ligament
being placed between the os magnum and unciform bones, another
between the trapezoid and trapezium, and a slender ligament between
the os magnum and trapezoid. A small interosseous ligament is also
sometimes found between the os magnum and the scaphoid. (Fig. 142.)

The synovial cavity of the carpal articulations is extensive and
complicated. Passing between the two rows of carpal bones, it sends

Fig. 142.—Transverse Section oF THE Sy-
NOVIAL CAVITIES OF THE INFERIOR Raprio-
Unwnar, Rapro-Carpat, INTERCARPAL, AND

Carro-MeracarPan ARTICULATIONS. (A. T.)
1

Oo

1, points to the triangular fibro-cartilage
below the ulna ; 2, placed on the ulna, points
to the cavity of the sacciform synovial mem-
brane ; 3, external lateral, and 4, internal
lateral ligament, and between them the synovial
cavity of the wrist ; 5, scaphoid bone ; 6, semi-
lunar ; 7, cuneiform ; 8, 8, upper portion, and
8’, 8’, lower portion of the general synovial
cavity of the intercarpal and carpo-metacarpal
articulations ; between 5 and 6, and 6 and 7,
the interosseous ligaments are seen separating
the carpal articular cavity from the wrist-
joint ; between the four carpal bones of the
lower row, and between the magnum and
scaphoid, the interosseous ligaments are also
shown ; the upper division of the synovial
cavity communicates with the lower between
10 and 11, and between 11 and 12; x, marks
one of the three interosseous metacarpal liga-
ments ; 94, separate synovial cavity of the first
carpo-metacarpal articulation ; 13, first, and 14, fifth, metacarpal bone.

Norr. It is to be observed that in this figure, and in others of a like kind which
Lepresent the joint-cavities, the white or black lines indicating the synovial membranes
are, for the sake of clearness, generally represented as passing over the surfaces of the
articular cartilages, although this is not the case in nature. These lines therefore must
be held to represent merely the whole continuity of the articular, or, as they are often
called, the synovial surfaces.

ARTICULATIONS OF THE HAND. 1907

likewise two processes between the three bones of the first row, and
three between the four bones of the second. It is further continued
downwards into the inner four carpo-metacarpal and three intermeta-
carpal articulations. In some rare cases there is continuity with the
synovial membrane of the wrist-joint, by deficiency of one of the
interosseous ligaments between the carpal bones.

The pisiform bone is articulated by a fibrous capsule and synovial
membrane with the cuneiform bone. Inferiorly it is united by two
strong ligaments with the unciform and fifth metacarpal bones, and is
sometimes also connected with other metacarpal bones ; superiorly it
receives the tendon of the flexor carpi ulnaris muscle. The synovial
cavity is usually distinct, but sometimes communicates with that of the
radio-carpal articulation.

The anterior annular ligament of the wrist is a strong and
thick band, which extends from the prominences made by the trapezium
and scaphoid bone on the radial side of the carpus, directly across to the
pisiform bone and unciform process, and converts the transverse arch of
the carpus into a ring through which the flexor tendons of the digits
pass into the hand.

The posterior annular ligament, placed at the back of the wrist,
is only a thickened part of the aponeurosis of the forearm. It extends
from the lower part of the radius, at its outer border, to the inner part
of the cuneiform and pisiform bones and serves to bind down the
extensor tendons.

CARPO-METACARPAL AND INTERMETACARPAL ARTICULATIONS

: ig. 148.
Fig. 143.—GenrraL VIEW OF THE ARTICULATIONS Fig. 143
OF THE WRIST AND HAND FROM BEFORE. 4

1, lower part of the interosseous membrane ; 2,
and from that point across the lower end of the
radius, the palmar radio-carpal ligaments ; 3, sca-
phoid bone; 4, pisiform ; 5, trapezium ; 6, unci-
form; 7, os magnum, with most of the deeper
ligaments uniting these bones ; I, first metacarpo-
phalangeal articulation with its external lateral
ligament ; IL to VY, transverse metacarpal liga-
ment: in the several phalangeal articulations the
lateral ligaments are shown; in the first the
external only is visible.

The four inner metacarpal bones
are bound together at their distal ex-
tremities by thin fibres passing between
them on their palmar aspect, and consti-
tuting the transverse ligament. At their
proximal extremities they are united to
one another and to the carpal bones in
articulations, the common synovial lining
of which is derived from that of the carpal
joint. In these articulations the four
metacarpal bones are bound together by
three dorsal, and three palmar, and by
strong iterosseous ligaments. There are
also dorsal ligaments uniting these meta-

carpal bones with the carpus, each having two such ligaments expect

158 ARTICULATIONS OF THE UPPER LIMB.

the fifth. Thus to the second, or that of the forefinger, a thin fasci-
culus of fibres passes from the trapezium, and another from the
trapezoid bone ; the third receives one from the trapezoid, and from the
os magnum; the fourth from the os magnum and also from the unci-
form; but the fifth is connected’ with the unciform only. The palnar
ligaments are not so well defined ; there is a single band to each bone,
except that of the little finger. There is likewise an interosseous band
in one part of the carpo-metacarpal articulation, connecting the lower
and contiguons angles of the os magnum and unciform to the adjacent
angle of the third metacarpal bone. This ligament is usually sur-
rounded by a part of the general synovial membrane, but sometimes it
separates the cavity between the unciform and two inner metacarpal
bones from the rest of the joint.

The first metacarpal bone is unconnected with the others, and is
articulated with the trapezium by an external and an internal ligament,
a capsular investment, and a distinct synovial membrane.

METACARPO-PHALANGEAL AND INTERPHALANGHAL ARTICULATIONS. sh

The rounded head of each of the last four metacarpal bones, being re-
ceived into the slight hollow in the extremity of the first phalanx, is
maintained in its position by two lateral ligaments,
an anterior ligament, and a synovial membrane.

The lateral ligaments consist of strong fasci-
culi of fibres, on each side of the joint, from the
metacarpal bone to the contiguous extremity of the
phalanx. The direction of the fibres is downwards
and forwards.

Fig. 144.—Lonerrupinan Antero-Posterion SECTION THROUGH
THE LOWER PART OF THE Raptus, Semmnunar Bonz, Os
Maaenum, Meracarran Bone anp PHALANGES OF THE MIDDLE
Fincer, 20 SHOW THE SHAPE OF THE ARTICULAR SURFACES
AND SYNOVIAL CAVITIES BETWEEN THESE SEVERAL Dongs.
(ASST) ee
1, synovial cavity of the wrist-joint ; 2, intercarpal cavity ;

3, carpo-metacarpal cavity; 4, metacarpo-phalangeal cavity ;
5 and 6, phalangeal cavities; 4’, 5’, and 6’, the palmar fibro-
cartilaginous plates whith are attuched to the base of the several
phalanges ; 7, indicates the place of the tendons of the long
flexor muscles ; 8, a transverse section of the anterior annular
ligament ; 9 and 10, transverse retinacula, or vaginal ligaments
of the flexor tendons on the first and second phalanges.

The anterior or palmar ligament, or rather
fibrous plate, occupies the interval between the
lateral ligaments on the palmar aspect of each
joint ; it is a thick and dense fibro-cartilaginous
structure, which is firmly united to the phalanx but
loosely adherent tothe metacarpal bone. It is con-
tinuous at each side with the lateral ligament, so
that the three form one undivided structure which
covers the joint, except on the dorsal aspect. Its
palmar surface is grooved for the flexor tendon,
whose sheath is connected to it at each side ; the other surface, looking
to the interior of the joint, is lined by the synovial membrane, and

SACRO-VERTEBRAL ARTICULATION. 159

supports the head of the metacarpal bone. In the joint of the
thumb there are two sesamoid bones, one situated at each side, which

are connected with its ligaments.

A synovial membrane is present in each joint, and inyests the
surface of the ligaments which connect the bones.

The interphalangeal articulations are formed on the same plan ag
that which obtains in the articulations between the bases of the proximal
phalanges with the metacarpal bones.

Movements of the Wrist and Fingers.—In the radio-carpal and common
carpal articulations, there is allowed not only flexion and extension, but a
certain amount of lateral bending. The superior articular surfaces of both
ranges of carpal bones being prolonged further on the dorsal than on the palmar
aspect, over-extension is allowed in both joints to some degree. In over-exten-
sion the opposing surfaces are most perfectly adapted to each other; in flexion
they are least so. The kind of movement which is allowed between the carpal
and metacarpal bones is best illustrated by placing the hand in such a position
that the weight of the body is rested upon the-open palm. The metacarpal
range, which naturally is concave towards the palm, is flattened ; and the inter-
osseous and palmar metacarpal ligaments are thus tightened, while a slight
separation of the opposed surfaces of the bones takes place ; so also the palmar
carpo-metacarpal ligaments are tightened, and both palmar and interosseous
ligaments of the second range of carpal bones. The convex part of the os
magnum and unciform bone, fitted in these circumstances into the concavity of
the first range, is a little wider than the part usually in contact with it; and
thus, while the bones of the first range are separated from the palmar side, those
of the second range are pressed still more apart from the distal aspect. The
whole ‘arrangement secures elasticity. The fourth and fifth metacarpal bones,
being more movable at their carpal articulation than the second and third, bend
forward very distinctly in shutting the hand, thus rendering the palm more
hollow, and bringing the tips of the fingers more closely together. At the
phalangeal articulations the only movements allowed are flexion and extension,
while over-extension is prevented by the ligamentous structures in front of the
joints. At the metacarpo-phalangeal articulations abduction and adduction
are allowed chiefly in the extended position. In the articulation of the meta-
carpal bone of the thumb with the trapezium every movement is allowed except
rotation, which is prevented by the shape of the articular surfaces,

ARTICULATIONS OF THE PELVIS.

ARTICULATION OF THE PELVIS WITH THE LAST LUMBAR VERTEBRA.
—The fifth lumbar is united to the first sacral vertebra by anterior and
posterior ligaments of the body, capsular ligaments of the articular
processes, ligamenta subflava of the arch, interspinous ligaments, and
by an intervertebral plate, all of which are similar to those between the
vertebree above. It is also attached to the pelvis by two other liga-
ments, as follows.

The sacro-vertebral ligament extends obliquely from the tip of the
transverse process of the last lumbar vertebra downwards to the de-
pressed lateral part of the base of the sacrum; its form is triangular,
and its fibres diverge as they descend, some of them joining the anterior
sacro-iliac ligament.

The ilio-lumbar ligament is extended horizontally between the
summit of the transverse process of the last lumbar vertebra and the
iliac crest of the innominate bone; it is inserted into the latter at the

160 ARTICULATIONS OF THE PELVIS.

back part of the iliac fossa, where its fibres expand somewhat, so as to
give it a triangular form.

ARTICULATION OF THE SACRUM AND Coccyx, AND OF THE PIECES
or tHE Coccyx.—-These articulations are effected by an anterior liga-
ment, consisting of irregular fibres placed in front of the bones, a pro-
longation of the anterior common ligament of the vertebre; by a
posterior ligament more strongly marked, the fibres of which descend
upon the bones of the coceyx from the margin of the inferior orifice of
the sacral canal; by fibrous bands extending between the cornua of the
sacrum and coccyx; and by intervertebral discs between the con-
tiguous surfaces of the bones.

A distinct cavity is stated by Cruveilhier (‘‘ Anatomie descriptive,” tom. i.
p. 305. Paris, 1862), to be present in the centre of the disc in those cases in
which the coccyx is freely moveable. This is in conformity with the more recent
observations of Luschka on the other intervertebral discs. In the male, after
middle life, the union between the sacrum and coccyx, and between the pieces
of the latter, is usually ossific. In the female this change does not generally

Fig. 145.

Fig. 145.—Anrricunarions or tHe Prnyis AND Hrp-Jort, sEEN rkoM BEFORE. THE
ANTERIOR HALF OF THE CApsuLAR LIGAMENT oF THE Lerr Hrp-JoInt HAS BEEN
REMOVED, AND THE FEMUR ROTATED ouTWARDS. (A. T.) 3

1, 1, anterior common ligament of the bodies of the vertebre passing down to the
front of the sacrum and coccyx ; 2, ilio-lumbar ligament ; 3, anterior sacro-iliac liga-
ment ; between 2 and 3, on the right side, the sacro-vertebral ligament is shown, but not
with sufficient distinctness ; 4, placed in the great sacro-sciatic foramen, points to the
lesser sacro-sciatic ligament ; 5, a portion of the great sciatic ligament ; 6, the anterior
ligament of the symphysis pubis ; 7, the obturator membrane ; 8, the capsular ligament
of hip-joint : the figure is placed on its ilio-femoral band; 9, the upper part of the
divided capsular ligament of the left hip-joint near the place of its attachment to the
border of the acetabulum ; 10, placed on the os pubis of the left side above the trans-
verse ligament of the acetabular notch. The head of the femur is withdrawn partially
from the socket, so as to show the round ligament stretched from the transverse
ligament.

SACRO-ILIAC ARTICULATION. 161

occur till a more advanced age; the pieces of the coccyx uniting one to another
in the first place, and the joint between the sacrum and coccyx not ossifying till
old age. The mobility seems to increase during pregnancy.

THE SACRO-ILIAC ARTICULATION, often named the sacro-iliac syn-
chondrosis, is formed between the auricular surfaces of the sacrum and
ilium, which are bound together by a plate of cartilage, and by strong
ligaments (see fig. 148).

The auricular cartilaginous plate unites the bones with great firm-
ness. When the ilium and sacrum are forcibly torn asunder, this plate
usually separates into two layers, one of which adheres to the surface of
each bone. In some instances a small cavity naturally exists between
these two plates of cartilage, and in advanced life small spaces con-
taining glairy fluid are liable to be formed between them. Even when
separate in part, however, these plates are very closely applied, and
admit only a limited amount of movement. The cavity of this articu-
lation becomes more apparent, and the ligaments somewhat looser before
parturition.

The posterior sacro-iliac ligament consists of a large number of
strong irregular fibres extending across the interval between the pos-

EE
oy IQ

Fig. 146.—Licaments or tan Peryis anp H1r-Jont. snen FRO BEHIND, FROM A
FemaLe Supsect. (A. 7.) 3

1, ilio-lumbar ligament : above it the last lumbar intertransverse ligament ; 2, posterior
sacro-iliac ligaments, the short and the oblique ; 3, great sacro-sciatic ligament ; 4, lesser
sacro-sciatic ligament ; 5, obturator membrane; 6, posterior ligament of symphysis
pubis ; 7, 7, continuation of supraspinous ligaments from the lower lumbar vertebre
over the sacral spines; 8, transverse process of last lumbar vertebra, to which from
above is seen descending the last intertransverse ligament, and from below ascending the
sacro-vertebral ligament ; 9, posterior surface of the capsular ligament of the hip-
joint. The posterior ligaments passing between the sacrum and coccyx are also partially
shown.

VOL. I. M

162 ARTICULATIONS OF THE PELVIS.

terior rough portion of the lateral surface of the sacrum and that part
of the ilium which projects beyond the dorsum of the sacrum. A
superficial band extending downwards from the posterior superior
iliac spine to the third or fourth piece of the sacrum, in a direction
different from the other fibres, is distinguisned as the oblique sacro-tliac
ligament.

The anterior sacro-iliac ligament consists of thin irregular fibres
passing between the sacrum and os innominatum on their pelvic
surfaces.

THE SACRO-SCIATIC LIGAMENTS.—The posterior, or great sacro-
sciatic ligament, broad and triangular, assists in closing the lower aper-
ture of the pelvis. Its base is attached to the postero-inferior iliac spine
and to the side of the sacrum and coccyx; whilst its apex is fixed along
the inner surface of the ischial tuberosity, where it expands somewhat,
and sends upwards and forwards along the margin of the ischial ramus
a faleiform process, the border of which is continuous with, and forms the
inferior attachment of, the obturator fascia.

The anterior, or small sacro-sciatic ligament, much shorter
and thinner than the preceding one, in front of which it lies, is also
triangular in form, and is attached by its base to the side of the sacrum
and coccyx, where its fibres are blended with those of the great liga-
ment ; and, by its apex, to the_spine of the ischium.

Foramina. Between the upper border of the great sacro-sciatic
ligament and the innominate bone, is a large space subdivided by the
small sacro-sciatic ligament. The part which lies above this ligament
is a large oval opening, named the great sacro-sciatic foramen. It
transmits the pyriform muscle and the gluteal and sciatic vessels and
nerves. The part between the greater and lesser sacro-sciatic liga-

Fig. 147. Fig. 147.—Riaut waLr or A Fremaue
PELVIS, SEEN FROM THE INNER SIDE.
(A.T.) 2

1, supraspinous ligaments descend-
ing to the sacrum from 2, 2, the
lumbar spinous processes; 3, 4, the
lumbar and sacral spinal canal, with
its periosteal lining; 5, placed on
the ilium above the anterior sacro-
iliac ligament ; 6, placed in the great
sacro-sciatic foramen, points to the
lesser sacro-sciatic ligament ; 7, greater
sacro-sciatic ligament, with 7’, its con-
tinuation over the inner border of the
tuberosity of the ischium ; 8, a portion
of the wall of the cotyloid cavity, re-
moved so as to give a view from the
inside of the head of the femur ; 9, the
round ligament put upon the stretch,
the femur being partially flexed and
adducted ; 10, the inner part of the
capsular ligament relaxed; 11, the
shaft of the femur.

ments, much smaller in size,
and bounded in front by the
smooth surface between the
spine and tuberosity of the ischium, is the small sacro-sciatic foramen,

THE HIP-JOINT. 163

through which pass the obturator internus muscle and the internal
pudic vessels and nerve.

The pubic articulation, or symphysis pubis, is the connection of the
pubic bones in front, and is effected by fibro-cartilaginous plates and
ligaments. The adjacent surfaces of bone are each coated with car-
tilage, and to this is attached the fibro-cartilage which unites them.
The fibro-cartilage is thicker and stronger in front than behind, and
generally contains a synovial cavity towards the upper and back part of
the joint. The ligaments are named anterior, posterior, superior, and
inferior. The anterior pubic ligament consists of irregular fibres
passing obliquely across from bone to bone in front of the symphysis.
The superior and posterior ligaments consist of only a few fibres on
the upper and back part of the articulation, The inferior or subpubic
ligament, thick and triangular, is attached to the rami of the pubic
bones, giving smoothness and roundness to the subpubic angle, and
forming part of the outlet of the pelvis.

The obturator membrane, or ligament, is a fibrous septum attached
to the border of the thyroid foramen, which it closes, except at the
upper and outer part of its circumference, where a small oval canal is left
for the obturator vessels and nerve. The membrane is fixed accurately
to the bony margin at the upper and outer sides of the foramen, and to
the posterior surface at the inner side. The obturator muscles are
attached to its surfaces.

Movements.—In ordinary circumstances there is very little movement allowed
between the bones of the pelvis. In the erect posture the sacrum is thrown so
much backwards that none of the advantage of the key-stone of an arch is
obtained by the tapering of its form from base to apex. It is only by the
sinuosities of its auricular surfaces that it directly presses on the hip-bhones ; and
as the width of the bone rather diminishes at the upper or ligamentous part, the
principal strain is borne by the posterior sacro-iliac ligaments, from which the
sacrum is in great measure suspended (see fig. 148). The space which might be
gained by the small amount of movement which is allowed between the bones
of the pelvis in the ordinary state is increased during parturition in this way,
that the lower part of the sacrum being pressed backwards, the wider part of
the wedge formed by this bone is forced farther between the ossa innominata,
so as to separate them to a greater degree, and thus to increase the capacity
of the pelvis. During pregnancy, also, a slight amount of separation may occur at
the symphysis pubis from relaxation of the connecting parts. (See Wood, article
“Pelvis” in “Cycloped. of Anat. and Physiol.;” Zaglas, in Monthly Journ. of
Med. Science, 1851; J. M. Duncan, in Dublin Quart. Journ. of Med. Science,
1854, and Edin. Med. Journ. 1855 ; Struthers, ‘“‘ Anat. Obsery.”)

ARTICULATIONS OF THE LOWER LIMB.
THE HIP-JOINT.

This is a large ball and socket joint, in which the globular head of
the femur is received into the acetabulum or cotyloid cavity of the
innominate bone. The articular surface of the acetabulum is formed
by a broad riband-shaped cartilage occupying the upper and outer part,
and folded round a depression which, extending from the notch, is
hollowed out in the bottom of the cavity, and is occupied by delicate
adipose tissue covered with synovial membrane, the so-called synovial
or Haversian gland. - The articular surface of the femur presents a
little beneath its centre a pit in which the round ligament is attached,

Mm 2

164 ARTICULATIONS OF THE LOWER LIMB.

Fig. 148—Transverse Opiiqur SEcTIoN or THE PeLvis AnD Hip-JoInt, CUTTING THE
FIRST SACRAL VERTEBRA AND THE SYMPHYSIS PUBIS IN THEIR MIDDLE, FROM A MALE
SuBJECT OF ABOUT NINETEEN YEARS oF AcE. (A. T.) 4

1, the first sacral vertebra ; 2, the divided ilium ; 3, the posterior sacro-iliac liga-
ments ; 4, 4, the sacro-iliae synchondrosis, with a slight separation between the two
plates of cartilage ; 5, the anterior sacro-iliac ligament; 6, the lesser sacro-sciatic
ligament ; 7, greater sacro-sciatic ligament ; 8, placed in front of the symphysis pubis,
in the cut surface of which the small median cayity, the adjacent fibro-cartilaginous
plates, and the anterior and posterior ligamentous fibres are shown; 9, the lower part of
the obturator membrane ; 10, the cartilaginous surface of the cotyloid cavity, through
the middle of which the incision passes transversely, dividing the round ligament and the
synovial fat of the depression ; 11, the cotyloid ligament ; 12, the round ligament con-
nected with the transverse part of the cotyloid ligament ; 13, placed on the cut surface
of the head of the left femur near the depression where the round ligament is attached ;
14, 14’, the upper and lower parts of the capsular ligament and synovial capsule.

The cotyloid ligament forms a thick fibro-cartilaginous ring round

but pass obliquely from without inwards over its margin, one extremity
being attached to the outer, the other to the inner surface.
At the cotyloid notch the fibres of the hgament are continued from

THE HIP-JOINT. 166

side to side, so as to render the circumference complete, and deeper
transverse fibres are superadded, from which circumstance, as well as
from being stretched across from one margin of the notch to the other,
this part is called the transverse ligament. Beneath it an interval is
left for the admission of the articular vessels.

The interarticular or round ligament (ligamentum teres) is a strong
fasciculus surrounded by synovial membrane, implanted by one extremity,
which is round, into the fossa in the head of the femur ; by the other,
which is broad, flat, and bifid, into the margins of the cotyloid notch,
where its fibres become blended with those of the transverse li@anrent.
It rests on the fat in the depression of the acetabulum. ae

The capsular ligament or membrane surrounding the joint is
attached superiorly to the margin of the cotyloid cavity, and inferiorly
to the neck of the femur. At its cotyloid attachment the capsule arises,
above and behind, from the bony margin outside the attachment
of the cotyloid ligament, having its inner surface in close contact
with that hgament; in front it arises from the outer aspect of the
cotyloid ligament near its base, and at the notch it is similarly attached
to the transverse ligament. At its femoral attachment the capsule
extends anteriorly to the intertrochanteric line, superiorly to the root
of the great trochanter, posteriorly and inferiorly to the junction of the
middle and external thirds of the neck. ‘The fibres of which the cap-
sulé consists run In two directions, circularly and longitudinally. The
circular fibres are found in the middle of the lower wall of the capsule,
gathered into a thick broad band (Zona orbicularis, Henle,) which as it
extends upwards spreads out so as to form a tolerably even layer over
the front and upper part of the joint. Behind, these fibres again form
a band which for about a finger’s breadth next the neck of the femur
complete the capsule. The circular fibres are embedded to some extent
in the longitudinal fibres, except posteriorly, where the latter are almost
absent, being represented by a few scattered fibres which support the
synovial membrane, and attach the circular fibres to the neck of the bone.
In other parts of the capsule the longitudinal fibres form thick bands,
certain of which from their greater size and strength are distinguished
as accessory ligaments. ‘he chief of these are formed on the anterior and
superior aspects of the capsule. The ¢lio-femoral ligament consists of
two diverging bands of fibres, which arise from the anterior inferior
iliac spine, and pass obliquely downwards over the front of the joint.
The inner of these bands passes almost vertically to the root of the
small trochanter ; the outer to the upper end of the anterior inter-
trochanteric line. In the triangular space thus left between the bands,
the deeper fibres of the capsule are seen. On the superior aspect of the
joint the outer band of the ilio-femoral ligament is joined by another
band of fibres (ilio-trechanteric) which is attached to the ilium, above
the origin of the long head of the rectus femoris muscle, and to the
root of the great trochanter on its anterior aspect. To the under
surface of the capsule, a broad and strong band of fibres (éschio-capsular)
passes from the furrow.on the ischium below the acetabulum to end in
the circular fibres. In front and below may be also found a number of
scattered fibrous bundles, which converge to the capsule from the ilio-
pectineal eminence, from the margin of the obturator foramen, and from
the obturator membrane, and to which Henle has given the name of
pubo-femoral ligament. Besides these the capsule receives other strength-

166 ARTICULATIONS OF THE LOWER LIMB.

ening bands from the tendons of neighbouring muscles, in front from
the ilio-psoas, above from the long head of the rectus femoris, behind
from the gluteus minimus, and below from the obturator externus.

From the inside of the capsule the inner layers of fibres are reflected
upwards from their insertion upon the neck of the femur to the articular
cartilage, forming a surface partly level and partly raised into longi-
tudinal folds called retinacula (Henle).

The synovial membrane of the joint is reflected from the neck of
the femur to the inner surface of the capsule, thence to the inner surface
of the cotyloid ligament and to the pad of fat in the bottom of the ace-
tabulum, from which it is further prolonged as a tubular investment
upon the round ligament. It frequently communicates through an
opening in the anterior wall of the capsule, with a synovial bursa placed
beneath the tendon of the ilio-psoas muscle.

Movements.—The movements allowed at the hip-joint are extension, flexion,
abduction, adduction, circumduction, and rotation. Extension is limited by the
anterior fibres of the capsular ligament, and the ilio-femoral band: flexion is
limited only by the contact of the neck of the femur with the acetabulum,
Abduction is controlled by the pubo-femoral bands, and by the lower part of the
capsule ; adduction by the ilio-trochanteric band and by the upper part of the
capsule. The round ligament is put upon the stretch when the thigh is partially
flexed and adducted; it therefore resists dislocation upwards and backwards on
the dorsum ilii, which is, notwithstanding its presence, the most frequent kind
of displacement. The round ligament is also put upon the stretch in the position
of flexion and external rotation. The swinging antero-posterior movement of
the femur, as in walking or running, is effected by rotation of the head of the
bone in the hip-joint. In the erect attitude, as a vertical line passing through the
centre of gravity of the trunk falls behind the centres of rotation in the hip-
joints, the pelvis tends to fall backwards by over extension of the hip-joints, but
as this is prevented by the tightening of the capsule in front, the maintenance
of the erect attitude, without muscular effort, is partly due to this mechanism
of the hip-joint.

THE KNEE-JOINT.

The articular surfaces of this complicated joint are the condyles of
the femur and tibia, with fibro-cartilages interposed, the articulating
surface of the patella, and the patellar surface of the femur. The action
is mainly that of a hinge-joint. The joint is strengthened superficially
by fibrous coverings derived from the muscular tendons and apo-
neuroses. ‘I'he ligaments which have received special names are the
following.

The internal lateral ligament, long and flat, connects the internal
tuberosity of the femur with the inner tuberosity and the hinder border
of the tibia, on the shaft of which it descends for some distance. Supe-
riorly its deep surface rests on the articular synovial membrane; in the
middle it is attached to the internal semilunar cartilage ; and below the
head of the tibia the anterior slip of insertion of the semimembranosus
muscle passes between the ligament and the bone.

The external lateral ligament is a rounded cord, which extends
from the external tuberosity of the femur to the head of the fibula. Its
internal surface corresponds with the tendon of the popliteus muscle
and the inferior external articular vessels. The tendon of the biceps
flexor cruris muscle is frequently divided into two by this ligament, and
between the ligament and the tendon there is a synovial bursa. Further

THE KNEE-JOINT, 167

back is another band, the short external lateral ligament, the arrangement
of which is more variable ; it is often connected with the tendon of
the popliteus muscle, and occasionally terminates in the capsular
membrane.

The posterior ligament is a flat fasciculus of fibres passing from
behind the inner tuberosity of the tibia upwards and outwards to the
external condyle of the femur, and is in part continuous at its inner end
with the tendon of the semimembranosus muscle.

Fig. 149.

Fig. 149, A.—Ricut Kyzx-Jornt, FROM THE INSIDE AND ANTERIORLY. (A.'T.) 3

1, tendon of the rectus muscle near its insertion into the patella ; 2, insertion of the
vastus internus into the rectus tendon and side of the patella ; 3, ligamentum patelle
descending to the anterior tuberosity of the tibia ; 4, capsular fibres forming a lateral
ligament of the patella prolonged in part from the insertion of the vastus internus down-
wards towards the inner tuberosity of the tibia : 5, internal lateral ligament ; 6, tendon
of the semimembranosus muscle. (After Arnold.)

Fig. 149, B.—Kyux-Jomrt prom Beuinp. (A. T.)

1, insertion of the tendon of adductor magnus; 2, origin of the inner head of the
gastrocnemius muscle ; 3, outer head of the same ; 4, cord-like external lateral ligament ;
5, tendon of the popliteus muscle: a ligament descending from behind the outer condyle
of the femur is seen attached to this tendon below, and another descending from the
tendon is attached to the head of the fibula, constituting the short external lateral liga-
ment ; 6, part of internal lateral ligament ; 7, tendon of the semimembranosus muscle ;
8, posterior ligament of Winslow, spreading outwards from the tendon ; 9, expansion of
the popliteal fascia downwards from the same, represented as cut short ; 10, on the head
of fibula, marks the posterior superior tibio-fibular ligament; 11, upper part of the
interosseous ligament, with the foramen above it for the anterior tibial artery.

The ligamentum patelle is a strong flat tendinous band, attached
superiorly to the lower extremity of the patella, and the depression
beneath its articular surface, and inferiorly to the anterior tubercle of

168 ARTICULATIONS OF THE LOWER LIMB.

the tibia. Between the tibia and the ligament, near its insertion, is
placed a synovial bursa. If the patella be considered a sesamoid bone,
this ligament may be regarded as part of the tendon of the rectus
femoris muscle.

The crucial ligaments, placed in the centre of the joint, pass from
the sides of the intercondylar fossa to the spaces in front of and
behind the spine of the tibia. They decussate somewhat like the lines
of the letter X. The anterior or external ligament is fixed by its lower

Fig. 150.

Fig, 150, A—Tur Kyex-Jornt, OPENED FROM BEFORE, TO sHOW THE CrucIAL Liga-
MENTS AND SummunaR Carriages. (A. 7.) 2

1, external, and 2, internal semilunar cartilage; 3, on the outer condylar surface of
the femur, points to the anterior crucial ligament ; 4, placed on the elevated line separat-
ing the patellar from the inner condylar surface of the femur, points to the posterior
crucial ligament ; 5, transverse ligament of the semilunar cartilages ; 6, part of the
ligamentum patelle ; 7, on the head of the fibula, points to the superior anterior tibio-
fibular ligament ; 8, upper part of the interosseous membrane, showing the perforation

for the anterior tibial artery.

Fig. 150, B.—Tur Knen-Jornt, opRNED FROM BEHIND, SO AS TO EXPOSE THE CRUCIAL
LicgaMENTS AND Seminunar Cartinacres. (A. T.) 4

1, internal semilunar cartilage ; 2, external semilunar cartilage; 3, anterior crucial
ligament ; 4, posterior crucial ligament : farther up is seen its accessory band joining the
external semilunar cartilage ; 8, upper part of the interosseous membrane ; 9, internal
lateral ligament ; 10, placed on the head of the fibula, points to the posterior superior
tibio-fibular ligament ; between the head of the fibula and the external semilunar cartilage
(2) is seen the synovial surface of the tibia, upon which the semilunar cartilage descends
in flexion, and where a communication sometimes takes place between the synovial
cavities of the knee-joint and the tibio-fibular articulation.

extremity to the inner part of the pit before the spine of the tibia, and
by its upper extremity it is inserted into the inner and hinder part of
the external condyle of the femur; hence its direction is upwards,
backwards, and outwards. The postericr or internal ligament is at-

INTERIOR OF THE KNEE-JOINT. 169

tached inferiorly to the back of the pit behind the tibial spine, and
superiorly to_the fore part of the intercondylar hollow, as well as
slightly to the side of the inner condyle of the femur; its fibres are
directed upwards and a little forwards.

Thesemilunar cartilages aretwo crescent-shaped interarticular fibro-
cartilages, placed on the articulating surfaces of the head of the tibia,
and interposed between these and the condyles of the femur. They
have each a synovial surface above and below, and a convex border,
which is thick, while the concave border is thinned to a fine edge, and
the part of the articular surface of the tibia within the concave border
of each cartilage is left uncovered. At their extremities they are
fibrous, and are firmly fixed to the head of the tibia, whilst by the cir-
cumference they are connected with the fibrous capsule of the joint.

Fig. 151.—Vinw oF tHE INTERARTICULAR FrpRo- Fig. 151.
CARTILAGES OF THE RIGHT KNEE-JoINT, FROM
ABOVE, WITH THE CrucrtAn LigAMENTS DIVIDED,
AND THE LIGAMENTUM PATELLE TURNED FOR-
warps. (A.T). 4

1, ligamentum patelle ; 2, the inner fibro-
cartilage; 3, the outer one ; 4, the anterior tuber- hh
osity of the tibia in front of the transverse liga-
ment ; 5, the cut end of the anterior crucial liga- ;
ment directed obliquely towards the outer side and
backwards ; 6, the cut end of the posterior crucial 6 68
ligament, from which fibres are seen descending to
the outer fibro-cartilage ; 6’, tibial attachment of the posterior crucial ligament ; 7, the
head of the fibula; 8, the synovial surface of the tibia, which extends for some way
downwards towards the tibio-fibular synovial sac, with which it is sometimes continuous.

The internal semilunar cartilage forms nearly a semicircle ;
its anterior cornu is small and pointed, and is inserted into an impres-
sion at the fore and outer part of the internal articular surface of the
tibia ; its posterior end is attached to the inner edge of the hollow
behind the spine, and is in relation with the posterior crucial liga-
ment.

The external semilunar cartilage forms more than three-fourths of
a circle ; its two cornua, fixed, one before, the other between the points of
the spine of the tibia, are so close at their insertion that they may be said
to be interposed between the attachments of the internal semilunar
plate. Its external border is in contact behind with the tendon of the
popliteus muscle, and is therefore separated by this from the fibrous
capsule. From this fibro-cartilage a ligamentous band ascends, to be
attached to the inner condyle of the femur in connection either in front
or behind with the posterior crucial ligament (accessory band of the
posterior crucial ligament).

Transverse ligament.—Towards the front of the joint the convex
borders of the interarticular fibro-cartilages are connected by a slight
transverse band, which receives this name. Its thickness varies much
in different bodies.

Capsular membrane.—Under this name is described the fibrous
tissue which invests the joint in the intervals between the stronger
bands which have been named ligaments. It is incomplete, not extend-
ing underneath the tendons of the extensor muscles. Between the sides

170 ARTICULATIONS OF THE LOWER LIMB.

of the patella and the femur it consists of fibres connected with the
insertion of the vasti muscles and with the fascia lata, and thus forms
the structures, uniting the patella to the tibia, which have been called
lateral patellar ligaments ; posteriorly it covers the condyles of the
femur beneath the gastrocnemius muscle. In this last situation it is
thin, and a sesamoid bone is often found in connection with it in the
outer, less frequently in the inner head of the muscle.

The synovial membrane is the largest in the body. Traced down-
wards from the femur on either side of the joint, it may be followed
from the capsule to the upper surface of the semilunar cartilages, round
the free borders of those structures to their inferior surfaces, and thence
to the tibia. The crucial ligaments are invested in front by a reflected

Fig. 152.—Verrican Anrmro-Postrrior Section
oF THE Lerr KNEE-JornT, SEEN FROM THE

OUTER OR LEFT sipE. (A. 7.) 4

The section is made somewhat obliquely a little
to the outside of the middle, so as to preserve entire
the crucial ligaments with their attachments : it is
from a young subject of eighteen or nineteen years.
1, 1, the upper portion of the synovial cavity ex-
tending upwards between the extensor tendons and
the femur ; 1’, an aperture made into the posterior
portion of the synovial cavity ; 2, 2’, ligamentum
mucosum ; 3, ligamentum patelle ; 2’, 3, the sub-
patellar synovial fatty cushion ; 4, bursa above the
insertion of the ligamentum patelle into the ante-
rior tibial tuberosity ; 5, 5’, the anterior crucial
Jigament ; 5’, points also to the internal semilunar
cartilage within the joint; 6, lower part of the
posterior crucial ligament, the upper part of which
is towards 2; 6’, the accessory band joining the
external semilunar cartilage, which is cut short ;
7, the spine of the tibia.

portion of the membrane continued for-
wards from the posterior wall of the joint.
Between the tibia and patella the syno-
vial membrane lies upon a large pad or
cushion of fat, on the surface of which
it forms two lateral folds (alar hgaments)
which fit into the space between the
tibia, patella and femur, while from the
middle of the pad it sends backwards
a tapering process, the ligamentum mucosum, through the joint to the
front of the intercondylar fossa. Above the patella the synovial mem-
brane extends upwards some distance, forming a large pouch between
the extensor tendons and the femur.

Movements, &c.—In order to explain the nature of the movements, it is
necessary to state some considerations with regard to the relations of the several
parts of the knee-joint to each other. The knee-joint may be regarded as con-
sisting of three articulations conjoined, viz., that between the patella and femur,
and two others, one between each condyle of the femur and the tibia. In most
mammals the synovial membranes of those three joints are either completely
distinct or communicate with each other by only small openings; and this some-
times occurs in Man, In the human subject the ligamentum mucosum is an

ge

MOVEMENTS OF THE KNEE-JOINT. 171

indication of the original separation of the synovial membranes of the inner and
outer joints, and the crucial ligaments may be looked upon as the external and
internal lateral ligaments of those two joints respectively. Each portion of the
articular surface of the femur belongs either to one or other of the three com-
ponent joints of the knee. and no part is common to any two of them. Ona
well-marked femur, the inferior limits of the patellar surface are quite distin-
guishable; the line which separates this surface from the outer tibial joint
passing directly between it and the condyle, and that which separates it from
the inner joint being continued backwards, so as to cut off from the rest of the
inner condyle a narrow tract at the side of the intercondylar fossa,

Fig, 153.

ty

\

|

;

My

|

it
mn

i

\

\
MI i
iN

———

i }

(Wha
yi

ih
hs Mil

vy, , iy

Fig. 153.—TuHE SUPERFICIAL PARTS OF THE KNEE-JOINT REMOVED, AND THE EXTERNAL
CoNDYLE OF THE Femur SAWN OFF OBLIQUELY, TOGETHER WITH HALF THE PATELLA,

SO AS TO EXPOSE BOTH THE CRUCIAL LIGAMENTS TOGETHER. (A. 7.) 3}

In A, the parts are in the position of extension, in B, that of flexion, the figures being
designed to show the different state of tension of the crucial ligaments in these positions.
1, sawn surface of the femur ; 2, sawn surface of the patella; 3, ligamentum patelle ;
4, anterior or external crucial ligament, tense in A, and relaxed in B; 5, posterior or
internal crucial ligament, relaxed in A, tense in B ; 6, internal, and 7, external semilunar
cartilage ; 8, transverse ligament ; 9, articular surface of the tibia, extending behind the
external semilunar cartilage ; 10, on the head of the fibula, points to the anterior superior

s

tibio-peroneal ligament ; 11, upper part of the interosseous membrane,

The movement of the patella on the femur is one partly of gliding, partly of
coaptation. This is illustrated by a careful examination of the articular surface

_ of the patella, which is not uniformly curved from above downwards, as it would

be, were the movement one of gliding only, but exhibits on each side of the
vertical ridge three very slightly depressed surfaces, separated by two slight
transverse elevations, and along the inner margin a seventh area, upon which
the transverse lines do not encroach (Goodsir.) When the knee is extended, and
the patella drawn upwards by the extensor muscles, the two inferior facets of
the patella are in contact with the upper margin of the femoral surface; in
semiflexion the middle facets only are in contact with the femur; in greater
flexion, the superior parts of the patella are in contact with the lower part of

Ulkombad

172 ARTICULATIONS OF THE LOWER LIMB.

the femoral surface; and in extreme flexion the patella, which has been
gradually turned outwards by the increasing prominence of the inner condyle,
rests by its innermost facet on the outer margin of that condyle. The articula-
tion between each condyle and the opposed almost flat surface of the tibia, while
resembling, is not exactly a hinge joint, and extension and flexion, the move-
ments of which it is capable, are produced by a combination of gliding, rolling,
and rotation. If the condyles of the femur be examined as they rest upon the
tibia in the flexed position of the joint, it will be seen that the inner condyle is
longer than the outer, and that its anterior portion inclines obliquely outwards,
to reach the patellar surface. In the movement of extension the condyles move
parallel to one another, both gliding and rolling until extension is nearly com-
pleted, and then, the anterior part of the rolling surface of the external condyle
having already come into contact with the tibia, the inner condyle continues to
glide backwards, bringing its oblique anterior part into contact with the tibia, so
that the bone is rotated inwards on the tibia, and over-extension is prevented,
not merely by the tightness of the ligaments, but by the femur being pressed up
against the tibial spine. In complete extension the lateral ligaments and the
external crucial ligament are tight, while the posterior crucial ligament is
relaxed ; in flexion, the posterior crucial ligament only is tightened, the others
being relaxed. In extension of the joint no rotation of the leg is possible; in
the flexed condition a considerable amount is allowed. The semilunar cartilages
being loosely attached to the head of the tibia, move forwards in extension and
backwards in flexion of the joint; and further, as the condyles rolling upon the
tibia present to the condylar surfaces of that bone portions haying different
curvatures, each cartilage, ike a moveable wedge, is contracted round the con-

. dyle during flexion of the joint and teased during extension. In extension of

the knee, as the weight of the body keeps the bones in their position, the extensor
muscles are relaxed, the patella drops down from its position in contact with the
femur, and the ligamentum mucosum then comes into play, supporting the
synovial membrane and fat below the patella. As the line of the centre of
gravity of the body in the erect attitude descends in front of the axis of motion
of the knee-joint, there is a tendency to over extension of the joint, which is
resisted by the tension of the two lateral and the posterior ligaments, as well as
of the anterior crucial, and thus the maintenance of the erect attitude without
muscular effort is partly due to the mechanism of the knee-joint. (See Meyer,
op. cit.; Goodsir, “‘ Anatomical Memoirs,” vol. ii. pp. 220, 231 ; Langer, ‘“ Sitz-
ungsber d. Acad. der Wissensch. Wien,’ 1858 ; Henke, “ Zeitschr. fiir rat. Med.,”
Vv. Vili., 1859.)

TIBIO-FIBULAR ARTICULATIONS.

The tibia and fibula are connected at their upper and lower extremities
by synovial articulations, and their shafts are united by an interosseous
membrane. :

Upper tibio-fibular articulation.—The superior extremities of the
bones present two flat oval articular surfaces, retained in close contact
by an anterior and a posterior superior tibio-fibular ligament, both of
which pass upwards and inwards from the head of the fibula to the
external tuberosity of the tibia. The synovial membrane which lines
this joint not unfrequently communicates posteriorly with that of the
knee.

The interosseous membrane or ligament, which connects the
shafts of the tibia and fibula, passes between the external ridge of the
tibia and the ridge on the inner surface of the fibula, and is composed
for the most part of parallel fibres running outwards and downwards,
only a few fibres crossing them in a different direction. ‘The membrane
is broader above than below, and presents superiorly an elongated
opening for the transmission of the anterior tibial vessels, and inferiorly

THE ANKLE-JOINT. 17s

a small aperture for the passage of the anterior branches of the peroneal
vessels.

Fig. 154.—Arrrovnatioys or THE Kner, Lea And ANKLE, SEEN

FROM BEFORE. +

i superior anterior tibio-fibular ligament ; 2, interosseous mem-
brane ; ; 3, the anterior inferior tibio-fibular ligament ; 4, internal
lateral ligament of the ankle-joint ; 5, middle vertical part (cal-
caneo- -fibular) of the external lateral ligament of the ankle-joint ;
6, anterior part (talo-fibular) of the same; 7, anterior ligament of

the ankle-joint.

Lower tibio-fibular articulation.—The inferior
extremities of the tibia and fibula are in contact by
surfaces which for the most part are rough and bound
together by ligament, but near their lower edges are
smooth and covered by cartilage. The tibial sur-
face is concave, the fibular convex ; but the lower

edges of both surfaces are straight. The strong short

fibres which pass directly betiveen the opposed sur-
faces form the m/ferior interosseous ligament. ‘The
anterior ligament is a flat band of fibres, extended
obliquely over the lower part of the bones, the
direction of its fibres being downwards from the
tibia to the fibula. The posterior ligament, some-
what triangular, is similarly disposed behind the
articulation ; its outer surface is covered by the
peronei muscles. The transverse ligament, longer
and narrower than the preceding, is placed imme-
diately below it ; its fibres are horizontal, and extend
from the external malleolus to the contiguous part
and hinder border of the articular surface of the tibia;
it closes the interval between the bones.

The synovial cavity lying between the small articu-
lar surfaces is an extension of that of the ankle-joint.

THE ANKLE-JOINT.
In this articulation, which is a hinge joint, the inferior extremi-

Fig. 155.—Tar Lower Treto-Finutar ArticuLATION AND Fig. 155.
ANKLE-JOINT, FROM BEHIND.

1, inferior posterior tibio-fibular ligament ; 2, transverse
ligament ; 3, posterior fibres of the internal lateral ligament
of the ankle-joint ; 4, middle, and 5, posterior part of the
external lateral ligament of the ankle-joint ; 6, posterior
talo-calcaneal ligament.

ties of the tibia and fibula are united so as to

present a three-sided hollow, which embraces

the astragalus, and renders lateral movement

impossible when the ligaments are tense. 3
The internal lateral or deltoid ligament

is a flat fasciculus of fibres, much broader at

the lower than at the upper part. One ex-

tremity is attached to the groove on the inferior border of the internal

174 ARTICULATIONS OF THE LOWER LIMB.

malleolus ; the other, to the inner side of the astragalus, the os calcis,
and the scaphoid bone, as well as to the inferior calcaneo-scaphoid liga-
ment.

The external lateral ligament consists of three distinct bands
separated by intervals and disposed in different directions. 1. The
middle band descends from the extremity of the fibula, and is inserted
into the middle of the external surface of the os calcis. 2. The
anterior band passes obliquely forwards and inwards from the fore
part of the outer malleolus to a part of the astragalus in front of its
external malleolar surface; it 1s the shortest of the three. 38. The
posterior band, the strongest of the three, passes almost horizontally
inwards from the pit on the inner and back part of the malleolus to the
posterior surface of the astragalus.

Fig. 156.—TRANSvERSE-VERTICAL SECTION OF THE Rigut
ANKLE-JOINT NEAR ITS MIDDLE, AND OF THE PosTERIOR
Tato-CALCANEAL ARTICULATION, SO AS TO SHOW THE
SHAPE OF THE ARTICULAR SuRFACHS AND CAVITIES,
VIEWED FROM BEFORE. (A. 1.) 4

1, internal, 2, external malleolus ; 3, placed on the astra-
galus at the angle between its superior and its external
malleolar surfaces ; 4, interosseous tibio-fibular ligament ;
5, internal lateral ligament of the ankle-joint ; 6, susten-
taculum tali; 7, calcaneo-fibular or middle part of the
external lateral ligament; 8, inner part of the interosseous
calcaneo-talar ligament; 9, great tuberosity of the cal-
caneum : between the tibia, fibula and astragalus, the
synovial cavity is indicated by the dark space enclosed by a
white line ; between the astragalus and os calcis a section
of the posterior calcaneo-talar synovial cavity is shown.

The anterior and posterior ligaments are
merely scattered fibres in front of and behind
the joint ; those of the posterior ligament are weak and principally
transverse.

The synovial membrane of the ankle-joint extends upwards by a
small process which lines the inferior peroneo-tibial articulation.

Movements.—The movements of the ankle-joint are mainly those of flexion
and extension of the foot, the directions of those movements being principally
determined by the shape of the articular surfaces. The external border of the
superior cartilaginous surface of the astragalus is curved, and longer than the
internal border, and hence extension of the ankle-joint is accompanied with a
slight inward movement of the toes. The horizontal surfaces of both the tibia
and astragalus are broader in front than behind ; hence in complete extension of
the ankle the narrow part of the astragalus is brought into the widest part of -
the space between the malleoli, and a certain amount of lateral motion is allowed,
whereas in complete flexion, as when the weight of the body, with completely
bended knees, is supported on the toes, the broad part of the surface of the
astragalus is pushed back into the narrowest part of the space, and the inferior
extremity of the fibula is pressed upon, so as to stretch the ligaments between it
and the tibia, and thus to prevent lateral movement of the joint, and give it at
the same time a certain amount of spring. There appears to be no other move-
ment between the tibia and fibula; these bones being bound together at their
lower ends with remarkable firmness,

ARTICULATIONS OF THE FOOT.
ARTICULATIONS OF THE CALCANEUM, ASTRAGALUS, AND SCAPHOID

TARSAL ARTICULATIONS 175

BoNES ONE WITH ANOTHER.—The astragalus is connected with the
calcaneum by two synovial articulations, viz., by a posterior one pecu-
liar to those two bones, and by an anterior one common to them with
the scaphoid bone. The following are the principal parts requiring
description. ;

Astragalo-calcaneal ligaments.—The interosseous ligament, broad
and strong, passes vertically downwards from the groove between the
anterior and posterior articular surfaces of the astragalus to the similar
groove between the corresponding articular surfaces of the calcaneum.
A membranous posterior ligament connects the posterior border of the
astragalus with the upper surface of the calcaneum ; its fibres are
oblique and very short. There is also an external ligament, consisting
of a slight fasciculus of fibres, which descends perpendicularly from the
outer surface of the astragalus to the outer side of the calcaneum,
parallel with the middle division of the external lateral ligament of the
ankle-joint. It may be further observed, that those portions of the

Awad lateral ligaments of the ankle-joint which pass down over the astragalus
to the os calcis assist in uniting these two bones.

Fig. 157.—Licaments or THE Foot, sEEN FROM Fig. 157.
BELOW. (A.T.) § :

1 and 2, portions of the internal lateral ligament
of the ankle-joint ; 3, calcaneo-cuboid or long plantar
ligament ; 3’, deep or short part of the same; 4,
plantar caleaneo-scaphoid ligament ; 5, three scaphoido-
cuneiform ligaments of the internal, middle and ex-
ternal cuneiform bones; 6, is placed upon the external
cuneiform bone, towards which is seen coming from
behind a cuboido-cuneiform ligament; 7, is placed
upon the internal cuneiform bone ; from 6 and 7, are
seen passing downwards the plantar-cunco-metatarsal
ligaments ; x, part of the first dorsal cuneo-metatarsal
ligament ; 8 and 9, ligamentous fibres prolonged from
the cuboid bone and sheath of the peroneus Jongus
muscle upon the outer metatarsal bones ; 10, 10, be-
tween these figures the posterier intermetatarsal (or
transverse) ligaments; 11, 11, anterior transverse
metatarsal ligament, continued across the four meta-
tarsal spaces ; 12, intersesamoid ligament; 13, 13,
between these figures are seen the five pairs of internal
and external lateral metatarso-digital ligaments ; 14,
14, between these figures are seen the five pairs of
internal and external lateral digital (phalangeal) liga-
ments of the first series ; those of the second series
have no figure placed to mark them ; 15, inferior liga-
ment of the phalangeal articulation of the great toe.

Calcaneo-scaphoid ligaments. — The
calcaneum and scaphoid bone are not in
contact, but they are connected by two
ligaments. The inferior or plantar liga-
ment, much the larger of the two, is a broad band which passes for-
wards and inwards from the fore part of the calecaneum (susten-
taculum tali) to the inferior surface of the scaphoid bone. It is in
contact inferiorly with the tendon of the tibialis posticus muscle, while
superiorly it forms the floor of the articular cavity which receives
the head of the astragalus, and is lined by synovial membrane. The
external, dorsal, or interosseous ligament, forms the external boundary

176 ARTICULATIONS OF THE LOWER LIMB.

of the cavity just mentioned, and lies deeply at the anterior part of the
fossa (sinus pedis), between the astragalus and os calcis. Its fibres,
very short, are directed from behind forwards between the contiguous
extremities of the bones. They are attached posteriorly to a ridge of the
os calcis that separates the articular surfaces for the astragalus and os
cuboides, and anteriorly to the outer side of the scaphoid bone.

The talo-scaphoid or astragale-scaphoid ligament, a membranous
hand of fibres situated on the dorsum of the foot, extends obliquely
forwards from the anterior extremity of the astragalus to the superior
surface of the scaphoid bone, and completes the capsule of the calcaneo-
talo-scaphoid joint, formed in the rest of its extent by the plantar and
external calcaneo-scaphoid ligaments.

Two synovial membranes line the articulations of the caleaneum
and scaphoid with the astragalus, one belonging to the calcaneo-talar
joint, and another to the caleaneo-talo-scaphoid articulation.

CancANno-Cusord ArticuLATION.—The calcaneum is united to the
cuboid bone by a synovial joint and ligaments.

The inferior ligament consists of two distinct fasciculi of fibres, of
which one is superficial, the other deep-seated. ‘The superficial parts
called the long plantar ligament, is the longest of the tarsal liga-
ments. Its fibres, attached behind to the inferior surface of the calca-
neum as far as the anterior tubercle, pass forwards, and are attached in
creater part to the tuberosity on the under surface of the cuboid bone ;
some of them are continued onwards, and terminate at the bases of the

Fig. 158.

Fig. 158.—Licaments oF THE Foot, From THE INNER SIDE. (A. T.) 2

1, internal lateral ligament of the ankle; x, in front of the sustentaculum tali, show-
ing part of the internal lateral ligament descending upon it ; 2, posterior talo-calcaneal
ligament ;~-3;-posterior ligament of the ankle-joint ; 4, part of the long and short calca-
neo-cuboid ligaments seen from the inside ; 5, two superior astragalo-scaphoid or talo-
scaphoid ligaments ; 6, internal talo-scaphoid ligaments ; 7, internal scaphoido-cuneiform
(first) ; 8, dorsal or superior cuneiform ; 9, scaphoido-cuneiform (second) ; 10, inter-
cuneiform, or transverse dorsal cuneiform, between the first and second cuneiform bones ;
11, internal or first tarso-metatarsal ligament ; 12, inferior first tarso-metatarsal ; 13, in-
ternal lateral metatarso-phalangeal ; the internal sesamoid bone is seen below; 14,
internal lateral interphalangeal ligament of the first toe.

TARSAL ARTICULATIONS. 177

third and fourth metatarsal bones, after covering the tendon of the
peroneus longus muscle. The short or deep-seated plantar liga
ment lies close to the bones, being separated from the superficial part
by some cellular tissue. Its breadth is considerable, its length scarcely
an inch. One extremity is attached to the calcaneum in front of the
long ligament, the other, somewhat expanded, to the under surface of
the cuboid bone, internal to the tuberosity.

The dorsal or superior ligament is a flat band of fibres which
connects the anterior and upper surface of the calcaneum with the
adjacent part of the cuboid bone.

The internal or interosseous ligament is placed deeply in the
hollow between the astragalus and os calcis, and is closely connected
with the external calcaneo-scaphoid ligament.

A separate synovial membrane lines this joint.

ARTICULATIONS OF THE SCAPHOID, CUBOID, AND CUNEIFORM BONES,
ONE WITH ANOTHER.—Scapho-Cuboid Articulation.—The scaphoil
and cuboid bones are connected by a dorsal ligament, composed of short

Fig. 159.

Fig. 159.—LicAMENTS OF THE Foot, FROM THE OUTSIDE AND DorsAL aspEct. (A.T.) 3

1, lower part of the interosseous membrane ; 2, lower anterior tibio-peroneal ligament ;
3, lower posterior tibio-peroneal ligament ; 4, middle part of the external lateral ligament
of the ankle-joint, passing to the caleaneum ; 5, anterior part of the external lateral
ligament of the ankle-joimt, passing to the astragalus; below the last ligament the
external calcaneo-talar ligament has not been represented in this figure ; 6, posterior part
of the external lateral ligament of the ankle-joint, passing to the astragalus ; 7, is placed
above the interosseous calcaneo-talar ligament ; 8, dorsal calcaneo-scaphoid ; 9, dorsal
calcaneo-cuboid ; 10, part of the long plantar or calcaneo-cuboid ; 11, superior talo-sca-
phoid ; 12 and 13, second and third scapho-cuneiform, and between them one of the
intercuneiform ligaments ; 14, superior scapho-cuboid; 15, placed on the external
cuneiform bone, points to the cuneo-metatarsal ligaments from that bone to the second,
third, and fourth metatarsal bones ; 16, cuneo-metatarsal ligament, from the first cunei-
form to the second metatarsal bone ; between 12 and 16, are seen the cuneo-metatarsal
ligaments which converge from the three cuneiform bones on the second metatarsal ; 17,
cubo-metatarsal ligament passing to the fourth metatarsal bone ; 18, that to the fifth,
19 and x x, dorsal intermetatarsal ligaments; 20, lateral metatarso-digital ; 21, 22,
lateral digital.

VOL. I. N

178 ARTICULATIONS OF THE LOWER LIMB.

thin fibres, extending obliquely between the two bones ; a plantar, con-
sisting of transverse fibres ; and an @terosseous ligament, which inter-
venes between their contiguous surfaces. When the bones touch, which
is not always the case, they present two small articulating surfaces,
which are covered with cartilage and have between them an offset of
the adjacent synovial membrane.

Scaphe-Cuneiform Articulation.—The scaphoid and the cuneiform
bones are held together by dorsal ligaments. It will be recollected that
ihe scaphoid articulates with the three cuneiform bones by the smooth
faces on its anterior surface. The dorsal ligaments, three in number,
pass from the upper surface of the scaphoid to the first, second, and
third cuneiform bones, into which they are respectively inserted.
Plantar bands are similarly disposed on the under surface of the bones,
but these are continuous with, or offsets from, the tendon of the
tibialis posticus muscle.

Cubo-cuneciform Articulation.—The cuboid and the external cuneiform
hones are connected by a dorsal ligament, which is a thin fasciculus of
transverse fibres ; a planiar ligament, whose fibres are also transverse
and rather indistinct ; and a bundle of dnterosseous fibres. Between

Fig. 160.

Fig. 160.—Tar Synovian CAvities OF THE ANKLE-JOINT AND THE TARSAL AND
Tarso-MrrararsAL ARTICULATIONS, IN Section. (A. T.) 43

The section has been carried obliquely upwards and inwards across the foot, and
vertically through the upper part of the astragalus and the tibia. 1, cut surface of the
tibia above the ankle-joint ; 2, placed on the astragalus above the posterior calcaneo-talar
synovial cavity ; 8, on the head of the astragalus close to the common calcaneo-talo-
scaphoid synovial cavity ; 4, interosseous calcaneo-talar ligament ; 5, on the anterior edge
of the caleaneam, points to the calcaneo-cuboid synovial cavity ; 6, interosseous calcaneo-
cuboid ligament ; 7, on the scaphoid bone, marks the common scapho-cuneiform and
intercuneiform synovial cavity ; 8, on the cuboid bone, points to the interosseous
scapho-cuboid ligament ; 9, internal, 10, middle, 11, external cuneiform bones ; 12,
eaboid : between these several bones the interosseous ligaments are shown ; from 13 to 17,
are the metatarsal bones, with the interosseous ligaments between them ; between 9 and
14, the interosseous ligament from the internal cuneiform to the second metatarsal bone ;
11 and 16, the interosseous ligament from the external cuneiform to the fourth metatarsal
bone : there are also shown in this figure, the synovial cavity of the first tarso-metatarsal
articulation, that between the middle and external cuneiform bones and the second and
third metatarsal ; and that between the cuboid and the fourth and fifth metatarsal bames.

TARSO-METATARSAL ARTICULATIONS. 179

the two bones a distinct articulation is formed by cartilaginous sur-
faces ; it is provided sometimes with a separate synovial membrane, at
others with an offset from that which belongs to the scapho-cuneiform
articulation.

The three cuneiform bones are connected by transverse dorsal liya-
ments and strong dnterosseous fibres ; the latter being their most efficient
uniting structures. A transverse plantar ligament exists only between
the two innermost bones. The articulations between these bones are
lined by offsets from the synovial membrane of the joint between them
and the scaphoid bone.

ARTICULATION OF THE TARSUS WITH THE METATARSUS.—The four
anterior bones of the tarsus, viz., the three cuneiform and the cuboid,
articulate with the metatarsal bones ; and as the first and third cunei-
form bones project beyond the middle one, and the third cuneiform
beyond the cuboid bone, the anterior surface of the tarsus is very
irregular. The first metatarsal bone articulates with the internal
cuneiform ; the second is wedged in between the first and third cunei-
form, and rests against the second ; the third metatarsal bone articu-
lates with the extremity of the external cuneiform ; and the last two
with the cuboid bone, the fourth having also an attachment to the
external cuneiform. The articulations are furnished with synovial mem-
branes, and the bones are held in contact by dorsal, plantar, and in-
terosseous ligaments.

The dorsal tarso-metatarsal ligaments are flat thin bands of parallel
fibres, which pass from behind forwards, connecting the contiguous
extremities of the bones before mentioned. Thus the first metatarsal
bone receives a broad thin band from the corresponding cuneiform
bone; the second receives three, which converge to its upper surface,
one passing from each cuneiform bone; the third has one from the
external cuneiform bone; and, finally, the last two are bound by a

fasciculus from each to the cuboid bone, and by fibres to the external

cuneiform from the fourth metatarsal bone. The plantar ligaments are

less regular ; the bands of the first and second toes are more strongly

marked than the corresponding ligaments on the dorsal surface ; and
those of the fourth and fifth toes, which are merely a few scattered
fibres passing to the cuboid, receive support from the sheath of the
peroneus longus muscle. Ligamentous bands stretch in an oblique or
transverse direction from the internal cuneiform to the second and
third metatarsal bones, and from the external cuneiform to the fifth
metatarsal.

The interosseous ligaments run obliquely between the bones, and
from their strength and deep position oppose great resistance to the
knife in separating the metatarsus from the tarsus. a. The internal
and largest of these extends from the outer side of the first cunei-
form bone, to the neighbouring side of the second metatarsal, close
to the articular surface. 6. The external interosseous ligament sepa-
rates the articulation of the fourth and fifth metatarsal bones from
the rest. {t cornects the outer side of the external cuneiform bone
to the same side of the third, and very strongly to the inner side
of the fourth metatarsal. c. Occasionally some fibres, of less strength
and importance than the preceding, are observable on the outer
side of the second metatarsal bone, connecting it to the middle
cuneiform,

N2

180 ARTICULATIONS OF THE LOWER LIMB.

The interosseous ligaments are found to vary somewhat in their connections
from those here stated, being sometimes attached at once to the contiguous
sides of two tarsal and two metatarsal bones. Attention was first particularly
directed to these ligaments by M. Lisfranc, in connection with the amputation
of the foot through the tarso-metatarsal articulation. See ‘* Manuel des Opéra-
tions Chirurgicales,” &c. Par J. Coster. 3rd edit. Paris, 1829.

Synovial membranes.—There are three synovial membranes in this
irregular series of articulations. a. One belongs to the internal cunei-
form and the first metatarsal bone: the joint formed between these two
bones is altogether separate and out of the range of the rest. 0. A
second synovial membrane is placed between the cuboid and the fourth
and fifth metatarsal bones; this is isolated on the inner side by the
external interosseous ligament. c. The third or middle one is placed
between the middle and external cuneiform and the second and third
metatarsal bones, and is prolonged between the two last-named bones,
as well as sometimes between the third and fourth metatarsal bones.
The disposition of this last synovial membrane is subject to variation.

Metatarsal Articulations.—The metatarsal bones are bound
together at their tarsal and digital ends ; very firmly in the former, and
loosely in the latter situation.

The tarsal ends of the four outer bones articulate with each other, hay-
ing lateral cartilaginous surfaces and provided with synovial membrane,
and are connected by dorsal, plantar, and interosseous ligaments. The

Fig. 161.

Fig. 161.— Vertican Antero-Posterior Section or THE ANKLE-JoInT AND ARTIOW-
LATIONS OF THE Foor, A LivTLE To THE IysipE oF THE MippLE OF THE GREAT ToE

or THE Ricut Foor. (A. T.) 2

1, the synovial cavity of the ankle-joint ; 2, the posterior talo-calcaneal articulation ;
3, placed above the talo-scaphoid articulation ; 3’, on the astragalus above the anterior
talo-calcaneal articulation, which is continuous with the preceding : the interosseous liga-
ment is seen separating 2 from 3’; 4, the inferior calcaneo-scaphoid ligament ; 5, part of
the calcaneo-cuboid or long plantar ligament ; 6, the scapho-cuneiform articulation ; 7,
the first cuneo-metatarsal articulation ; 8, the first metatarso-phalangeal articulation ;
9, section of the inner sesamoid bone ; 10, the phalangeal articulation ; 11, placed on the
calcaneum, indicates the bursa between the upper part of the tuberosity of that bone and
the tendo Achillis.

METATARSAL AND DIGITAL ARTICULATIONS. 181

dorsal and plantar ligaments are short transverse bands stretching
across the five metatarsal bones from one to another. The ¢nterosseous
fibres, lying deeply between the bones, occupy the rough parts of their
lateral surfaces : they are of considerable strength and firmness. The
intermetatarsal articular cavities are lined with synovial membrane,
which in each is continued forwards from that lining the joints formed
between the bases of these bones and the tarsus. The first and second
metatarsal bones do not articulate laterally with each other.

Transverse metatarsal ligament.— The digital extremities or heads
of the metatarsal bones are loosely connected by a transverse band, which
is identical in its arrangement with the corresponding structure in
the hand, with this exception, that it is attached to the great toe,
whereas in the hand the transverse metatarsal ligament does not reach
the thumb.

Fig. 162.—LicaAmMEents oF THE Foot, sEEN FROM
BELOW. (A.T.) 43

1 and 2, portions of the internal lateral ligament
of the ankle-joint ; 3, caleaneo-cuboid or long plantar
ligament; 3’, deep or short part of the same; 4,
plantar calcaneo-scaphoid ligament; 5, three scapho-
cuneiform ligaments of the internal, middle and ex-
ternal cuneiform bones ; 6, is placed upon the external
cuneiform bone, towards which is seen coming from
behind a cubo-cuneiform ligament; 7, is placed
upon the internal cuneiform bone ; from 6 and 7, are
seen passing downwards the plantar cuneo-metatarsal
ligaments ; x , part of the first dorsal cuneo-metatarsal
ligament ; 8 and 9, ligamentous fibres prolonged from
the cuboid bone and sheath of the peroneus longus
muscle upon the outer metatarsal bones ; 10, 10, be-
tween these figures, the posterior intermetatarsal (or
transverse) ligaments; 11, 11, anterior transverse
metatarsal ligament, continued across the four meta-
tarsal spaces; 12, intersesamoid ligament; 13, 13,
between these figures are seen the five pairs of internal
and external lateral metatarso-digital ligaments ; 14,
14, between these figures are seen the five pairs of
internal and external lateral digital (phalangeal) liga- 13-BX
ments of the first series ; those of the second series
have no figure placed to mark them ; 15, inferior liga-
ment of the phalangeal articulation of the great toe. f

RPARLENGERL 7 {i

METATARSO-DIGITAL AND INTERSEOELAL

ARTICULATIONS.—The heads of the meta-
tarsal bones are connected with the small =
concave articular surfaces of the first phalanges by two lateral ligaments,
an inferior ligament, to which sesamoid plates are united by scattered
fibres, and a synovial membrane,—all which are closely similar to those
which belong to the corresponding parts of the hand. In the first
metatarso-digital articulation the sesamoid plate is divided into two
parts, which are fully ossified, forming the sesamoid bones. These aré
held together by strong transverse ligamentous fibres, and being provided
with cartilaginous surfaces, move upon the corresponding grooved
cartilaginous surfaces of the first metatarsal bone.

The articulations of the phalanges with one another are also con.
structed on the same plan as those of the superior extremity. In each,
the bones are held in contact by two lateral ligaments and an inferior

182 ARTICULATIONS OF THE LOWER LIMB.

ligament or fibrous plate ; and each of the cavities is lined by a synovial
membrane.

Movements.—In the mechanism of the foot three arches are distinguishable,
two of them longitudinal and one transverse ; all of them capable of being
flattened somewhat by pressure from above, thus securing elasticity. The inner
arch is formed by the os calcis, astragalus, scaphoid, and three cuneiform bones,
together with the three inner toes, the head of the astragalus being the key-
stone, and is supported by the inferior calcaneo-scaphoid ligament. The outer
arch is formed by the os calcis, cuboid bone, and two outer toes, and is supported
by the strong inferior caleaneo-cuboid ligaments. Thus the calcaneo-scaphoid
and calcaneo-cuboid ligaments are stretched by the whole weight of the body
bearing down upon the arch, and prevent the too great flattening of the instep ;
an action in which they are assisted, however, by the plantar aponeurosis. The
transverse arching of the foot is most marked in the line of the tarso-metatarsal
articulations, and is maintained by the wedge-shape of the bones and by the
plantar ligaments. The weight of the body, falling upon the balls of the toes
when the heel is raised, tends to spread out the metatarsal bones at their distal
extremities, and to flatten the transverse arch, which recovers its position when
the pressure is removed. Between the astragalus and the calcaneum only one
kind of motion is possible, the centre of which is the interosseous astragalo-
caleaneal ligament, and is of such a nature, that when the posterior part of the
os calcis slides inwards and upwards beneath the astragalus, its cuboid extremity
moves downwards and outwards. A certain amount of gliding movement is also
allowed between the tarsal and metatarsal bones, and that most considerably
between the cuboid bone and outer toes. Thus it happens that if the foot is
bent up against the leg, and then is gradually extended by force applied to the
toes, as by the action of the flexores digitorum muscles, the first part of the
movement is accomplished at the ankle, and consists of extension, with only a
slight inward turning of the toes ; further extension is accomplished by moye-
ment between the caleaneum and astragalus, and is accompanied by depression
of the outer edge of the foot; and after that a little more extension, accom-
panied by more considerable depression of the outer edge of the foot, is effected
at the tarso-metatarsal articulations. The direction of the movement of exten-
sion of the toes at the metatarso-phalangeal articulations is upwards and out-
wards, so that although the great toe is in a line with the inner edge of the
foot when resting on the ground, it is no longer so when over-extended.

THE MUSCLES IN GENERAL, 183

Section IIJ.—MYOLOGY.

THE MUSCLES IN GENERAL,

Unver this section will be brought the description of the Voluntary
Muscles, and along with it that of the Fascie and Aponeuroses by
which they are invested.

The voluntary muscles are for the most part placed in close relation
with the Endo-skeleton, being attached to the bones or other hard parts,
and moving these in different directions by their contractions. ‘lhere
are, however, some muscles which may be looked upon as belonging to
the cutaneous system, or Exo-skeleton, and there are a few others which
are connected with the viscera at the places where parts of these reach
the surface of the body. The muscles are all symmetrical, and,
with the exception of the sphincters and one or two others, are in pairs.

The number of voluntary muscles to which distinct names have been
given in the systems of Albinus and Scemmering, which are mainly fol-
lowed in this work, amounts to about 240, there being some variation
above or below that number according as certain muscular parts are
regarded as separate and independent muscles or only as portions of
others. They naturally fall under the following four great divisions,
and in the numerical proportions stated under each, viz. :—

A. In the axial part of the body.

1. The muscles of the head and neck = 75.
2. The muscles of the vertebral column and trunk = 51.

B. In the limbs.

- 8. The muscles of the upper limb = 58.

4, The muscles of the lower limb = 59.

In the detailed description of the muscles, however, while the fore-
going general divisions will be followed, it may be expedient occasion-
ally to deviate from the strictly systematic arrangement, in so far as
may conduce to facility in study and convenience in dissection.

Each muscle constitutes a separate organ, composed chiefly of
a mass of the contractile fibrous tissue which is called muscular,
and of other tissues and parts which may be regarded as accessory.
Thus the muscular fibres are connected together in bundles or fasciculi
(see General Anatomy), and these fasciculi are again embedded in and
united together by a quantity of connective tissue, forming the perimy-
sium, and the whole muscle is usually enclosed in an external sheath of
the same material. Many of the muscles are connected at their more
or less tapering extremities with tendons by which they are attached to
the bones or hard parts ; and tendinous bands frequently run to a con-
siderable length either on the surface of a muscle or between its fibres.
There is indeed great variety in the relation of the muscular and
tendinous portions, but few muscles are entirely destitute of some
tendinous element in their composition.

Further, blood-vessels are largely distributed in the substance of a
muscle, carrying the materials necessary for its nourishment and chemico-
vital changes, and there are also lymphatic vessels, as in other vascular
parts of the body. Nerves are ramified through every muscle, by which
the muscular contractions are called forth and a low degree of sensi-
bility is conferred upon the muscular substance.

The muscles vary much in their individual forms. Some are broad and

184 THE MUSCLES IN GENERAL.

thin, others are more or less elongated straps, and others are cylindrical
or fusiform masses of various thickness; hence some of the various
names applied to them, such as long and short, square, round, rhomboid,
&e. Not unfrequently two or more muscular parts run into one, as in
the bicipital, tricipital, or quadricipital forms. In other instances
muscles, beginning as single masses, become divided, at their remote
ends, into two or more muscular tendinous slips. <A division of a muscle
into two parts by an intermediate tendon gives the form called digastric
or biventral, and there are some muscles in which a greater number of
parts are thus separated by what have been called tendinous inscrip-
tions.

in the description of the muscles it is customary to state the attach-
ments of their opposite ends under the names of origin and isertion ;
the first term being usually applied to the more fixed, or in the case of
the limbs the proximal extremity, and the second to the more movable
or remote attachment ; but it is to be observed, that it is often diffi-
cult to lay down a rule for the correct use of these terms, and that in
the great majority of instances it is of importance to consider the
action of a muscle as it may affect the motions of the parts attached
not to one only but to both of its extremities.

The study of the actions of the muscles either singly or in groups,
though strictly a physiological subject, cannot be separated from their
anatomical description. With respect to this the following general
principles ought to be kept in view. Ist. That the force exerted by any
muscle during its contraction is in proportion to the mwmber of mus-
cular elements or fibres composing the muscle. 2nd. That the extent
of motion, in so far as it merely depends on the shortening of the fibres
of the muscle, is in proportion to the length of the fibres. And 38rd.
That the direction of the force produced by a contracting muscle
is in the line of the axis of the whole muscle if it run straight between
its opposite points of attachment, but in the line of the portion attached
to the moving part if the muscle or its tendon be bent in its course. In
most instances of such deflection from the straight course the muscles
or their tendons run in loops or in grooves somewhat after the manner
of a pulley. The loops are either fibrous or cartilaginous. In the
pulley-like disposition of tendons running over bones, there are fre-
quently fibrous or cartilaginous or bony nodules developed at the place
of angular bending of the tendons. The name sesamoid, originally
given to the small bones developed in some of the digital tendons,
has been applied generally to all similar intratendinous structures.

It is further to be observed that the direction in which the muscular
fibres or fasciculi run in a muscle is very frequently not that of the axis
of the muscle, nor do the muscular fasciculi in the great majority of
instances extend from end to end ina muscle. On the contrary, the
muscular fibres and fasciculi are much oftener comparatively short, and
are attached within the length of the muscle to prolongations of the
main tendons or to other tendinous bands which intersect its substance ;
and thus the muscular fibres run into these tendinous parts with various
degrees of obliquity to the axis of the muscle.

The muscular flesh forms a large proportion of the weight of the
whole body. This proportion has heen carefully determined by mea-
surements recently published by Dr. G. v. Liebig (Archiv. fur Anat. u.
Physiol. 1874, p. 96), from whose tables the following is calculated

GENERAL MORPHOLOGY OF THE MUSCLES. 185

for a man of 150 lbs. weight: skeleton, 27 lbs. ; muscles, 63 lbs. ;
viscera (with skin, fat, blood, &c.), 60 lbs.

General Morphology.—It cannot be doubted that the disposition of the
muscles, as a whole and in groups, originally bears a close relation to the plan
of vertebrate organization in the skeleton. This is very perceptible in the earlier
stages of foetal development and in the lowest vertebrate animals. In fishes
especially, and partly in amphibia, the muscles present a remarkable degree of
vertebrate segmentation, the greater part of the muscles of the trunk being
subdivided into zones, or myotomes, by partitions or selerotomes, partly bony
and partly cartilaginous or membranous, which extend transversely through the
walls of the trunk, and which correspond in number and position with the
vertebral and costal segments. In the higher animals and in man, together
with the greater specialization of muscles in connection with the development
of limbs, great deviations from the primitive muscular type in the trunk have
occurred, and it becomes extremely difficult to trace the morphological relations
of the rest of the muscles in the axial part of the body. It is indeed only in
the deeper muscles of the vertebral column and of the ribs that the vertebrate
subdivision and relation remain in any degree apparent. In the more super-
ficial muscles, and more especially in the muscles of the limbs, where the direc-
tion of the fibres is generally outwards from the trunk, portions of the myotomes
run together so as to form muscles of greater or less length, and in which all
appearance of vertebrate division is effaced. In their more general relations
also to the trunk of the body two sets of the muscles may be distinguished
as cpaxvial and hypavial (episkeletal and hyposkeletal of Huxley), according as
they lie above or below the embryonic vertebral axis and the plane of its lateral
extension. The hypaxial muscles, comparatively little developed in man, com-
prise chiefly the prevertebral muscles of the neck with the psoas and pyriformis.
Of the epawrial muscles a dorso-lateral division consists mainly of the long and
short erector muscles of the spine and head ; while a ventro-latcral division con-
sists both of such ventral longitudinal muscles as genio-hyoid, sterno-hyoid, and
recti abdominis,.and of the lateral, obliquely directed, sterno-mastoid, scalene,
intercostal, and abdominal muscles. The muscles of the limbs are also primarily
derived from this great ventro-lateral muscle. They may be distinguished as
extrinsic When attached partly to the limbs and partly to the trunk, and as
intrinsic when wholly attached to the bones of the limbs and their arches.

To these morphological relations further reference will hereafter be made
under the several large divisions of the muscles. (See Humphry, “ Observations
in Myology,” &c., 1872, and in various papers in the Journ. of Anat.; Huxley,
“ Anat. of Verteb. Animals,” and Mivart, ‘‘ Lessons in Elementary Anatomy.”

Varieties.—It follows from what has been stated above, that homologous
correspondence can be traced between the individual muscles and groups of
muscles of man and those of animals. But as the form and attachments
of the muscles are subject to very great variations in different animals, as well as
to occasional varieties in the same species, the determination of the special homo-
logies is attended in many cases with great difficulty, and is still very imperfect.
Many varieties have also been observed in the human body, and it is interesting
to notice that these varieties are found to reappear generally in the same form,
or in modifications of it which indicate relations to a typical or fundamental
structure; and that many of them are thus more or less repetitions of forms
known to exist in different species of the lower animals. (Consult John Wood
in Proceedings of Roy. Soc. 1864-7, and Turner and others in Journ. of Anat. &
Physiol. ; Macalister’s Instructive Catalogue of Muscular Anomalies, in Trans.
Roy. Irish Acad., 1872, and other papers; Hallet, in Edin, Med. Journ., 1845 ;
Wenzel Gruber, in Mem. of the Petersburg Acad.)

FASCIA.

The term Fascia is applied to parts presenting a membranous dispo-
sition of reticulated or felted fibrous tissue. ‘These structures have
usually been distinguished as the swperficial and the deep; the former
consisting of looser and finer material, and passing by their slenderer

186 FASCIA IN GENERAL.

kinds into the looser varieties of connective tissue ; while the latter,
denser in character, frequently exhibit more or less regular arrangements
of strong white fibres, giving them a shining appearance, and are often
termed aponeuroses.

Superficial Fascia.— Under this name, or as subcutaneous fascia, is
described the layer of loose tissue of varying density, which is placed
immediately below the skin, all over the body. It is the web which
contains the subcutaneous fat, the panniculus adiposus, and in some
regions superficial muscles, as the panniculus carnosus, From the sub-
cutaneous tissue of the eyelids, however, as well as from that of the penis
and scrotum, adipose matter is entirely absent. Beneath the fatty layer
of the superficial fascia, which is immediately subcutaneous, there is
generally another layer of the same structure, comparatively devoid of
adipose tissue, in which the trunks of the subcutaneous vessels and
nerves are found. When the subcutaneous fat becomes absorbed, the
stroma in which it was deposited is still left, and its meshes approach
one another, so that in lean subjects a more fibrous condition of the
superficial fascia is found than in others.

Deep Fascie and Aponeuroses.— Under the name of deep fascia is
comprehended that stronger layer of fibrous or connective tissue which,
lying close to the muscles, invests them, or dips between them, and
forms a nearly continuous covering of the body beneath the superficial
fascia. It is chiefly to the stronger parts of this fascia that the name
of aponeuroses has been given. ‘Those covering the muscles have been
named aponeuroses of investment (Bichat), to distinguish them from
proper tendinous expansions, or aponeuroses of insertion, of muscles.
This distinction, however, is far from being universally applicable: apo-
neuroses of insertion are often continued into aponeuroses of invest-
ment, as in the instance of the gluteus maximus, or into softer fascia,
as at the lateral parts of the occipito-frontal aponeurosis. The principal
aponeuroses of investment are those which incase the muscles of the
limbs, binding them down in a common sheath, and connected in various
places by septa with the bones. They are characteristic of the limbs,
there being no structure entirely corresponding to them in the rest of
the body. Parts of the deep fascice in the vicinity of the larger joints
as at the wrist and ankle, become strengthened into tight transverse
bands, which serve to hold the tendons close to the bones, and hence
receive the name of reX/inacula.

Synovial Sacs and Sheaths: Burse Mucosz.—In various situ-
ations where the tendons of muscles pass over the prominences of
bones, or run in fibrous sheaths, synovial cavities exist, either of a
vesicular or tubular form, thus forming the synovial burse or sheaths.
In many such instances a true synovial membrane appears to cover the
adjacent surfaces, and diminishes their friction in moving on each
other. In other places less defined spaces exist in the connective tissue
between parts of the tendons or fasciz, and occasionally between parts
of the skin and the harder or more prominent structures on which they
lie. In some of these subcutaneous burs a distinct synovial mem-
brane cannot be found ; but there are probably gradations of transition
between these bursal spaces and those which are lined by synovial mem-
brane. Some of the synovial sacs and sheaths of tendons in the
vicinity of joints communicate freely with the articular cavities. (See
Gen. Anat., vol. il. p. 201.)

MUSCLES OF THE UPPER LIMB. 187

I—MUSCLES AND FASCIL# OF THE UPPER LIMB.

A certain number of muscles situated superficially on the trunk pass
to the bones of the shoulder and humerus, so as to attach the upper
limb to the body. These muscles, from their position, form a division
of the muscles of the trunk, but considered with reference to their
destination and action they may be held as belonging to the upper
limbs, and will therefore be so described in the present section. The
muscles referred to are, posteriorly, the trapezius, latissimus dorsi,
the rhomboidei, and levator anguli scapuls ; and, unteriorly, the two
pectoral muscles, the subclavius, and the serratus magnus. Along with
these might also be included the clavicular part of the sterno-cleido-
mastoid muscle and the omohyoid ; but as these last have important
relations with parts situated in the neck, they are more conveniently
described among the muscles of that region.

I. BETWEEN THE TRUNK AND THE UPPER LIMB POSTERIORLY.

Fascta:.—The superficial fascia covering the muscles which pass
from the trunk to the shoulder and upper limb posteriorly forms a
layer of considerable strength with embedded fat lying below the
skin : it is continuous with that of the neck above, that of the axilla

‘and breast in front, and that of the abdomen and hips below.

The deep fascia of the back forms a dense fibrous layer closely invest-
ing the superficial muscles to which it furnishes sheaths: at the outer
margins of the trapezius and latissimus dorsi muscles it is continuous
with the deep fasciz of the neck, breast, axilla, and abdomen, and turns
round beneath the edges of the muscles so as to complete their
sheaths and separate them from the subjacent layer of muscles. It is
attached to the skeleton along the line of the spines of the vertebre,
and dorsum of the sacrum, to the occipital bone, the spine of the scapula,
and the crest of the ilium.

In the loins there is a strong, flat, shining tendinous structure called °
the lumbar aponeurosis, to which the latissimus dorsi and other muscles
are attached posteriorly ; but this will be most conveniently described
along with the muscles of the back.

Muscies.—The trapezius muscle (cucullaris) arises by a thin apon-
eurosis from the protuberance of the occipital bone, and the inner third of
its superior curved line, from the ligamentum nuchee, and from the
spines of the last cervical and all the dorsal vertebraz, as well as from the
supraspinous ligaments. From this extended line of origin the fibres
converge to their insertion : the superior fibres, descending and turning
forwards in the neck, are inserted into the external third of the clavicle
at its posterior border ; the succeeding fibres pass transversely to the
inner border of the acromion process and upper border of the spine of
the scapula, while the inferior fibres, ascending obliquely, terminate in a
flat tendon which glides over the triangular area at the base of the spine
of the scapula, and is inserted into the rough mark at the root
of the spine. The greater part of the line of origin presents only
a small admixture of tendinous fibres, but opposite the seventh cervical

188 MUSCLES OF THE UPPER LIMB.

Fig. 163.

4

TRAPEZIUS. LATISSIMUS DORSI. 189

Fig. 163.—Superrician Muscies oF THE TrunK, SHouLDER anp Hp, VIEWED FROM

BEHIND. (A.T.) 2

a, external occipital protuberance ; 6, acromion of the scapula ; ¢, crest of the ilium ;
1, trapezius ; 1’, oval tendon of the two muscles in the upper dorsal and lower cervical
region ; 1”, triangular tendon of insertion ; 2. latissimus dorsi; 2’, 2,’ its costal origins

gah)

and its direct origin from the crest of the ilium ; 1, 2’, c, the posterior layer of the
lumbar aponeurosis ; 3, sterno-mastoid ; 4, deltoid ; 5, infraspinatus ; 6, teres minor ;
7, teres major ; 8, rhomboideus major ; below this on the left side is seen a triangular
space bounded by the rhomboid, trapezius, and latissimus dorsi muscles, in which a part
of the seventh rib may be felt; on the left side, the arm and shoulder being elevated,
the space is enlarged so as to show a part of the sixth and seventh ribs ; 9, back part of
the external oblique muscle of the abdomen ; between 9 and 2’, a small part of the
internal oblique ; 10, part of the gluteus medius covered by the fascia lata; 11, gluteus
maximus ; 12, gracilis ; 13, small part of the adductor magnus; 14, semitendinosus ;
15, biceps ; 16, fascia lata covering the vastus externus.

spine, and for the distance of several vertebrae above and below that
point, a flat tendon extends outwards, widest at the middle of the space
and narrowing towards the upper and lower ends, so that the apo-
neuroses of the two muscles taken together have an elliptical form.
The fibres of origin from the occipital bone have little or no tendinous
lustre. The muscles of the two sides have together the form of a four-
sided figure, or shawl or cowl, pointing downwards : hence the name of
cucullaris which has been given to it.

Relations.—The trapezius is superficial in its whole extent: it covers the
splenius, the greater part of the complexus above the splenius, the levator anguli
scapule, the rhomboidei, the supraspinatus, and small portions of the infra-
spinatus, latissimus dorsi, and lumbar aponeurosis. The spinal accessory nerve,
and the superficial cervical artery, pass into it from its deep surface.

Varieties.—The trapezius is subject to considerable variations in its attach-
ments : it is not unfrequently shorter than above described, and the number of
dorsal vertebrae with which it is connected is sometimes diminished to six or
seven, or even fewer. Its occipital attachment is occasionally wanting ; and
sometimes a separation exists between its cervical and dorsal portions, in the
same manner as in some of the rodent animals. These varieties affect either
one or voth sides.

The latissimus dorsi muscle arises by tendinous fibres from the
spinous processes of the six or seven lowest dorsal vertebrae, and from
the posterior layer of the lumbar aponeurosis, through the medium of
which it is attached to the lumbar and upper sacral spines and back
part of the iliac crest ; it also arises by fleshy fibres for an inch or
more from the iliac crest in front of the outer margin of the lumbar
aponeurosis, and from the last three or four ribs by narrow fleshy slips
which inter-digitate with the attachments of the external oblique mus-
cle of the abdomen. The fibres at the upper part are the shortest, and
pass almost horizontally outwards over the lower angle of the scapula,
from which they generally receive a small slip of fleshy fibres ; those
lower down become longer and pass more obliquely upwards ; finally,
those which are attached to the ribs ascend almost vertically. By this
convergence the fibres of the muscle come to form a narrow band of
some thickness, which, accompanying the teres major towards the
axilla, winds round the lower and outer border of that muscle so as
finally to be placed in front of it. It terminates in a flat tendon of about
two inches in length, which is adherent at its lower border to that of
the teres major, but is again detached from it previous to its insertion, a
synovial bursa intervening between them. The tendon is attached to the

190 MUSCLES OF THE UPPER LIMB.

Fig. 164.—ScprrrictaL VIEW or
THE MuscLes or THE TRUNK,
SHovutpEr anv Hrp. (After Bour-
gery.) (A. 7.) 2

0, occipital protuberance ; C,
transverse process of the atlas ; D,
first dorsal vertebra ; L, first lum-
bar vertebra ; §, first piece of the
sacrum ; Co, first piece of the
coccyx ; a, acromion; 6b, base of
the scapula ; 7, crest of the ilium ;
1, upper and back part of the sterno-
mastoid muscle; 2, splenius, levator
anguli scapule, and other deep
muscles; 38, 3, upper and lower
ends of the line of origin of the
trapezius muscle; 3’, triangular
tendon attached to the inner end of
the spine of the scapula; +, half of
the oval tendon helonging to the
two trapezius muscles in the lower
cervical and upper dorsal region ;
4, 4, latissimus dorsi; 4’, 4”, line
along which the latissimus dorsi
takes origin from the lumbar fascia ;
5, infraspinatus ; 6, teres minor ;
7, teres major ; 8, deltoid ; 9, ex-
ternal oblique muscle of the ab-
domen; 10, gluteus medius, covered
by the aponeurosis of the fascia
lata ; 11, 11, line of origin of the
gluteus maximus from the posterior
part of ilium to the coceyx; 11’, |
its insertion into the fascia lata |
over the trochanter major; 11”, a |
part of its insertion into the femur ;

12, biceps; 13, semitendinosus ;
14, adductor magnus ; 16, gracilis.

floor of the bicipital groove
of the humerus, a little
higher than the insertion of
the teres major. From this
twisting of the muscle upon
itself, the anterior surface of
the tendon is continuous
with the posterior surface of
the rest of the muscle.

Relations. — The latissimus
dorsi is subcutaneous, except atits
origin from the dorsal vertebra,
where it is covered by the
trapezius, and at its insertion,
where it dips into the axilla.
Tt rests on part of the rhom-
boideus major and infraspina-
tus, on the teres major, serratus
posticus inferior, vertebral apo-
neurosis, external intercostal
muscles, and the posterior bor-
ders of the external and internal
oblique muscles.

LATISSIMUS DORSI. 191

Between the adjacent borders of the latissimus dorsi, trapezius, and rhom-
boideus major, there is left, when the scapula is drawn forward, a triancular area
in which a portion of one or ' ¥
two ribs and of an intercostal
space becomes superficial ; this
is taken advantage of for the
purpose of auscultation.

Fig. 165.

Fig. 165.—Drrper View oF THE
Musctres oF THE £TRUNK,
SHounper anv Hip. (After Bour-
gery.) (A.T.) +

The trapezius, latissimus dorsi,
deltoid, gluteus maximus and ex-
ternal oblique muscles have been
removed. ‘The bones are lettered
as in the preceding figure.

1, splenius capitis and splenius
colli; 1’, lower end of splenius
colli ; 2, complexus near its inser-
tion; 3, levator anguli scapule ;
4, rhomboideus minor ; above it +,
a part of the serratus posticus supe-
rior; 5, rhomboideus major ; 6, part
of the longissimus dorsi ; 6’, part of
the tendons of insertion of the
sacro-lumbalis ; 7, part of the spi-
nalis dorsi ; 8, upper, and 8’, lower
part of the serratus posticus infe-
rior ; 9, obliquus abdominis inter-
nus ; 10, supraspinatus ; 11, infra-
spinatus ; 12, placed upon the long
head of the triceps, points to the
teres minor ; 13, teres major ; 14,
serratus magnus; 15, gluteus
medius ; 16, pyriformis ; 17, portion
of the obturator internus ; + and +,
superior and inferior gemelli ; 17’,
the intra-pelvic portion of obturator
internus ; 18, the tendon of the obtu-
rator externus passing to its inser-
tion ; 19, quadratus femoris ; 20,
upper part of the adductor magnus.

Varieties. — The number of
dorsal vertebrae to which the
latissimus dorsi is attached
varies from four to seven or
eight, and the number of the
costal attachments is also incon-
stant, being frequently dimin-
ished and more rarely increased.
Muscular bands (avillary arches)
are sometimes seen to stretch from
the border of this muscle across
the axilla to its anterior part,
where they terminate various-
ly, in the tendon of the greater
pectoral, in the coraco-brachialis
muscle, the biceps, or in the
fascia. There is also occasion-
ally a slip of attachment to the scapular part of the triceps.

192 MUSCLES OF THE UPPER LIMB.

The rhomboidens minor, a comparatively narrow muscle, arises
from the spinous processes of the seventh cervical and first dorsal
yertebree and from the ligamentum nuche. It inclines downwards and
outwards, and is inserted into the base of the scapula opposite the
triangular surface at the commencement of the spine.

The rhomboideus major, much broader than the preceding muscle,
lies immediately below and in contact with it. It arises from the
spinous processes of the four or five upper dorsal vertcbree and their
interspinous ligaments, and is inserted into that part of the base of the
scapula which is included between the spine and inferior angle. A
considerable part of the attachment at the insertion is only by firm
connective tissue, and the most of the fibres, instead of being fixed
directly to the bone, end in a tendon which is connected to the scapula
near the lower angle; in consequence of this arrangement, the muscle
may, in part, be separated from the bone without division of its mus-
cular or tendinous fibres, and must therefore act most immediately on
the lower angle.

Relations —The greater part of the rhomboidei muscles is covered by the
trapezius, a small angular portion only of the rhomboideus major being sub-
cutaneous in the interval between the trapezius and latissimus dorsi; the extent
of this portion varies with the position of the scapula, being increased when the
arm and shoulder are raised from the side. The rhomboidei cover the greater
part of the serratus posticus superior, and the posterior scapular artery descends
on their deep surface.

Varieties ——Both rhomboid muscles are liable to variations in the extent of
their vertebral and scapular attachments. An additional muscle has been observed
running close and parallel to the upper border of the minor, from the scapula to
the occipital bone, and has been called rhomboideus occipitalis atter a similar
muscle occurring in some animals.

The levator anguli scapule arises by slightly tendinous slips
from the posterior tubercles of the transverse processes of the four
or five upper cervical vertebree, between the attachments of the
splenius and scaleni muscles, and forms an elongated fleshy mass which
is angened into the base of the scapula from the spine to the superior
angle.

Varieties. —The number of vertebral attachments of the levator anguli
scapule is subject to some variation. A slip has been observed to extend to it
from the occipital or from the mastoid process of the temporal bone (Theile),
and from the second rib (Meckel). It often appears as a divided muscle, the
parts connected with the several vertebrae remaining separate, even to the place
of insertion. It is occasionally connected by slips with the trapezius, scalene,
or serrated muscles. In quadrupeds it is united with the serratus magnus, so as
to form a single muscle.

Nerves of the preceding muscles.—The trapezius muscle receives its nerves
from the spinal accessory which enters it on the deep surface, after being
joined by branches from the third and fourth cervical nerves, from these nerves
directly, and probably also from the posterior branches of the cervical and
dorsal spinal nerves as they pierce it. The latissimus dorsi is chiefly supplied
by the long subscapular nerve of the brachial plexus, but may also receive twigs
from the dorsal and lumbar nerves which pass through it. The nerves of the
rhomboid muscles proceed in one or sometimes two branches from the fifth
cervical, and the levator scapulz is supplied from the third, and sometimes
also from the fifth, cervical nerves,

THE PECTORAL MUSCLES. 193

TW. BETWEEN THE TRUNK AND THE UPPER LIMB ANTERIORLY.

Fasci2.—The superficial fascia of the pectoral region encloses the
mammary gland, covering it both in front and behind, and sending
strong septa in between its lobes. Processes likewise extend forwards
from the fascial investment of the gland, between the masses of fat, to
the skin and nipple, thus affording support to the gland.

The deep fascia of the pectoral region is continuous with that of
the neck both before and behind the clavicle, ‘and with the similar
structure spreading over the shoulder and thorax. As belonging to the
deep fascia there may be specially noticed the costo-coracoul membrane,
which is a distinct layer of firm fascia, attached superiorly to the
clavicle and giving a firm covering to the subclavius muscle. Its
strong lower margin, distinguished sometimes as the costo-coracoid
ligament, extends from the coracoid process to the first rib at the origin
of the subclavius muscle. The deep fascia, continued from this struc-
ture inferiorly, is narrowed like a funnel, and becomes thinner as it
descends upon the surface of the axillary vessels, forming the anterior
part of the sheath of those vessels, while the posterior part is formed
by a deep process of the cervical fascia.

The axillary fascia is a strong membrane stretched across the
axilla, and so disposed as to maintain the skin in position over that
hollow. Beneath the pectoralis major muscle is a layer of fascia attached
to the chest in front of the costo-coracoid membrane: it divides into
two layers to enclose the pectoralis minor, and, these reuniting, it con-
tinues to pass outwards as a strong membrane between the pectoralis
minor and short head of the biceps muscle ; lower down it is joined
by the fascia covering the pectoralis major, which is folded round the
margin of that muscle, and, thus strengthened, it slopes outwards
and backwards to the inferior border of the scapula, where it is joined
by the sheaths of the latissimus dorsi and teres major muscles. In
the deepest part of the axilla the fascia is perforated by numerous
blood-vessels and lymphatics. At the outer side occupied by the
large vessels and nerves of the limb, it is continuous with the sheath
of the vessels and with the aponeurosis of the arm. ‘The density
of this fascia offers a considerable obstacle to the progress of axillary
abscesses to the surface.

Muscies.—The pectoralis major muscle arises from the anterior
and lower surface of the sternal half of the clavicle ; from the anterior
surface of the sternum ; from the cartilages of the second to the sixth
ribs, and also the bony part of the sixth rib ; and from the aponeurosis
of the external oblique muscle of the abdomen. Its fibres form a thick
mass, and converge to be inserted by a tendon of considerable breadth into
the outer bicipital ridge of the humerus. At the axillary border the
muscular fasciculi, especially those of the pectoral part, are folded back-
wards, so that the lower fibres successively disappear from view, and
the insertion into the humerus takes place by a broad flat tendon which
is doubled upon itself in two close parallel lines, open above and con-
nected below. The clavicular fasciculi are for the most part inserted on
the outer surface of the anterior fold of the tendon, but they are also
continued by independent tendon directly to the humerus. The posterior
fold of the pectoral tendon is usually considerably broader than the

anterior, and thus its line of attachment rises higher on the humerus.
VOL. I. %

194 MUSCLES OF THE UPPER LIMB.

Fig. 166.

if

Fig. 166.—SvPERrictan view oF THE Muscies oF THE TRUNK, FROM BEFORE. (A.T.)!
1, sterno-mastoid of the left side ; 1’, 1‘, platysma myoides of the right side ; 2, sterno-

PECTORALIS MAJOR MUSCLE. 195

hyoid ; 3, upper, 8’, lower belly of the omo-hyoid ; 4, levator anguli scapule ; 4’, 4”, scalene
muscles ; 5, anterior part of the trapezius ; 6, deltoid ; 7, upper part of the triceps brachii
in the left arm; 8, teres minor; 9, teres major; 10, latissimus dorsi ; 11 pectoralis
major ; 11’, on the right side its clavicular portion ; 12, part of the pectoralis minor ; 13,
serratus magnus ; 14, external oblique muscle of the abdomen ; 35, placed on the
xiphoid cartilage at the upper end of the linea alba; 15’, is placed on the umbilicus ; 16,
is placed over the symphysis pubis, and at the lower end of the linea alba, above 16,
the pyramidal muscles are seen through the abdominal aponeurosis ; 15 to 17, the
linea semilunaris at the outside of the rectus muscle, the transverse tendinous lines of
which are seen through the abdominal aponeurosis ; 18, part of the gluteus medius ; 19,
tensor vagine femoris ; 20, rectus femoris ; 21, sartorius 3 22, femoral part of the iliacus
and psoas ; 23, pectineus ; 24, adductor longus; 25, gracilis. On each side of 16, the
external abdominal ring is indicated.

It is further prolonged upwards by a slip which runs over the bicipital
groove to the great tuberosity, and gives an offset to the head of the
humerus. The lower or doubled end of the tendon is closely united
with the insertion of the deltoid, and a slip is prolonged from its inferior
margin to the fascia of the arm.

Fig. 167.—VIEw oF soME OF Vig. 167.
THE DEEPER MuscLes oF
THE SHOULDER AND TRUNK,

FROM BEFORE. (A.T.) }

On the right side the pec-
toralis major and external
oblique muscles have been re-
moved. a, coracoid process of
scapula; 6, manubrium of
sternum; ¢, c, cartilages of
the fifth ribs; d, ensiform
portion of the sternum ; 1,
upper part of the levator anguli
scapule muscle; 2, on the
middle of the clavicle, points
to the subclayius muscle; 3,
pectoralis minor ; 4, subscapu-
laris ; 4’, its insertion into the
lesser tuberosity of the hume-
rus; 5, coraco-brachialis cut
short; 6, coracoid, and 6’ glenoid
head of the biceps brachii, both
cut short near the place where
they unite into one muscle ; 7,
on the tendon of the latissimus
<lorsi, points by a line to the ten-
don of the teres major, both
cut short and passing to their
insertion inside the bicipital
groove ; 8, folded tendon of the
pectoralis major; 9, insertion
of the deltoid ; 10, brachialis
anticus, embracing the insertion
of the deltoid ; 11, part of the inner head of the triceps, the middle head of which is
seen passing behind the tendons of the latissimus and teres ; 12, 12, on the fifth and
eighth ribs, point to the insertion of the serratus magnus ; 13, 13', recti abdominis.

~

Relations.—The folded inferior border of the pectoralis major forms the ante-
rior margin of the axilla; the superior runs parallel with that of the deltoid
muscle, from which it is separated only by a slight interval which becomes wider
towards the clavicle, and in which run the cephalic vein and the humeral branch
of the acromio-thoracic artery. The anterior surface is subcutaneous in the
greater part of its extent being covered only by some of the fibres a the

a)

196 MUSCLES OF THE UPPER LIMB

platysma myoides and by the mamma. The posterior surface rests chiefly on the
pectoralis minor, and with that muscle forms the anterior wall of the axilla.

Varieties. — The more important varieties of this muscle consist in the greater
or less extent of its attachments to the ribs or sternum, and the greater or less
union or separation of its clavicular, sternal, and costal parts. The clavicular
part has occasionally been observed to be absent, or to be incorporated completely
with the deltoid. The tendinous and fleshy fibres of origin of opposite sides
sometimes meet and even decussate in front of the sternum. In some instances
additional muscular slips take origin from the aponeurosis of the external oblique
muscle, and in others the lower part of the muscle presents considerable deficiency.
Sometimes also slips connect the great pectoral with the biceps muscle. The
slips of connection with the latissimus dorsi have already been noticed.

As closely related to the great pectoral muscle there may be noticed here the
muscular band which has been observed by Wood, Struthers, Macalister, and
others, passing from a fascial origin over some of the lower true and upper false
ribs to a very variable tendinous or aponeurotic insertion at some place along the
inner border of the arm, or even as far down as the inner condyle of the humerus,
and which has been named chond7ro-epitrochlearis.

The pectoralis minor muscle arises from the upper margins and
external surfaces of three ribs near their cartilages—usually the third,
fourth, and fifth—and from the neighbouring parts of the intercostal
aponeurosis. Its fibres converge to a narrow tendon, which is inserted
into the anterior half of the inner border and upper surface of the
coracoid process, in contact with the conjoined origin of the coraco-
brachialis and biceps muscles.

Relations —This muscle is covered by the pectoralis major, and forms a part of
the anterior wall of the axilla. It crosses the axillary artery and brachial plexus
of nerves, When the arm is much raised a portion of the muscle may be seen
below the outer margin of the pectoralis major.

Varieties—The pectoralis minor is sometimes found split up or subdivided
into as many pieces as it has of costal attachments. The place and number of
the costal slips are subject to slight variation. The tendon of insertion is not
unfrequently detached from the coracoid process, and carried on by the coraco-
acromial ligament to the acromion process or some other neighbouring part.

The subclavius muscle arises by a short thick tendon from the first
costal arch at the junction of the rib and cartilage, close to the costo-
clavicular ligament. From this tendon its fibres pass outwards and
upwards, forming a rounded belly, which is inserted into the groove
along the inferior surface of the clavicle, extending as far as the recess
between the conoid and trapezoid parts of the coraco-clavicular ligament.

Relations —The subclavius is covered in front by the costo-coracoid fascia, and
is placed immediately over the axillary vessels and nerves.

Varietics.—The subclavius is sometimes found to be without any attachment
to the clavicle, being inserted into the root of the coracoid process ; or it may
have a double insertion, the upper into the clavicle, the lower into the coracoid
process.

The serratus magnus muscle, placed upon the upper and lateral
part of the thorax, between the ribs and the scapula, is attached
anteriorly by nine fleshy angular slips to the first eight or sometimes
nine ribs, two of these being connected with the second rib; it also
derives some fibres from the aponeurosis covering the upper intercostal
spaces. Posteriorly, the muscle, considerably narrowed, is attached to
the line in front of the base of the scapula, and at the upper and lower
angles of the bone into the flat surfaces which are excluded from the
fossa of the subscapular muscle. The fibres are arranged in three sets,

en = a a

= ——

SERRATUS MAGNUS MUSCLE, 197

thus :—a, those from the first and second digitations form a thick
bundle which terminates on the flat area in front of the upper angle of

Fig. 168.—LatTeran Vinw Fig. 168.
OF THE TRUNK, SHOW-
ING THE SERRATUS MAG-
nus Muscur. (A. T.)

a, coracoid process of
the scapula; 6, glenoid
cavity ; c, lower angle;
d, first dorsal vertebra ; I,
VI, XII, the first, sixth,
and twelfth ribs ; 1, upper
portion of the serratus
magnus attached to the
first and second ribs; 2,
second or middle portion
attached chiefly to the
third rib ; 3, lower or fan-
shaped portion attached to
the ribs from the fourth
to the ninth; 4, external
intercostal muscle ; 5, cos-
tal origins of the transver-
salis abdominis ; +, sca-
pular extremities of the
levator scapule and omo-
hyoid muscles.

the scapula ; }, those
of the third and fourth
digitations, but es-
pecially the first of these, which is the inferior digitation of the second
rib, spread out into a triangular iayer, the thinnest part of the muscle,
and are attached along the line in front of the base of the scapula,
extending from the place of insertion of the preceding part nearly
to the lower angle of the bone ; ¢, the remaining five or six digita-
tions converge in the form of a fan, and terminate posteriorly in a
thick mass, which is attached to the flat surface in front of the lower
angle of the scapula.

Relations.—By its deep surface, the serratus magnus rests on the upper ribs,
the intercostal muscles, and part of the serratus posticus superior. Its outer
surface is in contact posteriorly with the subscapular and latissimus dorsi
muscles, and forms anteriorly the internal wall of the axilla, being subcutaneous
in the lower part of its extent.

Varicties.—Not unfrequently the lowest slip of the muscle extends to the tenth
rib : in other instances the number of costal slips is diminished, occasionally by
the suppression of the first, but oftener by the absence of some of the lower
digitations, so that the muscle does not pass lower than the seventh rib. The
muscle has been observed divided into three parts : sometimes the middle part
is absent; and in various instances the serratus has been observed united
partially with the levator scapule, the external intercostals, or the external
oblique. With the levator scapule it forms one muscle in many mammals.

Nerves.—The nerves which supply the anterior muscles passing from the
trunk to the upper limb are all derived from parts of the brachial plexus.
The nerve of the subclavius is a small twig from a loop between the fifth
and sixth cervical nerves. The large nerve of the serratus magnus, called
posterior thoracic, proceeds from the same nerves and pierces the middle scalene
muscle. The nerves of the pectoral muscles, named anterior thoracic, are in two

198 MUSCLES OF THE UPPER LIMB.

sets, internal and external, proceeding respectively from the mner and outer
divisions of the plexus, the outer supplying the great pectoral muscle, the inner
both it and the lesser pectoral.

Actions of the muscles passing between the Trunk and Upper Limb.—-
Considered with reference to the movements of the limb upon the trunk, the
upper part of the trapezius, the levator scapula and the rhomboid muscles are
elevators of the shoulder ; the lower part of the trapezius, the pectoralis minor,
and the subclavius are depressors; the serratus magnus as a whole carries for-
ward the base of the scapula, and the rhomboidei draw it back; the latissimus
dorsi and pectoralis major depress the humerus and carry it towards the middle
line, behind or in front, according as the one or other muscle is in action.

More particularly, the superior fibres of the trapézius elevate the clavicle ; the
middle fibres acting on the acromion have also some elevating action, but
tend rather to carry back the scapula towards the spine ; the inferior part of the
muscle acting upon the spine of the scapula would of itself depress that bone
while it carried it inwards towards the dorsal spines, but acting in concert with
the upper two-thirds of the muscle, a rotation is produced in the scapula round
a central point, in such a manner that while the whole bone, and more especially
the acromion, is raised and carried towards the dorsal spines, the upper angle of
the scapula is somewhat depressed and carried inwards, while the lower angle is
carried outwards and elevated.

The levator anguli scapula and rhomboidei elevate the superior angle and base
of the scapula, thus counteracting in some degree the rotating action of the
trapezius. In this manner, when the trapezius, levator, and rhomboid muscles
act together, the scapula is raised without rotation, and its base is carried at
the same time inwards towards the dorsal spines.

The subclavius depresses the clavicle, and may also act as a support to the
sterno-clavicular articulation.

The pectoralis minor draws the coracoid process downwards and forwards,
and tends to throw the lower angle of the scapula backwards.

The serratus magnus riuscle, by withdrawing the base of the scapula from the
spinal column, enables the arm when raised from the shoulder to be still farther out-
stretched, as in the movement termed extension in fencing. It comes powerfully
into action in all movements of pushing ; it likewise combines with the trapezius
in rotating the scapula. In forced inspiration, the scapula being fixed by the
muscles which attach it to the trunk posteriorly and superiorly, the serratus
magnus assists in dilating the chest by raising and expanding the ribs.

The latissimus dorsi carries the elevated arm downwards and backwards, rotat-
ing it at the same time inwards, so as to make the palm look backwards, thus
accomplishing such a movement as is made by the arm in swimming. By pass-
ing over the angle of the scapula it binds that process to the trunk, preventing
its projection backwards ; and by being folded round the outer border of the
scapula, it limits the projection outwards of the same angle when the arm is
raised.

The pectoralis major muscle, while it combines with the latissimus dorsi in
depressing the humerus from the raised position, opposes that muscle by drawing
the limb forwards. It is placed upon the stretch when the arms are thrown
backwards, and is most shortened when they are folded across the chest. In the
remarkable case of Groux, affected with congenital cleft sternum, when the
shoulders were fixed backwards, the action of the great pectoral muscles tended to
separate the two segments of the sternum, and increased the space in which the
motions of the heart could be observed through the integuments.

Considered as acting on the trunk from the upper limb in a fixed condition,
these muscles all tend to draw the trunk of the body towards the limb, as in
climbing, or other like efforts. The latissimus dorsi muscles, if acting on both
sides, carry the body upwards and forwards, as in the use of crutches. The
pectorales and latissimus dorsi are also muscles of forced inspiration, tending to
raise and expand the ribs, more especially when the shoulders are fixed and the
arms are elevated. The upper parts of both trapezii acting on the occipital bone
aid the sterno-mastoid muscle in throwing forward the chin; and if one muscle
only acts, it aids in rotating the head.

THE DELTOID MUSCLE.

MUSCLES AND FASCIZ OF
THE SHOULDER.

Fascit®.—The deep fas-
cia binds together the mus-
cles of the shoulder with
considerable firmness, and
over the back part of the
deltoid and infraspinatus.
muscles assumes a tendin-
ous appearance. A strong
and somewhat isolated por-
tion, bound down to the
posterior and axillary mar-
gins of the scapula, covers
the infraspinatus and teres
minor muscles as far as
they are left uncovered by
the deltoid muscle. On
reaching the posterior bor-
der of the deltoid muscle,
this aponeurosis divides in-
to two layers, of which the
deeper is continued beneath
the deltoid to the shoulder-
joint, and the more super-
ficial forms a thin aponeur-
otic covering of that muscle,
becoming more and more
slender as it passes for-
wards, and is attached to the
lower border of the spine.

Fig. 169.—Suprrrician Mus-
CLES OF THE SHOULDER AND
Upper Livsp, FROM BEFORE.
(AU@s). 2

1, pectoralis major; 1’, its
clavicular portion; 2, deltoid,
its clayicular part; 2’, its acro-
mial part; 3, biceps brachii ;
3’, its tendon of insertion; 3”,
its aponeurotic slip; 4, brachi-
alis anticus; 4’, its inner and
lower portion ; 5, inner head of
the triceps; 5’, lower part of
the same, seen arising from be-
hind the intermuscular septum.
The explanation of the remaining
references will be found in the
description of fig. 179.

Muscires.—The deltoid
muscle is of a triangular
form and coarsely fascicu-
lated, and extends from the
most prominent part of the
shoulder down a third of

Fig. 169.

qj

ae

PAE

Neamt

199

200 MUSCLES OF THE UPPER LIMB.

the upperarm. It takes origin in an extended line which may be divided
into three portions, viz., an anterior from the front of the external third
of the clavicle, a middle from the outer edge and point of the acromion,
and a posterior from the lower border of the spine of the scapula as
far back as the triangular surface at its inner end. ‘The fasciculi from
these several parts converge as they descend, and are inserted by a
strong thick tendon into the deltoid impression, a triangular rough
surface above the middle of the humerus, on its outer side.

The three parts, composing the deltoid muscle, differ somewhat in the disposi-
tion of the muscular fasciculi and the tendons. The anterior and posterior
portions are composed of long fibres which, arising directly from the clavicle and
spine of the scapula, are inserted into the outer surface of the marginal parts of
the inferior tendon. In the acromial portion, while some of the muscular fibres
spring directly from the bone, yet most of them arise in a penniform manner
from the sides of three or, more frequently, four tendinous septa, which pass
downwards into the substance of the muscle. These oblique fibres, running nearly
parallel to each other, are inserted in a similar manner into the sides of two, or
more frequently three, septa which pass from below upwards and alternate with
the upper septa. The oblique fibres, from the outside of the first and fourth upper
septa are inserted into the marginal parts of the main tendon. There are besides
wedge-shaped bundles of muscular fibres, rising directly from the acromion in
the intervals between the penniform bundles, which, are inserted into the tips of
the lower tendinous septa, and others which springing from the ends of the
upper tendinous septa, are directly inserted into the humerus between the lower
septa. The main tendon of insertion spreads from below upwards for some
distance on the deep surface of the muscle.

Relations.—At the posterior border of the deltoid, the aponeurosis covering the
infraspinatus muscle divides into two thin layers, of which one covers the muscle
superficially, and the other lines its deep surface. At its anterior border this
muscle is in contact with the pectoralis major, the cephalic vein lying between
them. In immediate contact with the deep surface is the large bursa, which
separates this muscle and the acromion from the shoulder joint and the muscles
supporting it. The deltoid muscle covers the origins of the biceps, coraco-
brachialis, and long head of the triceps, and the insertions of the subscapularis,
supraspinatus, infraspinatus and teres minor muscles, as also the circumflex
vessels and nerve.

Varieties.—The deltoid muscle is not subject to great varieties. One of the
commonest is a greater degree of subdivision of its parts than usual, Another
is the continuation into it of fibres from the trapezius, as in animals wanting the
clavicle. Occasionally its anterior part is closely united with the great pectoral
muscle. Its insertion varies sometimes in extent. A remarkable prolongation of
its tendon on the radial border of the forearm, as far as the insertion of the
supinator longus, seems to repeat the tensor plicae alaris of the bird. (Macalister).

The supraspinatus muscle arises from the whole of the supraspinous
fossa of the scapula to within a short distance of the neck of the bone,
and from an aponeurosis by which it is covered. Its fibres converge beneath
the acromion to a tendon, which adheres to the capsule of the shoulder-
joint, and to the tendon of the infraspinatus muscle, and is inserted
into the upper of the three facets on the great tuberosity of the humerus.

The infraspinatus muscle is of a triangular form, and occupies the
greater part of the infraspinous fossa. It arises from the fascia covering
it, from the under surface of the spine, and from the dorsal surface of
the scapula in the fossa, except those parts at the lower angle and along
the external border, to which the teres muscles are attached. The fibres
converge to a tendon, which, concealed at first within the substance of
the muscle, is inserted into the middle facet of the great tuberosity of
the humerus.

THE TERES MINOR MUSCLE. 201

Relations.—The supraspinatus muscle is covered by the trapezius and the acro-
mion process. The suprascapular nerve and artery pass beneath it.

The infraspinatus muscle is bound down by the aponeurosis which superiorly
and externally divides so as to enclose the deltoid muscle. It is covered by the
deltoid at its upper and outer part, and by the trapezius at its upper and inner
part, by the latissimus dorsi at its lower angle, and in the intermediate portion it
remains superficial.

Varieties.—The infraspinatus muscle is sometimes very closely united with the
teres minor. The supraspinatus is very constant in its form and attachments.

The teres minor muscle is placed along the outer border of the in-
fraspinatus, and is intimately connected with that muscle. It arises by
a series of fibres from a ’
narrow obliquely grooved Fig. 170.
surface on the dorsum of
the scapula close to the
axillary border, and from
aponeurotic septa between
it and the infraspinatus
and teres major muscles,
and is inserted by tendon
into the greater tuberosity
of the humerus, immedi-
ately below the infraspina-

Fig. 170. — Muscurs oF THE
Richt SHovutpER AND ARM,
SEEN PROM BEHIND. (A. T.) J

The acromion process and a part
of the spine of the scapula, with
the deltoid muscle, have been re-
moved. a, coracoid process; },
triangular surface at the com-
mencement of the spine; c¢, is
close to the cut portion of the
spine ; d, greater tuberosity; ¢,
olecranon of the ulna; J, is close
to the external condylar eminence
and head of the radius; 1, supra-
spinatus muscle; 2, infraspinatus ;
3, teres minor ; below the figure
is the triangular space ; 4, teres
major; 5, part of latissimus dorsi ;
+, slip from the inferior angle of

the scapula; +, on the edge of sta oY |

the humerus, points to the ten- H GY)
don of the latissimus dorsi and | |W
the quadrangular space ; 6, scapu- \W

Jar head of the triceps, passing q Ny Hf \-
above between the teres major and \ tt Wp I}; ‘NW
minor ; 6’, outer head ; 6", part of Ww
the muscle rising below the spiral NN y

groove, continuous with the inner
head; 6”, part of the inner head ;
7, anconeus.

ies and by fleshy fibres into the bone for a short distance lower
own.

Relations.—This muscle is crossed behind by the deltoid. and in front is in
relation with the long head of the triceps, and the capsule of the shoulder-joint.

202 MUSCLES OF THE UPPER LIMB.

The dorsal scapular artery
passes between it and the bone.
At its lower border is the teres
major separated in part by the
long head of the triceps. A
bursa is sometimes found be-
tween the tendon and the
bone.

Fig. 171.—Suprrrrctan Muscirs
OF THE SHOULDER AND UPPER
LIMB, SEEN FROM BEHIND.

a, acromion ; 4, base of the sca-
pula ; c, tendon of the trapezius
muscle over the triangular surface
of the spine of the scapula ; d,
olecranon of the ulna ; e, external
condylar eminence; f, lower end
of the ulna; 1, trapezius; 2, acro-
mial part of deltoid; 2’, the part
of the same muscle rising from
the spine of the scapula; 3, rhom-
boideus major; 4, infraspinatus ;
5, teres minor; 6, teres major ;
7, latissimus dorsi; +, space be-
tween the trapezius, rhomboid and
latissimus muscles ; 8, triceps ex-
tensor cubiti ; 8’, its outer head ;
8’, part of its inner head ; 9, an-
coneus ; 10, part of the brachialis
anticus ; 11, supinator longus ;
12, extensor carpi radialis longior.
The explanation of the remaining
references will be found in the
description of fig. 182.

The teres major muscle
arises from the flat oval
surface on the dorsum of
the scapula near its inferior
angle, slightly from the
axillary border of the bone,
and from the septa inter-
posed between it and the
teres minor and infraspi-
natus. It is inserted by a
flat tendon about two
inches wide, into the inner
border of the bicipital
eroove of the humerus,
behind and in contact with
the tendon of the latissimus
dorsi, to which it is ad-
herent for a short space.
Close to the insertion, how-
ever, the tendons of these
muscles are separated by a
small bursa. The fibres
of the muscle are longitu-
dinal.

SUBSCAPULARIS. ACTIONS OF SHOULDER MUSCLES. 203

Relations —Posteriorly this muscle is covered at its lower part by the latissimus
dorsi, and at its upper part it is crossed by the long head of the triceps. The
outer side is surrounded obliquely by the latissimus dorsi; and the anterior
surface is concealed in the upper part of its extent by the tendon of that muscle.
The inner border of the muscle forms the margin of a triangular space, of which
the other sides are the upper part of the humerus, and the axillary border of the
scapula, covered before by the subscapular and behind by the teres minor muscles ;
this triangle is divided by the long head of the triceps into a supericr or external
quadrilateral, and an inferior or internal, triangular compartment. Through the
quadrilateral space pass backwards the posterior circumflex vessels and the circum-
flex nerve ; and in the triangular subdivision the dorsal branch of the subsca-
pular artery passes round the margin of the scapula into the infraspinous fossa.

Varieties—The teres major muscle is sometimes found connected with the
fasciculi of the latissimus dorsi arising from the same part of the scapula. A
slip from this muscle has also been observed descending upon the fascia of the
upper arm externally.

The subscapularis muscle arises partly by muscular and partly by
tendinous fibres from the venter of the scapula, with the exception of
the neck of the bone and the spaces occupied by the serratus magnus ;
its fibres unite into a broad tendon which perforates the capsular liga-
ment of the shoulder-joint, and is inserted into the small tuberosity
of the humerus. Some fleshy fibres also are directly inserted into the
bone for a short distance lower down. Three or four tendinous
septa, attached to the ridges of the subscapular fossa, pass outwards in
the origin of the muscle ; and others are prolonged inwards from the
tendon of insertion.

Relations —The tendon of the subscapularis is incorporated with the capsule
of the shoulder-joint, and between its upper and posterior surface, the coracoid
process, and the neck of the scapula is a bursa usually communicating with that
joint. There is also sometimes a bursa intervening between the anterior surface
of the muscle and the origin of the biceps and coraco-brachialis muscles. Ante-
riorly the muscle is in contact at its origin with the serratus magnus, and is
covered at its insertion by the coraco-brachialis and biceps, while, in the interval
between, it forms part of the posterior wall of the axilla.

Varietics—The varieties hitherto observed in this muscle are not considerable.
A small additional muscle, of somewhat variable form, has been described by
different authors, as passing from the surface of the subscapularis over the
capsular ligament, but without piercing it, to be inserted into or near the inner
margin of the bicipital groove, the subscapulo-capsularis of Wenzel Gruber.

Nerves of the Shoulder Muscles.—The supraspinatus and infraspinatus
muscles receive their nerves from the suprascapular branch which proceeds from
the upper loop of the brachial plexus, and therefore from the fifth and sixth
cervical nerves. The other muscles of this group are all supplied with nerves
from the posterior division of the plexus, as follows : the deltoid and teres minor
from the circumflex nerve, the teres major and the subscapularis from the middle
and short subscapular nerves.

Actions of the Shoulder Muscles.—The deltoid muscle raises the arm from
the side as far as the structure of the shoulder-joint permits, viz., till it is at
right angles with the trunk. Further elevation of the upper limb is effected chiefly
by the trapezius ; and it may be remarked that the insertion of that muscle cor-
responds exactly in extent to the origin of the deltoid, so that the two muscles may
be considered continuous in structure as well as in action. The anterior fibres of
the deltoid combine with the pectoralis major to draw the humerus forwards ; the
posterior assist in drawing it backwards. The supraspinatus, infraspinatus, and
subscapularis muscles being placed more closely round the joint, when acting in
concert with the deltoid, probably give steadiness and precision, while the deltoid
gives the main elevating force to the movement. The supraspinatus simply
elevates : the infraspinatus and subscapularis carry the arm backwards or {for-

204 MUSCLES OF THE UPPER LIMB.

wards when it is raised, and rotate it outwards or inwards when hanging by the
side. The teres major rotates the raised humerus inwards, the teres minor out-
wards : acting together, they assist in depressing the arm. The deltoid muscle
superficially, and the supra- and infraspinatus muscles, the teres minor and sub-
scapularis, more deeply, afford important protection to the shoulder-joint, and by
their tension prevent displacement of the head of the humerus.

MUSCLES AND FASCI@ OF THE UPPER ARM.

Fasct™.—The aponeurosis of the arm is composed chiefly of
transverse fibres, held together by others having an oblique or longitu-
dinal direction; it is thin over the biceps muscle, stronger where it
covers the triceps, and particularly dense as it approaches the outer and
inner condylar eminences of the humerus. It is pierced on the inner
side of the limb by the basilic vein, below the middle of the arm.
It is attached to the shaft and condylar eminences of the humerus by
the two processes next to be described.

The external and internal intermuscular septa are two fibrous
partitions which bind the aponeurosis of the arm to the humerus, and
with which the neighbouring muscles of the arm are intimately con-
nected. The external intermuscular septum extends upwards from the
outer condylar eminence along the outer lateral ridge to the insertion
of the deltoid, from which it receives tendinous fibres. It is pierced
from behind forwards by the musculo-spiral nerve and superior pro-
funda artery. The internal septum, much stronger, extends along the
ridge from the inner condylar eminence to the insertion of the coraco-
brachialis muscle. It is traversed from before backwards by the ulnar
nerve, and by the inferior profunda and anastomotic arteries.

At the bend of the elbow the aponeurosis is closely connected with
the periosteum covering the condylar eminences of the humerus and the
olecranon process of the ulna; and it is strengthened by tendinous
fibres sent from the triceps and biceps muscles.

Muscies.—The coraco-brachialis muscle, elongated in form, arises
from the tip of the coracoid process of the scapula, between the pector-
alis minor and the short head of the biceps, with which latter it is for a
short distance conjoined by an intermediate tendon. The lower part of
the muscle is directly inserted into the inner border of the humerus near
its middle, in a linear impression of from two to three inches in length,
between the origin of the triceps and the brachialis anticus. Higher
up its fibres are found inserted into a tendinous band which is prolonged
upwards to the head of the humerus, forming a sling over the latissimus
dorsi.

Felations.—This muscle is usually pierced by the musculo-cutaneous nerve ;
its outer border is in contact with the biceps muscle, and its inner with the
brachial artery, by which it is crossed obliquely near its insertion. It lies in
front of the tendons of the subscapularis, latissimus dorsi, and teres major, and
is covered by the deltoid and pectoralis major muscles.

Varieties.—This muscle has been shown by various authors to be subject to
considerable varieties, which seem to indicate, according to Wood, that it con-
sists typically of three parts ; viz., 1, a superior short one rising from the coracoid
process, or near it, and running over the capsular ligament, to be inserted close
below the small tuberosity of the humerus; 2, a second corresponding most
nearly to that usually described in human anatomy, of middle size, and placed
between the first and third ; 3, a third which is the longest and most superficially
placed, and descends to the inner condyle, or near it, and in many instances is

BICEPS FLEXOR CUBITI. 205

inserted into a supracondylar process. The middle division of the muscle is most
constant in man: but is generally accompanied by a part of the third; the
musculo-cutaneous nerve passing between them. The first and third constitute
the most marked varieties In man, and all three are found in various forms
and degrees of development in different animals. The internal brachial ligament
of Struthers is a fibrous band
connected with the inferior part
of this muscle. (John Wood,
on Hum. Muse. Variations, &c.,
Journ, of Anat. vol. i. p. 45.)

Fig. 172.—DrEP vinw oF THE
Muscuixzs or THE Ricut SHOUL-
DER AND ARM, FROM BEFORE.
(A. T.) 2

a, 6, outer half of the divided
clavicle ; c, coracoid process; d,
upper, ande, lower triangular space
left at the upper and lower angles
of the scapula on its anterior sur-
face to which the serratus magnus
is attached ; f, great tuberosity of
the humerus; y, surface of the
humerus below the bicipital
groove; h, outer, and 2, inner
condylar eminence of the humerus;
1, cut coracoid head, and 1’, cut
glenoid tendon of the biceps mus-
cle ; 2, folded tendon of insertion
of the pectoralis major, of which
one portion is seen running up to
the bicipital groove ; 3, lower cut
endof the deltoid ; 4, coraco-brachi-
alis; 5, subscapularis; 5’, its
insertion into the lesser tuberosity ;
6, teres major; 6’, its insertion
behind and below the latissimus
dorsi; 7, part of the latissimus
dorsi ; +, slip from the inferior
angle of the scapula ; 7’, insertion
of the tendon, after winding
round the teres major, in front of
and higher than that muscle ;
8, 8’, brachialis anticus ; 9, long
head of the triceps, at the upper
part seen in the interval between
the teres major and subscapularis
muscles ; 9’, inner head; 10,
flexor communis digitorum pro-
fundus ; 11, tendon of insertion of
the biceps.

The biceps flexor cubiti muscle has two heads of origin: one of
these, the internal or short head, arises conjointly with the coraco-
brachialis from the coracoid process of the scapula by a tendon which is
soon continued into muscle ; the other, the long head, arises by a
rounded tendon from the upper border of the glenoid fossa and glenoid
ligament, within the capsule of the shoulder-joint, and this tendon,
passing over the head of the humerus, leaves the joint by the bicipital
groove, gradually enlarging into the fleshy head as it descends. The
two muscular heads, lying side by side, then unite to form an elongated.
and thick belly, occupying the middle and lower part of the arm: a

206 MUSCLES OF THE UPPER LIMB.

little above the bend of the elbow, the muscle suddenly becomes
narrower, and is continued into the flat rounded tendon of insertion.
This tendon, slightly twisted upon itself as it descends, is inserted into
the rough posterior margin of the tuberosity of the radius, gliding on
the anterior smooth surface of that process by the intervention of a
synovial bursa. From the inner side of the lower part of the muscle
and tendon a strong flat aponeurotic band, called the semdlunar fascia,
passes downwards and inwards, and becomes blended with the deep
fascia of the forearm over the pronator radii teres.

Relations—Concealed above by the deltoid and pectoralis major muscles, the
biceps forms in the rest of its extent the prominence of the front of the arm. It
rests in its upper part on the humerus, and in its lower on the brachialis anticus,
and by its inner margin is in contact in its upper half with the coraco-brachialis,
in its lower with the brachial artery. Its inferior tendon is in contact with the
supinator brevis, and the fibrous expansion or semilunar fascia is stretched across
the brachial artery and median nerve.

Varieties—The biceps is one of the most variable muscles in the body. Among
the most frequent of its varieties are, 1st, the greater than usual separation of
its glenoid and coracoid portions, and 2nd, the increase in the number of its
heads of origin. The last occurs most frequently by a slip which forms a third head
arising from the humerus, in more or less close connection with the brachialis
anticus and the insertion of the coraco-brachialis, and being inserted into the
under surface of the semilunar fascia so as to form a tensor of that fascia: this
head lies generally on the outer side of the brachial artery, and has sometimes
been found covering it. A muscular band has also been observed extending
downwards from the biceps to the intermuscular septum over the inner condyle
of the humerus, and passing over the brachial artery. (R. Quain, ‘* The Anatomy
of the Arteries,” &c., p. 270, pl. 57.) A third head has also been observed passing
from the outside of the humerus (brachio-radialis of W. Gruber), and sometimes
from the bicipital groove, or great tuberosity. Occasionally the long head does
not reach the glenoid part of the bone, but stops short in the bicipital groove.

The brachialis anticus muscle arises from the lower half of the ante-
rior surface of the humerus. At the upper part of its origin it embraces
the insertion of the deltoid by two angular fleshy processes ; it extends
downwards to the capsule of the elbow-joint, and inwards to the internal
supracondylar ridge and the intermuscular septum in its whole extent ;
on its outer side it is separated from the external ridge and septum in the
greater part of its length by the supinator longus, and only arises from
it for a short distance at its upper end. It is closely adherent to the
ligament in front of the elbow-joint, and terminates below in a thick
mass which is inserted into the rough triangular surface on the front of
the coronoid process of the ulna.

Relations —This muscle lies immediately behind and projects at each side of
the biceps. It supports the brachial artery and median nerve. Fibres have
been found to pass inwards from it, over the brachial artery, to the internal in-
termuscular septum.

Varictics.—This muscle is subject to considerable variation. The most frequent
of these consist in its subdivision into two or sometimes more parts; its union
with neighbouring muscles, such as supinator longus, pronator teres or biceps ;
insertion of a slip from it into the semilunar fascia ; and occasionally into the
radius,

The triceps extensor cubiti muscle occupies tne whole posterior
brachial region. It consists superiorly of three portions or heads which
are united lower down in a common mass, the tendon of which is
inserted into the posterior and upper part of the olecranon, a bursa inter-

TRICEPS EXTENSOR AND ANCONEUS MUSCLES 207

vening between the tendon and the most prominent part of the process.
The middle or long head arises from the lower part of the glenoid cavity
and an adjoining rough portion of the outer border of the scapula, by a
tendon which spreads over the sides of the muscular structure proceed-
ing from it. This head forms the middle and superficial part of the
common mass, presenting a long flat tendon on its posterior surface
inferiorly. The external head takes origin by tendinous and fleshy
fibres along a line extending from the insertion of the teres minor,
downwards on the outer border of the humerus, as low as the musculo-
spiral groove, and from aa aponeurotic arch, formed by the external
intermuscular septum, as it crosses the upper part of the groove: its
fibres, which are comparatively short, descend obliquely to be inserted
into the tendon of the middle part. The internal or deep head, the
shortest of the three, arises from the whole posterior surface of the
humerus, beginning on the external aspect below the musculo-spiral
groove, and on the inner aspect of the arm reaching by a pointed process
as high as the insertion of the teres major: it also rises from the
internal intermuscular septum in all its length, and from the inferior
portion of the external septum. Some of its lower fibres are inserted
immediately into the olecranon, but the greater part of them join the
deep surface of the common tendon. No muscular fibres arise from
the musculo-spiral groove itself.

Relations.—The long head of the triceps lies between the two teres muscles
above, and is in contact with the capsule of the shoulder-joint. The musculo-
spiral nerve, and the superior profunda artery, are deeply imbedded in the muscle,
and in the musculo-spiral groove, pass between the inner and outer heads.

Varicties.—The most frequent varieties of the triceps muscles are the following,
viz. :—1, an additional or fourth head arising from the inner part of the humerus,
above or near the inner head; and 2, a slip of connection between the triceps
and the latissimus dorsi, corresponding with the dorsi-epitiochlearis or accessorius
tricipiti which is common among quadrumana, and exists in many other mam-
mals, The epitrochico-anconeus of Wenzel Gruber is a small muscle observed by
that author, Wood, and others, rising from behind the inner condyle, and inserted
into the olecranon.

Subanconeus.—On removing the triceps from the lower part of the humerus,
some muscular fibres will be found passing from that part of the bone to the
capsule of the elbow-joint. These fibres, which are analogous to the subcrureus
in the lower limb, have been described as distinct from the triceps under the
name subanconeus,.

The anconeus muscle, although placed chiefly below the elbow and
in the forearm, is intimately connected with the triceps, and may be most
appropriately associated in description with that muscle. It arises by
a narrow tendon from the extremity of the outer condylar eminence of
the humerus, at the posterior aspect. From this the fibres diverge
from one another, the upper being transverse, the rest passing down-
wards with increasing degrees of obliquity, and are inserted into the
olecranon on its radial aspect, and into the adjacent impression on the
upper third of the shaft of the ulna. Its superior fibres are parallel to
the lowest fibres of the internal head of the triceps, and are generally
in contact with them.

Relations.—This muscle is subcutaneous in its whole extent. Its deep surface
is in contact with the synovial membrane and external ligaments of the elbow-
joint.

Varicties.—The anconeus varies chiefly in being more or less united to the
triceps or the extensor carpi ulnaris,

208 MUSCLES OF THE UPPER LIMB.

Nerves of the Brachial Muscles.—The three anterior flexor muscles are all
supplied from the musculo-cutaneous nerve: the brachialis anticus, however,
receives also a small twig from the musculo-spiral nerve. The triceps and
anconeus receive their nerves entirely from the musculo-spiral.

Actions.—The biceps muscle raises the arm at the shoulder and flexes the
elbow-joint ; the short head of the biceps draws the arm inwards as well as up-
wards, as does also the coraco-brachialis. If the biceps be called into action
when the hand is in pronation, its first effect, from its insertion into the back
part of the tuberosity of the radius, is to produce supination of the forearm. The
biceps also makes tense the fascia of the forearm. The brachialis anticus is a
simple flexor of the elbow. The external and internal heads of the triceps and
the anconeus muscle. are simple extensors of the elbow joint; the long head,
while it assists extension, also tends to depress the arm on the scapula,

MUSCLES AND FASCI4 OF THE FOREARM,

' Fascia.—The superficial fascia of the forearm is most distinct
opposite the bend of the elbow, where the superficial veins contained
within its laminge are numerous and large. In the palm of the hand,
on the contrary, the subcutaneous tissue forms a firm connecting
medium between the skin and a strong aponeurosis named the palmar
fascia: it consists of a network of fibres passing between those two
structures, dividing the subcutaneous fat into small granular masses,
and preventing the skin from shifting to any considerable extent.

The aponeurosis of the forearm, like that of the arm, is composed
principally of circular fibres, strengthened, however, by longitudinal
and oblique fibres descending from the condylar eminences of the
humerus, from the olecranon, and from the semilunar fascia of the
biceps muscle. It is attached along the subcutaneous margin of the
ulna, and may be conveniently divided into an anterior and a posterior
part.

The anterior part of the aponeurosis of the forearm is much weaker
than the membrane on the posterior aspect of the limb. It is continued
below into the anterior annular ligament of the wrist. In the hollow im-
mediately below the bend of the elbow, it presents a small oval aperture
for the transmission of a short communicating branch between the super-
ficial and the deep veins of the forearm. It increases in density towards
the hand; and a little above the wrist affords a sheath to the tendon of
the long palmar muscle, which passes over the annular ligament to be
inserted into the narrow end of the palmar fascia. Several white lines
seen on the surface of the fascia mark the positions of the septa between
the origins of the muscles descending from the inner condylar eminence,
which are continuous with it. Between the superficial and the deep
flexor muscles, another layer of fascia is stretched from side to side; it
is stronger below than above, where it generally consists of little more
than thin connective tissue.

The anterior annular ligament of the carpus, previously described at
p. 157, is continuous at its upper margin with the fascia of the forearm,
and receives some fibres from the tendon of the flexor carpi ulnaris: the
lower margin is connected with a deep part of the palmar fascia, and
gives origin in part to most of the short muscles of the thumb and
little finger. This structure may be considered in some measure as a
deep thickened portion of the fascia of the wrist.

The posterior portion of the aponeurosis of the forearm, much thicker

PRONATOR RADII TERES. 209

than the anterior, is intimately connected with the strong septa between
the several superficial muscles, and sends off transversely a thin mem-
brane to separate the superficial from the deeper group of muscles.
Approaching the back of the wrist, the transverse fibres increase in
number and strength, and these, being stretched somewhat obliquely from
the outer margin of the radius on one side to the cuneiform and pisiform
bones and the palmar fascia on the other, constitute the posterior annular
ligament of the carpus. This structure is attached not only to the
points now indicated, but is likewise connected to the several longitu-
dinal ridges on the posterior surface of the radius, and thus converts
the intermediate grooves into fibro-osseous canals to lodge the tendons
of the extensor muscles. There are six separate spaces so enclosed,
and each is lined by a distinct synovial sac. The outermost space
corresponds with the groove on the outer side of the radius, and gives
passage to the extensores ossis metacarpi and primi internodii pollicis,
the next three, placed on the back of the radius, give passage respectively
to the two radial carpal extensors, the extensor secundi internodii
pollicis, and the common extensor of the fingers, with the extensor
indicis accompanying it ; between the radius and ulna is the compart-
ment for the extensor minimi digiti; and resting in the groove on the
back of the ulna is that for the extensor carpi ulnaris.

PRONATOR AND FLEXOR MUSCLES.

The eight muscles on the front and inner part of the fore arm are
disposed in two sets, five being superficial, the others more deeply
seated. :

The SUPERFICIAL LAYER of muscles comprehends the pronator radii
teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and flexor
digitorum sublimis. These five muscles are intimately united at their
origin from the inner condyle, to which they are attached by a common
tendon which gives fibres to each, and also sends septa between them.

The pronator radii teres muscle, the most external of the group,
arises by two distinct heads; one, large and superficial, is derived from
the upper part of the inner condylar eminence of the humerus, and from
the common tendon above mentioned; also from the fascia and the
inter-muscular septum of the forearm. The second head, a thin fasci-
culus deeply placed, comes from the inner margin of the coronoid pro-
cess, and joins the other at an acuteangle. ‘The fleshy belly thus formed
proceeds outwards and downwards, and ends in a flat tendon which
turns over the radius, and is inserted into a rough surface at the
middle of the outer side of that bone.

elations.—The pronator teres is placed superficially in the greater part of
its extent; but towards its insertion it is crossed by the radial artery and nerve,
and the supinator longus muscle. The ulnar border is in contact with the
flexor carpi radialis and palmaris longus: the radial border forms the inner
boundary of the angular space at the bend of the arm, in which are placed the
brachial artery, the median nerve, and the tendon of the biceps muscle, The
pronator teres covers the flexor sublimis digitorum; the ulnar artery passes
behind the whole muscle, and the median nerve between its two heads.

Varicties—The coronoid head is sometimes absent. In other cases the muscle
is prolonged further than usual by a slip rising from the intermuscular septum
above the inner condylar eminence of the humerus, or from the supracondylar
process when that is present. This peculiarity is sometimes associated with a

VOL, I. P

910 MUSCLES OF THE UPPER LIMB

change in the direction of the brachial artery. An additional head of origin
from the biceps or from the brachialis anticus has also been observed.

Fig. 173. Fig. 173.—Supnrrictan Musctes or THE Forrarm

AND Hann, SEEN From THE Front. (A. 7.) 2}

Ke ri

a 3, biceps flexor cubiti; 3’, its tendon of insertion ;
8", its aponeurotic slip; 4, brachialis anticus; 4’,
its inner and lower portion; 5’, lower part of the
triceps, seen arising from behind the intermuscular
septum; 6, pronator radii teres; 7, flexor carpi
radialis; 8, palmaris longus, passing at 8’ into the
palmar aponeurosis; 9, flexor carpi ulnaris; 10,
supinator longus ; between 10 and 38, +, supinator
brevis ; 11, extensor ossis metacarpi pollicis; 12,
extensor primi internodii ; 13, lower part of the flexor
digitorum sublimis ; 14, flexor longus pollicis; 15,
small part of the flexor digitorum profundus ; 16, pal-
maris brevis, lying on the muscles of the little finger ;
17, abductor pollicis.

The flexor carpi radialis muscle arises
from the inner condyle by the common ten-
don, from the fascia of the forearm, and from
the intermuscular septa placed between it
and the pronator teres on one side, the
palmaris longus on the other, and the flexor
sublimis posteriorly. ‘The fleshy fibres end
a little below the middle of the forearm
in a flat tendon, which occupies a special
compartment in the outer part of the
anterior annular ligament of the wrist, and
running through a groove in the os trape-
zium, to which it is bound by a thin fibrous
sheath lined by a synovial membrane, is
inserted into the base of the second meta-
carpal bone.

Felations—In the lower half of the forearm
the radial artery is placed to the outer side of the
tendon.

Varictics—At its origin this muscle has been
observed connected by an additional sip with the
tendon of the biceps or semilunar fascia, or with
the coronoid process of the ulna. Its insertion
has been found frequently displaced, as into
the trapezium, or into the third and even the
fourth metacarpal bone as well as the second.

The palmaris longus, the smallest muscle of this group, is placed
between the flexores carpi radialis and ulnaris, resting on the flexor
sublimis : it arises from the inner condyle and the intermuscular septa,
forming a small muscular belly, which soon ends in a long slender
tendon, inserted into the palmar fascia near the middle of the wrist,
and sometimes sending a slip to the short muscles of the thumb.

Varicties—This is one of the most variable muscles in the body. It is wanting
to the extent of about ten per cent. of the bodies examined. It is subject to
many variations of form; ¢.g., the muscular fibres may occupy the middle of the
muscle, which then commences and ends by an elongated tendon ; or the mus-

FLEXOR DIGITORUM SUBLIMIS “11

eular structure may be placed towards the lower end, the upper part being
tendinous. Occasionally there are two long palmar muscles, one having the
ordinary shape, while the other has one of the forms above referred to. Ocea-
sionally its origin passes up to the triceps muscle. Its insertion below is also
subject to great variation. The most remarkable peculiarity is that in which a
small muscle, a second palmaris longus, placed nearer to the inner border of the
forearm than the usual muscle, covers the ulnar artery for some space above the
carpus, and terminates sometimes in the annular ligament or in the fascia, and
frequently in the short muscles of the little finger.

The flexor carpi ulnaris, the innermost muscle of the superficial
group, arises by two heads, one of which is attached tendinously to the
inner condylar eminence of the humerus, the other to the inner side of
the olecranon, and to the posterior border of the ulnar for two-thirds of
its length, by an aponeurosis which is inseparably connected with the
investing aponcurosis of the limb. The muscular fibres descending
from this long line of origin, terminate in a tendon, which descends
along the anterior margin of the muscle, and is inserted into the pisi-
form bone: this tendon is prolonged, by means of ligamentous struc-
tures, to the fifth metacarpal and unciform bones, as well as to the
annular ligament and muscles of the little finger.

Relations—This muscle rests on the flexor profundus digitorum. The ulnar
nerve passes down into the forearm in the interval between the two heads, and is
then covered by the muscle ; for the middle part of its course the ulnar artery is
also covered by it, and in the lower part of the forearm, the nerve and artery,
emerging from behind the muscle, lie on its radial side. The posterior ulnar
recurrent artery passes between its two heads of origin.

The flexor digitorum sublimis vel perforatus, the superficial
flexor of the fingers, is a broad flat muscle placed behind the preceding
muscles. It arises from the inner condyle by the common tendon, and
the fibrous septa common to it and the other muscles; from the internal
lateral ligament ; from the anterior surface of the coronoid process at
the inner side ; and by a thin flat portion from the oblique line and
part of the anterior border of the radius. It is divided inferiorly into
four tendons, which pass to be inserted into the second phalanx of each
of the four inner digits. These tendons pass under the annular liga-
ment of the wrist in pairs, one in front of the other ; the anterior pair
consistisg of those for the middle and ring fingers, the posterior of
those for the index and little fingers. That for the little finger is
smaller than the others.

In the palm of the hand the tendons diverge, and each, accompanied
by a tendon of the flexor profundus, enters a fibrous sheath which binds
both tendons down to the palmar surface of the phalanges. Opposite
the first phalanx the tendon of the flexor sublimis divides into two parts,
which fold closely round the tendon of the deep flexor, and are reunited
by their margins behind it: the two portions of the tendon thereafter
separating, pass to be inserted one on each side into a ridge at the
middle of the lateral border of the second phalanx. A large synovial
bursa loosely invests the tendons of both the superficial and deep flexors
of the fingers behind the annular ligament, extending downwards into
the palm of the hand. In the little finger it approaches the synovial
lining of the sheath, and in the thumb it usually communicates
with it.

The sheaths of the flexor tendons, by which they are bound down to

P 2

212 MUSCLES OF THE UPPER LIMB.

the fingers, are formed opposite the first and second phalanges by strong
tendinous bands of transverse fibres (ligamenta vaginalia) attached to
the rough margins of the palmar surfaces of the phalanges. Opposite
the joints, flexion is secured by the substitution for those bands of a
thin membrane, strengthened by oblique decussating fibres. The tendi
nous sheath has a synovial lining, which is simple in front, but poste-

Fig. 174.

Fig. 174.—Bones or Two Fincurs, WITH THE INSERTIONS OF THE TENDONS. 4%

In A, the tendons of the flexor muscles are bound to the finger by the fibrous sheaths.
In B, the bands have been removed, as well as the synovial capsules and vincula acces-
soria ; 1, metacarpal bone ; 2, tendon of the flexor sublimis ; 3, tendon of the flexor
profundus ; *, perforation of the sublimis by the profundus tendon ; 4, tendon of the
extensor digitorum communis; 5, one of the lumbricales muscles ; 6, one of the inter-
osseous muscles.

riorly dips between the tendons. A few slender and loose bands
(vincula accessoria tendinum) extend from the floor of the sheath to
the deep surface of both tendons. Behind each tendon, near its inser-
tion, is a short membranous structure (ligamentum breve) which fixes
the tendon to the front of the phalanx situated above that into which
it is inserted.

Relations.—Superiorly, the flexor sublimis is concealed by the other muscles
of the superficial set, and is crossed near its radial origin by the radial artery ;
it rests on the flexor pollicis longus and flexor profundus, separated from the
latter by the median nerve and the ulnar artery. In the palm of the hand, its
tendons are covered by the palmar fascia, the superficial palmar arterial arch, and
the branches of the median nerve; and they lie in front of the accompanying
tendons of the flexor profundus.

Varicties—The radial origin of the flexor sublimis is sometimes wanting.
The body of the muscle is occasionally subdivided, so that each of the four
tendons has a distinct muscular beliy : this happens most frequently with the
radial and the little finger part. The tendon to the little finger has been observed
to be absent.

In connection with this muscle may be mentioned an additional small muscle,
the vadio-carpalis, which has been seen by many anatomists, rising from the outer
border of the radius usually above the pronator quadratus, and very variably
inserted below, into the trapezium magnum, or some other part of the carpus ;
and in other cases into one or other of the metacarpal bones.

A muscular slip is frequently given from this muscle to the flexor profundus,
or to the flexor longus pollicis.

The DEEP-SEATED MUSCLES, on the anterior surface of the forearm,
are the flexor profundus, flexor pollicis longus, and pronator quadratus.

FLEXOR PROFUNDUS. LUMBRICALES. 213

The flexor profundus digitorum, or flexor perforans, a large and
thick muscle, arises from the hollow at the inner side of the olecranon ;
from the inner and anterior surfaces of the ulna for three-fourths of its
length ; from the ulnar half of the inter-
osseous ligament for the same distance ; Fig. 175.
and from the aponeurosis attaching the
flexor carpi ulnaris to the ulna. It divides
inferiorly into four tendons, only one of
which, that for the index finger, is distinct
from the others above the wrist—the rest
being connected together as far as the palm.
In the palm the tendons, as they diverge,
give origin to the lumbricales muscles.
In front of the fingers they are bound to
the first and second phalanges in the
sheath common to them with the per-
forated tendons by the vaginal ligaments.
Opposite the first phalanx, the tendon of
each finger passes through the opening
formed for its transmission in the tendon
of the flexor sublimis, and is inserted into
the base of the last phalanx.

Fig. 175.—Derrrp AntErtor Muscurs oF THE
Forzarm. (A. 7.) §

The superficial muscles of the forearm and hand,
together with the lumbricales, have been removed,
and the place of the anterior annular ligament of the
carpus is marked by two dotted lines. «@, surface of
the humerus above the coronoid fossa ; 6, rough sur-
face of the ulna, into which the brachialis anticus is
inserted ; c, head of the radius covered by the orbicu-
lar ligament, and between this and a, the anterior
ligament of the elbow-joint; +, the internal lateral
ligament ; d, the lower end of the radius; e¢, that of
the ulna; jf, the scaphoid and trapezium bones; 1,
supinator radii brevis; 2, flexor longus pollicis ; 3,
flexor digitorum profundus; 3’, its four tendons,
where they are about to pass under the annular liga-
ment; 4, pronator quadratus on the lower part of the
radius; 5, deep head of flexor brevis pollicis ; 6, ad-
ductor pollicis; 7, first dorsal interosseous muscle ;
8, in the second space, is placed between the first
palmar and the second dorsal interosseous muscles ;
in the third space, between the third dorsal and the
second palmar; in the fourth space, between the
fourth dorsal and the third palmar. (For the lumbri-
cales muscles, see Figs. 174 and 180.)

Relations.—The upper extremity of this muscle embraces the insertion of the
brachialis anticus. On its surface lie the median nerve and the ulnar artery and
nerve. The external border is parallel with the flexor longus pollicis, from which
it is separated, on the interosseous membrane, by the anterior interosseous vessels
and nerve. The tendons are covered by the synovial sacs, which have been men-
tioned in connection with the flexor sublimis,

The lumbricales muscles are four tapering fleshy fasciculi, passing
from the tendons of the flexor profundus to the first digital phalanges.
Hach muscle rises by fleshy fibres from the outer or radial border of one

214 MUSCLES OF THE UPPER LIMB.

of the deep flexor tendons, and in the case of the two inner muscles also
from the ulnar border of the second and third, and proceeding forwards
to the radial sides of the fingers, each is inserted into an expansion of
the extensor tendon on the dorsal aspect of the metacarpal phalanx ot
the finger.

Varicties.—The flexor profundus often presents varieties in its origin, deriving
fibres from the radius in some instances, a distinct slip from the coronoid process
of the ulnar in others, and more rarely from the inner condyle of the humerus.
It is not unfrequently connected with the flexor sublimis, or with the flexor
longus pollicis. The distinct slip from the coronoid process constitutes in nume-
rous cases an accessory or supplemental muscle which joins very variously one or
more of the perforating tendons.

The varieties of the lumbricales muscles are of frequent occurrence. Their
number is sometimes diminished to three, and in rare instances is increased to five
or six. The destination of cne or two of them is often changed, and one finger
(most frequently the third or fourth) has sometimes two inserted into it. Lastly,
one muscle may be inserted into two fingers. The fourth has been observed to
take the place of the fourth perforating tendon of the flexor profundus,

The flexor longus pollicis muscle, placed side by side with the flexor
profundus digitorum, arises from the anterior grooved surface of the
radius from the oblique line to the edge of the pronator quadratus ;
it arises also from the adjacent part of the interosseous ligament, and
sometimes by a rounded fleshy and tendinous slip, distinct from the rest
of the muscle, from the inner part of the coronoid process. The muscle
ends in a tendon which passes behind the annular ligament of the wrist
close to the trapezium, turns outwards between the two heads of the
flexor brevis and between the sesamoid bones, and, entering a canal
similar to those of the other flexor tendons, is finally inserted into the
base of the second phalanx of the thumb

Varicties—A very common variety in this muscle (in two-fifths of subjects
dissected by Macalister) is the existence of a second or accessory tendon for the
thumb : this may arise from the flexor sublimis, the coronoid process, or some-
times as far up as the internal condyle. The flexor longus pollicis is also some-
times connected by a slip with the flexor sublimis or profundus, or the pronator
teres. A tendon of insertion into the index finger has also been observed.

The pronator quadratus, placed close to the bones behind the last
two muscles, arises from the anterior and inner surfaces of the ulnar
for about two inches above its carpal extremity; its fibres cross the
lower part of the forearm, some transversely and others obliquely,
and they are inserted for an equal distance into the fore part of the
radius.

Varietics—The pronator quadratus is subject to varieties, chiefly as follows :—
1, It may be entirely absent, but this is rare; 2, it is subdivided into two layers,
or occasionally into three; 3, it extends farther upwards on the bones of the
forearm than usual ; 4, it is prolonged downwards on the carpus, in some cases
as a radio-carpal, and in others as an ulno-carpal muscle (Macalister, Journ. of
Anat., vol. v., W. Griiber, loc. cit.).

Nerves.—The muscles of the pronator and flexor group receive their nerves
in great part from the median ; only one muscle being wholly supplied from the
ulnar nerve. The branches from the median are distributed to the muscles in
two groups, one to the superficial and another to the deep set. From these the
anterior interosseous is a distinct branch, which accompanies the anterior inter-
osseous vessels in Tront of the imterosseous ligament, and ends in the pronator

SUPINATOR RADII LONGUS. 215

quadratus. Only one half of the flexor profundus digitorum is supplied with
nerves from the median, the other half, together with the whole of the flexor
carpi ulnaris receives twigs from the ulnar nerve.

SUPINATOR AND EXTENSOR MUSCLES.

The muscles of this group are, like those of the front of the forearm,
divided into a superficial and a deep layer.

The SUPERFICIAL MUSCLES are six In num-
ber, viz., the supinator longus, the exten-
sores carpi radiales longior and brevior,
the extensor communis digitorum, extensor
minimi digiti, and extensor carpi ulnaris.

The supinator radii longus muscle
arises from the upper two-thirds of the ex-
ternal ridge of the humerus, and the ex-
ternal inter-muscular septum. Its fibres
form a thin fleshy mass which descends
upon the anterior and outer border of the
forearm, about the middle of which they
end in a flat tendon, which is inserted
into the external border of the radius, near
the base of the styloid process.

Fig. 176.—Suprrrictan Muscies oF THE ForrARM
AND HAND, SEEN FROM BEHIND. (A.T.) 3
d, olecranon; e, external condylar eminence; jf,
lower end of the ulnar; 8, main tendon of the triceps
extensor cubiti ; 8”, its inner head ; 9, anconeus; 10,
part of brachialis anticus ; 11, supinator longus; 12,
extensor carpi radialis longior; 13, -—— brevior ;
14, extensor communis digitorum ; 15, extensor carpi
ulnaris ; 15’, its insertion into the fifth metacarpal
bone; +, between 14 and 15, extensor minimi
digiti ; 16, origin of the flexor carpi ulnaris by an
aponeurosis from the back of the ulna; 17, extensor
ossis metacarpi pollicis: 17’, its insertion into the
first metacarpal bone ; 18, extensor primi internodii
pollicis ; 18’, its insertion into the first phalanx ; +
and +, posterior annular ligament of the carpus or
retinaculum of the extensor tendons ; at {, the ten-
dons ‘of the long and short radial extensors; at +,
the tendon of the extensor minimi digiti; 19, tendon
of the extensor secundi internodii ; 20, is placed on
the proximal end of the second metacarpal bone, close
to the insertion of the radial extensors of the carpus :
in the hand, the dorsal interossei muscles are shown,
and on the middle finger the insertion of the exten-
sor tendons.

Fclations—This muscle is covered only by
skin and fascia, except at its insertion, where
two of the extensor tendons of the thumb lie
superficial to it. Above, the brachialis anticus is
in contact with its inner surface and the radial extensors of the carpus are
beneath it. It forms the outer boundary of the triangular space at the bend of the
elbow, and in the forearm it rests upon the supinator brevis, flexor sublimis
digitorum, pronator teres, radial artery, musculo-spiral and radial nerves.

Varicties—These are neither great nor numerous in this muscle. One of the

216 MUSCLES OF THE UPPER LIMB.

commonest is the division of the tendon or lower part of the muscle into two
or sometimes three slips, which are inserted either together or at some distance
from each other. The supinator longus may also be connected to some of the
neighbouring muscles, especially at its origin.

The extensor carpi radialis longior muscle arises from the lower
part of the external condylar ridge of the humerus, and from the inter-
muscular septum. Its muscular belly ends at the meeting of the upper
and middle thirds of the forearm in a flat tendon, which passes, con-
jointly with that of the following muscle, over the lower end of the
radius in the outermost of the two broad grooves on the posterior
surface of that bone, and is inserted into the base of the second
metacarpal bone. A small bursa lies beneath the tendon at its insertion.

The extensor carpi radialis brevior muscle arises from the outer
condylar eminence of the humerus by a tendon common to it and
the other extensor muscles, from the intervening fibrous septa, from a
superficial tendinous expansion, and from the external lateral ligament
of the elbow-joint. Its muscular belly ends in a flat tendon, which
descends with that of the extensor longior, passes through the same
eroove of the radius with it, and is inserted into the base of the meta-
carpal bone of the middle finger. A bursa is placed between this
muscle and the supinator brevis, and a smaller one between the tendon
and the metacarpal bone.

Relations —Of the two foregoing muscles the extensor longus is the most
superficial. The extensor brevis covers the supinator brevis and the insertion of
the pronator radii teres. The tendons of these muscles and that of the supinator
longus are crossed obliquely by the extensors of the metacarpal bone and first
phalanx of the thumb.

Varictics.—The two foregoing muscles are subject to a similar variation in
being, one or other of them, split up into two or sometimes three tendons pre-
vious to insertion; the tendons of either muscle being inserted into both the
second and third metacarpal bones: occasionally a slip passes also to the fourth
metacarpal bone.

An additional muscle, called extensor carpi radialis accessorius by Mr. Wood, is
of frequent occurrence, rising from the radius below the extensor carpi radialis
longior, and running through the same groove behind the radius at the wrist, it
is inserted most frequently into the metacarpal bone of the thumb, but sometimes
into the abductor pollicis, first dorsal interosseous muscle or other part.

The extensor communis digitorum muscle, placed between the
extensor carpi radialis brevior and the extensor minimi digiti, arises from
the outer condylar eminence by a tendon common to it and the other
superficial extensor muscles, also from the fascia of the forearm, and the
septa between it and the adjoining muscles. Somewhat below the middle
of the forearm the muscular part ends in four tendons, which pass between
the posterior annular ligament of the wrist and the innermost broad
groove on the back of the radius, and diverge as they proceed along
the carpus and metacarpus to reach the fingers. Here each is increased
by tendinous fibres derived from the lumbricales and interosseous
muscles forming a fibrous expansion, which covers the back of the first
and second digital phalanges, and terminates upon the third phalanx.
It is attached to the second and third phalanges in the following
manner. Opposite the first bone the tendon divides into three fasci-
culi; the central one is much thinner than the others, and is inserted
into the base of the second phalanx ; the two lateral parts, continuing

EXTENSOR COMMUNIS DIGITORUM. 217

onwards, are joined together towards the middle or fore part of the second
phalanx, and, having passed beyond this, are inserted into the last pha-
lanx. On the index and little fingers the tendons are joined before their
division, by the special extensor tendons of those digits.

. ro ; Fie
Fig. 177.—Derrp Postmrior Muscies oF THE Fig. 177.
Forrarm. (A. T.) 1

a, posterior surface of the humerus ; 6, ole- |
eranon ; c, radius; @, lower part of the ulnar,
grooved for the tendon of the extensor carpi ulnaris ;
¢, base of the second metacarpal bone ; 1, anconeus ;
2, flexor digitorum profundus, exposed by the re-
moval of the aponeurotic tendon of 3, the flexor
carpi ulnaris ; +, supinator brevis; 4, extensor
carpi radialis brevior, and 5, the cut tendon of the
extensor carpi radialis longior ; e, their insertion
into the second and third metacarpal bones; 6,
extensor ossis metacarpi pollicis ; 6’, its insertion
into the first metacarpal bone ; 7, extensor primi
internodii pollicis ; 7’, its insertion into the base of
the first phalanx ; 8, extensor secundi internodii
pollicis ; 8’, its insertion into the base of the last
phalanx ; 9, extensor indicis ; 9’, its junction with
the tendon of the common extensor, which is cut
short: in the metacarpal spaces the four dorsal
interossel muscles are represented, the tendons of
the common extensor having been removed ; and at
10, the insertion of the second and third dorsal
interossei, by a triangular expansion, into the tendon
of the extensor communis, as well as the mode of
insertion of that tendon into the middle and last
phalanges, are shown.

On the back of the hand the tendon of
the ring-finger gives off two processes,
one on each side, the lateral vincula,
which pass obliquely downwards to join
the tendons of the middle and little
fingers : in consequence of this arrange-
ment it follows that, if those two fingers
be flexed, the tendon of the ring-finger
is held downwards, and it becomes impos-
sible to extend that finger by the action
of the muscle. The tendon of the index-
finger is only united to that of the
middle finger by a loose transverse, semi-
transparent band of fibres, and is free in
its action. A synovial membrane invests
the tendons of this muscle as they pass
under the annular ligament.

Varieties.—The varieties of the extensor communis digitorum resolve them-
selves chiefly into the following, viz., 1st, the occasional deficiency of one or
more of the tendons of insertion, and, 2nd, more frequently an increase in their
number. This last goes in some instances to the extent of doubling the tendon.
to each of the fingers, and even to tripling it to one or two of them. More
frequently, however, the increase of number of the tendons is limited to the
index or little finger alone. The muscular substance is also liable to be divided
more deeply than usual into distinct portions for a part or the whole of its length.

218 MUSCLES OF THE UPPER LIMB.

The extensor minimi digiti is a slender muscle which is placed
between the extensor communis digitorum and the extensor carpi
ulnaris, and arises by means of a thin tendon in common with the ex-
tensor communis. ‘The tendon in which it ends occupies a groove
between the radius and ulna, passing through a special compartment
in the annular ligament, and joins the fourth digital tendon of the
common extensor.

Varicties.—This muscle, like that preceding, and the same occurs in the indi-
cator muscle afterwards described, is subject to an increase in the number of its
tendons of insertion, and in a large proportion of the cases the additional
tendon is inserted into the ring-finger. The entire absence of the muscle has
also been observed. In the case of the indicator, the additional tendon is most
frequently inserted into the middle finger, constituting the extensor medii, which
is sometimes separate in the whole length of the muscle.

The extensor carpi ulnaris, the most internal of the muscies
descending on the back of the forearm, arises from the external con-
dylar eminence of the humerus by the common tendon and prolongation
of that structure ; from the posterior border of the ulna, below the
anconeus, for about the middle third ; and from the fascia of the fore-
arm. The muscular fibres derived from these sources incline somewhat
inwards, and end in a tendon, which runs through a special groove in
the carpal end of the ulna and a separate sheath in the annular ligament,
and is inserted into the base of the metacarpal bone of the little finger
on its posterior aspect.

Varieties —This muscle is frequently connected with the skort abductor minimi
digiti. It also sometimes sends a prolongation to the extensor tendons on the
back of the little finger, which has been named ulnaris quinti.

The DEEP-SEATED MUSCLES on the back of the forearm are five in
number, the supinator brevis, the three extensors of the thumb, and the
extensor of the index-finger.

The supinator radii brevis muscle arises from the external lateral
ligament of the elbow-joint, and from the annular ligament of the radius ;
alyo from a rough depression below the sigmoid cavity of the ulna, and
from the outer border of that bone for two inches. The fibres of the
muscle, derived from these points of attachment, as well as from a
tendinous expansion on the surface, pass obliquely round the upper
part of the radius, covering it closely except at the inner side, and are
inserted into that bone for rather more than a third of its length,
passing down to the upper margin of the insertioh of the pronator
teres. It is pierced by the posterior interosseous nerve.

Varietics.—This muscle is subject to more or less division at the place of
passage of the posterior interosseous nerve, and occasionally the insertion of an
accessory slip takes place into the biceps tendon or tuberosity of the radius. A
set of short fibres passing round the upper part of the radius has received the
name of tensor ligamenti orbicularis anterior (W. Griiber, Cruveilhier).

The extensor ossis metacarpi pollicis muscle (abductor longus
pollicis,—Alb.) arises from an elongated depression on the radial side
of the posterior surface of the ulna below the origin of the supinator
brevis, from a similar extent of surface of the radius below the insertion
of the same muscle, and from the interosseous membrane between.
Thence descending obliquely outwards, it ends in a tendon, which
passes, in company with the extensor primi internodii pollicis, through

EXTENSOR MUSCLES OF THE THUMB. 219

the groove on the outer border of the lower extremity of the radius,
and is inserted in the base of the metacarpal bone of the thumb.

Relations —The upper part of this muscle is concealed by the common
extensor, but it becomes superficial beneath, and together with the next muscle
crosses the tendons of the radial extensors of the carpus, conceals the insertion
of the supinator longus, and, beneath the extremity of the radius, crosses the
radial artery.

The extensor primi internodii pollicis muscle lies close to the
lower border of the extensor ossis metacarpi, and is much smaller than
that muscle ; it drises from the interosseous ligament and the radius near
the middle of the forearm ; its tendon accompanies that of the extensor
ossis metacarpi through the same compartment of the annular liga-
men , and passes on to be inserted into the proximal end of the first
phalanx.

The extensor secundi internodii pollicis muscle, much larger than
the extensor primi internodii, which it overlaps, arises immediately below
the extensor ossis metacarpi from the shaft of the ulna for two or three
inche and from the interosseous ligament at its lower end for about

Fig. 178.—Suprrrictan Mus- Fig. 178
CLES AND TENDONS ON THE
Back OF THE WRIST AND
Hanp (after Bourgery). 4
The posterior annular liga-

ment of the wrist is represented.
1, extensor ossis metacarpi pol-
licis; 1’, its insertion; 2, ex-
tensor primi internodii pollicis 5
2’, its insertion ; 3, 3’, tendon
of the extensor secundi inter-
nodii pollicis ; 4, extensor com-
munis digitorum ; 4’, tendon to
the middle finger, receiving the
insertion of the second and third
dorsal interossei ; 4", division of
the tendon into three portions,
of which the median is inserted
into the second phalanx, the two
lateral passing on to be inserted
into the terminal phalanx ; the
union of the tendons of the
third, fourth, and fifth fingers
is shown; 5, extensor minimi
digiti ; 5’, its junction with the
slip of the common extensor ;
6, placed on the lower end of
the ulna, points to the extensor
carpi ulnaris; 6’, insertion of
this muscle into the base of the
fifth metacarpal bone ; 7, part
of the flexor carpi ulnaris; 8,
placed on the os magnum, points
to the insertion of the extensor
carpi radialis brevior ; 8’, placed
on the base of the second metacarpal bone, points to the insertion of the extensor carpi
radialis longior; 9, tendon of the extensor indicis; 10, small part of the adductor
pollicis, and deep head of the flexor brevis pollicis ; 11, first dorsal interosseous or
abductor indicis : in the other three interosseous spaces are seen in succession, from the
radial side inwards, the insertion of the first palmar, second dorsal, third dorsal, second
palmar, fourth dorsal, and third palmar interossei muscles ; 12, abductor minimi digiti.

220 MUSCLES OF THE UPPER LIMB.

an incn. Its fibres end in a tendon, which occupies the narrow oblique
groove in the middle of the posterior surface of the carpal end of the
radius, and is bound down in a separate compartment of the annular liga-
ment ; it is inserted into the base of the terminal phalanx of the thumb.

Relations—The groove which lodges the radial extensors of the carpus inter-
venes between those which lodge the tendon of this muscle and the tendons of
the other extensors of the thumb.

Varicties—The extensor muscles of the thumb are subject to considerable
variations, and if all the three muscles be included they seem to occur as often
as in one out of every six subjects dissected. The most common occur in the
extensor ossis metacarpi, and consist in more or less cleavage of the muscle or its
tendon into separate parts. The insertion of the distinct tendons takes place
either doubly into the first metacarpal bone, or in part into the trapezium, or
into the abductor or opponens pollicis muscles. The extensor primi internodii is
sometimes absent, being, as it were, fused with the extensor ossis metacarpi, in
other cases it is more or less united with the extensor secundi internodii pollicis.
A frequent variety, representing a muscle normally existing in the dog and many
carnivora, is formed by the interposition of an additional extensor between the
indicator and the extensor secundi internodii pollicis, with a double tendon and
insertion into both fingers.

The extensor indicis or indicator muscle arises from the lower end
of the posterior surface of the ulna for three or four inches. The
tendon passes with the common extensor through a compartment of the
annular ligament, comes in contact with the tendon from that muscle
destined for the index-finger, and unites with it to form the expansion
already described.

Fig. 179.—Transverse Secrion oF THE Rigut
HAND BETWEEN THE CaRPUS AND MeEtTA-
carpus. (A. 7.) 3

a, 6, c, d, e, articular surfaces of the trape-
zium, trapezoid, and unciform bones ; a’, palmar
ridge of the trapezium ; ¢, unciform process ;
between a’ and ¢e, the cut edge of the annular
ligament, a process tdwards the trapezium at
11, by which the tendon of the flexor carpi
radialis is eaclosed in the groove of the trape-
zium ; 1, tendon of the extensor ossis metacarpi
pollicis ; 2, extensor primi internodii; 3, ex-
tensor secundi internodii; 4, extensor indicis ;
5 and 6, long and short radial extensors of the carpus ; 7, the four divisions of the tendon
of the common extensor of the fingers; 8, extensor minimi digiti ; 9, extensor carpi
ulnaris ; 10, flexor carpi radialis ; 11, flexor longus pollicis ; 12, the first on the ulnar
side of the tendons of the flexor sublimis digitorum ; 13, the same of the flexor pro-
fundus ; 14, the median nerve ; 15, the palmar aponeurosis stretched across the annular
ligament ; 16, palmaris brevis; 17, muscles of the ball of the thumb; 18, muscles of
the little finger.

Vavicties.—A short additional extensor of one or more of the fingers has been
observed as an occasional variety by various anatomists since Albinus, and who
named it extensor brevis in the case of the index-finger with which it is most
frequently connected. But it appears from later observations to vary consider-
ably both in its origin, which may be from the radius or from a carpal or meta-
carpal bone, and in its insertion which may be into only one or into two or
more of the fingers; thus forming an extensor brevis digitorum.

Nerves.—The anconeus,supinator longus,and extensor carpi radialis longior
receive branches directly from the musculo-spiral nerve ; the short radial extensor,
the ulnar extensor of the carpus. and the common extensor of the fingers, with
that of the little finger, are supplied from the radial division, while the supinator

|

MUSCLES OF THE HAND. 221

brevis and the four deeper extensor muscles receive branches from the interosseous
nerve.

MUSCLES OF THE HAND.

Besides the tendons of the long muscles and the lumbricales already
described, there are placed in the hand one superficial muscle called
palmaris brevis, the short muscles
of the thumb and little finger, and Fig. 180.
the interossei muscles.

Fig. 180.—Musctrs anp TENDONS OF THE

Paumar Aspect or THE Hanp. 4}

Portions of the tendons of the superficial
flexor have been cut away to show those of
the deep flexor and the lumbricales. 1, ten-
don of the flexor carpi radialis, cut short ; 2,
tendon of the flexor carpi ulnaris, inserted
into the pisiform bone ; 3, anterior annular
ligament of the carpus ; 4, abductor pollicis ;
5, opponens pollicis ; 6, 6, flexor brevis ; 7,
adductor pollicis ; 8, abductor minimi digiti ;
9, flexor brevis minimi digiti; 10, lum-
bricales, passing to their insertion on the
radial side of the four fingers.

The palmaris brevis is a thin flat
subcutaneous muscle, which arises
from the inner margin of the palmar
fascia and annular ligament ; its
fibres proceed transversely inwards,
and are inserted into the skin along
the inner border of the palm.

Relations—The palmaris brevis crosses
the muscles of the little finger and covers
the ulnar artery and nerve. It is subject
to considerable variation in its breadth
and thickness, consisting sometimes of
only a few scattered fibres.

Fig. 181.—Drrp Mvusc.es oF THE PALM or
tHE Hanp. 2
The abductor pollicis and abductor minimi
digiti, together with the anterior annular
ligament and the long flexor tendons in the
palm have been removed; in the fore-finger
the tendons of both the superficial and deep
flexors remain; in the other fingers the ten-
dons of the superficial flexor have been
removed. 1, pronator quadratus muscle ;
2, opponens pollicis; 3, flexor brevis pollicis ;
4, adductor pollicis; 5, opponens minimi
digiti; 6, unciform bone; 7, 8, interosseous
muscles.

Muscizs or THE THumB.—The fleshy mass which forms the thenar
eminence, or ball of the thumb, consists of four muscles.

The abductor pollicis muscle (abductor brevis pollicis,—Alb.), super-
ficial and flat, arises from the annular ligament and from the ridge of
the os trapezium, and proceeding outwards and forwards, is inserted

922 MUSCLES OF THE UPPER LIMB.

by a tendon into the radial border of the first phalanx of the thumb
ab its base.

The opponens pollicis muscle, placed behind the abductor, arises
from the annular ligament and from the os trapezium and its ridge,
and is inserted into the whole length of the metacarpal bone of the
thumb at the radial border.

The flexor brevis pollicis muscle arises by two heads, a superficial
and a deep. The superficial head is attached to the outer two-thirds of
the annular ligament and to the trapezium : the deep head is attached
to the os trapezoides and os magnum, to the sheath of the flexor carpi
radialis, and to the sheath of the flexor carpi radialis, and to the bases of
the second and third metacarpal bones. From the superficial and deep
heads of origin two strong masses of fibres proceed, which, becoming
tendinons, are inserted into the sides of the base of the first phalanx of
the thumb ; the outer head is also joined by a considerable fasciculus
from the deeper origin ; the inner head is inserted conjointly with the
adductor pollicis. In each of the tendons of insertion a sesamoid bone
is developed, which plays over the grooved surface of the first meta-
carpal bone. The tendon of the long flexor les between the heads of
origin, and grooves the surface of the muscle as it passes between the
tendons of insertion.

The adductor pollicis muscle arises from the middle two-thirds of
the palmar surface of the third metacarpal bone, and is inserted into
the base of the first phalanx of the thuinb along with the inner tendon
of the short flexor.

MUSCLES OF THE LITTLE FINGER.—The fleshy mass at the inner
border of the hand (hypothenar eminence) consists of three muscles
passing to the little finger.

The abductor minimi digiti muscle arises by tendinous fibres from
the pisiform bone and the inserted tendon of the flexor carpi ulnaris,
and is inserted into the base of the first phalanx of the little finger
ou the ulnar border.

The flexor brevis minimi digiti, separated at its origin from the ab-
ductor muscle by a small interval through which pass the deep palmar
branch of the ulnar nerve and the communicating branch of the ulnar
artery, arises from the front of the annular ligament, and from a tip of
the hooked process of the unciform bone, and is inserted into the base
of the first phalanx of the little finger, in connection with the preceding
muscle. This muscle is sometimes absent, or becomes incorporated with
the abductor.

The opponens minimi digiti muscle arises from the annular ligament
and the unciform process, and is inserted into the ulnar border of the
fiith metacarpal bone in all its length.

The INTEROSSEOUS MUSCLES occupy the intervals between the meta-
carpal bones. ‘They are seven in number, all of them more or less
visible from the palmar aspect, and they are divided into two sets, Viz..
those which are best seen on the dorsal aspect of the metacarpus, and
those which are seen only in the palm. Their disposition is most easily
understood by reference to their action.

The dorsal interossei muscles withdraw the fingers from the'middle
line of the hand ; they are four in number, each occupying one of the
spaces between the metacarpal bones, and are numbered from with-
out inwards. Each muscle arises from both the metacarpal bones

INTEROSSEOUS MUSCLES. 223

between which it is placed, but most extensively from that support-
ing the finger upon which it acts, and the fibres converge pennately

Fig. 182. Fig. 183.

Fig. 182.—Tue Ricut HAND FROM BEHIND, SHOWING THE DoRsAL INTEROSSEOUS
Muscirs. ?

7

The tendons of the extensor muscles have been removed as far as the distal ends
of the metacarpal bones. 1, 2, 3, and 4, the dorsal interossei muscles, in order from the
radial side inwards ; their expanded insertion in connection with the extensor tendons, is
shown upon the first phalanges.

Fig. 183.—Tur Rigut Hanp FROM BEFORE, SHOWING THE PALMAR InTHROSSEI

Musciis. ?
1, 2, 3, refer to the first, second, and third palmar interosseous muscles.

to a common tendon in the middle. Each terminates in a tendon,
which is inserted partly into the base of the first phalanx, and partly into
the tendon of the common extensor muscle on the dorsum of the same
part of the finger. ‘Two dorsal interossei are inserted into the middle
finger and draw it to either side ; of the remaining muscles one passes
to the radial side of the index-finger, and the other to the ulnar side
of the ring-finger ; they withdraw those fingers from the middle line of
the hand.

The jirst dorsal interosseous muscle or abductor indicis is larger than
the others ; its outer and larger head of origin arises from the proximal
half of the ulnar border of the first metacarpal bone, the inner is
attached to the whole length of the second metacarpal bone, and be-
tween these heads there is left superiorly an interval wider than in the
other dorsal interosseous muscles,

Relations.—Between the heads of the abductor indicis the radial artery passes
forwards to the palm of the hand ; between those of the other dorsal interossei
small perforating arterial branches are transmitted.

The three palmar interossei muscles are adductors, drawing the
index, ring, and little fingers towards the middle line of the hand. They
are visible only from the palmar aspect of the hand, each one arising
from the concave part of the body of the metacarpal bone of the finger
on which it acts: they terminate, like the dorsal muscles, in emall

224 MUSCLES OF THE UPPER LIMB.

tendons inserted partly into the base of the first phalanx at the side, and
partly into the extensor tendon. The first palmar interosseous muscle
belongs to the ulnar side of the index-finger: the others are placed on
the radial sides of the ring and little fingers.

Varieties in the short muscles of the hand.—The palmaris brevis varies
greatly in the strength of its muscular fibres, and somewhat also in their length
and direction. It is sometimes entirely absent (in the proportion of one in forty-
five out of six hundred dissections by Macalister). It is also sometimes found
running into the flexor minimi digiti.

The abductor pollicis (brevis) muscle is frequently found divided into an outer
and an inner part,—a condition described by Soemmerring as normal ; and
accessory slips have been observed connected with it,—in some instances pro-
ceeding from the styloid process (Cruveilhier and Turner), and in others from
the opponens pollicis (Macalister).

The flexor brevis pollicis is a variable muscle, especially in its deeper belly, a
part of which shows a tendency to run more or less in connection with the
adductor pollicis ; and in the same manner the latter muscle is subject to varia-
tion in its breadth of origin and extent in inverse proportion to those of the
flexor brevis (Dursy in Henle and Pfeifer’s Zeitsch. 1853).

The abductor minimi digiti is found in some cases partially divided into two
or even into three slips, and in others to be united with the flexor brevis.

The opponentes muscles are subject to varieties chiefly affecting their extent,
and the degree of their union with or separation from the neighbouring muscles.

The interossei muscles present some variations but not of any great magnitude.
They are occasionally double in one or more of the spaces, and sometimes,
though rarely, a palmar interosseous has been observed in the first space (Heale
and Wood). The arrangement which usually exists in the foot, and which is
peculiar to man, has also been observed to occur in the hand.

Nerves of the muscles of the hand.—The median nerve supplies branches
to the abductor pollicis, the flexor brevis and opponens immediately below the
annular ligament, and to the two first Iumbricales muscles from the first and
second digital collateral nerves respectively. The ulnar nerve, besides giving a
twig to the palmaris brevis, furnishes by its deep palmar division branches to
the two internal Iumbricales, all the interossei, the adductor, and the deep head.
of the flexor brevis pollicis muscles.

ACTIONS OF THE MUSCLES OF THE FOREARM AND HAND.

The muscles of the forearm may be distinguished according to their actions as
pronators and supinators, flexors and extensors of the wrist, and long flexors and
extensors of the fingers; those of the hand are flexors and extensors, adductors,
abductors and opposers of the fingers; the terms adduction and abduction being
here used with reference to the middle of the hand.

Pronation is mainly effected by the pronator teres and pronator quadratus : the
flexor carpi radialis also contributes slightly to this movement. The pronator
teres is fitted to flex the elbow when pronation has been completed, or when it
is prevented by antagonistic muscles.

Supination is effected principally by the supinator brevis, the supinator
longus only partially accomplishing this action, The latter muscle is principally
a flexor of the elbow, acting, however, only after that movement has been
begun by other muscles. By the successive and alternating action, howeve7, of
the pronators and supinators and of the flexors and extensors of the carpus, a
more complete rotation of the hand is produced, so that the ulna as well as the
radius moves round a fixed axis which is nearly in the line of the middle finger,
as may be well seen in the use of a corkscrew or other like movements. When
still more extensive movements of this kind are effected, they are accompanied
by rotation of the whole limb at the shoulder-joint.

Flexion of the wrist is produced by the radial and ulnar flexors of the carpus,
and is aided by the flexors of the fingers when the action of those muscles on

ACTION OF MUSCLES OF FOREARM AND HAND. 225

the fingers is either completed or is opposed by any resistance, as wnen the
over-extended hand is pressed against a surface in pushing, or in the support of
the body.

Extension of the wrist,in a similar manner, is accomplished not only by the
three muscles specially devoted to that function, but also by the extensors of the
fingers.

To ensure the efficient action of the long extensor and flexor muscles of the
fingers it is necessary that there should be simultaneous action of the flexors and
extensors of the wrist respectively ; for the wrist-joint must be fixed backwards
by its extensors in order that the long flexors of the fingers may act, and the
wrist must be fixed forwards by its flexors in order that the long extensors may
act upon the fingers.

The flezor communis digitorum sublimis and the flexor profundus bend respec-
tively the second and the third phalanges of the fingers, while the eatensor com-
munis extends the first phalanx. The four Jwmbricales, on the other hand, and
the seven intcrossci muscles have a double action, in consequence of their insertion
into the lateral expansions of the extensor tendons, and of some of the interossei
directly into the first phalanges. This action consists first, in the flexion of the
fingers at the metacarpo-phalangeal articulations, and second, in extension of the
second and third phalanges. The lumbricales and interossei, therefore, are antago-
nists to both the long flexors and tothe long extensor, This partial and combined
action of the long and short muscles upon the fingers, of which the movements
made in forming the hair-stroke in writing may be taken as an example, has
been well known for a considerable time, especially as regards the lumbricales,
but it has recently been confirmed and elucidated as regards the interossei by the
electro-physiological experiments and pathological observations of Duchenne,
whose interesting work as quotod below,* may be advantageously consulted on
this and other muscular movements.

With respect to the interossci, it is further to be observed that, besides being
flexors of the first and extensors of the second and third phalanges in the manner
previously stated, they severally exercise an abducting or adducting action on
certain fingers, or direct them away from or towards the middle line of the hand,
according to the places of their respective insertions: and thus the four dorsal
interossei are abductors of the index, middle and ring fingers, and the three
palmar interossei are adductors of the index, fourth and fifth fingers respectively.

When the thumb is opposed to the other fingers, the metacarpal bone is drawn
forwards, chiefly by the opponens, the adductor, and the flexor brevis muscles.
The precise action of the abductor is to draw the thumb forwards. The extensor
ossis metacarpi is entirely an abductor, as indicated by the name given to it by
Albinus. The extensor primi internodii likewise is an abductor as well as an
extensor of the first phalanx. The extensor secundi internodii extends both
phalanges and also draws the metacarpal bone backwards. The adductor and the
inner fibres of the flexor brevis adduct the thumb. A combination of the actions
of the different muscles in succession produces circumduction.

The little finger is withdrawn from the others by its abductor, as the ring-
finger is withdrawn from the middle finger by the fourth dorsal interosseous
muscle; and the abductor acting with the long flexors, likewise assists the flcaor
brevis in keeping the first phalanx firmly down in grasping.

While the palmaris longus has the effect of tightening the palmar fascia, the
pulmaris brevis assists in deepening the hollow of the hand by raising the inte-
gument on the inner side, so as to increase the hypothenar prominence.

* Dr. D. B Duchenne, ‘‘ Physiologie des Mouvements, &c.,’’ Paris, 1867.

7

VOL. I. Q

226 MUSCLES AND FASCIZ OF THE LOWER LIMB.

IIL—MUSCLES AND FASCIZ2 OF THE LOWER LIMB.

The muscles which pass between the trunk and the lower limb, viz.,
the psoas, pyriformis, coccygeus, and part of the gluteus maximus, are
so few in number and so intimately connected with others belonging
strictly to the limb, that it is unnecessary to describe them as a dis-
tinct group, as has been done in the case of the more numerous and
considerable muscles which attach the upper limb to the trunk.

FASCIZ OF THE HIP AND THIGH.

The superficial fascia of the lower limb is similar to and continuous
with that of other parts of the body. Over the gluteal region it is very
thick, and assists in forming the prominence of the buttock. On the
front of the thigh it 1s readily divisible into two layers. Of these the
subcutaneous passes freely over Poupart’s ligament, and is continuous
with the subcutaneous layer of the abdominal fascia ; internally it
passes into the tunica dartos of the scrotum and superficial fascia of
the perineum. ‘The deeper layer is separated from the subcutaneous
by the superficial vessels and lymphatics, and is continuous superiorly
and internally with the deeper layer of the superficial fascia of the
abdomen. It is firmly bound down to Poupart’s ligament, to the front
of the fascia lata of the thigh at its upper part, and to the body and
ramus of the pubis. It also covers in and partially fills up the saphenous
opening of the fascia lata, where from its being perforated by numerous
small foramina for the passage of blood-vessels and lymphatics, it
receives the name of cribriform fascia. It is a very thin membrane,
and does not contain much fat. It gradually disappears by becoming
incorporated with the fascia lata about three inches below the groin.

The deep fascia or fascia lata of the thigh is a thin but strong
aponeurotic membrane, consisting of white shining fibrous tissue, quite
devoid of fat, and forming a continuous sheath round the limb. It is
attached superiorly to the posterior surface of the sacrum and coccyx,
to the crest of the ilium, to Poupart’s ligament, to the body and ramus
of the pubis, and to the ramus and tuberosity of the ischium. In the
gluteal region it descends on the surface of the gluteus medius muscle,
as far as the upper border of the gluteus maximus, where it divides
into two layers, one of which passes on the superficial, the other on the
deep surface of that muscle. After encasing the muscle, the layers
unite at its lower and external borders. Over the great trochanter,
where the layers unite externally, and where also the fascia is much
thickened, the upper fibres of the muscle are inserted between the
layers. This thickened portion of the fascia may be traced downwards
on the outside of the thigh, from the crest of the ilium to the outer
tuberosity of the tibia, and to the head of the fibula. This zo-tebial
band consists of dense glistening parallel fibres, and about the junction
of the upper and middle thirds of the thigh it receives the insertion of
the tensor vagine femoris muscle. On the rest of the thigh the fascia
lata varies in thickness. It is thinnest in the upper and inner part of
the thigh, where it covers the adductor muscles. Near the knee it is
considerably strengthened by tendinous expansions given off from the
lower parts of the extensor and flexor muscles of the knee-joint.

In front of the thigh, a little below and external to the inner end of

FASCLEZ OF THE HIP AND THIGH. 227

Poupart’s ligament, is placed the saphenous opening, an aperture in the
fascia lata through which the internal saphenous vein passes to join the
femoral vein, and which receives special attention from its being the
place of exit of femoral hernia. The outer part of this opening lies in
front of the femoral artery, and is bounded externally by a crescentic
margin, the faleiform border, which crosses the surface of the infundi-
buliform sheath of the femoral vessels. This margin in the middle of
its extent is continued into looser tissue, but superiorly and inferiorly
it ends in two more distinct incurved extremities, the superior and
inferior cornua. ‘The inferior cornu, the most completely defined part
of the margin, lies in the angle between the internal saphenous and the
femoral veins, below their junction ; while the superior cornu forms a
larger curve, the inner extremity of which, often called femoral ligament,
passing completely to the inner side of the femoral sheath, is attached
to the front of Gimbernat’s ligament.

It is customary to call the parts of the fascia lata which are placed
external and internal to the saphenous opening the diac and pubic
portions. 'The iliac portion is intimately connected above with Pou-
part’s ligament, as well as with the fascia transversalis and deep layer
of the superficial fascia of* the abdomen, and internally forms the falci-
form margin of the saphenous opening ; the pubic portion, attached
superiorly to the pectineal line, passes on its outer side deeply behind
the sheath of the vessels, with which it is connected, and is continued
into the fascize between the muscles.

The fascia lata is perforated in many places by foramina, wnich
allow the passage of the cutaneous nerves and blood-vessels.

The fascia lata has various deep processes. One of these, leaving
the main fascia at the insertion of the tensor vagine femoris muscle,
passes upwards within that muscle as a strong flat band on the surface
of the vastus externus, and is attached superiorly to the ilium above
the origin of the posterior head of the rectus femoris. ‘Two processes,
the external and mternal intermuscular septa, bind the fascia to the
femur in the lower part of the thigh: the external septum, situated
between the vastus externus muscle and the short head of the biceps,
is inserted into the linea aspera from the lower border of the tendon of
the gluteus maximus to the outer condyle of the bone: the internal
septum, which is much thinner, is inserted into the femur between the
vastus internus and the adductor muscles.

Sheath of the Femoral Vessels——The femoral vessels are surrounded
by an investment of fascia, which in its upper part is particularly dis-
tinct, and receives the name of the crural sheath. This sheath, com-
mencing at the deep crural arch, is continuous with the fascia trans-
versalis and fascia iliaca of the cavity of the abdomen. Its outer
border descends in contact with the artery, while its inner border is
inclined outwards from the margin of Gimbernat’s ligament, and comes
in contact with the vein at the distance of less than an inch lower
down: the sheath is therefore funnel-shaped. It is divided into three
compartments, separated by thin septa: the outermost contains the
artery, the middle one the vein, and the innermost forms a space occupied
at its upper end by the crural ring, and in which there is generally a
lymphatic gland and some fat. Through this passage femoral hernia
descends, and on this account it has been named the crural canal. (See

later, the special account of Hernia.) F
Q a

228 MUSCLES OF THE LOWER LIMB.

MUSCLES OF THE HIP.

The muscles of this region are the three glutei, the pyriformis, the
obturator internus with the gemelli, the obturator externus, and the
quadratus femoris.

Fig. 184.—Suprrrictan Muscirs oF tHe Hip
AND THIGH, SEEN FROM BEHIND, A,T, 2
1, gluteus medius, covered by the fascia

lata ; 2, middle of the gluteus maximus ; 2’,

placed on the fascia lata below the place where

the gluteus maximus is inserted into it, and
above the insertion of the muscle into the
femur; 3, vastus externus; 4, biceps flexor
cruris; 4’, tendon of the biceps, receiving on
its outer side the oblique fibres of the short
head; 5, 5’, semitendinosus; 6, semimem-
branosus ; 7, 7’, gracilis; 8, sartorius ; 9, ad-
ductor magnus ; 10, outer, and 11, inner head
of the gastrocnemius ; 12, placed in the pop-
liteal space, points to the origin of the plantaris.

The gluteus maximus is a very
large and coarsely fasciculated muscle,
somewhat quadrilateral in shape, which

arises from the posterior fifth of the
iliac crest, and from the adjacent
rough surface of the ilium ; from the
posterior surface of the last: piece of
the sacrum; from the side of the
coccyx ; from the great sacro-sciatic
ligament ; and between the sacrum and
the ilium, from the aponeurosis of the
muscles of the back. Thence it passes
downwards and outwards ; the fibres
of its lower third are inserted into
an elongated rough impression, ex-
tending from the base of the great
trochanter to the linea aspera; and
hose of the upper two-thirds into a
vhickened portion of the fascia lata of
the thigh over the great trochanter ;
a few of the lowest fibres also ter-
minate in the fascia.

Relations.—The lower border of the mus-
cle lies in the fold of the nates. The deep
surface rests on the gluteus medius and
pyriformis muscles, the tendon of the ob-
turator internus, with the two gemelli,
the quadratus femoris, a small portion of
the adductor magnus, the great trochanter,
the ischial tuberosity, and the origin of the
hamstring muscles ; it covers also the sciatic artery and nerves as they emerge
from the pelvis below the pyriformis, the superficial branch of the gluteal
artery passing out above that muscle, and the pudic artery and nerve lying
behind the spine of the ischium.

Between the tendon of the muscle and the great trochanter of the femur, are

GLUTEAL MUSCLES. 229

placed two or three synovial burse, or a single multilocular bursa of large size,
A bursa is also situated between the muscle and the tendon of the vastus externus,
and another separates it from the tuber ischii.

The great size of the gluteus maximus and the consequent prominence of
the buttock, is a characteristic of man as compared with those animals which
most nearly approach him in general structure.

Varicties—This muscle varies chiefly in the extent of its origin; it may
obtain a high fascial slip from the lumbar aponeurosis, or it may be attached
only to the last two sacral vertebrae. It may also be considerably subdivided.
Thus it has been seen wholly or partly bilaminar (Tiedemann, Macalister) ; or
with a separate muscle, constituting in animals the agitator caude attached to
the coccyx and lowest part of the sacrum (Macalister).

The gluteus medius muscle, covered partly by the gluteus maximus,
partly by the fascia lata, arises from the surface of the dorsum ilii
above the superior curved line, and in front of the gluteus maximus,
from the strong fibres of the fascia lata, covering its outer surface.
The muscular fibres converge as they descend, the anterior fibres
passing obliquely backwards, the posterior fibres obliquely forwards, and
terminate in a fan-shaped tendon, which is inserted ito an oblique
line directed downwards and forwards on the outer surface of the
great trochanter. The tendon is separated by a smal! bursa from the
upper part of the trochanter.

Relations.—Between this muscle and the gluteus minimus are the gluteal nerve
and deep branches of the gluteal artery. At its anterior and inferior border its
fibres are parallel to and united with those of the gluteus minimus. This border
also is in contact with the tensor vaginz femoris, The posterior border is in
contact with the pyriformis, being separated by the gluteal vessels and nerves.

Varictics—The gluteus medius has been found bilaminar by Henle. It may be
united posteriorly by a tendinous slip to the tendon of the pyriformis, or the two
tendons may be separated by a bursa (the bursa ef Loder). This last condition
occurs once in eyery fifteen subjects (Macalister).

Fig. 185.—Drre Muscies or tun Hip on Fig. 185.

tHE Lert SIDE, FROM BEHIND. 1}

The gluteus maximus, and the muscles of
the thigh have been removed. 1, gluteus
medius; 2, pyriformis ; 3, gemellus su-
perior ; 4, gemellus inferior ; 5, obturator
internus, seen partially within the pelvis,
and, after issuing by the lesser sciatic notch,
between the gemelli muscles; 6, quadratus
femoris ; 7, tendon of the obturator ex-
ternus between the gemellus inferior and
quadratus.

The gluteus minimus, covered
by the preceding muscle, arises from
the whole space on the dorsum ilii
between the superior and inferior
curved lines. ‘The fibres, converg-
ing as they descend, terminate in
an aponeurotic tendon on the outer
surface of the muscle, which be-
coming narrowed is inserted into
an impression on the anterior
border of the great trochanter. ‘The tendon is bound down to the
prominence of the trochanter by a strong fibrous band whicn joins

230 MUSCLES OF THE LOWER LIMB.

it from the upper margin of the capsule of the hip-joint. A synovial
bursa is interposed between the tendon and the trochanter.

Relations.—The anterior border of the muscle is in contact with that of the
gluteus medius ; its deep surface with the capsule of the hip joint, the dorsum
ilii, and the posterior head of the rectus femoris: its outer surface is covered
by the gluteus medius, gluteal vessels and nerves; and its posterior border is
covered by the pyriformis muscle.

Varieties—This muscle may be divided into an anterior and a posterior part,
or it may send detached slips to the hip joint, to the pyriformis, to the gemellus
superior, or to the outer part of the origin of the vastus externus (Macalister).

The pyriformis muscle arises within the pelvis by three fleshy
digitations from the second, third, and fourth divisions of the sacrum,
between the anterior sacral foramina, slightly from the deep surface of
the iliac bone, near the sacro-sciatic notch, and from the sacro-sciatic
ligament. The muscle passes out of the pelvis by the great sacro-
sciatic notch, and is inserted by a rounded tendon into the upper
border of the great trochanter, being bound down for some distance
from the point of its final insertion to the subjacent tendon of the
obturator internus and gemelli muscles.

felations.—The pyriformis muscle, after escaping from the pelvis, is in contact
by its upper border with the gluteus medius and minimus, the gluteal vessels and
nerve intervening ; and by its lower border with the superior gemellus muscle,
the sciatic vessels and nerves, which emerge beneath it, lymg between ; its outer
surface is covered by the gluteus maximus, and its deep surface is in contact with
the capsule of the hip joint.

Varicties.—This muscle is frequently found to be pierced by the great sciatic
nerve or by its external popliteal branch, and is thus divided more or less com-
pletely into two parts. It may be united with the gluteus medius, superior
gemellus, or obturator internus. It may have only one or two sacral attach-
ments, or again its tendon may be inserted into the hip joint. Its entire absence
has also been noted.

The obturator internus muscle, in great part lodged within the
pelvis, arises from the deep surface of the obturator membrane ; from
the fibrous arch which completes the canal for the obturator vessels and
nerves; from the bone surrounding the obturator foramen, extending
downwards to the outlet, backwards as far as the sciatic notch, and
upwards to the brim of the pelvis; a few fibres also arise from the
obturator fascia, which is in contact with the deep surface of the
muscle. Its fibres converging as they proceed backwards from this
origin, the muscle emerges from the pelvis by the small sacro-sciatic
foramen, gliding over the trochlear surface of the ischium, and is directed
outwards, to be inserted, in connection with the gemelli, into the upper
part of the digital fossa of the great trochanter. The tendon, occupying
the surface of the muscle which is towards the bone, is folded together
into four or five plaits which lie side by side as they turn over the trochlear
groove : their motion in that groove is facilitated by a synovial bursa,
which is inflected over them, and by a thin coating of cartilage on the
trochlear surface of the bone. Another bursa, of much smaller size,
elongated and narrow, is placed between the tendon and the fibrous
capsule of the hip-joint. These burs are sometimes continuous with
one another

Relations.—The deep surface of the pelvic portion is in contact with the deep
pelvic fascia and near its lower border with the pudic vessels and nerve. The
outer surface is in contact with the bones and obturator membrane. At its upper

SHORT ROTATORS OF THE THIGH. 231

torder the obturator vessels and nerve pass through the obturator foramen. The
extra-pelvic portion lies between the gemelli and in contact with the ischium
and capsule of the hip joint. It is covered by the great sacro-sciatic ligament,
the sciatic vessels and nerves, and by the gluteus maximus,

The gemelli (gemini) are two small narrow muscles, consisting
chiefly of fleshy fibres extended horizontally at each side of the tendon
of the obturator internus ; and they are named from their position
above and below the tendon. The gemellus superior, which is usually
the smaller muscle, arises from the ischial spine ; the gemellus inferior
takes origin from the upper and back part of the tuberosity of the
ischium. Passing outwards, they join the tendon of the internal
obturator muscle, covering and concealing it more or less, and along
with it are inserted into the digital fossa of the trochanter. Some of
their fibres, especially from the superior gemellus, run obliquely into
the tendon of the obturator.

Relations —The superior gemellus is placed immediately below the pyriformis ;
the inferior gemellus is above the quadratus femoris, and at its insertion is close
to the tendon of the obturator externus muscle. These muscles may be regarded
as portions of the obturator internus arising externally to the pelvis.

Varieties—The gemellus superior is often very small, and in some cases is
altogether absent. The gemellus inferior has also been found absent, but more
rarely than the upper muscle.

The quadratus femoris muscle, of an oblong shape, arises from the
external border of the tuber ischii, and, proceeding horizontally outwards,
is inserted into the greater part of the /nea quadrati on the posterior
surface of the great trochanter of the femur.

Relations.—Superiorly this muscle is close to the inferior gemellus. Its inferior
border is in contact, at its origin, with the descending fibres of the adductor
magnus, and at its insertion with the superior or horizontal fibres. It conceals
the outer part of the obturator externus, and also the lesser trochanter, which is
separated from it by a small bursa.

Varieties —It may be entirely absent and replaced by an enlarged gemellus
inferior.

The obturator externus muscle arises from the outer surface of
the anterior two-thirds of the obturator membrane, from the outer
surface of the body of the pubis, and from the rami of the pubis and
ischium ; its fibres extend horizontally outwards and backwards, con-
verging to a tendon which is directed along the groove between the
acetabulum and the tuberosity of the ischium, im contact at the same
time with the under and hinder surfaces of the neck of the femur to be
inserted into the trochanteric fossa below the obturator internus and
gemelli.

Eelations.—The deep surface of the muscle is in contact with the obturator
membrane, while the obturator vessels and nerves pass over its upper border. Its
anterior surface is covered by the upper borders of the pectineus, adductor brevis,
and adductor magnus; in the groove beneath the acetabulum it is in contact
with the lower and posterior parts of the capsule of the femur, and close to its
insertion it is concealed by the quadratus femoris.

Nerves.—The gluteus maximus is mainly supplied by the small sciatic nerve,
but also receives at its upper part a separate branch from the sacral plexus. The
gluteus medius and minimus are supplied by the gluteal nerve. The pyriformis,
gemelli, obturator internus, and quadratus femoris receive special branches from
the sacral plexus. The obturator externus is supplied by the obturator nerve..

MUSCLES OF THE LOWER LIMB.

to
co

Actions.—The gluteus maximus muscle is the chief extensor of the hip-joint
By means of it the bent thigh is brought into a line with the body. It is not in
action in the ordinary movements of walking or in standing on level ground, but
it is so in ascending an incline or a stair, and in the exercises of leaping or
dancing, and in rising from the sitting posture. Its most powerful action, and
that in connection with which it is so largely developed in the human subject, is
to extend the trunk upon the high when bent forward. The muscle acts also as
an adductor and external rotator of the limb. But although the full contraction
of the glutei maximi is required to bring the body into the erect posture, it is
not necessary for its maintenance when complete, that being effected chiefly by
the tension of certain ligaments and fasciz passing over the joints, while the body
is so poised that the centre of gravity of the trunk is placed slightly behind the
vertical plane passing through the middle of the hip-joints. The gluteus medius
and minimus are powerful abductors of the thigh, and along with the tensor
vagine femoris, come principally into action in supporting the body on one
limb, and in the rotation of the pelvis on the two limbs alternately which takes
place in walking. Their anterior fibres draw forwards the great trochanter, and
rotate the limb inwards, while the posterior part produces outward rotation.

The pyriformis, obturator internus, gemelli and quadratus femoris muscles sup-
port the hip-joint posteriorly, and rotate the limb outwards. These muscles may
also act as extensors when the thigh is strongly flexed.

The obturator externus, besides being an external rotator, is also a flexor and
adductor of the thigh, as is the case in the uppermost of the two limbs when we
cross the knees in sitting. It supports the hip-joint posteriorly and inferiorly.

POSTERIOR FEMORAL OR HAMSTRING MUSCLES.

At the back of the thigh are three long flexor muscles of the knee-
joint ; viz., the biceps, semitendinosus, and semimembranosus.

The biceps flexor cruris muscle consists of two parts, arising one
from the hip-bone, the other from the femur, which unite inferiorly to
terminate on the fibula. The long head arises by a tendon common
to it and the semitendinosus from the most prominent part of the
ischial tuberosity; the short head arises from the outer lip of the linea
aspera in its whole extent, from the upper part of the line leading
thence to the outer condyle, and from a part of the adjacent external
intermuscular septum. The muscular fibres from both heads end in
a common tendon, which is inserted into the head of the fibula by two
portions, one on each side of the external lateral ligament of the knee-
joint. Some of the fibres of the tendon, passing forwards and down-
wards, are inserted into the front of the tibia, and others passing
backwards strengthen the fascia of the leg.

Relations—The origin of the biceps is covered by the gluteus maximus, the
rest of the muscle is subcutaneous. It rests upon the head of the semimembra-
nosus, the great sciatic nerve, and the adductor magnus; its inner border is in
contact with the semi-tendinosus and at its lower end it forms the upper and
outer boundary of the popliteal space.

Varietics.—The short head may be absent, or there may be an additional long
head arising from the tuber ischii, or from the linea aspera, or from the inner
condylar ridge of the femur, or from various other parts. A slip has been found
passing from the long head to the tendo Achillis (Otto).

The semitendinosus muscle, closely united at its origin with the
biceps, arises from the tuberosity of the ischium, and from the tendon
common to it with the biceps, for about three. inches ; it descends on
the back of the thigh, and terminates below the middle in a long,
rounded, and slender tendon, which passes along the inner side of the

SEMIMEMBRANOSUS.,

233

popliteal space, resting on the semimembranosus, and curves forwards
to be inserted in an expanded form into the upper part of the tibia at

its inner side. There the tendon is on
the same plane with, but below that of
the gracilis, both being under cover of
the sartorius. A thin oblique tendinous
intersection traverses the muscle about
the middle.

Fig. 186.—Drxp Muscies or Tue Ricut Hip
AND THIGH, FROM BEHIND. (A.T.) 1

a, anterior, a’, posterior superior spine of
the ilium; 0’, posterior inferior spine; ¢, c,
great and small trochanter ; d, symphysis pubis ;
é, tuberosity of the ischium ; f, popliteal surface
of the femur ; g, head of the fibula ; 1, gluteus
minimus ; 2, obturator internus: the gemelli
muscles have been removed ; 3, obturator ex-
ternus ; 4, small part of the back of the
pectineus and adductor brevis ; 5, origin of the
adductor magnus from the lower part of the
ischial tuberosity ; 5’, 5’, line of insertion of
this muscle on the linea aspera, in which are
seen three arched tendinous intervals for the
passage of the perforating vessels ; 5”, tendon
of insertion into the inner tuberosity of the
femur; between the lower 5’ and 5", the inter-
val through which the femoral vessels pass into
the popliteal space ; the upper 5’ is placed upon
the cut end of the quadratus femoris ; 6, vastus
externus ; 7, vastus internus ; 8, femoral head of
the biceps femoris : the lower part is represented
as passing too far inwards; 8’, its ischial head,
cut short; 9, plantaris muscle: at its upper
end the outer head of the gastrocnemius; the
figure 5”, is upon the cut inner head; 10, pop-
liteus, cut short below ; 11, tendon of the semi-
membranosus; 12, upper part of the soleus.

The semimembranosus muscle
arises from the tuberosity of the
ischium, above and to the outside of
the origin of the biceps and semi-
tendinosus, by a strong flattened ten-
don, two or three inches long, which,
as it descends in front of the common
tendon of those two muscles, passes
to their inner side. The muscle pre-
sents inferiorly a thick fleshy belly,
ending in a short flattened tendon,
which is inserted in three parts: the
principal part turns forwards and is
inserted into a well-marked groove on

the inner tuberosity of the tibia, beneath the internal lateral ligament
of the knee-joint, some of its fibres joining that ligament ; a second
part, passing downwards and outwards, expands in the aponeurosis
over the popliteus muscle ; and the remaining fibres are directed upwards
and outwards, and blend with the posterior ligament of the knee-joint,

234 MUSCLES OF THE LOWER LIMB.

of which they may be said to form a considerable portion. The muscle
consists of numerous short fibres extending obliquely between two
aponeurotic expansions, which are continued upwards and downwards
on the opposite sides of the muscle for three fourths of its length from
the superior and inferior tendons.

Relations —The inferior tendon of the semimembranosus muscle is separated
from the tendon of the inner head of the gastrocnemius by a large bursa, The
muscle rests on the adductor magnus.

The hamstring muscles descend in contact with one another, being bound down
by the fascia lata ; but inferiorly they diverge, the biceps passing to the outside,
and the semimembranosus and semitendinosus to the inner side of the knee, ,
forming the superior borders of a diamond-shaped hollow at the back of the knee
—the popliteal space. The great sciatic nerve is concealed by them while they
are in contact, and its principal division, the internal popliteal, lies in contact
with the semimembranosus muscle in the popliteal space, while the smaller or
external popliteal division runs along the edge of the biceps muscle.

Varieties. —The semimembranosus muscle has been found absent ; again it has
been found double or it may have its origin for the most part from the great
sciatic hgament.

Nerves.—The hamstring muscles are all supplied with branches from the great
sciatic nerve.

Actions.—The hamstring muscles extend the hip and flex the knee. It is to be
observed, however, that in ordinary circumstances these movements take place
together, and that therefore it is by the occurrence of simultaneous action of
other muscles that it is determined whether flexion of the one or extension of
the other will occur.

The short head of the biceps is the only flexor of the knee which passes over
that joint alone. The action of the whole muscle produces external rotation of
the leg.

ANTERIOR MUSCLES OF THE THIGH.

The 11L10-PsoAs muscle, the great flexor of the hip-joint, is divisible
into two parts, a broad outer part, the iliacus, and an elongated inner
part, the psoas magnus, which are inserted together into the small
trochanter.

The iliacus muscle arises from the iliac fossa of the innominate
bone, and from the anterior border of the same, likewise from the base
of the sacrum, the ilio-lumbar ligament, and the capsule of the hip-
joint. Its fibres converging, as they pass downwards and inwards, are
inserted for the most part into the tendon of the psoas muscle ; while
some are prolonged to a special triangular impression on the upper part
of the femur, in front of and below the small trochanter.

Relations —Above Poupart’s ligament this muscle is covered by the iliac fascia,
the external iliac artery, the ilio-inguinal and external cutaneous nerves. Outside
the pelvis it lies on the capsule of the hip-joint ; in front of it lie the anterior
crural nerves; at its outer border are the origins of the sartorius and rectus
femoris muscles, and at its inner is the psoas.

Varicty—The chief variety consists in the presence of the iiacus minor or
ilio-capsularis, a small detached portion of the iliacus major. It arises from the
anterior inferior spine of the ilium, and is inserted into the anterior intertro-
chanteric line of the femur. It is closely united to the front of the capsule of
the hip-joint.

The psoas magnus muscle arises by five fleshy slips from the anterior
surface and lower margin of the transverse processes of the lumbar
vertebrie near their bases ; also from the bodies of the last dorsal and

TENSOR VAGINA, FEMORIS MUSCLE, 235

all the lumbar vertebrae in the following manner :—EHach slip takes
origin from an intervertebral disc, and from the contiguous margins of
the bodies of two vertebre, the highest being attached to the neigh-
bouring margins of the last dorsal and first lumbar vertebre, and the
lowest to the fourth and fifth lumbar vertebree with the intervertebral
substance between them. These attachments are connected by thin
tendinous arches extending over the middle of each vertebra, covering
the lumbar vessels and communicating branches of the sympathetic
nerve, and giving origin to other muscular fibres. The various bundles
of fibres speedily unite to form a thick elongated muscle, which runs
along the brim of the pelvis, and emerging from the abdomen beneath
Poupart’s ligament is inserted into the small trochanter of the femur
by means of a tendon, which is placed at first within the substance of
the muscle, and afterwards at its outer side, receiving in this manner
the fibres of the iliacus as well as those of the psoas.

Relations,—The psoas muscle, at its superior extremity, passes behind the dia-
phragm, below the arch of the ligamentum arcuatum internum, Posteriorly it is
in contact with the quadratus lumborum muscle and the os innominatum.
Resting on its inner border along the margin of the pelvis, is the external iliac
artery, and deeply in the substance of the muscle is the lumbar plexus of
nerves. The ilio-inguinal and external cutaneous nerves cross the iliacus muscle,
and the anterior crural nerve descends on the tendon of the psoas. The iliac
fascia extends over the surface of the whole ilio-psoas muscle in the abdomen.
After emerging from the abdomen beneath Poupart’s ligament, and turning
over the brim of the pelvis, the tendon of the psoas rests on the capsule of the hip-
joint, on which it glides by means of a large synovial bursa, which occasionally com-
municates with the interior of the joint; its outer margin is in contact with the
rectus muscle, and its inner margin is separated from the pectineus by the in-
ternal circumflex artery.

Variety.—The psoas parvus, an occasional muscle, placed on the surface of the
psoas magnus, arises from the bodies of the last dorsal and first lumbar vertebree,
and from the fibro-cartilage between them, and soon ends in a flat tendon, which
passes along the front and the inner side of the psoas magnus, to be inserted into
the ilio-pectineal line and eminence. This muscle, although it is well developed
and constant in animals, is most frequently absent in the human subject. It
was found in only one of twenty bodies examined by Theile with special refer-
ence to its existence. When present, it is liable to many changes in the place of
origin ; thus, it may be connected only with the first lumbar vertebra, or with
the second and the intervertebral substance above it, and it has been observed to
commence by two parts or heads separated by an interval,

The tensor vagine femoris, or ilio-aponeurotic muscle of the
thigh, arises by muscular and tendinous fibres from the external surface
of the iliac crest close to its fore-part, and from part of the notch
between the two anterior iliac spines, external to the attachment of the
sartorius ; and passing downwards and a little outwards it is inserted
between tio laminz of the fascia lata, from three to four inches below the
great trochanter of the femur. The outer of these lamine is continued
upwards on the muscle in its whole extent, being part of the general
investment of the limb, the deeper is connected above with the origin
of the rectus muscle, and with the fibres attaching the gluteus minimus
to the hip-joint. The part of the fascia, made tense by the action of
the muscle, forms a strong tendinous band, which descends to the outer
surface of the anterior tuberosity of the tibia.

Relations.—This muscle lies upon the anterior border of the gluteus minimus,
the upper parts of the rectus femoris and vastus externus muscles, and the

236 MUSCLES OF THE LOWER LIMB.

ascending branches of the external circumflex artery. At its origin it lies
between the sartorius and anterior border of the gluteus medius muscles,

SS yi

SS

Fig. 187.—Dxxp Dissection or THE MuscLEs OF THE ABDOMEN AND Prtyis. (A.T.) 3

a, twelfth dorsal vertebra ; }, fifth lumbar vertebra; ¢, transverse process of the first
lumbar vertebra ; 1, quadratus lumboram muscle; on the left side, its fibres of origin
from the transverse processes of the lumbar vertebre are shown by the removal of the
psoas muscles ; 2, placed upon one of the intertransversales muscles of the left side; 3,
the upper part of the psoas parvus, drawn somewhat to the outer side; 3’, the inser-
tion of its tendon into the brim of the pelvis; 4, the upper part of the psoas magnus ;
4", one of the origins of the muscle; 4, the insertion of the muscle into the lesser
trochanter of the femur ; 5, iliacus shown fully on the left side by the removal of the
psoas muscles ; 5’, insertion of the iliacus muscle into a line below the trochanter
minor ; 6, pyriformis muscle of the left side rising within the pelvis from the sacrum ;
6, insertion of its tendon into the summit of the great trochanter ; 7, the obturator
externus seen from before on the left side; ++, the right and left crura of the
diaphragm on the front of the upper lumbar vertebra.

The sartorius muscle is very long, narrow, and ribbon-shaped, and
presents the longest fibres of all the muscles of the body : it arises by a
short tendon from the anterior superior spinous process of the ilium,
and from a small part of the anterior margin of that bone immediately
below, and, passing downwards and inwards across the front of the
thigh, is inserted by an expanded aponeurosis into the inner side of

the tibia, near to the tubercle, and for about an inch below it.

QUADRICEPS EXTENSOR CRURIS MUSCLE. 237

Relations.—In this long course the muscle is directed over the anterior part
of the thigh, obliquely inwards in the upper third, and vertically at the inner
aspect of the limb as far as the knee;
below this it turns obliquely forwards to
its place of attachment. The tendon of
insertion, broad and expanded, covers the
tendons of the gracilis and semitendi-
nosus (a synovial bursa being interposed),
and gives off one expansion which
strengthens the capsule of the knee-
joint by becoming incorporated with it,
and another which blends with the fascia
of the leg.

Fig. 188.—Suprrrician Musches OF THR
Front or tHe Tuigu. (A. 7.) 2

a, anterior part of the crest of the ilium ;
6, symphysis pubis; c¢, patella; d, the an-
terior tuberosity of the tibia; 1, the inser-
tion of the external oblique muscle into the
iliac crest ; 2, its aponeurosis at the linea
semilunaris ; 3, the external abdominal ring ;
4, the gluteus medius; 5, tensor vagine
femoris at the place of its insertion into
a portion of the fascia lata, which has
been removed between 5 and 5’, which latter
part is seen descending to be attached to the
tibia and fibula; 6, the sartorius ; 6’, the
insertion of the sartorius ; 7, psoas and iliacus
conjoined ; 8, pectineus; 9, adductor longus ;
10, gracilis ; 11, part of the adductor magnus
12, vastus externus ; 13, rectus femoris ; 14,
vastus internus ; 14’, its continuation on the
outer side below ; 15, the biceps flexor cruris.

The sartorius is covered only by the
fascia lata and the integument. It passes
over the iliacus and rectus femoris mus-
cles, the anterior crural nerve and fe-
moral vessels, the pectineus, the adductor
longus, adductor magnus, vastus internus
and semitendinosus muscles. The inner
border of this muscle and the most pro-
jecting part of the adductor longus form
the sides, and Poupart’s ligament forms
the base, of a triangular space in the .
upper third of the thigh, through the
middle of which the femoral artery passes.
This usually receives the name of Scarpa’s
triangle.

Varieties—The sartorius has frequently
been found divided into two parts similarly
attached ; or the lower muscle is inserted
into the femur or into the tendon of the
normal one. The tendon of insertion has
been found to end in the fascia lata or in the capsule of the knee-joint. Total
absence of the muscle has also been noted,

_ The quadriceps extensor cruris, the extensor muscle of the knee,
is divisible into four parts, one of which, the rectus femoris, descends
from the hip-bone and remains distinct, while the other three,

238 MUSCLES OF THE LOWER LIMB.

distinguished one from the other only by the arrangement of their
fibres, cover the whole of the anterior and lateral surfaces of the thigh-

bone, from which they arise.

Fig. 189.

Fig. 189.—Dner Musches of THE FRont oF
THE TuicH. (A. 7.) =

a, anterior superior, and 6, anterior inferior
spinous process of the ilium ; ¢, outer and
upper part of the great trochanter ; d, sym-
physis pubis ; e, patella ; 7, inner side of the
knee-joint and internal lateral ligament ; g,
head of the fibula ; 1, the gluteus medius ; 2,
the gluteus minimus ; 38, tendon of the rectus,
dividing above into its two portions ; 4, pomts
to the cut tendon of insertion of the ilio-
psoas muscle ; 5, part of the obturator ex-
ternus and quadratus femoris ; 6, pectineus ;
7, part of the adductor brevis; 8, adductor
magnus; 9, vastus internus ; 9’, its continu-
ation down on the outer side 310, crureus ;
11, vastus externus ; 12, tendon of the rectus;
13, lower part of the slip of the fascia lata by
which the tensor vaginze femoris is inserted
into the tibia and fibula.

a. The rectus femoris muscle ex-
tended in a straight line from the
pelvis to the patella, arises by two
tendons, one of which is attached
to the anterior inferior spinous pro-

_cess of the ilium, and the other united ”

to the first within an inch of that
point, takes origin from the groove
on the dorsum ilii above the brim of
the acetabulum. From the prolonga-
tion of the tendon so formed the mus-
cular fibres arise pennately, and, turn-
ing outwards and backwards as they
descend, are inserted in a similar
manner into the tendon below, the
superior tendon being prolonged on
the anterior, the inferior tendon on
the posterior surface of the muscle.
The inferior tendon forms a broad
band inserted into the upper surface
of the patella.

Relations—Superiorly this muscle is
covered by the tensor vaginee femoris,
iliacus, and sartorius muscles ; further down
it is covered only by fascia. The acetabu-
lar tendon lies beneath the gluteus mini-
mus. The muscle rests upon the capsular

ligament of the hip-joint, the insertion of the ilio-psoas, the crureus, and parts
of the vasti muscles. Behind it also pass the external circumflex artery and

a part of the anterior crural nerve.

b. The vastus externus arises by an extensive aponeurosis attached

VASTUS INTERNUS MUSCLES. 239

to the base of the great trochanter in front, and to a ridge on its outer
side; to the line extending from the great trochanter to the linea
aspera and to the outer border of the linea aspera itself in its upper half ;
the aponeurosis being prolonged on the outer surface of the muscle, also
gives origin to numerous muscular fibres. The muscle forms a somewhat
rhomboidal mass of considerable thickness, and descends obliquely in-
wards and forwards on the outer surface of the vastus internus to be
inserted by a broad flat tendon into the tendon of the rectus muscle
and the patella.

Relations —-This muscle forms the large mass on the outer and upper part of
the thigh. Its deep surface rests on the vastus internus: its outer surface is
covered by the fascia lata and by the aponeurotic insertions of the gluteus
maximus and tensor vagine femoris. Anteriorly it is in contact with the rectus
femoris and external circumflex arteries.

ce and d. The muscles usually described as vastus internus and
erureus are inseparably united and form the inner or deep head of the
common extensor. The fibres of this head may, however, be easily
separated into a superficial and a deep set. The superficial fibres form
a continuous lamina or mantle (Henle) arching over the front and both
sides of the shaft of the femur, and completely enclosing the deeper
fibres which are only seen on cutting through the mantle. These
fibres of the mantle descend in different directions, the middle or
anterior fibres, while arching forwards being nearly parallel to the
femur, and the lateral fibres being more oblique ; this obliquity increases
towards the lower part of the muscle, where the fibres are nearly
horizontal. The anterior fibres arise from the middle of the
anterior intertrochanteric line; the inner lateral fibres arise from
the line running from the anterior intertrochanteric line in front
of the small trochanter to join the inner line leading to the linea
aspera, from the lower half of that inner line, from the inner lip
of the linea aspera, and from the internal intermuscular septum.
The line of origin of the outer lateral fibres runs from the ante-
rior intertrochanteric line obliquely across the front of, and down
the outer surface of the shaft of the femur, immediately in front
of, and closely connected with the origin of the vastus externus.
The lower lateral fibres on the outside of the limb reach consider-
ably beyond the lower border of the vastus externus, taking origin from
the outer lip of the linea aspera and from the external intermuscular
septum. From this extensive origin the fibres converge to the under
surface and margins of a flat tendon which runs upwards for the most
part on the surface of the anterior fibres. This tendon becomes in-
corporated inferiorly with the tendons of the rectus femoris and vastus
externus, and so becomes attached to the upper and lateral margins of
the patella. Many of the lowest lateral fibres on both sides are also
attached directly to the sides of the patella and to the fascia lata at the
sides of the knee-joint.

The deep set of fibres, for which the name of crurews may be still
retained, arises from the anterior aspect only of the shaft of the femur
for about its middle two-thirds, the upper part of the origin being
separated by a slight interval from the origin of the superficial fibres,
end the lower part reaching to within three inches of the patellar
surface. These fibres pass obliquely downwards and forwards to be

240 MUSCLES OF THE LOWER LIMB.

inserted into the posterior surface of the tendon belonging to the
superficial fibres. On either side of the origin of this part of the
muscle there is a longitudinal band of the lateral surface of the femur
from which no muscular. fibres arise: this band varies somewhat in
breadth in different subjects, and it is also broader on the inner aspect
of the shaft than on the outer.

Relations.—On its anterior surface this muscular mass is in contact with the
rectus femoris and sartorius muscles and the anterior crural nerve. At its inner:
border run the femoral artery and vein, and the muscle is in contact with the
iliacus, adductor longus, and adductor magnus, being firmly united to the last
two by the aponeurotic fibres which form Hunter's canal. On its outer surface
lies the vastus externus.

The subcrureus is a small band of muscular fibres, which extends
from the lower part of the anterior surface of the femur to the upper
part of the synovial membrane of the knee-joint, on which it ends in
scattered fibres.

Relations —This little muscle is placed beneath the crureus muscle, and in
some cases it is united with that muscular mass. It is not unfrequently double,
or consists of two separate bundles.

Varietics— The parts of the quadriceps muscle are not liable to many anoma-
lies. The rectus has been found with an additional origin from the anterior
superior spine of the ilium; or, again, its acetabular origin may be wanting.
The vasti muscles are sometimes bilaminar, as is seen also normally in many
birds.

Nerves.—The psoas muscle is supplied by small branches from the lumbar
plexus. The iliacus, quadriceps extensor cruris and sartorius are supplied by the
anterior crural nerve, and the tensor vagine femoris by the superior gluteal
nerve.

Actions.—The ilio-psoas muscle, the flexor of the hip-joint, bends the thigh on
the body, or the body on the thigh, according as either of these is the more
fixed. It also produces considerable rotation outwards.

The tensor vagine femoris assists the action of the other muscles by making
tense the fascia lata. It aids the gluteus medius and minimus in rotating the
limb inwards, but its action in this respect is exactly opposed by the upper fibres
of the gluteus maximus, along with which it acts as an abductor of the limb,
and is considered by Meyer (op. cit. p. 222) to be an extensor of the knee.

The sartorius produces the flexion of the hip and knee-joints, accompanied by
abduction. It has been supposed to be the muscle principally concerned in pro-
ducing the posture assumed by the tailor in sitting, and hence its name; but
Duchenne denies that this is its special action.

The quadriceps extensor femoris extends the knee-joint ; but its action is not
requisite for the maintenance of the erect attitude, the knee-joint remaining in
complete extension without muscular aid while the foot is firmly planted on the
ground. This may be tested by the fact that the patella of a person standing with
the knee extended will be found to le quite loosely, but will become at once
fixed when it is attempted to lift the foot.

The rectus femoris flexes the hip and extends the knee: it acts mainly from its
anterior head of origin when the thigh is fully extended, and the posterior head
is alone tense when the thigh is bent.

INTERNAL FEMORAL OR ADDUCTOR MUSCLES.

The gracilis or adductor gracilis muscle, long and slender, arises
by a thin tendon from the inner margin of the pubic bone, along
the lower half of the symphysis and the upper part of the pubic arch.
The lower tendon, which is at first round, is inserted by a flattened and

THE ADDUCTOR MUSCLES 241

expanded portion into the inner side of the tibia, on the same plane
with but higher than the semitendinosus, and under the expanded
tendon of the sartorius.

Relations.—This thin muscle is covered by the fascia lata, except in a small
part inferiorly, where it is overlapped by the sartorius ; the deep surface rests
against the adductor brevis, adductor magnus, semimembranosus, and the in-
ternal lateral ligament of the Imee-joint. A bursa separates it from that
ligament.

The pectineus muscle, flat and somewhat quadrangular, arises from
the pectineal line, and from the surfacz of bone in front of it, between
the iliopectineal eminence and the pubic spine. Inclining outwards and
backwards as it descends, it is inserted by a flat tendon into the femur
behind the small trochanter, and into the upper part of the line which
connects the linea aspera of the femur with that prominence.

Relations.—The pectineus is in contact, by its anterior surface, with the fascia
lata and the femoral vessels ; by the posterior surface, with the obturator vessels
and nerve, and the external obturator and adductor brevis muscles, By the
outer border it touches the psoas magnus; by the inner border, the adductor
longus.

Varictics—The pectineus is frequently divided into two parts, which are
separate superiorly and have their nerves from different sources, viz., the inner
from the obturator and the outer from the anterior crural nerve. This division
occurs naturally in many animals.

The adductor longus, a flat triangular muscle, internal to the pec-
tineus, and lying in the same plane, arises by a short tendon from the
body of the pubes below the crest and near the angle, and is inserted
into the inner margin of the linea aspera between the vastus internus
and the adductor magnus.

Relations.—This muscle is covered by the fascia lata, the sartorius, and the
femoral vessels ; the posterior surface rests superiorly on the adductor brevis, and
inferiorly on the adductor magnus. Externally it is separated by a small interval
from the pectineus, and internally it is in apposition with the gracilis, It forms
the inner boundary of Scarpa’s triangle.

The adductor brevis, thick above and broad below, arises by a
narrow origin, about two inches deep, in contact with that of the gracilis,
from the anterior surface of the body, and the descending ramus
of the pubes ; directed obliquely backwards and outwards, it is inserted
by a flat tendon into the whole of the oblique line leading from the
small trochanter of the femur to the linea aspera, immediately behind
the insertion of the pectineus.

Relations—The adductor brevis is concealed at its origin by the adductor
longus and at its insertion in part by the pectineus; it is crossed by the super-
ficial division of the obturator nerve, and by the profunda femoris artery; it
rests on the adductor magnus and deep division of the obturator nerve, and by
its deep surface is in contact superiorly with the obturator externus, the internal
circumflex artery passing between.

The adductor magnus muscle arises from the lower part of the body
of the pubis external to the origin of the adductor brevis, from the
rami of the pubis and ischium, and from the tuberosity of the ischium
near the pubic arch. The muscular fibres diverge from their origin,
somewhat like the ribs of a fan from their central pivot : those from

the pubis, shorter than the rest, pass transversely outwards, and are
VOL. I. R

242 MUSCLES OF THE LOWER LIMB.

inserted into the tower part of the linea quadrati, and into the line
prolonged from the linea aspera to the great trochanter ; others pass
with increasing degrees of obliquity downwards and outwards, to be
inserted into the whole length
Fig. 190. of the linea aspera, and into the
line prolonged from it to the
inner condyle for about an inch ;
finally, the posterior fibres which
arise from the ischial tuberosity,
descend almost vertically, form-
ing the inner border of the mus-
cle, and terminate in a narrow
tendon, which is inserted into
the tuberosity of the Inner con-
dyle of the femur.

Fig. 190.—Muscrres or THE INNER
Srmpe oF THE TuicH AND INTERIOR
or THE Prenvis, (A.T.) 2

1, iliacus ; 2, psoas magnus; 3, ob-
turator internus, with its fibres con-
verging towards the lesser sciatic fora-
men ; 4, pyriformis, with three heads
of origin, and its fibres converging to-
wards the great sciatic foramen ; 5,
lumbar aponeurosis covering the erector
spine muscle; 6, gluteus maximus ;
7, sartorius, 7’, its tendon inserted
below the tuberosity of the tibia; 8,
adductor longus ; 9, gracilis, 9’, its in-
sertion passing below that of the sar-
torius ; 10, part of the adductor mag-
nus ; 11, semimembranosus ; 12, semi-
tendinosus, 12’, its insertion, and be-
tween 9’ and 12’, the tendon of the
semimembranosus: passing to its mser-
tion in the inner tuberosity of the tibia.

Along the femoral attachment
the insertion is interrupted by
three or more tendinous arches
through which pass the per-
forating arteries, and below the
level of the inferior bifurcation
of the linea aspera, between the
tendinous and fleshy portions
of the insertion of the muscle,
an interval is left for the trans-
mission of the femoral vessels
backwards into the popliteal
space. Extending upwards from
the opening for the femoral ves-
sels, is an aponeurotic membrane which consists of transverse tibres
passing from the surface of the vastus internus to the adductor magnus
and adductor longus muscles. It becomes thinner as it ascends, and
encloses a three-sided passage called Hunter's canal, which contains

FASCLE OF THE LEG, 243

the femoral artery and vein, together with the internal saphenous
nerve.

Relations.—This muscle is in contact in front with the long and short adductors,
the vastus internus, the obturator nerve, and the profunda artery, behind with
the hamstring muscles, gluteus maximus, and great sciatic nerve, internally with
the gracilis muscle, superiorly with the obturator externus and quadratus femoris
muscles, and along the line of attachment to the femur it is pierced by the
femoral and perforating arteries.

Varieties.—The adductor muscles are so closely related that their varieties may
be conveniently considered together. The pectincus has been found double, as
already stated. It has also been seen attached to the capsule of the hip-joint, or
even inserted into it. The adductor longus may be double, or it may extend as
far as the knee with its tendon of insertion inseparable from that of the adductor
magnus. The adductor brevis is frequently found divided into two or three
parts, or it may be incorporated with the adductor magnus. The adductor magnus
varies in the degree of its segmentation. Its condylar part has been found quite
distinct from the rest of the muscle. The upper transverse part is so frequently
divided from the rest by the superior profunda artery, that it is looked upon
by some anatomists as a special muscle, being called the adductor minimus
(Henle, Giinther, Macalister). On the other hand, the muscle has been found
undivided, and its upper part completely united to the quadratus femoris (Mac-
alister).

Nerves.—The adductor muscles as a whole are supplied by the obturator
nerve, but the adductor magnus likewise receives a branch from the great sciatic,
and the outer part of the pectineus sometimes has a branch from the anterior
crural,

Actions.—The gracilis acts as an adductor of the limb. The gracilis, semi-
tendinosus, semimembranosus, and sartorius muscles, together with the popliteus,
all rotate the leg inwards at the knee-joint; the latter muscle acting chiefly in
the flexed state of the knee.

The pectineus is partly a flexor and partly an adductor.

The adductorcs magnus, longus, and brevis, adduct the thigh, and, along with
their opponents the gluteus medius and minimus, and with the gluteus maximus,
balance the body on the femur in walking.

The ilio-psoas and the adductor muscles, together with the pectineus, being all
inserted at the back part of the femur, tend to rotate the thigh outwards at the
same time that they produce their adducting and flexing actions. The advan-
tage of this preponderance of rotators outwards over rotators inwards becomes
apparent by reference to the movements which take place in walking. When a
step is taken, the pelvis is drawn forwards on that side on which the foot has
been advanced, which involves a considerable votation of the pelvis backwards at
the other hip-joint, by the action of the muscles of the opposite limb.

MUSCLES AND FASCIA OF THE LEG AND FOOT.
ANTERIOR REGION,

Fasctz.—The aponeurosis of the leg is particularly dense in the
upper and fore part, and is strengthened by fibres from the tendons of
the biceps externally, and the sartorius, gracilis, and semimembranosus
internally. Behind, over the popliteal space, it consists of strong
transverse fibres, which bind together the muscles of the outer and
inner sides, and is perforated at the lower part of the space by the
external saphenous vein; lower down it becomes much thinner over

the gastrocnemius muscle. The fascia is adherent to the periosteum
R 2

244 MUSCLES OF THE LOWER LIMB.

covering the head, the spine and the posterior margin of the tibia, the
head of the fibula, and the outer and inner malleoli; and it invests
the lee completely except at the inner surface of the tibia. From its
deep surface intermuscular septa are prolonged inwards between the
muscles on the anterior and outer aspects of the leg, and afford attach-
ment along with the upper part of the fascia itself to some of their fibres.

Beneath the gastrocnemius and soleus muscles on the back of the
leg, a deep layer of fascia is stretched from side to side, binding down
the deeper muscles firmly in the hollow between the tibia and fibula.
Where covered by the soleus and gastrocnemius, this fascia is weak,
but it becomes stronger as it escapes from under cover of those muscles
and approaches the malleoli.

Below the ankle the deep fascia of the leg becomes continuous with
that of the foot. In front, and on the sides of that joint, it is
strengthened by broad bands of fibres, which are called annular liga-
ments. These serve as retinacula, confining the tendons in their
natural positions.

The anterior annular ligament includes two structures, one placed
on the lower part of the leg, the other opposite the bend of the ankle.
The upper band, ligamentum transversum cruris (Henle), of considerable
breadth, stretches from the lower end of the fibula to the lower end of
the tibia, and binds down the vertical portion of the extensor tendons
as they turn forwards to the foot: the sheath for the tendon of the
tibialis anticus is distinct from the others. The lower band, ligaments
cruciatum cruris (Henle), presents superficially the appearance of the
letter placed thus upon its side, being single in its outer half, and
usually divided into two branches internally. The outer portion consists
of a strong loop of fibres arising from the fore part of the os calcis, com-
pletely surrounding the peroneus tertius and extensor longus digitorum
muscles, and inserted into the fore part of the os calcis, deep in the
hollow between that bone and the astragalus. Less regular is the
arrangement of the bands which pass from the extremity of the loop to
the inside of the foot: the strongest and most constant band passes
superficial to the extensor pollicis and on the deep surface of the tibialis
anticus muscle, only a few fibres passing superficial to the latter ; while
another band, lower down, after crossing both those tendons, is inserted
into the lower side of the foot in front of the ankle.

The internal annular ligament crosses the space between the
inner ankle and the heel through which the tendons of the flexor
muscles run. Its upper border, continuous with the fascia of the leg
(more especially the intermuscular layer), is very imperfectly defined ;
and its lower border, giving origin to many fibres of the abductor
pollicis, is but little more distinct. Its anterior extremity is attached
to the inner malleolus, and its posterior is inserted into the inner
surface of the caleaneum ; but between these two points it arches over
several osseous grooves so as to form canals for the passage of tendons.
The first canal (next to the malleolus) contains the tendon of the
tibialis posticus, and the second that of the flexor loneus digitorum,
each being provided with a synovial lining. Then follows a wider
space for the passage of the posterior tibial vessels and nerve. Lastly,
a fourth canal upon the astragalus, lined like the first two by a synovial
bursa, transmits the tendon of the flexor longus pollicis.

The external annular ligament extends from the point of the

EXTENSOR PROPRIUS POLLICIS MUSCLE, 245

outer malleolus to the outer surface of the calcaneum, and keeps in
place the tendons of the long and short peronei muscles. The tendons
are close together, and are surrounded by one synovial sac.

The dorsal fascia of the foot is reduced to a thin membrane pro-
longed from the anterior annular ligament over the extensor tendons.
Beneath it, deeper layers of fascize are placed over the short extensor of
the toes and the interossei muscles.

Muscies.—Between the tibia and fibula, and on the front of the leg,
are placed four muscles—the tibialis anticus, extensor proprius pollicis,
extensor longus digitorum, and peronets tertius ; and on the dorsum
of the foot one muscle only arises,—the extensor brevis digitorum.

The tibialis anticus arises from the external tuberosity of the tibia,
and about two-thirds of the outer surface of that bone ; from a small
portion of the adjoining interosseous ligament ; from the strong fascia of
the lee ; and from an aponeurotic septum placed between it and the
extensor longus digitorum. The tendon glides in a synovial sheath
beneath the anterior annular ligament, and is inserted into the inner
and lower part of the internal cuneiform and the contiguous extremity
of the first metatarsal bone, dividing slightly into two slips as it
descends.

Relations.—This muscle is entirely covered by the aponeurosis of the ler. It
rests upon the outer surface of the tibia, and the interosseous ligament. Its
outer surface is in contact above with the extensor longus digitorum. and lower
down with the extensor proprius pollicis; it also conceals the anterior tibial
vessels and nerve. Its tendon passes over the lower end of the tibia, the ankle-
joint, and the inner surface of the tarsus.

Varietics—In cases of talipes the tendon of this muscle has been found split
into two, one half going to the usual place of insertion, the other to the astra-
galus or first metatarsal ; the whole tendon has also been seen inserted into the
plantar fascia. The tibio-fascialis anticus is a small muscle described by Wood,
arising from the lower third of the anterior edge of the tibia over the tibialis
anticus and inserted into the annular ligament and deep tibial fascia. It may
also exist as a tendinous slip from the tibialis anticus.

The extensor proprius pollicis pedis muscle, or extensor hal-
lucis, placed between the tibialis anticus and the extensor longus
digitorum, arises from the middle three-fifths of the anterior narrow
part of the inner surface of the fibula, and from the contiguous portion
of the interosseous ligament. Its tendon passes through a distinct
compartment in the lower portion of the annular ligament in and
along the dorsum of the foot, to be inserted into the base of the ter-
minal phalanx of the great toe. A delicate expansion given off from
the tendon on each side spreads over the joint between the metatarsal
bone and the first phalanx.

Relations.—This muscle is partly concealed by those between which it is placed.
Tt lies external to the anterior tibial artery in the leg, but crosses in front of
that vessel at the bend of the ankle, and is internal to it on the foot.

Varieties—The extensor ossis metatarsi pollicis is a small muscle, sometimes
found as a slip from the extensor proprius, or from the tibialis anticus, or from
the extensor communis digitorum ; or it may be a distinct muscle arising close
to the extensor proprius, and traversing the same compartment of the annular
ligament with that muscle.

The catensor primi internodii pollicis, another occasional muscle is nearly
always an offshoot from the extensor proprius, though it has been found
separate. It was seen by Wood in one half of the subjects examined by him,

246

il

brevis digitorum.

MUSCLES OF THE LOWER LIMB.

The extensor longus digitorum pedis arises from the external
tuberosity of the tibia ; from the head and the anterior narrowed part

hi Hi il
\

part.
Varicties.—This muscle varies considerably in the mode and place of insertion

of its various tendons.

iit

WW

of the inner surface of the fibula in front of
the interosseus membrane, for about three-
fourths of its length ; from a small part of
the interosseus ligament at its upper part ;
also from the aponeurotic septa intervening
between it and the muscles on each side, and
from the fascia of the leg. The tendon
divides into four slips, which descend through
the lower part of the annular ligament, in
the same sheath as the peroneus tertius, and
on the dorsum of the foot pass respectively
to the four outer toes. The three inner
tendons are each joined at the outer side,
on the first phalanx, by a tendon from the
extensor brevis digitorum. All the four ten-
dons are continued into expansions, which
are joined on the first phalanx by tendinous
processes from the lumbricales and interossel
muscles; they divide into three parts, their
middle fibres being inserted into the second
phalanx, while their lateral parts unite to-
gether and are inserted on the third, in a
manner exactly similar to the arrangement
of the extensor tendons of the fingers.

Fig. 191.—Muscrrs or tHe Lea anp Foor From
BEFORE. (A. T.)

1, tendon of the rectus femoris ; 1’, ligamentum pa-
tellxe ; 2, vastus externus ; 3, vastus internus; 4, sar-
torius ; 5, fascia lata cut near the place of its insertion
at the knee ; 6, inner head of the gastrocnemius ; 7,
inner part of the soleus; 8, tibialis anticus; 8’, its
tendon near the insertion ; 9, extensor longus pollicis ;
9’, its tendon ; 10, extensor communis digitorum longus ;
10’, anterior annular ligament; 11, peroneus longus ;
12, peroneus brevis; 13, peroneus tertius; 13’, its
tendon at its insertion ; 14, origin of the extensor com.
munis digitorum brevis, the first head of which is seex
passing to the great toe near the line from 9’.

ole

Relations.—It is in contact internally with the
tibialis anticus and extensor proprius pollicis, and
externally with the peronei muscles. It rests
upon the external tuberosity of the tibia, the an-
terior surface of the fibula, the lower end of the
tibia, the front of the ankle-joint, and the extensor

The anterior tibial nerve passes obliquely beneath its upper

The tendons to the second and fifth toes may be found

doubled, or extra slips are frequently given off from one or more tendons to
their corresponding metatarsal bones or to the short extensor, or to one of

the interossei muscles.

The peroneus tertius muscle arises below the extensor longus

EXTENSOR BREVIS DIGITORUM. 247

digitorum, from the lower fourth of the inner surface of the fibula,
from the lower part of the interosseus membrane, and from the inter-
muscular septum which connects it on
the outer side with the peroneus brevis.
Its tendon is inserted into the upper sur-
face of the base of the fifth metatarsal
bone.

Fig. 192.—Svuprrrictan Muscims anp TENDONS oN
tHE Dorsum oF THE Foor anp Lower Part or
THE Front or THE Lxa (after Bourgery). 3

a, the tibia; 6, the fibula ; c, the scaphoid bone ;
d, internal cuneiform bone; 1, the tibialis anticus
muscle ; 1’, its tendon descending in the groove of
the internal cuneiform bone ; 2, extensor longus pol-
licis ; 2’, its expansion on the dorsum of the great
toe ; 3, extensor communis digitorum dividing into
its four tendons for the toes ; 3’, its expansion, and
3", final insertion (upon the second toe) ; 4, peroneus
tertius ; 4’, its expanded insertion on the base of
the fifth metatarsal bone ; 5, soleus; 6, peroneus
brevis ; 7, extensor brevis digitorum ; 7’, 7”, placed
on the transverse band of aponeurosis, marks the
first and fourth tendons of the extensor brevis muscle
passing to join those of the long extensor; 8, 9,
part of anterior annular ligament, and ligamentum
cruciatum ; between § and ¢, the slings enclosing the
extensor longus pollicis and tibialis anticus ; below
9, the outer part of the ligamentum cruciatum
enclosing the tendons of the extensor communis and
peroneus tertius; 10, 1], dorsal transverse meta-
tarsal band of aponeurosis. ~

felations—Ilt is placed to the outer side of
the long extensor of the toes, with which it is
usually united at its origin, and it passes through
the same compartment of the annular ligament
with that muscle.

Varictics—The peroneus tertius is sometimes as large as the extensor longus
digitorum ; it has been observed to terminate on the fourth metatarsal bone;
and it is sometimes altogether wanting.

The extensor brevis digitorum pedis arises from the outer surface
of the os calcis in front of the groove for the peroneus brevis muscle,
and from the lower band of the anterior annular ligament. It divides into
four tapering slips each of which terminates in a tendon ; the first or
most internal of these, sometimes reckoned as a distinct muscle, is
inserted separately into the dorsal surface of the first phalanx of the
great toe near its tarsal extremity ; and the other three become severally
united to the outer border of the extensor tendons proceeding to the
three next toes.

felations.—It crosses the dorsum of the foot somewhat obliquely, resting on
the tarsus and metatarsus, and lying beneath the tendons of the peroneus tertius
and long extensor of the toes. Its inner tendon also crosses the dorsalis pedis
artery and the anterior tibial nerve,

Varietics—The tendons of this muscle vary considerably both as to number
and position, they may be reduced to two, or one of them may be doubled. The
inner part of the muscle very commonly forms a distinct extensor brevis hallucis
being separate at its origin from the rest of the muscle; this is regarded by
Henle as the normal arrangement.

248 MUSCLES OF THE LOWER LIMB.

Nerves.—All the muscles in frontof the leg, together with the extensor brevis
digitorum, are supplied by the anterior tibial nerve.

EXTERNAL REGION.

The pevoneus longus muscle arises from the head of the fibula, and
from the upper two-thirds of the external surface of that bone ; from the
fascia of the leg ; and from the intermuscular septa on either side. It
ends above the ankle in a tendon which passes downwards behind that
of the peroneus brevis in the hollow behind the external malleolus, and
in the same sheath of the external annular ligament with it ; it then
inclines forwards over the outer margin of the foot, and enters the groove
on the lower surface of the cuboid bone, proceeding inwards and forwards
to be inserted into the lower part of the internal cuneiform and the
tarsal end of the first metatarsal bone : an offset is continued from it
to the base of the second metatarsal bone.

Relations.—At its origin the peroneus longus lies between the extensor com-
munis digitorum in front and the soleus and flexor longus pollicis behind ; in the
lower part of the leg it lies behind the peroneus brevis. Beneath the external
annular ligament the tendons of both peronei are surrounded by the same
synovial sheath. In the sole of the foot the tendon of the peroneus longus lies
in a fibrous sheath formed by the long plantar ligament, and is enclosed by a
tubular sheath of synovial membrane. A small sesamoid cartilage is sometimes
found in that part of the tendon which lies in the groove of the cuboid.

The pexoneus brevis arises from the lower two-thirds of the external
surface of the fibula, internal to the peroneus longus, and from the
intermuscular septa on either side. Its tendon passes behind the
external malleolus, and inclining forwards, is inserted into the projec-
tion at the base of the fifth metatarsal bone.

Relations.—In front it is in contact with the extensor longus digitorum and
the peroneus tertius, and behind with the peroneus longus and flexor longus pollicis.
Behind the malleolus it is enclosed in the same fibrous and synovial sheaths with
the tendon of the peroneus longus, but over the calcaneum it traverses a separate
sheath above that for the peroneus longus, but lined by an offset of the same
synovial membrane.

Varictics—The following are the most common :—The peroneus accessorius
(Henle) arises from the fibula between the peroneus longus brevis and joins the
tendon of the former in the sole of the foot. The peroncus quinti digiti arises
from the lower fourth of the fibula under the peroneus brevis, and 1s inserted
into the aponeurosis on the upper surface of the little toe; or it may arise from
the tendon of the peroneus brevis itself. (Hallet, Wood, Macalister.) Peroneus
quartus (Otto) arises from the back of the fibula, between the peroneus brevis
and the flexor pollicis, and is inserted into a tubercle on the os calcis, behind the
tendons of the peroneal muscles. (Macalister.)

Nerves. —The peroneus longus and brevis are supplied by the musculo-cutaneous
branch of the popliteal nerve.

POSTERIOR REGION,

The muscles at the back of the leg consist of a superficial group
inserted into the extremity of the calcaneum, and a deeper group
covered in by a deep fascia and descending to the sole.

The SUPERFICIAL GROUP consists of three muscles; two of them,
placed one on the surface of the other, are of large size, the gastro-
cnenius and soleus, form the bulk of the calf of the leg, and are
inserted into the heel by a common tendon—the tendo Achillis ; the
third, a small muscle, the plantaris, descends between the other two.

GASTROCNEMIUS MUSCLE, 249

The gastrocnemius muscle arises by two thick tendinous heads from
the condyles of the femur, and ends below in the tendo Achillis, The

Fig. 193.—SuperrictaL Musctes oF THE Lea, szEN Fig. 193
FROM BEHIND (after Bourgery). 4%

1, lower outer part of the vastus muscle; 2,
biceps flexor cruris; 3, semitendinosus; 4, semi-
membranosus ; 5, gracilis ; 6, sartorius ; 7, outer, and
8, inner head of the gastrocnemius ; 9, placed in
the popliteal space, points to the plantaris ; 9’, its
thin tendon inside the tendo Achillis ; 10, the fibres
of the soleus descending to the flat tendon, which
joining with that of the gastrocnemius, forms + +
the tendo Achillis ; 11, peroneus longus ; 12, peroneus
brevis; 13, flexor longus digitorum ; 14, tibialis
posticus ; 15, is placed on the lower part of the
fibula, and points to the lower fibres of the flexor
longus pollicis, the tendon of which is seen descending
over the tibia at 15’.

outer tendon of origin is attached to a
depression on the outer side of the ex-
ternal condyle, above the groove for the
popliteus muscle, and also to the upper and
back part of the same condyle. The inner
tendon is attached in a horizontal line to an
impression above the back part of the in-
ternal condyle, and to a small part of the
ridge running to the ‘linea aspera. The
muscular fibres descending from the two
heads remain separated by a vertical gronve
on the surface, but those next the middle
meet at an angle on a tendinous structure
below. ‘The fibres of the superior tendons
spread out upon the surface of the mus-
cle ; the inferior tendon lies on the deep
surface of the muscular mass, and is con
tinued upwards in a thin aponeurosis witl
parallel fibres, which glide against the
soleus: between the superficial tendon of
each head and the deep common tendon,
the greater number of the muscular fibres
run obliquely downwards and forwards.
The lower edge of each muscular part
presents a convexity downwards ; the inner
descending furthest. A synovial bursa,
usually communicating with the knee-joint,
lies beneath the inner head of origin, and separates it from the tendon
of the semimembranosus muscle. In the outer head a sesamoid fibro-
cartilage is sometimes met with over the outer condyle of the femur,
which is occasionally found ossified.

Relations.—The heads of the gastrocnemius muscle form the inferior boundaries
of the popliteal space, and are placed between the hamstring muscles: the pero-
neal nerve is lodged between the external head and the biceps. The gastrocne-
mius conceals the popliteus, plantaris and soleus muscles, with the popliteal

250 MUSCLES OF THE LOWER LIMB.

vessels and internal popliteal nerve. The short saphencus vein is placed on its
surface, in the interval between its two parts.

Varieties:—The gastrocnemius is, in some cases, joined by a bundle of muscular
fibres, which arises separately from the femur above one of the condyles. This
bundle has been observed passing between the popliteal artery and vein (R. Quain,
op. cit., plate 80, figs. 4 and 5).

Fig. 194. Fig. 194.—Superrictat Muscirs or
THE LEG, SEEN FROM THE INNER
SIDE (after Bourgery). 4
1, vastus internus ; 2, sartorius ;

2', its tendon, spreading on the inner
upper part of the tibia; 3, gracilis ;
4, semitendinosus ; 4’, its insertion ;
and between 2’ and 4’, that of the
gracilis ; 5, semimembranosus ; 6,
inner head of the gastrocnemius ; 7,
soleus ; 8, 8’, placed upon the tendo
Achillis, point to the small tendon of
the plantaris descending on the inner
side; 9, small part of the tendon of
the tibialis posticus ; 10, flexor com-
munis digitorum ; 11, flexor longus
pollicis ; 12, tibialis anticus ; 12’, its
tendon of insertion ; 13, abductor pol-
licis.

The soleus muscle arises
externally from the posterior
surface of the head and upper
third of the shaft of the
fibula ; internally from the
oblique line which gives inser-
tion to the popliteus, and from
the posterior edge of the tibia
about three inches below that
line; and between the tibia
and fibula, from a tendinous
band which arches over the
posterior tibial vessels and
nerve. Inferiorly, the muscular
fibres descend upon the tendo
Achillis considerably further
than those of the gastroc-
nemius. The posterior surface
presents a thin covering of
longitudinal aponeurotic fibres
ccntinued up from the tendon
below, and gliding on the
similar tendinous surface of
the gastrocnemius muscle. On
the deep surface the edges of
two membranous tendons, the other edges of which look towards the
middle line of the muscle, imbedded in its substance, are seen descend-
ing from the tibial and fibular origins : the fibres from the deep
aspects of those tendons are directed obliquely inwards to a tendinous

x 7
ee ets

TENDO ACHILLIS. 251

septum which divides the muscle into lateral halves; while those from
their superficial aspects pass with similar obliquity to the flat tendon
on the surface of the muscle, the fibres

placed at the sides forming the lateral Fig. 195.

borders and part of the deep surface of
the muscles. Thus the soleus is composed
entirely of short oblique fibres of from
one to two inches in length.

Fig. 195.—Drre Postrrion MuscLes oF THE
Lec. (A.T.) 3
@, popliteal surface of the femur ; 0, bare surface
of the upper fourth of the fibula, from which the
soleus muscle has been removed ; ¢, malleolus in-
ternus ; d, malleolus externus ; e, tuberosity of the os
calcis, with a part of the tendo Achillis inserted into
it, and the plantaris on its inner side ; 1, inner head of
the gastrocnemius cut short at its origin ; 2, outer
head; 3, plantaris; 4, tendon of the semimem-
branosus muscle near its insertion, seen spreading in
‘three portions, viz., to the inside of the tibia, towards
the popliteal fascia, and towards the ligamentum
posticum ; 5, tendon of the biceps inserted into the
head of the fibula ; 6, popliteus muscle ; 7, upper
part of the origin of the soleus from the fibula, cut
short ; 7’, line of its tibial origin ; between these
figures is seen the perforation in the upper part of
the interosseous membrane ; 8, tibialis posticus ; 8’,
its tendon, passing between the flexor digitorum
communis and the tibia ;.9, flexor digitorum com-
munis ; 9’, its temlon, with that of the tibialis pos-
ticus, passing behind the malleolus internus ; 10,
flexor longus pollicis ; 10’, placed beside its tendon,
where it passes over the tibia and astragalus ; 11,
peroneus longus ; 11’, its tendon behind that of the
peroneus brevis, passing down behind the malleolus
externus ; 12, peroneus brevis.

Itelutions.—The soleus rests upon the flexor
longus pollicis, flexor longus digitorum, and
tibialis posticus muscles, together with the pos-
terior tibial vessels and nerve, from which. how-
ever, it is separated by the deep aponeurosis.

Varictics—VTo the soleus an accessory por-
tion is occasionally added at its lower and inner
part ; this usually ends on the inner side of the
tendo Achillis, but it sometimes forms a tendon,
attached separately to the os calcis.

The tendo Achillis. the thickest and
strongest tendon in the kody, is formed by
the union of the flat tendon of the gastro-
cnemius with the thicker and more rounded
tendon of the soleus. It is from three to
four inches long below the point where the
muscular fibres of the soleus cease to be
attached to it. It is inserted inferiorly into the back part of the
tuberosity ot the os calcis. A synovial bursa is interposed between the
upper part of the tuberosity of the os calcis and the tendon.

x.

S ]ij f
Pilibvinn Nee

252 MUSCLES OF THE LOWER LIMB.

The plantaris muscle arises from the femur immediately above the
external condyle, and from the posterior ligament of the knee-joint ;
its muscular part is from three to four inches in length, and terminates
in along delicate tendon, which inclines inwards between the gastro-
cnemius and soleus, and, running along the inner border of the tendo
Achillis, is inserted not far from it into the posterior part of the caleaneum.

Varicties——The plantaris varies in its mode of termination ; it is sometimes
enclosed in the lower part of the tendo Achillis ; and, in other cases, it ends in
the internal annular ligament, which binds down the tendons and vessels behind
the inner malleolus. It isnot unfrequently absent altogether. This muscle, which
is little developed and almost vestigial in man, is sometimes of large size in
animals, and in some is continued forward in the sole of the foot as a part of the
flexor muscles of the toes,

The DEEP GROUP of posterior muscles of the leg is in close contact
with the bones ; it consists of the popliteus, flexor longus digitorum,
flexor longus pollicis, and tibialis posticus.

The popliteus, an oblique muscle placed below the knee, arises by a
thick tendon, about an inch in length, from the fore part of the
popliteal groove on the outer surface of the external condyle of the
femur, within the external lateral ligament and capsule of the knee-joint ;
it is in contact with the external semilunar cartilage, and receives
additional fibres from the posterior ligament of the joint. The mus-
cular fibres diverge as they pass downwards, and are inserted into
the triangular surface of the tibia above the posterior oblique line.

‘he tendon of the popliteus muscle occupies the groove on the outside
of the femur in flexion only.

Relations.—The popliteus is bound down by an aponeurosis, principally derived
from the tendon of the semimembranosus muscle. The plantaris and gastro-
cnemius muscle, the popliteal vessels and internal popliteal nerve lie upon its
posterior surface.

The three remaining muscles of this group are bound down together
by a deep fascia, which extends between the tibia and fibula, and sepa-
rates them frem the soleus.

The flexor longus digitorum pedis muscle, or flexor perforans,
arises from the posterior surface of the tibia, in a space extending from
the oblique line to within three inches of the inner ankle; it likewise
arises In connection with the flexor longus pollicis, by aponeurotic fibres,
which pass over the surface of the tibialis posticus. Its tendon descends
in a groove behind the internal malleolus, lying on that of the tibialis
posticus, and invested by a distinct fibrous and synovial sheath ; it is
then directed under the arch of the os calcis, obliquely forwards and
outwards, into the sole of the foot, crossing the tendon of the flexor
longus pollicis inferiorly, and connected with it by a tendinous slip ; it
then divides into four parts, which pass forwards to be inserted into
the terminal phalanges of the four smaller toes. Each digital tendon
enters a fibrous sheath on the toe to which it belongs, perforates the
corresponding tendon of the flexor brevis digitorum, and is invested
with synovial membrane, and connected by vincula accessoria to the
phalanges; the whole arrangement being essentially the same as that
which has been already described in the fingers.

Relations —It rests upon the tibia and upon the inner surface of the tibialis
posticus, the tendon of which it also crosses about two inches above the ankle.

FLEXOR MUSCLES OF THE FOOT. 253

It is covered at the upper part by the soleus and inferiorly by the aponeurosis of
the leg. Upon it also lie the posterior tibial vessels and nerve.

Varieties —A second head of origin has not unfrequently been found. This
may arise from the outer tuberosity of the tibia, or from the fibula, or from the
fascia of the leg. This second head has been seen joining the accessorius or even
replacing it (Otto). Gies describes an accessory slip from the tibialis anticus,
which joined the flexor digitorum at the ankle. A flexor digiti secundi pronrius
was found by Bahnsen, arising from the back of the tibia.

Fig. 196.—Szconp Layer or Puantar Muscrzs.

1, tendon of the flexor longus pollicis muscle, emerging
behind from its sheath below the sustentaculum tali, and
passing deeper than, 2, the tendons of the deep common flexor ;
3, two heads of the flexor accessorius ; 4, the four lumbricales ;
5, tendon of the flexor brevis cut short and seen splitting to
allow the passage through it of the tendon of the long flexor ;
6, flexor brevis pollicis ; 7, flexor brevis minimi digiti ; there
is also represented on the outer side of the foot the tendon of
the peroneus longus winding round the cuboid bone.

Intimately connected with the tendon of the
flexor longus digitorum are the flexor accessorius
and the lumbricales muscles, which, although they
occupy the foot, maybe most conveniently de-
scribed in this place.

The flexor accessorius arises by two heads,
the internal and larger of which is fleshy, and is
attached to the inner surface of the calcaneum,
while the external, flat, narrow, and tendinous,
is attached to the plantar surface of the cal-
caneum a little in front of the external tubercle,
and to the ligamentum longum plant. Those
origins united form a muscular mass which is inserted into the
external border end upper and lower surfaces of the tendon of the flexor
longus digitorum.

The lumbricales muscles, four in number, arise from the tendons of
the flexor longus digitorum at their point of division, each being, with
the exception of the most internal, attached to two tendons. They
pass forward to the inner sides of the four outer toes, each muscle ending
in a tendon, which is inserted into the expansion of the extensor tendon
on the dorsum of the first phalanx of the toe.

Relations.—In the sole of the foot the tendons of the flexor longus digitorum,
together with the flexor accessorius and the lumbricales, are covered below by
the flexor brevis digitorum; the plantar nerves and hinder part of the external.
plantar artery being placed between. These tendons, with their additional mus-
cles, conceal the adductor pollicis, the tendon of the flexor longus pollicis,
the transversus pedis, the interossei muscles, and the plantar arterial arch,

The flexor longus pollicis pedis, or flexor hallucis muscle, arises
from the lower two-thirds of the posterior surface of the fibula, except
for an inch at its lowest part ; from the intermuscular septum between
it and the peronei; and from the aponeurosis common to it and the
flexor longus digitorum, which covers the tibialis posticus. . The mus-
cular fibres, passing obliquely backwards and downwards, end in a
tendon on the posterior surface of the muscle. This tendon traverses
a groove on the lower end of the tibia, at the back of the astragalus and

254 MUSCLES OF THE LOWER LIMB,

the under surface of the sustentaculum tali, being bound down to those
bones by fibrous and synovial sheaths. Thence passing forwards and
inwards, in the sole of the foot, it gives off a tendinous slip to the
tendon of the flexor longus digitorum, by which it is crossed, and
proceeds in a fibrous sheath over the first phalanx of the great toe
to be inserted into the base of the terminal phalanx.

Relations —This muscle is concealed for the most part by the soleus, a small
part only at the outer side of the tendo Achillis being covered by the fascia of the
leg. Externally it is in contact with the peronei, and internally with the tibialis
posticus. It rests upon the fibula and conceals the peroneal vessels. Below the
ankle the tendon of this muscle is separated from that of the flexor longus digi-
torum by an interval of more than half an inch, in which are placed the pos-
terior tibial vessels and nerves. In the sole it is covered by the plantar fascia
and abductor pollicis muscle ; itis also crossed by the plantar vessels and nerves,
and the tendon of the long flexor of the toes. It rests upon the flexor brevis
pollicis.
Varietics—This muscle is liable to very few variations, but the mode of union
of its tendon with that of the flexor longus digitorum is exceedingly variable.
According to Turner, in no two subjects is it exactly similar. In almost every
ease the slip of union comes from the flexor pollicis, though in about one-sixth of
the cases an additional slip proceeds from the flexor digitorum to the flexor pollicis
(Turner, Wood). Complete separation of the tendons is very rare. This slip from
the flexor pollicis most frequently passes to the second and third toes but it may
pass to the second only, or to all the four outer toes.

The peronco-calcancus internus is a small muscle described by Macalister as the
probable homotype of the pronator quadratus of the arm. It arises below the
flexor longus pollicis from an oblique line on the back of the fibula, behind the
external malleolus, passes over the sustentacnlum tali in the groove with the
flexor pollicis, to be inserted into a tubercle of the os calcis (Muscular Anomalies,
p. 125).

Fig. 197. Fig. 197. —TransverseE Section of THE RicHr
Foot BETWEEN THE Tarsus AND METATARSUS.
Avs,

a, 6, c, articular metatarsal surface of the internal,
middle, and external cuneiform bones ; d and e, the
surfaces of the cuboid bone for the fourth and fifth
metatarsal bones ; between these bones are seen the
strong interosseous and plantar ligaments which
bind them together; 1, slip of the tendon of the
tibialis anticus, which passes on to its insertion on
the first metatarsal bone ; 2, tendon of the extensor
longus pollicis ; 3, slip of the extensor brevis digi-
torum to the great toe ; 3’, remainder of the ex-
tensor brevis digitorum ; 4, four slips of the ex-
tensor communis digitorum longus ; 5, peroneus
tertius ; 6, peroneus brevis; 7, peroneus longus cut obliquely where it is emerging from
its sheath below the cuboid bone; 8, tendon of the flexor longus pollicis ; 9, tendon of
the flexor communis digitorum longus, with the slip of union from the flexor pollicis ;
10, flexor accessorius ; 11, abductor pollicis; 12, flexor brevis digitorum ; 13, abductor
minimi digiti.

The tibialis posticus muscle, placed between the two long flexor
muscles, arises from the whole interosseous membrane except for two
inches at the lower end, and from the adjacent surfaces of the tibia and
fibula, the tibial attachment extending from the superior tibio-fibular
articulation to a point at a lower level than that of the flexor longus
digitorum, and the attachment to the fibula extending along the three
middle fifths of that bone; it also arises from the aponeurosis derived

PLANTAR FASCIA. 255

from the adjacent muscles, which covers it. The muscular fibres end
in a strong flat tendon, which, passing between the tibia and the long
flexor of the toes, turns forwards in a groove beneath the internal
malleolus, and is inserted into the tuberosity of the scapboid bone.

From its insertion, offsets of the tendon are prolonged forwards to
a.l the cuneiform bones, to the os cuboides, and to the bases of the
second, third, and fourth metatarsal bones; and one thin process is
directed backwards to the sustentaculum tali. The tendon is covered
by a synovial membrane behind the malleolus. Close to its insertion,
where it lies against tie astragalus, it contains a sesamoid fibro-
cartilage, which is occasionally converted into bone.

Relations.—The tibialis posticus is concealed in great part by the aponeurosis
prolonged over it from the muscles on either side. Superiorly, where it is not
covered by these muscles, it supports the posterior tibial and peroneal vessels.

Varicties.—These are rare. Several anatomists have described an occasional
muscle, which arises from the back of the tibia below the fiexor digitorum, and
is inserted into the capsule of the ankle-joint or into the ligamentum cruciatum.
This is the tensor of the capsule of the ankle-joint of Henle and Linhart, or the
tibialis secundus of Bahnsen.

Nerves.—The gastrocnemius, plantaris, soleus, and popliteus, are supplied with
branches from the internal popliteal nerve. The flexor longus digitorum, flexor
longus pollicis and tibialis posticus derive their nerves from the posterior tibial.

THE PLANTAR FASCIA AND MUSCLES,

The superficial fascia of the sole of the foot resembles that of the
palm of the hand. It forms a thick cushion, especially over bony pro-
minences, and consists mainly of small lobules of fatty tissue bound
down by numerous fibrous bands which pass vertically from the skin to
the deep fascia.

The deep plantar fascia, which is remarkably strong, is composed
of dense white glistening fibres, the greater number of which are
arranged in a longitudinal direction, and extend from the under surface of
the os calcis forwards to the heads of the metatarsal bones. It presents
a central and two lateral portions, clearly marked off from each other
by two strong intermuscular septa, indicated on the surface by grooves.
The iner portion, thinner and looser than the others, invests the
abductor pollicis, and is often partly removed with the skin in dissec-
tion. Itis continuous round the inner border of the foot with the dorsal
fascia and with the internal angular ligament. The owter part covers the
abductor minimi digiti, and is much stronger, particularly between the
outer tubercle of the caleaneum and the base of the fifth metatarsal bone,
between which points it forms a strong ligament. It is continuons
round the outer border of the foot with the dorsal fascia, and sends a thin
prolongation forwards over the insertion of the abductor and the short
flexor of the little toe. ‘The central portion, like the corresponding part
of the palmar fascia, is narrow behind, and becomes wider and thinner
towards the toes. At the back, where it is thickest, the fascia is
attached to the inner tubercle on the under surface of the caleaneum
immediately behind the origin of the flexor brevis digitorum, with
which muscle it is closely connected. Nearly opposite the middle of
the metatarsal bones, this fascia, becoming broader and thinner as it
advances, begins to divide into five processes, one for each of the toes ;
and trom this point forwards to the base of the toes, numerous strong

555 MUSCLES OF THE LOWER LIMB.

transverse fibres are superadded, which bind the processes together,
and connect them closely with the skin. Near the articulation of the
tees with the metatarsal bones, each of the five processes divides, to
permit the passave of the fiexor tendons ; and the two bundles of fibres
resulting from the division of each process, after strengthening the
sheath of the tendons over which they pass, are attached to the sides of
the metatarsal bone, and are blended with the transverse ligament
uniting those bones. From the point of splitting of each process, as in
the hand, fibrous bands are continued forwards to the skin in the
divisions between the toes.

The two ttermuscular septa which lie between the middle and
lateral portions of the plantar fascia pass deeply into the sole of the
foot ; they separate the flexor brevis digitorum from the abductor
pollicis on the inner side, and from the abductor minimi digiti on the
outer side, and give partial origin to each of these muscles.

In the sole of the foot as in the palm of the hand there is a band
of transverse fibres across the roots of the digits, placed immediately
beneath the skin, and connected with the subjacent sheaths of the
tendons. The digital nerves and vessels are covered by this structure,
which receives the name of transverse ligament of the toes.

Sxort PLAntaR Muscites.—These muscles may most conveniently
be described in layers, as they are found in the course of a dissection.
The jirst, or superficial layer includes the common flexor of the toes,
and the abductors of the great and little toes. The second layer consists
of the flexor accessorius and the lumbricales, the ¢hird layer of the deep
plantar muscles of the great and little toes, and the fourth layer of the
dorsal and plantar interossei.

Fig. 198, Fig. 198.— First Layer or Puantar Muscurs, AS SEEN ON

THE REMOVAL OF THE Prantar Fascia. 7

1, abductor pollicis ; 2, flexor brevis digitorum; on the
second toe the sheath is opened so as to show the tendon of
the flexor brevis perforated by that of the flexor longus ; on.
the other toes the transverse and oblique crossing fibres of the
sheath are shown; 3, strongest portion of the plantar
aponeurosis left upon the surface of the flexor brevis, near the
os calcis; 4, abductor minimi digiti; 5, the lumbricales
muscles ; 6, tendon of the flexor longus hallucis muscle.

I'Inst LAYER OF Muscies.—The flexor brevis
digitorum, or flexor perforatus, arises by a
small pointed and tendinous attachment from the
inner part of the greater tuberosity of the cal-
caneum, from the deep surface of the plantar
fascia for about two inches forwards, and from
the intermuscular septum on each side. The
muscle terminates in four slender tendons, in-
serted into the second phalanx of each of the four
outer toes. Each tendon prior to its insertion
divides and gives passage between its parts to the
tendon of the long flexor, in a manner precisely
similar to the arrangement of the tendons of the flexor sublimis and
flexor profundus muscles of the hand.

Relations.—This muscle lies between the abductor pollicis and abductor minimi

MUSCLES OF THE FOOT, 257

digiti, and is covered by the plantar fascia, which adheres very closely to the
posterior part of its surface, and gives origin there to some of its fibres; it
conceals the flexor accessorius, with the tendons of the flexor longus digitorum,
the lumbricales, and the plantar vessels and nerves.

Varictics—This muscle has been seen with only three tendons, that for the
little toe being absent ; or with five tendons, two to the second toe. The slip to
the little toe frequently arises as a small fusiform muscle from the side of the
long flexor tendon, or from the flexor accessorius ; or it may arise by two heads,
one from the long flexor, the other from the inner tubercle of the os calcis,

The abductor pollicis pedis muscle arises from the inner part of
the larger protuberance of the calcaneum, from the internal annular
ligament and the tendinous and fibrous structures on the inner border
of the foot as far forwards as the internal cuneiform bone, from the
septum between it and the flexor brevis digitorum, and from the plantar
fascia covering it. The fleshy fibres end in a tendon, which, after
uniting with the internal head of the flexor brevis pollicis, is inserted
into the inner border of the base of the first phalanx of the great toe.

felations.—It is covered by the thin internal division of the plantar fascia.
Its deep surface is in contact with the tendons of the tibialis anticus and pos-
ticus, and of the long flexor muscles, with the flexor brevis pollicis, and with the
plantar vessels and nerves.

Varietics—The abductor pollicis sometimes sends a slip to the base of the
first phalanx of the second toe. Another slip is occasionally given to the skin of
the ball of the great toe.

The abductor minimi digiti muscle has a wide origin behind,
from the front of both tubercles on the under surface of the os calcis,
from the external intermuscular septum, and from the deep surface of
tne process of the plantar fascia which extends from the external
tubercle to the base of the fifth metatarsal bone. The fleshy fibres
end in a tendon, which after sliding along a smooth impression on the
inferior surface of the base of the fifth metatarsal bone, is inserted
into the external surface of the base of the first phalanx of the little toe.

telations.—This muscle is covered by the plantar fascia. Its deep surface is
in contact with the external head of the flexor accessorius, the ligamentum
longum plant, the peroneus longus, and the flexor brevis minimi digiti.

Variety.—The abductor ossis metatarsi minimi digiti is an occasional muscle
which arises from the external tubercle of the os calcis, and is inserted into the
spur-like process of the fifth metatarsai bone beneath the outer margin of
the plantar fascia. It may be adherent to the abductor minimi digiti, and it has
been seen inserted into the middle or even the anterior part of the metatarsal
bone. It was first described as a human muscle by Wood, and it occurs nearly
once in every two subjects. (Wood, Macalister.)

THE Seconp Layer or Muscies.—The flexor accessorius and the
lumbricales muscles composing this layer, have been already described
(p. 258) with the tendons of the long flexor muscles, with which they
are intimately associated.

Tue TuirD Layer or Muscies.—The flexor brevis pollicis pedis
arises by a flat tendinous process from the inner border of the cuboid
bone and from the fibrous band sent to the cuneiform bones from the
tendon of the tibialis posticus. The muscle is single and pointed
behind, but in front it divides so as to form two muscular bellies
which are inserted by tendons one into the inner border of the base of
the first phalanx in union with the abductor pollicis, the other into the

outer border in union with the adductor.
WOlen Is 8

258 MUSCLES OF THE LOWER LIMB.

Relations —The tendon of the flexor longus pollicis runs in the interval
between the heads of the short flexor. A sesamoid bone is developed in connec-
tion with each tendon of the short flexor.

Fig. 199. Fig. 199.—Tarrp Layer or Prantar Muvscuzs.

1, flexor brevis pollicis ; 2, adductor pollicis ; 3, transversus
pedis ; 4, flexor brevis minimi digiti ; 5, 5, part of the third
and fourth dorsal interossei ; 6, 6, the second and third plantar
interossei ; 7, tendon of the peroneus longus passing round
the cuboid bone to enter its groove ; 8, long plantar ligament
passing forwards to the ridge of the cuboid bones and spreading
over the groove of the peroneus tendon.

The adductor pollicis pedis, placed obliquely
in the sole of the foot, and forming a thick fleshy
mass, arises from the tarsal extremities of the
third and fourth metatarsal bones, and from the
sheath of the peroneus longus muscle ; narrowing
as it passes forwards, it is inserted, conjointly
with the external head of the flexor brevis pollicis,
into the base of the first phalanx of the great toe.

Relations —At its inner side it is connected with the
flexor brevis pollicis; its deep surface rests upon the
second, third, and fourth metatarsal bones and the inter-
vening interosseous muscles. The external plantar artery
and nerve pass inwards beneath its outer border.

Varicty.—The opponens hailucis is a muscle frequently
found. It usually comes off as a slip from the adductor, and is inserted into the
metatarsal bone of the great toe. It occurs in some apes. (Macalister.)

The transversus pedis consists of narrow fasciculi of fleshy fibres,
placed transversely under cover of the flexor tendons, and arising from
the inner lateral metatarso-phalangeal ligaments of the four outer toes.
The fibres of the muscle pass transversely inwards, and are inserted in
union with the adductor pollicis into the first phalanx of the great toe.

Relations.—Superficially it is crossed by the flexor tendons and by the digital
nerves ; its deep surface rests upon the heads of the second, third, and fourth
metatarsal bones, the interossei muscles and the digital vessels.

Variety.—The slip from the little toe is frequently absent : absence of other
slips or of the entire muscle has also been recorded. (Boehmer.)

The flexor brevis minimi digiti arises by tendinous fibres from
the base of the fifth metatarsal bone, and from the sheath of the pero-
neus longus, and terminates in a tendon which is inserted into the base
and external border of the first phalanx of the little toe.

Relations.—It is covered partly by the abductor minimi digiti, partly by the
plantar fascia. Itrests upon the fifth metatarsal bone, and its tendon blends at
its insertion with the inferior metatarso-phalangeal ligament.

Varicty.—The opponens minimi digiti is a small additional muscle frequently
found at the inner border of the flexor brevis, of which, indeed, it would seem
to be aslip. It is always united to the flexor brevis for some distance from its
origin, but is inserted separately into the inner side of the anterior half of the
fifth metatarsal bone.

Tue Fourra Layer or Muscius.—The interosseous muscles of
the foot, like those of the hand, are seven in number, three plantar and
four dorsal ; the plantar interossei are visible only from the under side :

ACTIONS OF THE MUSCLES OF THE LEG AND FOOT. 259

the dorsal muscles are visible both from above and below. ‘Two muscles
are found in each space, except the innermost, in which there is only one.

Fig. 200, A.—Tur Dorsat IntTKROSSEOUS Fig. 200.

MUSCLES FROM ABOVE. j A

1, 2, 3, 4, the several dorsal inter-
osseous muscles : the final insertion of
the extensor tendons into the phalanges
of the toes is also shown in this figure.

B.—Tur Priantar InreRosszous Mvs-
CLES FROM BELOW.

1, 2, 3, the three plantar interossei ;
this figure also shows the long and short
plantar ligaments, and the insertion of
the tendon of the peroneus longus mus-
cle into the first metatarsal bone.

The dorsal interossei lie one
in each interspace. Each muscle
arises by two heads from the ad-
jacent sides of two metatarsal
bones ; their muscular fibres are
attached pennately on the two
sides of a central tendon which
is inserted partly into the dorsal
surface of the first; phalanx and
partly into the extensor apo-
neurosis of the toe to which each belongs. The first two are inserted
one on each side of the second toe ; the third and fourth are severally
inserted on the outer sides of the third and fourth toes. At the proximal
ends of each muscle there is an interval between the two origins
giving passage to perforating arteries as in the hand.

The plantar interossei arise from the inner and under surfaces of the
third, fourth, and fifth metatarsal bones, and are severally inserted in
a manner similar to the dorsal interossei, partly into the inner sides of
the first phalanges of the third, fourth, and fifth toes, and partly into
the extensor tendons of these toes.

Nerves.—The flexor brevis digitorum, the abductor, the flexor brevis pollicis,
and the two inner lumbricales, are supplied by the internal plantar nerve; all
the other plantar muscles, including the flexor accessorius and the interossei, are
supplied by the external plantar nerve,

Actions of the Muscles of the Leg and Foot.—There is only one muscle of the
leg, viz., the popliteus, which acts on the knee-joint alone. Its principal action is
that of a rotator inwards of the lower leg ; and it is interesting to observe that,
while inward rotation of the leg at the knee-joint occurs only in flexion, it is
in that position only that the tendon of the popliteus lies in its groove on the
femur.

It may here be observed that owing to the difference in the direction of the
bend at the ankle, as compared with that at the wrist-joint, some confusion is
apt to arise in the description of the action of the muscles of the leg upon the
foot. As it is obvious from morphological considerations, that the anterior sur-
face of the leg and the dorsal surface of the foot belong to the general extensor
surface of the limb, corresponding with the back of the forearm and the dorsum
of the hand ; and that the back of the leg and the sole of the foot belong in the
same way to tke general jlexor surface corresponding with the front of the fore-

s 2

2.0 MORPHOLOGY OF THE LIMB MUSCLES.

arm and the palm of the hand, the foot being in a position of over-extension, it
follows that the muscles on the anterior aspect of the leg are really extensors,
and that their action in moving the foot so as to approximate the toes to the
front of the leg merely increases the over-extension ; while, on the other hand,
the muscles on the posterior aspect of the leg are really flexors, and their action
in straightening the ankle-joint is to reduce merely this over-extension by an
opposite movement of flexion. Nevertheless, it has been customary to apply the
name of flexion to the action of raising the foot on the front of the leg, and that
of extension to its depression. In the following description the usual terms are
employed.

The gastrocnemius muscle acts both as a flexor of the knee and an extensor of
the ankle-joint. When the anterior muscles of the leg fix the ankle-joint, it is
fitted to act as a flexor of the knee; when the knee is fixed either by being
placed in complete extension or by the sustained action of the extensor muscles,
the gastrocnemius acts entirely on the foot, and combines with the soleus in
lifting the heel from the ground, and in raising the body on the toes,

The tidialis anticus and peroncus tertius are flexors of the foot; the tibialis
posticus and peroncus longus and brevis are extensors. ‘The two tibial muscles acting
together, raise the inner border of the foot, and draw it inwards. The three
peronei muscles raise the outer border of the foot and draw it outwards. The
peroneus longus, in crossing the foot inferiorly, strengthens the transverse arch
formed by the metatarsal bones and anterior range of tarsal bones ; especially
when that arch is pressed upon by the weight of the body falling on the balls of
the toes, as in stooping with bended knees.

The fleror and extensor muscles of the toes, including the lumbricales and
intcrossci, act like the corresponding muscles in the hand. The direction of the
flexor longus digitorum is, however, modified by the flexor accessorius, so as to
bring its line of action into the direction of the middle of the foot and of the
short flexor. The flexor accessorius and tendon of the long flexor muscles,
likewise assist the short flexor and the plantar aponeurosis in maintaining the arch
of the foot,

MORPHOLOGY OF THE LIMB-MUSCLES.

It has already been mentioned (p. 185) that the muscles of the limbs and limb
girdles are primarily derived mainly from the ventro-lateral division of the
epaxial set of muscles. In the case of the upper limbs there are no muscles of
hypaxial origin, but in the lower limb there are at least two muscles which may
be regarded as prolongations outwards from the hypaxial set, one passing to its
inner and anterior (preaxial) aspect (psoas), the other to its posterior and outer
(postaxial) aspect (pyriformis). These two muscles are consequently without
homologues in the upper limbs. As each limb begins bud-like to project from
the side of the embryo, it may be supposed to receive an enveloping sheath of
muscle from the side of the body (Humphry). This sheath is at first a simple
infundibulum, but it gradually extends in length with the growth of the limb,
and becomes segmented, pari passu, with the segmentation of the hard parts.
The deeper fibres of the sheath are restricted to passing from one segment to the
next, while the superficial fibres are frequently found to pass over one segment
altogether, to the more distal parts. Humphry holds that of the three layers
into which the trunk portion of the ventro-lateral muscle divides, two layers
may be traced into its appendicular segments, corresponding respectively to the
external oblique and superficial portion of the internal oblique layers. In the
upper limb, from the greater freedom of movement of the girdle, and from its
more superficial position, the first segment of the muscular sheath is longer, and
its constituent parts more easily recognised, than in the case of the trunk-girdle
muscles of the lower limb, which are not differentiated to the same extent from
the trunk muscles. Traced to the shoulder-girdle, the superficial layer of trunk-
limb muscles is found to divide into three principal masses. Anteriorly are the
pectorals ; superiorly and posteriorly are the cleido-mastoid and trapezius, the
latter being continued to the bone of the forearm as the deltoid ; and inferiorly
and posteriorly the latissimus dorsi, Beneath the trapezius are the rhomboids,

MORPHOLOGY OF THE LIMB-MUSCLES. 261

and on the deeper surface of the latissimus dorsi are its occasional scapular por-
tion and the teres major, all of which are formed in the deeper parts of this
layer. The muscles of this layer are frequently found to some extent united
together either as varieties in man, or as regular structures among some of the
lower animals, and it is interesting to note that most of the varieties hitherto
described, seem to be reversions so far towards a uniform type. Thus in Lepi-
dosiren, the pectoralis major and latissimus dorsi are blended together at their
margins, so as to form one continuous muscle ; and in man the frequently recur-
ring axillary arches or loops of muscular fibres which pass from one muscle to
the other across the axillary space may point to an imperfectly sezmented condi-
tion. Again, the pectoralis major is always united in man with the superficial
fibres of the external oblique, but in the cryptobranch it is continuous with it in
its entire thickness. The cleido-mastoid, which in man is in close relation with
the clavicular portion of the pectoralis major, being only separated from it by
the clavicle runs with the anterior part of the trapezius into the deltoid in those
animals in which the clavicle is deficient, forming a mastoido-humeral muscle.

The trunk-limb muscles of the deep layer, form a much less complete layer
than those of the superficial. They are attached to the shoulder-girdle in two
sets. In front of the glenoid cavity, and attached to the coracoid, is the costo-
coracoid muscle (in man called subclavius from its more common place of
attachment); and behind the glenoid cavity, attached to the scapula, are the
costo-scapular muscles, comprising the serratus magnus, and the levator scapule,
Besides these there is the slender omo-hyoid from the front of the hyoidean arch
to the upper border of the scapula.

Im the lower limb the ventro-appendicular muscles are represented for the
most part by the oblique abdominal muscles, only those muscles which pass over
the girdle to the limb being found distinct. The gluteus maximus most closely
represents the latissimus dorsi, and is similarly inserted into the postaxial border
of the limb. The pectoralis corresponds most nearly with the gracilis, and the
trapezio-deltoid with the anterior part of the external oblique and pectineus.
The gracilis and pectineus arise near each other, and are inserted into the pre-
axial border of the limb. The pectineus, however, seems to consist of two parts,
of which the inner may be related to subclavius, and the outer to great pectoral
and deltoid.

All the other muscles of the limbs are intrinsic, and in their relation to the
several segments are arranged in groups which may in the main be compared
homologically with each other. These groups are situated chiefly on the ventral
and dorsal aspects, or on the preaxial and postaxial borders of the limbs, and the
muscles of which they are composed are respectively flexors and extensors, or
protractors and retractors.

In attempting, however, to institute a homological comparison between the
individual muscles of the various segments in the two limbs, it will be necessary
to bear in mind, first, the great difference in the attitude of the bones of the
proximal segments, the flexor surface in the upper limb being thrown forwards
as if by an outward twist, and in the lower limb the flexor surface being twmed
backwards as if by an inward twist of the proximal segments; and further, the
preponderance in the second segment of the lower limb of the preaxial bone
(tibia) over the postaxial (fibula) as opposed to the greater development of the
upper end of the postaxial bone of the arm (ulna) over the preaxial (radius).
These differences are apt to lead to confusion and difficulty, inasmuch as the
insertions of homologous muscles are in some cases very different in the two
limbs. Im such cases the determination of the homologies may be greatly
assisted by the observation of the more constant origins. For example, the
great extensor of the forearm is inserted into the postaxial ulna, while in the
leg the quadriceps is inserted into the preaxial tibia; and yet few will doubt
the justness of the homological comparison between them.

In the distal segments of both limbs the muscles, though more numerous,
become shorter and more uniform in their disposition, and hence the homology
becomes more apparent between the muscles of the hand and foot, than in those
situated nearer the root of the limbs.

262 COMPARISON OF THE LIMB-MUSCLES.

From what has been said it appears that considerable difficulty still prevails
in the determination of the muscular homologies of the upper and lower limbs,
especially in their proximal segments and attachment to the trunk, and the com-
parison of these muscles cannot, therefore, be minutely followed out. But the
following table may be useful to the student of human anatomy, as presenting
what appear to be the most probable views of the muscular relations in the upper
and lower limbs, and as indicating the bearing upon such views of some facts in
comparative anatomy as well as of some of the varieties mentioned in the pre-
vious description of the individual muscles. (Upon this subject consult the works
of Humphry, Mivart, Rolleston and Huxley, previously quoted in the Osteology.)

TABLE OF MUSCULAR HOMOLOGIES IN THE UPPER
AND LOWER LIMBS.

I, MUSCLES PASSING FROM TRUNK TO LIMBS OR THEIR GIRDLES,

Upper Limb* Lower Limb,
1. Trapezius . 1. Lumbar aponeurosis, &e.

la. Cleido-mastoid and aleetire mastoid )
1). Rhomboids ;

2. Levator scapule ) 9 a}
; j : +2

la, b. External oblique.

Internal oblique.
Transversalis.

2a. Serratus magnus |.
7 2) ) Quadratus Lumborun.

3. Latissimus dorsi ) 3. Gluteus maximus.

3a. Teres major a x . 3a. Tensor vaginze femoris.

4, Pectoralis major . : 2 2 4. Gracilis. Part of pectineus ?
4a. Pectoralis minor . 3 4 : da. Coccygeus. ?

4b. Subclavius (second pectoral of

pi ouaolientam supplied by obturator nerve

4b, Inner or deep head of Pectineus,
(Rolleston ) ?

5, Omohyoid . : ; : : 5.2?

II. MUSCLES PASSING MAINLY FROM GIRDLE TO LIMB.

Ga. Scapular part . 6a. Sartorius,
6. Deltoid 6b, Clavicdiay part. il Pectineus, outer head. supplied by
anterior crural nerve (Rolleston).
7. Supra spinatus . : , ¢ 7. Obturator internus ?
7a, Infra spinatus . ; : : Ta. Iliacus.
7b. Teres minor : : : : 7b. Lliacus minor (Luschka).

9 #5 { Gluteus medius.
8. Subscapularis 8. ) Gluteus minimus
9. Coraco-brachialis

a,b,c. Upper, middle and lower

parts

9a, b,c. Three adductors, with perhaps
obturator externus.

Ses head of Biceps fe-
moris.
Semi-membranosus.

{ Semi-tendinosus,

10. Biceps flexor cubiti
a. Scapular head
b. Coracoid head

ec. TLumeral head
10d. Brachialis Anticus

10a, d.

RADE Og oh

10c. Femoral head of Biceps femoris.

11. Triceps extensor cubiti : . 11. Quadriceps extensor cruris.
a. Seapular head. : a. Rectus femoris.
6, External humeral head ; db, Vastus externus.
c. Internal humeral head 3 ; Wastun jnberes:
Crureus.

* The numbers affixed to the several muscles in the two columns are intended merely
as a means of facilitating the reference from one to the other, the upper limb being taken
as the standard of comparison. The names of muscles printed in italics are those of
varieties more or less frequently found in human anatomy.

COMPARISON OF THE LIMB-MUSCLES. 263

Til. MuscLES PASSING OVER ELBOW AND KNEE JOINTS AND ACTING ON THE
RELATIVE POSITION OF THE BONES OF THE FOREARM AND LOWER LEG.

Upper Limb.

11. Supinator radii longus - :
12. Supinator radii brevis A °
13. Pronator radii teres . : :
14. Pronator quadratus . :

IV. MUSCLES PASSING OVER WRIST AND

Lower Limb,
LES ae
Ds
13. Popliteus.
14, Peroneo-caleancus internus (Mac-
alister. )

ANKLE JOINTS.

A. To the carpus and metacarpus or to the tarsus and metatarsus.

15. Extensor carpi radialis longior .)

15a. Extensor carpi radialis brevior
15). Extensor ossis metacarpi pollicis .

16. Extensor carpi ulnaris
17. Flexor carpi radialis
18. Flexor carpi ulnaris

ON

15. Tibialis anticus,

156. Extensor ossis metatarsi hallucis,
or with the preceding muscle.

16, Peroneus tertius,

17. ‘Tibialis posticus.

18. Peroneus brevis, and in part
muscles of the calf.

19. Peroneus longus,

B. Zo the digital phalanges,

20. Extensor com. digit. longus 5
20a. Extensor secundi internod. poll. .
21a. Extensor primi internod, poll.
21). Extensor indicis . -

21c, Extensor minimi digiti :

22. Flexor digitorum profundus
22a. Flexor longus pollicis

23. Flexor digitorum sublimis .
24. Palmaris longus.

VY. MUSCLES CONFINED TO

internodii pcllicis, indicis, and
minimi digiti .

26. Abductor pollicis

27. Flexor brevis pollicis, inner head
a. outer head

27b. Opponens pollicis

28. Adductor pollicis

yp Peneons of extensores =i
25

29. Tendons of flexor profundus digi-

torum ‘
30. Palmaris brevis . : 3
31. Abductor minimi digiti . A

32. Flexor brevis minimi digiti

33. Opponens minimi digiti

34. Interossei, dorsal and palmar .

Radialis secundi digiti (dors.)

Ulnaris sec. dig. (talm_)

Radialis medii (dors,) .

Ulnaris medii (dors.) .

Radialis quarti (palm.)

Ulnaris quarti (dors.) . :

Radialis quinti (palm.)

35. Lumbricales quatuor, radiales sec,
tert. quart. et quint. digit, : ;

Seay OcS PSS

20. Extensor com. digit. long.

20a. Extensor long. hallucis.

2la. First slip of ext. brevis digit.

21b. Second slip of ext. brevis digit.

21e. Occasional slip of peroneus ter-
tius,

22, Flexor digitorum longus,

22a. Flexor longus hallucis.

23. Flexor digitorum brevis.

24, Plantaris, and flexors ?

THE HAND AND Foot,

25. Extensor communis

brevis.

26. Abductor hallucis.

27. Flexor brevis hallucis.

27a, Adductor hallucis obliquus.
27b. Opponens hallucis.

28. 'Transversus pedis.

digitorum

29, Flexor communis digitorum brevis

30. ?
31. Abductor quinti digiti.
32. Flexor brevis quinti digiti.
33. Opponens quinti digiti.
34. Interossei, dorsal and palmar.
a, Tibialis secundi digiti (dors.)
b. Fibularis sec. dig. (dors. )
ec. Tibialis tertii (plant.)
d, Fibularis tertii (dors.)
e. Tibialis quarti (plant.)
7. Fibularis quarti (dors.)
q, Tibialis quinti (plant. )
35, Lumbricales quatuor, tibiales scc
tert, quart. et quint. digit.

264 MUSCLES OF THE HEAD AND NECK.

III. MUSCLES AND FASCIZ OF THE HEAD AND NECK.
EPICRANIAL REGION.

Fascra.—The superficial fascia is little developed on the head and
neck generally, and is in great measure blended with structures described
under other names. A layer of considerable firmness, lowever, inter-
venes between the aponeurosis of the occipito-frontalis muscle and the
skin, uniting them together: from the surface of the occipital part of
the muscle it becomes continuous with a superficial covering of the
posterior muscles of the neck, and on each side of the epicranial apo-
neurosis it descends over the temporal fascia, and contains between its
laminee the external muscles of the ear, with the superficial temporal
vessels and nerves.

Muscies.—Under the title of occipito-frontalis muscle are compre-
hended the occipital and frontal muscles, united together by a thin
aponeurosis which extends over and covers the upper part of the
cranium,

The occipitalis muscle, thin and subcutaneous, is attached infe-
riorly by short tendinous fibres to the external two-thirds, sometimes
less, of the superior curved line of the occipital bone, and to the mastoid
portion of the temporal bone, immediately above the attachment of the
sterno-mastoid muscle. Its fleshy fibres, from one to two inches in
length, are directed upwards, and terminate in distinct tendinous fibres,
continuous with the epicranial aponeurosis. ‘The interval between the
muscles of opposite sides is occupied by the aponeurosis.

The froutalis muscle, larger and of a paler colour than the occi-
pitalis, arises superiorly in a convex line from the epicranial aponeurosis,
while inferiorly its innermost fibres are continuous with the pyramidalis
nasi muscle; some take attachment to the internal angular process of
the frontal bone, and the others are blended with the corrugator
supercilii and with the orbicularis palpebrarum as far as the outer side
of the orbit. The fibres are nearly vertical, running slightly inwards;
the margins of the right and left muscles are united for a short dis-
tance above the root of the nose, but are separated by an angular
interval superiorly.

The epicranial or occipito-frontal aponeurosis extends over the
upper surface of the cranium uniformly from side to side, without
division. Posteriorly it is attached to the occipitales muscles, and to
the protuberance and superior curved lines of the occipital bone, and
anteriorly it terminates in the frontales muscles, while laterally it pre-
sents no distinct margin, but below the temporal ridge becomes thinner
and less aponeurotic, and gives attachment to the superior and anterior
auricular muscles. Its fibres are chiefly longitudinal, and are most
distinctly tendinous where they give attachment to the occipitales
muscles. Its outer surface is firmly bound to the skin by an abundant
network of connective tissue, constituting the so-called superficial fascia,
by the meshes of which the subcutaneous fat is divided into granules ;
while its deep surface glides upon the subjacent pericranium, to which
it is loosely attached by a delicate connective tissue devoid of fat.

Varictics—Both parts of the occipito-frontalis muscle are subject to variation in
their fulness or extent, and in their places of attachment. The occipitalis some-
times approaches the middle line, and is occasionally broken up into separate

EPICRANIAL AND AURICULAR MUSCLES. 265

parts. The frontalis has been found to send slips of attachment to the frontal;
nasal, or superior maxillary bones, and occasionally to the tendo oculi or to the
upper end of the levator labii superioris aleeque nasi.

A pair of symmetrical muscular slips is very frequently observed extending
outwards from the occipital protuberance, generally on the surface of the trape-
zius, but sometimes underlying that muscle, and inserted variously into the
posterior auricular or sterno-mastoid muscles, or into the outer part of the occi-
pital bone. This pair of muscular slips has received the name of transversus
nuche.

Actions.—By the contraction of the combined occipito-frontales muscles, the
scalp is drawn backwards, and the eyebrows elevated ; by the contraction of the
frontales muscles alone, the eyebrows are elevated, the scalp pulled forwards, and
the skin of the forehead thrown into transverse wrinkles ; by the contraction of
the occipitales muscles alone, the scalp is drawn backwards ; and by the alternate
action of the occipitales and frontales muscles the scalp is moved backwards and
forwards, In the majority of persons, however, there is only a partial control
over the action of these muscles, limited to the elevation of the eyebrows and
horizontal wrinkling of*the forehead.

AURICULAR MUSCLES

Besides minute bundles of muscular fibres which pass from one part
of the auricle to another, and which will be most conveniently described
along with that structure, there are attached to the external ear three
larger, but still very slightly developed, muscles, which serve to move it
as a whole.

The auricularis superior or attollens auriculam, the largest of
the three, arises in the temporal region of the head from the epicranial
aponeurosis. Its fibres are extremely delicate, and converge from a
wide surface to be inserted by a compressed tendon into the cartilage
of the ear at the upper and anterior part of the helix and upper part
of the concha.

The auriculavis anterior or attrahens auriculam, scarcely sepa-
rated from the preceding muscle, is pale and indistinct, and is attached
to the thin lateral prolongation of the epicranial aponeurosis, from
which it passes backwards to be inserted into the fore part of the
helix.

The auricularis posterior or retrahens auriculam muscle, con-
sists of two or three fasciculi, which arise from the mastoid process by
short aponeurotic fibres, and are inserted into the back part of the
concha. The fibres are deeper in colour and more distinctly marked
than in either of the other auricular muscles.

Varictics—Of the auticular muscles the posterior and the anterior are subject
to greater varieties than the superior, but all vary somewhat in the extent of
their development, the posterior more frequently by an increase in the number
of its slips, the anterior by a diminution of the volume and distinctness of its
fibres. The posterior fibres of the attollens have been observed continued back
into the occipitalis.

Actions.—The three auricular muscles respectively draw the pinna of the ear
upwards, backwards, and forwards. In the majority of persons their action is
not directly under voluntary control.

MUSCLES OF THE EYELIDS AND EYEBROWS.

These are four in number—namely, the orbicularis palpebrarum

and tensor tarsi, the levator palpebree superioris, and the corrugator
supercilil.

256 MUSCLES OF THE HEAD AND NECK.

The orbicularis palpebrarum is a thin elliptical muscle closely
adherent to the skin, surrounding the fissure between the eyelids and
covering their surface, and spreading for some distance outwards on the
temple, upwards on the forehead, and downwards on the cheek. The

Fig. 201.

yy nh! WHEN are

16

Fig. 201.—Superrician View or THE Muscies oN THE LEFT SIDE OF THE HeEAD AND
Neck (slightly altered trom Bourgery), (A. T.) 4
a, epicranial aponeurosis ; 6, superior curved line of the occipital bone ; c, ramus of
the lower jaw ; d, lower edge of the hyoid bone; e, sternal end of the clavicle. 1,
frontal, and 1’, occipital part of the occipito-frontalis muscle ; 2, superior auricular
muscle; 2’, anterior auricular ; 3, posterior auricular in two fasciculi; 4, margin
of the orbicularis palpebrarum ; 5, pyramidalis nasi; 6, triangularis nasi ; 7, levator
labii superioris aleque nasi; 8, orbicularis oris ; 8’, its attachment #0 the columella
nasi, or depressor nasi ; 9, levator labii superioris, and close by it, zygomaticus minor ;
between + and 8, zygomaticus major ; and between the zygomatici, in shadow, is seen
4 portion of the levator anguli oris; 10, quadratus menti or depressor labii inferioris,

ee

MUSCLES OF THE EYELIDS. 267

11, triangularis oris or depressor anguli oris ; 12, levator menti; 13, on the masseter
is immediately above the risorius or upper horizontal fibres of the platysma myoides,
and a line from it points to the buccinator ; 14, platysma myoides ; 15, on the upper
part of the sterno-mastoid, points by a line to the posterior belly of the digastric
muscle ; 15’, the sternal tendon of the sterno-mastoid, a part of its clavicular portion
is seen near ¢: 16, trapezius ; 17, splenius capitis ; +, splenius colli ; 18, levator scapule ;
19, sterno-hyoid ; 20, omo-hyoid ; 21, pectoralis major, its pectoral part; 21’, its
clavicular part ; 22, deltoid.

fibres form neary concentre curves, and are attached by their extremities
at the inner angle of the orbit; 1st, to the edges and anterior surface of
the tendo palpebrarum ; 2nd, to the srface of the nasal process of the
superior maxilla, near the anterior margin of the lachrymal groove;
and 3rd, to the internal angular process of the frontal bone.

—elations—The palpebral portion of the muscle consists of thin, pae, and
slightly curved fibres situated in the eyelids, and which conceal the tarsal carti-
lages and the insertion of the levator palpebre superioris ; the orbicular portion,
more largely developed, rests on the cheek and margin of the orbit. Superiorly
this muscle conceals the corrugator supercilii, with which and the occipito-
frontalis it is intimately connected; inferiorly it covers the origin of the
elevators of the upper lip, part of the common elevator of the lip and nose, and
the lachrymal sac ; and externally it lies upon a part of the temporal fascia.

The tendon of the orbicularis muscle (tendo palpebrarum), at the
inner commissure of the eyelids, is a small white cord which is often ob-
scured by the fibres of the muscle, but is rendered apparent by drawing
the lids outwards. This tendon is about two lines in length, and half
a line in breadth, and is attached to the anterior margin of the lach-
rymal groove; thence it runs horizontally outwards to the inner com-
missure of the eyelids, where it divides into two thin fibrous lamelle,
which diverge, and terminate on the tarsal cartilages. One surface of
the tendon is subcutaneous ; the other crosses the lachrymal sac a little
above the centre, and from it a thin but firm fascia is given off, which
spreads over the lachrymal sac, and adheres to the margins of the
erooye which lodges it.

The tensor tarsi—(inusculus sacci lachrymalis, Horner)—consists
of very thin fibres resting on the fascia just mentioned. It is only a
deep portion of the inner marginal fibres of the ciliary part of the
orbicularis muscle : two slips, one from each eyelid, passing behind the
Jachrymai canals, unite on the hinder surface of the lachrymal sac before
reaching their attachment on the posterior margin of the lachrymal
g oove.

The corrugator supercilii is a small, deeply-coloured muscle,
narrower below than above, placed at the inner side of the eyebrow.
It arises from the inner extremity of the superciliary ridge of the
frontal bone; thence its fibres proceed outwards and a little upwards,
and end, at the middle of the orbital arch, by becoming blended with
those of the orbicularis and occipito-frontalis muscles.

felations.—This muscle crosses the supratrochlear branch of the ophthalmic
nerve and the accompanying vessels, as they emerge from the orbit. It rests
upon the frontal bone and is covered by the orbicularis and occipito-frontalis
muscles.

The levator palpebre superioris occupies the upper part of the orbit.
Tts tendon only is seen in the dissection of the upper eyelid, in which it
forms a broad fibrous expansion which curves downwards, and is

268 MUSCLES OF THE HEAD AND NECK.

SS

Rig. 202.—SupERricraAL AND DEEP VIEW OF THE MuscLEs or THE Heap AnD NECK,
FROM BEFORE (altered from Bourgery). (A. 1T.) §

On the left side, the platysma alone has been removed ; on the right side, portions of
the zygomatic arch and the clavicle, the superficial muscles of the cranium and face, the
masseter, trapezius, sterno-mastoid and pectoralis major muscles have been removed ; a,
right alar cartilage of the nose ; 6, upon the lobe of the right ear, points to the coronoid
process of the lower jaw ; c, the body of the hyoid bone ; d, symphysis of the lower jaw ;
¢, upon the subclavian groove of the first rib, lying in which is the cut end of the sub-
clavian artery ; f, the glenoid cavity of the scapula ; y, the right zygomatic arch separated
from the malar bone ; 2, upon the temporal ridge of the frontal bone ; 2, above the supra-
orbital ridge ; 1, frontalis muscle ; 2, superior auricular ; 2’, insertion of the anterior
auricular ; 3, corrugator supercilii ; 4, orbital portion of the orbicularis palpebrarum ; 4,
palpebral portion ; below 7, the expanded insertion of levator palpebre superioris in the
eyelid ; 5, pyramidalis nasi ; 6, insertion of the triangulares nasi on the dorsum of the
nose ; 7, levator labii superioris aleeque nasi ; 8, orbicularis oris of the left side ; 8’,
outer part of the same on the right side, the inner part being removed ; 9, levator labit
superioris ; +, zygomaticus minor; 10, zygomaticus major ; 11, depressor anguli oris ;

MUSCLES OF THE NOSE. 269

12, depressor labii inferioris ; d, points to the cut ends of the levatores menti ; 13, placed
on the left masseter, points to the buccinator ; 13’, buccinator, of the right side, a
portion of the parotid duct passing through the muscle; 14, levator anguli oris, seen
also on the left side behind the zygomaticus minor. The remaining references will be
given under the muscles of the neck.

inserted under cover of the orbicularis muscle into the anterior surface
of the tarsal cartilage. It will be described along with the muscles of
the orbit.

Varicties—The muscles of this group are not subject to great variation.
The external fibres of the orbicularis palpebrarum sometimes extend farther than
usual, and take more intimate attachment to the corrugator supercilii, or blend
with the zygomaticus minor or levator labii superioris, The tensor tarsi is not
unfrequently divided into two parts.

Actions.—The orbicularis palpebrarum closes the eyelids. In the ordinary
closure of the eye, it is chiefly the upper lid which moves, being depressed by the
superior half of the palpebral part of the muscle ; but in forcible closure both eye-
lids moye, and not only come together, but are drawn towards the nose, at the
same time that the eyebrows are drawn downwards and inwards, and the neigh-
bouring skin of the face thrown into wrinkles, the whole fibres of the orbicularis
being thus contracted and drawn towards the tendo palpebrarum. In these
circumstances the fibres which form the tensor tarsi, being contracted like the
others, compress the lachrymal sac, and prevent the introduction intoit of the lachry-
mal secretion from the conjunctiva. The corrugator muscles draw the skin of the
forehead downwards and inwards, producing longitudinal furrows, as in frowning.
The upper eyelid is supported by the levator palpebre, and droops when that
muscle is paralysed. On the other hand, paralysis of the orbicularis is attended
by an inability to close the eyelids.

>

MUSCLES OF THE NOSE.

Under this head may be conveniently grouped not only the com-
pressor naris and smaller muscles which act upon the nose alone, but
also the pyramidalis nasi which acts on the forehead, and the common
levator of the nose and lip.

The pyramidalis nasi, continuous with the innermost fibres of the
frontalis muscle, extends downwards from the root of the nose, over the
upper part of it, and terminates by a tendinous expansion in: connection
with the compressor naris muscle. The muscles of opposite sides,
united superiorly, diverge slightly as they descend.

The compressor naris, a thin triangular muscle, arises narrow and
fleshy from the canine fossa in the superior maxillary bone, and pro-
ceeding inwards, gradually expands into a thin aponeurosis, which is
partly blended with that of the corresponding muscle of the opposite
side, and with the pyramidalis nasi, and is partly attached to the
cartilage of the nose. It is concealed at its origin by the proper
elevator of the lip, and is crossed by the common elevator.

The levator labii superioris aleque nasi, the common elevator of
the lip and nose, lies alone the side of the nose, extending from the
inner margin of the orbit to the upper lip. It arises by a pointed
process from the upper extremity of the nasal process of the superior
maxillary bone, and, as it descends, separates into two fasciculi ; one of
these, much smaller than the other, becomes attached to the wing of
the nose, whilst the other is prolonged to the upper lip, where it is
blended with the orbicularis and the special elevator muscle. It is

270 MUSCLES OF THE HEAD AND NECK.

subcutaneous, except at its origin, where the orbicularis palpebrarum
overlaps it a little.

Fig. 203.—MuscLEs oF THE SIDE OF THE Nose AND

Urrer Lip. §

1, pyramidalis nasi ; 2, levator labii superioris aleeque

nasi; 3, compressor naris or triangularis; 4, levator

proprius al nasi anterior; 5, levator proprius ale nasi

posterior or dilatator ; 6, depressor ale nasi ; 7, orbicu-
laris oris ; 7*, naso-labialis.

The depressor alz nasi is a small flat
muscle which arises from the superior incisor
fossa, and is inserted into the septum and
posterior part of the ala of the nose. “The
external fibres curve forwards and downwards
to the ala.

Besides the muscles above described there
are other irregular and often indistinct fibres
which cover the small alar cartilages of the
nose. Of these the following may be dis-
tinguished.

The levator proprius ale nasi posterior, or dilatator naris pos-
terior, is attached to the margin of the ascending process of the
superior maxillary bone and the smaller (sesamoid) cartilages of the
ala nasi on the one hand, and to the skin on the other. Another set of
fibres, the levator proprius ale nasi anterior, or dilatator naris
anterior, is interposed between the cartilage of the aperture of the nose
and skin, to both of which it is attached. The musculus anomalus of
Albinus is a longitudinal muscular slip of more than an inch in length,
lying beneath the common elevator of the lip and ala of the nose, con-
nected by the lower end with the origin of the compressor naris, and
attached exclusively to the superior maxillary bone.

Varicties—The compressor naris is sometimes very slightly developed, or even
reduced to an aponeurotie condition. The dilators and depressor of the nostril are
also subject to considerable variations in strength and in the mode of their
attachment.

Actions.—The pyramidalis nasi muscle, being continuous with the frontalis,
is the means of giving that muscle a more fixed attachment to the dorsum of the
nose, and assists in drawing down the integument of the forehead, and in pro-
ducing wrinkles across the root of the nose ; it probably acts also as an opponent
to the compressor naris muscle. The compressor naris, acting along with its
fellow of the other side, depresses the cartilaginous part of the nose, and to some
extent also compresses the alee together. The actions of the other muscles are
sufficiently indicated by their names ; the dilatation of the als is perceptible in
natural inspiration, and is well marked in dyspneea.

MUSCLES OF THE LIPS AND MOUTH.

Around the orifice of the mouth are situated an orbicular muscle
with concentric fibres, and numerous other muscles, whose fibres con-
verge towards the aperture, viz., superiorly the common elevator of the
lip and nose already described, the proper elevator of the upper lip, the
elevator of the angle of the mouth and the zygomatic muscles, laterally
the risorius and buccinator muscles, and, inferiorly, the depressor of

MUSCLES OF THE LIPS AND MOUTH. 21
the angle of the mouth and that of the lower lip; and lastly, acting
indirectly on the lower lip, the levator menti.

The orbicularis oris muscle, or sphincter oris, consists of labial and
facial parts. The labial or marginal part occupies the red part of the lips,
and forms a slightly convex fasciculus of pale fine fibres which are free
from bony attachment, and can be traced from one lip to another round
the corner of the mouth. The facial part, thinner and wider than the
other, blends by its outer border with the several contiguous muscles
that converge to the mouth, and more particularly with the buccinator
muscle, the fibres of which are continuous with the deeper part of the
orbicularis. Besides those fibres it has others, msculi incisivd (Henle),
that are attached to the subjacent cartilage and bone; viz., in the
upper lip two bundles for each half; and in the lower lip one for
each. In the upper lip the outer slip, thin and weak, passes down-
wards, and is attached opposite the incisor teeth, close to the alveolar
edge of the upper jaw-bone ; while the other, thick and pointed, passes
upwards and is fixed to the septum of the nose. In the lower lip the
reinforcing fasciculus arises from the surface of the lower jaw, near
the root of the canine tooth, and external to the levator labii inferioris,
and passing directly outwards towards the angle of the mouth, its fibres
blend with the rest of the muscle.

Relations —The skin of the lips is closely connected to the inner part of the
orbicularis oris muscle, whilst over the outer part fatty tissue is interposed
between them. The deep surface is in contact with the mucous membrane and
the labial glands, as well as with the coronary arterial arch in each lip.

The levator labii superioris proprius muscle arises from the
superior maxillary bone immediately above the infraorbital foramen,
and from the adjoining surface of the malar bone ; it passes downwards
and a little inwards to be blended with the orbicularis and other mus-
cular fibres in the upper lip.

Relations.—At its origin this muscle is overlapped by the orbicularis palpe-
brarum, but its lower part is subcutaneous ; it partly conceals the levator anguli
oris and the compressor naris, and beneath it the infraorbital vessels and nerve
emerge from the canal of that name.

Varictics—This muscle is frequently united with the levator lab. sup. aleque
nasi. It is also commonly seen arising by two heads, the outer being attached to
the malar bone, or coming as a slip from the orbicularis palpebrarum.

The levator anguli oris, or musculus caninus, arises in the
canine fossa immediately below the infraorbital foramen, inclines down-
wards and slightly outwards, and is inserted into the angle of the
month, where it becomes blended with the fibres of the orbicularis,
zygomatici and depressor anguli oris.

Relations.—At its origin this muscle is concealed by the proper elevator of the
upper lijy; its anterior surface supports the infraorbital nerve and artery, which
separate it from the preceding muscle ; the posterior surface lies on the superior
maxilla and the orbicularis and buccinator muscles, with which and the depressor
anguli oris the fibres are blended.

The ZYGOMATICI are two narrow and subcutaneous fasciculi of mus-
cular fibres, extending obliquely from the most prominent part of the

cheek to the angle of the mouth, one being thicker and longer than the
other.

272 MUSCLES OF THE HEAD AND NECK.

The zygomaticus minor, a very small muscle, arises from the an-
terior and inferior part of the malar bone, and inclines downwards and
forwards to terminate by joining the outer margin of the levator labii
superioris; sometimes near the origin of that muscle. It lies internal
to the zygomaticus major, but distinct from it in its whole length.

The zygomaticus major, placed externally to the smaller muscle of
the same name, arises from the malar bone near the zygomatic suture,
from which it descends to the angle of the mouth, where it is continued
into the orbicularis and depressor anguli oris.

Varicties—The zygomaticus minor is frequently absent; or it may fall
short of the mouth, and be inserted into the fascia of the cheek. It may arise
wholly or in part from the orbicularis palpebrarum ; it has also been observed
joined to the zygomaticus major, or to the levator labii superioris, or even to the
outer fibres of the frontalis (Eustachius). It has frequently been found double.

The zygomaticus major has also been found double, or it may be double merely
at its origin, Sometimes it arises from the masseteric fascia below the zygoma.
(Macalister.}

The risorius, or smiling muscle (Santorini), is generally regarded as
a part of the platysma myoides. It consists of some very thin fasciculi,
which commence in the fascia over the masseter, or on the parotid
gland, and, extending transversely inwards in the fat of the cheek,
join the orbicularis and depressor anguli oris at the angle of the
mouth.

Varictics.—The risorius has been seen to arise from the integument over the
upper end of the sterno-mastoid (Hallet) ; from the zygoma (McWhinnie) ; from
the external ear (Albinus) ; and from the fascia over the mastoid process (Mac-
alister). It was found double and even triple by Santorini.

The lower and lateral part of the face receives a superficial muscular
covering fromthe facial part of the platysma myoides, which is in-
corporated with the muscles of the angle of the mouth and lower lip,
and passes along with the superficial fascia over the base of the jaw
into the cervical portion of the muscle ; while the anterior portion of
the cervical platysma, continuous externally with the facial, takes firm
attachment to the base of the jaw for a length of two inches or more
external to the symphysis.

The buccinator muscle consists of a flat and thin but strong set of
fibres in contact with the mucous membrane, and forming a consider-
able part of the wall of the mouth. It is attached by its upper and
lower margins to the outer surface of the alveolar parts of the maxillary
bones, opposite the molar teeth, and by its posterior margin to the
nteryyo-maxillary ligament, a narrow band of tendinous fibres, which
extends from the internal pterygoid plate to the mylohyoid ridge of the
lower jaw close to the last molar tooth, and is placed between the
buccinator muscle and the superior constrictor of the pharynx. From
these points the fibres of the muscle are directed forwards, approaching
each other, so that the muscle is narrowed and proportionally thickened
near the angle of the mouth, where it becomes incorporated with the
orbicularis. The fibres near the middle of the muscle cross each other,
those from above passing into the lower lip, and those from below into
the upper one ; but the higher and lower fibres are directed into the
corresponding lip without decussation.

Rciations—The buccinator is covered and supported by a thin fascia, which
is closely adherent to the muscular fibres; and is overlapped by the triangularis

MUSCLES OF THE CHEEK AND LIPS. 273

Fig. 204.

2

SS SX WS \ i! |

Fig. 204.—Drzp yinrw or THE MuscLEs OF THE LEFT SIDE oF HE Heap AND Neck
(modified from Bourgery). (A. 7.) 2

a, vertex of the head ; 6, superior curved line of the occipital bone; c, ramus of the.
lower jaw ; ¢’, its coronoid process ; d, body of the hyoid bone; ¢, sternal end of the clavicle ;
e’, acromial end ; f, malar bone divided to show the insertion of the temporal muscle ;
f’, divided zygoma, and external lateral ligament of the jaw ; g, thyroid cartilage ; h, placed
on the lobe of the auricle, points to the styloid process ; 1, temporal muscle ; 2, corrugator
supercilii ; 3, pyramidalis nasi; 4, lateral cartilage of the nose covered by the triangularis
nasi ; 5, levator labii superioris proprius ; 6, levator anguli oris ; 7, outer part of the
orbicularis oris, the part below the nose has been removed ; 8, depressor ale nasi ;
9, points to the buccinator muscle, through which the parotid duct is seen yassing ; 10,
quadratus menti; 11, levator menti; 12, 12, anterior and posterior bellies of the
digastric ; 13, stylo-hyoid muscle ; 14, mylo-hyoid; 15, hyo-glossus, between which
and 13, is seen a part of the stylo-glossus ; 16, sterno-hyoid ; 17, on the clavicle, indicates
the lower, and 17’, the upper belly of the omo-hyoid ; 18, sterno-thyroid ; 19, thyro-
hyoid ; 20, 21, on the sterno-mastoid muscle, point, the first to the middle, the second to
the lower constrictor of the pharynx ; 22, trapezius ; 23, upper part of the complexus ;
24, splenius capitis; 25, splenius colli; 26, levator scapule ; 27, middle scalenus ;
+, posterior scalenus ; 28, anterior scalenus.

VOL. I. le

274 MUSCLES OF THE HEAD AND NECK.

oris, by the terminal fibres of the platysma myoides, and by the masseter and
zygomatici, from which it is separated by a quantity of soft adipose tissue of
a peculiar character. Opposite the second molar tooth of the upper jaw, its
fibres give passage to the duct of the parotid gland.

The depressor anguli oris, or triangularis cris muscle, is broad
at its origin from the external oblique line of the lower jaw ; passing
upwards it is coliected into a narrower bundle, which is inserted into
the orbicularis at the angle of the mouth.

Relations —This muscle is covered by the skin, and at its insertion, by the
zygomaticus major, under which its fibres pass; it conceals part of the buc-
cinator and of the depressor of the lower lip.

Variety —The transversalis menti (Santorini) is a small band of muscular
fibres sometimes found arising from the inner border of the depressor, and
curving downwards and inwards below the chin towards the mesial line of the
neck.

The depressor labii inferioris, or quadratus menti muscle, arises
from the lower jaw by a line of attachment extending from near the sym-
physis to a little beyond the mental foramen; thence it ascends with
an inward inclination, unites with its fellow, and blending with the
orbicularis oris is inserted into the lower lip. Its fibres are intermixed
with much adipose matter.

The levator labii inferioris, or levator menti muscle, arises by a
narrow head from the incisor pit of the lower jaw, and, expanding in
a nearly vertical plane, is directed downwards, and slightly forwards
and inwards, between the depressors of the lower lip, to the integu-
ment of the chin.

Nerves.—All the superficial muscles of the face previously described receive
their motor nerves from one source, viz., the facial motor. or portio dura of the
seventh pair, twigs from this widely distributed nerve being sent even into
the occipitalis muscle. The expression of the passions by the varying state of
the skin of the forehead and eyebrows, the eyelids, nostrils and mouth, the
closure of the eyelids, the dilatation of the nostrils in breathing, and the move-
ments of the lips in the prehension of food and otherwise, together with the
movements of the scalp and external ear, when they are possible,—are all under
the influence of the facial nerve, which has thus been reckoned as a nerve of
respiration and expression.

Actions.—The orbicularis oris acting alone draws the lips together in both
the vertical and transverse directions. Acting in conjunction with the bucci-
nators it closes the lips, while at the same time they are elongated transversely.
Its facial portion acting alone projects the lips. The labial portion, when acting
in concert with the converging muscles, tightens the lips, one or both, against
the teeth. The convergent muscles each draw their oral points of insertion in a
direction corresponding to that of their muscular fibres. The common elevator
of the lip and nose and the upper part of the orbicularis oris act on both the
upper lip and the ala of the nose together—the one elevating the other depressing
them. When the cheeks are distended with air, and the aperture of the lips
narrowed, it is by the action of the buccinator that the forced expulsion of the
air is effected and regulated. The levator menti not only draws upwards the
integument of the chin, but it also protrudes the lower lip, as in pouting. The
muscles attached to the angles of the mouth are, along with others of the face,
intimately connected with the expression of the passions: those which pass
downwards not only raise the upper lip, but also push upwards the cheek, and
thus elevate the margin of the lower eyelid, as in mirth: and those which
descend from the angle of the mouth depress that part, as in grief. (On the
action of the facial muscles may be consulted, more especially, Sir Charles Bell,
‘Anatomy and Philosophy of Expression,” and Duchéne, ‘‘ Méchanisme de la
Physionomie Humaine,” Paris, 1862, and “ Physiol, des Mouvements,” &c., 1867.)

MUSCLES OF THE ORBIT. 275

MUSCLES OF TEE ORBIT.

Tn this sroup will be described seven muscles, namely, the elevator of
the upper eyelid before referred to, and six muscles of the eyeball, viz.,
the four straight and the two oblique muscles. Of these muscles, the
inferior oblique alone is confined to the fore part of the orbit ; all the
others take their origin at its back part, and pass longitudinally forwards
to their insertion in front.

The levator palpebree superioris is a slender muscle, which arises,
pointed and tendinous, above and in front of the margin of the optic
foramen, and, passing forwards over the eyeball, ends in a fibrous
expansion inserted into the anterior surface of the tarsal cartilage of
the upper eyelid.

Relations—Between this muscle and the roof of the orbit are situated the
fourth and frontal nerves and the supraorbital vessels, and beneath it are the
superior rectus muscle and the globe of the eye. In the lid, it is placed behind
the palpebral ligament, close to the membrana conjunctiva.

The four straight muscles of the eye surround at their origin the optic
nerve, and, passing forwards from that point, are inserted into the
front of the globe of the eye at four opposite equidistant parts, by
delicate expanded tendons which become blended into one at their
termination.

The superior rectus arises close in front of the foramen opticum,
and beneath the levator palpebree; the inferior rectus, internal
rectus, and external rectus are united in acommon tendinous attach-
ment around the circumference of the optic foramen, except above.
But the external rectus differs from the others in having two heads of
origin: the upper head unites with that of the superior rectus, the
second head arises from the common tendon and from a bony point on
the lower margin of the sphenoidal fissure close to its wider inner
end; and intermediate fibres proceed from a fibrous band between the
heads of origin. The four recti thus attached posteriorly, pass for-
wards, one above, one below, and one on each side of the eyeball,
becoming flattened as they he in contact with it, and are inserted by
short membranous tendons into the fore part of the sclerotic coat, at
an average distance of four lines from the margin of the cornea.

In length and breadth there are some differences among these muscles. The
external rectus exceeds the internal one in length. On the other hand, the
internal rectus is the broadest, and the superior the narrowest of all. Between
the heads of the external rectus is a narrow interval, which gives transmission to
the third and sixth nerves and the nasal branch of the fifth nerve, with the
ophthalmic vein.

The superior oblique or trochlearis is a narrow elongated muscle, —
placed at the upper and inner part of the orbit, internally to the levator
palpebre. It arises about a line in front of the inner part of the optic
foramen ; thence it proceeds towards the internal angle of the orbit,
and terminates in a round tendon which passes through a fibro-carti-
laginous ring or pulley (trochlea) attached to the fovea trochlearis of
the frontal bone; it is there reflected outwards and backwards, and
passes between the eye and the superior rectus to be inserted into the
sclerotic coat midway between the superior and external recti muscles,

nearly equidistant from the cornea and the entrance of the optic
2 2

276 MUSCLES OF THE HEAD AND NECK.

nerve. A synovial sheath lines the contiguous surfaces of the tendon
and pulley.

Relations.—This muscle is covered by the roof of the orbit, the fourth nerve
entering its upper surface ; and beneath it lie the nasal nerve and the internal
rectus muscle. ‘

Fig. 205.—A View or tHE Muscrzs

oF THE RicHt ORBIT, FROM THE

A OUTSIDE, THE OUTER WALL HAVING
BEEN REMOVED. (A. 7.) 4

B, Expianatory SkETcH OF THE SAME
Muscuzs.

a, supraorbital ridge ; 6, lower margin
of the orbit formed by the superior max-
illary bone ; ¢, anterior clinoid process ;
d, posterior part of the floor of the
orbit above the spheno-maxillary fossa ;
e, side of the body of the sphenoid
bone below the optic foramen and sphe-
noidal fissure; 7, sinus maxillaris ;
1, levator palpebre superioris, near its
insertion ; 2, pulley and tendon of the
superior oblique muscle; 8, tendon of
the superior rectus muscle at its inser-
tion upon the eyeball ; 4, in A, externa\
rectus ; 4’, in B, tendon of insertion of
the same muscle, a part of which has
been removed ; the double origin of the
muscle is shown at the apex of the orbit ;
5, the inferior oblique muscle crossing
the eyeball below the inferior rectus; 6,
the inferior rectus ; 7, in B, the inside of
the internal rectus, seen in consequence
of the removal of a part of the external
rectus, and near it, the end of the optic
nerve cut short close to the place of its
entrance into the eyeball.

—s
ANTS
J Uy YU ips

The inferior oblique is the only muscle of the eye which does not
take origin at the apex of the orbit. It arises from a minute de-
pression in the orbital plate of the superior maxillary bone, just within
the anterior margin of the orbit, and close to the external border of
the lachrymal groove. The muscle inclines outwards and backwards
between the inferior rectus and the floor of the orbit, and ends in a
tendinous expansion, which passes between the external rectus and
the eyeball, to be inserted on the external and posterior aspect of the
globe.

Varietics.—The levator palpebree sometimes gives offa slip from its inner
border, which passes to be inserted into the trochlea, forming the tensor trochlee
of Budge. A slip of a similar nature was described by Albinus as a case of
doubling of the levator palpebre, and by Mollinetti as a fifth rectus. The
levator palpebrze has been seen entirely wanting (Macalister).

The rectus externus may have its two heads separate to their insertion. thus
forming a double rectus (Albinus). Macalister has twice noted the absence of
the outer head.

The transversus orbiter (Bochdalek) consists of an arching slip of muscular
fibres passing from the anterior and superior portion of the os planum across
the upper surface of the eyeball to the outer wall of the orbit. It is probably,
as Macalister suggests, a displaced deep slip of the palpebral fibres of the orbi-
cularis palpebrarum,

MUSCLES OF THE ORBIT. 277

Nerves.—Five of the muscles of the orbit, viz., levator palpebre supe-
rioris, the superior, internal, and inferior recti and the inferior oblique, are
under the influence of the third pair or common oculo-motor nerve ; the external
rectus is supplied by the sixth pair, or abducent ocular, and the superior oblique
by the fourth pair, or trochlear nerve. From what is stated hereafter as to the
action of the muscles, it will appear that in all the consentaneous movements of
direction of the two eyes muscles are in action which receive their motor nerves
from two different sources.

Actions.—The levator palpebre superioris is, as its name implies, simply an
elevator of the upper eyelid, acting in this as the antagonist of the upper pal-
pebral part of the orbicularis muscle.

The eyeball is so situated in the structures which surround it in the orbit that
it is capable of free motion on a central fixed point: but it does not appear to
shift its place as a whole within the orbit, nor to undergo perceptible change of
form from the action of the muscles. The position of the point round which
the movements of the eyeball take place is nearly in the centre of curvature of the
posterior wall, and from half a line to a line behind the middle of the antero-
posterior axis of the eyeball.

The movements of the eyeball may be conveniently reduced to four kinds, viz.,
1, simple lateral movements in a horizontal plane; 2, simple movements of eleva-
tion or depression; 3, oblique movements of elevation or depression, and 4,
movements of rotation. In the first two kinds the vertical meridian of the eye
is not subject to any change of inclination ; in the third kind the movements of
direction are accompanied by a small amount of rotation or inclination of the
vertical meridian to one or other side; and in the fourth kind, when simple, the
whole movement is one of inclination of the vertical meridian. These movements
however, unless perhaps the first, are seldom simple, but more frequently different
kinds are combined together. The three first kinds constitute the various move-
ments of direction by which the visual axis is turned within certain limits to
various points in space; the extent of motion being about 90° in the vertical and
100° in the horizontal direction. Simple movements of rotation do not appear to
occur to any considerable extent, and it has been ascertained by experiment that
they do not, as was supposed by Hueck and others, maintain the eyeballs in a
fixed position during inclined movements of the head

In these different movements the six muscles of the eyeball may aavan-
tageously be considered as acting in three pairs. 1st. In the horizontal move-
ments the internal and external recti muscles are the sole agents, the one acting
as an adductor and the other as an abductor; and this movement they effect
without any rotation, their line of action being exactly in the horizontal plane
of the eyeball. 2nd. It is different with the superior and inferior recti; for while
these muscles undoubtedly are respectively the most direct elevators and de-
pressors of the cornea, they have both a tendency, from the line of their action
being to the inside of the centre of motion of the eyeball, to produce inward
direction with a small amount of rotation. This tendency is corrected by the
association of the oblique muscles in all upward and downward movements ; the
inferior oblique being associated with the superior, and the superior oblique
with the inferior rectus muscle. The simple action of the superior oblique
muscle, when the eye is directed straight forward, is to produce a movement of
the cornea downwards and outwards, that of the inferior oblique to direct the
comea upwards and outwards, and in both with a certain amount of rotation,
though in different directions in the two cases. But these movements caused
by the oblique muscles are precisely those which are required to neutralise the
inward direction and rotatory movements produced by the superior or the
inferior rectus, and accordingly, by the combined action of the superior rectus
and the inferior oblique muscles a straight upward moyement is effected, while
a similar effect in the downward direction results from the combined action of
the inferior rectus and superior oblique muscles.

It has been further shown that in all the oblique movements of direction a
combination takes place of the action of the oblique with that of the recti
muscles. Here, however, two recti muscles are in action and are associated with
one oblique muscle; as, for example, in the upward and inward direction, the

278 MUSCLES OF THE HEAD AND NECK.

superior and internal recti with the inferior oblique; and in the downward and
inward direction the inferior and internal recti with the superior oblique. And
the same is true of the upward and outward and downward and outward move-
ments of direction ; for in all these movements the action of the oblique muscles
is necessary to control or supplement the rotatory tendency of the recti muscles ;
and in the consentaneous movements of the two eyes the whole six muscles
must co-operate in both eyes to produce that perfect agreement in their move-
ments of direction and convergence which is required for perfect vision.

It is unnecessary here to enter into the detail of the modifications of these
actions of the muscles which must accompany changes in the various consenta-
neous movements of the eyes, as, for example, in the convergence which is asso-
ciated with the adjustment of the eyes to near and distant vision. (Consult
G. Johnston in article “ Orbit,’ of Cycloped. of Anat. and Physiol., Jacob in
Dublin Med. Press, 1841; John S. Wells, in the Ophthalmic Hosp. Reports,
vol. ii. 1859-60; Von Graefe, in Archiv fiir Ophthalmologie, vol. i. p. 1; and
other works of that author, and of Alfred Graefe, and other Ophthalmologists,
especially those on Strabismus. Also Helmholtz in his Physiological Optics.)

Fasciz of the Orbit.—The space within the orbit which is not occupied by
the eyeball and its muscles, or other parts belonging to it, is completely filled
with soft fat and delicate yielding connective tissue. In various places this last
is condensed into layers of slender fascie of various degrees of strength. One
layer of this structure forming the capsule of Tenon, surrounds the eyeball on
every side except in front, where it is reflected on the inside of the conjunctiva
and eyelids, and this layer is so loosely connected with the surrounding parts
that it seems to serve all the purposes of a synovial membrane in the ball and
socket-like disposition of the globe of the eye in its padding. The various
muscles pierce this capsule at a short distance from the place of their insertion
into the sclerotic. From the capsule of Tenon, sepia of fascial connective tissue
spread outwards mainly in the direction of the recti muscles, all of which
receive delicate investments from the structure ; a layer also spreads between
the muscles and the periosteal lining of the orbit. In two places these septa of
fascia are of greater strength than elsewhere, viz.,on the inside towards the
lachrymal sac and eyelids, and on the outside towards the margin of the orbit, where
it is united with the external ligament of the palpebre and the periosteum.

In several parts of these fascial structures, more especially in those last men-
tioned, plain or unstriped muscular fibres have been detected, and these, together
with the elastic connective tissue are conceived to act in restoring the position of
parts after the action of the voluntary muscles is over. These involuntary
muscles are under the influence of the cervical sympathetic nerves. (See Henle’s
Anatomie d. Mensch., vol. ii., and Merckel in the Handbuch der Gesammt. Augen-
heilkunde, Ist part, 1874; H. Miiller, Sitzungsb. d. Wiirtzburg. Gesellsch. 1858,
and Turner, Nat. Hist. Rev., 1862 ; Cruveilhier, Traité d’Anatomie, &c.)

MUSCLES OF -MASTICATION.

The masseter, temporal, and two pterygoid muscles form‘a group of
muscles of mastication, which may be properly considered together.

The masseteric fascia is a continuation upwards of the deep fascia
of the neck over the masseter muscle. It is firmly bound down to the
outer surface of the muscle, and is attached superiorly to the zygoma.
Posteriorly it closely invests the parotid gland (fascia parotidea) ; it
likewise sends upwards a process on the posterior and deep surfaces
of the parotid gland; and a strong band of this process, the s/y/o-
maxillary ligament, extending from the angle of the jaw to the styloid
process, separates the parotid and submaxillary glands.

The masseter is a thick quadrate muscle, whose fibres form two
portions differing in size and direction. The swperficial part, obliquely
foursided in form, arises from the lower border of the malar bone in
the anterior two-thirds of the zygomatic arch, chiefly by thick tendons

MUSCLES OF MASTICATION. 279

projecting down between the muscular fasciculi, to which they afford an
extensive surface of origin: its fibres proceed downwards and a little
backwards to be inserted into the lower half of the ramus of the jaw,
extending as far as the angle. The deep part of the muscle, of a tri-
angular form, consists of fibres which are much shorter than those of
the superficial part, and are directed downwards and forwards. They
arise from the posterior third of the lower border and from all the deep
surface of the zygomatic arch, and, becoming united with the superficial
part, are inserted into the upper half of the ramus of the jaw, includ-
ing the coronoid process: only the upper and back part of this portion
of the muscle is left uncovered by the superficial portion.

Iclations.—The external surface of the masseter muscle is covered for the most
part only by the skin and fascia ; it is, however, overlapped behind by the parotid
gland, and crossed by its duct; the branches of the facial nerve and the trans-
verse facial artery also rest upon it. Its inner surface is towards the buccinator,
from which it is separated by soft adipose tissue ; it is in close contact with the
ramus of the jaw, and covers a nerve and vessels which enter it over the sigmoid
notch of that bone.

The temporal fascia is a dense white shining aponeurotic structure,
which covers the temporal muscle above the zygoma, and gives attach-
ment to some of its fibres of origin. It is attached superiorly to the
posterior border of the malar bone and to the temporal ridge on the
frontal, parietal, and temporal bones; while inferiorly, where it is sepa-
rated by a quantity of fat into two layers, it is attached to the zygoma,
the superficial layer to the outer surface, and the deep layer to the inner
surface of that process. ‘This dense fascia is separated from the integu-
ments by the layer of thin membrane descending from the epicranial
aponeurosis, and by the auricular muscles; and from the temporal
muscle below, by a layer of fat.

The temporai muscle is fan-shaped, and arises from the whole
surface of the temporal fossa, with the exception of the anterior or
malar wall, and from the deep surface of the temporal fascia, as it
passes down over it to the zygoma ; some of its posterior fibres arising
from this fascia blend with the deep fibres of the masseter muscle.
The direction of the anterior fibres is nearly vertical, that of the middle
fibres oblique, and that of the posterior fibres at first horizontal. The
fibres converge as they descend, and all terminate in a tendon, which,
emerging from the interior of the muscle, is implanted into the inner
surface and anterior border of the coronoid process of the lower jaw-
bone, as far down as the union of the body and ramus of the jaw.

Lelations.—The upper part of the muscle is closely covered by the temporal
fascia ; the lower and anterior part is imbedded in fat continuous with that
which lies between the masseter and buccinator muscles; the insertion of the
tendon is mainly concealed by the lower jaw. Between the muscle and the bone
ot the temporal fossa are the deep temporal arteries and nerves, which penetrate
its substance. In contact with the deep surface of the muscle near its insertion
the buccal nerve descends, and at the posterior border of the insertion the
masseteric nerve and artery emerge,

The internal pterygoid muscie arises from the pterygoid fossa ; its
fibres, tendinous and fleshy, being attached mostly to the inner surface
of the external pterygoid plate, and that portion of the tuberosity of
the palate-bone which is situated between the pterygoid plates. Thence
it is inclined downwards, with a direction backwards and outwards, and

280 MUSCLES OF THE HEAD AND NECK.

is inserted into the angle and the inner surface of the ramus of the jaw
as high as the dental foramen.

Relations.—-The internal pterygoid muscle is placed on the inner side of the
ramus of the jaw, somewhat in the same manner as the masseter lies on the
outside. Between the external surface of the muscle and the ramus of the
maxilla are the internal lateral ligament and the internal maxillary vessels, with
the dental artery and nerve; and at its upper part the muscle is crossed by the
external pterygoid muscle. Its inner surface is in contact, whilst in the ptery-
goid groove, with the tensor palati muscle, and lower down with the superior
constrictor of the pharynx.

206.

Fig. 206.—Views or THE Prerycorp Musctes—A, rRoM THE OUTER SIDE; B, FROM

THE INNER sIpE. 4}

1, external pterygoid ; 2, internal pterygoid—the outer surface in A, the inner surface
in B

The external pterygoid muscle, occupying the zygomatic fossa,
arises by two. fleshy heads placed close together, the superior of which
is attached to that part of the external surface of the great wing of the
sphenoid bone which looks into the zygomatic fossa, and to the ridge
which separates that surface from the temporal fossa; while the in-
ferior, which is larger, is attached to the outer surface of the external
pterygoid plate, and to the tuberosities of the palate and upper max-
illary bones. ‘The fibres from both heads pass backwards, and converge
to be inserted into the fore part of the neck of the condyle of the lower
jaw, and into the interarticular fibro-cvartilage of the temporo-maxillary
articulation.

Relations.—The internal maxillary artery is usually placed on the outer surface
of this muscle, passing thence between the heads of origin; while the buccal
nerve issues from between those heads. The deep surface rests against the
upper part of the internal pterygoid muscle, whose direction it crosses, also the
internal lateral ligament of the lower jaw, the inferior maxillary nerve, and the
middle meningeal artery. The upper border is in contact with the great wing of
the sphenoid bone, and is crossed by the deep temporal nerve and arteries.

Varieties —The pterygoidcus proprius (Henle). This is nearly a vertical slip,
which passes from the crest of the great wing of the sphenoid to the tuberosity
of the palate bone or to the posterior margin of the exvernal pterygoid plate. In
some cases reported by Mr. Wagstaffe (Journ. of Anat. vol. v., p. 281), in which
this slip was present, the maxillary head of the external pterygoid was absent,
and some of the ordinary fibres arose from those vertical bands, Another form

SUPRA-HYOID MUSCLES. 281

of this muscle has been described by Macalister, as passing superficial to the
external pterygoid to be inserted into the tuberosity of the maxillary bone.

Fig. 207.—View oF THE LOWER PART Fig. 207.
oF THE SKULL AND Facz, FROM BE-
HIND, TO SHOW THE ATTACHMENTS OF
THE PrERYGOID AND SOME OTHER
Musctrs (modified from Bourgery).
(ACU)

a, placed above the basi-sphenoid
bone, below which are seen the posterior
nares and palate; 0, transverse section
through the temporal bone ; ¢, roof of
the mouth ; d, back of the head and
neck of the lower jaw, above which are
seen the synovial cavities of the joint
divided by the interarticular fibro-
cartilage ; e, placed below the symphysis
menti; 1, on the left internal pterygoid
muscle; 1’, on the right side, the lower
part of the same muscle, of which the
middle portion has been removed to
show the external pterygoid; 2, the
lower thick portion of the external pterygoid ; 2’, on the right side points to the upper
smaller portion of the muscle, attached in part to the interarticular plate ; 3, small
portions of the genio-hyoid and genio-hyo-glossus muscles cut short at their attachment
to the genial tubercles ; 4, the attachment of the mylo-hyoid muscle cut short; 5, the
attachment at the side of the symphysis of the anterior .belly of the digastric muscle ;
6, the masseter muscle descending to the angle of the jaw.

Nerves.—The four muscles above described receive their motor nerves
from one source, viz., the external muscular branches of the fifth pair, which
may be traced to the lesser or motor root of that nerve. These nerves are named
from the muscles they respectively supply. There are usually two branches to
the temporal, and one to each of the other muscles.

Actions.—The masseter, temporal, and internal pterygoid muscles are elevators
of the lower jaw, and generally act in concert, bringing the lower teeth forcibly
into contact with the upper. The opposite movement of depressing the jaw, not
being opposed by any resisting obstacle, requires less force, and is effected by
muscles of much smaller size, the principal of which is the digastric muscle
hereafter described. The external pterygoid muscle, having the great body of its
fibres nearly horizontal, draws forwards the condyle of the jaw, and, when the
muscles of both sides act together, the lower jaw is protracted so as to make the
lower incisor teeth project beyond the upper; but their more usual mode
of action is alternately on the two sides, as in tke grinding movement of
the molar teeth, in which the horizontal movements of the external pterygoids
are associated with the elevating actions of the other muscles. The masseter
and internal pterygoid muscles assist in protracting the jaw ; the temporal alone
is a retractor. The two pterygoid muscles of one side, in advancing one condyle
of the jaw, necessarily throw the teeth towards the opposite side.

MUSCLES BETWEEN THE LOWER JAW AND THE HYOID BONE.

The digastric muscle, extending from the temporal bone to the
lower jaw, consists of two elongated muscular bellies united by an
intervening rounded tendon. The posterior belly, longer than the
anterior, arises from the digastric groove of the temporal bone, and is
directed downwards, forwards, and inwards: the anterior is attached
to arough depression situated on the lower border of the lower jaw,
close to the symphysis menti; it is less tapering than the posterior
belly, and is directed downwards and backwards, The intervening

282 MUSCLES OF THE HEAD AND NECK.

tendon is connected with the body and great cornu of the os hyoides by
a broad band of aponeurotic fibres in the form of a loop, and lined with
synovial membrane, and by the fleshy fibres of the stylo-hyoid muscle,
through which the tendon passes.

Relations —The anterior belly, placed immediately beneath the deep cervical
fascia, rests on the mylo-hyoid muscle; it is connected with its fellow of the
opposite side by dense fascia, and occasionally is united by muscular fibres to it
or to the mylo-hyoid muscle.

The posterior belly is covered by the mastoid process and the muscles arising
from that bone, and crosses the external carotid artery, and the internal jugular
vein,

Fig. 208. Fig. 208.—Virw or THE Sus-
MAXILLARY MuscLEs AND
tHE DEPRESSORS OF THE
Hyor Bonr anp Larynx,
FROM BEFORE. (A. T.) 3

On the right side, the platys-
ma alone has been removed ;
on the left side both the
bellies of the digastric, the
stylo-hyoid, the mylo-hyoid,
the sterno-hyoid, and omo-
hyoid muscles have been re-
moved : a, symphysis; 0,
angle of the lower jaw; ¢,
middle of the body of the
hyoid bone; d, mastoid pro-
cess ; €, placed on the front of
the thyroid cartilage, points
to the thyro-hyoid muscle ; f,
upper part of the sternum ;
g, lateral lobe, and +, isth-
mus of the thyroid gland ;
above +, the front of the
cricoid cartilage covered by
the crico-thyroid muscle ; 1,
posterior belly ; 1’, anterior
belly of right digastricmuscle;
2, right mylo-hyoid ; 3, left
genio-hyoid ; 4, hyo-glossus ;
5, stylo-glossus ; 5’, a portion
of it seen on the right side ; 6, stylo-hyoid of the right side ; 7, stylo-pharyngeus of the
left side ; 8, placed on the levator scapule, points to the left middle constrictor of the
pharynx ; 9, placed on the middle scalenus, points to the left inferior constrictor ; 10,
right sterno-hyoid ; 11, placed on the left sterno-thyroid, points also to the lower part of
the right muscle ; 12, placed on the right sterno-mastoid, points to the upper and lower
bellies of the right omo-hyoid.

Varieties.—The digastric muscle is subject to raany variations. The posterior
belly may receive an accessory slip from the styloid process (Wood), or from
the angle of the lower jaw (Henle). It has been seen arising from the styloid
process. Rarely the muscle is monogastric, the posterior belly alone being present
and being inserted into the ramus of the jaw (McWhinnie). The anterior belly
is frequently divided into two or more parts, one or even two of which may cross
the middle line and decussate with similar slips from the muscle of the opposite
side ; or a slip sometimes passes to the median raphé of the mylo-hyoid, with
which and its fellow of the opposite side it becomes incorporated. The tendon
of the digastric has been seen in front of, or more rarely behind the stylo-hyoid
instead of passing through it.

The mento-hyoid (Macalister) is an occasional mesial slip found passing

SUPRA-HYOID MUSCLES. 283

from the body of the os hyoides to the chin. It sometimes consists of two
parallel bands, and Macalister suggests that it may be a differentiated portion of
the platysma.

The stylo-hyoid muscle lies close to the posterior belly of the
digastric muscle, being a little behind and beneath it. It arises from
the outside of the middle of the styloid process of the temporal bone,
and inclines downwards and forwards, to be inserted into the os hyoides
at the union of the great cornu with the body. Its fibres are usually
divided into two fasciculi near its insertion, for the transmission of the
tendon of the digastric muscle.

Relations—The upper part of the stylo-hyoid muscle lies deeply, being covered
by the sterno-mastoid and digastric muscles, and by part of the parotid gland ;
the middle crosses the external carotid artery ; the insertion is comparatively
superficial.

Varieties—This muscle is sometimes wanting ; occasionally a second is present
(stylo-hyoideus alter,— Alb.) The position too may be varied—it has been found to
the inner side of the external carotid artery instead of over that vessel. (‘‘ The
Anatomy and Operative Surgery of the Arteries,’ by R. Quain, plate 12, fig. 5.
Macalister, Journal of Anat., vol. v., p. 28.)

The mylo-hyoid muscle arises from the mylo-hyoid ridge along the
inner surface of the lower jaw, extending from the last molar tooth to
the symphysis. The posterior fibres are inserted into the body of the

Fig. 209.—A, tue Lowsr Jaw anp Hyorp
Bone, FROM BELOW, WITH THE My1o-Hyorp
Muschis ATTACHED.

B, THE SAME FROM BEHIND, WITH THE Mvto-
Hyorp ayp Gunro-Hyom Muschis ATTACHED,
(ARTS ea

a, the symphysis ; 6, the angle of the lower
jaw ; c, the lower border of the body of the
hyoid bone ; d, in B, the inferior dental fora-
men and upper end of the mylo-hyoid ridge ;
1, 1’, the mylo-hyoid muscles; 2, 2’, the
genio-hyoid muscles from above ; 3, the cut
ends of the attachment of the genio-glossi
muscles to the superior genial spines.

os hyoides; the rest, proceeding
parallel to the fibres behind, and
becoming gradually shorter, join at
an angle with those of the corres-
ponding muscle, forming with them
a sort of raphé along the middle
line, from the symphysis of the jaw
to the os hyoides. Thus the two
muscles together form a floor below the anterior part of the mouth
(diaphragna oris of Meyer).

Relations.—The lower surface of the mylo-hyoid muscle is covered by the
digastric muscle, the submaxillary gland, and the submental vessels and nerve.
The deep surface which looks upwards and inwards, is in contact with the genio-
hyoideus and part of the hyo-glossus and stylo-glossus muscles, the ninth and
gustatory nerves, the sublingual gland, and the duct of the submaxillary gland.
The posterior border alone is free and unattached, and behind it the duct of the
submaxillary gland turns, in passing to the mouth,

p cc iQ e
¢

284 MUSCLES OF THE HEAD AND NECK.

Varieties —This muscle may be inseparably united with, and even upon ‘one
side replaced by the anterior belly of the digastric. It frequently receives an
accessory slip from one of the other hyoid muscles, as the sterno-hyoid, omo-
hyoid, or stylo-hyoid.

The genio-hyoid is a narrow muscle arising from the inferior of the
two genial tubercles behind the symphysis of the jaw, and inserted into
the anterior surface of the body of the hyoid bone.

Relations.—It is in contact above with the lower border of the genio-glossus
muscle, and below with the mylo-hyoid and with its fellow in the middle line.

Nerves.—The muscles of this group receive their motor nerves from various
sources, viz., the anterior belly of the digastric and the mylo-hyoid from
the mylo-hyoid branch of the inferior maxillary division of the fifth nerve, and
the posterior belly of the digastric and the stylo-hyoid from the facial nerve neat
the place of its exit from the stylo-mastoid foramen. ‘The genio-hyoid receives
its motor nerve from the hypoglossal. 5

Actions.—The genio-hyoid and mylo-hyoid muscles draw the hyoid bone
upwards and forwards, as happens in the first stage of deglutition. The stylo-
hyoid muscles draw it upwards and backwards, and come into action in raising
the pitch of the voice. The anterior belly of the digastric muscle acts by itself
like the genio-hyoid and the posterior half like the stylo-hyoid ; but when both
bellies act together they are
capable of producing two
movements, in one of which,
when the lower jaw is fixed,
the hyoid bone is elevated,
and in the other, when the
hyoid bone isheld downwards
by the depressing muscles,
the lower jaw is depressed.

Fig. 210.—Muscizs oF THE
Toneur, PHarynx, &c., oF
THE LEFT sipE. (A. T.) 3
a, external pterygoid pro-

cess; 0, styloid process; ¢,

section of the symphysis of the
lower jaw; d, front of the

body of the hyoid bone; e,

thyroid cartilage ; f, cricoid

cartilage ; between d and e,

the thyro-hyoid membrane and

ligament ; g, isthmus of the
thyroid gland ; 1, stylo-glossus

muscle ; 2, stylo-hyoid ; 3,

stylo-pharyngeus ; 4, cut edge

of the mylo-hyoid ; 5, genio-

hyoid ; 6, genio-hyo-glossus ; 7,

hyo-glossus ; 8, lingualis in-

ferior ; 9, part of the superior

constrictor of the pharynx ; 10,

back part of the middle con-

strictor ; 11, inferior constrictor;

12, upper part of the cesopha-

gus ; 13, crico-thyroid muscle.

MUSCLES OF THE TONGUE.

The tongue is a muscular organ attached posteriorly to the hyoid
bone, and inferiorly to the lower jaw. It is composed partly of fibres

MUSCLES OF THE TONGUE, 285

peculiar to itself—the ifrinsic muscles, which will be noticed along
with the tongue; and partly of muscles arising from neighbouring
parts—the eztrinsic muscles about to be described.

The genio-glossus or genio-hyo-glossus muscle is fan-shaped, and
is placed vertically in contact with its fellow in the mesial plane. It
arises by a short tendon from the superior genial tubercle behind the
symphysis of the jaw: from this its fibres diverge, to be inserted, the
inferior, for the most part, into the body of the hyoid bone, and a
few into the side of the pharynx; the superior imto the tip of the
tongue ; and the intermediate fibres into the whole length of the
tongue spreading outwards in its substance.

Relations —The external surface is in contact with the lingualis inferior, hyo-
glossus and stylo-glossus muscles, the sublingual gland, the ranine vessels, and
the nerves of the tongue, and its lower border with the genio-hyoid muscle.

Varieties—Occasional slips of this muscle have been noticed passing to the
epiglottis (Luschka), or to the pharynx (Winslow), or to the stylo-hyoid ligament
(Sémmerring). It has also been found united anteriorly with the genio-hyoid
muscle.

The hyo-glossus is a flat quadrate muscle, arising from the whole
length of the great cornu, from the lateral part of the body, and from

Fig. 211.—Drre Muscies or THE
CurEK, PHarynx, &c. (modified
from Cloquet). (A. 1.) 4

The pharynx has been distended
by stufiing. «a, external pterygoid
process ; 6, styloid process, with
short portions of the three styloid
muscles attached ; c, body of the
lower jaw, which has been divided
at the place where the pterygo-
maxillary ligament + is attached ;
d, body of the hyoid bone; e,
thyroid cartilage ; 7, ericoid carti-
lage ; g, trachea ; 1, outer part of
the orbicularis oris muscle ; 2, buc-
cinator ; 3, superior constrictor of
the pharynx ; 4, middle constrictor ;
5, inferior constrictor; 6, ceso-
phagus ; 7, points by three lines to
the lower parts of the stylo-glossus,
stylo-hyoid, and stylo-pharyngeus
muscles respectively ; 8, maylo-
hyoid ; 9, hyo-glossus, of which a
small part is removed posteriorly to
show the attachment of the middle
constrictor ; 10, thyro-hyoid.

the small cornu of the hyoid
bone ; it passes upwards to be
inserted into the side of the
tongue, blending with the
stylo-glossus and palato-
glossus muscles.

Relations.—The hyo-glossus is concealed by the digastric, stylo-hyoid and
mylo-hyoid muscles, except at its posterior inferior angle: the deep part of the
submaxillary gland rests on its surface, and it is crossed from below upwards by

286 MUSCLES OF THE HEAD AND NECK.

the hypoglossal nerve, the Whartonian duct, and the gustatory nerve. It covers
the genio-glossus and the origin of the middle constrictor of the pharynx,
together with the lingual artery and glosso-pharyngeal nerve.

Varicty.—Triticeo-glossus (Bochdalek), This is a small muscle which arises
from the cartilago triticea in the posterior thyro-hyoid ligament, and passes
upwards and forwards to enter the tongue along with the posterior part of
the hyo-glossus. It always lies behind the lingual artery.

The stylo-glossus, the shortest of the three muscles which spring
from the styloid process, arises from that process not far from its point,
and from the stylo-maxillary ligament, to which in some cases the
greater number of its fibres are attached by a thin aponeurosis : pass-
ing forwards and slightly downwards, it is inserted along the side and
under part of the tongue as far as the tip, its fibres decussating, and
becoming blended with those of the hyo-glossus and palato-glossus
muscles.

Relations.—This muscle lies deeply beneath the parotid gland, and is crossed
by the gustatory nerve.

Varieties —The mylo-glossus (Wood) is a small accessory slip, which usually
comes from the angle of the lower jaw, but has also been seen coming from the
stylo-maxillary ligament. Occasionally the whole muscle arises from one of
these points. A very rare origin has been noted by Gruber from the external
meatus. Albinus and Béhmer have noted entire absence of the muscle, and
various anatomists have seen it double.

Nerves.—The muscles of this group are all supplied with branches from
the hypoglossal or motor linguz nerve.

Actions.—The genio-glossus muscle has a complicated action, one part pro-
truding and another retracting the tongue, while a third depresses the middle
portion of the organ. Protrusion is effected by contraction of its posterior, and
retraction by contraction of its anterior fibres, while the middle part, or nearly the
whole muscle, acts as a depressor. In deglutition the stylo-glossus muscle raises
the side of the tongue spasmodically backwards and upwards, while the hyo-
glossus opposes that action. In other circumstances the first muscle assists In
forming a hollow, and the second a convexity on the dorsum of the tongue.

MUSCLES OF THE PHARYNX AND SOFT PALATE.

THE PHARYNX, the dilated upper part of the alimentary tube,
extending from the base of the skull to the cesophagus, presents at the
sides and back a continuous wall, in great part formed and supported
by distinct muscles resting posteriorly on the vertebral column, and is
open in front towards the nasal cavity, the mouth, and the larynx.

The CONSTRICTORS OF THE PHARYNX are three thin expanded
muscles which invest the pharyngeal wall, overlapping one another
from below upwards, so that the lowest is most superficial.

The inferior constrictor muscle arises from the side of the cricoid
cartilage, and from the oblique lateral ridge and upper and lower borders
of the thyroid cartilage, and curves backwards, expanding as it proceeds,
and unites with its fellow in the middle line behind the pharynx. The
direction of the inferior fibres is horizontal, concealing and over-
lapping the commencement of the cesophagus; the rest ascend with

increasing degrees of obliquity, and cover the lower part of the middle
constrictor.

Relations—This muscle lies in contact posteriorly with the cervical vertebree
and the longus colli muscle ; its outer surface is related to the side of the larynx,

MUSCLES OF THE PHARYNX. 287

the thyroid body, the carotid artery, and the sterno-thyroid muscle; and
from this last, where the two muscles meet on the thyroid cartilage, some fibres
are continued into the constrictor. By its inner surface it is related to the
middle constrictor, the stylo-pharyngeus, the palato-pharyngeus, and the mucous
membrane of the pharynx. The two laryngeal nerves pass inwards to the larynx,
close respectively to the upper and lower margins of this constrictor—the upper
being interposed between it and the middle constrictor, the lower between it and
the cesophagus.

Fig. 212.—Virw oF Fig. 212.
THE Muscius OF
THE PHarynx, &c.,
FROM BEHIND (after
Bourgery). 4

The back part of
the skull, the ver-
tebral column and
back parts of the
ribs are removed. «,
cut surface of the
basilar process ; 8,
the clavicle; c, the
first + rib > d, the
ramus of the lower
jaw; ¢, posterior ex-
tremity of the great
cornu of the hyoid
bone; jf, posterior
surface of the manu-
brium of the ster-
num ; 1, superior
constrictor muscle of
the pharynx; above
it the fibrous mem-
brane which closes
the pharynx ; 2, mid-
dle constrictor ; 2’,
a dotted line, indi-
cating the direction
of the lower part of
the muscle ; 3, the
inferior constrictor ;
4, cesophagus ; 5, in-
ternal pterygoid ; 6,
stylo-glossus ; 7, pos-
terior belly of the
digastric ; 8, a portion of the stylo-hyoid surrounding the tendon of the digastric ; 9,
sterno-mastoid ; 10, upper belly of the omo-hyoid ; 11,sterno-thyroid muscle (represented
somewhat too broad).

The middle constrictor muscle arises from the upper surface of the
cornua of the os hyoides, and from the stylo-hyoid ligament : its fibres,
diverging greatly, pass back to the middle line of the pharynx behind,
the lowest fibres inclining downwards, beneath the inferior constrictor,
the highest ascending and overlapping the superior constrictor, and
the intermediate fibres running transversely.

Relations.—This muscle is separated from the superior constrictor by the stylo-
pharyngeus muscle and the glosso-pharyngeal nerve, while between its origin
and that of the inferior constrictor the superior laryngeal nerve pierces the thyro-
hyoid membrane.

Varieties Fibres of the middle constrictor have been observed to arise from
the body of the os hyoides and the thyro-hyoid ligament, (syndesmo-pharyngeus

288 MUSCLES OF THE HEAD AND NECK.

of Douglas), and a slip is frequently continued into it from the genio-hyo-
glossus muscle. The two middle constrictors have been found connected behind
to the base of the skull by muscular fibres or by a fibrous band (Albinus).

The superior constrictor arises by fibres attached in series from
below upwards, to the side of the tongue, to the mucous membrane of
the mouth, to the extremity of the mylo-hyoid ridge of the jaw, to the
pterygo-maxillary ligament, and to the lower third of the posterior
border of the internal pterygoid plate. ‘The fibres curve backwards,
and are mostly blended with those of the corresponding muscle along
the middle line, a few ending posteriorly in the aponeurosis which fixes
the pharynx to the base of the skull. The upper margin curves round
the levator palati and the Eustachian tube ; and the space intervening
between this concave margin of the constrictor and the base of the skull
is closed by fibrous membrane.

Relations.—In contact with the outer surface of this muscle are the internal
carotid artery, the eighth and other large nerves, the middle constrictor, which
overlaps a considerable portion, and the stylo-pharyngeus, which descends to
the pharynx between the two constrictors. It conceals the palato-pharyngeus
and the tonsil, and is med by mucous membrane. It is united to the buccinator
muscle anteriorly by the pterygo-maxillary ligament.

Variety —The azygos pharyngis (Meckel) is a small mesial slip about half an
inch in length, lying behind the upper and middle constrictors, It arises from
the pharyngeal spine on the under surface of the basilar process of the occipital
bone, and is inserted into the median raphé of the pharynx.

The stylo-pharyngeus, larger and longer than the other styloid
muscles, arises from the inner surface of the styloid process, near the
root, and proceeding downwards and inwards to the side of the pharynx,
passes under cover of the middle constrictor muscle, where it detaches
some fibres to the constrictors, and, gradually expanding, is connected
with the palato-pharyngeus muscle, and ends in the superior and post-
erior borders of the thyroid cartilage.

Relations —The external surface of this muscle is, in the upper part of its
extent, in contact with the styloid process, the stylo-hyoideus muscle, and the
external carotid artery ; in the lower, with the middle consirictor of the pharynx.
Internally it rests on the internal carotid artery and jugular vein ; and lower
down on the mucous membrane of the pharynx. The glosso-pharyngeal nerve
is close to the muscle, and crosses over it in turning forwards to the tongue.

Varieties—The cephalo-pharyngeus (Sandifort) is a small occasional muscle
which usually arises from the vaginal process of the temporal bone, but some-
times also from the spine of the sphenoid or from the angle of the petrous bone
(Macalister) ; in its course it is separated from the stylo-pharyngeus by the
glosso-pharyngeal nerve, and it is finally lost below the inferior constrictor of the
pharynx.

The salpingo-pharyngeus (Santorini), arising by a tendon from the Eustachian
tube, descends in the interior of the pharynx towards its back part, and, after
joining with the palato-pharyngeus, is lost in the muscular structure of the
cavity.

THE Sorr PALATE (velum pendulum palati) is a movable curtain,
continued backwards from the hard palate. It presents posteriorly a
free pendulous margin, prolonged in the middle into a conical process,
the wvula, and at each side into two prominent curved folds, the ante-
rior of which, the anterior pillar of the fauces, descends to the side of
the tongue, while the posterior fold, the posterior pillar of the fauces,
runs downwards and backwards into the pharynx; between the two is

MUSCLES OF THE PALATE. 289

lodged the tonsil. The constricted passage between the anterior pillars,
leading from the mouth to the pharynx, is called the zshmus of the

Fig. 213.—Dracrammatic VIEW OF THE
Musciis OF THE PHARyNX, &C,, FROM
BEHIND. (A. 1.) 3

The posterior wall of the pharynx has
been divided by a vertical incision in
the middle line, and the cut edges drawn
to the side so as to expose the nasal,
buccal, and laryngeal openings ; @, is
above the cut surface of the basi-occipital
bone, and below that are the posterior
nares ; 0, cartilage of the left Eustachian
tube ; c, back of the ramus of the lower
jaw ; d, posterior border of the thyroid
cartilage ; e, upper part of the cricoid
cartilage ; f, base of the tongue above
the epiglottis; g, lower end of the
pharynx leading into the gullet ; 1, supe-
rior constrictor of the pharynx seen from
within, and part of the middle con-
strictor ; 2, palato-pharyngeus ; 2’, the
lower part of the same muscle, on the
right side; 3, placed on the internal
pterygoid muscle, points to the levator
palati; 4, the right circumflexus palati
muscle winding round the hamular
process; 5, the azygos uvulx ; ahove
e, the transverse arytenoid, and below
it on each side the posterior crico-
arytenoid muscle,

fauces. The soft palate is acted on by five pairs of elongated muscles,
two superior, one intermediate, and two inferior.

The palato-glossus muscle, or constrictor isthmi faucium,
occupies the anterior pillar of the fauces. Superiorly it is anterior to
all the other muscles of the velum, and its fibres are continuous with
those of its fellow of the opposite side; inferiorly, it is lost on the
side of the tongue. ;

The palato-pharyngets muscle, occupying the posterior pillar of
the pharynx, arises in the soft palate by fibres connected with those of
the opposite side, and passing partly above and partly below the levator
palati and azygos muscles. As the muscle descends it becomes greatly
expanded, and its fibres are found extended from the posterior cornu
of the thyroid cartilage, back to the middle line of the pharynx
posteriorly.

The azygos uvule muscle (Morgagni), so called from having been
supposed to be a single muscle, consists of two slips, which arise, one
on each side of the middle line, from the tendinous structure of the
soft palate, and, sometimes, from the spine of the palate plate, and
descend into the uvula. The two slips are separated by a slight
interval above, and unite as they descend.

The levator palati muscle arises from the extremity of the petrous
portion of the temporal bone, in front of the orifice of the carotid
canal, and from the cartilaginous part of the Eustachian tube. Ap-
proaching the middle line as it passes downwards and forwards, it is

inserted aponeurotically into the posterior part of the soft palate, and
VOL, I. U

290 MUSCLES OF THE HEAD AND NECK.

meets its neighbour of the opposite side. In its upper part it is
piaced above the concave margin of the superior constrictor.

The circumflexus or tensor palati arises from the navicular fossa
at the root of the internal pterygoid plate, from the outer side of the
Eustachian tube, from the spine of the sphenoid, and the edge of the
tympanic plate of the temporal bone. It descends perpendicularly,
resting on the internal pterygoid plate, between it and the internal
pterygoid muscle, and ends in a tendon which, turning round the
hamular process, where a synovial burse smooths its passage, extends
horizontally inwards, and terminates in the forepart of the aponeurosis
of the soft palate and the under surface of the palate bone.

Nerves.—The muscles of this group receive their nerves from various
sources, some of which are not yet sufficiently determined. The stylo-pharyn-
geus receives a branch from the glosso-pharyngeal ; the constrictors are supplied
from the same and from the pharyngeal plexus. The tensor palati receives a
branch from the otic ganglion of the fifth nerve, the levator palati and azygos
uvule from the facial through the petrosal nerve of the Vidian, and the palato-
glossus and palato-pharyngeus from the palatine branches of Meckel’s ganglion.

Actions.—The muscles of the pharynx and soft palate are so arranged as to
accomplish, in conjunction with those of the tongue and hyoid bone, the action
of deglutition—that is to say, the propulsion of food into the cesophagus without
any portion being permitted to pass into the nasal cavity or larynx. while the
tongue near the fauces is thrown upwards and backwards by the stylo-glossi
muscles, and the larynx is drawn upwards and forwards under it by muscles
attached to the hyoid-bone, and by the stylo-pharyngeus muscle, so as to be both
closed by the epiglottis and overlapped by the tongue, the palato-glossi muscles
constrict the fauces and shut off the bolus from the mouth. The soft palate is
vaised and made tense by its superior muscles; the palato-pharyngei, being
approximated, nearly touch one another (the uvula lying in the small interval
between them), and prevent the passage of the food towards the upper part of
the pharynx or the posterior nares, while at the same time they form an inclined
surface for its guidance into the lower part of the pharynx. The food being
thus thrown into the grasp of the constrictors of the pharynx, those muscles
contract from above downwards and force it into the tube of the gullet below.
The Eustachian tube, according to most anatomists, is opened during degluti-
tion by the contraction of the levator palati and salpingo-pharyngeus muscles.
It should, however, be mentioned that a different view is taken by Cleland, who
holds—and with him, to some extent, Luschka agrees—that the tube is closed
during deglutition by the thickening which takes place during the contraction
of the levator palati, pressing up the membranous floor of the canal against
the firm upper and outer wall, so as completely to obliterate the opening. The
salpingo-pharyngeus, when present, assists the palato-pharyngeus and superior
constrictor in elevating the pharynx. (See Journ, of Anat., vol. iii., p. 97.)

SUBCUTANEOUS MUSCLE OF THE NECK.

The platysma myoides is a pale-coloured thin sheet of muscular
fibres, superficial to the deep cervical fascia, and extending over the
front and sides of the neck and lower portions of the side of the face.
Its fibres rise by thin bands from the clavicle and acromion, and from
the fascia covering the upper part of the deltoid, pectoral, and trapezius
muscles : thence they proceed upwards and inwards over the clavicle
and the side of the neck, gradually narrowing and approaching the
muscles of the opposite side. The greater number of the fibres are
inserted into the outer surface of the lower jaw from the symphysis to
the attachment of the masseter ; the inner fibres mingle with those of

DEEP CERVICAL FASCIA. 291

the opposite platysma in front of the symphysis, and even cross from
the one side to the other below the chin, those of the right side over-
lapping those of the left ; and the posterior fibres are prolonged upon
the side of the face as far as the angle of the mouth, blending with the
triangularis oris and orbicularis oris muscles. The uppermost fibres
(risorius, Santorini) have been already described.

Varictics——The muscular fibres of the platysma sometimes extend upwards on
the face and downwards on the neck, shoulder and breast further than usual; and
they occasionally take attachment to the clavicle. This muscle is the representa-
tive in man of a subcutaneous group of muscles, the panniculus carnosus, largely
developed in most mammals, by which very varied movements of the skin and
some superficial parts may be given, as, for example, when the horse communi-
cates a rapid motion to the skin to free itself from insects, or the dog shakes off
the water after swimming, or the hedgehog elevates its spines.

Nerves.—The platysma receives its principal motor nerves from the descend-
ing branches of the facial, but as this unites with the superficial cervical nerve
it may also be influenced through some of the spinal nerves.

Action.—The platysma, being much less developed in man than in animals has
a comparatively limited action in the human subject; it raises the skin of the
neck into longitudinal wrinkles ; it also assists in drawing the angle of the jaw
downwards and outwards, and protects parts more deeply situated in the neck. It
is contracted in sudden fear, and assists in the expression of this emotion.

MUSCLES AND FASCIA OF THE NECK ANTERIORLY.

Fascia.—The deep cervical fascia passes forwards from the anterior
border of the trapezius muscle over the sides and front of the neck
beneath the platysma myoides. Posteriorly it is continuous with the
layers of connective tissue with which the trapezius and deeper muscles
are invested ; it extends over the posterior triangle of the neck, viz.,
the space bounded by the trapezius and sterno-mastoid muscles and
the clavicle: at the posterior border of the sterno-mastoid it divides
into two layers, which form an investment for that muscle; these
unite again at the anterior border into a membrane which passes
forwards across the middle line, and covers the area bounded by the
middle line, the border of the jaw, and the sterno-mastoid muscle, and
called the anterior triangle. In the posterior triangle the fascia is
attached inferiorly to the clavicle, and near that bone is perforated by
the external jugular vein, which in the previous part of its course lies
superficial to the membrane. In the anterior triangle it is bound
superiorly to the base of the jaw in front, and further back is con-
tinued over the masseter muscle (masseteric fascia), and the parotid
gland (parotid fascia) to the zygoma.

In front the fascia is attached to the hyoid bone, and becoming
stronger as it descends, it splits, a little below the level of the
thyroid body into two distinct layers. Of these the more superficial
and weaker, running along the sterno-mastoid muscles, is fixed to the
sternum and the interclavicular ligament ; whilst the stronger layer,
lying under the former, and closely covering the sterno-hyoid and
sterno-thyroid muscles, is attached to the deeper surface of that bone.
These layers materially assist in closing the cavity of the chest behind
the sternum superiorly : between them there exists a quantity of loose
connective tissue and fat, and sometimes a small lymphatic gland.

Continuous with the deeper of those two layers, a fascia is found

u 2

292 MUSCLES OF THE HEAD AND NECK.

in the posterior triangle, investing the posterior belly of the omo-hyoid
muscle, and binding it down to the clavicle and first rib, where this
structure is connected with the costo-coracoid membrane. Still deeper
in the anterior triangle the fascia passes behind the depressor muscles
of the larynx, investing the thyroid body, and extending thence on the
trachea and large vessels at the root of the neck down to the fibrous
layer of the pericardium.

Continuous with the deep processes of the cervical fascia is the common
sheath of the large cervical blood vessels, an envelope of fascia enclosing
the carotid artery and jugular vein with the pneumogastric nerve. A
thin fibrous septum intervenes between the artery and vein, thus com-
pleting a separate sheath for each.

The layer of fascia descending on the prevertebral muscles, and inter-
vening between them and the pharynx and cesophagus, is called the
prevertebral fascia.

Muscires.—The sterno-cleido-mastoid or sterno-mastoid muscle is
attached inferiorly in two parts to the anterior surface of the sternum
and the inner third of the clavicle. The sternal attachment is thick and
rounded, tendinous in front and fleshy behind. ‘The clavicular portion,
separated from the sternal by a narrow interval, is flat, and is composed
of fleshy and tendinous fibres. Those two portions become blended
together about the middle of the neck into a thick and prominent muscle,
which, extending upwards and backwards, is attached superiorly to the
anterior border and external surface of the mastoid process, and from
thence backwards into a rough ridge of the temporal bone, and by a
thin aponeurosis into the outer part of the superior curved line of the
occipital bone. ‘The sterno-mastoid muscle divides the quadrilateral
space on each side of the neck into two great triangles.

Relations—This muscle is covered for more than the middle three-fifths of its
extent by the platysma. It is also crossed by the external jugular vein, and by
the ascending superficial branches of the cervical plexus of nerves. It rests
on part of the sterno-hyoid and sterno-thyroid muscles, and crosses the omo-hyoid
muscle ; in the middle part of the neck it covers the cervical plexus and the
great cervical vessels, and in the upper part, the digastric and stylo-hyoid muscles :
it is pierced by the spinal accessory nerve.

Varicties—The sterno-cleido-mastoid is occasionally described as two muscles,
under the names sterno-mastoid and cleido-mastoid. Normally the fibres of the
clavicular part run upwards for some distance behind and inside those of the
sternal part before finally blending with them, and sometimes they are separated
at the root of the neck by a considerable interval which is occupied by connective
tissue. The muscle varies much in breadth at the lower end, the variation
being due altogether to the clavicular part, which is sometimes as narrow as the
sternal tendon, while in other instances it extends for three inches along the
clavicle. This part of the muscle may likewise. when broader than usual, he
divided into several slips separated by intervals near the clavicle. A band of
muscular fibres has, in a few instances, been found reaching from the trapezius to
this muscle over the subclavian artery ; and the margins of the two muscles have
been observed in contact. In animals without a clavicle the cleido-mastoid
muscle is continued into the clavicular part of the great pectoral muscle, thus
forming a mastoido-humeral muscle.

The four following muscles may be classed together as a group of
DEPRESSORS OF THE Hyorp Bone AND LARYNX.

The sterno-hyoid muscle, a flat band of longitudinal fibres, arises
variously, from the sternum and the posterior sterno-clavicular ligament,
from the clavicle and that ligament, or from the clavicle only, and

INFRA-HYOID MUSCLES 293

occasionally, to a small extent, from the cartilage of the first nib tis
inserted into the lower border of the body of the hyoid bone.

Relations.—The muscle is concealed below by the sternum and the sterno-
mastoid muscle, higher up by the skin and fascia only ; it lies on the sterno-thyroid
and thyro-hyoid muscles, which it partly covers. The inner border approaches that
of the corresponding muscle towards the middle of its extent, but is separated from
it by a slight interval superiorly, and by a larger interval near the sternum ; the
outer margin is in contact with the omo-hyoid near the os hyoides. The muscular
fibres are, in many cases, interrupted by a transverse tendinous intersection.

Fig. 214.—View oF THE
SUBMAXILLARY MUSCLES
AND THE DEPRESSORS OF
tHE Hyorp BonE AND
LARYNX, FROM BEFORE.
(After Bourgery). 4
(For the explanation of

the references in the upper
part of the figure, see p.
282). ¢, body of the hyoid
bone; d, mastoid process ;
€, placed on the front of
the thyroid cartilage, points
to the thyro-hyoid muscle ;
Ff, wpper part of the ster-
num ; g, lateral lobe of the
thyroid gland ; +, its isth-
mus, above which is the cri-
coid cartilage covered by the
crico-thyroid muscle; 8,
placed on the levator sca-
pule, points to the left
middle constrictor of the
pharynx ; 9, placed on the
middle scalenus, points to
the left inferior constrictor ;
10, right sterno-hyoid; 11,
placed on the left sterno-
thyroid, points also to the
lower part of the right mus-
cle ; 12, placed on the right sterno-mastoid, points to the upper and lower bellies of
the right omo-hyoid.

The sterno-thyroid, broader and shorter than the preceding muscle,
behind which it lies, arises from the thoracic surface of the first part of
the sternum, lower down and more internally than the sterno-hyoid
muscle, and ascends, diverging a little from its fellow, to be inserted
into the oblique line on the ala of the thyroid cartilage.

Relations.—The greater part of its anterior surface is concealed by the sternum
and the sterno-hyoid muscle, as well as by the sterno-mastoid. By its deep sur-
face it rests on the innominate vein, the lower part of the common carotid artery,
the trachea, and the thyroid body. The inner margin is contiguous to the
muscle of the other side in the lower part of the neck. The median incision in
the operation of tracheotomy is made between the two muscles.

Varicties—This muscle is sometimes partly crossed by transverse or oblique
tendinous lines. At the upper extremity a few fibres are often found to blend
with the thyro-hyoid muscle or with the inferior constrictor of the pharynx.

The thyro-hyoid muscle is continued upwards from the preceding ;
it arises from the oblique line on the ala of the thyroid cartilage, and

294 MUSCLES OF THE HEAD AND NECK.

is inserted into the lower border of the body and great cornu of the
hyoid bone, near the place where these unite.

Relations—This muscle is concealed by the sterno-hyoid and omo-hyoid, and
rests on the ala of the thyroid cartilage, and on the thyro-hyoid membrane.
Between that membrane and the muscle, the superior laryngeal nerve and artery
are placed before entering the larynx.

The omo-hyoid is a long ribbon-shaped muscle, consisting of two
bellies united by an intervening tendon. It arises from the upper
border of the scapula, near the suprascapular notch, and occasionally
from the ligament which crosses the notch. Thence it extends for-
wards and only slightly upwards, across the root of the neck, till it
passes beneath the sterno-mastoid muscle, and then, curving rapidly, it
ascends nearly vertically, to be inserted into the lower border of the
body of the hyoid bone. The tendon which divides the muscle is
placed beneath the sterno-mastoid muscle, and varies much in length
and form in different bodies. The tendon is enclosed within the deep
cervical fascia, which, after forming a sort of sheath for it, is prolonged
downwards, and becomes attached to the sternum and the cartilage of
the first rib ; and by this means, as also by fascia investing the poste-
rior belly and descending to the clavicle, the muscle is maintained in
its curved position.

Relations.—At its scapular origin the muscle is covered by the trapezius, in
the middle of its course by the sterno-mastoid, and at its upper part by the
platysma; it crosses the scaleni muscles, the cervical nerves, the sheath of the
common carotid artery and jugular vein, and the sterno-thyroid and thyro-hyoid
muscles.

Varieties —The muscle occasionally is attached to the clavicle instead of the
scapula, arising from the former bone about its middle, and in such cases the
posterior belly is absent. One instance has been recorded (R. Quain) in which
the posterior belly alone was present, and was connected to the hyoid bone by a
band of fascia. The muscle has likewise been observed double, one slip being
attached to the clavicle and the other to the normal place of origin from the
scapula,

Nerves.—The sterno-mastoid receives its motor nerves from the spinal ac-
cessory, which in the substance of the muscle is reinforced by union with
branches from the second and third cervical nerves. The infra-hyoid muscles
receive their motor nerves mainly from the hypo-glossal, the thyro-hyoid by a
direct branch from the trunk of the nerve, the rest from the descendens noni,
and in part from it in combination with the communicating branches from the
second and third cervical nerves.

Actions.—The sterno-cleido-mastoid muscles acting together bend forwards
the head and neck towards the sternum. When the muscle of one side only
is in action, the head, while it is slightly flexed, is inclined laterally to the
side on which the muscle contracts, and rotation is produced, by which the face,
and especially the chin, is directed towards the opposite side. This is the
attitude in wry-neck, produced by the unequal action of the muscles of the two
sides.

While the sterno-hyoid and omo-hyoid muscles act only as depressors of the
hyoid bone, the sterno-thyroid muscle, being a direct depressor of the thyroid
cartilage, may also draw down the hyoid bone when it acts in conjunction with the
thyro-hyoid, the latter muscle elevating the larynx when the hyoid bone is fixed.
When, in the act of swallowing, the hyoid bone and thyroid cartilage have
passed suddenly upwards and forwards, their original position is restored by the
action of the infra-hyoid muscles. In the utterance of low notes the larynx and
hyoid bone descend below the natural level, in the direction of the sternal
muscles; while in the utterance of high notes there is little elevation of the

DEEP LATERAL CERVICAL MUSCLES. 295

hyoid bone, but the larynx is raised by the action of the thyro-hyoid muscles.
During deglutition the action of the thyro-hyoid muscles, by approximating the
thyroid cartilage and hyoid bone, facilitates the descent of the epiglottis on the
superior aperture of the larynx.

DEEP LATERAL AND PREVERTEBRAL MUSCLES OF THE NECK.

The scALENI muscles form a group of strong muscular columns,
which are usually three in number, but sometimes only two. All of
them are subdivided superiorly into musculo-tendinous slips, corre-
sponding in number with their vertebral attachments.

The anterior scalenus muscle is attached superiorly to the anterior
tubercles of the transverse processes of the third, fourth, fifth, and sixth
cervical vertebre, and inferiorly by a thick flattened tendon to the
scalene tubercle, a rough part of the inner border and upper surface of
the first rib in front of the subclavian groove.

Relations.—This muscle is placed deeply : in its lower part it is crossed by
the posterior belly of the omo-hyoid muscle, and in its whole length it is tra-
versed by the phrenic nerve passing obliquely from above downwards and
inwards. The subclavian vein and artery pass respectively in front and behind
its inferior attachment. The nerves of the brachial plexus emerge from behind
its outer border above the subclavian artery. The rectus capitis anticus major
arises on its inner side, the ascending cervical branch of the inferior thyroid
artery lies in the groove between that muscle and the scalenus, and in front is
the internal jugular vein.

Fig. 215.—Tux Deep LATERAL
AND PREVERTEBRAL MuUs-
CLES OF THE NECK FROM

BEFORE. (A.T.) 4

a, cut surface of the
basilar process; 06, transverse
process of the atlas; ¢, trans-
verse process of the seventh
cervical vertebra; d, body of
the first, d@’, of the fourth dor-
sal vertebra; ¢, first, and ¢’,
second rib; 1, rectus capitis
anticus major muscle; 2, rec-
tus capitis anticus minor; 3,
middle part, 3’, upper part, and
3”, lower part of the longus colli;
4, rectus lateralis; 4’, first
pair, and 4", second pair of
intertransversales ; 5, scalenus
anticus of the right side; 5’,
the tendon of attachment to
the first rib on the left side ; 6,
scalenus medius ; 6’, lower por-
tion of the corresponding mus-
cle of the left side ; 7, scalenus
posticus, its superior attach-
ments shown upon the left side ;
8, upper part of the levator
scapule drawn out from its
vertebral attachments; 9, »
splenius colli, shown in the
same manner.

The scalenus medius is attached superiorly to the posterior tubercles

296 MUSCLES OF THE HEAD AND NECK.

of the transverse processes of the last six cervical vertebree ; and
inferiorly to a rough elevation on the first rib, extending for an inch
and a half forwards from the tubercle.

Relations—In front of this muscle, between it and the anterior scalenus, are
the cervical nerves and the subclavian artery ; behind it are the posterior scalenus
and levator anguli scapulz muscles.

Varicties—This muscle sometimes arises from the transverse processes of all
the cervical vertebrae. It takes the place of the first levator costa.

The scalenus posticus, smaller than the other scaleni muscles, is
attached above by two or three small tendons to the transverse pro-
cesses of as many of the lowest cervical vertebrae, and inferiorly by an
aponeurotic tendon to the second rib, between its tubercle and angle, in
front of the attachment of the second levator cost,

Felations.—This muscle is partly covered by the middle scalene muscle, and is in
contact by its posterior surface with the levator costz and cervicalis ascendens
muscle.

Varieties.—The scaleni muscles are subject to some amount of variation, both
in the number of their points of attachment, and in the arrangement of their

fibres. A slip from the scalenus anticus sometimes passes behind the subclavian
artery.

The PREVERTEBRAL muscles of the cervical region consist of three,
of which two pass to the head from the upper vertebra, viz., the recti
capitis antici major and minor, and the third is confined to vertebral
attachments, the longus colli. Along with these ihe rectus capitis
lateralis muscle may also be described in this place.

The rectus capitis anticus major muscle arises by tendinous
slips from the anterior tubercles of the transverse processes of the
third, fourth, fifth, and sixth cervical vertebre : it is inserted into
the basilar process of the occipital bone, a little in front of the foramen
magnum. ‘The muscles of opposite sides converge as they ascend, and
their mesial fibres are longest.

Ltelations—The anterior surface of the rectus capitis anticus major supports
the pharynx, the sympathetic and vagus nerves, and the great cervical vessels.
The posterior surface rests upon part of the longus colli and the rectus anticus
minor.

The rectus capitis anticus minor, under cover of the preceding
muscle, arises from the anterior arch of the atlas, and slightly from the
root of its transverse process; it is inserted into the basilar process,
between the margin of the foramen magnum and the preceding muscle,
half an inch from its fellow.

The rectus capitis lateralis is a short thick muscle arising from
the upper surface of the anterior division of the transverse process of the
atlas, and inserted into the rough surface beneath the jugular eminence
of the occipital bone. It completes the series of intertransversales
muscles, which are described along with the deep posterior muscles of
the neck.

Relations—The anterior surface of this muscle is in contact with the internal
jugular vein, the posterior with the vertebral artery.

The longus colli muscle rests on the front of the vertebral column
from the atlas to the third dorsal vertebra : it consists of three sets of
fibres, of which two are oblique, and one vertical. a. The superior

MUSCLES OF THE TRUNK. 297

oblique portion arises, by a narrow tendinous process, from the anterior
tubercle of the body of the atlas, and is inserted into the fore part of
the transverse processes of the third, fourth, and fifth cervical vertebre.
b. The inferior oblique, the smallest part of the muscle, extends ob-
liquely downwards and inwards from the transverse processes of the
fifth and sixth cervical to the bodies of the first two or three
dorsal vertebra. c¢. The vertical part, connected by its extremities
with the other divisions, is attached superiorly to the bodies of
the second, third, and fourth cervical vertebree, and inferiorly to the
bodies of the three lower cervical and two or three upper dorsal
vertebree.

Relations —By its anterior surface this muscle is in contact with the pharynx
and cesophagus, the great vessels of the neck contained in their sheath, the sym-
pathetic and recurrent laryngeal nerves, and the inferior thyroid artery.
Behind, it rests upon the vertebre.

Nerves.—The rectus capitis anticus major and minor are supplied by branches
from the upper cervical nerves ; the longus colli and scaleni by branches of the
lower cervical nerves.

Actions.—The scalene muscles, when the vertebral column is fixed, act as
elevators of the ribs, and by many are considered as constant aids in the move-
ment of inspiration. They may also act as lateral flexors of the neck when the
ribs are fixed. The longus colli muscle is chiefly a flexor of the vertebral
column. The recti muscles are capable of producing some degree of flexion of
the head, and from the obliquity of their fibres may probably, when acting on
one side, also give rise to slight rotation.

IV.--MUSCLES AND FASCIZ OF TEE TRUNK.

The muscles passing between the trunk and the upper limb having
been already described, those which belong exclusively to the trunk
itself will now be treated of under the three divisions of, 1. Dorsal
muscles, extending throughout the whole length ; 2. Thoracic muscles,
including the diaphragm ; and 3, Abdominal and Perineal muscles.

I.—DORSAL MUSCLES AND FASCIZ.

The muscles to be described under the above head, taken as a whole,
occupy the vertebral groove or hollow between the line of vertebral
spines and the prominences formed by the mastoid processes, the trans-
verse cervical processes, the most projecting parts of the ribs, and the
crest of the ilium, and they extend from the superior curved line of the
occipital bone to the lower part of the sacrum. Some of them are
small and are limited to certain parts of the extensive region now
referred to ; others extend either continuously or by the serial repetition
of similar short fasciculi, throughout the greater part of it. These
muscles, together with those in the same region which belong more
properly to the upper limb, have been frequently described as con-
stituting six successive layers ; but the limits of several of these layers
are ill-defined, and it will be sufficient for the purpose of description
to arrange the muscles falling properly within the present section,
according to the main characteristics of their form and position, in
the following groups: viz., a, the posterior serrati muscles ; 0, the
splenius and long erectors of the spine ; ¢, the complexus and trans-
verso-spinales; d, the interspinales and intertransversales; ¢, the -

298 DORSAL MUSCLES OF THE TRUNK.

short cranio-vertebral muscles. Of these muscles those included in the
first two groups may be considered as having their fibres passing out-
wards from the middle : those in the third group as having their fibres
passing inwards ; those of the fourth group as having their fibres pass-
ing in a nearly vertical direction ; and those of the fifth group, confined
to the upper part of the vertebral column and to the head, may be
looked upon as combining some examples of the others.

SeRRATI Muscies.—The serratus posticus superior is a thin flat
muscle, which arises from the lower part of the ligamentum nuche and
from the spines of the last cervical and two or three upper dorsal
vertebree by a thin aponeurotic tendon forming about a third of the
length of the muscle ; it is inserted by four fleshy digitations into the
second, third, fourth, and fifth ribs, a little beyond their angles. It is
directed obliquely downwards and outwards, resting on the deep
muscles and the angles of the ribs. The muscle is covered, excepting
at its superior border, by the rhomboid and levator anguli scapulze
muscles.

Fig. 216.—Dorsan Mus-
CLES OF THE UPPER
Part oF THE TRUNK.
(CAST) ee

I, first; VI, sixth dor-
sal vertebra, 1, upper part
of the complexus muscle ;
2, splenius capitis ; 3, 3,
splenius colli ; 4, serratus
posticus superior ; 5, up-
per part of the longis-
simus dorsi; 5’, the same
continued up on the left
side into the transversalis
cervicis; 5", 5”, on the
right side, the transver-
salis cervicis spread out
from its attachments ; 6,
upper insertions of the
sacro-lumbalis and acces-
sorius; 6’, the same con-
tinued up on the left side
into the cervicalis ascen-
dens ; 6”, lower end of
the latter muscle of the
right side spread out from
its attachments ; 7, small
part of the spinalis dorsi ;
8, right levator anguli sca-
pule ; 8’, on the left side,
its upper part divided ;
9, three of the levatores
costarum on the right side.

The serratus posticus inferior, proader and stronger than the pre-
ceding muscle, passes outwards and upwards to the four lowest ribs ; it
arises, by a thin aponeurotic membrane from the posterior layer of the
lumbar aponeurosis, and is inserted by four fleshy digitations into the
lower borders of the last four ribs. The uppermost of those digitations
is very broad, and covers in part the second ; the last, varying in size
with the length of the twelfth rib, is entirely concealed by the rest of
the muscle (see fig. 165, p. 191). The serratus inferior is covered by

DORSAL AND LUMBAR FASCLA. 299

the latissimus dorsi, and its aponeurotic part is firmly united for some
distance with the tendon of that muscle.

Actions.—The serratus posticus superior elevates the upper ribs, and is there-
fore to be regarded as a muscle of inspiration. The serratus inferior acts directly
as a depressor of the lower ribs, and may aid either in expiration or inspiration ;
in expiration by acting in concert with the muscles which depress the higher
ribs ; in inspiration by fixing the lower ribs and giving firmness to the origin of
the diaphragm,

The vertebral aponeurosis is situated on the same plane as the
serratus posticus inferior, and consists of a thin lamella which separates
the muscles belonging to the shoulder and arm from those which sup-
port the spine and head. Its fibres are for the most part transverse ;
some however are longitudinal. Above, it passes beneath the superior
serratus ; below, it is connected with the tendons of the latissimus and
inferior serratus muscles, and in being stretched from the spinous pro-
cesses outwards across the vertebral groove, it helps to enclose the
angular space in which are lodged the long extensor muscles.

DorsaL AND LumBAR Fascta.—Under the name of lumbar fascia
or aponeurosis it has been customary to describe three layers of strong
fibrous substance sheathing the erector spinze and quadratus lumborum
muscles. The deeper parts of this structure, to which by some the
name of lumbar fascia is restricted, will be described along with the
abdominal muscles, with which they are chiefly connected. The super-
ficial or posterior layer is that through which the latissimus dorsi and
serratus posticus inferior muscles are attached to the spines of the dorsal,
lumbar and sacral vertebrae and to the crest of the ilium. This layer,
which is of considerable strength, extends outwards beyond the origin
of the latissimus and serratus inferior, and being closely united with
the middle layer, binds down firmly the erectores spinze muscles : it is
by some described as the lower part of the vertebral aponeurosis, with
which it is continuous, by others it has been named the aponeurosis of
the latissimus dorsi.

The SPLENIUS muscle is so named from its having the form of a
strap, which binds down the parts lying under it. It is attached supe-
riorly in part to the cervical vertebra, in part to the skull, and is
described accordingly under two names.

a. 'The splenius colli is attached inferiorly to the spinous processes
of the third, fourth, fifth, and sixth dorsal vertebree, and superiorly along
with the slips of the levator anguli scapulee to the transverse processes
of the first two or three cervical vertebre.

b. The splenius capitis, broader and thicker than the preceding,
arises from the spines of the seventh cervical and two upper dorsal
vertebrae, and from the ligamentum nuche as high as the third cervical
vertebrae. It is inserted into the lower and back part of the mastoid

process, and into the outer part of the superior curved line of the
occipital bone.

Relations.—The splenius is covered by the trapezius, the rhomboid, and the
serratus posticus superior ; and at its attachment to the occipital bone by the
sterno-mastoid. It conceals, in part, the complexus and trachelo-mastoid.

Erector Spina.—This muscle may either be regarded as one large
composite muscle, or as consisting of seven distinct muscles. Viewed
as one muscle it may be conveniently considered as formed of three

300 DORSAL MUSCLES OF THE TRUNK.

columns, of which the inner, or that next the spine, is comparatively
slender ; the middle and outer columns are much thicker, and consist
each of three divisions which have received separate names. |

The erector spine takes origin inferiorly as a common mass, the
outer part of which is muscular, while the inner and larger part is
tendinous. The muscular portion arises from the posterior fifth of the
crest of the ilium ; the tendinous portion arises from the back part of
the ilium, the lower and back part of the sacrum, and the sacral and
lumbar spines ; it is inseparably united below with the lumbar aponeu-
rosis, and is prolonged upwards on the surface of the muscular part,
concealing the multifidus spine. The division of the larger part into
the external and middle columns takes place below the level of the last
rib.

The three parts of the outer columns are—

a. The ilio-costalis (Theile) or sacro-lumbalis, the main muscle
of the outer column, is fleshy inferiorly, springing from that part of the
common origin which proceeds from the crest of the ilium ; it ends in
a series of tendons which incline slightly outwards, and are inserted
one into each of the six or seven lowest ribs at their angles.

6. The musculus accessorius ad ilic-costalem (ad sacro-lumba-
lem) is a continuation upwards of the preceding muscle. It arises by
flat tendons from the upper margins of the lower six ribs, internal to
the tendons of the ilio-costalis, and ends superiorly by continuing the
series of those tendons to the angles of the upper ribs.

c. The cervicalis ascendens consists of slips in serial continuation
with those of the musculus accessorius, taking origin from four or five
of the highest ribs, and inserted into the transverse processes of three
cervical vertebree, usually the fourth, fifth, and sixth. Its insertions are
intimately connected with those of the transversalis cervicis.

The middle column consists of

d. The longissimus dorsi muscle. This muscle is both larger and
longer than the ilio-costalis, its original fibres passing as high as the
first dorsal vertebree. Internally it is closely connected on the surface
with the spinalis dorsi, from the lower part of which it generally
receives one or more tendinous slips. When those slips and the
tendons of origin from the lumbar spines are cut through, the inner
surface of the muscle can be brought into view. ‘The longissimus dorsi
presents two series of insertions. The inner row of insertions is a
series of rounded tendons attached to the inferior tubercles of all the
transverse processes of the dorsal, and the accessory processes of the
lumbar vertebrae. The outer insertions form a series of thin fleshy
processes which are attached in the dorsal region to the nine or ten
lowest ribs, between their tubercles and angles, and in the lumbar
region to the whole length of the transverse processes, and beyond these
to the lumbar fascia connected with them.

e. The transversalis cervicis muscle prolongs upwards the column
of fibres of the longissimus dorsi. It arises from the internal tubercles
of the transverse processes of the four or five highest dorsal vertebra,
and occasionally the last cervical, and is inserted into the posterior
tubercles of the transverse processes of five cervical vertebra from the
second to the sixth inclusive. It always receives a slip of the original
fibres of the longissimus dorsi.

jf. The trachelo-mastoid muscle, which may be regarded as the

ERECTORES SPINA. COMPLEXUS. 302

continuation of the longissimus dorsi to the head, arises in close con-
nection with the transversalis cervicis from the upper dorsal transverse
processes, and also from behind the articular processes of the three or
four lowest cervical vertebrae, and, forming a thin flat muscle, passes to
be inserted into the posterior margin of the mastoid process, under
cover of the splenius and sterno-mastoid muscles. It is the only muscle
which lies between the splenius and complexus, and the only portion of
the erector spinee concealed by the former.

qg. The spinalis dorsi is a long narrow muscle placed at the inner
side of the longissimus dorsi, and closely connected with it. It forms
the innermost column of the erector spine. It arises by several
tendons from the spines of the first two lumbar, and the two lowest
dorsal vertebree, and is inserted into from four to eight of the higher
dorsal spines. It adheres closely to the semispinalis muscle upon which
it lies.

Actions:—The splenii and trachelo-mastoid muscles of both sides acting
together draw backwards the head and upper cervical vertebrz: when the
muscles of one side alone act, the extension is accompanied by lateral flexion
and rotation, especially of the head on the axis.

When the greater part of the erector muscles of the spine are in action on both
sides, they bend backwards the vertebral column and trunk; and these muscles
co-operate powerfully in almost every great muscular effort of the body or limbs.
Their power to straighten the back from the bent condition, as measured by the
muscular dynamometer, varies in adults of medium strength from 200 lbs. to
400 Ibs. By the action of the erector muscles of one side a certain amount of
lateral flexion and of rotation, which is greatest in the chest, accompanies the
extension. A certain amount of extension or erection of the spine, as previously
stated, accompanies inspiration ; but if the spine be fixed, some of the erector
muscles may also, by their costal attachments, depress the ribs, and thus assist in
expiration.

COMPLEXUS AND TRANSVERSO-SPINALES..-—The muscles of the com-
plicated group comprising the complexus, semispinalis, multifidus and
rotatores spine, present the feature in common of ascending with an
inward inclination, and are thus distinguished from those last described.
The most superficial, the complexus, not usually included in this group,
but obviously resembling the others, has the longest and most vertical
fibres, but is the shortest in its whole extent, being limited to the upper
dorsal and the cervical region ; the muscle beneath it, the semispinalis,
occupies the greater part of both these regions: while the multifidus
spine, extending from the sacrum to the axis, has the shortest and most
oblique fibres.

The complexus muscle arises by tendinous points from the trans-
verse processes of the seven highest dorsal and the lowest cervical
vertebree, and from the articular processes of four and sometimes five
other cervical vertebree, together with the capsular ligament uniting
them ; and it is inserted into the large internal impression between the
two curved lines of the occipital bone. It is narrower above than
below, and its inner margin in the neck is in contact with the liga-
mentum nuchz. Above its middle the muscle is partly intersected by
atendon. This portion of the muscle is often described separately,
under the name of diventer cervicis : its fibres are also frequently con-
nected by a tendinous slip with one or two of the spinous processes
belonging to the last cervical or first dorsal vertebree.

DORSAL MUSCLES OF THE TRUNK.

pe i ae ci

Fig. 217.—View or tHE
DEEP MUscLES OF THE
Back, SHOWING THEIR
ATTACHMENTS TO THE
VERTEBRAL CoLUMN AND
Riss. (A. 7.) 3

4

On the left side the seve-
ral parts of the erector spi-
ne are nearly in their na-
tural position, with the
exception of the spinalis
dorsi, which is drawn out
laterally from the spines of
the vertebra ; on the right
side the spinalis dorsi has
been entirely removed, the
ilio-costalis drawn to the
outer side so as to expose
its accessory muscle, and
the longissimus removed,
excepting small portions at
its insertions. Superiorly
on the left side, the trache-
lomastoid and complexus
are left nearly in their
natural positions ; while,
on the right side, the
trachelo-mastoid has been
entirely removed, and the
complexus, separated from
its occipital attachment,
has been spread out so as
to stretch its vertebral
attachments. a, occipital
protuberance ; 6, mastoid
process ; ¢, bifid spinous
process of the axis ver-
tebra; I, spinous process
of the first dorsal vertebra
and first rib; VI, sixth
dorsal spine and _ trans-
verse process and sixth rib ;
XII, twelfth dorsal spine
and twelfth rib. On the left
side of the figure, 1, com-
plexus muscle ; 2, trachelo-
mastoid ; 38, serratus pos-
ticus superior, detached
from the vertebral column
and drawn upwards from
the ribs ; 4, 4, the slips of
attachment of the serratus
posticus inferior to the
four lower ribs ; 5, three
slips of origin of the latis-
simus dorsi from the lower
ribs ; 5’, iliac origin of
the same muscle; 6+,
common origin of the lon-
gissimus dorsi and ilio-cos-
talis from the ilium and
sacrum, &c. ; 6, upper part
of the longissimus dorsi ;
6’, transversalis cervicis
continued up from the lon-

SEMISPINALIS. MULTIFIDUS SPINE. 303

gissimus ; 7, ilio-costalis drawn slightly inwards to show the slips of insertion into the
lumbar fascia and the various ribs ; inside the costal insertions are seen the origins of the
accessorius ; 7’, the ascendens cervicis continued upwards from the accessorius; 8, spinalis
dorsi. On the right side, 6, marks, in the lumbar region, the insertions of the longis-
simus dorsi into the upper four transverse processes (the insertion into the accessory pro-
‘cesses not being shown) ; in the dorsal region the narrower tendons of insertion into the
lower part of the dorsal transverse processes (the six lower only are represented) ; 6’, the
Series of insertions into nine ribs ; 7, the ilio-costalis drawn outwards; 7’, placed between
the lowest costal insertion of the ilio-costalis and the lowest origin of the accessorius ;
7", extension of the ascendens cervicis from the fifth rib towards the neck ; 9, 9, semi-
spinalis colli; 10, 10, semi-spinalis dorsi ; 11, 11, lower dorsal and Jumbar parts of
the multifidus spine, which appears again above the semi-spinalis colli, over the upper
9; 12, levatores costarum, long and short; 18, in the upper part of the figure, points
by four lines to the rectus capitis posticus minor, rectus major, obliquus superior, and
obliquus inferior muscles.

Feclations—The complexus muscle is covered by the splenius, except at its
lowest origins from the dorsal vertebre and at the internal portion of its upper
extremity ; the trachelo-mastoid and transversalis cervicis rest upon its series of
origins, and the semispinalis colli, the posterior recti, and the obliqui capitis,
together with the deep cervical artery, are concealed by it,

The semispinalis muscle consists of fibres extending from trans-
verse processes to spines, each bundle crossing over about five vertebrae.
It is described in two parts.

a. The semispinalis colli is the part under cover of the complexus.
It arises from the internal tubercles of the upper four or five dorsal
transverse processes, and is inserted into the spines of the cervical
vertebree from the second to the fifth inclusive being thickest at its
insertion into the second vertebra.

b. The semispinalis dorsi, not covered by the complexus, consists of
narrow muscular bundles interposed between tendons of considerable
length, and forms an elongated thin stratum, especially towards its
lower border. It arises from the transverse processes of the dorsal
vertebrae from the tenth to the fifth inclusive, and is inserted into the
spines of the last two cervical and first four dorsal vertebre.

The multifidus spine muscle reaches from the sacrum to the axis
vertebra, passing up under cover of the semispinalis, and is much more
largely developed towards the lower than at the upper end of the
column. In the sacral region the fibres arise from the deep surface of
the tendinous origin of the erector spine, from the groove on the back
of the sacrum as low as the fourth foramen, from the inner part of the
posterior extremity of the iliac crest, and from the ligaments between
that bone and the sacrum ; in the lumbar region they take origin from
the mammillary processes ; in the dorsal region from the transverse
processes ; and in the neck from the articular processes of the four
lower cervical vertebre. From these several points the muscular
bundles ascend obliquely, to be inserted into the laminz of the vertebree,
and into the spines from their bases nearly to their extremities. The
fibres from each point of origin are fixed to several vertebrae, some
being inserted into the side of the spinous process next above, and
others ascending more and more vertically as high as the fourth from
the place of origin ; the longer fibres from one origin overlapping those
from the origin next above.

The rotatores spinz are eleven pairs of small muscles, which may
be regarded as the deepest fibres of the multifidus spine in the dorsal

304 DORSAL MUSCLES OF THE TRUNK.

region, and are distinguished by being more nearly horizontal than the
rest. Each arises from the upper and back part of the transverse pro-
cess, and is inserted into the vertebra next above, at the inferior margin
and on part of the surface of the lamina, as far as the root of the
spinous process.
INTERTRANSVERSALES.—The intertransversales are short muscies
passing nearly vertically from vertebra to vertebra between the trans-
verse processes. They are most developed in the cervical, and least in
the dorsal region. Beneath each cervical transverse process there are
two such muscles, one descending from the anterior, and another from
the posterior part of the process. In the lumbar region there are like-
wise two sets: one set, the znfertransversales laterales, lie between the
transverse processes, and are in series with the levatores costarum ; the
other set, indertransversales mediales or interaccessorii, pass from the
accessory process of one vertebra
to the mammillary process of

the next, and are in series with
the intertransversales of the dor-
sal region

Fig. 218.— View or tHe Dexr Pos-
TERIOR MuscLes or THE Upper Part
OF THE VERTEBRAL Cotumn. (A. T.} 4

a, posterior occipital protuberance ; 0,
surface between the superior and in-
ferior curved lines on which the com-
plexus is inserted ; ¢, spinous process of
the axis vertebra; d, transverse pro-
cess of the atlas; e, transverse process
of the first dorsal vertebra ; 7, lamina of
the sixth dorsal vertebra; 1, rectus
capitis posticus minor muscle ; 2, rectus
posticus major; 3, obliquus superior ;
4, obliquus inferior; 5, rectus capitis
lateralis ; 6, trachelo-mastoid, the mus-
cle of the right side turned inwards and
its slips of attachment to the dorsal and
cervical transverse processes separated:
from each other; 7, transversalis cer-
vicis, the figures are placed near the
extreme ends of the muscle on the right
side; 7’, on the left side, longissimus
dorsi; 8, cervicalis ascendens, the
muscle of the right side is spread out ,
8’, on the left side, the seven upper
tendinous insertions of the ilio-costalis
and accessorius muscles ; 9, upper part
of the semispinalis colli of the left side ;
10, placed on the seventh rib of the right
side close to the insertion of its levator
cost muscle ; 11, 11, three rotatores
vertebrarum between the third and sixth
dorsal vertebree.

: INTERSPINALES.—The inter-

spinales are short vertical fasci-

culi of fleshy fibres, placed in pairs between the spinous processes of the
contiguous vertebre. They are best marked in the neck, where they are

SHORT CRANIO-VERTEBRAL MUSCLES. 805

connected one to each of the two parts into which the spinous process
is divided. In the dorsal part of the column only a few are met with,
and these are not constant.

Varictics.—The spinalis cervicis consists of a few irregular bundles of fibres,
of greater length than the preceding muscles, placed close to the ligamentum
nuchz: they arise by two or more heads from the spines of the fifth and sixth
cervical and sometimes other neighbouring vertebre, and are inserted into the
spine of the axis, and occasionally into the two vertebre next below it. This
muscle is sometimes wanting. (See Henle and Heilenbeck, in Miiller’s “ Archiv,”
1837.

Th name sacro-coccygeus posticus, or extensor coccygis, has been given to
slender fibres occasionally found extending from the lower end of the sacrum to
the coccyx, and representing the extensor of the caudal vertebre of other
animals. (Giimther and Milde, “ Chirurgische Muskellehre,” quoted by Theile,
“ Sommerring vom Baue,” &c.)

SHort PosTeRIOR CRANIO-VERTEBRAL MusciEs.—The reetus
capitis posticus major muscle arises by a narrow tendon from the
spinous process of the axis, and expanding as it passes upwards and
outwards, is inserted into and beneath the outer part of the inferior
curved line of the occipital bone. Its insertion is inside and below
that of the superior oblique muscle.

The rectus capitis posticus minor muscle arises from the posterior
arch of the atlas by the side of the tubercle, and expands as it passes
to be inserted into the inferior curved line of the occipital bone, and
the rough surface between that and the foramen magnum.

The obliquus capitis inferior, the strongest of the muscles now
under consideration, arises from the spinous process of the axis, between
the origin of the rectus posticus major and the insertion of the semi-
spinalis colli, and is inserted into the extremity of the transverse
process of the atlas.

The obliquus capitis superior, smaller than the preceding muscle,
arises from the upper surface of the transverse process of the atlas,
inclines from thence obliquely upwards and backwards, increasing some-
what as it ascends, and is inserted into a groove situated externally to
the inferior curved line of the occipital bone.

Relations.—The two oblique muscles with the rectus major, form the sides of
a small triangular space, in the area of which the posterior primary branch of
the sub-occipital nerve and the vertebral artery will be found.

Nerves.—All the muscles of the back which are unconnected with the upper
limb, viz., the posterior serrati, splenius, complexus, erector spinz, and the muscles
more deeply seated are supplied by the posterior primary branches of the spinal
nerves.

Actions.—The transverso-spinales muscles, including the complexus, are essen-
tially ext ensors of the head and vertebral column ; and the movements produced
by them vary according as the muscles of one side or both are in action, in a
manner similar to that already pointed out in regard to the erector muscles.

The interspinales and intertransversales muscles approximate the vertebra
between which they pass, and thus may act as extensors and lateral flexors
respectively of the portion of the vertebral column in which they are situated.

Of the four muscles last described, two—the rectus minor and superior oblique
—act principally by drawing the head backwards, that being the chief movement
allowed between the atlas and occipital bone; while the principal action of the
rectus posticus major and the inferior oblique, when acting on one side, is to
rotate the atlas and skull upon the axis,

VOL. I. x

306 MUSCLES OF THE THORAX.

MUSCLES OF THE THORAX.

The muscles of the thoracic wall are the intercostales, levatores cos-
tarum, subcostales, and triangularis sterni, and along with these the
diaphragm intervening between the thorax and abdomen may con-
veniently be grouped.

The INTERCOSTAL MUSCLES consist of two thin layers of oblique short
muscular fibres filling up the intercostal spaces : these layers are named
respectively the external and internal muscles.

Fig. 219.—Vrew oF SEVERAL OF THE Mippie Dorsat VERTEBRHZ AND Ribs, TO SHOW
tue IntERcostaL Muscues (after Cloquet), (A. 7.) 3

A, from the side ; B, from behind.

IV, the fourth dorsal vertebra ; V, V, the fifth rib and its cartilage ; 1, 1, the levatores
eostarum muscles, short and long ; 2, the external intercostal muscles ; 3, the internal
intercostal layer shown, in the lower of the two spaces represented, by the removal of the
external layer, and seen in A in the upper space, in front of the external layer: the
deficiency of the internal layer towards the vertebral column is shown in B,

The external intercostal muscles, consisting of muscular with
some tendinous fibres intermixed, are directed obliquely downwards
and forwards from one rib to another. ‘Their extent for the most
part is from the tubercles of the ribs, nearly to the outer end of the
cartilages ; but in the two lowest intervals they reach forwards to the
ends of the spaces. ‘Thin tendinous fibres, having the same direction
as the external intercostal muscles, are continued forwards between the
costal cartilages, from the points where the muscles cease, to the
sternum, and there cover the internal intercostals.

The internal intercostal muscles, placed deeper than the preceding,
are attached to the inner margins of the ribs and their cartilages.

INTERCOSTAL MUSCLES. 307

Commencing at the anterior extremities of the cartilages of the ribs,
they extend as far back as a point within the angles of those bones.
The fibres incline downwards and backwards, crossing’ those of the
external intercostals; they are, however, somewhat shorter and less
oblique in their direction.

Relations.—The internal are separated from the external intercostal muscles at
the back of the spaces by the intercostal vessels and nerves; they are lined
internally by the pleura.

Fig. 220.—View or ran Deep Mvscirs or tun Anrertor Watt or THE THORAX, SEEN
FROM BEHIND (modified from Luschka). (A.T.) 43

a, back of the manubrium of the sternum ; 4, clavicles ; I to XI, the anterior parts
of eleven ribs and costal cartilages ; 1, 1’, sterno-thyroid muscles, that of the right side
being ctit short to show more fully the next muscle ; 2, 2’, the sterno-hyoids ; 3, trian-
gularis sterni ; 4, upper part of transyersalis abdominis united in 4’, 4’, the back of the
Jinea alba ; 5, attachments of the diaphragm to the lower ribs (the twelfth not represented
in the figure), indigitating with those of the transversalis ; 5’, the two slips to the ensi-
form process ; 6, internal layer of intercostal muscles extending to the sternum, shown
in all the spaces on the right side, but only in the two uppermost of the left side ; 7, in
the lower spaces of the left side, indicates the external layer of intercostal muscles
exposed by removing the internal layer.

xe

308 MUSCLES OF THE THORAX.

The levatores costarum, twelve on each side, arise from the tips of
the transverse processes of the seventh cervical and eleven highest
dorsal vertebree. Corresponding in direction with the external inter-
costal muscles, on which they lie, they pass downwards and outwards,
spreading as they descend, and each is inserted into the outer surface of
the rib belonging to the vertebra below that from which it springs.
The levator muscles belonging to the lower ribs present some longer
additional fibres which, passing over a rib, are inserted into the next
one below ; these fibres are sometimes distinguished as levatores cos-
tarum longiores.

Relations —The levatores costarum lie in series superiorly with the scaleni
medius and posticus, and inferiorly with the lateral lumbar intertransverse
muscles.

The subcostal muscles are small bundles lying on the inner aspect
of the thoracic wall, close to the surface of the internal intercostals,
and chiefly in the neighbourhood of the angles of the ribs. They
follow the same direction as the internal intercostal muscles, but their
fibres extend over one or two intercostal spaces. ‘They are most
constant on the lower ribs (see fig. 221).

The triangularis sterni, a thin stratum of muscular and tendinous
fibres placed within the thorax, behind the costal cartilages, arises from
the deep surface of the ensiform process of the lower part of the body of
the sternum, and of the cartilages of one or two of the lower true ribs.
Its fibres pass outward and upwards in a diverging manner, the lowest
being horizontal, the middle oblique, and the upper becoming more and
more nearly vertical ; they are inserted by separate slips into the carti-
lages of the true ribs from the sixth to the second inclusive, on the
lower border and inner surface of each, at the junction with the bony
part. At the lower margin the fibres are in the same plane with those
of the transversalis abdominis, of which the triangularis sterni muscle
is a continuation upwards.

Relations —The internal mammary artery and veins pass between its anterior
surface and the costal cartilages ; the pleura is in contact with its deep surface.

Varieties —The triangularis sterni is subject to much variation as to its extent
and points of attachment in different bodies, and even on the opposite sides of
the same body. The subcostales also vary greatly in their extent in different
subjects.

The rectus sternalis, or sternalis brutorwm, is an elongated muscle,:of nearly
the same length as the sternum, frequently seen lying in front and parallel to the
outer margin of that bone, and over the inner part of the pectoral muscle. Itis
fleshy in the middle and tendinous at both ends; it is attached superiorly to the
sternum in connection with the tendon of the sterno-mastoid, and inferiorly it is
connected with the rectus abdominis muscle, It is rarely present on both sides,
It represents a muscle which is constant in some animals,

THE DIAPHRAGM.

The diaphragm, or midriff, forms a musculo-tendinous partition
between the abdominal and thoracic cavities. It consists of muscular
fibres which arch upwards as they converge from the circumference of
the visceral cavity to a tendinous structure in the centre, and it is
abe by the various structures which pass from the thorax to the
abdomen.

THE DIAPHRAGM. 309

The fibres arise from the bodies of several of the upper lumbar
vertebree by two thick crura ; from two arches on each side external to
the bodies of the vertebrae, called ligamenta arcuata; and from the
ensiform cartilage and the cartilages of the six lower ribs.

a. The crura arise by tendinous fibres aggregated into two bundles,
from the first, second, and third lumbar vertebree, and the interposed
fibro-cartilages on the right side, and from the first and second ver-
tebree on the left side. The tendons of both crura curve forwards
and upwards so as to enclose the aorta in an arch between them and
the bodies of the vertebrae ; their inner margins are united behind, so
that they form a nearly complete fibrous ring or oval loop round that
vessel. The muscular fibres of the crura, springing from those tendons
in thick bundles, on each side of the aorta, diverge as they pass upwards
to the central aponeurosis. The innermost fibres on each side decussate
with those of the side opposite, those of the right usually lying anterior
to those of the left, and, curving upwards, limit an opening for the
transmission of the cesophagus, before ending in the central apo-
neurosis.

Fig. 221.—Tur Lower Har or
THE THORAX, WITH FouR Lum-
BAR VERTEBREZ, SHOWING THE
DIAPHRAGM FROM BEFORE (modi-
fied from Luschka). (A. T.) 4

a, sixth dorsal vertebra; 3,
fourth lumbar vertebra ; ¢, ensi
form process of the sternum; d,
the aorta descending in front of
the lower dorsal vertebre ; d’, the
aorta emerging in the abdomen
below the arch formed by the
meeting of the pillars of the dia-
phragm; e, the cesophagus de-
scending through its aperture in
the diaphragm ; f, opening in the
tendon of the diaphragm for the
inferior vena cava; 1, central, 2,
right, and 3, left division of the
trefoil tendon of the diaphragm ;
4, right, and 5, left muscular part,
descending from the margins of the
tendon to be attached to the ribs ;
6, the right, and 7, the left crus
or pillar of the muscle; 8, to 8’,
in the three upper intercostal spaces
of the right side the internal
layer of intercostal muscles inter-
rupted towards the vertebral co-
lumn, where in the two upper
spaces the external layer, 9, 9, is
seen; 10, 10, on the left side,
subcostal muscles.

b. The ligamentum arcuatum internum is a fibrous band which
extends from the body to the transverse process of the first lumbar
vertebra, and sometimes also to that of the second, and arches over the
upper part of the psoas muscle. The ligamentum arcuatum externum
extends outwards from the transverse process of the first lumbar

310: MUSCLES OF THE THORAX.

vertebra to the last rib, arching over the front of the quadratus Iumbo-
rum: it is the upper part of the fascia covering that muscle, somewhat
increased in thickness. From both ligamenta arcuata diaphragmatic
muscular fibres take their origin, and are directed upwards to the
posterior part of the tendinous centre.

Fig. 222.—View oF THE
DIAPHRAGM, FROM BE-
LOW. “(CAs 1.) ee

In the preparation from
which this figure is drawn,
the lower ribs and sternum
are thrown upwards so as
to expose and stretch the
lower surface of the dia-
phragm, and the four
upper lumbar vertebrie
haye been exposed by the
removal of all the muscles
on the right side, and the
dissection of the psoas mag-
nus and quadratus lumbo-
rum on the left side. a,

, the aorta emerging in the
\\E"” \\\ \ ih HAAN Noo abdomen from between the
/ VAR | Z Bimini \ WN pillars on the first lumbar
N97 \\ A vertebra ; 6, the cesopha-
gus, in its aperture between
the muscular crura, repre-
sented too far to the right ;
c, the aperture for the
vena cava inferior situated
at the place of union of the
middle and right divisions
of the trefoil tendon; d, the
body of the fourth Jumbar
vertebra ; e, ¢, the twelfth
ribs near their extremities ;
F, f, the ends of the eleventh
ribs ; 1, the tendinous part of the right crus ; 2, the left; 8, the tendinous arch formed
by their union over the aorta, above which the decussation of muscular fibres is seen ;
4, second decussation of muscular fibres in front of the cesophageal opening ; 5, on the
right side, placed near the end of the transverse process of the first lumbar vertebra,
towards which, arching from above and from within, over the +, is seen the ligamentum
arcuatum internum ; and from which, passing towards e, is seen the ligamentum arcua-
tum externum ; 5’, on the left side, is in a similar position, but here the quadratus
lumborum muscle is seen descending from the twelfth rib behind the ligamentum arcuatum
externum, and the upper part of the psoas muscle is within the ligamentum arcuatum
internum ; 6, the middle division of the trefoil tendon, from which in front pass the
slips of attachment of the diaphragm to the ensiform process ; 7, the left, and 8, the
right divisions of the trefoil tendon ; from the outer and anterior margins of these the
costal slips of the muscle are seen diverging, and from the posterior border of the tendon
the slips of origin proceeding from the ligamenta arcuata and the tendinous arch of the
crura ; 9, part of the quadratus lumborum ; 10, part of the psoas magnus.

EZ AA = pees, \ i i}
LZ ee Wy
ZAP ZZ }

c. The fibres arising from the cartilages of the six lower ribs form a
serics of serrated slips interdigitating with the attachments of the trans-
versalis abdominis muscle. They sometimes arise also in part from the
osseous ribs. ‘The fibres proceeding from the ensiform cartilage form
a narrow slip, sometimes divided into two, on each side of which there
occurs an interval, in which the lining membranes of the thorax and

THE DIAPHRAGM. 311

abdomen are separated only by a small quantity of loose connective
tissue. The anterior fibres of the diaphragm are much the shortest.
The fibres of the sternal and costal slips, after being united, rise in an
arched and converging manner to be inserted into the anterior and
external margins of the central tendon.

d. The central tendon—trefoil or cordiform tendon, is a strong aponeu-
rosis, forming the central and highest part of the diaphragm. It is
elongated from side to side, and consists of three lobes or ale, partly
separated by indentations. The right lobe is the largest ; and the
left, which is elongated and narrow, is the smallest of the three. The
central tendon is surrounded on every side by the muscular portion of
the diaphragm, the fibres of which are directly continuous with those of
the tendon. The tendinous fibres cross one another, and are inter-
woven in various directions.

Foramina—There are in the diaphragm three large perforations for
the passage respectively of the aorta, the cesophagus, and the vena
cava, besides some smaller holes or fissures which are less regular.
a. The foramen for the aorta (Aiatus aorticus), placed in front of the
vertebrae, is bounded by tendinous fibres of the crura as already de-
scribed. Besides the aorta, this opening transmits the thoracic duct,
and generally also the vena azygos. 6. The foramen for the ceso-
phagus, higher and farther forward than the preceding, as well as a
little to its left, is separated from that opening by the decussating
fibres of the crura. It is oval in form, and is generally entirely sur-
rounded by muscular fibres ; in some rare cases, however, a small part,
the anterior margin, is found to be tendinous, being formed by the
margin of the central tendon. c¢. The opening for the vena cava
(foramen quadratum) is placed in the highest part of the diaphragm, in
the tendinous centre at the junction of the right and middle als, poste-
riorly. Its form is somewhat quadrangular ; and it is bounded by
fasciculi of tendinous fibres running parallel with its sides. Besides
the foregoing large foramina there are small perforations through the
crura for the sympathetic and splanchnic nerves on both sides, and for
the vena azygos minor on the left side. Moreover, the larger azygos
vein often takes its course through the right crus.

Relations.—The upper or thoracic surface of the diaphragm is highly arched.
Its posterior and lateral fibres, ascending from their connection with the lower
Margin of the thorax, are for a considerable extent placed close to the ribs, the
lungs, especially in their collapsed condition, not descending so far as their
attachments. The vault of the diaphragm rises higher on the right than on the
left side. On the right side in the dead body it rises to the level of the fifth
rib at the sternum, and on the left side only as high as the sixth. This difference
has relation to the great size and firmness of the liver on the right side. It
is covered superiorly by the pleura and the pericardium ; the fibrous layer of
the latter membrane blending with the tendinous centre, as well as with the
fascia covering its muscular substance. The lower surface, of a deeply concave
form, is lined by the peritoneum, and has in apposition with it the liver, the
stomach, the pancreas and spleen, and the kidneys,

Nerves.—The intercostals, subcostals, levatores costarum and _ triangularis
sterni are supplied by the intercostal nerves. The diaphragm is supplied by the
phrenic nerves from the fourth and fifth cervical nerves, and likewise by sympa-
thetic filaments from the plexuses round the phrenic arteries,

Actions.—Movements of Respiration.—The mechanical act of respiration

312 MUSCLES OF THE THORAX.

consists of two sets of movements, viz., those of inspiration and of expiration, in
which air is successively drawn into the lungs and expelled from them by the
alternate increase and diminution of the thoracic cavity. The changes in the
capacity of the thorax are effected by the expansion and contraction of its lateral
walls, called costal respiration, and by the depression and elevation of the floor of
the cavity, through contraction and relaxation of the diaphragm, called abdominal
respiration. 'These two movements are normally combined in the act of respira-
tion, but in different circumstances one of them is resorted to more than another.
Thus, abdominal respiration is most employed in the male, costal respiration most
in the female.

Inspiration —The study of the movements of the thoracic walls in respiration
presents considerable difficulty from the complexity of these movements, and
from the impossibility of perfectly imitating in the dead body the mechanical
conditions under which they occur in life. On the prepared skeleton, by raising
and depressing the sternum the ribs may be moved upwards and downwards
nearly parallel to one another ; the first rib moving as freely as the others. But
during life several causes combine to make the first rib more fixed than those
which follow : as for example, the weight of the upper extremity, and the strain
of the intercostal muscles and ribs beneath. The movements of the thoracic
walls in respiration are as follows: Ist. The antero-posterior diameter is increased
by a forward movement of the sternum with the attached ribs and cartilages ; the
lower end of the sternum is raised and advanced, while the upper end, which in
easy respiration is at rest, or nearly so, is only raised in full inspiration. 2nd.
The lateral diameter of the thorax is increased by the elevation and the rotation
of the ribs ; the first of these movements bringing larger costal arches to a level
occupied in expiration by smaller arches above them ; and the second, by the
rotation of the ribs round an axis extending from their vertebral extremities
to the sternum, which everts the lower edge of the ribs, and increases the width
of their arch outwards. 3rd. The capacity of the thorax, transversely and
antero-posteriorly, is increased by the elastic bending of the ribs, as well as the
opening of the angle between the ribs and their cartilages, produced by the
resistance of the sternum and weight of the limbs to the forward and upward
motion of the extremities of the cartilages, and by the inclination backwards
given to the middle ribs in their upward movement by the oblique direction of
the plane of the costo-transverse articular surfaces. 4th. The vertical diameter
of the thoracic cavity is increased by the descent of the platform of the dia-
phragm forming its floor; but as any considerable elevation of the ribs would
tend to diminish the capacity of the thorax in inspiration, the lowest ribs
are drawn backwards and outwards rather than raised. Lastly, it may be re-
marked, that extension of the vertebral column is an important agent in respira-
tion, for when the column is bent forwards, the ribs are pressed together in the
concavity of the curve, and, conversely, when the column is extended the ribs
are separated.

Action of the Intercostal Muscles —The manner in which these muscles act has
been a subject of controversy from an early time, and is not yet thoroughly deter-
mined, Among those who look upon the intercostal muscles as active in respira-
tion, all are agreed that the external muscles are elevators of the ribs, and
therefore muscles of inspiration. According to one view, defended by Haller, the
external and internal layers have a common action, the decussating fibres acting
in the direction of the diagonal between them ; while according to another view,
that of Hamberger, the external intercostal muscles are admitted to be elevators,
but the whole internal are held to be depressors of the ribs. More recently these
views have been modified by Hutchinson to the extent of admitting that the
external intercostal muscles, and the parts of the internal intercostals placed
between the costal cartilages, elevate the ribs, and that the lateral portions of
the internal intercostals act as depressors. This view is illustrated mechanically,
and supposed by some to be demonstrated, by means of a mechanism of rods
and elastic bands imitating the conditions of the ribs. But the ribs differ from
such rods in respect that they are not straight or rigid bars, and are not
free at either end, but are deeply curved, and have the greatest extent of

ACTION OF INSPIRATORY MUSCLES. 313

motion in the middle of their arch ; and in the living subject, the ribs, in their
elevation, both rotate upon their axis and bend upon themselves, instead of
describing a simple upward and downward movement like the bars, so that
it is impossible to draw any certain conclusion from such imperfect imitations
of the mechanism. On the whole, the deficiency of the external intercostal
muscles in front and of the internal behind, in which situations they would have
acted as depressors, seems to point to a combined action of the muscles as eleva-
tors of the ribs in the manner maintained by Haller. This view is farther
supported by the result of experiments on the galvanic stimulation of the
intercostal muscles. Thus Duchenne found (Physiol. des Mouvements, &c., p.
647) that the direct galvanic stimulation of the external intercostal muscles
throughout the fifth space caused the lower ribs to rise; towards the upper, and
likewise that the stimulation of the internal intercostal muscles in the inter-
cartilaginous part of the space also caused the lower rib to rise, and he farther
found that when the galvanic stimulus was so strong as to reach the intercostal
nerve, and throw the whole of the internal as well as the external intercostal
muscles into action, the lower ribs were still elevated. These results received
additional confirmation from the pathological observation that in cases of
paralysis of the diaphragm and the auxiliary muscles of inspiration the ribs were
raised by the sole action of the intercostal muscles, and that in other cases in
which the intercostal muscles were paralysed, while the diaphragm retained its
power, the expansion of the upper ribs was entirely abolished.

Among the more recent anatomical writers, Henle inclines to Haller’s view ;
Luschka refers to Budge’s experiments on the muscles of living animals, as
proving that the internal intercostal muscles elevate the ribs (Budge, ‘“* Lehrbuch
der Physiologie des Menschen,” Weimar, 1860, p. 79).

The levatores costarum have a similar action with the posterior fibres of the
external intercostal muscles, and ought therefore to be ranked among the agents
of inspiration. The scalene muscles also are usually believed to contribute, even
in normal and quiet inspiration, to the support and elevation of the first and
second ribs and it is obvious that the serratus posticus superior must have a
similar effect on those upper ribs to which it is attached.

The action of the diaphragm is more easily understood than that of the inter-
costal muscles. By its contraction and descent its convexity is diminished, the
abdominal viscera are pressed downwards, and the thorax expanded vertically.
The fibres arising from the lowest ribs, being directed nearly vertically upwards
from their costal attachments, must tend to pull those ribs upwards. Duchenne
has shown that the contraction of the diaphragm by itself elevates and expands
the lower ribs, but only so long as the vault of the muscle is supported by the
abdominal viscera, for when they are removed it no longer has that action (op.
cit. p. 620). The serratus posticus inferior and quadratus lumborum muscles, by
opposing the diaphragm, and thus giving it a fixed point on which to descend,
become assistant muscles of inspiration. The anterior fibres of the diaphragm
being directed moze horizontally towards the central tendon, oppose the forward
motion of the sternum ; hence the sternum becomes arched in patients long
subject to asthma. (Hutchinson, Article “ Thorax,’ in Todas “ Cyclopedia of
Anatomy and Physiology ;” Meyer, “ Physiclogische Anatomie.’’)

In more forcible inspiration, and more especially in severe attacks of dyspnoea,
there are called into play other powerful mzscles, to secure the inspiratory action
of which a fixed attachment mrst be provided by the supporé and elevation of
the shoulder and arm ; among these may be enumerated the serratus magnus and
pectoralis minor, acting from the shoulder, and the pectoralis major and latissimus
dorsi, acting from the raised arm, which together produce expansion and eleva-
tion of the ribs.

Expiration —In normal and quiet expiration the diminution of the capacity
of the chest is mainly, if not wholly due to the return of the walls of the
chest to the condition of rest, in consequence of their own elastic re-action, and
of the elasticity and weight of the viscera and other parts displaced by inspira-
tion ; the lungs themselves, after distension by air, exert considerable elastic
force, and no doubt the ribs and their cartilages react strongly by their elastic _

314 MUSCLES AND FASCIA OF THE ABDOMEN.

return from the elevated and bent condition into which they had been thrown
by the inspiratory forces. In more forcible acts of expiration, in muscular
efforts of the limbs and trunk, and in efforts of expulsion from the thoracic and
abdominal cavities, all the muscles which tend to depress the ribs, and those
which compress the abdominal cavity, concur in powerful action to empty the
lungs, to fix the trunk, and to expel the contents of the abdominal viscera, (See
further, ‘ Action of the Abdominal Muscles.”’)

MUSCLES AND FASCIZ OF THE ABDOMEN.

Fascta.—The superficial fascia of the abdomen is_ usually
described as consisting of two layers. One of these, the subcutaneous
layer, corresponds in its general features with the areolar subcutaneous
tissue of other parts of the body, and contains embedded in it a very
variable and often large quantity of fat. The other, or deeper layer, is
of a denser and more membranous structure, contains a considerable
amount of yellow elastic tissue in its substance, and is united by
intervening fibres, in some places very closely, to the aponeurosis of
the external oblique muscle. These two layers are both continuous
with the superficial fascia on other parts of the trunk: they can be
dissected as distinct layers only on the fore part of the abdomen, and
are separated in a more marked manner in the lower part of its wall,
where subcutaneous vessels, such as the superficial epigastric and cir-
cumflex iliac, lie between them. The deep or elastic layer of the
superficial fascia is bound down by a thin but dense intervening layer
of fibrous tissue to the aponeurosis of the external oblique muscle in
two places more particularly, viz., along the linea alba from the um-
bilicus to the pubis, and in the whole length of Poupart’s ligament.
At the lower part of the linea alba it sends fibrous and elastic processes
towards the dorsum of the penis, which form its so-called suspensory
ligaments. By its close union to Poupart’s ligament, it comes into
relation with the fascia lata of the thigh, which is also united to that
structure : but in the neighbourhood of the external inguinal aperture
it remains free, and is prolonged downwards over the spermatic cord
to the scrotum. The subcutaneous layer, losing its fat, is combined
with the deeper layer as they both pass to the scrotum ; and here the
united layer acquires a reddish brown colour, and undergoing a
modification in structure by being mingled largely with involuntary
muscular fibres, constitutes the dartos tunic of the scrotum. Some
involuntary muscular fibres also exist in the altered superficial fascia
which covers the penis. This covering, on leaving the scrotum poste-
riorly, becomes continuous with the superficial fascia of the perineum.

The parts of the superficial fascia here described have received minute attention
from surgical anatomists, because of their close relation to the seat of hernial
tumours ; the adhesion of the fascia to Poupart’s ligament, and its disposition
over the inguinal aperture, spermatic cord, and scrotum, while they prevent the
descent upon the thigh of matter which has been effused beneath the fascia,
cause it rather to spread upwards upon the abdomen or to take its course down-
wards upon the scrotum.

The deep layer of the abdominal fascia is also interesting, as corresponding
with the tunica abdominalis, a strong membrane consisting almost entirely of
yellow elastic tissue, which exists in animals, as may be well seen in the horse
or ox, and which contributes to the support of the viscera.

Muscuires.—The muscular wall of the abdomen is formed for the most

ABDOMINAL FASCILZ. 315

part on each side, of three layers of muscle, the fibres of which run in
different directions ; those of the two most superficial layers being
oblique, and those of the innermost layer being transverse. In front
those three layers of muscle are replaced by tendinous expansions, which
meet in the middle line; on either side of that line the fibres of the
recti muscles extend in a vertical direction between the tendinous
layers, supported usually at the lower end by the pyramidales muscles.
Posteriorly the wall is formed in part by aponeurosis, and in part by
muscles of which the fibres are chiefly vertical, viz., the muscles of the
back, and in front of them the quadratus lumborum.

Fig, 223.—SuprrriciaL View or THE Muscins oF THE ABDOMEN, FROM BEFORE.
(Av D:)) 2
a Ds) ) 32

14, external oblique muscle ; 15, is placed on the ensiform cartilage at the upper end
of the linea alba ; 15’, umbilicus ; 16, symphysis pubis at the lower end of the linea
alba ; above 16, the pyramidales muscles are seen shining through the abdominal
aponeurosis ; from the upper 14 to 17, the linea semilunaris; between this line and the linea
alba are seen the transverse lines of the rectus muscle ; above 22, the curved margin of
Poupart’s ligament ; on either side of 16, the external abdominal ring is indicated.

The abdominis externus obliquus muscle arises from the outer

316 MUSCLES OF THE ABDOMEN.

surface of the eight inferior ribs, by slips arranged in a serrated series,
four or five of them meeting with origins of the serratus magnus, and
three or four with origins of the latissimus dorsi. The slips of these
two sets of muscles alternate with each other, as the tips of the fingers
of one hand may be made to fit in between those of the other, and
hence they are said to interdigitate, and are termed digitations. The
lower and upper digitations of the external oblique are connected with
the ribs near their cartilages, the others are attached to the ribs at
some distance from their extremities ; the lowest digitation generally
embraces the point of the twelfth rib. ‘The fleshy fibres from the last
ribs pass down in nearly a vertical direction to be inserted into the ex-
ternal margin of the crest of the ilium for about the anterior half of
its length ; all the rest incline downwards and forwards, and terminate
in tendinous fibres, which form the broad aponeurosis by which the
muscle is inserted.

The aponeurosis of the external oblique muscle, wider at the lower
than at the upper part, and larger than that of either of the subjacent
abdominal muscles, extends inwards towards the middle line in front ;
at some distance from this, but farther out above than below, it becomes
inseparably united with the aponeurosis beneath, and forms a part of
the sheath of the rectus muscle in the whole extent of the space from
the ensiform cartilage to the symphysis pubis. The upper part of the
aponeurosis is connected externally with the larger pectoral muscle.
Its lower fibres are closely aggregated together, and extend across from
the anterior superior iliac spine to the spine of the pubis, in the form
of a broad band, which is called Powparl’s ligament. This band is curved
at the middle and outer parts, the convexity of the curve being directed
towards the thigh, a form which is given to it by its connection with
the fascia lata of the limb.

Above the crest of the pubis the fibres of the aponeurosis, separating
from the imner part of Poupart’s ligament, leave between them an
oblique opening, the superficial or external abdominal ring, through
which passes the spermatic cord in the male and the round liga-
ment in the female. The direction of this opening is upwards and
outwards, its base being formed by the pubic crest, and its sides by the
two sets of diverging fibres called the pi//ars. ‘The upper or internal
pillar is attached to the anterior surface of the symphysis pubis, inter-
lacing with the corresponding fibres of the opposite side ; the lower
or external pillar is formed by Poupart’s ligament, near its attach-
ment to the spine of the pubic bone. The inner pillar is flat and
straight, but the outer, especially near its attachment to the pubis, is
thick and triangular. ‘The innermost fibres of the outer pillar are
continued over the crest of the pubis and beneath the spermatic cord
in a thin somewhat fan-shaped layer called the triangular fascia, which,
curving upwards and inwards, passes behind the base of the inner
pillar to interlace with the fibres of the opposite side.

A portion of the aponeurosis, which is reflected backwards and out-
wards along the pectineal line from the attachment of Poupart’s liga-
ment to the spine of the pubis, constitutes a small triangular process
with a curved external border, not far distant from the femoral ring.
This receives the name of Gimbernat’s ligament. Some curved fibres,
directed across the diverging pillars and uniting them together, are
named intercolumnar. A few of these, descending upon the spermatic

INTERNAL OBLIQUE MUSCLE. 317

eord from the margin of the opening, are prolonged upon that structure
as a delicate fascia, named aéercolumnar fascia. The intercolumnar
fibres may be regarded as the lowest of a series of tendinous fibres,
which cross the aponeurosis of the external oblique muscle somewhat
obliquely over a considerable extent of its surface, and the strongest of
which proceed from near the superior spine of the ilium and upper part
of Poupart’s ligament.

Varicties—This muscle chiefly varies in respect to the number of attachments
to the ribs, the slips from the eighth and ninth ribs being occasionally double,
while those from the eleventh and twelfth are sometimes wanting. Besides the
usual slip to the pectoralis major, a slip is sometimes found to the serratus
magnus. The muscle has also been found double, the deeper portion passing
from the three lowest ribs to the crest of the lium. (Macalister.)

The obliquus abdominis internus muscle, placed under cover of
the external oblique, arises by fleshy fibres from the external half or
two-thirds of the deep surface of Poupart’s ligament, from the iliac
crest for two-thirds of its length, and by some fibres from the posterior
aponeurosis of the transversalis muscle, in the angle between the crest
of the ilium and the outer margin of the erector spine muscle. From
those attachments the fibres, spreading somewhat, pass to be inserted as
follows: the most posterior fibres pass upwards and forwards to the
lower margins of the cartilages of the last four ribs, where they are
inserted in the same plane with the internal intercostal muscles ; those
arising further forwards from the crest of the ilium pass, the upper more
obliquely, and the rest more horizontally, forwards to end in an aponeu-
rosis in front of the abdomen; those from the front part of the crest
extend horizontally inwards to the same aponeurosis ; while the fibres
from Poupart’s ligament, usually paler than the rest, arch downwards
and inwards over the spermatic cord, or the round ligament of the
uterus, and end in tendinous fibres common to them and the lower
part of the transversalis muscle, and hence known as the conjoined
tendon of these muscles ; through the medium of this tendon they are
attached to the front of the pubis, and for some distance along the
pectineal line, behind and to the outside of Gimbernat’s ligament. The
spermatic cord and round ligament pass under the arched lower border
of the internal oblique and transversalis muscles through the internal
or deep abdominal ring,

The aponeurosis of the internal oblique may be regarded as the ex-
panded tendon of the muscle continued forwards and inwards: it extends
from the margin of the thorax to the pubis, and is wider at the upper
than at the lower end. At the outer border of the rectus. muscle
this structure divides into two layers, one passing before, the other
behind, that muscle ; and the two reunite at its inner border, so as to en-
close it ina sheath. The anterior layer, as already mentioned, becomes
inseparably united with the aponeurosis of the external oblique muscle,
and the posterior layer is similarly incorporated with that of the trans-
versalis. The upper border of the posterior lamina is attached to the
margins of the seventh and eighth ribs, as well as to the ensiform
cartilage. This division, however, of the aponeurosis into layers stops
short a little above half way between the umbilicus and the pubis, the
aponeurosis below that level remaining undivided, and along with that
of the transyersalis muscle to which it is united, passing wholly in front

313 MUSCLES OF THE ABDOMEN.

of the rectus muscle. The deficiency thus resulting in the posterior
wall of the sheath of the rectus muscle is marked superiorly by a well-
defined lunated edge, whose concavity looks downwards towards the
pubis—the semilunar fold of Douglas.

Relations—The internal oblique
muscle is almost entirely covered
by the external oblique. A small
angular portion only near the place
where its posterior fibres take their
origin, under cover of the latissi-
mus dorsi, is exposed between
that muscle and the external ob-
lique, and even this is not con-
stantly found.

Fig. 224.—Lareran Virw or THE
Muscires oF THE ABDOMEN AND
TRUNK, THE INTERNAL OBLIQUE
MuschLE HAVING BEEN EXPOSED
BY THE REMOVAL OF THE EXTERNAL
OsLiguE (modified from Henle).
(AN TT)! 74

a, anterior superior spinous process
of the ilium; 6, trochanter major;
c, spine of pubes ; d, lumbar fascia;
VI to XII, the sixth to the twelfth
ribs; 1, lower part of the great pec-
toral muscle, where it is attached to
the external oblique muscle; 2, 2,
lower digitations of the serratus mag-
nus from the fourth to the eighth ribs ;
3, lower costal attachments of the
latissimus dorsi; 3’, its iliac attach-
ment; 4, trapezius ; 5, divided attach-
ments of the external oblique, left in
connection with the ribs ; 5, aponeu-
rosis of the external oblique divided in
front of the rectus, where it joins the
sheath; 6, internal oblique at its
middle ; 6’, 6’, line where it divides
to form the sheath of the rectus;
+++ XII, its attachment to the
four lowest ribs; 6”, the conjoined
tendon, and above, and to the out-
side, the internal inguinal aperture ;
7, sartorius; 8, rectus femoris; 9,
tensor vagine femoris; 10, gluteus
medius ; 11, gluteus maximus.

Varieties—A fibrous inscription
is frequently seen in the upper
part of this muscle prolonged for-
ward from the point of the tenth rib, and a slender cartilaginous slip perfectly
separate from that of the rib has been seen lying in this inscription. (Henle.)
An inscription opposite the eleventh rib is described by Macalister,

The cremaster, a muscle peculiar to the male, consists of fibres
lying in series with those of the lower border of the internal oblique
muscle. It presents an external and an internal attachment. The
external attachment is to the inner end of Poupart’s ligament, and
there its fibres are continuous with those of the internal oblique muscle ;

CREMASTER MUSCLE. 319

the internal attachment, smaller and less constant, is by means of a
tendinous band to the spine and crest of the pubis, close to the inser-
tion of the internal oblique muscle. ‘The superior fibres of the muscle

Fig. 225.—LareraL VIEW Fig, 225.
OF THE TRUNK, GIVING
A DEEP VIEW OF THE
Serratus Maanus AND
TRANSVERSALIS ABDO-
minis Muscuzs. ‘A. T.) 2

(he serratus magnus is
stretched out by the sca-
pula being drawn away
fromtheribs. «@, coracoid
process of the scapula ; 6,
glenoid cavity; c, lower
angle ; d, first dorsal ver-
tebra ; e, placed on the os
pubis, point: to the inser-
tion of Gimbernat’s liga- = === A
ment; I, VI, XII, the first, :
sixth, and twelfth ribs ;
L’, first lumbar vertebra ;
i, upper portion of the
serratus magnus attached
to the first and second
ribs ; 2, second or middle
portion attached to the
second and third ribs; 3,
lower or fan-shaped por-
tion attached to the ribs
from the fourth to the
ninth ; 4, the external in-
tercostal muscles ; 5, upper
costal origins of the trans-
versalis abdominis; 6,
origins of the muscles from
the transverse processes
of the lumbar vertebra by
the lumbar aponeurosis ;
6’, part rising from the
crest of the ilium ; 7, lower
portion rising from the
upper half of Poupart’s
ligament, and passing over
the internal inguinal aper-
ture ; 8, the sheath of the
rectus muscle opened in its
upper part by removing
the aponeurosis of the ob-
lique muscles ; 9, the same
in its lower part left entire Wie
at the place where the Ne aed
tendons pass entirely in
front of the rectus muscle ;

10, the interspinales muscles of the lumbar vertebre ; 11, gluteus minimus; 12,
pyriformis.

7) |
DY)

.

SS

a
f ROMANE
RT THT

extend between those attachments in a series of successively longer
loops, descending in front of the spermatic cord, a few of them reaching
as low as the level of the testicle: the remaining fibres, the greatest
number of which descend from the outer attachment, and a few from _
the inner, spread out inferiorly and are embedded in the substance of a

020 MUSCLES OF THE ABDOMEN.

fascia, termed cremasteric, which adheres to the fascia propria of the
testicle. Sometimes the only fibres developed are a bundle descending
from the outer attachment.

In the female there may be almost constantly detected a small bundle of fibres

descending on the round ligament of the uterus, which correspond with the last-
mentioned fibres of the cremaster muscle of the male.

The transversalis abdominis muscle, subjacent to the imternal
oblique, arises from the inner surface of the cartilages of the six lower
ribs ; from a strong aponeurosis attached to the lumbar vertebrae ; from
the inner margin of the crest of the ilium in the anterior two-thirds of
its extent, and from the iliac third of Poupart’s ligament. ‘The greater
part of the fibres have a horizontal direction, and extend forwards to a
broad aponeurosis in front ; the lowest fibres curve downwards like
those of the internal oblique, and are inserted into the front of the
pubis and into the pectineal line, through the medium of the conjoined
tendon already described as common to this muscle and the internal
oblique.

The anterior aponeurosis of the transversalis muscle commences in the
greater part of its extent at the distance of about an inch from the
outer border of the rectus muscle ; but at its upper extremity it is much
narrower, and there the muscular fibres of opposite sides approach
nearly to the middle line behind the recti muscles. It becomes united
with the posterior layer of the aponeurosis of the internal oblique
forming the posterior wall of the rectus sheath, and inferiorly, where
that aponeurosis passes entirely in front of the rectus muscle, it passes
likewise in front of that muscle.

The posterior aponeurosis of the transversalis muscle extends back-
wards between the last rib and the iliac crest, and opposite the outer
border of the erector spine muscle, becomes continuous with the lumbar
aponeurosis.

Varietics—The transversalis has been found fused with the internal oblique

(Soemmering) ; or entirely absent (Macalister). The spermatic cord has been
seen to pierce its lower border (Guthrie).

The rectus abdominis is a Jong flat muscle, consisting of vertical
fibres, situated at the fore part of the abdomen, within a tendinous
sheath, formed in the manner already described in the account of the
aponeurosis of the internal oblique muscle; it is separated from the
muscle of the other side by a narrow interval, which is occupied by a
dense fibrous structure, the /inea alba afterwards described. It arises
from the upper margin of the pubis by a flat tendon consisting of two
parts, of which the internal is much the smaller, and is connected with
the ligaments covering the pubic symphysis, while the external one is
fixed to the pubic crest. Expanding and becoming thinner at the
upper end, the muscle is inserted into the cartilages of three ribs, the
fifth, sixth, and seventh, usually by three distinct parts of unequal
size. Some fibres also are generally found attached to the ensiform
cartilage.

The fibres of the rectus muscle are interrupted by three or more
irregular tendinous intersections, named linew transverse. ‘The three
which are most constant are placed, one opposite the umbilicus, another
on a level with the ensiform cartilage, and the third intermediately
between them: and these generally run across the whole muscle.

RECTUS ABDOMINIS MUSCLE.

When one or two additional transverse lines occur, they are usual
incomplete ; one of them is very generally placed below the umbilicus,

Fig. 226.—Drrr Muscrrs
OF THE FOREPART OF
Tur TRUNK AND SHOUL-
per. (ALJ) a
For the explanation of

the references in the upper

part of the figure see p. 195.
c, ¢, cartilages of the fifth

ribs; d, ensiform portion
of the sternum; e, sym-
physis pubis; jf, anterior
superior iliac spine; 12,
insertion of the serratus
magnus on the ribs; 13, on
the right side, the rectus
abdominis ; on the left
side 13, 13’, the divided
ends of the same muscle,
a portion being removed ;
14, points to the pyrami-
dalis muscle exposed on
the left side; 15, on
the right side, the internal
oblique muscle ; 15’, origin
ot its lower fibres from the
deep surface of Poupart’s
ligament ; 15’, conjoined
tendon of the internal ob-
lique and transyersalis, de-
scending to the pectineal
line ; between 15’ and 15”,
the internal inguinal aper-
ture; 15, on the left side, cut
edge of the internal oblique,
shown diagrammatically, to
indicate the manner in
which its tendon splits to
form the sheath of the
rectus muscle; 16, the
tendon or aponeurosis of
the external oblique muscle,
uniting in front with the
sheath of the rectus.

position of the other is
variable. The inter-
sections do not usually
penetrate the whole
thickness of the mus-
cle, but are confined
chiefly to its anterior

321

ly
the

Fig. 226.
aN
CE GOSS
/ 7 le {
/ [RK
fA — SR

nf tN i
s A

EE

=

i lth

So

fibres, and are firmly united to the anterior wall of the sheath of the
muscle, while the posterior surface of the muscle has no attachment to

the sheath,

The line transverse have been regarded as indications of the abdominal ribs-

VOL.

yy

322 MUSCLES OF THE ABDOMEN.

of some of the lower animals; they are rather vestiges of the septa between the
original vertebral myotomes. They sometimes extend outwards from the rectus,
and penetrate partially into the internal oblique.

The pyramidalis is a small muscle resting on the lower part of the
rectus. It arises from the front of the pubis and the ligaments of the
symphysis, and becoming narrow as it ascends over the lower third of
the interval between the umbilicus and pubis, is inserted into the linea
alba. ;

Relations.—The pyramidalis is covered in front by the aponeurosis of the other
muscles, and rests posteriorly on the rectus, the size of the lower part of which
is augmented when the pyramidalis is wanting.

Varieties —This muscle is often absent on one or both sides : in some instances
it has been found to be double. It occasionally exceeds the length above stated.

The Zinea alba is a white fibrous structure, extended perpendicularly
downwards in the middle line from the ensiform cartilage to the pubis.
This tendinous band is formed by the union of the aponeuroses of the
two oblique and the transverse muscles, the tendinous fibres being cun-
tinued in a decussating manner from one side to the other. Some
longitudinal fibres are distinguishable towards its lower end. It is
broader superiorly than inferiorly, and a little below the middle is
widened out into a circular flat space, in the centre of which is situated
the cicatrix of the wnbilicus.

The linece semilunares are the two curved linear spaces on the surface
of the abdomen, placed externally to the outer margins of the recti
muscles. They are produced by the union of the aponeurotic tendons
of the oblique and transversalis muscles, and they correspond on their
inner side to the outer margin of the sheath of the rectus.

The quadratus lumborum is an irregularly quadrilateral muscle,
slightly broader below than above, placed between the last rib and the
crest of the ilium, close to the vertebral column. It is divisible into
two parts. One of these, arising by fleshy and tendinous fibres from the
ilio-lumbar ligament, and from the iliac crest for several inches near the
place where that ligament is attached, is inserted into the inferior
border of the last rib for about half its length, and by four tendinous
slips into the transverse processes of the four superior lumbar vertebree.
Another series of fibres, arising by two or three tendinous slips from as
many of the inferior transverse processes at their upper margins, passes
in front of those inserted into the same processes, and joins with the
part of the muscle attached to the rib.

Pelations.—This muscle is placed between the middle and deepest layer of the
lumbar aponeurosis, and its inner part is covered in front by the psoas muscle.

Varictics—The number of the points of insertion of this muscle to the ver-
tebre, and the extent of its connection with the last rib, vary in different
instances. It is sometimes attached to the body or transverse process of the last
dorsal vertebra.

ActiIons.—The abdominal muscles not only form a great part of the wall to
enclose and support the abdominal viscera, but by their contractions are capable
of acting successively on those viscera, on the thorax, and on the pelvis. When
the pelvis and thorax are fixed, the abdominal muscles constrict the cavity and
compress the viscera, particularly if the diaphragm be fixed or be made to descend
at the same time, as occurs in vomiting and in the expulsion of the foetus, the
faces, and the urine.

ACTIONS OF THE ABDOMINAL MUSCLES. 223

If the vertebral column be fixed, these muscles press up the diaphragm through
the abdominal viscera, draw down the ribs, and contract the lower border of the
thorax, and so contribute to expiration ; but if the vertebral column be not fixed,
the thorax will be bent directly forwards, when the muscles of both sides act, er
rotated to either side, should they act alternately.

Fig. 227.—DIaGRAM OF A TRANSVERSE SECTION OF THE WALL OF THE ABDOMEN, TO
SHOW THE CONNECTIONS OF THE LUMBAR AND ABDOMINAL APONEUROSIS, AND THE
SueatH oF THE Rectus Muscie. (A. T.) 4

A, at the level of the third lumbar vertebra; B, the fore part, at a few inches above
the pubes.

a, spinous process of the third lumbar vertebra ; 6, body ; 1, external oblique muscle ;
2, internal oblique ; 3, transversalis; 4, a dotted line to mark the position of the fascia
lining the abdomen ; 5, 5, in A, the anterior and posterior parts of the sheath of the
rectus, formed by the aponeurosis of the internal oblique splitting at its outer edge 2’ ;
6, the rectus abdominis ; 7, innermost layer of the aponeurosis, covering in front the
quadratus lumborum, and passin to the root of the transverse process: $, the psoas
magnus and parvus muscles; 9, the erectores spine muscles; 9+, the middle layer of
the lumbar aponenrosis passing to the extremity of the tranverse process ; 10, 10+, the
posterior layer of the lumbar aponeurosis, connected with the latissimus dorsi and serratus
inferior : in A, at the sheath of the rectus, the aponeurosis of the external oblique is
seen to unite in front with the sheath, while that of the transversalis is seen uniting
with it behind : in B, the section is taken below the semilunar fold of Douglas, where
all the tendons pass in front of the rectus as at 5’; the + near this, and in a similar
place in A, marks the middle line, and the place of the union of the several aponeuroses
in the linea alba.

If the thorax be fixed, the abdominal muscles may be made to act on the
pelvis ; thus, in the action of climbing, the trunk and arms being elevated and
fixed, the pelvis is drawn upwards, either directly or to one side, as a preparatory
step to the elevation of the lower limbs.

The attachment of the tendinous intersections of the rectus muscle to the
vy 2 ;

= =<

324 MUSCLES OF THE ABDOMEN.

anterior wall of its sheath, causes the formation of corresponding transverse
folds during its contraction, and may enable the separate parts of the muscle to
act on different portions of the abdominal wall, The pyramidalis muscle
strengthens the inferior part of the rectus.

LINING FASCIA OF THE ABDOMEN.—On the inner surface of the wall
of the abdomen is a membranous structure which lines the visceral
aspect of the deepest stratum of muscles; it is divisible into two
principal parts, the fascia transversalis and fascia iliaca.

The fascia transversalis is named from its position on the deep
surface of the transversalis muscle. It is strongest in the lower part
of the abdomen, where the muscular and tendinous support is somewhat
weaker. Followed upwards from this situation, the transversalis fascia
becomes gradually less strong, and beyond the margin of the ribs it
forms a thin cov ering for the under surface of the diaphragm. Along
the inner surface of the iliac crest, between the iliacus and tramsversalis
muscles, the fascia is attached to the periosteum. For about two inches
inwards from the anterior superior iliac spine, it is closely connected
with the posterior surface of Poupart’s ligament, and is there directly
continuous with the fascia iliac. At this place also, and to the same
extent it is attached to the fascia lata. About midway between the
iliac spine and the pubis, the external iliac artery and vein, as they pass
out into the thigh, intervene between the fascia transversalis and the
fascia iliaca, and from this point to the edge of Gimbernat’s ligament
the fascia transversalis is prolonged downwards under the crural arch,
and over the artery and vein, forming the anterior portion of the
funnel-shaped femoral sheath. As this prolongation of the fascia passes
under Poupart’s ligament, it is strengthened by a dense band of fibres
(the deep crural arch) which arches over the vessels, and is inserted
into the pubic crest and pectineal line behind the conjoined tendon
of the transversalis and internal oblique. It includes beneath it, internal
to the vessels, a space between Gimbernat’s ligament and the vein, suffi-
ciently large to admit the point of the little “finger ; ; this is called the
crural ring, and is the space through which femoral hernia descends.
About half way between the anterior superior iliac spine and the sym-
physis pubis, and about half an inch above Poupart’s ligament, the
spermatic cord in the male, or the round ligament in the female, pierces
the fascia transversalis. ‘The opening thus made is called the internal
or deep abdominal ring ; the fascia above and internal to it is thin, but
below and external to it is firm and thick, and forms a distinct crescentic
margin, over which the cord or round ligament passes ; from the borders
of the opening a delicate funnel- shaped covering , the infundibuliform
fascia, is prolonged downwards on the emerging str ucture, and forms in
cases of oblique hernia one of the coverings sof the tumour.

The fascia iliaca, stronger than the “fascia transversalis, lines the
back part of the abdominal cavity, and covers the iliacus and psoas
muscles. The densest portion of its fibres is stretched transversely from
the iliac crest, over the margin of the psoas muscle to the brim of the
pelvis, where it is intimately blended with the periosteum. Superiorly,
this membrane, becoming much weaker, is connected internally with
the sacrum, and by small and distinct processes with the intervertebral
substances and the neighbouring margins of the lumbar vertebre ; and
finally it becomes blended with the fascia which covers the diaphraem
and torms the ligamentum arcuatum externum. The external iliac

ABDOMINAL AND PERINEAL FASCLZA. 825

vessels lie in front of this part of the iliac fascia, To the outer side
of those vessels, the fascia turns forwards to be connected with Poupart’s
ligament and the fascia transversalis, as already described ; to the inner
’ side of the femoral vein it is attached to the ilio-pectineal line, along
with the fascia lata ; and between these two points, namely, behind the
femoral vessels, it continues downwards over the margin of the pelvis,
forming the back part of the sheath of those vessels.

The psoas parvus is closely connected with the iliac fascia, by means
of an expansion of its tendon.

At the back part of the abdomen there is also a thin but strong
fascia covering the quadratus lumborum muscle and forming the
anterior layer of the lumbar aponeurosis. It is attached at the
outer border of the quadratus to the middle layer of the aponeurosis,
and at its inner border to the roots of the transverse processes of the
lumbar vertebra. Superiorly it forms two strong bands, the ligamenta
arcuata of the diaphragm already described, and inferiorly it is attached
to the crest of the ilium.

The middle layer of the lumbar aponeurosis consists of strong
fibrous bundles which are attached to the posterior layer at the outer
margin of the erector spine. It intervenes between that muscle and
the quadratus, and is attached internally by three or four slips to the
tips of the lumbar transverse processes. It gives origin at its outer
part to the middle fibres of the transversalis abdominis muscle.

MUSCLES AND FASCIZ OF THE PERIN/UM AND PELVIS.

Fascia OF THE PERIN®jUM—Superficial Fascia.—In the posterior
half of the perineum the subcutaneous fat is continued deeply into the
ischio-rectal fossa, the pyramidal space intervening between the obtu-
rator fascia and the levator ani muscle. In the anterior half of the
perineum, beneath the subcutaneous fat, is placed a special layer of
fascia, continuous with the dartos, the proper superficial perineal fascia,
sometimes called fascia of Colles. 'This fascia is bound down on each
side to the margin of the pubic arch as far back as the ischial tuber-
osity ; posteriorly, along a line from the ischial tuberosity to the central
point of the perineum, it turns round the posterior margin of the
transversus perinei muscle to join the subpubic fascia, to be presently
described. From its deep surface likewise, an incomplete septum in
the middle line dips down to the urethra and passes forwards into the
scrotum. It thus happens that air blown in beneath the proper perineal
fascia on one side passes forwards and distends the scrotum to a certain
extent on that side ; it may then penetrate to the other also, and if
injected with sufficient force may reach the front of the abdomen, and
travel upwards beneath the superficial fascia; but it neither passes
backwards to the posterior half of the perineum nor down upon the
thighs. The same course is followed by urine or matter extravasated
beneath the proper perineal fascia.

The deep perineal or subpubic fascia is stretched across the
pubic arch on the deep surface of the crura of the penis and the bulb
of the urethra. It consists of two distinct layers of strong fibrous
membrane, separated by intervening structures. The anterior layer, or
triangular ligament of the urethra, attached to the inferior margin of the

326 PELVIC FASCLA.

symphysis pubis and to the rami of the pubic and ischial bones, and
extending in the middle line back to the central point of the perineum,
is perforated about an inch from the symphysis by the urethra, imme-
diately before its expansion into the bulb, and above and in front of
this by the dorsal vein of the penis in the middle line, and by the pudic
arteries and nerves on each side. At its posterior and inferior extremity
it is connected with the deep layer, and with the recurved margin of
the perineal fascia. Between the two layers of the subpubic fascia are
placed the membranous portion of the urethra, the deep transverse and
constrictor muscles of the urethra, and Cowper’s glands, together with
the pudic arteries and nerves and the arteries of the bulb. The posterior
or deep layer consists of a right and left lateral half, which are separated
in the middle line by the urethra close to the neck of the prostate, and
are continued into the capsule of that gland. This layer of fascia is
superficial to the anterior fibres of the levator ani muscle, which he
between it and the pelvic fascia, and is connected with a thin web of
areolar tissue which extends backwards on the surface of the levator ani
muscle, and is distinguished as the anal fascia.

In the female the subpubic fascia is divided in the middle by the
vagina.

Fasctm oF THE Prenvis.—The fascia lining the pelvis is described
in three parts, viz., the upper part, or undivided pelvic fascia, and
the two lower—the recto-vesical fascia, and the obturator fascia. The
first of these is divided into the other two at the level of a white
band of fibres, stretched from the lower part of the symphysis pubis to
the spine of the ischium. The space between those two fascice is
occupied by the levator ani and the fat and other contents of the ischio-
rectal fossa.

a. The pelvic fascia is attached at the side superiorly for a short
space to the brim of the pelvis, but in front of the line of its osseous
attachment it inclines downwards towards the lower part of the sym-
physis pubis, following the margin of the obturator internus muscle.
Anterior to the spine of the ischium, it lies between the obturator
internus and the peritoneum, and at the back part of the pelvis is con-
tinued as a thin membrane over the pyriformis muscle and the sacral
nerves, and is perforated by branches of the internal iliac artery and
vein.

b. The recte-vesical fascia is the direct continuation of the pelvic
fascia downwards and inwards to the viscera, below the level of the
white line previously mentioned ; rt descends, immediately in contact
with the inner surface of the levator ani muscle, to the prostate gland,
the urinary bladder, and the rectum. On reaching those organs it
spreads over them, and to some extent encases them. Close to the
symphysis pubis, a short band is directed backwards above the prostate
gland, to the bladder, with which it is intimately connected. A similar
band exists at the opposite side of the symphysis pubis, and the two
are separated by a narrow depression, in which the dorsal veins of the
penis lie, after entering the pelvis. The bands in question are named
the anterior true ligaments of the urinary bladder. At the place where
it is reflected inwards to the side of the bladder, the recto-vesical
fascia forms the lateraltrue vesical ligament. At the side of the bladder
and prostate, the fascia gives a prolongation forwards on the veins
which cover the prostate, and is firmly adherent to the capsule of

OBTURATOR FASCIA. PERINEAL MUSCLES, 32g

that organ, except at its base, where an angular furrow, occupied by
large veins, exists between the prostate and bladder. Into this furrow
the incision for lithotomy ought not to extend, on account of the danger
from wounding the veins and from the infiltration of urine. A portion
of the recto-vesical fascia invests the vesicule seminales, and is extended
across between the bladder and the rectum ; continuing into the mem-
brane of the opposide side, it supports the bladder, and separates that
organ from the intestine. On the rectum the fascia is also reflected
upwards and downwards, gradually degenerating into a thin membrane
over the surface of the bowel, as it likewise does on the bladder.

c. The obturator fascia is a membrane stretched over the lower part
of the surface of the obturator internus muscle within the pelvis. It is
connected superiorly with the white band before referred to, which con-
sists indeed of its superior fibres, and it is attached in the rest of its
circumference to the rami of the pubis and ischium, the ischial tuber-
osity, and the greater or lesser sacro-sciatic ligaments. It lines the
inner surface of the obturator internus muscle and presents between its
fibres a canal, which contains the internal pubic artery and nerve in
their course to the perineum.

The obturator fascia is sometimes included in the description of the pelvic
fascia, while the recto-vesical is considered as an offset from it. It will be found,
however, on dissection, that the recto-vesical fascia is always most directly con-
tinuous with the pelvic fascia, and that the obturator fascia is only loosely con-
nected with it. Indeed, the fibres of the levator ani muscle in most cases pass
upwards to some extent beyond the white line, and thus separate the obturator
trom the pelvic fascia.

The dschio-rectal fossa is a pyramidal space occupied by subcutaneous
fat. It is bounded externally by the obturator fascia, posteriorly by
the gluteus maximus muscle and great sacro-sciatic ligament, and
internally by the recto-vesical fascia ; anteriorly, its base is limited by
the margins of the perineal and the subpubic fasciee.

In the female, the pelvic fascia is connected with the vagina in the
same manner as with the other pelvic organs.

Muscies.—The muscles of the perinzeum differ somewhat in the two
sexes, and must therefore be separately described in each. In both
sexes they may be divided into two groups, according as they are more
immediately connected with the lower orifice of the alimentary canal or
with the genito-urinary outlet. In both groups superficial and deep
muscles are to be distinguished.

A.—In THE MAuE.—a. Anat, Muscies.—The internal or circular
sphincter is a thick ring of unstriped muscle connected with the lowest
circular fibres of the rectum, which will fall more naturally to be
described along with the anatomy of that organ.

The superficial or external sphincter muscle is a thin layer of
fibres placed immediately beneath the skin surrounding the margin of
the anus. It is elliptical in form, about half an inch in breadth on each
side of the anus, and is attached posteriorly by a small tendon to the
tip and back of the cocsyx ; passing forwards on each side of the anus,
it becomes blended anteriorly with the transverse and the bulbo-caver-
nosus muscles at the central point of the perineum, a name given to the
depressed root situated in the male between the anus and the bulb of
the urethra, and in the female between the anus and vulva. =

328 MUSCLES OF THE PERINEUM.

The levator ani arises in front from the posterior surface of the
pubis, near the symphysis and midway between its upper and lower

Fig. 228. —SvperricraL VIEW oF
THE MuscLEs oF THE PERINEUM
IN THE Mate (modified from
Bourgery). (A. 7.) 2

a, crest of the pubis; 6, coccyx ;
c, placed on the tuberosity of the
ischium, points by the line to the
greater sacro-sciatic ligament; x,
the anus; 1, placed on the spongy
body of the urethra in front of the
bulbo-cavernosus muscles; 2, the
central point of the perineum; 3,
ischio-cavernosus ; 4, transversus
perinzi ; 5, levator ani; from 2 tob,
elliptical sphincter of the anus ; sur-
rounding x, is the circular sphincter ;
6, coccygeus muscle; 7, adductor
longus; 8, gracilis; 9, adductor
magnus; 10, semitendinosus and
biceps; 11, on the left side, the
gluteus maximus entire; 11’, the
same cut on the right side, so as to
expose a part of the coccygeus muscle.

borders ; behind from the spine of the ischium, and between those
points from the pelvic fascia along the line of attachment of the obturator
fascia. Some of its fibres are also traceable upwards in the substance
of the pelvic fascia above the level of the obturator. J'rom this exten-
sive origin the fibres of the levator proceed downwards and inwards
towards the middle line of the floor of the pelvis. Its posterior fasciculi
are inserted upon the side of the lower end of the coccyx ; the bundles
immediately in front of the coccyx unite in a median raphé with those
of the opposite sides as far forward as the margin of the anus ; the
middle and larger portion of the muscle is prolonged upon the lower
part of the rectum, where it is connected with the fibres of the external
sphincter, and slightly with those of the internal; and lastly, the
anterior muscular bundles pass between the rectum and the genito-
urinary passages, and, descending upon the side of the prostate, unite
beneath the neck of the bladder, the prostate, and the neighbouring part
of the urethra, with corresponding fibres from the muscle of the oppo-
site side, and blend also with those of the external sphincter and deep
transverse perineal muscles.

The anterior portion of the levator ani, which arises from the ramus
of the pubis, close to the symphysis and above the pubic arch, and also
from the adjacent fascie, is sometimes separated at its origin by areolar
tissue from the rest of the muscle. From this circumstance, and from
its connection with the prostate gland, it was described by Santorini,
and since by Albinus and Scemmerring, as a distinct muscle, under the

name of the levator prostate. Its fibres pass backwards parallel with
the middle line.

ftelations.—The upper or pelvic surface of the levator ani is in contact with
the recto-vesical fascia, the capsule of the prostate, and the lower end of the

PERINEAL MUSCLES IN THE MALE. 529

rectum. The under or perineal surface, invested by the thin anal fascia, is
covered by the fat which occupies the ischio-rectal fossa. The posterior border is
continuous with the coccygeus.

Fig. 229.—Lerr wALr or THE MALE
PELvis, To sHow THE Leyator ANI AND
Coccyceus Musctss (after Cloquet). 4
a, the promontory of the sacrum; 8,

the crest of the pubis; c, the last bone of
the cocecyx ; d, the spine of the ischium ;
e, the symphysis pubis ; f, a small portion
of the anal part of the rectum; g, half
the prostate gland; h, half the bulb and
a portion of the penis; 1, upper part
of the obturator internus muscle exposed
by removing from within it the pelvic
fascia ; 2, coccygeus muscle, and above it
and between it and d, the sacro-sciatic
ligaments ; 8, inner surface of the levator
ani; the white line extending between d
and e, shows the place of its origin from
the fascia of the pelvis ; below is shown
the descent of the fibres to the anus, and
to the portions of the perinzeum before and
behind it.

The coccygeus or levator Carer aeaticele is composed of fleshy
and tendinous fibres, forming a thir, flat, and triangular sheet, which
arises by its apex from the spine of the ischium and the lesser sciatic
ligament, and is attached along its base to the border of the coccyx and
the lower part of the sacrum. The fibres of this muscle diverge as they
approach the middle line, while those of the levator ani rather converge
as they descend.

Relations.—The internal or pelvic surface of this muscle assists in supporting
the rectum : its external or under surface rests on the front of the sacro-sciatic
ligaments, and on the gluteus maximus muscle.

The levatores ani and coccygei muscles together have been named somewhat
appropriately by Meyer, the pelvic diaphragm.

Varieties—The coccygeus is sometimes inserted into the side of the sacrum
instead of the coccyx. A few muscular fibres have been found extending from
the lower part of the sacrum to the coccyx, both in front and behind. The
anterior slip is decribed by Von Behr and others as cwrvator, and the posterior as
extensor coccygis. (See Macalister, Musc. Anomalies, p. 66.)

b. GENITO-URINARY MusciEs.—Covered by the special fascia of the
perineeum are three muscles, placed superficially —the superficial trans-
verse, the ischio-cavernosus, and the bulbo-cavernosus ; while, situated
more deeply between the superficial and deep layers of the subpubic
fascia, are the deep transverse muscle and the constrictor of the urethra.
sometimes described as one muscle under the name of compressor of
the urethra.

The transversus perinei muscle arises from the inner surface of
the pubic arch, near the ischial tuberosity, and is directed obliquely
forwards and inwards to unite with the muscle of the opposite side, as
well as with the sphincter ani and bulbo-cavernosus at the central point
of the perineum. It lies immediately in front of the line where the
perineal dips back to join the subpubic fascia. i

330 MUSCLES OF THE PERINEUM.

Varietics.—It is sometimes absent, and at other times one or more smal
muscular slips are found lying on the same plane with it, in front or behind.

The ischio-cavernosus, or erector penis muscle, embracing the crus
penis, arises from the inner part of the tuber ischii, behind the ex-
tremity of the crus penis, and from the pubic arch along the inner and
outer sides of the crus. From this origin the fleshy fibres are directed
forwards to a tendinous expansion which is spread over the lower surface
of the crus penis, and is inserted into the under and outer surfaces of
that body towards the fore part.

Varictics—Houston has described (Dublin Hosp., Reports, vol. v.), under the
name of compressores vene dorsalis penis, two slips of muscle, separated from the
erectores penis on each side by an interval, though apparently belonging to them.
They are said to arise from the pubic arch, above the origin of the erector
muscles and the crura of the penis, and, passing upwards and forwards, are
inserted above the dorsal vein, by joining each other in the middle Jine. These
muscles, which are well developed in the dog and several other animals, are by
no means constant in the human subject.

The bulbo-cavernosus or ejaculator urine, may be considered as
a single muscle, consisting of two symmetrical parts.

The fleshy fibres of the muscle take origin behind from the central
tendon of the perineum, and from a median tendinous raphé interposed
between the two halves of the muscle. The larger number of the fibres
are directed round the bulb and the adjoining part of the corpus
spongiosum urethra, and join above that body with those from the
opposite side by a strong aponeurosis. At the fore part, a portion of
the muscle passes over the sides of the corpus cavernosum, and is
attached to that body in front of the erector penis: from its insertion
a tendinous offset is said to be prolonged over the dorsal vessels of the
penis (Kobelt). The posterior fibres, shorter than the anterior, are
inserted into the front of the triangular ligament.

The fibres which invest the most prominent part of the bulb are more or less
distinct from those contiguous to them, and have been described by Kobelt as
forming a separate muscle, to which he has given the name compressor hemis-
pheriim bulbi. The fibres of this muscular slip are connected by a small tendon,
above the urethra, with the corresponding part of the opposite side.

The deep transversus perinzi muscle is a thin rather inconstant
fasciculus which, arising from the margin of the pubic arch, is directed
inwards and meets with its fellow of the opposite side behind the bulb, at
the central point of the perineum. Its fibres conceal Cowper's gland.

The constrictor urethre muscle consists of a number of transverse
fibres extending across the arch of the pubis, some of them above and
others below the membranous portion of the urethra, and closely
embracing it. In some bodies a tendinous raphé, placed over the
middle of the urinary canal, separates each stratum into lateral halves.

Relations—This muscle rests in contact with the deep layer of the triangular
ligament, which separates it from the anterior fibres of the levator ani,

Circular fibres of Santorini (stratum internum circulare, Miiller).—
Beneath the transverse muscle just described is a series of circular in-
voluntary muscular fibres, entirely surrounding the membranous part

PERINEAL MUSCLES IN THE FEMALE. 33%

of the urethra: these are continuous behind with the circular fibres of
the prostate, and are referred to in the description of that body. (See
Structure of the Prostate.)

Tig. 230. —Posrrrror View or THE Peses Fig. 230.

WITH PART OF THE BiappeR AND

Urerura Arracuen (from Santorini). $ t

1, body; 2, rami of the pubes; 3,
obturator internus muscle ; 5, portion of
the fundus and neck of the bladder Jaid
open; 6, the prostate gland; 7, trans-
verse fibres of the compressor urethra
muscle, passing above the urethra; 8,
similar fibres passing beneath that canal.

Varicties—A pubo-urethral muscle
was described by James Wilson (Medico-
Chirurgical Trans., London, vol. i. p.
176), and is sometimes referred to as
Wilson’s muscle, but has not been re-
cognised as a separate muscle by suc-
ceeding anatomists. An unstriped
pubo-vesical band has been described,
descending from the back of the
symphysis to the neck of the bladder
(Luschka).

Nerves.—The muscles of the urethra and penis are supplied by the inferior
hemorrhoidal branch of the pudic nerve; the levator and sphincter ani by the
inferior hemorrhoidal and by the fourth and fifth sacral and by the coceygeal
nerves ; and the coccygeus muscle by the three last-named nerves.

Actions.—The sphincters of the anus cause by their contraction occlusion of
that aperture. The contraction of the external is usually maintained invqlun-
tarily, though it may be rendered firmer by an act of the will; that of the
internal is wholly involuntary.

he Jevator ani and coceygeus elevate the lower part of the rectum and inyert
its anal border, after the protrusion and eversion which accompany defecation.

he transvcrsi acting together draw backwards and fix the central point of the
perineum, thus assisting to give a base of support to the ejaculator muscle.

The erector penis serves to compress the crus penis and thus assist in producing
or at least in maintaining the erection of the penis.

The cjaculator urine compresses the bulb and the adjoining part of the corpus
spongiosum of the urethra, so as to eject forcibly any fluid lodged in the canal.
It comes into action near the end of the process of micturition, when its con-
traction is mainly a voluntary act, and in the emission of the semen when it is
involuntary.

The constrictor urcthre and the circular involuntary muscles diminish the
calibre of the urethra and expel its contents ; their fibres contract near the end
of micturition, so as to assist the ejaculator in clearing the canal.

B.—In THE FEMALE. —In the female the anterior fibres of the
levator ani embrace the vagina as they do the prostate in the male.

The transversus perinei and the sphincter ani are arranged
nearly in the same manner as in the male.

The erector clitoridis differs from the erector penis of the male by
its smaller size alone.

The sphincter vagine is attached behind to the central point of
the perineum, in common with the sphincter ani and transversus perinet
muscles ; its fibres open out to surround the vaginal orifice and vesti-
bule, closely embracing on the outer side the two bulbs of the vesti-

332 MUSCLES OF THE PERINEUM.

bule; again approaching each other in front, they become narrow, and

Fig. 231. Fig. 231.—MusciEs oF THE PERINEUM IN
tHE Frmaue. (A. T.) 4}

a, clitoris ; b, crus clitoridis ; ¢, is placed
in the vestibule above the orifice of the
urethra ; d, vagina; X, anus; e, coccyx ;
1, external sphincter ani muscle; 2,
sphincter vagine ; 2’, a few of its fibres
prolonged to the clitoris; 3, levator ani;
4, on the left ischial tuberosity, points to
the transversus perini (the inner fibres of
this muscle are represented too far forwards
in the figure) ; 5, 6, ischio-cavernosus ; 7,
gracilis; 8, adductor magnus and semi-
tendinosus, &c. ; 9, gluteus maximus.

are inserted upon the corpora caver-
nosa of the clitoris, a fasciculus
crossing over these and including
the vena dorsalis. The two halves
of this elliptical muscle appear to
correspond strictly to those of the buibo-cavernosus muscle in the male.

A deep transverse muscle, corresponding to part of the constrictor
urethree of the male, has been described as resting on the pubic surface
of the female urethra.

THE MORPHOLOGY OF THE FASCIA AND MUSCLES OF THE
TRUNK AND HEAD.

Fasciee.—There is a general correspondence in the relation of the deep fascia
to the skeleton and masses of the trunk muscles throughout vertebrate animals,
In its simplest and lowest form the general investing fascia is prolonged from
the surface towards the skeleton in four places, viz., two median, which have
been called respectively the newral and hemal septa, and two lateral, one on
each side, running towards the transverse processes of the vertebra. The layers
of the hemal septum are in close contact in the caudal region, but they are
separated and somewhat complicated in the rest of the trunk by the interpo-
sition of the visceral cavity between them.

In man and the higher animals the dorsal part of the general investing fascia
is represented by the tendinous attachments of the trapezius, latissimus dorsi,
and serrati postici muscles, and by the vertebral aponeurosis and deep temporal
fascia, while the deep fascia of the side and front of the trunk, neck, and
head and the aponeurotic sheath of the limbs correspond with its ventral portion.
The neural septum remains as the median fascial interval of the dorsal spinal
muscles, ligamentum nuche, &0. The hzemal septum partly constitutes the linea
alba, and is elsewhere separated into two as an investment of the visceral cavity,
forming the transversalis, iliac, and pelvic fascie, The lateral septum, which is
strongly developed in fishes and amphibia, is only seen at all clearly in the
middle layer of the lumbar aponeurosis of man and the higher animals, being
in them situated much nearer the dorsal than the ventral aspect of the body.
This difference of position is coincident with the greater development of the
ventro-lateral muscles and the limbs in the higher than in the lower vertebrates.

Muscles.—The dorso-lateral muscle consists of fibres which more than any
others retain their original segmented character and longitudinal direction. It
is represented in man by the mass of muscles, the chief of which is the erector
spine, which lies in the vertebral groove of the back, and which, arising from the
lower vertebra, splits up as it passes forwards to be inserted into other vertebra,
the ribs and the skull. It may be divided into three sets of muscles, characterized
by the ditterent direction of their fibres. The “ist set consist of those which run

MORPHOLOGY OF THE TRUNK-MUSCLES. 338

for the most part in a longitudinal direction, as from spine to spine, in spinalis
and interspinales ; from transverse process to transverse process in longissimus
dorsi and intertransversales ; or from rib to rib in ilio-costalis. The second set
consist of muscular fibres directed more or less obliquely upwards and outwards
from spines to transverse processes, as in splenius capitis and colli, rectus posticus
major and obliquus inferior. The third set are also oblique, but they are directed
upwards and inwards from transverse processes to spine, as in complexus, semi-
spinalis, multifidus, and obliquus superior; and from transverse processes to
lamin, as in rotatores costarum.

In the posterior part of the trunk in tailed animals this dorsal series of muscles
is continued backwards without interruption as the superior caudal muscles, and
in man an occasional muscle is sometimes found developed as an extensor coc-
cygis ; but as a general rule owing to the very slight development of the caudal
vertebree, and the large size of the pelvic girdle, the dorso-lateral muscles do
not in man extend beyond the upper part of the sacrum.

Anteriorly this muscle is prolonged to the side of the head, where it forms
‘the group of temporal, pterygoids, masseter, and probably the orbital muscles,
The connection between these muscles and the dorsal muscles is well seen in the
Tailed-Batrachians, where the fibres of the dorsal muscle are directly continuous
with those of the temporal. In man this continuity is interrupted by the ossifi-
cation of the temporal ridge and root of the zygoma.

The ventro-lateral muscle, while equally simple in the lowest vertebrates with
the dorso-lateral, presents in the higher animals much greater complexity both of
form and attachments. As regards its general relation to the vertebral axis of
the body it may be divided into two portions, which are usually quite distinct
from each other.

The first or deeper portion is that to which the name of Aypawial may most
properly be applied. It consists of fibres which lie for the most part immediately
under the bodies of the vertebrze and attached to them. ‘They may also
spread round the internal surface of the walls of the visceral cavity of the
body, and may even, as in the diaphragm and levator ani, spread across that
cavity, forming one or more muscular partitions. Posteriorly this set of muscles
is prolonged on the under surface of the tail, as the most deeply situated layer,
corresponding to an occasional muscle in man, the curvator coccygis. In man,
also, two prolongations are sent outwards on the hind limb, one on its preaxial
border, the psoas, the other on its postaxial, the pyriformis. Passing forwards, we
find belonging to the same group, the subvertebral muscles, represented in man by
the subcostals, but which in birds, serpents, &c., are very largely developed as
the retrahentes costarum and the levatores costarum interni; also the various
diaphragms, including the post-cardiac or midriff, and the pelvic or levator ani.
In this list, also, should be placed the triangularis sterni, or, as it is called by
some, the subcostalis anterior.

In front of the thorax these hypaxial muscles are prolonged in two sub-divi-
sions, of which the upper forms the recti antici and longus colli, and the lower
includes the muscles which connect together the various parts of the hyo-
branchial arches and jaws, and invest the buccal and pharyngeal cavities ; the
chief of these being the hyoid and styloid muscles, the digastric, or at least its
posterior belly, the lingual muscles, the buccinator and palatal muscles, and the
constrictors of the pharynx.

The second or more superficial portion of the ventro-lateral muscle may be dis-
tinguished as paravial (Mivart). It arises in connection with the transverse
processes of the vertebra, from their lower surfaces and tips and from the lateral
septa and general fascial investment. It thus at its place of attachment to the
vertebral axis separates the epaxial from the hypaxial sets of muscles. It is
further distinguished by the disposition which certain of its sclerotomes show to
ossification in the ribs and the limb-girdles. These paraxial muscular bundles
form the superficial layer of muscles on the ventral surface of the tails of fishes,
&e., and almost the entire thickness of the muscular layer which bounds the
visceral cavity of all vertebrates. Their connection with the alimentary canal is
limited to its extremities where they form the external sphincters,

334 MORPHOLOGY OF THE TRUNK-MUSCLES,

According to the direction of its fibres the trunk portion of this muscular mass
may be divided into two groups of muscles, a ventral with longitudinally directed
fibres and a lateral with more or less obliquely directed fibres.

The ventral group is represented in man by the rectus abdominis, rectus
thoracis (an occasional muscle), and the sterno-mastoid, and repeats more closely
the simple segmented condition of the dorsal muscle than is the case with the
lateral fibres. In fishes the oblique fibres are almost entirely wanting, and in
the lower vertebrates generally they are less developed than the longitudinal.
On the other hand in the higher forms, as in man, the oblique fibres are the
more important, the longitudinal fibres being in certain places (thorax)
absent altogether, or only occasionally present as rectus thoracis. Again, the
connection of the rectus thoracis with the sterno-mastoid is but rarely seen in
man. In some animals, as Lepidosiren, the oblique fibres are directly continuous
with the longitudinal, but in man greater differentiation exists, for the lateral
muscles are merely prolonged forwards as strong aponeuroses which form a
fibrous sheath for the rectus on each side of the middle line. In man these
fongitudinal fibres have little or no connection with the muscles of the limbs, but
in Urodelans they are continued outwards upon the ventral aspect of each limb
as part of the pectoralis major and gracilis.

Longitudinal fibres are also found in the pyramidalis, a small rudimentary
muscle in man, but which in marsupials and monotremes is extremely large ;
they are also found, but rarely, in man between the lateral oblique muscles
forming a lateral rectus, which consists of afew fibres running between the lower
yibs and the ilium. Posteriorly again the longitudinal direction is maintained
by certain fibres of the quadratus lumborum.

The Jatcral group of trunk muscles, distinguished by the oblique direction of
their fibres, is divisible usually into three or it may be into four layers. In the
lowest vertebrates this stratification does not occur, but in the higher animals it
is coincident with the differentiation of separate muscles. Of these layers three
are very constant in their relations and extent, but the fourth, which is the
most superficial, though very constantly found, is on the whole only a partial
layer. In man these layers are represented, the first three by the abdominal
muscles, the external and internal oblique and transversalis respectively, and the
fourth by the platysma myoides, the facial, auricular and epicranial muscles.

The transverse or deepest of these layers is represented by the transversalis
muscle, and according to Humphry and others by the triangularis sterni and the
subcostals, which. however, have already been described as belonging more pro-
perly to the hypaxial set of muscles.

The internal oblique is in series with the internal intercostals. levatores costa-
rum, anterior cervical and lateral lumbar intertransversales, and scaleni muscles.
it is also in most direct connection with the quadratus lumborum. Posteriorly
this layer furnishes the ischio-caudal (occasionally found in man), the erector
penis. compressor urethra, and transversus perinei. Laterally it gives the costo-
scupular muscles, serratus magnus and levator scapule, and the costo-coracoid,
or subclavius, to the shoulder girdle.

The external oblique layer is prolonged upwards upon the side of the chest, and
outwards upon the fore limb as pectorales major and minor, latissimus dorsi, and
between the limb and the head, as cleido-mastoid and trapezius.

The fourth layer, corresponding to the panniculus carnosus of animals, seems
to be mainly developed from the cutaneous surface of the last or external oblique
{ayer ; it is also developed in close connection with the skin and fascial invest-
ment. In man this layer extends only upon the surface of the head and neck,
and very slightly over the shoulder. It forms the subcutaneus colli or platysma
myoides, and those slight continuations downwards which are found upon the
surface of the pectoral and deltoid muscles. On the surface of the head this
forms the epicranial muscles, with the intervening aponeurosis, the auricular
und the facial muscles, except the orbicularis palpebrarum. All these muscles
are attached to bone usually by one end only, the other being attached to the
skin or to the cartilage of some moveable structure, but in some cases they may
reach to the deeper structures by both ends. Portions of this layer in animals

ANATOMY OF INGUINAL HERNIA. BED)
may blend with or even take the place of parts of the subjacent muscles, or they
may be enormously developed as compared with the other layers, or lastly, the
whole layer may be aborted. (See the works of Humphry and Mivart, as quoted
at p. 185.)

THE SURGICAL ANATOMY OF HERNIA.

In connection with the description of the fasciee and muscles forming
the walls of the abdomen, it is desirable to introduce a short account
of the anatomical relations of the various kinds of abdominal hernie.
These hernial protrusions are chiefly of three kinds, inguinal, femoral,
and umbilical. The last-named, however, which occurs at the umbilicus,
inasmuch as it presents relations by no means intricate, need not be
more than mentioned in an anatomical work. An inguinal hernia
following the course of the spermatic cord from the cavity of the abdo-
men, and a femoral hernia coming through the crural canal at the inner
side of the femoral vessels, have important anatomical relations which
must be studied with the greatest attention.

INGUINAL HERNIA.

The inguinal canal, throngh which the spermatic cord passes from
the cavity of the abdomen to the testis, and through which an inguinal
hernia also passes, begins at the internal abdominal ring, and ends at
the external one. It is oblique in its direction, being parallel with and
immediately above the inner half of Poupart’s ligament; and it measures
two inches in length. The external ring is immediately over the crest
of the pubis, and the internal is opposite the middle of Poupart’s liga-
ment. In front the canal is bounded by the aponeurosis of the external
oblique muscle in its whole length, and at the outer end by the fleshy
part of the internal oblique also ; behind it, is the fascia transversalis,

Fig, 232.—Tur APponEUROSIS OF THE
ExrernaL Opriigure MusciE anp
THE Fasora Lara.

1, the internal pillar of the ab-
dominal ring ; 2, the external pillar
of the same (Poupart’s ligament) ; 8,
transverse fibres of the aponeurosis ;
4, pubic part of the fascia lata ; 5, the
spermatic cord ; 6, the long saphenous
vein; 7, outer part of the fascia
lata.

together with, towards the
inner end, the conjoined ten-
don of the two deeper abdomi-
nal muscles. Above, the canal
is bounded by the arching
lower borders of the internal
oblique and transversalis mus-
cles, while below, it is sup-
ported by the broad surface
of Poupart’s ligament, which
separates it from the sheath
of the large blood-vessels de-
scending to the thigh, and from the femoral canal at the inner side of

336 SURGICAL ANATOMY OF HERNIA.

those vessels. The deep epigastric artery is close to the inner korder
of the internal ring, and the femoral vessels are beneath it, and rather
to its inner side.

Fig. 233.—Drrprr Dissection or THE ABDOMINAL WALL IN THE GROIN.

The aponcurosis of the external oblique muscle having been divided and turned down,
the internal oblique is brought into view with the spermatic cord escaping beneath its
lower edge ; 1, aponeurosis of the external oblique ; 1’, lower part of the same turned
down ; 2, internal oblique muscle ; 3, spermatic cord; 4, saphenous vein.

The spermatic cord, which occupies the inguinal canal, is composed
of the arteries, veins, lymphatics, nerves, and excretory duct (vas
deferens) of the testis, together with a quantity of loose areolar tissue
mixed up with those parts.

The coverings given from the constituent parts of the abdominal
wall to the spermatic cord, besides the integuments, are, from the
external ring a prolongation of the intercolumnar or spermatic fascia ;
the cremasteric muscle and fascia from the lower border of the internal
oblique muscle, and a thin, funnel-shaped prolongation of the trans-
versalis fascia from the edge of the inner ring (infundibuliform fascia).
Lastly, on the inside of the abdominal walls is the peritoneum, and a thin
layer of areolar tissue lying between the peritoneum and fascia transver-
salis, and usually containing a smali quantity of sub-peritoneal fat.

VARIETIES OF INGUINAL HERNL®.—Two principal forms of inguinal
hernia are described which are distinguished according to the part of
the canal in which they first enter, as well as by the position which
they bear with respect to the epigastric artery. ‘Thus, when the hernia
takes the course of the inguinal canal from its commencement, it is
named oblique, because of the direction of the canal, or external, from
the position which its neck bears with respect to the epigastric artery.
On the other hand, when the protruded part, without following the

OBLIQUE INGUINAL HERNIA. 387

Fig. 234.—Tur Incuinan Canan AND FemoRAL SHEATH FULLY EXPOSED.

The lower part of the external oblique has been removed (with the exception of
Poupart’s ligament), a portion of the internal oblique raised, and the transversalis
muscle and fascia brought into view. The femoral artery and vein are seen to a small
extent, the fascia lata having been turned aside and the sheath of blood-vessels laid
open. 1, external oblique muscle ; 2, internal oblique; 2’, part of same turned up ;
3, transyersalis muscle. Upon the last-named muscle is seen a branch of the circumflex
iliac artery, with its companion veins ; 4, transversalis fascia ; 5, spermatic cord covered
with the infundibuliform fascia. 6, upper angle of the iliac part of fascia lata ; 7, the
sheath of the femoral vessels ; 8, femoral artery ; 9, femoral vein ; 10, saphenous vein ;
11, a vein joining it.

length of the canal, passes at once through its posterior wall at a point
opposite the external abdominal ring, the hernia is named, from its
course, direct, or, from its relation to the epigastric artery, internal.

Oblique inguinal hernia.—In the common form of this hernia the
protruded viscus carries before it a covering of peritoneum (the sac of
the hernia), derived from the outer fossa of that serous membrane ;
and, in passing along the inguinal canal to the scrotum, it is succes-
sively clothed with the coverings given to the spermatic cord from the
abdominal parietes. The hernia and its sac lie directly in front of the
vessels of the spermatic cord, and do not extend below the testis, even
when the disease is of long standing.

When the hernia does not extend beyond the inguinal canal, it is distinguished
by the name dubonocele : and when it reaches the scrotum, it is commonly named
from that circumstance scrotal hernia.

There are two other varieties of oblique inguinal hernia, in which the
peculiarity depends on the condition of the process of peritoneum that accom-
panies the testis when this organ is moved from the abdomen. In ordinary
circumstances the part of the peritoneum connected immediately with the
testis, becomes separated after birth from the general cavity of that serous

VOL. I. Z

338 SURGICAL ANATOMY OF HERNLZ,

membrane by the obliteration of the intervening canal; and the hernial pro-
trusion occurring after such obliteration has been completed, carries with it a
distinct serous investment—the sac. But if this process of obliteration should
not take place, and if a hernia should be formed, the protruded part is then
received into the cavity of the tunica vaginalis testis, which serves in the place
of its sac. In this case the hernia is named congenital (hernia tunice vaginalis,
—Cooper). It is thus designated, because the condition necessary for its for-
mation only exists normally about the time of birth; but the same kind of

Fig. 285.—DIAGRAM OF A PART OF THE
PERITONEUM AND THE TuNICA VAGINA-
tis TESTIS.

In the first, A, the serous investment of
the testis is seen to be continuous with
the peritoneum ; while in the second, B,
the two membranes are shown distinct from
each other. 1, the peritoneal cavity ; 2,
the testis.

hernia is occasionally found to be
first formed in the adult, obviously in
consequence of the tunica vaginalis re-
maining unclosed, and still continuous
with the peritoneum. The congenital hernia, should it reach the scrotum,
passes below the testis; and, this organ being embedded in the protruded
viscus, a careful examination is necessary in order to detect its position, This
peculiarity serves to distinguish the congenital from the ordinary form of the
disease.

To the second variety of inguinal hernia, in which the distinguishing character
depends on the state of the tunica vaginalis testis, the name infantile has been
applied (Hey). The hernia in this case is covered with a distinct sac, which is
again invested by the upper end of the tunica vaginalis. The relative position
of the two serous membranes (the hernial sac and the tunica vaginalis) may be
accounted for by supposing the hernia to descend when the process of the perito-
neum, which accompanies the testis from the abdomen, has been merely closed
at the upper end, but not obliterated for any length. Hence during an operation
in such a case, the hernial sac is met with only after another serous bag (the
tunica vaginalis testis) has been divided. The peculiarity here described has
been repeatedly found present in the recently formed herniz of grown persons.
The term infantile, therefore, like congenital, has reference to the condition
of certain parts, rather than to the period of life at which the disease is first
formed.

In the female, oblique inguinal hernia follows the course of the round
ligament of the uterus along the inguinal canal, in the same manner as
in the male it follows the spermatic cord. After escaping from the
external abdominal ring, the hernia lodges in the labium pudendi.
The coverings are the same as those in the male body, with the
exception of the cremaster, which does not exist in the female: but it
occasionally happens that some fibres of the internal oblique muscle
are drawn down over this hernia in loops, so as to have the appearance
of a cremaster (Cloquet).

A strictly congenital inguinal hernia may occur in the female, the protruded
parts being received into the little diverticulum of the peritoneum (canal of
Nuck), which sometimes extends into the inguinal canal with the round ligament.
But as this process of the peritoneum, in such circumstances, would probably not
differ in any respect from the ordinary sac, there are no means of distinguishing
a congenital hernia in the female body.

Direct inguinal hernia (internal: ventro-inguinal).—Instead of

DIRECT INGUINAL HERNIA. 339

following the whole course of the inguinal canal, in the manner of the
hernia above described, the viscus in this case is protruded from the

Fig. 236.—Internan VInw OF THE
VESSELS RELATED TO THE GROIN.

A portion of the wall of the abdo-
men and pelvis of the left side, seen
from behind. 1, symphysis of the
pubis; 2, irregular surface of the
hip-bone separated from the sacrum ;
3, ischial spine ; 4, ischial tuberosity ;
5, obturator internus; 6, rectus,
covered with an elongation from 7,
fascia transversalis ; 8, fascia iliaca
covering the iliacus muscle ; 9, psoas
magnus cut; 10, tiac artery; 11,
iliac vein; 12, epigastric artery and
its two accompanying veins ; 138, vessels
of the spermatic cord, entering the
abdominal wall at the internal ring
the vas deferens joining them from
below ; 14, two obturator veins ; 15,
the obliterated umbilical artery.

abdomen to the groin directly
through the lower end of the
canal, at the external abdomi-
nal ring. At the part of the
abdominal wall through which the direct inguinal hernia finds its way,
there is recognised on its posterior aspect a triangular interval,

Fig. 237.—A Drrecr Incurnan Her- Fig. 237.
NIA ON THE LEFT SIDE, COVERED
BY THE CONJOINED TENDON OF THE
INTERNAL OBLIQUE AND TRANS-
VERSALIS Muscues.

1, aponeurosis of the external ob-
lique ; 2, internal oblique turned up ;
3, transversalis muscle; 4, fascia
transversalis ; 5, spermatic cord ; 6,
the hernia. A small part of the epi-
gastric artery is seen through an
opening made in the transversalis
fascia.

the sides of which are formed
by the epigastric artery, and
the margin of the rectus mus-
cle, and the base by Poupart’s
ligament. It is commonly
named the triangle of Hessel-
bach. Through this space the
hernia is protruded, carrying
before it a sac from the fossa of the peritoneum internal to the obliterated
hypogastric artery ; and it is in general forced onwards directly into the
external abdominal ring.

The coverings of this hernia, taking them in the order which they
are successively applied to the protruded viscus, are the following:—

z2

340 SURGICAL ANATOMY OF HERNIA,

The peritoneal sac and the subserous membrane which adheres to it,
the fascia transversalis, the conjoined tendon of the internal oblique

hs Fig. 238.—A Sma Os1iiquE AND A Dinncr
Fig. 238. = zs
InaguinaL HERNIA, ON THE Ricut Sipr.

1, tendon of the external oblique turned
down ; 2, internal oblique turned up ; 3,
transversalis ; 4, on its tendon above a part
of the epigastric artery, which has been ex-
posed by dividing the fascia transversalis. ;
5, the spermatic cord (its vessels separated) ;
6, a bubonocele ; 7, direct hernia protruded
at the conjoined tendon of the two dezper
muscles, and covered by a prolongation of
the fascia transversalis.

and transverse muscles, and the in-
tercolumnar (external spermatic)
fascia derived from the margin of
the external abdominal ring, to-
gether with the superficial fascia
and skin. With regard to the con-
joined tendon the hernia may be
covered by it, or may pass through
an opening in its fibres, or may
escape beneath it.

The spermatic cord is commonly placed behind the outer part of the
hernia. ‘he hernial sac is not, however, in contact with the vessels of
the cord. The investments given from the fascia transversalis to those
vessels and to the hernia respectively, are interposed.

But the point at which the internal inguinal hernia passes through
the triangle of Hesselbach is subject to some variation. Instead of
pushing directly through the external abdominal ring (the most frequent
position), the hernia occasionally enters the inguinal canal nearer to the
epigastric artery, and, passing through a portion of the canal to reach
the external ring, has therefore a certain degree of obliquity. This form
of hernia is frequently called internal obligue inguinal. Direct inguinal
hernia is very rarely met with in the female. In the single case
observed by Richard Quain as well as in the few cases found recorded
in books, the hernia though not inconsiderable in size was still covered
by the tendon of the external oblique muscle.

FEMORAL HERNIA.

A femoral hernia leaves the abdomen at the groin, passing beneath
the lower margin of the broad abdominal muscles, and over the anterior
border of the hip-bone immediately at the inner side of the large femoral
blood-vessels. It takes its course through the innermost compartment
of the sheath of the femoral vessels till it reaches the saphenous opening,
when it turns forwards through the opening towards the front of the
thigh, and is even bent upwards in the groin.

The femoral sheath is a somewhat funnel- shaped structure em-
bracing the upper parts of the femoral artery and vein. It is wide
superiorly, but embraces the vessels closely below. It is formed by the
lining fascize of the abdomen, the transversalis fascia being in front,
and the iliac fascia behind. On removing its anterior wall the sheath

FEMORAL HERNIA. 341

is found to be divided into three compartments, by fibrous septa ; the
outer compartment containing the femoral artery, the middle, the

Fig. 239.—Tre Groin or THE RIGHT Fig. 239.
SIDE DISSECTED sO AS TO DISPLAY
THE Deep FemoraL ARCH.

1, the outer part of the femorai
arch ; 1’, part of the tendon of the
external oblique muscle, with external
inguinal ring, projecting through
which is seen a portion of the sper-
matic cord cut; 2, the femoral arch
at its insertion into the spine of the
pubis, and to the outer side the
fibres of Gimbernat’s ligament ; 3,
the outer part of the femoral sheath ;
4, the spermatic cord ; 5, the deep
femoral arch—its inner end, where it
is fixed to the pubis; 6, internal
oblique muscle; 7, transversalis ;
below this the transversalis fascia
continued into the femoral sheath
under the deep femoral arch ; 8, con-
joined tendon of the internal oblique
and transversalis muscles ; 9, a band
of tendinous fibres directed upwards
behind the external abdominal ring.

femoral vein, and the inner being occupied merely by lymphatic vessels,
a gland, and some fat. This inner compartment is about half an inch
long, and from its being the passage through which the hernia descends,
has been called the femoral or crural canal. The upper extremity of
the canal presents a rounded aperture towards the cavity of the
abdomen, usually of sufficient size to admit the point of the forefinger ;
its size, however, varies in different persons, and it is larger in the
female than in the male. This aperture is called the femoral ring, and
is covered when viewed from the inside by peritoneum, and beneath
that by the subperitoneal connective tissue, which here forms the erwral
septum (Cloquet). On three sides the ring is bounded by very un-
yielding structures. In front are the femoral arches, the superficial
being formed by Poupart’s ligament, and the deep by a strong bundle
of fibres, which, springing from the under surface of Poupart’s ligament
outside the femoral vessels, extends across the forepart of the femoral
sheath and widening at its inner end, is fixed to the pectineal line
behind Gimbernat’s ligament. Behind the ring is the hip-bone covered
by the pectineus muscle and the pubic layer of the fascia lata ; on the
outer side lies the external iliac vein, but covered with its sheath ; and
on the inner side are several layers of fibrous structure connected with
the pectineal line—namely, Gimbernat’s ligament, the conjoined tendon
of the two deeper abdominal muscles, and the fascia transversalis, with
the deep femoral arch. The last-mentioned structures—those bounding
the ring at the inner side—present respectively a more or less sharp
margin towards the opening.

Relations to blood-vessels.—Besides the femora! vein, the posi-
tion of which has been already stated, the epigastric artery is closely
connected with the ring, lying above its outer side. It not unfre-
quently happens that an aberrant obturator artery descends into the

342 SURGICAL ANATOMY OF HERNIA.

pelvis at the outer side of the ring, or immediately behind it; and in
some rare cases that vessel passes over the ring to its inner side. An
obturator vein also has occasionally the same course ; and small
branches of the epigastric artery will be generally found ramifying on
the posterior aspect of Gimbernat’s ligament. In the male the sper-
matic vessels are separated from the canal only by the femoral arch.

Fig. 240.—Virw OF THE RELATIONS OF
THE VESSELS OF THE GROIN TO A
FremoraL Hernia, &c. (from R.
Quain). +
In the upper part of the figure a

portion of the flat muscles of the
abdomen has been removed, displaying
in part the transversalis fascia and
peritoneal lining of the abdomen; in
the lower the fascia lata of the thigh is
in part removed and the sheath of the
femoral vessels opened : the sac of the
femoral hernial tumour has also been
opened.

a, anterior superior spinous process:
of the ilium ; 0, aponeurosis of the ex-
ternal oblique muscle above the exter-
nal inguinal aperture ; c, the abdomi-
nal peritoneum and_ fascia trans-
versalis; ad, the iliac portion of the
fascia lata near the saphenous opening ;
e, sac of the femoral hernia ; 1, points.
to the femoral artery ; 2, femoral vein
at the place where it is joined by the
saphenous vein; 3, epigastric artery
and vein passing up towards the back
of the rectus muscle; +, placed upon
the upper part of the femoral vein,
close below the common trunk of the
epigastric and an aberrant obturator artery ; the latter artery is seen in this case to pass
close to the vein and between it and the neck of the hernial tumour.

Obl

\
\{
SY,

Descent of the hernia.—When a femoral hernia is being formed,
the protruded part is at first vertical in its course ; but at the lower end
of the canal it bends forward at the saphenous opening, and, as it
increases in size, ascends over the iliac part of the fascia lata and the
femoral arch. Within the canal the hernia is very small, being con-
stricted by the unyielding structures which form that passage; but
when it has passed beyond the saphenous opening, it enlarges in the
loose fatty layers of the groin ; and, as the tumour increases, it extends
outwards in the groin towards the iliac spine of the hip-bone.

Coverings of the hernia.—The coverings of a femoral hernia in
order from within outwards are, the peritoneum (which forms the sac);
the septum crurale and the sheath of the femoral vessels. These two
structures combined constitute a single very thin covering, known as
the fascia propria of the hernia (Cooper). It sometimes happens that
the hernia is protruded through an opening in the sheath, which there-
fore in that event does not contribute to form the fascia propria. Lastly
the hernia is covered by the cribriform fascia, covering the saphenous
opening ; the superficial fascia and skin.

THE BLOOD-VESSELS. 343

SECTION IV.—ANGJOLOGY,
OR, DESCRIPTION OF THE BLOOD-VESSELS AND
ABSORBENT VESSELS.

THE vascular system, as a whole, comprehends two sets of vessels,
viz., those carrying blood and those carrying lymph or chyle. The
first, constituting the sanguiferous system, includes the heart or central
propelling organ and the peripheral channels for the blood, viz., the
arteries, capillaries and veins. The absorbent system includes the
smaller and larger lymphatic and lacteal vessels, together with the
lymphatic and mesenteric glands with which many of these vessels are
connected. The descriptive anatomy of the heart is given along with
that of the thoracic viscera in the second volume: the account of the
minute structure of the blood-vessels and of the lymphatic vessels and
glands will be found in the part of the same volume which treats of
the General Anatomy. Under the present division, therefore, will be
brought only the descriptive anatomy of the principal blood-vessels and
absorbent vessels.

1.—BLOOD-VESSELS. ARTERIES AND VEINS.

The descriptive anatomy of the blood-vessels includes an account of
their form, position, mode of division, distribution, anastomosis with
each other, and relation to other parts. Seeing, however, that the
blood-vessels are subject to frequent variations, while the most constant
forms and modes of distribution are described as the normal, it will be
necessary also to make frequent reference to the more important
varieties which have been observed.

The varieties of blood-vessels may consist either of a deviation from
the usual size of the channels or from their usual position and their
connection with other vessels. Thus, they may be described as con-
sisting in differences of origin from the main stem, or from a branch,
or from quite another source than that which is the most common
or usual. But some varieties are so common that it becomes doubtful
which form is to be described as normal.

Many of the vascular varieties are not only compatible with life,
but cause no disturbance whatever in the performance of the ordinary
functions of the body. Others are of such a nature as to be com-
patible only with the conditions of the circulation subsisting during
foetal or intra-uterine life, and therefore prove fatal at birth. Some
are of considerable interest from their frequency, and others from their
existing in situations which are liable to diseases requiring surgical
operations.

Many vascular varieties repeat forms which are natural in different
species among the lower animals ; others are obviously due to the per-
sistence of early foetal forms of distribution ; and not a few are expli-
cable on the supposition of abnormal enlargement or diminution of
naturally existing vessels.

THE BLOOD-VESSELS.

344.

Fig. 241

PULMONARY ARTERIES AND VEINS. 345

Fig. 241.—Generau Virw or tHe Heart Ann Broop-VEsseLs, FROM BEFORE AND
FROM THE RIGHT SIDE IN A Maur Apvuur. }

A, Right auricle; B, left auricular appendix; C, right ventricle ; D, part of the
left ventricle ; I, aortic arch, and descending aorta ; I, trunk of the pulmonary artery
dividing into its right and left branches, and connected to the aorta by the cord of the
ductus arteriosus ; III, vena cava superior ; IV, vena cava inferior.

1, innominate artery and right carotid ; 1’, left carotid ; 2, right and left subclavian
arteries ; 3, intercostal vessels ; 4, inferior diaphragmatic arteries; below 4, the cceliac
axis and superior mesenteric artery ; 5, renal arteries ; 6, 6’, the spermatic arteries ;
below 6, the inferior mesenteric ; 7, 7’, right and left common iliac arteries; 8, 8’,
external iliac arteries ; 9, left epigastric and circumflex iliac arteries; 10, 10’, internal
iliac arteries; and between these two figures, the middle sacral artery ; 11, femoral
arteries ; 2, profunda femoris artery of the left side.

a, right brachio-cephalic vein ; a’, the left; 6, 6’, right and left subclavian veins ; 0”,
the cephalic vein of the right arm ; ¢, c’, internal jugular veins ; c", right facial vein
joining the internal jugular ; d, external jugular veins formed by the posterior auricular
and temporal ; d’, anterior jugular veins with the transverse joining the external jugular ;
€, azygos vein passing over the root of the right lung; f, the hepatic veins ; g, origin of
the renal veins ; to the sides are seen the kidney and the suprarenal bodies ; 9’, right,
g’, left ureter; h, right spermatic vein ; h’, the left, joining the left renal vein; 7, ¢,
common iliac veins ; 7, 2’, external iliac veins; /, fomoral veins; J, saphenous vein of
the right side.

For fuller information on the natural and abnormal distribution of
the blood-vessels, the reader may consult the works of Haller and
Tiedemann, and more especially the ‘ Anatomy of the Arteries,” by
Richard Quain, 1844; the third volume of Henle’s “ Systematic Work,’’
1868, in which a connected view of the varieties is given; and other
special treatises.

The sanguiferous system consists of two great divisions, compre-
hended in the lesser or pulmonic and the greater or systemic circula-
tions. To the former belong the pulmonary arteries and veins, which
will be first described.

PULMONARY ARTERIES AND VEINS.

PULMONARY ARTERY.

The main pulmonary artery is a short wide vessel, which carries
the dark blood from the right side of the heart to the lungs. It arises
from the infundibulum or conus arteriosus of the right ventricle, and
passes for the space of nearly two inches upwards, and at the same time
backwards and to the left side, to reach the concavity of the aortic arch,
where it divides into two branches—the right and left pulmonary arte-
ries. ‘The mode of attachment of the main pulmonary artery to the
base of the ventricle has already been fully noticed. At each side of its
commencement is the corresponding coronary artery springing from
the aorta, and close to its side are the two auricular appendages. It is
at first in front of the aorta and conceals the origin of that vessel ; but
higher up, where it lies in front of the left auricle, it passes to the left
side of the ascending aorta, and is finally placed bencath the middle
part of the arch. ‘The pulmonary artery and the aorta are united to-
gether by connective tissue and by the serous layer of the pericardium,
which for the space of about two inches forms a single tube around
both vessels. Rather to the left of its point of bifurcation it is con-
nected to the under side of the aortic arch by means of a short fibrous
cord, which passes obliquely upwards, backwards, and to the left. This

346 THE AORTA,

is the remains of the ductus arteriosus, a large vessel peculiar to the
foetus, which has been already described.

The right pulmonary artery, longer and somewhat larger than the
left, runs almost transversely outwards behind the ascending aorta and
the superior vena cava into the root of the right lung, where it imme-
diately begins to divide in the usual manner of arteries.

The left pulmonary artery, shorter than the right, passes horizon-
tally in front of the descending aorta and left bronchus into the root
of the left lung, to undergo its ramification.

The right and left pulmonary arteries, at the root of the lung, both
lie in front of the bronchus and behind the veins. On the right side
the bronchus is highest and the veins lowest, while on the left side the:
bronchus sinks to a level between the artery and veins.

PULMONARY VEINS.

The pulmonary veins are four short venous trunks which convey the
red blood back from the lungs to the left side of the heart, and which
are found, two on each side, in the root of the corresponding lung.
The two veins of the right side, which are longer than those of the
left, pass below the right pulmonary artery, and behind the superior
vena cava, the right auricle, and the aorta, to enter the left auricle.
Not unfrequently a third smaller vein exists on the right side in
connection with the third lobe of the right lung. The two left pul-
monary veins run a shorter course to reach the auricle, passing in
front of the aorta. The distribution of the pulmonary capillaries is
exclusively to the membrane lining the air cells of the lungs.

The varieties of the pulmonary arteries will be referred to along with those of
the aorta.

SYSTEMIC ARTERIES.

THE AORTA.

The aorta, the large main trunk of the systemic arteries, is situated
partly within the thorax and partly in the abdomen. It commences at
the left ventricle of the heart, and after arching over the root of the
left lung, descends in front of the vertebral column, and passing through
the diaphragm into the abdominal cavity, ends opposite the fourth
lumbar vertebra, by dividing into the right and left common iliac
arteries. In this course the aorta forms a continuous undivided trunk,
which gradually diminishes in size from its commencement to its ter-
mination, and gives off larger or smaller branches at various points.
Different parts of the vessel have received particular names, derived
from their position or direction. The short curved part, which reaches
from the ventricle of the heart to the side of the third dorsal vertebra,
is named the arch; the straight part, which extends from that vertebra
to the diaphragm, is called the thoracic aorta ; and the remainder of the
vessel, down to its bifurcation, is designated the abdominal aorta.

ARCH OF THE AORTA.

The arch of the aorta commences at the upper part of the base
of the left ventricle of the heart, behind the pulmonary artery. At
first it passes upwards and to the right side, somewhat in the direction
of the heart itself, and crosses obliquely behind the sternum, approach-

THE ARCH OF THE AORTA, 347

ing at the same time more nearly to that bone. Having gained the
level of the upper border of the second costal cartilage of the right side,

Fig. 242, A.—TTax Fig. 242,
AORTA FROM BEFORE,
WITH: THE ORIGINS OF
ITS PRINCIPAL BRANCHES
(R. Quain). 4

1, the aorta at the
place where it has been
separated from the left
ventricle, showing the
semilunar valves.in a
closed condition, the
sinuses of Valsalva, and
the origin of the right
and left coronary arte-
ries; 2, the ascending
part of the arch, with
the dilatation termed
sinus ; 3, the third part
of the arch ; 4, innomi-
nate artery; 5, left
carotid; 6, Jeft subcla-
vian; 7, concavity of
the middle part of the
arch ; and farther down
the aorta, 7, 7, indicate
two out of the series of
intercostal and lumbar
arteries : the cesophagea]
arteries are also seen
rising from the front of
the thoracic aorta; 8, 8,
right and left renal arte-
ries ; 9, 9, right and left
common iliac arteries ;
10, middle sacral artery ;
11, one of the inferior
diaphragmatic arteries ;
+, the cceliac axis ; 12,
the gastric artery; 13,
the hepatic; 14, the
splenic; 15, superior
mesenteric ; 16, inferior
mesenteric ; 17, 17, right
and left spermatic arte-
ries.

Fig. 242, B. — Tur
sAME AORTA FROM
BEHIND, (R. Quain). 3

The numbers have the
same signification as in
A. The origin of tne
right and left inter-
costal arteries close to
each other from near the
middle line of the posterior wall of the aorta is shown.

the vessel alters its course, and is directed upwards, backwards, and to
the left side, then directly backwards, in contact with the trachea, to the
left side of the body of the second dorsal vertebra. Arrived at that point,

348 THE AORTA,

it bends downwards, inclining, at the same time, a little towards the
middle line ; and at the lower border of the body of the fourth dorsal
vertebra, on its left side, the arch terminates in the descending portion
of the vessel. Near the base of the heart the aorta is larger than else-
where, and presents externally three small bulgings of nearly equal
size, corresponding with the dilatations which form the sinuses of Val-
salva or sinuses of the aortic valves, described with the heart. Two of
these sinuses are placed anteriorly and one posteriorly, and in the two
anterior sinuses are seen the orifices of the two coronary arteries of the
heart, the first branches given off by the aorta.

From the difference in the direction and connections of different
portions of the arch it is described as consisting of an ascending, a trans-
verse, and a descending portion.

The ascending portion of the arch of the aorta is placed at its com-
mencement behind the sternum, on a level with the lower border of the
third costal cartilage of the left side: and it rises as high as the upper
border of the second costal cartilage of the right side. Its length is
about two inches or two inches and a quarter; and its direction is
curved. In most cases there exists along the right side a dilatation,
named the great sinus of the aorta. ‘This dilatation varies in size in
different bodies, and occasionally is not to be detected.

This portion of the aortic arch is for the greater part of its length
enclosed in the same sheath of pericardium with the pulmonary artery
in such a manner that both vessels are covered by the serous mem-
brane, except where they are in contact with each other.

At its commencement the ascending part of the arch is in contact
anteriorly with the pulmonary artery, and with the right auricuiar
appendage ; but, further up, the aorta passes to the right side and the
pulmonary artery to the left, and thus the aorta comes into view.
It then approaches very near to the sternum, from which it is separated
only by the pericardium, by some connective tissue, and by the remains
of the thymus gland lodged in the mediastinal space; the descending
vena cava lies on the right side, and the pulmonary artery passes back-
wards on the left; while behind are placed the structures forming the
root of the right lung.

The second or éransverse part of the arch is covered on the left side
by the left pleura and lung, and is placed immediately in front and to
the left of the trachea, the cesophagus and the thoracic duct. The
upper border of the transverse part of the arch has in contact with it
the left innominate vein; and from it are given off the large arteries
(innominate, left carotid, and left subclavian), which are furnished to
the head and the upper limbs. ‘The lower or concave border overhangs
the bifurcation of the pulmonary artery, and is connected with the left
branch of that artery by the remains of the ductus arteriosus. This
part of the arch is crossed in front by the left pneumogastric phrenic
and superficial cardiac nerves ; and the recurrent laryngeal branch of
the pneumogastric turns upwards beneath and behind it.

The descending portion of the arch rests against the left side of the
body of the third and fourth dorsal vertebrae, and is covered by the left
pleura and the root of the left lung. To the right side of this part of
the arch is the cesophagus with the thoracic duct.

BrancHEs.—The branches given off from the arch of the aorta are
five in number. Two of these, named the coronary arteries of the

BRANCHES OF THE AORTA. 349

Fig. 243.—Virw oF THE
THORACIC AND UPPER
PART OF THE ABDOMINAL
AORTA, SHOWING THEIR
PRINCIPAL RELATIONS
ART es

a, the hyoid bone; 6,
placed on the anterior
scalene muscles, points to
the upper part of the pneu-
mogastric nerves; ¢, the
trachea below the isthmus
of the thyroid gland, and
lower down the same letter
is on the left bronchus ; ¢’,
one of the divisions of the
right bronehus emerging
from behind the aorta ;
in the hollow of the aortic
arch, above 5, are seen the
cord of the ductus arteri-
osus cut short, and the left
recurrent nerve passing
below the arch; +, is placed
on the right side between
the recurrent nerve and the
vertebral artery as they
pass upwards ; d, the ceso-
phagus ; e, upon the right
crus of the diaphragm, and
farther down e’, mark the
receptaculum chyli of the
thoracic duct, and its com-
mencement by the lumbar
plexus of lymphatic vessels
and efferent mesenteric lac-
teal vessels ; f, on the
third, seventh, and eleventh
ribs, points to the vena
azygos and superior imter-
costal veins of the right

side ; g, kidney ; g’, supra- \\ 2 AN ia 3 ea

renal body ; h, body of the \ \\ UMN in 2h Via, Zi.

fourth lumbar vertebra. SRV \ SS a aa j
ZI, sinus of the aortie \ (qty p\\ 2 wd

arch or ascending part of
the arch: below this the
semilunar valves are seen
closed and distended by
injection ; J’, posterior part
of the arch, upon which
the left pneumo-gastric
nerve is seen descending ;
I”, descending thoracic part
of the aorta ; //, abdominal
aorta emerging from be-
tween the crura of the
diaphragm,

Branches of the arch and thoracic aorta ; 1, right and left coronary arteries ; 2, inno-
minate ; 3, left carotid; 4, left subclavian ; 5, bronchial arteries; 6, 6, cesophageal
arteries: the lower figure points by a line to the thoracic duct ; 7, intercostal arteries,
marked in the sixth and seventh intercostal spaces.

Branches of the abdominal aorta; 8, inferior diaphragmatic arteries cut short; 9,
coeliac axis with the gastric, splenic, and hepatic arteries cut short; 10, placed on the

350 THE AORTA.

aorta below the superior mesenteric artery (cut short) and the origin of the renal arteries ;
a little below this the origin of the spermatic arteries ; below Z/, the inferior mesenteric
artery, 11, 11, two of the lumbar arteries.

heart, comparatively small, arise from the two anterior sinuses of Valsalva,
and are distributed to the walls of the heart. The other three are large
primitive trunks, which supply the head and neck, the upper limbs,
and, in part, the thorax, and usually arise from the middle or highest
part of the arch, in the following order :—first, the drnominate or
brachio-cephalic artery ; second, the left carotid ; and, third, the (lft
subclavian artery. The origin of the left carotid artery is usually
somewhat nearer to the innominate artery than it is to the subclavian
artery of its own side.

Varieties.—It will be proper in this place to refer to the varieties which affect
the whole aorta, as well as to those of the pulmonary arteries. The former may
‘be distinguished, according as they occur in the whole length of the vessel, or
belong to one or other of its parts, those which are very frequent in the arch
being especially deserving of notice. These last are of peculiar interest, but as
the full explanation of their mode of formation is connected with the history of
foetal development, the reader is referred to the chapter on that subject for
elucidation of the present outline of the nature of the varieties which is intro-
duced in this place.

1. The Aorta may vary in its position and extent. Thus the height to which
the arch rises in the upper part of the chest is found to be subject to variation to
the extent frequently of from one to two vertebral spaces ; more rarely to a
greater extent, so that while in some instances the summit of the arch has been
on a level with the top of the sternum, in other cases it has been as low as the
fourth or fifth dorsal vertebra.

The distance to which the aorta extends downwards depends on the seat of its
division into the common iliac trunks, which frequently varies to the extent of
one of the lumbar vertebrz, so that the place of division may be as low down as
on the fifth, or as high upas on the third, In other rarer cases the division
occurs still higher.

The position of the aorta with reference to the middle line or vertebral column
is also subject to some variation, but such deviation to the side 1s more frequently
the result of pathological changes than of congenital malformation.

A very remarkable malformation of the aorta consists in the greater or less
division of the vessel through a part or the whole of its channel into two
closely united tubes, by a median septum running through the cylindrical tube
from before backwards, or slanting from side to side, as in the cases observed by
Cruveilhier, Vrolik, Schréder Van der Kolk, and Allen Thomson, which when not
due to pathological changes may admit of explanation on the supposition of the
fusion of the original double embryonic aorta having remained incomplete.

2. The Varieties of the Stems, or main trunks of the aorta and pulmonary
‘artery, are intimately connected and usually associated with malformations of the
heart, and frequently with the persistence of the ductus arteriosus. These first
parts of the two great arteries, specially enclosed by the pericardium, are derived
from the arterial bulb of the foetal heart, and are liable to variations which may
be traced to deviations from the natural mode of their septal division, and of
their union with the left or right ventricles of the heart respectively. Thus these
two arterial trunks may be transposed, or each one may be connected with the
ventricle to which it does not naturally belong, i.c., the pulmonary artery with
the left, and the aorta with the right ventricle. Or the arterial trunks may
communicate together more or less freely by deficiency of the septum between
them. Or one of the vessels may be nearly or entirely obliterated; while the
other, from unnatural openings left between them, serves as the channel for the
stream of blood belonging to both vessels. Or the aorta and pulmonary arteries
may be entirely united in one simple stem in connection with a simple heart
similar to that of fishes.

VARIETIES OF THE AORTIC ARCH. 351

8. The Varieties in the Aortic Arch itself, along with which must be included
those of the ductus arteriosus, are intimately connected with the mode of develop-
ment of the fourth and fifth foetal branchial arteries. The natural aortic arch of
man, and of all mammalia, is a left one produced by the persistence and develop-
ment of the fourth left branchial arch: in birds it is the right arch which
forms the permanent aorta ; and in reptiles both the right and left fourth arches
remain patent.

Here it may be proper to call attention to the complete lateral transposition, %. ¢.,
from right to left and vice versd, which affects the aortic arch and pulmonary
vessels, as well as the other parts of the heart, when transposed with or without
the transposition of other viscera. Several cases of this kind have been accurately
recorded by various observers, and are usually unattended with any disturbance
of the functions or otherwise unnatural condition of structure. There is, in fact,
only a change of position, which may be best described by comparing it to
that in which the natural parts would appear if viewed by reflection from a
mirror. Although this transposition gives rise to no perceptible lesion of function,
yet from the direction of the apex of the heart towards the right, and other
aifferences from the natural position, its existence is capable of being ascertained
during life.

Fig. 244.—Dracram or THE Fa rat Aortic
ARCHES, SHOWING THEIR TRANSFORMA-
TIONS INTO THE PERMANENT VESSELS OF
THE MamMat (after Rathke). A.T.

A, to the right of the primitive arterial
bulb, now divided into aortic and pulmo-
nary stems, the latter in front ; a, the right,
a, the left aortic roots; A’, the descending
aorta ; on the right side, the double out-
lines, 1, 2, 3, 4, 5, indicate the five primi-
tive branchial vascular arches ; on the left
side, I, IJ, Il], IV, mark the seat of the
four branchial or pharyngeal clefts ; c, the
place of division of the aortic arches into
two anteriorly, between the common carotid
arteries ; cc, the permanent external caro-
tids ; cz, the right, cz’, the left internal
carotids ; s, the right, s’, the left subcla-
vians ; v, the right, v’, the left vertebrals ;
the fourth right arch forms the innominate
trunk, and passes on to v and s, the right
vertebral and subclavian arteries ; the fourth
left arch passes to a’ as permanent aortic
arch ; P, pulmonary arteries springing from
the fifth left arch, which at d is continued
into the left aortic root as ductus arteriosus ;
pn, right, pn’, left pneumogastric nerves. The permanent systemic arteries are repre-
sented in deep shade.

The aortic arch has been observed completely double in two remarkable cases,
known as those of Malacarne and Hommel, and various less complete cases of a
similar kind have been observed. Hommel’s case admits of being explained on
the supposition simply of both the right and left fourth branchial arches having
remained pervious, and undergone equal development. The pulmonary artery was
situated to the left of the main aortic stem ; the right and left aortic arches
embraced closely the trachea and gullet in a ring, and each arch gave rise to a
common carotid and subclavian artery in the order now mentioned. Malacarne’s
case is different, and seems to have been complicated with some remarkable
abnormal mode of development of the arterial stem. The two arches, as in
Hommel’s case, embraced the trachea and gullet, but they divided close to the
heart, so as to receive the pulmonary stem between them ; and each gave rise to
a subclavian, an external, and an internal carotid artery, in the order now stated,

352 THE AORTA.

which cannot be explained by what is as yet known of the modes of develop-
ment of the branchial vascular arches.

The existence of a right aortic arch, that is, one passing to the right of the
trachea and gullet, instead of the usual left arch, is easily explained on the sup-
position of the fourth right branchial arch having been developed instead of the
left ; and accordingly there are instances of this variety, in which no other
deviation from the natural condition of the parts exists, beyond what proceeds
from the change of side taken by the aortic arch, leading to the innominate or
brachio-cephalic artery being a left one, or furnishing the left subclavian and
carotid arteries, and the succeeding vessels being the right carotid and right sub-
clavian. The recurrent laryngeal nerve forms its sling on the right side, round
the aortic arch, and on the left round the arch of the subclavian artery.

Under the same division as the foregoing might also be brought those remark-
able and numerous cases of varieties in the mode of closure of the ductus arteri-
osus and of its union with the aortic root or other vessels; but these and other
modifications of the variations of the arches may best fall under the next
division.

4, Varieties of the posterior part of the arch and ductus arteriosus belong pro-
perly to the changes occurring in connection with the posterior embryonic aortic
roots.

One of the most frequent varieties of this group is that of the subclavian artery
(of the right side, when the aortic arch is left or normal) rising, as it has been
described, from the back part of the arch, or fourth in the series of vessels pro-
ceeding from it, but which, according to embryological elucidation, would be more
correctly designated as the subclavian artery formed in connection with one of
the posterior aortic roots; the natural anterior root and arch being abnormally
closed. In such cases the subclavian artery takes its course behind the trachea
and gullet to reach its subsequent natural place as it passes between the scalene
muscles and over the first rib.

O45 Fig. 245.—DIAGRAM OF THE NATURAL ORIGIN OF VESSELS FROM
ag eG, the Aortic ARCH AS COMPARED WITH THE DISPLACED SUB-
CLAVIAN ARTERY.

(I). The normal disposition ; (II), the right subclavian artery
displaced or proceeding from the right aortic root. <A, A,
ascending and descending parts of the thoracic aorta; P, pul-
monary stem; d, ductus arteriosus ; a, right aortic root or its
remains ; a’, left aortic root; c, common carotid arteries, 2,
innominate artery ; s, right, and s’, left subclavian arteries ; v,,
right, and 2’, left vertebral arteries.

A similar variety may occur in an instance of right
aortic arch, in which case it is the left subclavian artery
which takes the abnormal course. In both examples of
this variety, the anterior part of the subclavian arch being
absent, the inferior laryngeal nerve is not recurrent, but
passes directly to the larynx, without being drawn down
as a sling or loop by the subclavian artery.

There are also many instances of transitions or grada-
tions between these cases and the completely double aortic
arch. See a paper on “ Varieties of the Arch of the
Aorta,” by Turner, in Brit. and For. Med. Chir. Review.
1863, and “ Description of a Case of Right Aortic Arch,”
by Allen Thomson, in Glasg. Med. Journ. 1862, in which
such cases are more fully explained, and also the works
of Henle, Hyrtl and Struthers.

In some of the instances of aberrant subclavian artery
of the kind now referred to, the vertebral artery is
detached from the subclavian, and rises directly from the arch of the aorta.

Under the same division may be brought those numerous varieties in ths
closure of the ductus arteriosus and its union with the aorta or other vessels.

THE CORONARY ARTERY. 3853

which have been observed ; the greater number of which it will be understood,
from the nature of the change in the circulation which takes place at birth, are
only compatible with intra-uterine life. Such are those cases in which the
pulmonary artery leads through the ductus arteriosus, or fifth branchial arch of
the left side into the descending aorta ; while the aortic arch itself is completely
separated by a constriction or even a complete closure of its tube from the
descending part of the aorta. It is remarkable, however, that in some rare cases
of the kind now referred to, life has been prolonged after birth, and the ductus
arteriosus having become closed, probably gradually, the descending aorta has
come to receive a full supply of blood from enlarged anastomosing vessels
(internal mammary, intercostal, &c.) passing between the vessels which rise from
the arch and those connected with the descending aorta.

Along with the same division may also be classed the series of converse cases,
in which the pulmonary arch being closed anteriorly, the pulmonary vessels have
received their supply of blood from the descending aorta. Such examples of the
origin of the pulmonary arteries from the aorta, as they have been styled, and
examples of the origin of the left, or in most rare cases of the right subclavian
artery from the ductus arteriosus or from one of the pulmonary arteries, are
explicable by reference to the same group of developmental phenomena.

5. The varieties in the number and position of the vessels springing from the
arch of the aorta are extremely numerous; some very frequent, others compa-
ratively rare. These vessels may be all collected into one trunk, or they may
rise separately from the aorta to the number of six. In the rare case of one
trunk, we may suppose the anterior aortic roots to be combined so as to collect
all the branches proceeding from them together, as naturally occurs in what is
called the anterior aorta of the horse.

The cases of two vessels from the arch may be of two kinds; one, which is the
commonest of all the varieties of the aortic vessels, in which the left carotid is
united with the innominate artery into a common stem: and the other, com-
paratively rare, in which there are two innominate or brachio-cephalic trunks,
as in birds.

Three is the normal number of branches rising separately from the arch in
man, and apes, and some other mammals. There is, however, a rarer form of
variety in which the number is the same, and in which, as occurs naturally in
some cetacea, the subclayians are both separate vessels, and the two carotids
spring from a common stem in the interval between them.

The commonest form of the condition in which there are four vessels rising
from the aortic arch, is that in which the sessile left vertebral artery rises
between the left carotid and subclavian arteries. A rarer form is that in which
the vessels rising from the arch are successively the right subclavian, the right
carotid, the left carotid, and the left subclavian arteries.

The number of five arteries proceeds from the division of the innominate into
subclavian and carotid, together with separate origin of the left vertebral artery.

In the case of six vessels proceeding from the single arch, of which there is an
instance described, the vessels were in the following order, which is that which
might be anticipated from the mode of development, viz., right subclavian,
vertebral and carotid, left carotid, vertebral and subclavian arteries.

There are, however, many other varieties and modifications of those already
mentioned, for which the fuller works already quoted may be referred to.

BRANCHES OF THE ARCH OF THE AORTA,

The coronary arteries are two small vessels, named right and left,
which arise from the root of the aorta in the upper parts of the two
anterior of the three sinuses of Valsalva, on a level with the margins
of the semilunar valves.

The right coronary artery about the size of a crow’s quill, runs
obliquely in the auriculo-ventricular groove towards the right side, and
thence along the posterior aspect of the heart, until it reaches the line of

VOL. I. : AA

354

THE AORTA.

separation between the two ventricles, where it divides into two branches.
The smaller of these continues transversely in the groove between the
left auricle and ventricle, approaching the termination of the transverse
branch of the left coronary artery ; while the other branch runs longi-
tudinally downwards along the posterior wall of the septum between
the ventricles, giving branches to each ventricle and to the septum

between them.

In its course the right coronary artery gives, besides the offsets
already noticed, small branches to the right auricle and ventricle, and

also to the first part of the pulmonary artery.

Along the right border

of the ventricle arather large branch usually descends towards the apex
of the heart, and gives offsets, in its progress, to the anterior and

posterior surfaces of the ventricle.

appendage.
ventricular sulcus, where it divides into two branches.
pursues a transverse direction, turning outwards and to the left side
in«the groove between the left ventricle and auricle, and approaching
at the posterior aspect of the heart the transverse branch of the right

coronary artery ; the other branch,
anterior surface of the heart along

grooye, to the right of the apex.

The left coronary artery supplies

Fig. 246.—Virw oF THE HEART AND
Coronary ARTERIES FROM BEFORE (R.
Quain). 3
The pulmonary artery has been cut short

close to its origin in order to show the first
part of the aorta. 1, anterior part of the
right ventricle ; 2, left ventricle ; 3, root
of the pulmonary artery; 4, ascending part
of the arch of the aorta ; 4’, the posterior
or descending part of the arch; between
these is seen the transverse or middle part
from which the brachio-cephalic arteries take
their origin; 4”, the descending aorta ;
5, the appendix and anterior part of the
right auricle ; 6, those of the left auricle ;
7, the right, and 7’, the left innominate or
brachio-cephalic veins joining to form the
vena cava superior; 8, the inferior vena
cava below the diaphragm ; 9, one of the
large hepatic veins ; +, placed in the right
auriculo-ventricular groove, points to the
right or posterior coronary artery; ++,
placed in the anterior interventricular
groove, points to the left or anterior coro-
nary artery.

The left coronary artery is rather
smaller than the preceding, and
arises from the left anterior sinus
of Valsalva. It passes behind and
then to the left side of the pul-
monary artery, appearing between
that vessel and the left auricular

At first it descends obliquely towards the anterior inter-

Of these, one

much the larger, descends on the
the line of the interventricular

some small branches at its com-

mencement to the pulmonary artery, to the coats of the aorta, and to

THE INNOMINATE ARTERY. 335

the left auricular appendage ; its two branches also furnish throughout
their course smaller offsets, which supply the left auricle, both ventricles,
and the interventricular septum.

It has been customary to describe the transverse branches of the coronary
arteries as anastomosing in the left atwiculo-ventricular sulcus, and the des-
ending branches as anastomosing near the apex of the heart, and this description
was never doubted till it was found by Hyrtl, as the result of separate injection
of these vessels, that the branches of one coronary artery cannot be injected with
material introduced into the other. (Nat. Hist. Review, 1861, p. 321.)

Varieties.—The coronary arteries have been observed in a few instances to
commence by a common trunk, from which they diverged and proceeded to their
usual destination. The existence of three coronary arteries is not a very rare
occurrence, the third being small, and arising close by one of the others. Meckel,
in one instance, observed four, the supplementary vessels appearing like branches
of one of the coronary arteries transferred to the aorta.

THE INNOMINATE ARTERY.

The innominate, or brachio-cephalic artery, the largest of the vessels
which proceed from the arch of the aorta, arises from the commence-
ment of the transverse portion of the arch, before the left carotid
artery. From this point the vessel ascends obliquely towards the right,
until it arrives opposite the sterno-clavicular articulation of that side,
nearly on a level with the upper margin of the clavicle, where it divides
into the right.subclavian and the right carotid artery. The place of
bifurcation would, in most cases, be reached by a probe passed back-
wards through the cellular interval between the sternal and clavicular
portions of the sterno-mastoid muscle. The length of the innominate
artery is very variable, but usually ranges from an inch and a half to
two inches.

This artery, lying for the most part within the thorax,'is placed
behind the first bone of the sternum, from which it is separated by the
sterno-hyoid and sterno-thyroid muscles, and a little lower down by the
left innominate vein, which crosses the artery at its root. The lower
part of the innominate artery lies in front of the trachea, which it
crosses obliquely: on its left side is the left carotid artery, with the
thymus gland or its remains ; and to the right is the ccrresponding
brachio-cephalic vein and the pleura.

No branches usually arise from this vessel.

Varieties. —The length of the innominate artery sometimes exceeds two inches,
and occasionally it measures only one inch or less. Its place of division is a
point of surgical interest, inasmuch as upon it in a great measure depends the
accessibility of the innominate in the neck, and the length of the right subclavian
artery. It has sometimes been found dividing at a considerable distance above
the clavicle, and sometimes, but less frequently, below it. Though usually des-
titute of branches, this vessel has been observed to supply a thyroid branch, the
thyroidea ima, and sometimes a thymic branch, or a bronchial, which descends in
front of the trachea.

The thyroidea ima is an occasional artery. When present, it usually arises (as
already stated) from the innominate trunk, but in some instances it has been observed
to come from the right common carotid artery, or from the aorta itself. More
rarely it arises from the right internal mammary, or the right subclavian. It is
of very different size in different bodies, and compensates in various degrees for
deficiencies or absence of the other thyroid arteries. It ascends to its destination
in front of the trachea, and its presence might therefore complicate the operation
of tracheotomy,

AA

356 ARTERIES OF THE HEAD AND NECK.

COMMON CAROTID ARTERIES.

POSITION AND RELATIONS—DIFFERENCE ON THE TWO SIDES.—The
common carotid arteries of the right and left sides of the body are nearly
similar in their course and position whilst they are in the neck; but

Fig, 247.

aH i

a \ 5

VA ==
OF
C2U-—“="_,

Lei 72 PLLA La
Vig. 247.—Vizw or tHE Rigor Common Carotip anp SupcnaviAN ARTERIES, WITH

THE ORIGIN OF THEIR BRANCHES AND THEIR Renarions (R. Quain). 4

The sterno-mastoid, sterno-thyroid, sterno-hyoid, and omo-hyoid muscles have been
removed, the trapezius has been detached from the outer part of the clavicle and turned
backwards, and the inner part of the clavicle has been removed : a, parotid gland near
the place where the duct of Stenson leaves it; 6, angle of the jaw and masseter muscle ;
ec, submaxillary gland, enclosed between the digastric and stylo-hyoid muscles ; d, divided
upper part of the sterno-mastoid muscle; e, front of the hyoid bone ; J, thyroid cartilage ;
g, isthmus of the thyroid gland ; h, the trachea; 7, 7’, the sawn ends of the clavicle, the
portion between them having been removed; 4, the first rib; Z, front of the sternum ;
m, scalenus medius ; 7, levator anguli scapule ; 0, deep surface of the trapezius ; p, on
the longus colli muscle, pointing to the pneumogastric nerve ; IV, the uppermost of the
nerves of the brachial plexus ; A, the innominate artery; 1, right common carotid artery ;

COMMON CAROTID ARTERIES, 357

1’, placed on the left sterno-thyroid muscle, points to a part of the left common carotid ;
2, internal carotid ; 2’, upper part of the internal jugular vein, which has been removed
between 7, and 2’; 3, and 4, external carotid ; 3 is placed at the origin of the superior
thyroid artery ; 4, at that of the lingual ; farther up the vessel may be seen the separa-
tion of the sterno-mastoid twig and the facial and occipital branches from the main vessel ;
5, is placed on the thyro-hyoid muscle between the hyoid and laryngeal branches of 5’,
the superior thyroid artery ; 6, the facial artery passing over the base of the jaw ; 7, the
superficial temporal artery ; 8, the first part, 8’, the third part of the subclavian artery ;
8”, the subclavian vein separated from the artery by the scalenus anticus muscle ; 9, is
placed on the scalenus anticus muscle in the angle between the transversalis colli and
suprascapular branches of the thyroid axis ; 10, outer part of the suprascapular artery ;
10’, transverse cervical branches passing into the deep surface of the trapezius ; 10”, the
posterior scapular artery, rising directly from the third part of the subclavian artery ; 11,
on the scalenus anticus muscle, points to the inferior thyroid artery near the place where
the ascending cervical artery of the neck is given off ; the phrenic nerve lies on the
muscle to the outside of the figure at 7, the suprasternal twig of the suprascapular artery

is shown.

they differ materially in their place of origin, and consequently in
their length and position, at their commencement. On the right side
the carotid artery commences at the root of the neck behind the upper
part of the sterno-clavicular articulation, at the bifurcation of the
innominate artery ; but on the left side the carotid arises within the
thorax, from the highest part of the arch of the aorta, very near the
origin of the innominate artery.

The left carotid is thus as a whole longer than the right, and its first
part is placed at some depth within the thorax. While within the thorax,
the left carotid ascends obliquely behind and at some distance from the
upper piece of the sternum and the muscles (sterno-hyoid and sterno-
thyroid) connected with that part of the bone ; it is covered in front
by the remains of the thymus gland, and is crossed by the left
innominate vein. This part of the artery lies in front of the trachea,
and of the cesophagus, which, at the root of the neck, deviates a little
to the left side; the thoracic duct is also behind it. The left carotid
artery here lies between the innominate and the left subclavian arteries,
and the vagus nerve is to its outer side.

In the neck the common carotid artery of either side reaches from
behind the sterno-clavicular articulation to the level of the upper border
of the thyroid cartilage, where it divides intc two great branches, of
which one is distributed to the cranium and face, and the other to the
brain and eye. ‘These divisions have, from their destination, been
named respectively the external and internal carotid arteries.

The oblique course taken by the common carotid artery along the side
of the neck is indicated by a line drawn from the sterno-clavicular arti-
culation to a point midway between the angle of the jaw and the mastoid
process of the temporal bone. At the root of the neck, the arteries of
opposite sides are separated from each other only by a narrow interval,
corresponding with the width of the trachea ; but, as they ascend, they
are separated by a much larger interval, corresponding with the breadth
of the pharynx and larynx. The carotid arteries have the appearance
of being placed farther back at the upper than at the lower part of the
neck, owing to the forward projection of the larynx above.

The common carotid artery is enclosed, together with the internal
jugular vein and the vagus nerve, in a common sheath, which is
continuous with the deep cervical fascia; the nerve, artery and
vein are, however, each contained in a separate fibrous investment

358 ARTERIES OF THE HEAD AND NECK.

within the sheath. The artery is deeply placed at the lower part of
the neck, but is comparatively superficial towards its upper end. It
is covered below by the sterno-mastoid, sterno-hyoid, and sterno-thyroid
muscles, in addition to the platysma and the layers of fascia between
and beneath the muscles ; and it is crossed opposite or near the lower
margin of the cricoid cartilage by the omo-hyoid muscle. From this
point upwards to its bifurcation, the vessel is covered by the sterno-
mastoid, by the platysma and fascia, and by the common integument ;.
and lies in a triangular space bounded by the sterno-mastoid, the omo-
hyoid, and the digastric muscles.

Posteriorly, t the artery is supported by the cervical vertebra, the
longus colli and rectus capitis anticus muscles intervening. Hence the
flow of blood through it may be commanded by pressure directed back-
wards against the vertebral column. The inferior thyroid artery crosses
behind the carotid sheath.

On the inner side the vessel is in contact with the trachea, the
thyroid body (which often overlaps the artery), the larynx, and the
pharynx. Along its outer side are placed the internal jugular vein
and the vagus nerve.

Relation to veins.—The internal Jugular vein is close to the artery
at the upper part of the neck, but, in approaching the thorax, the veins.
of both sides incline to the right, and hence that of the right side is.
separated from the artery by an angular interval, while that ‘of the left
side approaches the artery, and even lies in front of it at the lower part
of the neck.

Crossing over the upper part of the common carotid’ artery to join
with the jugular vein, are two or more superior thyroid veins, which
occasionally form a sort of plexus over the artery. A muddle thyroul’
vein not unfrequently crosses the artery about half way up the neck.

The anterior jugular vein, where it turns outwards under the sterno--
mastoid muscle to join the subclavian, crosses the lower part of the:
artery. This vein is generally of small size, but occasionally is rather
large, and is placed nearly over the carotid artery along the neck.

Relation to nerves—The descending branch of the hypoglossal
nerve, descendens noni, usually rests, together with the branches of
cervical nerves which join it, on the fore part of the sheath of the
carotid artery, and crosses it from the outer to the inner side: in some
instances this branch descends within the sheath between the carotid
artery and jucular vein. The vagus nerve lies within the sheath of the
vessels between the artery and vein posteriorly : it was in one case
observed to descend over the artery. The sympathetic nerve is placed
along the back of the sheath, between it and the vertebral muscles, and
the recurrent laryngeal nerve crosses inwards behind. the lower part of
the sheath.

The common carotid artery usually gives off no branch, and therefore
continues of equal size in its whole length, except at its bifurcation,
where a slight enlargement is observable.

Varieties.— Origin.—The right carotid artery occasionally arises directly from
the aorta, or in conjunction with the left carotid. When it arises from the aorta,
it is usually the first vessel from the arch, the subclavian being displaced ; but it
has been found to occupy the second place,—the right subclavian, or, very rarely,
the left carotid being the first.

The place at which the right carotid artery commences varies with the point

VARIETIES OF THE COMMON CAROTID ARTERY. 359

of bifurcation of the innominate artery. A change from the usual position on a
level with the upper border of the clavicle was found by R. Quain in the pvropor-

Fig. 248.—Dissrction or THE Riaut Sipe or THE Neck 10 sHow THE CAROTID AND
SupcLaAvian ARTERIES, &c. (from R. Quain). +4

a, angle of the jaw and masseter muscle ; 0, parotid gland; +, the posterior belly of
the digastric muscle ; c, submaxillary gland ; d, mylobyoid muscle below the anterior
belly of the digastric muscle ; e, upper belly of the omohyoid muscle ; e’, lower belly ;
f, sterno-hyoid muscle; g, sterno-thyroid ; 1, upon the sterno-mastoid muscle, points by
a line to the upper part of the common carotid artery ; 2, upon the scalenus anticus
muscle, points to the third part of subclavian artery ; 3, upon the scalenus medius, points
to the superficial transverse cervical artery crossing the axillary nerves ; 4, points to the
posterior scapular artery, passing under the levator scapule muscle ; 5, placed upon the
clavicle, points to the suprascapular artery; 6, external carotid artery; 6’, internal
carotid artery ; 7, upon the thyro-hyoid muscle, points to the superior thyroid artery
giving superiorly its hyoid branch ; 8, is placed upon the hyo-glossus muscle within the
arch of the lingual artery ; 9, placed on the stylo-hyoid muscle, indicates the facial
artery ; 10, origin of the occipital artery, from the root of which the small sterno-mastoid
artery is given off ; between the occipital and the facial arteries, +, upon the posterior
belly of the digastric muscle, points to the continuation of the external carotid artery
before entering the parotid gland.

360 ARTERIES OF THE HEAD AND NECK.

tion of about one case in eight and a half of those observed by him ; and it was
found to occur more frequently above than below that point.

The left carotid artery varies in its origin much more frequently than the
right. In the greater number of its deviations from the ordinary place of origin,
this artery arises from, or in conjunction with the innominate artery ; and in
those cases in which the right subclavian is a separate branch of the aorta, the
two carotids most frequently arise by a common trunk.

In cases of transposition, or of right aortic arch without other abnormality,
the left common carotid springs from a left innominate artery, which is the first
vessel to rise from the arch, and the right carotid is the second vessel.

Place of division —This often deviates somewhat from its usual position ; it
does so more frequently in an upward than in a downward direction. It is often
as high as the os hyoides, and occasionally much higher. It is found from time
to time opposite the middle of the larynx, and, in rare instances, opposite the
lower margin of the cricoid cartilage, or even lower. One case was observed by
Morgagni, in which the carotid artery, measuring one inch and a half in
length, divided at the root of the neck. (‘‘ De Sedibus et Causis Morborum,”
Epist. 29, Art. 20.) The common carotid artery has been found, as a very rare
occurrence, to ascend in the neck without dividing into its two usual terminal
branches ; the internal carotid artery being altogether wanting.

In two recorded cases the common carotid artery was absent, the external and
internal carotids arising directly from the arch of the aorta.

Relation to nerves—In one case the pneumogastric nerye was observed to
descend in front of the artery.

Occasional branches.—The common carotid artery sometimes gives origin at
its upper part to the superior thyroid artery, and. in some rare cases, to a
laryngeal or an inferior thyroid branch ; also, if a few instances, to the vertebral
artery.

SURGICAL ANATOMY OF THE COMMON CAROTID ARTERY.

As the common carotid does not in ordinary cases furnish any branch, a
ligature can be applied to any part of the vessel except immediately at its
commencement and termination. It is usually tied either immediately above
or below the omo-hyoid muscle, the operation above the muscle being pre-
ferred if possible because here the artery is more superficial, and is at the same
time free from the difficulties offered by the muscles lower down, and by the
superior thyroid veins, if the artery be secured near its bifurcation. An incision
three inches long is made from the level of the hyoid bone downwards along the
inner margin of the sterno-mastoid muscle.

Before dividing the integument it is well to ascertain whether the anterior
jugular vein be in the line of incision. The sterno-mastoid is slightly everted,
and the anterior belly of the omo-hyoid displayed, which last is then raised and
turned inwards. On the front of the sheath of the vessels may now be seen
the descendens noni nerve. The sheath is to be opened over the artery near the
trachea in order to avoid the internal jugular vein, and it is best to insert the
aneurism needle conveying the ligature on the outer side of the artery, for thus
the vein and the pneumogastric nerve will be most effectually avoided. Should
the internal jugular vein lie in front of the artery, as it sometimes does on
the left side, and especially at the lower part of the neck on that side, it will be
a source of much difficulty in completing the operation, and much caution will
be required in passing the aneurism needle with the ligature about the artery.
Should the operation be performed at the lower part of the neck, some fibres of
the muscles will require to be cut across in order to lay the artery bare with

facility ; and the necessity for this step increases in approaching towards the
clavicle,

EXTERNAL CAROTID ARTERY.
FORM AND PosITIon.—The external carotid artery, distributed mainly
to the face and to the walls of the cranium, is smaller than the internal
carotid in young persons: but the two are nearly of equal size in

EXTERNAL CAROTID ARTERY. 561

adults. It reaches from the point of division of the common carotid,
opposite the upper margin of the thyroid cartilage, to the neck of the
condyle of the lower jaw-bone, or a little lower, and there divides
into its two terminal branches, the temporal and the internal maxillary.
It diminishes rapidly as it ascends, owing to the number and size of
the branches which spring from 18.

At first the external carotid lies nearer to the middle line of the body
than the internal carotid; but it soon becomes superficial to that
artery, at the same time curving slightly forwards as it ascends to its
place of division. At its origin this artery is concealed by the sterno-
mastoid muscle, emerging from beneath which, it is covered only by the
platysma myoides and the fascia, and traverses the upper part of a
triangular intermuscular space bounded by the sterno-mastoid, omo-
hyoid and digastric muscles ; it then becomes deeply placed, passing
beneath the stylo-hyoid and digastric muscles, and finally becoming
embedded in the substance of the parotid gland. In the lower part of
its course it is in contact with the pharynx and hyoid bone; further
up it is separated by a portion of the parotid gland from the back of
the ramus of the lower jaw, and rests upon the styloid process and the
stylo-pharyngeus muscle, which, with the glosso-pharyngeal nerve, are
interposed between it and the internal carotid artery.

Relation to veins—This artery has usually no companion vein,
though it may be crossed superficially by small branches of the con-
tiguous veins; but, when the internal maxillary vein joins the deep
instead of the superficial jugular, it accompanies the external carotid.

Relation to nerves——Close to the digastric muscle the external
carotid artery is crossed by the hypoglossal nerve, and at a short dis-
tance from its upper end, in the substance of the parotid gland, by
the facial nerve. ‘Che glosso-pharyngeal nerve lies between it and the
internal carotid ; and the saperior laryngeal nerve is under both vessels.

BrancHEs.—The branches of the external carotid artery are eight in
number, viz., three directed forwards, the superior thyroid, the lingual,
and the facial ; two directed backwards, the occipital and posterior
auricular ; and three extending upwards, the ascending pharyngeal
branch, together with the temporal and internal maxillary, the two
terminal branches into which the artery divides.

In addition to the principal branches here enumerated, the external
carotid gives off small offsets to the parotid gland.

Varieties.—The peculiarities in the origin of this vessel have been noticed
along with those of the common carotid artery. The branches are not unfre-
quently crowded together on the main stem, near the commencement, or at a
higher point. Occasionally they take origin at regular distances in the whole
length of the vessel. The usual number of branches may be diminished by the
association with another artery of one of the ordinary branches, or by the union
into asingle trunk of two or three branches which are usually derived separately
from the main artery : so also the number may be augmented by the transfer to
this vessel of some branch not ordinarily derived from it, or by the addition of
some unusual branch, There is frequently present a small distinct branch for the
stemo-massoid m1scle, whith bends »utwards over the hypoglossal nerve.

Cr eTid
BRANCHES OF THE EXTERNAL cee ARTERY.

1. Superior Thyroid Artery.—This, the first of the anterior set of
branches, is given off close to the commencement of the external carotid,

362 ARTERIES OF THE HEAD AND NECK.

immediately below the great cornu of the hyoid bone. From this point
the artery curves forwards and downwards to the upper margin of the
thyroid cartilage ; it then descends a short distance beneath the omo-
hyoid, sterno- -hyoid, and sterno-thyroid muscles, furnishing offsets to
those muscles ; and, reaching the anterior surface of the thyroid body,

Fig. 249.—SupurriciaL view or THE ARTERIES or TAB Heap anp Neck (reduced
from Tiedemann). 4

a, orbicularis oris; 6, sterno-mastoid ; c, parotid gland near its duct ; d, body of the
hyoid bone ; e, the clavicle ; 1, trunk of the common carotid artery near its division into
the external and internal carotid arteries: 1’, the internal carotid ; 2, placed on the
upper belly of the omo-hyoid muscle, points to the superior thyroid artery ; 3, lingual
artery and its hyoid branch ; 4, placed on the submaxillary gland at the place where the
facial artery is sunk in the gland, and again where the artery turns over the lower jaw ;
4’, termination of the facial artery by division into the angular and lateral nasal
branches ; 5, submental branch ; 6, inferior labial branches ; 7, transverse facial branch
of the superficial temporal ; 8, superficial temporal, passing over the zygoma and dis-
tributed by 8’, 8’, its anterior and posterior divisions on the surface of the cranium ;
9, occipital artery rising upon the cranium ; 9’, its distribution and anastomosis with the
temporal and posterior auricular arteries; 10, outer part of the subclavian artery ;
11, superficial cervical, and 12, posterior scapular arteries ; 13, suprascapular artery ;
14, acromio-thoracie branches of the axillary artery.

LINGUAL ARTERY. 363

distributes branches to its substance, and communicates freely with the
branches of the inferior thyroid artery.

Branches.— Besides the branches furnished to the muscles which cover it, and
to the thyroid body, together with some to the lowest constrictor of the pharynx,
the superior thyroid furnishes the following offsets, which have received distinc-
tive names :—

(a) The hyoid, a small branch, running transversely inwards immediately below
the os hyoides, and assisting to supply the soft parts connected with that bone.
This little artery sometimes unites, across the middle line, with its fellow from
the opposite side.

(b) A superficial descending or sterno-mastoid branch, which passes downwards
a short distance over the sheath of the large cervical vessels, and ramifies in the
sterno-mastoid and the muscles attached to the thyroid cartilage, as well as in
the platysma and neighbouring integuments. The position of this branch with
respect to the sheath of the carotid artery is the only circumstance which gives
it interest. This branch frequently arises directly from the external carotid.

(¢) The laryngeal branch, or superior laryngeal artery, proceeding inwards in
company with the superior laryngeal nerve, and piercing the thyro-hyoid mem-
brane. Before entering the larynx this branch is covered by the thyro-hyoid
muscle. On reaching the interior of the larynx, it ramifies in the small muscles,
the glands, and the mucous membrane of that organ.

(d) The crico-thyroid, a small branch, to be noticed on foot of its position.
rather than its size. It crosses the membrane connecting the thyroid and cricoid
cartilages, and communicates with a similar branch from the other side : hence
it may be a source of hemorrhage in the operation of laryngotomy.

Varieties.— Sizv.—The superior thyroid artery is frequently much larger, and,
on the other hand, it may be smaller than usual. In either case the deviation
from the accustomed size is accompanied by an opposite alteration in other
thyroid arteries. It has been seen extremely small, ending in branches to the
sterno-mastoid muscle and the larynx. (See the observations on the inferior
thyroid artery.)

Origin —The superior thyroid is often transferred to the upper part of the
common carotid artery ; and it has been seen conjoined with the lingual branch,
or with that and the facial branch of the external carotid.

There are sometimes two superior thyroid arteries.

Branches.—The hyoid branch is frequently very small, or absent. The laryn-
geal branch arises not unfrequently from the external carotid artery, and like-
wise, but rarely, from the common carotid. Examples have occurred of this
branch being of very large size, and terminating in the thyroid body. The
laryngeal artery occasionally enters the larynx through a foramen in the thyroid
cartilage, and it has likewise been observed io pass inwards below the cartilage.

2. Lingual Artery.—The lingual artery arises from the inner
side of the external carotid, between the origins of the superior thyroid
and facial arteries. Curving upwards and inwards, it reaches the upper
margin of the hyoid bone, behind the tip of its oreat cornu ; it then
passes forwards under cover of the hyo-glossus muscle, resting at first
on the middle constrictor of the phary nx, and afterwards on the
genio-hyo-glossus muscle, in contact with which it ascends almost per-
pendicularly to reach the under surface of the tongue, and there makes
its final turn forwards to the tip of that organ, receiving the name of
ranine artery.

At the posterior border of the hyo-glossus muscle, the hypoglossal
nerve crosses the artery, and passes forwards on a lower level, superficial
to the muscle.

Branches.—(a) The hyoid branch runs along the upper border of the hyoid
bone, and supplies the contiguous muscles and skin.

364 ARTERIES OF THE HEAD AND NECK.

(b) The dorsal artery of the tongue, which is often replaced by several smaller
branches. It arises from the deep portion of the lingual artery, beneath the hyo-
glossus muscle, and ascends to supply the upper part, or dorsum, and the substance
of the tongue, ramifying as far back as the epiglottis.

(c) The sublingual branch. Taking origin at the anterior margin of the hyo-
glossus, this branch turns slightly outwards, under cover of the mylo-hyoid
muscle, and between this and the sublingual gland. It supplies the substance of
the gland, and gives branches to the mylo-hyoid and other muscles connected
with the maxillary bone. Small branches are also distributed to the mucous
membrane of the mouth, and the inside of the gums.

(d) The ranine artery, which may be considered from its size and direction the
continuation of the lingual artery. It runs forwards beneath the tongue, giving
numerous branches as it proceeds, covered by the mucous membrane, and
resting on the genio-hyo-glossus muscle. Having reached the tip of the tongue,
it has been said to anastomose with the corresponding artery of the other side ;
but this is denied by Hyrtl. In the last part of its course it lies quite superficially
at the side of the frenum.

Varieties.—The origin of the lingual artery sometimes takes place from a
trunk common to it and the facial artery. It is occasionally joined with the
superior thyroid. The hyoid branch is often deficient ; and it appears that this
branch varies in size inversely with the hyoid branch of the superior thyroid.
The sublingual branch varies in size. It is sometimes derived from the facial
artery, and then perforates the mylo-hyoid muscle. The lingual artery has been
seen to give off as unusual branches, the submental and ascending palatine.

3. Facial Artery.—The facial artery, taking origin a little above
the lingual artery, is first directed obliquely forwards and upwards
beneath the base of the maxillary bone; then changing its direc-
tion, it passes upwards over the base of the lower maxilla, in front
of the masseter muscle. Commencing here its course upon the face,
it is directed forwards, near to the angle of the mouth, and ascends to
the inner canthus of the eye, where it ends by anastomosing .with the
ophthalmic artery. In its whole course the artery is tortuous, a cir-
cumstance connected with the great mobility of the parts on which it
rests.

In the neck, the facial artery, immediately after its origin, which is
comparatively superficial, being covered only by the platysma and fascia,
is crossed by the digastric and stylo-hyoid muscles, and is then con-
cealed in the substance of the submaxillary gland. Emerging from
the gland, it turns over the border of the jaw, covered by the platysma :
here the pulsation of the artery is easily felt, and the circulation through
it may be readily controlled by pressure against the bone. In its pro-
gress over the face, it is covered successively by the platysma and the
zygomatic muscles, and rests upon the buccinator, the levator anguli
oris, and the levator labii superioris.

The facial vein is separated by a considerable interval from the artery
on the face. It takes nearly a straight course upwards, instead of in-
clining forwards near the angle of the mouth, and it is not so tortuous
as the artery.

Branches of the facial nerve cross the vessel; and the infraorbital
nerve is beneath it, separated by the fibres of the elevator of the upper lip.

A, Cervical branches.—The following branches are derived from the facial
artery below the lower jaw :—

(a) The inferior or ascending palatine artery, a branch which ascends between
the stylo-glossus and stylo-pharyngeus muscles, and reaches the pharynx close to
the border of the internal pterygoid muscle. After having given small branches

BRANCHES OF THE FACIAL ARTERY. 365

to the tonsil, the styloid muscles, and the Eustachian tube, this artery divides near
the levator palati muscle into two branches, one of which follows the course
of the circumflexus palati muscle, and is distributed to the soft palate and its
glands, while the other penetrates to the tonsil, and ramifies upon it with the
branch to be next described—The place of this artery upon the palate is often
taken by the ascending pharyngeal.

(4) The tonsillar branch ascends along the side of the pharynx, and penetrating
the superior constrictor of the pharynx, terminates in small vessels upon the
tonsil and the side of the tongue near its root.

(c) The glandular branches, a numerous series which enter the substance of the
submaxillary gland, whilst the facial artery is in contact with it; and some of
which are prolonged upon the side of the tongue.

(d) The submental branch, the largest arising from the facial in the neck.
Leaving the artery near the point at which it turns upwards to the face, it
runs forwards below the base of the maxillary bone on the surface of the mylo-
hyoid muscle and subjacent to the digastric. Giving branches in its course to
the submaxillary gland and the muscles attached to the jaw, and anastomosing
with the sublingual artery, it approaches the symphysis of the chin and divides
into two branches; one of these running more superficially than the other,
passes between the depressor muscle of the lower lip and the skin, supplying
both ; while the other dips between that muscle and the bone, and ramifies in
the substance of the lip, communicating with the inferior labial and mental
branches.

B. Facial branches.—Of the branches derived from the facial artery upon
the side of the face, some are directed outwards to the muscles, as to the masseter
and buccinator, and require only to be indicated. The larger branches are
directed inwards, and are as follows :—

(a) The inferior labial branch. This arises soon after the facial artery has
turned over the lower border of the maxilla, and running forward beneath the
depressor anguli oris, distributes branches to the skin and muscles of the lower
lip, anastomosing with the inferior coronary and submental branches, and with
the inferior dental branch of the internal maxillary artery.

(0) The coronary artery of the lower-lip. Arising near the angle of the mouth,
as often in conjunction with the superior coronary as from the facial separately,
this branch penetrates the muscular fibres surrounding the orifice of the mouth,
takes a transverse and tortuous course between those fibres and the mucous mem-
brane of the lip, and inosculates with the corresponding artery of the opposite
side. Small twigs from it ascend to supply the orbicular and depressor muscles,
the glands, and other structures of the lower lip; whilst others descend towards
the chin, and communicate there with other branches,

(c) The coronary artery of the upper lip. Larger and more tortuous than the
preceding branch, with which it often arises, this vessel runs across between the
muscles and mucous membranes of the upper lip, and inosculates with its fellow
of the opposite side. In addition to supplying the whole thickness of the upper
lip, it gives two or three small branches to the nose, One of these, named the
artery of the septum, runs along the lower border of the septum nasi, on which
it ramifies as far as the point of the nose; another reaches the ala of the nose.

(d) The lateral nasal artery. This branch turns inwards to the side of the
nose beneath the common elevator of the nose and lip, and sends branches to
the ala and the dorsum of the nose. It anastomoses with the nasal branch
of the ophthalmic, with the artery of the septum nasi, and with the infra-
orbital artery.

(e) Angular artery. Under this name is recognised the terminal part of the
facial artery, which inosculates at the inner side of the orbit with a terminal
branch of the ophthalmic artery.

Communication between the superficial and deep branches of the external
cazotid is established by the anastomoses of the facial artery with the infra-
orbital, buccal, inferior dental, and nasal branches of the internal maxillary ;
and between the external and the internal carotids by the anastomosis of the
facial with the ophthalmic arteries,

366 ARTERIES OF THE HEAD AND NECK.

Varieties. — Origin.—The facial artery not unfrequently arises by a common
trunk with the lingual. Occasionally it arises above its usual position, and then
descends beneath the angle of the jaw to assume its ordinary course.

Size—This artery varies much in size, and in the extent to which it is distri-
buted. It has been observed, very rarely, however, to end as the submental, not
reaching the side of the face ; in some cases it supplies the face only as high as
the lower lip. The deficiency of the facial artery is most frequently compen-
sated for by an enlargement of the nasal branches of the ophthalmic at the
inner side of the orbit; occasionally by branches from the transverse facial or
internal maxillary arteries,

Branches.—The ascending palatine artery i is in some instances transferred to
the external’ carotid. This branch varies in size and the extent to which it
reaches. Not unfrequently it is expended without furnishing any branch to the
soft palate. When it is thus reduced in size, the pharyngeal artery takes its
place on the soft palate.

The tonsillar branch is not unfrequently altogether wanting.

The submental branch has been observed to take its rise from the lingual artery.
On the other hand, the facial artery, instead of the lingual, has been found to
furnish the branch which supplies the sublingual gland.

4, Occipital Artery.—The occipital artery, arising from the
posterior part of the external carotid, usually opposite the facial or a
little higher up, is directed upwards and backwards, beneath the pos-
terior bel ly of the digastric muscle, to the interval between the trans-
verse process of the atlas and the mastoid process of the temporal bone.
From that point it turns horizontally backwards along the skull in the
occipital groove of the temporal bone, internal to the mastoid process
and the sterno- mastoid, splenius, digastric and trachelo-mastoid muscles,
and resting on the superior oblique and complexus muscles. Lastly,
changing its direction a second time, and piercing the cranial attach-
ment of the trapezius, it ascends beneath the integument on the back
of the head accompanied by the great occipital nerve, and divides into
numerous branches upon the upper and back part of the cranium.
While in the neck, the occipital artery crosses over the internal carotid
artery, the vagus, and spinal accessory nerves, and the internal jugular
vein ; and the ny orelaes nerve turns from behind over it atits origin.

Branches.—(a) Small muscular offsets to the digastric and stylo-hyoid muscles,
and one of larger size to the sterno-mastoid. This last is so regular a branch that
it is known as the sterno-mastoid branch.

(b) An auricular branch to the back part of the concha of the ear, and two
or three other muscular branches to the splenius and trachelo-mastoid.

(c) The meningcal branch. This runs up with the internal jugular? vein, enters
the skull through the foramen jugulare, and ramifies in the dura mater of the
posterior fossa of the base of the skull.

(d) The cervical branch, ramus cervicalis princeps. To the wpper and back part
of the neck the occipital artery furnishes a branch thus designated. Descending
a short way, this vessel divides into a superficial and a deep branch. The former
ramifies beneath the splenius, sending offsets through that muscle to the trape-
zius ; while the deep branch passes beneath the complexus, and anastomoses with

‘branches of the vertebral artery, and with the deep cervical artery. The size of
this branch varies very much.

(e) The superficial or cranial branches. These pursue a tortuous course between
the integument and the occipito-frontalis muscle ; and in proceeding upwards on
the skull they separate into diverging branches, which communicate with the
branches of the opposite artery, as well as with those of the posterior auricular
artery, and of the temporal artery at the vertex and side of the skull.

Asmall twig, the mastoid branch, enters the skull through the mastoid foramen,
and ramifies in the dura mater,

AURICULAR AND TEMPORAL ARTERIES. 367

Varieties.— Origin —The occipital artery is occasionally derived from the
internal carotid, and from the ascending cervical branch of the inferior thyroid
—an offset of the subclavian artery.

Course.—The occipital artery sometimes passes outside the trachelo-mastoid
instead of internal to it. The chief portion of. the vessel was found, in one in-
stance, to pass over the sterno-mastoid muscle, only a small artery being placed
in the usual position. The artery has,in a few instances, been seen to tum
backwards below the transverse process of the atlas.

Branches.—The posterior auricular and the pharyngeal arteries sometimes take
origin from the occipital.

5. Posterior Auricular Artery.—The posterior auricular artery,
a small vessel, arises from the external carotid a little higher up than
the occipital. It ascends under cover of the parotid gland, and resting
on the styloid process of the temporal bone, reaches the angle formed
by the cartilage of the ear with the mastoid process. It is crossed by
the portio dura of the seventh nerve. Somewhat above the mastoid
portion of the temporal bone it divides into two sets of branches, of
which one set inclines forwards to anastomose with the posterior branch
of the temporal artery, and the other backwards towards the occiput,
on which it communicates with the occipital artery.

Branches.—The following are the branches of this artery :—

(a) Small branches to the parotid gland and the digastric muscle.

(4) The stylo-mastoid branch. This twig enters the foramen of the same name
in the temporal bone ; on reaching the tympanum, it divides into delicate vessels,
which pass, some to the mastoid cells, others to the labyrinth. One branch is
constantly found in young bodies to form, with the tympanic branch of the
internal maxillary artery which enters the fissure of Glaser, a vascular circle
around the auditory meatus, from which delicate offsets ramify upon the mem-
brana tympani, This small tympanic branch sometimes arises from the occipital
artery.

(e) Auricular branches.—As it passes the back of the ear, the auricular artery
gives one or two branches which supply the posterior surface of the concha, and
turn over the margin, or perfor? > the substance of the auricle to gain the ante-
rior surface.

Varieties.—The posterior auricular artery is frequently very small, and has
been seen to end in the stylo-mastoid branch. It is often a branch of the
occipital.

6. Temporal Artery.—The temporal artery, one of the two
branches into which the external carotid artery finally divides a little
below the condyle of the lower jaw, continues upwards in the direction
of the main trunk, whilst the other branch (the internal maxillary)
curves forwards under cover of the jaw. The temporal artery is at
first imbedded in the substance of the parotid gland, in the interval
between the meatus of the ear and the condyle of the lower jaw.
Thence it ascends over the root of the zygoma, against which it may
readily be compressed. From this point onwards, it lies close beneath
the skin, upon the temporal fascia ; and, about two inches above the
zygoma, divides into two branches, which again subdivide and ramify
‘beneath the integument on the side and upper part of the head.

Branches.—Besides several small offsets to the parotid gland, some branches
to the articulation of the lower jaw, and one or two to the masseter muscle, the
temporal artery gives off the following branches :

(a) The transverse artery of the face. This branch arises whilst the temporal

368 ARTERIES OF THE HEAD AND NECK.

Fig. 250.

Fig. 250.—Drep Virw or THE Carotip, SuschavianN, AND AXILLARY ARTERIES (from

Tiedemann.) 4}

The great pectoral, the sterno-mastoid, and the sterno-hyoid and sterno-thyroid muscles
have been removed ; the front part of the deltoid has been divided near the clavicle ; the
greater part of the digastric muscle has been removed, and the upper part of the splenius
capitis and trachelo-mastoid divided near the mastoid process. For the explanation of
the references from 1 to 12, see p. 396. Carotid Artery and its Branches.—138, lower
part, and 14, upper part of the right common carotid artery; 15, trunk of the

TEMPORAL ARTERY. 369

external carotid artery ; 16, trunk of the internal carotid artery ; 17, 17, inside the
thyroid axis of the subclavian artery, and on the inferior thyroid artery where it is
distributed in the gland; 18, superior thyroid artery, anastomosing in the gland with
the inferior thyroid ; 19, lingual artery, brought into view by the removal of the lower
part of the hyo-glossus muscle ; 20, facial artery, giving off the palatine, tonsillitic
and submental; 21, inferior labial ; 22, coronary artery ; 23, occipital artery ; 24, pos-
terior auricular artery ; 25, superficial temporal artery ; 26, internal maxillary artery ;
27, transverse facial, given off in this instance directly by the external carotid
artery. :

artery is deeply seated in the parotid gland, through the substance of which it
runs nearly horizontally forwards ; getting between the parotid duct and the
zygoma, it rests on the masseter muscle, and is accompanied by one or two
transverse branches of the facial nerve. It gives small vessels to the parotid
gland, the masseter muscle, and the neighbouring integument ; and divides into
three or four branches, which are distributed to the side of the face, anasto-
mosing with the infra-orbital and facial arteries.

(2) The middle temporal branch. This arises close above the zygoma, and
immediately perforating the temporal fascia, sends branches to the temporal
muscle, which communicate with the deep temporal branches of the internal
maxillary artery. An offset from this artery runs to the outer angle of the
orbit, where it gives branches to the orbicularis palpebrarum muscle.

(c) The anterior auricular branches, two or more in number, superior and
inferior. These branches arise above the middle temporal. They are distributed
to the fore-part of the pinna, the lobe of the ear, and a part of the external
meatus, anastomosing with the ramifications of the posterior auricular artery.

(d) The anterior temporal branch, one of the two terminal branches of the
temporal artery. This vessel inclines forwards as it ascends over the temporal
fascia, and ramifies extensively upon the forehead, supplying the orbicular and
occipito-frontal muscles, the pericranium, and the skin, and communicating with
the supra-orbital and frontal branches of the ophthalmic artery. On the upper
part of the cranium the branches of this artery are directed from before back-
wards. When it is desired to take blood from the temporal artery, the anterior
temporal branch is selected for the operation.

(e) The posterior temporal branch. This is usually larger than the anterior,
passes back on the side of the head, above the ear, and over the temporal fascia;
its branches ramify freely in the coverings of the cranium, both upwards to the
vertex, where they communicate with the corresponding vessel of the oppcsite
side, and backwards to join with the occipital and posterior auricular arteries.

Varieties.—The temporal artery is frequently tortuous, especially in aged
persons. Occasionally a large unusual branch runs forward above the zygoma,
to the upper part of the orbit. The temporal artery sometimes joins with the
ophthalmic and furnishes large frontal arteries.

The anterior temporal branch is sometimes larger than the posterior, and
passing backwards over the vertex of the head, communicates with the occipital.

The transverse artery of the face varies in size ; occasionally it is much larger
than usual, and takes the place of a defective facial artery. In some instances
the transverse artery arises directly from the external carotid.

7. Internal Maxillary Artery.—The internal maxillary or deep
facial artery, the larger of the two terminal branches of the externa!
carotid, is concealed by the parotid gland at its origin below the con-
dyle of the jaw; it curves horizontally forwards between the jaw and
the internal laterai ligament of the temporo-maxillary joint, then passes
obliquely forwards and upwards on the outer surface of the external
pterygoid muscle (not unfrequently beneath and within it), and opposite
the interval between the two heads of that muscle, bends inwards to the

spheno-maxillary fossa, where it ends by division into a number of
branches.
VOL, I. BB

370 ARTERIES OF THE HEAD AND NECK.

To facilitate the arrangement of its numerous branches, this artery
may be considered in three parts, viz.: 1, the part between the jaw
and internal lateral ligament; 2, the part in contact with the external
pterygoid muscle ; and, 3, the part in the spheno-maxillary fossa.

A. Branches of the first part.—The branches of the first part of the artery
all pass through the bony foramina.

(a) The tympanic branch, of small size and variable in origin, passes deeply
behind the articulation of the lower jaw, and enters the fissure of Glaser, sup-
plying the laxator tympani muscle, and the tympanic cavity, where it ramifies

Fig. 251.—Drxrpr Dissection or THE Hap Anp Facs, To sHow THE INTEPNAL
Maxintary ARTERY AND ITs BrancHes (from Tiedemann). 3}

The right half of the calvarium, the zygomatic arch, and the upper half of the ramus
of the lower jaw, with the external pterygoid muscle, have been removed ; some of the
superficial muscles of the face have been divided, and the internal pterygoid and
buccinator muscles are exposed: 1, facial artery, rising over the edge of the lower
jaw ; 2, inferior labial branches ; 2’, deep mental branch of the inferior dental artery ;
3, facial artery continued ; 4, superior coronary of the facial ; 5, lateral nasal ; 6, frontal
branch of the ophthalmic artery, giving descending twigs to communicate with the angular
branch of the facial and with the dorsal nasal; 7, internal carotid artery ; 8, external
carotid artery at the place where it passes through the parotid gland, which has been
removed ; 9, division of the external carotid artery into superficial, temporal and internal
maxillary arteries ; 10, superficial temporal ; 11, masseteric branch of the external carotid
artery ; 12, the trunk of the internal maxillary artery, at the origin of its inferior dental
branch ; 13, on the root of the zygoma, points to the middle meningeal branch, and on
the dura mater above, to its distribution; 14, on the lower part of the temporal
muscle separated from the coronoid process of the jaw, is between the deep temporal
branches of the artery; 15, pterygoid branches; 16, buccal artery ; 17, posterior
superior dental, and deepest part of the internal maxillary artery where it enters the
spheno-maxillary fossa ; 18, branches of the infraorbital artery issuing upon the face.

INTERNAL MAXILLARY ARTERY, 371

upon the membrana tympani. It anastomoses in the tympanum with the stylo-
mastoid and Vidian arteries.

(6) The middie or great meningeal artery, by far the largest of the arteries
which supply the dura mater, passes directly upwards under cover of the external
pterygoid muscle, between the two roots of the auriculo-temporal nerve, and
enters the skull by the spinous foramen of the sphenoid bone. Within the
cranium, it ascends to the anterior inferior angle of the parietal bone, and divMes
into numerous branches, which ramify in deep arborescent grooves on the inner
surface of the bones some passing upwards over the parietal bone, as high as
the vertex, and others backwards even to the occipital bone.

Immediately on entering the cranium the meningeal artery gives minute
branches to the ganglion of the fifth nerve and to the dura mater near the sella
turcica, and a small twig which enters the hiatus Fallopii, and anastomoses with
the stylo-mastoid branch of the posterior auricular artery. It also inosculates
with branches of the ophthalmic artery.

The middle meningeal artery is accompanied by two veins.

(¢) The small meningeal artery, usually arising from the preceding branch,
enters the skull through the foramen ovale, to supply the dura mater in the
middle fossa.

(d) The inferior dental artery, passing downwards, enters the dental canal
along with the inferior dental nerve, and subsequently escapes on the face by the
mental foramen. As it enters the canal, it gives off the mylo-hyoid branch,
which, with the nerve bearing the same name, runs in a groove on the inner
surface of the jaw, below the dental foramen, and ramifies on the under surface
of the mylo-hyoid muscle. In its course through the bone, the inferior dental
artery gives off small offsets, which ascend to enter the minute apertures in the
extremities of the fangs of the teeth, and supply the pulp of each; before
emerging at the mental foramen, it sends forwards a branch which supplies the
incisor teeth and inosculates with its fellow of the opposite side. The terminal
or facial branches anastomose with the inferior coronary and submental arteries.

B.— Branches of the second part.—The branches of this part are chiefly
distributed to muscles.

(a) The deep temporal branches, two in number (anterior and posterior),
ascending between the temporal muscle and the cranium, supply that muscle,
and anastomose with the branches of the other temporal arteries, and with
minute branches of the lachrymal artery, through small foramina in the malar
hone.

(4) The pterygoid branches, small, short offsets, irregular in number and origin,
are distributed to the pterygoid muscles.

(ec) The masseteric is a small but regular branch which passes from within
outwards, above the sigmoid notch of the lower maxillary bone, to the deep
surface of the masseter muscle. It is often joined at its origin with the posterior
temporal branch.

(d) The buccal branch runs obliquely forwards upon the buccinator muscle
with the buccal nerve; it is distributed to that and other muscles of the cheek,
and anastomoses with the branches of the facial artery.

C.—Branches of the third part.—These branches, like those of the first
series, enter bony foramina or canals,

(a) The alvcolar or superior maxillary branch, arising near the tuberosity of
the maxillary bone, frequently in common with the infra-orbital branch, runs
tortuously forwards upon the surface of the upper jaw, and gives off the superior
dental and other branches which enter the foramina of the tuberosity, and supply
the pulps of the upper molar and bicuspid teeth, besides ramifying in the lining
membrane of the maxillary sinus. Other small branches supply the gums.

(4) The infra-orbital artery runs horizontally forwards into the infra-orbital
canal, and having traversed that canal along with the superior maxillary nerve,
emerges upon the face at the infra-orbital foramen.

Whilst still in the canal, it sends upwards into the orbit small branches, which
enter the inferior rectus and the inferior oblique muscles of the eye and the lach-
rymal gland, and others downwards to supply the front feeth. On the face it

BB 2

372 ARTERIES OF THE HEAD AND NECK.

gives branches upwards, to the lachrymal sac and inner angle of the orbit, anas-
tomosing with the nasal branches of the ophthalmic and facial arteries, and
sends other branches downwards, beneath the levator labii superioris, which join
the ramifications of the transverse facial, buccal, and superior coronary arteries.
(c) The descending or superior palatine artery descends perpendicularly through.

Fig, 252.

Fig. 252.—Deep View or THE Linevan anp Puaryneran Arrentes (from R. Quain). 4%

The lower jaw has been removed, and the tongue drawn forwards between the teeth ;
the external pterygoid muscle has been removed, and the temporal muscle has been turned
up from within the zygoma; a, the root of the zygoma, above the glenoid cavity ;
b, placed on the lobe of the ear, points by a line to the styloid process, from which the:
stylo-glossus and stylo-pharyngeus are seen passing downwards and forwards, and the
stylo-hyoid detached from the hyoid bone is thrown backwards with the digastric muscle ;
c, transverse process of the atlas ; d, upper surface of the tongue ; e, sawn surface of
the symphysis of the lower jaw ; f, the angle of the hyoid bone ; 1, left common carotid
artery ; 2, internal carotid artery ; 3, external carotid artery ; 3’, placed on the stylo-
pharyngeus muscle, points by a line to the upper part of the external carotid artery
divided where it enters the parotid gland ; 4, superior thyroid artery, its laryngeal branch
passing upon the thyro-hyoid membrane; 5, lingual artery about to pass within the
hyo-glossus muscle ; 5’, placed on the genio-hyo-glossus, points to the continuation of the
lingual artery as the ranine ; 6, the trunk of the facial artery cut short ; 6’, its tonsilar
and pharyngeal branches ; 7, occipital artery cut short ; 8, ascending pharyngeal artery ;
8’, its upper part turning down upon the pharynx ; 9, internal maxillary artery as it
passes into the spheno-maxillary fossa, and gives the posterior dental and the infra-
orbital arteries ; 9’, middle meningeal artery ; 10, placed on the deep surface of the
temporal muscle, which is turned up and shows some cut branches of the deep temporal
arteries.

ASCENDING PHARYNGEAL ARTERY. O73

the posterior palatine canal, with the palatine nerve, and runs along the hard
palate. In front it ends in a small vessel which ascends through the incisor
foramen, and anastomoses with the artery of the septum. While descending in
the canal, this artery sends off twigs through the bone, which communicate on
the soft palate with the ascending palatine branch of the facial artery.

(d) The Vidian branch traverses the Vidian canal with the nerve of the same
name; it is distributed to the Eustachian tube and the top of the pharynx, and
sends a small vessel into the tympanum.

(ce) The pterygo-palatine, a very small branch, passes backwards through the
pterygo-palatine canal to reach the top of the pharynx, to which, and to the
Eustachian tube and sphenoidal cells, it is distributed.

(f) The nasal or spheno-palatine artery enters the spheno-palatine foramen, and
divides into two or three branches, some of which may ramify extensively over
the spongy bones, while others supply the posterior ethmoidal cells and the
‘antrum. One long branch, the artery of the scptum, rans forwards along the
septum nasi, ends in a small vessel which enters the incisor foramen, and inoscu-
dates with the descending palatine artery.

Varieties. — Origin.—The internal maxillary artery is very constant in its place
of origin. It has, however, been seen to arise from the facial.

Course.—The artery often passes under cover of the external pterygoid muscle,
crossing the inferior maxillary division of the fifth nerve. It has likewise been
observed to issue from under cover of the external pterygoid by piercing the
middle of that muscle. When the artery is placed beneath the muscle, it has
been found lodged in a notch in the posterior margin of the external pterygoid
‘plate, and bound down by fibrous structure.

Branches.—The middle meningeal artery occasionally furnishes the lachrymal
artery (usually an offset of the ophthalmic), it has also been seen to give off the
ophthalmic itself, and on the other hand the ophthalmic has been seen to give off
the middle meningeal, peculiarities which may be looked on as resulting from
the enlargement of an ordinary anastomosing branch. (Curnow, Journ. of Anat.,
vol. viii., p. 155. Krause. Blandin.)

In a case in which the internal carotid artery was wanting, two tortuous
branches from the internal maxillary entered the skull by the foramen rotundum
and foramen ovale, to supply its place. (Quain, “On the Arteries,’ p. 15,
fig. 8.)

8. Ascending Pharyngeal Artery.—This artery, long and slender,
‘the smallest branch of the external carotid which has received a distinc-
tive designation, arises most commonly from half an inch to an inch

above the origin of the external carotid; and in its straight course

upwards rests on the rectus capitis anticus, close to the surface of the
pharynx, between it and the internal carotid artery, and is thus directed
up towards the base of the skull.

Branches.—These are very small, and may be divided into three sets, viz.,
those to the pharynx ; a set directed outwards ; and meningeal branches.

(a) The pharyngeal branches pass inwards, for the most part to the pharynx.
One or two small and variable branches ramify in the middle and inferior con-
strictor muscles. Higher up than these is a larger and more regular branch,
which runs upon the upper constrictor, and sends small ramifications to the Eus-
tachian tube, and to the soft palate and tonsil.

The last mentioned, or palatine branch, is sometimes of considerable size, and
supplies the soft palate, taking the place of the inferior palatine branch of the
facial artery, which in such cases is small. It divides into an anterior and a
posterior twig, both of which anastomose with their fellows of the opposite side
in the middle line.

(b) The external branches, small and irregular, are distributed to the rectus
anticus muscle, the first cervical ganglion of the sympathetic nerve, some of the
cerebral nerves as they issue from the skull, and to lymphatic glands. Some

374 ARTERIES OF THE HEAD AND NECK.

of them anastomose with the ascending cervical branch of the subclavian

artery.
(c) The meningeal branches are terminal twigs, which pass through the
foramen lacerum posticum and anterior condylar foramen, to end in the dura

mater.

Varieties.—This artery varies greatly in its place of origin from the carotid.
It occasionally springs from the occipital or internal carotid, and, in a few
instances, it has been seen double.

INTERNAL CAROTID ARTERY.

The internal carotid artery is distributed to the brain, to the eye
with its appendages, and in part to the forehead. It extends directly
upwards from the termination of the common carotid artery, opposite
the upper border of the thyroid cartilage, to the carotid foramen of the
temporal bone. Entering the cranial cavity through the carotid canal,
it crosses the foramen lacerum medium, and turning upwards on the
side of the sphenoid bone, it passes forward on the carotid groove of
that bone. ‘Thence it turns abruptly upwards on the inner side of the
anterior clinoid process, and divides opposite the inner end of the
Sylvian fissure of the brain, into the anterior and middle cercbral
arteries.

In the neck, the internal carotid artery varies in length according to
the height of the division of the common carotid. It rests on the
rectus anticus major muscle, and has the pharynx and tonsil on its
inner side. The internal jugular vein is in contact with it as far as
the base of the skull, lying on its superficial and posterior aspect : and.
placed more deeply behind it are the vagus nerve and main trunk of
the sympathetic. At its commencement the artery is covered only by
the sterno-mastoid muscle, by the platysma myoides, and by fascia, and
lies to the outer side of the external carotid. It soon, however, becomes
concealed by the parotid gland, and lies internal and posterior to the
external carotid trunk, and is crossed first by the occipital artery, and
by the hypoglossal nerve and the digastric and stylo-hyoid muscles,
three structures which lie superficial to both carotid arteries; and
higher up, by the stylo-glossus and stylo-pharyngeus muscles, and the
glosso-pharyngeal nerve, which, together with, in some cases, the pha-
ryngeal branch of the vagus nerve, pass forwards between the external
and internal carotid arteries.

Within the cranium, the internal carotid artery has a very tortuous
course, curving forwards and inwards within the carotid canal, then
turning upwards to reach the sphenoid bone, on which it is at first
directed horizontally forwards, and afterwards resumes the vertical
position on the inner side of the anterior clinoid process. In this
part of its course the artery is accompanied by the carotid and caver-
nous plexuses of the sympathetic nerve. After leaving the carotid
canal, it lies in the floor of the cavernous sinus, and in contact with it
externally are the nerves which pass through the sphenoidal fissure.
Opposite the anterior clinoid process it pierces the layer of dura mater
which forms the roof of the sinus, and becomes invested with arachnoid
membrane.

Varieties.—In very rare cases of abnormal arrangement of the arch of
the aorta, the internal carotid artery has arisen as a primary trunk, A few
examples of its entire absence are recorded,

St

OPHTHALMIC ARTERY, 37

BRANCHES OF THE INTERNAL CAROTID ARTERY

In the neck the internal carotid artery gives usually no branch.
While within the carotid canal it sends a small offset to the tympanum,
which anastomoses with the tympanic and stylo-mastoid arteries.
Within the cavernous sinus some small branches proceed from it to
supply the walls of the sinus and the adjacent dura mater.

Opposite the anterior clinoid process, the internal carotid gives off the
ophthalmic artery; and at the Sylvian fissure of the brain, before
dividing into the anterior and middle cerebral arteries, it gives off or is
joined by the posterior communicating artery, a slender anastomotic
branch which unites the internal carotid with the posterior cerebral
branch of the basilar artery.

1. Ophthalmic Artery.—This artery, arising from the internal
carotid artery by the side of the anterior clinoid process, enters the
orbit by the foramen opticum, below and to the outer side of the optic
nerve. It soon changes its direction, passing over the nerve to reach
the inner wall of the orbit, along which it runs forwards, and terminates
in branches which ramify on the forehead and side of the nose.

Branches.—(a) The ee tery, arising on the outer side of the optic
nerve, passes forwards along the upper border of the external rectus muscle to
the lachrymal gland, in which the greater number of its branches are distributed.
Some of the branches pass onwards to the eyelids and conjunctiva, joining with
other palpebral branches; and one or two delicate malar branches pierce the
malar bone and reach the temporal fossa, where they join branches from the deep
temporal arteries. The lachrymal artery has also branches of communication
through the sphenoidal fissure with small offsets from the middle meningeal
artery,

(b) The central artery of the retina, avery small vessel, pierces the sheath and
substance of the optic nerve about a quarter of an inch behind its junction with
the eyeball, and runs imbedded within it to the retina, in which it ramifies in
minute branches. In the fcetus, a very delicate vessel passes forwards through
the vitreous humour, to reach the posterior surface of the capsule of the crystal-
line lens.

‘(c) The supraorbital branch ascends above the muscles, and coursing forwards
to the supraorbital notch, in company with the frontal nerve, terminates on the
forehead. It distributes branches to the eyelids, and communicates with the
temporal artery.

(d) The ciliary arteries are divisible into three sets, viz., short, long, and
anterior ciliary. The short ciliary arteries, varying from twelve to fifteen in
number, enclose the optic nerve as they pass forwards to reach the posterior
aspect of the sclerotic coat, which they pierce, and enter the eyeball about a line
or two from the entrance of the optic nerve. The Jong ciliary arteries, two in
number, also enter the back of the eyeball, and then pass forwards, one on each
side, between the choroid and sclerotic coats, as far as the ciliary ligament, where
they divide into branches. The anterior ciliary arteries are derived from some of
the muscular branches; they form a vascular circle around the fore part of the
eyeball, and then pierce the sclerotic within a line or two of the margin of the
cornea, All these ciliary arteries anastomose together within the eyeball, their
distribution in which will be particularly described with the anatomy of the
eyeball.

(¢) The muscular branches, subject to much variety, usually arranged in an
upper and lower set, supply the muscles of the orbit.

(f) The cthmoidal branches are two in number, a posterior and an anterior.
They pass through the posterior and anterior internal orbital foramina, the
latter in company with the nasal branch of the ophthalmic nerve ; and both

376 ARTERIES OF THE HEAD AND NECK.

arteries having furnished branches to the ethmoidal cells, enter the skull, supply
the adjacent dura mater, and send branches through the cribriform lamella to
the nose.

Fig. 253.

Fig. 253.—SrMmraGRAMMATIC VIEW OF THE ARTERIES OF THE ORBIT AND NEIGHBOUR-
ING PARTS, WITH THEIR BRANCHES AND ANASTOMOSES (founded on Hirschfeld and
Leveillé, with additions). (A. T.)

The outer wall of the orbit has been removed, the sinus maxillaris is laid open, the
eyelids are turned forwards, and the external and superior recti, and the superior oblique
muscles have been partially removed. a, optic nerve; 6, hook, holding up the posterior
part of the superior rectus muscle, the anterior part of which is left attached to the
eyeball ; ec, lachrymal gland, thrown up on the frontal bone ; d, insertion of the inferior
oblique muscle ; e, inferior rectus ; f, f, anterior and posterior portions of the divided
external rectus ; g, maxillary sinus ; 4, hook, holding up the eyelids, of which the deep
surface is exhibited.

I, internal carotid artery below the inferior aperture of the carotid canal of the
temporal bone, which is indicated higher up by a ring surrounding the artery; 1’, the
part of the artery situated within the temporal bone, a second ring indicating the place
of the upper aperture of the temporal canal ; 1”, the part of the artery situated on the
sphenoid bone ; upon this artery, 1, twig to the mastoid cells and tympanum ; 2, twigs
in the cavernous sinus ; 8, communicating branches to the posterior cerebral ; 4, middle
cerebral ; 5, anterior cerebral. .

II, basilar artery ; upon this artery, 6, posterior cerebral ; 7, superior cerebellar : the
accented numbers, 3’, 4’, 5’, 6’, 7’, indicate, on the left side, the arteries already named
under the same numbers on the right side, and with these and the anterior communicating
branch marked by +, complete the Circle of Willis.

III, upper part of the external carotid artery dividing into III x, the superficial
temporal, and III’, III’, the internal maxillary artery ; upon the latter artery, 1, inferior
dental branch ; 2, middle meningeal ; 3, 3, masseteric and pterygoid branches ; 4, buccal ;
5, 5, anterior and posterior deep temporal ; 6, posterior superior dental ; 7, infraorbital ;
7’, branches of the same issuing upon the face; 8, part of the internal maxillary, which
passes into the spheno-maxillary fossa.

IV, facial artery, terminating at 11, in the angular, and giving off, at 12, the lateral
nasal branches, and others which communicate with the infraorbital.

In the orbit the following numbers indicate the ophthalmic artery and its branches : 1,

CEREBRAL ARTERIES. 317

the ophthalmic artery at its origin from the internal carotid ; 1’, the same artery con-
tinued on the upper and inner side of the orbit ; 2, lachrymal branch ; 3, central artery
of the retina ; 4, some of the ciliary arteries ; 5, 5, upper and lower muscular branches ;
6, supraorbital ; 7, 7’, posterior and anterior ethmoidal arteries ; 8, palpebral ; 8’, 8”,
its superior and inferior divisions; 9, frontal; 10, nasal, communicating with the
angular of the facial.

(yg) The two palpebral branches, superior and inferior, arise near the front of
the orbit, usually together, but soon diverge, one lying above, the other below
the tendon of the orbicularis muscle at the inner angle of the eye ; they form
arches, one in each lid, which le between the orbicularis muscle and tarsal car-
tilage, and send branches to the caruncula lachrymalis and the lachrymal sac.

(h) The nasal branch courses forwards above the tendon of the orbicularis
muscle to the root of the nose, where it ramifies, maintaining a free communi-
cation with the nasal and angular branches of the facial artery.

(i) The frontal branch runs close to the preceding, but on reaching the margin
of the orbit turns upwards on the forehead, where it anastomoses with the supra-
orbital artery.

2. Cerebral Arteries.—The terminal branches of the internal

Fig. 254.—View oF THE
DISTRIBUTION OF THE
BRANCHES OF THE IN-
TERNAL CAROTID AND
VERTEBRAL ARTERIES TO
THE LOWER PARTS OF
THE Brain (altered
from Hirschfeld and
Leveillé), (A.T.) 4

On the left side of the
brain a portion of the
middle lobe of the cere-
brum has been removed so
as to open up the fissure of
Sylvius and expose the
convolutions of the island
of Reil ; and the left half
of the cerebellum has been
removed to show the lower
surface of the posterior
cerebral lobe. 1, placed
on the optic commissure,
points to the divided stem
of the left internal carotid
artery where its cerebral
distribution begins ; 2,
anterior cerebral branch,
exposed fully by the re-
moval of a portion of the
left optic nerve ; 2’, placed
on the knee or anterior
bend of the corpus callo-
sum between its two arteries ; x, placed on the lamina cinerea in front of the optic
commissure, marks the anterior communicating artery; 3, middle cerebral artery,
passing into the fissure of Sylvius and distributing its branches over the convolutions of
the island of Reil and others beyond; 4, placed between the infundibulum and the
corpora albicantia, points by a line to the left posterior communicating artery ; 5, basilar
artery ; 6, posterior cerebral artery, its distribution exposed on the left side by the
removal of half of the cerebellum ; 7, placed on the pons Varolii, points to the right
superior cerebellar artery ; 8, anterior inferior cerebellar artery ; between 7, and 8, one
of the largest of the transverse branches of the basilar artery ; 9, 9, right and left
vertebral arteries ; 10, posterior inferior cerebellar arteries ; 11, anterior spinal arteries.

378 ARTERIES OF THE HEAD AND NECK.

carotid artery supply the anterior and greater part of the pia mater and
brain.

The anterior cerebral, comm acing at the subdivision of the in-
ternal carotid at the inner end of the fissure of Sylvius, turns forwards
towards the middle line to reach the longitudinal fissure between the
anterior lobes of the cerebral hemisphere, and is connected with the
vessel of the opposite side by the anterior communicating artery, a
branch not more than two lines in length. The two anterior cerebral
arteries, lying close together, in the next place turn round the anterior
border of the corpus callosum, run backwards on its upper surface,
concealed by the cerebral hemispheres, and end by anastomosing with
the posterior cerebral arteries. In their course they give numerous
branches to the olfactory lobes and optic nerves, the under surface of
the anterior lobes, the thind ventricles, corpus callosum and inner
surface of the hemisphere.

The middle cerebral artery, larger than the anterior, inclines ob-
liquely outwards, taking the course of the fissure of Sylvius ; within
this it divides into several branches, which ramify in the pia mater
investing the surfaces of the anterior and middle lobes of the brain,
and join 1 with the branches of both the anterior and posterior cerebral
arteries. Numerous small branches, without ramifying in the pia
mater, turn upwards at once, and enter the brain at the anterior per-
forated spot, through which they reach the corpus striatum.

One or two choroid arteries, which sometimes arise directly from the
internal carotid, passing backwards, enter the fissure between the middle
lobe and the crus cerebri, to reach the descending cornu of the lateral
ventricle, in which they are distributed to the choroid plexus.

Varieties.—In rare instances, the anterior cerebral arteries have united into a
single trunk, like the basilar artery behind, and have again divided into a right
and left artery. The anterior communicating artery is frequently double.

Frequently the posterior cerebral artery of one side arises by an enlarged pos-
terior communicating artery from the internal carotid, and is connected only by
a slender vessel with the basilar.

Circle of Willis.—A remarkable anastomosis exists between the
branches of the vertebral and internal carotid arteries within the
cranium, by which the circulation in the brain may be equalised, and
any irregular ity which might arise from the obliter ation of one, or even
two of the vessels, may speedily be remedied by a corresponding en-
largement of the others. This anastomosis, known as the circle of
Wilhs, results from a series of communications between the following
branches. The anterior cerebral arteries are connected together, as
already mentioned, in the longitudinal fissure by the anterior commu-
nicating artery. The right and left internal carotids, the trunks
from which the anterior cerebral arteries arise, are united by the pos-
terior communicating arteries to the posterior cerebral arteries, which
arise behind from a single trunk—the basilar artery. Within or
opposite to the area of this vascular circle are the following parts of
the encephalon, viz., the commissure of the optic nerves, lamina cinerea,
infundibulum and tuber cinereum, corpora albicantia, posterior per-
forated spot with part of the crura cerebri, and the origin of the third
pair of nerves.

Distribution of the Arteries in the Cerebrum.—The recent researches
of Duret and Heubner have thrown some additional light on the circulation in

DISTRIBUTION OF VESSELS IN THE BRAIN. 379

the brain. According to these authors, the three great arteries which go to the
cerebrum—the anterior, middle, and posterior cerebral—give origin to two very
distinct systems of vessels. The first of these, consisting of branches given
off by the arteries immediately after they leave the circle of Willis, is destined
to the great central ganglia, and is called the central system of arteries ; the
other ramifies in the pia mater, and is distributed to the grey matter of the con-
volutions and the subjacent white matter; it is called the cortical system of
arterics, These two systems are to a great extent independent of each other,
the vessels which connect them being few in number, and of almost capillary
minuteness. Moreover, not only are the two systems thus distinct, but the
branches of the several arteries are also limited in their distribution to certain
well-defined areas, and their communications are few and small, and occur only
at the periphery of their respective areas of distribution, so as to render the areas
practically independent territories. The same remark applies, in less degree,
however, to the secondary, and even tertiary division of these arteries.

The anterior cerebral has a very limited central distribution, giving only a few
small branches (and these liable to much variation as to size and number) to the
anterior extremity of the corpus striatum. Its cortical branches are three in
number : the first being distributed to the two internal orbital convolutions ;
the second to the anterior extremity of the marginal convolution, to the superior,
and to the anterior portion of the middle frontal convolutions on the outer sur-
face ; the third to the inner surface of the hemisphere as far as the extremity of
the calloso-marginal fissure ; the fourth to the quadrate lobule; and from this
last branch the artery of the corpus callosum is given off.

The middle cerebral immediately after leaving the internal carotid gives off a
number of small vessels which pass directly upwards, parallel to each other, into
the foramina of the anterior perforated space, and enter the base of the corpus
striatum. They are distributed to the two extraventricular nuclei (grey nucleus
and lenticular nucleus) of that body, to the posterior part of the nucleus candatus
and the portion which borders upon the optic thalamus. The main trunk of the
middle cerebral passes upwards and outwards in the fissure of Sylvius until it
reaches the island of Reil, on the surface of which it divides into four branches.
The first branch is limited in its distribution to the outer part of the orbital
surface and the adjacent inferior frontal convolution ; the second branch sup-
plies the posterior part of the middle frontal, and the chief part of the ascending
frontal convolution ; the third branch passes in the fissure of Rolando to the
rest of the ascending frontal and to the ascending parietal convolution and to
the anterior part of the superior parietal lobule; and the fourth, lying in the
posterior branch of the fissure of Sylvius, supplies the inferior parietal lobule,
and the superior temporo-sphenoidal convolution.

The posterior cerebral arteries (the origin and course of which are described
at p. 386) gives off a number of twigs in the posterior perforated spot, and
others as it passes round the crus, both of which sets pass into the thalami optici,
crura cerebri and corpora quadrigemina. The cortical branches are three in
number: the first is distributed to the anterior part of the uncinate gyrus and
its immediate vicinity ; the second branch supplies the posterior part of the
uncinate gyrus and the lower part of the temporo-sphenoidal lobe; the third,
lying in the calcarine fissure, supplies the occipital lobe on its inner and outer
surfaces. (H. Duret, in Archives de Physiol. 1874; Heubner, in Centralblatt fiir
die Med. Wissensch. 1872.)

SUBCLAVIAN ARTERIES.

The subclavian artery is only the commencing portion of a long
trunk which forms the main artery of the upper limb, and which is
artificially divided for purposes of description into three parts, named
the subclavian, axillary, and brachial arteries.

The subclavian artery, arising on the right side from the extremity
of the innominate stem, and on the left from the arch of the aorta,
yasses a short way up into the neck, arches outwards over the pleura.

/

380 THE SUBCLAVIAN ARTERY.

and rests between the scalenus anticus and scalenus medius muscles on
the first rib. At the outer border of the first rib it ceases to be called
subclavian, and is continued into the axillary artery.

Each subclavian artery is conveniently divided into three parts,—the
jirst part extending from the origin of the vessel to the inner border of
the anterior scalenus muscle ; the second consisting of the portion of the
vessel situated behind that muscle ; and the third reaching outwards
to the external border of the first rib. In examining each of these
portions in detail, it will be necessary in the first part to give separate
descriptions for the right and the left sides, as there is a material
difference in the origin, course, and relations of the two vessels.

THE FIRST PART OF THE RIGHT SUBCLAVIAN ARTERY commences close
to the trachea, at the division of the innominate artery, behind the upper
part of the sterno-clavicular articulation, and ends at the inner margin
of the anterior scalenus muscle. Separating from the carotid artery, it
arches upwards and outwards, and ascends above the level of the clavicle
to an extent which varies in different cases. It is deeply placed, being
covered by the platysma, the sterno-mastoid, the sterno-hyoid, and
sterno-thyroid muscles, and the deep cervical fascia. It is in contact
with the pleura inferiorly, and is separated by an interval from the
longus colli muscle behind.

Relation to Veins—The subclavian vein lies lower than the artery,
close under the clavicle. In its course to join this vein, the eterna/
jugular passes in front of the artery near the scalenus muscle, as do
also, nearer the middle line, the anterior jugular and vertebral veins.

Relation to Nerves.—The vagus nerve passes in front of the artery
on the inner side of the internal jugular vein, and its recurrent laryngeal
branch, turning round below the artery, ascends behind. Some cardiac
branches of the sympathetic nerve pass down over the artery, while the
main trunk passes behind.

THE FIRST PART OF THE LEFT SUBCLAVIAN ARTERY arises from the
upper surface of the arch of the aorta, at the left end of its transverse
portion, and ascends to the margin of the first rib, behind the insertion
of the anterior scalenus muscle. It is, therefore, longer than the first
part of the right subclavian, and ascends at first almost vertically out
of the chest, instead of arching, like that vessel, outwards across the
neck. It is at first overlapped by the left lung, and is covered in front
and on the left side by the pleura; it rests on the longus colli muscle,
and lies, for a short space, in front of the cesophagus (here deviating to
the left side), and the thoracic duct. 'To the inner or right side of the
vessel are situated the left carotid artery and the trachea, and further
up the cesophagus and the thoracic duct.

Relation to Veins.—The internal jugular vein is immediately before
the artery, where it turns outwards from the thorax, close to the scalenus
muscle ; and the left innominate vein is likewise anterior to it.

Relation to Nerves.—The pneumogastric nerve is anterior to the first
part of the left subclavian artery, and parallel with it, the recurrent
branch on this side turning round below the arch of the aorta. The
phrenic nerve descends over the artery along the inner margin of the
scalenus muscle, immediately outside the thyroid axis. The cardiac
nerves of the left side, descending from the neck, are close to the
artery.

THE SECOND PART OF THE SUBCLAVIAN ARTERY, the short portion con-

SUBCLAVIAN ARTERIES. 381

cealed by the anterior scalenus muscle, forms the highest part of the
arch described by the vessel across the neck. Somewhat less deeply

Fig. 255.—Virw or tHE RicgHt Common CAROTID AND OBCLAVIAN ARTERIES, WITH
THE ORIGINS OF THEIR BRANCHES AND THEIR RELATIONS (R. Quain). 4

For the explanation of the references in the upper part of this figure, see p. 356.
The following explanation relates to the subclavian artery and its branches: 8, the first
part, 8’, the third part, of the arch of the subclavian artery; 8”, the subclavian vein,
shown by the removal of a portion of the clavicle ; 9, is placed on the scalenus anticus
muscle in the angle between the transverse cervical and suprascapular branches of the
thyroid axis ; 10, outer part of the suprascapular artery ; 10’, transverse cervical branches
passing into the deep surface of the trapezius; 10”, the posterior scapular artery,
represented as rising directly from the third part of the subclavian artery, and passing
through the axillary plexus of nerves and under the levator anguli scapule ; 11, on
the scalenus anticus muscle, points to the inferior thyroid artery, near the place where
the ascending cervical artery is given off ; the phrenic nerve lies on the muscle to the
outside ; 7, the supra-sternal twig of the suprascapular artery.

2

382 THE SUBCLAVIAN ARTERY,

placed than the first part, it is covered by the platysma and the sterno-
mastoid muscle, with layers of the cervical fascia. Behind, it rests
against the middle scalenus muscle ; and below, it lies on the pleura.

Relation to Veins and Nerves.—The subclavian vein is lower than the
artery, and is separated from it by the anterior scalenus muscle. The
phrenic nerve, which descends obliquely inwards over that muscle,
usually crosses the first part of the subclavian artery of the left side
close to the muscle, while on the right side, not having quite reached
the margin of the muscle at the level of the artery, it is usually sepa-
rated by the muscle from the second part of the artery.

THE THIRD PART OF THE SUBCLAVIAN ARTERY lies in a small triangular
space, the sides of which are formed by the omo-hyoid muscle and
clavicle, and the base by the anterior scalenus muscle ; the omo-hyoid
is In some instances immediately over the artery. ‘The subclavian artery
is nearer to the surface here than elsewhere, being covered only bv
the platysma and layers of the cervical fascia, but towards its termina-
tion it becomes deeper, sinking under the clavicle and the subclavius
muscle.

Relation to Veins.—The subclavian vein continues to be anterior to,
and lower than the artery. The ezlernal jugular vein lies over the
artery, and receives on the outer side from the shoulder the two veins
which accompany the supra-scapular and transverse cervical arteries.
The veins in some cases form a sort of plexus over the artery.

Relation to Nerves——Above the vessel are placed the large brachial
nerves, the lowest cord formed by the union of the last cervical and the
first dorsal nerve being behind and in contact with it. The small
nerve of the subclavius muscle passes down over the artery, and the
space which lodges the artery is crossed in front by the superficial
descending (clavicular) branches from the cervical plexus of nerves.

BraNncHes.—Four branches are usually described as arising from
each subclavian artery. Of these, three, namely, the eeriebral, the
internal mammary, and the thyroid axis, generally spring close together
from the first part of the artery, near the inner side of the anterior
scalenus muscle; while the fourth branch, the superior intercostal, is
usually found internal to that muscle on the left side, but arising under
cover of it, from the second part of the artery on the right.

The vertebral artery springs from the upper and back part of the
subclavian, and ascends in the neck to reach the interior of the skull ;
the internal mammary proceeds from the lower side of the vessel, and
descends into the fore part of the chest and abdomen ; the thyroid axis
arises from the front of the artery, and divides into three branches, one
of which, the inferior thyroid, is distributed in the fore part of the neck,
whilst the other two, the suprascapular and the transverse cervical, pass
outwards across the neck to the shoulder ; lastly, the superior intercostal
and deep cervical arise by a common stem from the back part of the
artery, and pass into the upper part of the thoracic wall and the
posterior muscles of the neck. The deep cervical is reckoned by some
writers as a fifth branch of the subclavian artery, but it usually rises in
common with the superior intercostal artery.

Another branch, in the great majority of instances, arises from the
third part of the artery. ‘This is the posterior scapular artery, a branch
which otherwise is derived from the transverse cervical, one of the divi-
sions of the thyroid axis.

VERTEBRAL ARTERY, 383

Varieties.—The variations in origin of the subclavian arteries have been con-
sidered along with the peculiarities of the arch of the aorta.

Course —The height to which these vessels reach in the neck is liable to some
variation. Most commonly the artery crosses the neck a little higher than the
clavicle, but it is sometimes, especially on the right side, placed as high as an
inch or even an inch and a half above the level of that bone. Occasionally the
subclavian artery perforates the anterior scalenus muscle, and in a few rare
cases it has been seen altogether in front of the muscle, and close to the sub-
clavian vein. That vein has been also seen to pass with the artery behind the
scalenus muscle.

Branches.—Besides the variation in the position of the branches already referred
to, it may be noticed that, in a few cases, one or more of the three first branches
have been found moved inwards from their usual position, or outwards to another
division of the subclavian. Sometimes two, and much more rarely three branches
arise from the third part of the vessel.

BRANCHES OF THE SUBCLAVIAN ARTERY.

1. Vertebral Artery.—The vertebral artery, which is usually the
first and largest branch of the subclavian, arises from the upper and

ack part of that vessel, and passing upwards and a little backwards,
enters the transverse foramen of the sixth cervical vertebra—not unfre-
quently that of one of the higher vertebrae. The vessel then ascends in a
vertical direction through the series of foramina of the transverse pro-
cesses, as far as to the upper border of the axis ; thence it inclines out-
wards to reach the corresponding foramen of the atlas, and after passing
through that aperture winds backwards and inwards in the groove on
the neural arch of that vertebra, and, piercing the dura mater, enters
the skull through the foramen magnum. Finally, it proceeds upwards
and forwards, and turning round from the side to the front of the
medulla oblongata on the basilar process of the occipital bone, unites
with the vessel of the opposite side, at the lower border of the pons
Varolii, to form the basilar artery.

At its commencement, the vertebral artery lies behind the internal
jugular vein, and on approaching the vertebrae passes between the
longus colli and the scalenus anticus muscle. On the left side, the
thoracic duct in ascending crosses in front of the vessel from within
outwards.

While within the foramina of the cervical vertebrae, the artery is
accompanied by a plexus of the sympathetic nerves and by the verte-
bral vein, which, as the vessels issue from the foramen of the sixth
vertebra, is in front of the artery: the cervical nerves as they emerge
from the intervertebral foramina lie behind it. The suboccipital
nerve passes out beneath it, where it lies on the groove of the
atlas, and at that point the artery is covered by the superior oblique
‘muscle.

Within the skull it turns round the side of the medulla oblongata,
between the origin of the hypoglossal nerve and the anterior root of the
sub-occipital, and then lies between the anterior surface of the medulla
and the basilar process of the occipital bone.

Branches.—A. Cervical Branches:

(a) In the neck, the vertebral artery sends off at different points of its course
several small branches named lateral spinal arteries. Hach of these entering the
spinal canal through an intervertebral foramen divides into two branches; one

384 THE SUBCLAVIAN ARTERY.

passes along the roots of the spinal nerves, supplying the spinal cord and its
membranes, and anastomoses with the other spinal arteries; the other branch
ramifies on the back part of the bodies of the vertebree in the same manner as
similar branches derived from the intercostal and lumbar arteries.

(b) Muscular branches of variable size are distributed to the deep-seated cervical
muscles.

L. Cranial branches:

(a) The posterior meningeal artery is a small branch which arises opposite the
foramen magnum, and ramifies between the dura mater and the bone in the
occipital fossa, and upon the falx cerebelli. There are sometimes two of these
small vessels.

(b) The posterior spinal artery, arising at an obtuse angle from the vertebral,
inclines backwards round the medulla oblongata to reach the back part of the
spinal cord ; aided by reinforcements from small arteries which ascend upon the
cervical and dorsal nerves through the intervertebral foramina, it may be traced
along the cord, lying behind the roots of the nerves, as a minute tortuous vessel,
or rather a series of little inosculating vessels, as far as the second lumbar vertebra,
where it terminates in ramifications on the canda equina.

Fig. 256. Fig. 256. —Dnzp Drs-
ae SECTION OF THE Sub-

CLAVIAN ARTERY ON
THE RIGHT SIDE, SHOW-
ING THE ORIGIN AND
COURSE OF THE VER-
TEBRAL ARTERY (from
Tiedemann). 4

a, Upper part of the
sterno-mastoid muscle, its
clavicular part divided
below ; 6, spinous process
of the axis; c, superior
oblique muscle ; d, placed
on the inferior oblique
muscle, points by a line
to the posterior arch of
the atlas vertebra; e¢,
semispinalis colli; f,
placed on the longus
colli, points to the trans-
verse process of the sixth
cervical vertebra ; 7, on
the first rib, points to
the scalenus anticus mus-
cle cut near its attach-
ment ; 1, innominate
artery ; 2, right common
carotid ; 3, right sub-
clavyian ; below it, the
origin of the internal
mammary artery ; above
it, 4, the thyroid axis,
its branches cut short ;
5, vertebral artery, pass-
ing up through the canal
of the tramsverse pro-
cesses and giving branches
to the muscles ; 5’, placed
on the rectus major, points to its horizontal part on tL# arch of the atlas ; 6, placed on
the lower part of the divided scalenus medius, points to the trunk of the deep cervical
artery ; 7, occipital artery emerging from below the sterno-mastoid and other muscles
attached to the mastoid process,

THE VERTEBRAL ARTERY. 385

(ce) The anterior spinal artery, somewhat larger than the preceding, arises near
the end of the vertebral artery, and descends obliquely in front of the medulla
oblongata. Immediately below the foramen magnum, it unites with the cor-
responding vessel of the opposite side, so as to form a single trunk, which
descends a short distance only along the middle line in front of the spinal cord,
forming the upper part or commencement of the anterior median artery of the
cord. This anterior spinal branch of the vertebral artery supplies therefore only
the upper part of the cord ; the remainder being provided with a series of small
arteries, which are derived in the neck from the vertebral and inferior thyroid
arteries, in the back from the intercostals, and below this from the lumbar, ilio-
lumbar, and lateral sacral arteries. These small vessels enter the spinal canal at
irregular intervals through the intervertebral foramina, and, passing along the
roots of the nerves, communicate with each other along the middle line by means
of ascending and descending branches ; so that, by a succession of anastomoses, a
very slender single vessel, of varying thickness, named the anterior median artery,
appears to extend from the one end to the other of the cord. This vessel, or
chain of inosculating vessels, supplies the pia mater and the substance of the
cord—some entering the anterior median fissure. At the lower end of the spinal
cord it sends branches downwards on the cauda equina.

On a part of the spiual cord near the lower end, and in front of the posterior
roots of the nerves, may be found another small artery, about equal in size to the
anterior spinal.

(d) The posterior inferior cerebellar artery, the largest of the branches, arises
from the vertebral near the pons, and sometimes from the basilar artery : it
turns backwards and outwards, between the hypoglossal and pneumogastric
nerves, over the restiform body and near the side of the opening of the fourth
ventricle to reach the under surface of the cerebellum. Here, running back-
wards between the inferior vermiform process and the hemisphere, it divides into
two branches: one of which continues backwards in the sulcus between the
hemispheres ; while the other, turning outwards, ramifies on the under surface of
the cerebellum as far as its outer border, over which the ultimate divisions of
each branch anastomose with those of the superior cerebellar arteries. This
artery partly supplies the hemisphere and the vermiform process, and gives
branches to the choroid plexus of the fourth ventricle.

Varieties.— Origin.—The right vertebral artery has been seen to arise from
the common carotid of the same side, in some of those cases in which the right
subclavian has been given as a separate vessel from the posterior part of the
aorta. In very rare instances, the right vertebral artery arises from the aorta.

The left vertebral artery is not unfrequently derived from the aorta, in which
case it generally arises between the left carotid and subclavian arteries, but
sometimes it is the last of the branches from the arch.

The left vertebral artery in a few instances, and the right vertebral in one,
have been found to arise by more than a single root; and an example of three
roots to a vertebral artery has been placed on record. (R. Quain, plate 24, fig. 2.)
Two roots may proceed from the subclavian artery, or one from the subclavian
and one from the aorta.

Course.—Instead of entering the foramen of the sixth vertebra, the vertebral
artery of one side not unfrequently enters higher up, through the foramen of the
fifth, or fourth, or more rarely of the third vertebra, or even, according to several
anatomists, of the second. On the other hand, the vertebral artery has been
seen to enter the foramen of the seventh vertebra.

Branches.—In the neck, the vertebral artery has been found, though very
rarely, to give branches which are usually derived from the subclavian, such as
the superior intercostal and the inferior thyroid.

The basilar artery the single trunk formed by the junction of the right
and left vertebral arteries in the middle line, extends from the posterior
to the anterior border of the pons Varolii, along the median groove of
which it lies under cover of the arachnoid. The length of this artezy is

therefore about equal to that of the pons, at the anterior border of
VOL. I. ce

386 THE SUBCLAVIAN ARTERY.

which it divides into two terminal branches, the posterior arteries of
the cerebrum.

Branches. —Besides numerous small branches to the substance of the pons, the
basilar artery gives off the following :—

(a) The transverse arteries, several on each side, pass directly outwards. One,
the artery of the auditory nerve, accompanies that nerve into the internal auditory
meatus and labyrinth of the ear.

(b) The anterior inferior cerebellar arteries pass backwards, one on each side, to
the anterior part of the under surface of the cerebellum, anastomosing with the
inferior cerebellar branches of the vertebral arteries.

(c) The superior cerebellar arteries arise so close to the bifurcation of the
basilar, that this artery is described by several anatomists as dividing into four
branches. Each one turns backwards and outwards immediately behind the third
nerve, and entering the groove between the pons Varolii and the crus cerebri,
turns round the latter, close to the fourth nerve, to reach the upper surface of
the cerebellum, where it divides into branches. Of these some extend outwards,
and one or more backwards along the superior vermiform process, to reach the
circumference of the cerebellum, where they anastomose with the branches of the
inferior cerebellar arteries: while others run inwards to supply the vermiform
process and the valve of Vieussens, and in part the velum interpositum.

The posterior cerebral artery on each side, resulting from the
division of the basilar, passes outwards, parallel to the superior cere-
bellar artery, and separated from it at its origin by the third nerve,
which comes forwards between the two vessels. It turns backwards
round the crus cerebri, and then runs outwards and upwards on the
under surface of the posterior lobe of the cerebrum, passing near the
posterior extremity of the corpus callosum, It divides beneath the
posterior lobe into many branches, which ramify upon the under,
median, and outer surfaces, and anastomose with the other cerebral
arteries.

Branches.—Immediately after its origin the posterior cerebral artery gives off
numerous small parallel branches, which perforate the substance of the brain
between the crura, at the point which is called from this circumstance the pos-
terior perforated spot. As it turns backwards, a short distance from its origin,
this artery is joined by the posterior communicating artery, and in this way con-
tributes as already described (p. 363) to form the circle of Willis. Lastly, the
posterior cerebral gives origin to a small branch, the posterior choroid, which,
arising external to the junction of the communicating artery, turns backwards
over the crus cerebri and the tubercula quadrigemina, supplying these with
branches, and ending in the velum interpositum and choroid plexus, in the
interior of the brain.

Varieties.—The basilar artery is originally formed by the coalescence of two
separate vertebral arteries, and traces of a septum are sometimes found in its
interior. (Davy, ‘“ Researches,” &c., vol. i. p. 301.) The occurrence of a perfora-
tion of the vessel, which has also been observed, may be likewise attributed to the
incomplete fusion of the two arteries.

The posterior cerebral artery is occasionally given off on one side from the
internal carotid artery.

_ 2.—Thyroid axis.—The thyroid axis springs from the fore part of

the subclavian artery, close to the inner side of the anterior scalenus
muscle. It is a short thick trunk, and receives the name of “ axis,”
because, at a line or two from its origin, it divides into branches, which
diverge in different directions, viz., the inferior or ascending thyroid,
the suprascapular, and a third branch, which is either the transverse

THE THYROID AXIS. 387

cervical, or one of the branches into which that artery, when present,
divides, viz., the superficial cervical.

Varieties.—The thyroid axis has been known to arise beyond the scalenus
anticus muscle, It may be associated at its origin with another branch ; thus, it
sometimes give origin to the internal mammary, and has been known to give
origin to the vertebral, superior intercostal, or deep cervical arteries,

A. The inferior thyroid artery passes directly upwards, resting on
the longus colli muscle, and after a short course bends inwards and
downwards behind the sheath of the large cervical vessels, and also
behind the sympathetic nerve (the middle cervical ganglion of which,
when present, often rests upon this vessel). The artery then makes
another curve in the opposite direction, and is distributed to the under
part of the thyroid body. Its branches communicate freely with those
-of the superior thyroid artery, and with the corresponding artery of the
other side.

Branches.—(a) The ascending cervical branch arises at the point where the
inferior thyroid turns inwards behind the carotid artery ; it proceeds upwards,
close to the phrenic nerve, on the line of separation between the scalenus anticus
and rectus anticus major, giving muscular branches to both, and a few which
pass transversely outwards across the neck. These muscular branches commu-
nicate with others sent outwards from the vertebral artery. To the spinal canal
the ascending cervical artery sends one or two branches (spinal branches), which
enter the intervertebral foramina along the cervical nerves, and assist in sup-
plying the bodies of the vertebree, and the spinal cord and its membranes.

(0) A laryngeal branch of irregular size is usually supplied by the inferior
thyroid artery ; it ascends on the trachea and the back of the larynx, and is dis-
tributed to the muscles and mucous membrane in that situation.

(c) Tracheal branches ramify over the trachea, and anastomose below with the
bronchial arteries.

(d) Gsophageal branches are given off, and one or more descend upon the
trachea into the chest.

Varieties. — Origin—The inferior thyroid artery occasionally arises as an
independent branch from the subclavian artery, and rarely from the common
carotid or the vertebral. Instances have occurred—very rarely, however—of the
presence of two inferior thyroid arteries, one passing over the common carotid
artery.

The ascending cervical artery is occasionally derived from the subclavian or
from one of the branches of that vessel, as from the transverse cervical or the
suprascapular, or from a trunk common to those two arteries. It is sometimes
much larger than usual, and takes the place of the occipital artery. A branch
from it not unfrequently compensates for the small size of the deep cervical
artery.

B. The suprascapular artery (transverse scapular, or transverse
humeral), a smaller vessel than the transverse cervical arises almost
constantly from the thyroid axis, and runs from within outwards deeply
at the root of the neck. At first it descends obliquely towards the
clavicle, resting upon the scalenus anticus, and covered by the sterno-
mastoid muscle; it then crosses the subclavian artery, and continues
transversely outwards behind and parallel with the clavicle and sub-
clavius muscle, and below the posterior half of the omo-hyoid
muscle. Approaching the upper margin of the scapula, under
cover of the trapezius muscle, it inclines downwards with the supra-
scapular nerve towards the suprascapular notch. At this point the

‘nerve usually passes beneath the ligament stretched across the notch,
cc2

388 THE SUBCLAVIAN ARTERY.

while the artery more frequently turns over to it to enter the supra-
spinous fossa, where, lying close to the bone, it gives off branches which
ramify in the fossa beneath the supraspinatus muscle, and sends a small

Fig. 257. Fig. 257.—Vinw oF
THE ANASTOMOSES
oF ARTERIES ON
THE SHOULDER
And DorsumM OF
mHE ScaPULA (from

Tiedemann). 4%

a, sterno-mastoid
muscle ; 6, trapezius
turned towards the
left side ; c, splenius
capitis, and below it
splenius colli; 4,
levator anguli sca-
pule ; e, serratus
posticus superior ; f,
rhomboideus minor,
and g, rhomboideus
major, divided from
the base of the sca-
pula ; A, teres major,
i, teres minor; fk,
scapular head of the
triceps brachii; J,
serratus Magnus ; ,.
latissimus dorsi; 7,
deep surface of the
deltoid muscle turned
down ; 0, portion of
the infraspinatus
muscle attached to
the great tuberosity
of the humerus, the
rest having been re-
moved from the in-
fraspinous fossa ; 1,
occipital artery ap-
pearing between the
trapezius and sterno-
mastoid muscles ; 2,
superficial _ cervical
branch of the trans-
verse cervical artery ;
2', 2’, posterior sca-
pular artery; 2 +,
its supraspinous
branch ; 38, supra-
scapular artery; 3’,
the same after pass-
ing through the sca-
pular notch into the
infraspinous fossa,
where it anastomoses
with 4, the dorsal

pranch of the subscapular artery ; 4’, inferior scapular branch of the subscapular; 4”,
some of the descending thoracic branches of the subscapular artery ; 5, posterior circumflex
artery emerging from the quadrangular space, and sending branches upwards on the
shoulder-joint, round the humerus, and downwards into the deltoid muscle ; 6, anasto-
mosis of the acromial branches of the suprascapular with the acromio-thoracic artery.

THE TRANSVERSE CERVICAL ARTERY. 389

communicating branch into the subscapular fossa, and is itself con-
tinued down into the infraspinous fossa.

Branches.— Muscular branches are given by the suprascapular artery to the
sterno-mastoid and other neighbouring muscles.

(6) The supra-acromial branch passes obliquely forwards through the attach-
ment of the trapezius to reach the cutaneous surface of the acromion, on which
it ramifies, anastomosing with offsets from the acromio-thoracic artery.

(c) A small subscapular branch, given off as the artery passes over the notch,
anastomoses with the posterior scapular and subscapular arteries in the sub-
scapular fossa and substance of the subscapularis muscle.

(d) An infraspinous branch is continued from the suprascapular artery, and
descending close upon the neck of the scapula, between the glenoid cavity and
the spine of that bone, joins with the dorsal branch of the subscapular artery.

(e) Branches enter the bone and shoulder joint.

WVarieties.—The suprascapular artery has in some cases been observed to spring
directly from the subclavian, or to arise from that vessel by a common trunk
with the transverse cervical, or more rarely with the internal mammary.
It has also been found to proceed from the axillary artery, and from the sub-
scapular branch of that vessel.

C. The transverse cervical artery, the third branch of the thyroid
axis, passes outwards a short distance above the clavicle, and therefore
higher than the suprascapular artery. It crosses over the scaleni
muscles and the brachial plexus, sometimes passing between the nerves
of the latter, and is crossed by the omo-hyoid muscle. Beneath the
anterior margin of the trapezius, and near the outer edge of the levator
anguli scapule, it divides into two branches, the superficial cervical and
the posterior scapular.

The superficial cervical artery ascends beneath the anterior border of
the trapezius, and distributes branches to that muscle, the levator
anguli scapule, and sterno-mastoid muscles, as well as to the cervical
glands and the integuments in the intervals between those muscles.
When the posterior scapular arises separately from the subclavian, the
name superficial cervical may be given to the whole remaining part of
the transverse cervical artery.

The posterior scapular artery, whether arising from the transverse
cervical artery or directly from the subclavian, passes backwards to the
upper angle of the scapula, under cover of the levator anguli scapule,
and then changing its direction, runs downwards beneath the rhom.-
boidei muscles, as far as the inferior angle of that bone. It anasto-
moses freely on both surfaces of the scapula with the divisions of the
suprascapular and subscapular arteries ; and supplies branches to the
rhomboidei, serratus magnus, and latissimus dorsi muscles, communi-
cating at the same time with the posterior muscular branches of some
of the intercostal arteries.

Varieties.—Not only does the transverse cervical branch of the thyroid axis
present the variation of being nearly as often the superficial cervical alone as of
comprising also the posterior scapular artery, but it occasionally happens that the
vessel derived from the thyroid axis is very small, and represents only in part the
superficial cervical artery ; whilst a large vessel arising from the third part of
the subclavian divides near the levator anguli scapule into two branches, of
which one ascends and represents the remaining and larger portion of the super-
ficial cervical artery, while the other forms the posterior scapular.

The transverse cervical artery is sometimes derived directly from the subclavian,
beneath or even beyond the scalenus anticus muscle. The transverse cervical
sometimes gives off the ascending cervical artery.

390 THE SUBCLAVIAN ARTERY.

When the superficial cervical is separated from the posterior scapular, it some--
times arises from other sources than the thyroid axis, as from the suprascapular
or the subclavian artery.

Fig. 258. Fig. 258.—DIssEcTION OF THE RIGHT SIDE

- OF THE ANTERIOR THORACIC AND AB-
DOMINAL WALL, TO SHOW THE ANASTO-
MOSES OF THE InTERNAL Mammary.
INTERCOSTAL, AND Epigastric VESSELS
(slightly altered from Tiedemann),
(A. T.) 4

The pectoral part of the serratus mag-
nus, the external and internal oblique,.
and the rectus abdominis muscles, have:
been removed ; 1, upon the subclayius
muscle, points to the first part of the:
axillary artery above the pectoralis minor
muscle, giving rise to the acromio-thoracic
artery, which is cut short; 2, upon the
pectoralis minor, points to the lower part.
of the axillary artery and vein; 3, the
long thoracic artery ; 4, on the cartilage of
the first rib, marks the upper part of the
internal mammary artery ; 4’, the lower:
part of the same artery giving its abdominal
branch behind the cartilage of the seventh
rib; 5, in the fourth intercostal space,
marks the anastomosis of the internal
mammary and intercostal arteries ; 6,
anterior branches of the internal mam-
mary artery ramifying over the front of the
sternum ; 7, on the transversalis muscle:
immediately above the internal inguinal
aperture, points to the last part of the ex-
ternal iliac artery, from which are seen
rising, 8, the deep epigastric artery, and
9, the deep circumflex iliac ; 10, the anas-
tomosis of the epigastric with the abdomi-
nal branch of the internal mammary
artery ; 11, the spermatic cord and sper-
matic twig of the epigastric artery ; 12,
the femoral artery ; 13, the femoral vein ;.
14, a lymphatic gland closing the femoral
ring.

3.—Internal Mammary Ar-
tery. — The internal mammary
artery, remarkable for its length
and the number of its branches,
arises from the under side of the:
subclavian, opposite the thyroid
axis. It runs forwards and down-
wards behind the clavicle to the
inner surface of the cartilage of
the first rib, lying between this
and the sac of the pleura: from
this point it inclines a little inwards, and then descends vertically
behind the costal cartilages, a sho t distance from the border of the
sternum, as far as to the interval between the sixth. and seventh
cartilages, where it ends by dividing into two branches. One of the

THE INTERNAL MAMMARY ARTERY, 391

branches into which the artery divides, musculo-phrenic, inclines out-
wards along the margin of the thorax; while the other, under the
name of superior epigastric, continues onwards to the abdomen in the
original direction of the trunk. The internal mammary artery is
covered at its origin by the internal jugular and subclavian veins,
and is crossed in front by the phrenic nerve. In the chest it has the
costal cartilages and the internal intercostal muscles in front, and lies at
first upon the pleura ; but lower down it is separated from the pleura by
the triangularis sterni muscle. This artery has two companion veins,
which are united into a single trunk at the upper part of the chest.

Branches.—The branches of this artery are numerous, and are distributed
chiefly to the walls of the chest and abdomen.

(a) The superior phrenic or comes nervi phrenici, a very slender but long branch,
arises high in the chest, and descends with the phrenic nerve between the
pleura and the pericardium, to the diaphragm, in which it is distributed, anasto-
mosing with offsets from the musculo-phrenic and with the inferior phrenic
arteries from the abdominal aorta.

(b) The mediastinal or thymic branches, of very small size, ramify in the loose
connective tissue of the mediastinal space, and supply the thymus body or its
remains. Pericardiac branches are given off directly to the upper part of the
pericardium, the lower part of which receives some from the musculo-phrenic
division. Branches named ste7nal are also supplied to the triangularis sterni
muscle, and to both surfaces of the sternum.

(c) The anterior intercostal arterics, two in each space, arise from the internal
mammary, either separately, or by a trunk common to the two, which soon
divides. The arteries pass outwards, at first between the pleura and the internal
intercostal muscles, and afterwards between the two layers of intercostals ; they
lie, one near the upper and one near the lower rib, in each of the upper five or
six intercostal spaces, and inosculate with the corresponding intercostal branches
derived from the aortic intercostals. These branches supply the intercostal and
pectoral muscles, and give some offsets to the mamma and integument.

(d) The anterior or perforating branches pass forwards from the internal
mammary artery through from four to six intercostal spaces, and turning out-
wards ramify partly in the pectoralis major, and partly in the integument on the
front of the chest. Those placed nearest to the mammary gland supply that
organ, and in the female they are of comparatively large size, especially during
lactation. Some offsets ramify on the sternum.

(ce) The musculo-phrenic artery, the outer of the two branches into which the
internal mammary artery divides, inclines downwards and outwards behind the
cartilages of the false ribs, perforating the attachment of the diaphragm at the
eighth or ninth rib, and becoming gradually reduced in size as it reaches the last
intercostal space. It gives branches backwards into the diaphragm ; others,
which pass outwards to form the anterior intercostals of each space, and are
disposed precisely like those which are derived higher up from the main internal
mammary ; and some which descend into the abdominal muscles.

(f) The abdominal branch or superior epigastric artery of the internal mam-
mary, descending into the wall of the abdomen, lies behind the rectus, between
the muscle and its sheath ; and afterwards, entering the muscle, terminates in
its substance, at the same time anastomosing with the epigastric artery. It also
supplies twigs to the broad muscles of the belly, to the skin, and to the dia-
phragm ; and one runs forwards upon the side and front of the xiphoid cartilage,
where it anastomoses with that of the opposite side.

Varieties. —The internal mammary is occasionally found connected at its
origin with the thyroid axis, or with the scapular arteries—these being detached
from the thyroid. It occasionally springs from the second or third part of the
subclavian artery (the latter being the more frequent position of the two). In
very rare instances it has been found arising from the axillary, the innominate,
or the aorta,

392 THE SUBCLAVIAN ARTERY.

An unusual branch, of considerable size, occasionally comes off from it, and
passes downwards and outwards, crossing several of the ribs, on their inner
surface, in contact with the pleura, The internal mammary artery may likewise
furnish a bronchial branch.

4.—Superior Intercostal Artery.—This artery generally arises
from the upper and back part of the subclavian, behind the anterior
scalenus muscle on the right side, and immediately at the inner side of
the muscle on the left side. ‘Taking its course backwards, it speedily
gives off the deep cervical branch (profunda cervicis), and bending
backwards and downwards in front of the neck of the first rib, ends in
one or two intercostal spaces: on the right side it more frequently
descends into the second space than on the left side. On the neck of
the first rib, the artery is situated on the outer side of the first dorsal
ganglion of the sympathetic nerve.

Branches.—Besides giving off the deep cervical artery, the superior intercostal
gives branches to the first and second intercostal spaces. The branch to the first
space is similar in course and distribution to the aortic intercostals: that to the
second space usually joins with one from the first aortic intercostal. A small
offset is likewise sent backwards, through the first space, to the posterior spinal
muscles, and also a small one through the corresponding intervertebral foramen
to the spinal cord and its membranes.

Varieties.— Origin.—The superior intercostal artery has been found, in a few
instances, to proceed from the vertebral artery or from the thyroid axis.

Cowrse.—It has been observed to pass between the necks of one or two ribs
and the corresponding transverse processes of the dorsal vertebra ; and a case has
been recorded in which, after arising from the vertebral artery, it descended
through the intertransverse foramen of the last cervical vertebra, and then
continued, as in the instances just mentioned, between the necks of the ribs and
the contiguous transverse processes of the vertebrae of the back. (Quain on the
Arteries, plate 22, fig. 5.) The intercostal artery is sometimes, though very rarely,
wanting.

The deep cervical artery, often described as a separate branch of the
subclavian artery, arises in most cases from the superior intercostal.
Resembling the posterior branch of an aortic intercostal artery, it gene-
rally passes backwards in the interval between the transverse process
of the last cervical vertebra and the first rib, to reach the posterior
aspect of the neck. Here it ascends in the interval between the trans-
verse and spinous processes, as high as the second vertebra, under cover
of the complexus muscle, between this and the semi-spinalis colli. Some
of the branches communicate with those given outwards by the verte-
bral artery, whilst others ascend to anastomose with the cervical branch
of the occipital artery.

Varieties.— Origin.—The deep cervical artery sometimes arises from the sub-
clavian, and more rarely from the posterior scapular. It is not unfrequently
supplemented by a branch turning backwards from the ascending cervical artery
beneath the transverse process of the third cervical vertebra, or by another branch
from the superior intercostal, or, in some instances, by a twig from the posterior
scapular or inferior thyroid arteries.

Course.— This artery occasionally passes back between the sixth and seventh
cervical vertebra, and sometimes between the first and second dorsal, or even
below the second. It has been seen to pass between the first rib and the trans-
verse process which supports it.

SURGICAL ANATOMY OF THE SUBCLAVIAN ARTERIES
The depth of the subclavian artery, its intimate and varying connections with

SURGICAL ANATOMY OF SUBCLAVIAN ARTERIES. 393

important parts, and the large size ef its branches, render operations on this
vessel peculiarly difficult.

The third division of the artery, situated beyond the anterior scalenus muscle
is the part which is most favourably circumstanced for the application of a
ligature. Here the vessel is nearest to the surface, and most remote from the
origin of the large branches. The subclavian artery is generally most easy of
access above the clavicle while the parts are in their natural position, but when
they are displaced by an aneurism in the axilla, the clavicle may be so much
elevated by the tumour, as to be placed in front of the vessel, or even above it ;
and such a condition may require special modifications of the operation.

In the operation of passing a ligature round the third part of the subclavian
artery, an incision is to be made a little above the most prominent or convex
part of the clavicle, opposite the place where the vessel lies, and parallel with it.
By drawing the integument downwards over the claviele, the parts covering the
bone may be divided with freedom.

Along with the integument, the platysma and several nerves are divided in
this incision, but no vessel is endangered, except in those rare cases in which the
cephalic vein or the external jugular crosses over the clavicle. It will, in most
cases, be an advantage to add a short vertical incision, directed downwards to
the middle of the horizontal one. Should the sterno-mastoid muscle be broad at
its lower end, or should the interval between that muscle and the trapezius be
insufficient for the farther steps of the operation, a portion of the former muscle,
or even of both muscles, must be divided.

The external jugular vein, joined by the veins from the shoulder, is usually
over the artery, and it must be held aside, or it may be necessary to divide
it. If divided, the lower end of the vessel requires the application of a liga-
ture as well as the upper one, in consequence of the reflux of blood from the
subclavian vein. The omo-hyoid muscle will also be turned aside if necessary.
At this stage of the operation, in the usual position of the clavicle, the first rib
is the best guide to the vessel. At this place the brachial nerves are close to the
vessel, so that great care must be exercised in passing the ligature round the
artery. But if it is found necessary to raise greatly the outer end of the clavicle,
then it will, in many cases, be more easy to place the ligature on the artery inside
the insertion of the scalenus muscle, or even behind that muscle. Above the
first rib, the situation of the vessel may be ascertained by means of the brachial
nerves and the scalenus muscle; and, before the membrane covering them is
divided, the position of these structures may be ascertained by the cord-like feel
of the nerves, and the smooth, flat form of the muscle.

With reference also to the choice of the exact place at which the ligature is to
be passed round this part of the artery, it should always be borne in mind that
a very considerable branch may be given off from the main artery, immediately
beyond the scalenus muscle, or at some other part of the vessel. This branch is
most frequently one corresponding to the posterior scapular; but in rarer cases
may be the superficial cervical or suprascapular.

The second division of the subclavian artery, ox that situated behind the scalenus
anticus miiscle, is the part which rises highest in the neck, and on this account
it may be advantageously selected for the application of a ligature when the
vessel is clifficult of access beyond the muscle. The chief objection to operating
on this part of the artery arises from the contiguity of the large branches. Care
is necessary in dividing the scalenus muscle to avoid the phrenic nerve and the
internal jugular vein. Moreover, the fact of the close apposition of the subcla-
vian ajtery with the pleura, except where it rests on the rib, must be borne in
mind,

Difficulties also arise from the occurrence of an unusual position of the artery,
as when it passes through the substance of the anterior scalenus, or when it is
in front of that muscle ; but such cases are of very rare occurrence.

The first part of the subclavian artery on the left side may be said to be
inaccessible for the application of a ligature, in consequence of its depth and its
close connection with the lung and other important structures, such as the internal
jugular and left innominate veins.

394 THE AXILLARY ARTERY.

On the right side, though deeply placed and closely connected with important
parts, the first division of the subclavian artery may be tied without extreme
difficulty. But inasmuch as the length of the vessel, between its three large
branches on the one hand, and the common carotid on the other, ordinarily
measures no more than an inch, and often less; the success of the operation is
somewhat doubtful.

In order to place a ligature on the portion of the right subclavian artery here
referred to, it is necessary to divide by horizontal incisions the three muscles:
which cover it, together with the layers of fascia between and beneath them.
While the muscles are being divided, a branch of the suprascapular artery will
probably require to be secured. In the farther steps of the operation, the exact
relations of the artery to the internal jugular vein, the vagus nerve, and the
pleura, are to be well kept in view.

It is to be remembered also that the right subclavian artery is occasionally
somewhat more deeply placed than usual in the first part of its course; as in
certain cases of variation, when it springs from the back part of the aortic arch,
or, more frequently, when it merely separates from the innominate behind the
carotid,

AXILLARY ARTERY.

The axillary artery is that part of the artery of the upper limb which
extends from the outer border of the first rib to the lower margin of the
tendons of the latissimus dorsi and teres major muscles. In this
course it passes through the axilla, and its direction varies with the
position of the limb, being curved downwards, or upwards, or being
straight, according as the arm hangs by the side, or is elevated, or
extended.

In front, the axillary artery is covered by the pectoralis major muscle,.
behind which it is crossed by the pectoralis minor. It may be con-
veniently divided into three parts: the first part lying internal to the
pectoralis minor muscle, the second part being behind that muscle, and
the third part beyond it.

In the first part of its course the vessel has the first intercostal
space, and the first slip of the serratus magnus muscle with the posterior
thoracic nerve on its inner side, and is covered by the costo-coracoid
membrane, which, attached above to the clavicle, is continued below
into a common sheath investing the artery and vein, which is completed
behind by a prolongation of the deep cervical fascia. In this part of
its course the artery is placed with the trunks of the brachial plexus
above and behind it, and the axillary vein in front of it and somewhat
nearer the thorax: it is also crossed by the cephalic and acromio-
thoracic veins as they dip down to terminate in the axillary vein.

In the second part of its course, behind the pectoralis minor, the
axillary artery 1s completely surrounded by the trunks of the brachial
plexus, and is crossed in front by one of the roots of the median nerve =
the vein is on the thoracic side of the artery, separated from it by
nerves.

In the third part of its course, beyond the pectoralis minor, the
axillary artery rests on the subscapular muscle and the insertions of the
latissimus dorsi and teres major, while to the outer side is the coraco-
brachielis muscle. The axillary vein is still on the thoracic side, but
sometimes the vense comites, by whose union it is formed, are con-
tinued up to this level, one on each side of the artery. The main
branches resulting from the division of the brachial plexus of nerves
are disposed behind and on each side of this part of the artery, as.

THORACIC BRANCHES OF AXILLARY ARTERY. 395-

follows, viz., behind it, the circumflex and musculo-spiral; to its inner
side, the ulnar and the two internal cutaneous ; to the outer side, the
external cutaneous and median. ‘The external cutaneous and the
circumflex nerves leave the artery in the axilla, and at the lower part
of the axilla median nerve is often before the vessel; in an operation,
that nerve might serve as a guide to the position of the artery, for it
could be distinguished from the other large nerves (ulnar and musculo-
spiral) by the circumstance of its being the nearest to the pectoral
muscle. Beyond the border of the pectoralis major, the artery is
covered only by the skin and fascia on the inner side; and here the
flow of blood may be controlled by pressure of the finger directed out-
wards against the humerus.

BRANCHES OF THE AXILLARY ARTERY.

The branches of the axillary artery consist of the external thoracic
branches furnished to the muscles of the chest, the subscapular branch
to the shoulder, and the anterior and posterior circumflex branches to
the upper part of the arm. The branches are not constant in their
number, size, or mode of origin.

1. The short thoracic artery (thoracica suprema), a branch of incon-
siderable size, arises at a point internal to the pectoralis minor muscle,
and inclines downwards and inwards across the first two intercostal
spaces, anastomosing with the internal mammary and _ intercostal
branches contained in them, and terminates between the pectoral
muscles.

2. The acromio-thoracic axis (art. thoracica humeraria), of consider-
able size, and by far the most constant of the thoracic branches of the:
axillary, arises from its forepart at the inner border of the pectoralis
minor muscle, and goon divides into branches which take different
directions.

(a) The acromial branches pass partly to the deltoid muscle and partly to the:
upper surface of the acromion, and anastomose with the suprascapular and
posterior circumflex arteries.

(b) The humeral branch passes down in the interval between the pectoralis
major and deltoid muscles, and is distributed to their margins ; it is accompanied
by the cephalic vein.

(ec) The thoracic branches are distributed to the serratus magnus and pectoral
muscles, and anastomose with the other thoracic arteries.

(d) The claviculas branch, very small, passes inwards to the subclavius
muscle,

3. The long thoracic or external mammary artery is directed down-
wards and inwards, along the lower border of the pectoralis minor, and
is distributed to the mamma, and to the serratus and pectoral muscles,
and anastomoses with the external branches of the intercostal arteries. -

4. The alar thoracic branch is a very small vessel and not constant,
being frequently wanting, and having its place supplied by branches
from the thoracic and subscapular arteries. It is distributed to the
lymphatic glands and the fatty tissue in the axilla.

5. Subscapular Artery.—This branch, the largest given off by the
axillary artery, arises close to the lower border of the subscapular
muscle, along which it proceeds downwards and backwards, towards

OO
xo}
o>

THE AXILLARY ARTERY

SSS = —— Wi if i .
Fig. 259.—Dzxrp Virw oF THE Carotip, SubcLAvIAN, AND AXIuLARY ARrerres (from
Tiedemann), _ 3

The great pectoral, the sterno-mastoid, and the sterno-hyoid and sterno thyroid muscles
have been removed ; the front part of the deltoid has been divided near the clavicle : the
greater part of the digastric muscle has been removed, and the upper part of the splenius
capitis and trachelo-mastoid divided near the mastoid process. Subclavian Artery and
its Branches.—1, First or inner part of the subclavian artery giving rise to the thyroid
axis and internal mammary, and also to +, the vertebral artery ; 2, third part of the

SUBSCAPULAR ARTERY. 397

subclavian artery outside the scalenus anticus muscle ; 3, first part of the axillary artery
giving rise to the acromio-thoracic, short thoracic, &c. ; 4, third part of the axillary artery
giving rise to the subscapular, circumfles, &c. ; 5, commencement of the brachial artery ;
6, superficial transverse cervical artery ; 6’, placed on the scalenus anticus muscle, marks
the ascending cervical branch ; 7, posterior scapular artery arising from the subclavian
artery behind the scalenus anticus muscle ; 8, acromial branches of the acromio-thoracic ;
9, pectoral branches of the same; 10, long thoracic artery outside the pectoralis minor
muscle ; +, posterior circumflex branch of the axillary artery (the anterior circumflex
is seen rising from the opposite side of the same part of the axillary trunk ; 11, sub-
scapular artery passing between the subscapularis and teres minor muscles to proceed
to the lower angle and dorsum of the scapula ; 32, thoracic descending branch of the
subscapular artery. For the explanation of the references 13 to 27, to the carotid
artery and its branches see p. 368.

the inferior angle of the scapula, accompanied by the long subscapular
nerve; and it terminates in branches to the subscapularis, serratus
magnus, teres major, and latissimus dorsi muscles. It soon becomes
considerably diminished in size, owing to its giving off a large branch
to the dorsum of the scapula. Its final ramifications anastomose with
one another and with the branches of the posterior scapular artery.

Fig. 260.—View oF Fig. 260.
THE ARTERIES a4
WHICH RAMIFY AND
ANASTOMOSE ON THE
VENTRAL SURFACE
OF THE ‘ScaPuLa,
AND OF THE AN-
TERIOR CrRcuM-
FLEX ARTERY (from
R. Quain).

a, coracoid process ;
6, tendon of the long
head of the biceps
muscle ; c, the front
of the capsular liga-
ment of the shoulder-
joint ; d, tendon of
the latissimus dorsi
muscle; ¢, teres
major; 1, supra-
scapular artery de-
scending to the supra-
scapular notch, over
the ligament of which
the larger part of the artery passes into the supraspinous fossa ; A, A’, the axillary and
brachial artery; 1’, its subscapular branch passing through the notch and ramifying in
the subscapular fossa ; 2, 2, posterior scapular artery descending parallel to the base of
the scapula ; 2’, its subscapular branches ; 3, main stem of the subscapular artery at its
origin from the axillary and continuation towards the dorsum of the scapula; 3’, the
branch to the ventral surface of the scapula proceeding to anastomose with the sub-
scapular branches of the suprascapular and posterior scapular arteries ; 4, descending or
thoracic branch of the subscapular artery; 5, anterior circumflex artery ; 6, posterior
circumflex passing back through the quadrilateral muscular space.

The dorsal branch (dorsalis scapule) turns back from the subscapular
artery, about an inch and a half from its origin, and is sometimes larger
than the continuation of the vessel. Descending along the lower border
of the scapula, it passes through the interval bounded internally by the
subscapularis and teres minor, externally by the latissimus dorsi and
teres major, and superiorly by the long head of the triceps muscle ; and,

398 THE AXILLARY ARTERY.

turning closely round the border of the scapula, which is frequently
grooved to receive it, passes between the teres minor and the bone, and
ramifies in the infraspinous fossa, where it anastomoses with the supra-
scapular and posterior scapular arteries.

Branches.—The dorsalis scapule gives off,—(a) ventral branches, slender
vessels which ramify in the subscapular fossa between the subscapular muscle
and the bone, and anastomose with twigs from the suprascapular and posterior
scapular arteries ; (/) branches to the teres muscles, and particularly a twig which
descends between their origins ; (c) terminal branches in the infraspinous fossa.

6. The posterior circumflex artery, a considerable vessel but
smaller than the subscapular, arises opposite the lower border of the
subscapular muscle, below the subscapular artery, and is directed back-
wards in company with the circumflex nerve, passing through the
space between the teres muscles, the humerus, and the long head of the
triceps muscle, and therefore separated by the long head of the triceps
from the subscapular artery. It winds round the humerus, and ter-
minates by ramifying in the deltoid muscle and on the shoulder-joint,
and by anastomosing with the anterior circumflex and suprascapular
arteries, as well as with the acromio-thoracic.

7. The anterior circumflex artery, much smaller than the posterior
circumflex, arises nearly opposite to it or lower down, and from the outer
side of the axillary artery. It passes from within outwards and forwards,
under the inner head of the biceps and the coraco-brachialis muscle,
resting on the fore part of the humerus, until it reaches the bicipital
groove. There it divides into two branches, one of which ascends in
the groove with the long head of the biceps, to the head of the bone
and the capsule of the joint ; the other continues outwards, and anas
tomoses with the posterior circumflex branch.

Varieties.—The most important variety in the trunk of the axillary artery
consists in its giving off a much larger branch than usual,—an arrangement which -
has been observed in the proportion of one out of every ten cases. In one set of
cases, this large branch is continued as one of the arteries of the fore-arm ; most
frequently the radial (about one in 33), sometimes the ulnar (1 in 72), and,
rarely, the interosseous artery (1 in 506: R. Quain). In another set of cases, the
large branch gives origin to the subscapular, the two circumflex, and the two
profunda arteries of the arm ; but sometimes only one of the circumflex, or only
one of the deep humeral arteries, arises from it. In the second class of cases the
divisions of the brachial plexus of nerves surround the common trunk of the
branches instead of the main vessel. This disposition may with probability be
explained by supposing that the trunk of the branches was originally the brachial
artery, but that in early life it had become obstructed below, and that there had
become developed in its place, as an apparent brachial artery for the supply of
the lower portions of the limb, a vas aberrans, such as is sometimes seen arising
from the brachial artery, and uniting with one of its branches.

The superior thoracic artery is so frequently given off by the acromio-thoracic,
that some anatomists have described that as the normal arrangement, giving the
common trunk the name of thoracic axis, The long thoracic artery often rises
from the acromio-thoracic, or is replaced by enlargement of the normal branches
of that artery, and not unfrequently is given off by the subscapular.

The dorsalis scapule sometimes springs directly from the axillary artery.

The posterior circumflex artery is sometimes removed from the axillary to the
superior profunda branch of the brachial, in which case it ascends behind the
tendons of the latissimus dorsi and teres major. In another class of cases not
quite so numerous, the posterior circumflex gives off one or more branches usually
derived from other sources: as for example (placing them in the order of
frequency), the anterior circumflex, the superior profunda, the dorsal scapular,

THE BRACHIAL ARTERY. 399

‘the anterior circumflex and superior profunda together, or some other rarer com-
ination of those vessels. The posterior circumflex is sometimes double; and so
is the anterior, but more seldom.

SURGICAL ANATOMY OF THE AXILLARY ARTERY.

This artery is usually tied in the third part of its course. The limb having been
carried away from the chest, an incision three inches long is made about midway
‘between the folds of the axilla and in the direction of the axis of the limb. On
cutting through the deep fascia, the vein, artery and brachial nerves are exposed.
‘The vein is internal, and the artery is partly surrounded by the nerves. The
ligature is passed from within outwards. In the rest of its course the artery is
so deeply placed and in such close relations with the vein and nerves that an
operation on the third part of the subclavian is both easier and more successful.

BRACHIAL ARTERY.
‘The brachial or humeral artery, the continuation of the axillary,

Fig. 261.—Dissection or THE AxILLA AND InstpE oF THE ARM TO SHOW THE
AXILLARY AND BracutaAn Vessets (from R. Quain) 4}

The greater and lesser pectoral muscles have been divided so as to expose the axillary
vessels : a, the inserted portion of the pectoralis major ; 0, the pectoral portion ; 1, 1,
axillary artery ; +, +, the median nerve formed by the two portions of the plexus which
surround the artery ; 1’, placed on a part of the sheath of the brachial vessels, and 1", on
the lower part of the biceps muscle, points to the brachial artery surrounded by its venz
comites ; 2, 2, axillary vein ; 8, 3, the basilic vein; the upper figure is placed on the
triceps muscle, the lower on the fascia near the junction of the ulnar vein : on the basilic
vein are seen the ramifications of the internal cutaneous nerve ; 4, on the deltoid, and
4’, near the clavicular part of the great pectoral muscle, mark the cephalic vein joining
the acromio-thoracic and through it the axillary vein ; 5, 5, placed on the divided portions
-of the pectoralis minor, point to the origin and branches of the acromio-thoracic artery ;
6, placed on a group of axillary glands, indicates the alar thoracic and subscapular vessels ;
7, placed on the trunk of the axillary vein, points to one of the vene comites of the
brachial vein, which being joined by the other higher up passes into the axillary vein ;
the ulnar nerve is seen passing from below the basilic vein towards the inner condyle ;
near 1, placed on the coraco-brachialis muscle, is seen the musculo-cutaneous nerve before
it passes through that muscle; near 2, placed on the tendon of the latissimus dorsi
muscle, a portion of the nerve of Wrisberg.

400 THE ARTERIES OF THE UPPER LIMB.

extends from the lower border of the posterior fold of the axilla, to
about a finger’s breadth below the bend of the elbow, or to a point
opposite the neck of the radius, where it divides into the radial and
ulnar arteries. The vessel gradually inclines from the inner side to the
fore part of the limb, lying in the depression along the inner border of
the coraco-brachialis and biceps muscles ; and its direction may be
marked out by a line drawn from midway between the folds of the
axilla to the middle point between the condyles of the humerus. To
command the flow of blood through the artery at its upper part, pres-
sure should be directed outwards, while over the lower end of the vessel
the pressure should be made from before backwards.

The brachial artery lies beneath the integument and fascia of the
arm as far as the bend of the elbow, where it sinks deeply in the in-
terval between the pronator teres and supinator longus muscles, and is
covered by the semilunar fascia, a fibrous expansion given from the
tendon of the biceps to the fascia of the forearm. It rests at first on
the long head of the triceps muscle, the musculo-spiral nerve, and the
superior profunda artery intervening ; it then inclines forwards over
the insertion of the coraco-brachialis muscle, and lies thence to its
termination on the brachialis anticus. At its outer side it is in appo-
sition first with the coraco-brachialis, and afterwards and for the greater
part of its length with the biceps, the inner border of one or both
muscles sometimes slightly overlapping it.

Fig. 262. Fig. 262.—Suprrricrat DissEcTION OF THE
Buoop-VEssELS AND NERVES AT THE BEND OF
THE Arm (from R. Quain).

a, two branches of the internal cutaneous
nerve; a’ a", the descending twigs of the same
nerve ; 0, placed over the biceps near its inser-
tion and close to the external cutaneous nerve ;
é', anterior twigs of the same nerve accompany-
ing the median vein ; 1, placed on the fascia of
the arm near the bend of the arm, above the
place where it has been opened to show the lower
part of the brachial artery with its venz comites,
of which one is entire, marked 2, and the other
has been divided; +, is placed between the
artery and the median nerve; 3, basilic vein ;

’, 8, ulnar veins; 4, cephalic vein; 4’, radial
vein; 5, 5, median vein; 3’, 5, median basilic
vein ; 4’, 5, median cephalic vein.

Relation to Veins ——Venee comites
are in close contact with the brachial
artery, short transverse branches of
communication passing from one to
another, so as at many points to encircle
it. Superficial to the aponeurosis, the
basilic vein is placed over or to the inner
side of the artery in the lower half or
: more, or in the whole length of its

se] course, according the level at which

the vein dips down to join the vene

comites ; and at the bend of the elbow the median basilic vein crosses
over the artery, theaponeurotic insertion of the biceps lying between them.

THE BRACHIAL ARTERY, 401

Relation to Nerves. — The median °
nerve descends in contact with the
artery, lying on its outer side at the
axilla, directly in front of it below the
middle of the arm, and on the inner
side at the elbow. Of the other large
branches of the brachial plexus which
are closely connected with the axillary
artery, none continue in the immediate
neighbourhood of the brachial artery
along the arm. The external cvtaneous
and circumflex separate at once from
the vessel in the axilla, the musculo-
spiral soon turns backwards in the
musculo-spiral groove, and the inter-
nal cutaneous and ulnar nerves descend
vertically on the inner side of the
limb.

Fig. 263.—Suprrrictan View or THE ARTERIES
OF THE FRONT OF THE FoRE-ARM, AND Hanp
(from Tiedemann).
a, deltoid muscle ; 2, biceps ; 0’, its semilunar

fascia ; c, scapular head of the triceps; c’, its
internal head ; d, pronator radii teres ; e, flexor
arpi radialis ; f, palmaris longus ; f’, its tendon
spreading in the upper part of the palmar fascia,
from which, on the inner side, the palmaris
brevis muscle is seen rising; g, flexor carpi
ulnaris ; 2, supinator radii longus ; 7, extensor
earpi radialis longior ; 7, extensor ossis meta-
arpi pollicis ; m, flexor digitorum sublimis ;
1, placed on the tendon of the latissimus dorsi,
the lower part of the axillary artery, continued
into the brachial; 2, superior profunda; 3,
inferior profunda ; 4, anastomotic ; 5, near the
division of the brachial artery into ulnar and
radial, points to the origin of the recurrent
radial artery ; 5’, lower part of the radial artery,
where it gives off the superficialis vole, and turns
round the wrist ; 6’, the lower part of the ulnar
artery, near the place where it passes down to
form the superficial palmar arch ; 7, the super-
ficialis vole, which joins it; 8, 8, 8, §&, first,
second, third, and fourth digital branches of the
superficial arch to the inside of the little finger,
adjacent sides of the 4th and 5th, 3rd and 4th,
and 2nd and 8rd fingers ; 9, radialis indicis ;
on the thumb are seen the two branches of the
princeps pollicis artery.

Brancues. — The brachial artery
gives some small muscular branches,
which are directed outwards and back-
wards to the coraco-brachialis, biceps,
and brachialis anticus ; and the fo!low-
ing larger branches which incline in-
wards :-—

VOL. I, DD

402 ARTERIES OF THE UPPER LIMB.

(a) The superior profunda artery arises from the inner and back
part of the brachial, just below the border of the teres major,
and inclines inwards and backwards, to reach the interval between the
outer and inner heads of the triceps muscle. Accompanied by the
musculo-spiral nerve, it winds round the back of the humerus, in the
spiral groove, under cover of the triceps, and perforating the external
intermuscular septum, reaches the external and anterior aspect of the
bone. There the artery lies deeply in the interval between the
brachialis anticus and supinator longus muscles, considerably dimin-
ished in size by having given off several branches, and descends to the
elbow, where it anastomoses with the recurrent branch of the radial
artery.

Branches.—The superior profunda gives off branches in its first part to the
deltoid, coraco-brachialis, and triceps ; and many to the Jast-named muscle, whilst
it is between it and the bone. In this position it also gives one long branch,
which descends perpendicularly between the muscle and the bone to the back
part of the elbow-joint on the outer side, where it anastomoses with the inter-
osseous recurrent branch; and another which anastomoses on the inner side
with the ulnar recurrent and the anastomotic or the inferior profunda.

(6) The inferior profanda artery of small size, arises from the
brachial artery alittle below the middle of the arm, and is directed to the
back part of the inner condyle of the humerus. Descending in company
with the ulnar nerve, it pierces the intermuscular septum, then lies on
the inner surface of the triceps muscle, to which it gives branches,
and entering the interval between the olecranon and inner condyle, it
terminates by inosculating with the posterior recurrent branch of the
ulnar artery, and with the anastomotic branch of the brachial.

(c) The nutrient artery of the shaft of the humerus is a small branch
given off by the brachial about the middle of the arm, or by one of its
collateral branches. It inclines downwards, enters the oblique canal in
the humerus near the insertion of the coraco-brachialis muscle, and is
distributed in the interior of the bone.

(d) The anastomotic artery is a very constant branch of moderate
size. Arising from the brachial artery about two inches above the bend
of the arm, it is directed transversely inwards on the brachialis anticus
muscle, above the inner condyle of the humerus, and, after perforating
the intermuscular septum, turns outwards behind the humerus, between
the bone and the triceps muscle, and forms with the superior profunda
an arch across the humerus, immediately above the olecranon fossa
(arcus dorsalis humeri posticus,—Haller). In front of the humerus the
anastomotic artery furnishes a branch which ramifies in the pronator
teres, and anastomoses with the anterior ulnar recurrent branch.
Behind the inner condyle another offset joins with the posterior ulnar
recurrent, and behind the humerus several branches are given to the
joint and the muscle,

Varieties.—From their comparative frequency, and surgical interest, the
peculiarities of the brachial artery, especially those which affect its trunk,
deserve particular attention.

Course.—The brachial artery sometimes lies in front of the median nerve,
instead of behind it.

The brachial artery has been seen, though rarely, to descend, accompanied by
the median nerve, towards the inner condyle of the humerus. and regain its
usual position at the bend of the elbow by passing forwards underneath a fibrous

VARIETIES OF THE BRACHIAL ARTERY. 403

arch, from which the pronator teres in those cases arises, and which descends to
the inner condyle from the occasional prominence called the supra-condylar

Fig. 264.—Drssrcrion oF THE RicHt ARM, SHOW-
ING AN EXAMPLE OF HIGH SEPARATION OF THE
Raprat ARTERY FROM THE BRACHIAL, AND AN
ENLARGED MzpIAN ARTERY IN THE Fors-
arM (from Tiedemann). $¢
1, on the tendon of the latissimus dorsi, points

to the upper part of the brachial artery ; 2, the
brachial artery after giving off the radial ; 3, the
radial rising in the upper third of the arm and
descending in its usual situation in the fore-arm ;
3, its superficial volar branch; 4, the ulnar
artery in its usual course, forming at 5, the
superficial palmar arch, from which three of the
palmar digital arteries and the princeps pollicis
take origin ; the radial supplying the branches
to the index finger and one side of the middle
finger ; 6, the superior profunda branch of the
brachial artery ; 7, muscular branches; 8, anas-
tomotic ; 9, recurrent radial ; 10, anterior inter-
osseous giving an unusually large median branch
which descends over the wrist to unite with the
superficial palmar arch,

process. Sometimes this disposition occurs
without the development of any bony promi-
nence.

As an extremely rare condition, the artery
has been found divided into two vessels near
its commencement, the artery being single
above and below.

In a very few cases the three arteries of
the fore arm, radial, ulnar, and interosseous,
have arisen together from the end of the
brachial trunk, at the usual distance below
the elbow.

High division —The most frequent change
from the ordinary arrangement of the
brachial artery is connected with its division
into terminal branches.

Out of 481 examples recorded by Richard
Quain from observations made, some on the
right and some on the left side of the body,
the vessel was found in 386 to divide at its
usual position, a little below the elbow-joint.
In one case only (and that complicated by
another peculiarity, viz., the existence of a
vas aberrans proceeding from the axillary to
the radial), was the place of division lower
than usual, being between two and three
inches lower than the elbow-joint. In 64
cases the brachial artery divided above the
usual point, at various heights upwards to
the lower border of the axilla. The branch
prematurely separated from the rest of the
trunk in an early division, is, in the pro-
portion of nearly three cases out of four,

404 ARTERIES OF THE UPPER LIMB.

the radial artery; sometimes the ulnar is the branch given off; that is to
say,a branch corresponding to the ulnar in its distribution below the middle
of the fore-arm separates from a trunk which afterwards divides into the normal
radial artery and the interosseous of the fore-arm, which last is normally derived
from the ulnar artery. Rarely the interosseous of the fore-arm, or a vas aberrans,
is the branch given off. In one instance found in the dissecting room of Glasgow
University, the posterior interosseous artery of the fore-arm was thus given off.

In all cases of the high origin of one or other of the arteries of the fore-arm,
the extent in which the two vessels thus formed run separately must vary accord-
ing to the height at which the main artery divides. The point of division in the
entire number of cases, without reference to the particular branch given off, is most
frequently in the upper, less so in the lower, and least so in the middle third of
the arm. But the early division of the main artery of the upper limb may, as
mentioned in connection with the varieties of the axillary artery, take place
within the axilla, in which case it follows that the brachial portion of the vessel
is replaced, throughout its whole extent, by two separate trunks. In 94 cases out
of 481 observed by R. Quain, or about one in five, there were two arteries instead
of one in some part of the arm.

The position of the to arteries, in these cases, is also of much surgical interest.
Usually they are close together, and occupy the ordinary position of the brachial
artery ; but it has been noticed that the radial artery, when thus given off in
the arm, often arises from the inner side of the brachial, then runs parallel with
the larger vessel (the brachial or ulnar-interosseous), and crosses over it, some-
times suddenly, opposite the bend of the elbow, still covered by the fascia. It
has also been found, in a considerable number of instances, to perforate the
fascia, and run immediately under the skin, near the bend of the elbow.

When the a/nar is the branch given off high from the brachial, it often inclines
from the position of the brachial, at the lower part of the arm, towards the
inner condyle of the humerus. This vessel generally lies beneath the fascia as it
des inds, and superficial to the flexor muscles. It is occasionally placed between
theconteguments and the fascia ; and in a single instance was found beneath the
muscles. In one instance occurring in the dissecting-room of the Glaszow
University, the ulnar artery given off from the humeral at the middle of the arm
was observed to descend superficially behind the inner condyle.

The interosscous, after arising from the axillary or brachial artery, is commonly
situated behind the main artery, and, on reaching the bend of the elbow,
passes deeply between the muscles, to assume its usual position in the fore-
arm.

Lastly, when the radial has arisen high in the arm, the residuary portion of the
brachial (wlnar-interosseous) has occasionally been observed descending, accom-
panied by the median nerve, along the intermuscular septum towards the inner
condyle of the humerus, as far as the origin of the pronator teres (which in the
case recorded was found broader than usual), whence it turned forwards under
cover of the muscle, to gain the usual position at the middle of the bend of the
elbow.

The two arteries taking the place of the brachial are in some instances con-
nected near the bend of the arm by an intervening trunk, which proceeds from
the larger (or ulnar-interosseous) artery to the radial or the radial recurrent, and
varies somewhat in its size, form, and course. More rarely the two unusual
arteries are actually re-united.

The aberrant arteries, “vasa aberrantia,’ alluded to above, are long slender
vessels, which arise either from the brachial or the axillary artery, and end by
joining one of the arteries of the fore-arm, or one of their branches. In eight
cases out of nine, observed by Quain, this unusual vessel joined the radial; in
the remaining case it joined the radial recurrent, which arose irregularly from
the ulnar artery. Very rarely the aberrant vessel joinsthe ulnar. This peculiarity
may be regarded, perhaps, as an approach to that condition in which there is
division of the brachial artery and subsequent connection of its two parts by an
intervening branch.

In most cases of the high division of the brachial arteries the condition of the

SURGICAL ANATOMY OF BRACHIAL ARTERY. 405

vessels is not the same in the right and left arms. In 61 bodies in which the
high division existed, it occurred only on one side in 43 ; on both sides, in different
positions, in 13; and on both sides, in the same position, in the remaining 6.

Fig. 265.—ABERRANT ARTERY, SEPARATING FROM THE
BRACHIAL AT THE MIDDLE OF THE ARM, PASSING WITH
THE Mepran NervE THROUGH THE InTERNAL INTER-
MUSCULAR SEPTUM, AND JOINING FARTHER DOWN

THE REGULAR Uunar (from R. Quain). ¢

a, biceps muscle ; 6, triceps ; ¢, c, divided pronator
teres ; d, d, a’, median nerve, diverted from its usual
course, and passing with the aberrant artery through
the internal intermuscular septum ; e, e, ¢, ulnar nerve
in its usual course ; 1, brachial artery, giving off an
aberrant artery at the middle of the arm ; 2, the usual
radial artery; 3, aberrant artery, with the median
nerve twining round it, passing at 3’, through the
internal intermuscular septum ; 3", the same farther
down, and communicating at 4 with the first part of
the normal ulnar artery, 4, given off from the brachial.

Branches.—It has been already mentioned that
the superior profunda may give origin to the pos-
terior circumflex artcry, and that its own origin is
sometimes transferred to a branch arising from the
axillary artery.

The inferior profunda is likewise occasionally
absent, and on that account has not been recog-
nised by some anatomists as a regular branch of
the brachial artery.

The anastomotic artery is sometimes much re-
duced in size, and in that case the inferior profunda
takes its place behind the humerus.

SURGICAL ANATOMY OF THE BRACHIAL
ARTERY.

The brachial artery may be easily reached for
the application of a ligature in any part of its
course. In the middle third of the arm its posi-
tion on the inside of the biceps muscle, where its
pulsation may be felt, is a sufficient guide for the
incision. From the thinness of the parts covering
the artery, however, and the proximity of super-
ficial veins, especially the basilic, the integuments
and fascia must be divided with caution. When
the fascia has been cut through the median nerve
generally comes into view, as it lies in front of
the artery. Occasionally it is found necessary to divide some muscular fibres
before the artery is reached.

In the lower third of the arm, the median nerve being placed to the inner
side, the artery is more fully exposed after division of the fascia, but here care
is necessary in passing the ligature round the artery, to avoid the venze comites
or their communicating cross branches, which cling very closely to the artery.

From the very frequent occurrence of varieties in the mode of division of the
brachial artery into the vessels derived from it, the surgeon must be prepared for
many deviations from the usual position of the parts, and especially for the
presence of two arteries in place of one in the lower third of the brachial region,
In such cases the two arteries are most frequently close together and nearly parallel,
and it will be easy to tie both vessels, should this be rendered necessary by the
nature of the injury for which the operation is performed. But, as will be seen
from what has previously been said of the abnormal forms of the brachial artery,

406

ARTERIES OF THE UPPER LIMB.

\
Wane
\ NY

LANE S\ i335
tS x WN Hes
\N \

y aN

oy

the position of one or both the vessels may
be subject to very considerable variation in
different instances; and in some of these,
while one of the vessels is near the usual
position, the other may be at some distance,
as for example when it is bound down to
the inner condylar line of the humerus.

Big. 266.—Drrp Anterior View or THE AR-
TERIES oF THE ARM, ForE-ARM, AND HAND
(from Tiedemann). 4

The biceps brachii, the pronator teres and mus-
cles rising from the inner condyle, the supinator
longus, the lower part of the flexor longus pollicis
and flexor profundus digitorum, the anterior an-
nular ligament of the carpus and the muscles of
the ball of the thumb, have been removed; n,
pronator quadratus muscle ; 1, lower part of the
axillary artery continued into the brachial ; 2,
superior profunda branch ; 3, inferior profunda ;
4, anastomotic; 5, upper part of the radial
artery and radial recurrent ; 5’, lower part of the
radial artery giving off the superficialis vole
branch ; 5”, the radial artery emerging from be-
tween the heads of the abductor indicis muscle ;
6, 6, the upper part of the ulnar artery with the
anterior and posterior ulnar recurrent branches ;
6’, the ulnar artery approaching the wrist and
descending into the superficial palmar arch which
has been cut short ; 6”, the deep branch of the
ulnar artery uniting with the deep palmar arch ;
7 (marked only on one), three interosseous branches
from the deep palmar arch joining the palmar
digital arteries 8, 8, 8, which have been cut
away from their origin from the superficial arch
to near their division into the collateral digital
arteries ; the ulnar collateral of the little finger
is represented as rising in this instance from the
deep ulnar artery ; 9, placed between the prin-
ceps pollicis and radialis indicis branches of the
radial artery ; 10, lower part of the anterior
interosseous artery passing behind the pronator
quadratus muscle ; 11, anastomosis of the an-
terior carpal branches of the radial and ulnar
arteries with recurrent branches from the deep
palmar arch.

At the bend of the arm the brachial artery
is exposed to the risk of injury from the
operation of venesection, for which the
median basilic vein ismost commonly selected.
This vein lies often exactly in front of the
artery, the semilunar fascia being stretched
between them. Instances are on record in
which the artery has been wounded by the
lancet transfixing the vein and fascia, and a
communication has thus been established be-
tween the vein and artery. On this account
the incision into the vein must be made with
due care, and indeed the median cephalic, if
of sufficient size, may be selected for
veneseciion.

THE ULNAR ARTERY. 407

ULNAR ARTERY.

The ulnar artery, the larger of the two vessels into which the brachial
‘divides, extends along the inner side of the fore-arm into the palm of
the hand, where, joining a branch of the radial, opposite the muscles of
the thumb, it forms the superficial palmar arch. In this course it
inclines at first downwards and inwards, describing a slight curve, the
convexity of which is directed inwards, and passes under cover of the
superficial muscles arising from the inner condyle of the humerus, viz.,
the pronator teres, flexor carpi radialis, palmaris longus, and flexor
sublimis, until it reaches the flexor carpi ulnaris near the junction of
the upper with the middle third of the fore-arm; at this point the
artery comes into contact with the ulnar nerve, which was previously
separated from it by a considerable interval, and changing its direction,
descends vertically with the nerve towards the inner border of the
palm of the hand. Descending along the radial border of the tendon
of the flexor ulnaris muscle, the ulnar artery reaches the outer or radial
side of the pisiform bone, where, still accompanied by the nerve, it
passes over the cutaneous surface of the anterior annular ligament of
the wrist into the palm of the hand. Its disposition in the hand will
be separately described.

In the first half of its course through the fore-arm, the artery is
deep seated, being covered by the muscles arising from the inner condyle
of the humerus which have been already enumerated. About the
middle of the fore-arm it is overlapped by the fleshy part of the flexor
carpi ulnaris ; but below that, it becomes more superficial, being over-
laid by the tendon of the muscle, and covered by the skin, the fascia of
the fore-arm, and a thin layer of membrane by which the vessel is
bound down to the muscle beneath. At first the ulnar artery lies on
the insertion of the brachialis anticus into the coronoid process of the
ulna; then on the flexor profundus in the rest of the fore-arm, and
lastly, on the annular ligament of the carpus. Below the point at
which it emerges from under the flexor carpi ulnaris (or a little below
the middle of the fore-arm), the tendon of that muscle is on its inner
or ulnar side.

Relation to Nerves—The median nerve lies immediately on the inner
side of the ulnar artery at its origin, but being directed down the middle
of the fore-arm it soon passes over the vessel, separated from it at the
point of crossing by the deep head of the pronator teres muscle. As
the ulnar nerve descends behind the inner condyle of the humerus, it is
removed from the ulnar artery by a considerable interval at the upper
part of the fore-arm ; but as the vessel inclines inwards, it approaches
the nerve, and is accompanied by it in the lower half of its course—the
nerve lying close to its inner side. A small branch of the ulnar nerve
descends upon the lower part of the vessel.

Relation to Veins.—'Two veins (venz comites) accompany the ulnar
artery, and are frequently united by branches crossing it. :

BrancHEs.—The ulnar artery gives off in the fore-arm the anterior
and posterior recurrent, the interosseous, and several muscular
branches. At the wrist it gives off the anterior and posterior carpal
branches.

The anterior ulnar recurrent artery, a small branch, arches inwards
and upwards from the upper part of the ulnar artery, in front of the

inner condyle, running on the brachialis anticus muscle, and covered by

408 ARTERIES OF THE UPPER LIMB.

the pronator teres, both of which muscles it partly supplies. On
reaching the front of the condyle, it anastomoses with the inferior
profunda and anastomotic branches of the brachial.

The posterior ulnar recurrent artery, larger than the preceding,
comes off lower down ; but not unfrequently the two vessels arise by a
shortcommon trunk. The posterior recurrent runs inwards and backwards
beneath the flexor sublimis, and then ascends behind the inner condyle.
In the interval between that process and the olecranon it lies beneath
the flexor carpi ulnaris, and passing between the heads of that muscle
along the ulnar nerve, supplies branches to the muscles, to the elbow
joint, and to the nerve itself. This branch communicates with the
inferior profunda, the anastomotic, and, over the olecranon, likewise
with the interosseous recurrent.

ig. 267. Tig. 267.—View or tar Anas-
TOMOSES OF ARTERIES NEAR
THE Hisow-sornt: A, from
BEFORE ; B, FROM BEHINI>
(from R. Quain), +

A. a, brachialis anticus mus-
cle ; 6, external condylar
eminence covered by the supi-
nator radii brevis and the anas-
tomoses of the superior profunds
and radial recurrent arteries ;
c, ulnar nerve; d, median
nerve ; €, musculo-spiral nerve ;
cv’, its posterior interosseous
branch ; its radial branch is
cut short ; f, oblique line of the
radius ; 1, brachial artery ; 2,
radial artery ; 3, ulnar artery ;
4, inferior profunda ; 5, anas-
tomotic ; 6, anterior ulnar re-
current anastomosing with the
anterior descending branches of
the anastomotic; 7, posterior
ulnar recurrent passing up be-
hind the inner condylar emi-
nence to anastomose with the
inferior profunda and posterior
branch of the anastomotic; 8,
spiral branch of the superior
profunda ; 9, placed on the:
tendon of the biceps muscle,
points to the radial recurrent
artery; 10, 10, interosseous
artery and its anterior branch.

B. a, a part of the brachialis anticus muscle ; b, external lateral ligament of the
elbow-joint ; ¢, ulnar nerve ; d, a small part of the musculo-spiral nerve ; 1, superior
profunda artery ; 2, its branch to the triceps muscle ; 3, its spiral branch to the outer
condyle ; 4, its anastomosis with the recurrent radial artery ; 5, recurrent of the posterior
interosseous artery, passing up to anastomose with the preceding and with the anasto-
motic, behind the joint ; 6, inferior profunda ; 7, posterior branch of the anastomotic
artery ; 8, anastomosis of the anastomotic and inferior profunda with the superior pro-
funda and the posterior interosseous recurrent ; 9, posterior ulnar recurrent artery pass-
ing up in the groove of the ulnar nerve to anastomose with the inferior profunda and.
anastomotic.

The interosseous Or Common interosseous artery, the next, and
the largest branch of the ulnar. is a trunk of considerable size, about

INTEROSSEOUS ARTERIES. 409

an inch in length, which arises below the bicipital tuberosity of the
radius, beneath the flexor sublimis, and passes backwards to reach the
upper border of the interosseous ligament, where it divides into the
anterior and posterior interosseous arteries.

The anterior interosseous descends upon the anterior surface of the
interosseous ligament, accompanied by the interosseous branch of the
median nerve and ven comites, and overlapped by the contiguous
borders of the flexor profundus digitorum and flexor longus pollicis.
muscles, It continues its course directly downwards as far as the upper
border of the pronator quadratus muscle, then pierces the interosseous
ligament, and descends to the back of the carpus.

The anterior interosseous artery gives off the following branches :—

(a) The artery of the median nerve, or the median artery, a long slender
branch, which accompanies the median nerve and sends offsets into its substance.
This artery is sometimes much enlarged,and in that case it presents several pecu-
liarities to be hereafter noticed.

(b) Muscular branches to the flexor profundus, flexor longus pollicis, and pro-
nator quadratus muscles.

(c) The nutrient arteries of the shafts of the radius and ulna, which diverging
from one another, enter the oblique foramina in those bones to be distributed to
the medullary membrane in their interior.

(d) An anterior inosculating branch, given off before the artery pierces the
interosseous membrane, and descending beneath the pronator quadratus muscle
to anastomose with the anterior carpal arteries.

(¢) Lerminal twigs inosculating with the posterior carpal arteries,

The posterior interosseous artery passes backwards through the interval
left between the oblique ligament and the upper border of the interos-
seous ligament, and continuing its course downwards along the fore-arm,
between the superficial and deep layers of extensor muscles, gives
branches to them, and reaches the carpus considerably diminished in
size.

In addition to muscular branches, it gives off the following :—

(a) The posterior intcrosscous recurrent. Which passes directly upwards, covered
by the anconeus, to reach the interval between the olecranon and external con-
dyle; at which place it divides into several offsets which anastomose with the
superior profunda and the posterior ulnar recurrent.

(b) Terminal branches, which anastomose with the posterior or terminal branch:
of the anterior interosseous artery, and with the carpal branches of the radial
and ulnar arteries.

Muscular Branches of the ulnar artery are distributed to the
muscles in the course of the vessel along the fore-arm : some of these
perforate the interosseous ligament to reach the extensor muscles.

The posterior ulnar carpal branch, of variable size, arises a little
above the pisiform bone, and winding back under the tendon of the
flexor carpi ulnaris, reaches the dorsal surface of the carpus beneath:
the extensor tendons.

Its branches are the following :—

(a) A branch anastomoses with the posterior carpal artery derived from the
radial, so as to form the posterior carpal arch, and from this arch are derived the
second and third dorsal intcrosscous arteries, which descend on the spaces between
the third and fourth and the fourth and fifth metacarpal bones, and are reinforced
at the upper ends of those spaces by anastomoses with the posterior perforating,
branches of the deep palmar arch.

(») A branch runs along the metacarpal bone of the little finger. Sometimes.

410 ARTERIES OF THE UPPER LIMB.

this metacarpal branch axises as a separate vessel, the posterior carpal being then
very small.

Fig. 268.—AxnnormaL SuperriciAL Uunar ARTERY
RISING HIGHER THAN USUAL FROM THE BracHIaAL
(from R. Quain, and from a preparation in Allen
Thomson’s collection). +

a, biceps muscle covered by the deep brachial fascia ;
b, the same fascia in the fore-arm, which has been
opened in a considerable extent to show the radial artery
subjacent to it ; c, median nerve; d, ulnar nerve; 1
on the biceps muscle, points to the brachial artery after
having given off an ulnar artery higher up, and dividing
at 1’, into the radial artery and a deep vessel correspond-
ing to the interosseous and a part of the usual ulnar ;
2, on the supinator longus muscle, points to the radial
artery ; 3, 3, artery which is given off by the brachial in
the arm, and which descending upon the fascia takes the
place of the ulna at the wrist; 3’, the same continued
into the superficial palmar arch, giving off digital
branches nearly in the usual manner, and joined by a
branch from the radial, 4, the superficial volar ; 5, digital
branches.

The anterior ulnar carpal branch is a very
small artery, which runs on the anterior sur-
face of the carpus beneath the flexor pro-
fundus, anastomoses with a similar offset from
the radial artery, and supplies the carpal bones
and articulations.

Varieties.— Origin.—In the whole number of
cases observed by Richard Quain, the ulnar artery
was found to deviate from its usual mode of origin,
nearly in the proportion of one in thirteen. The
brachial artery was, more frequently than the axil-
lary, the source from which it sprang ; indeed, the
examples of its origin from the main trunk at
different parts appeared to decrease in number in
proportion as the place of origin was higher up the
artery. In one case of high origin of the ulnar
artery the vessel was connected with the brachial
opposite the elbow-joint by means of a transverse
branch (Gruber, Reich. Arch., 1871). See, on this
subject, the description of the varicties of the axillary
and brachial arteries.

Course—The position of the ulnar artery in the
fore-arm is more frequently altered than that of
the radial.

In cases of high origin, it almost invariably de-
scends over the muscles arising from the inner con-
dyle of the humerus, only one exception to this rule
having been met with. (R. Quain, plate 36, fig. 2.)
In one instance where it took this course it divided
just below the elbow into a superficial and deep
branch (Gruber, loc. cit.).

Most commonly it is covered by the fascia of the fore-arm ; but cases also
occur in which the vessel rests on the fascia, and either continues in that position
or becomes subaponeurotic lower down, while the vessel thus disposed is dis-
tributed after the manner of the normal ulnar artery. The vesscl from which

On

SUPERFICIAL PALMAR ARCH. 411

the high ulnar separates is afterwards divided into the radial artery and the
interosseous, the last of which is usually derived from the ulnar; it appears
therefore probable that the abnormal arrangement results from early obstruction
of the ulnar artery below the origin of the interosseous, and the development of
a superficial vas aberrans, which unites the portion of vessel below the obstruc-
tion with the axillary or brachial trunk. The interosseous artery in such cases of
abnormality thus comprises not only the ordinary interosseous branch, but like-
wise the portion of ulnar artery above the obstruction ; and, in accordance with
this view, we find that the recurrent branches are derived from it.

As to size, the ulnar artery presents some peculiarities which, being accom-
panied by deviations of an opposite and compensating character in the radial
artery, will be noticed with that vessel.

Branches.—The anterior and posterior ulnar recurrent branches fzequently arise
by a common trunk. One or both have been seen to arise from the brachial
artery.

The anterior and posterior intcrosscous arteries are occasionally given separately
from the ulnar. The common interosseous trunk has been found to arise above
its ordinary situation, taking origin from the brachial, and even (but more
rarely) from the axillary artery. The anterior interosseous presents some striking
varieties of excess in its branches, usually connected with a deficiency in the
radial or ulnar arteries: the most important of these is enlargement of the
median branch.

Median artcry.—The branch accompanying the median nerve is sometimes
much enlarged, and in such cases may be regarded as a reinforcing vessel. It is
generally a branch of the anterior interosseous, but sometimes of the ulnar ; and
more rarely a median branch has been met with descending from the brachial
artery. Accompanying the median nerve beneath the annular ligament into the
palm of the hand, the median artery ends most frequently by joining the super-
ficial palmar arch, sometimes by forming digital branches, in other cases by
joining digital branches given from other sources.

SUPERFICIAL PALMAR ARCH.

The superficial palmar arch or artery is the continuation of the ulnar
artery into the hand. Changing its course near the lower border of
the annular ligament, this artery turns obliquely outwards across the
palm of the hand towards the middle of the muscles of the thumb,
where it terminates by inosculating with the superficial volar branch of
the radial artery. In its course across the hand, the palmar artery
describes a curve, having its convexity directed towards the fingers,
and extending downwards somewhat lower than a line on a level with
the phalangeal articulation of the thumb.

The superficial palmar artery rests at its commencement on the
annular ligament of the wrist, and slightly on the short muscles of the
little finger ; then on the tendons of the superficial flexor of the fingers,
and the divisions of the median and ulnar nerves, the latter nerve
accompanying the vessel for a short distance. It is covered towards the
ulnar border of the hand by the palmaris brevis, and afterwards by the
palmar fascia and the integument.

BrancHEes.—The branches given off by the superficial palmar arch,
which are generally numerous, are as follow.

(a) The deep or communicating branch arises from the ulnar artery
at the commencement of the palmar arch a little beyond the pisiform
bone, sinks deeply between the flexor brevis and the abductor of the little
finger, and inosculates with the palmar termination of the radial artery,
thereby completing the deep palmar arch.

(6) Small recurrent branches, following a retrograde course towards

412 ARTERIES OF THE UPPER LIMB.

the annular ligament, are given off from the upper or concave side of
the palmar arch.

(c) The digital branches, usually four in number, proceed downwards
from the convexity of the palmar arch to supply both sides of the three
inner fingers, and the ulnar side of the fore finger. The first digital
branch inclines inwards to the ulnar border of the hand, and, after giving
minute offsets to the muscles of the little finger, rans along the inner
margin of its phalanges. The second runs along the fourth metacarpal
space, and at the root of the fingers divides into two branches, which
proceed along the contiguous borders of the ring and little fingers. The
‘third is similarly distributed to the ring and middle fingers ; and the
fourth to the latter and the index fingers. The thumb and the radial
side of the index finger are supplied from the radial artery.

Fig. 269.—Suprrricrat DisskcTroN OF THE LOWER
Part oF THE FornarmM AND THE Hanp, sHow-
Ing THE RapraL AND UuNar ARTERIES, THE
SUPERFICIAL PatMAR ARCH, AND THE ACCOM-
panyine Nerves (from R. Quain). 4}

a, placed on the deep fascia of the forearm, be-
tween the tendons of the palmaris longus and flexor
‘carpi radialis muscles ; 6, points by a line crossing
the pisiform bone to the ulnar nerve ; c, points to the
styloid process of the radius and twigs of the radiat
nerve ; 1, radial artery lying on the flexor longus.
pollicis ; 1’, the radial artery passing behind the
tendons of the extensor ossis metacarpi pollicis
and extensor primi internodii pollicis ; 2, superficialis
vole branch piercing the short muscles of the thumb
and emerging below to join the superficial palmar
arch ; 38, external branch of the princeps pollicis ; 4,
radialis indicis ; a branch from the superficial arch
is seen joining the internal branch of the princeps
pollicis ; 5, ulnar artery lying upon the flexor digi-
torum profundus ; 5’, the same descending on the
anterior annular ligament to form the superficial
palmar arch ; 6, deep branch of the ulnar artery
passing between the abductor and flexor minimi
digiti to join the deep arch, accompanied by the deep
branch of the ulnar nerve ; 7, branch of the super-
ficial arch to the ulmar side of the little finger ; 8,
division of the common branch to the 4th and 5th
fingers ; 9, the same to the 3rd and 4th fingers ; 10,
the same to the 2nd and 3rd fingers ; 7 and 8, are
accompanied by the digital branches of the ulnar
nerve, and 3, 4, 9, and 10, by the branches of the
median nerve.

The digital arteries are placed at first
superficial to the tendons, and then they lie
between them, accompanied by the digital
nerves as far as wne clefts Of the fingers, where they are joined by the
anterior interosseous arteries, branches of the deep arch. On the sides
of the fingers, each artery lies beneath the corresponding nerve, and
gives branches which supply the sheaths of the tendons and the joints,
some of them anastomosing across the front of the bones with similar
branches from the opposite side. At about the middle of the last
phalanx, the two branches for each finger converge and form an arch,

THE RADIAL ARTERY. 413

from which proceed numerous small offsets to supply the matrix of the
nail and all the structures at the tip of the finger.

[The varieties observed in the branches of the superficial palmar arch will be
noticed after the description of the deep arteries of the hand. ]

RADIAL ARTERY.

The radial artery appears by its direction to be the continuation of
the brachial, although it does not equal the ulnar in size. It extends
along the front of the fore-arm as far as the lower end of the radius,
below which it turns round the outer border of the wrist, and descends
to the back of the space between the metacarpal bones of the thumb
and fore finger: there it passes forwards into the palm of the hand, and
crosses towards the inner side, so as to form the deep palmar arch. In
consequence of the changes in its course, the direction and connections
of the radial artery may be separately described in the forearm, on the
wrist, and in the hand.

In the forearm the radial artery, commencing at the point of bifur-
cation of the brachial opposite the neck of the radius, descends at
first somewhat obliquely outwards in a line with the brachial artery,
and then nearly vertically along the outer part of the front of the fore-
arm to the styloid process of the radius. Its course may be indicated
by a line drawn from the middle of the bend of the elbow to the narrow
interval between the trapezium bone and the tendons of the extensors
of the thumb, which can be readily felt on the outer border of the
wrist.

The radial artery is nearer to the surface than the ulnar, and is
covered only by the common integument and fascia, except where it is
overlapped by the fleshy part of the supinator longus, which must be
drawn aside in order to bring the vessel into view. At first it is in
contact with the tendon of the biceps, and is supported by the fatty
tissue contained in the hollow in the front of the elbow, which sepa-
rates it from the short supinator muscle. It then rests in succession
on the insertion of the pronator teres, the thin radial origin of the
flexor sublimis, the flexor pollicis longus, the pronator quadratus, and
the lower end of the radius. It is at this last point that the pulse is
usually felt during life. To the inner side of this vessel lie the pro-
nator teres in the upper part of its course, and the flexor carpi radialis
in the remainder ; and on the outer side, in its whole course along the
fore-arm, is the supinator longus muscle.

Relation to Veins.—The artery is accompanied by venze comites, which
have the usual arrangement of those veins.

Relation to Nerves.—The radial branch of the musculo-spiral nerve is
placed on the outer side of the artery in the middle third of its course.
At the elbow that nerve is separated from the artery by a considerable
interval ; end towards the lower end of the fore-arm it turns back-
wards beneath the tendon of the supinator longus, to reach the dorsal
aspect of the limb, and thus loses all connection with the artery. Some
filaments of the external cutaneous nerve pierce the fascia to reach the
lower part of the artery, which they accompany to the back of the
carpus.

At the wrist the radial artery turns outwards between the styloid
process of the radius and the carpus, beneath the tendons of the

-

414 ARTERIES OF THE UPPER LIMB.

Fig. 270.—Drep Anrerion View or tum Ar-
TERIES OF THE ARM, ForREARM, AnD Hanp
(from Tiedemann). 4

The biceps brachii, the pronator teres and mus-
cles rising from the inner condyle, the supinator
longus, the lower part of the flexor longus pol-
iicis and flexor profundus digitorum, the anterior
annular ligament of the carpus and the muscles
of the ball of the thumb, have been removed ; n,
pronator quadratus muscle; 1, lower part of
the axillary artery continued into the brachial ;
2, superior profunda branch ; 3, inferior pro-
funda ; 4, anastomotic ; 5, upper part of the
radial artery and radial recurrent ; 5’, lower part:
of the radial artery, giving off the superficialis
volx branch ; 5”, the radial artery emerging from
between the heads of the abductor indicis mus-
cle ; 6, 6, the upper part of the ulnar artery with
the anterior and posterior ulnar recurrent:
branches ; 6’, the ulnar artery approaching the
wrist and descending into the superficial palmar
arch which has been cut short; 6”, the deep
branch of the ulnar artery uniting with the deep
palmar arch; 7 (marked only on one), three
interosseous branches from the deep palmar arch
joining the palmar digital arteries 8, 8, 8, which
have been cut away from their origin from the
superficial arch to near their division into the
collateral digital arteries; the ulnar collateral
of the little finger is represented as rising in
this instance from the deep ulnar artery; 9,
placed between the princeps pollicis and radialis.
indicis branches of the radial artery ; 10, lower
part of the anterior interosseous artery passing
behind the pronator quadratus muscle ; 11, anas-
tomosis of the anterior carpal branches of the
radial and ulnar arteries with recurrent branches
from the deep palmar arch.

extensors of the metacarpal bone and
first phalanx of the thumb, and upon
the external lateral ligament of the
wrist-joint, to reach the back of the
carpus. It then runs downwards for
a short distance, is crossed by the
tendon of the extensor of the second
phalanx of the thumb, and reaching
the upper end of the space between the
first and second metacarpal bones,
turns forwards into the palm of the
hand, by passing between the heads of
the first dorsal interosseous muscle.

As it turns round below the end of ©
the radius the artery is deep-seated, |
but afterwards comes nearer to the
surface. It is accompanied by two
veins and by some filaments of the
external cutaneous nerve, and is crossed
by subcutaneous veins and by filaments
of the radial nerve.

BRANCHES OF THE RADIAL ARTERY. 415

Fig. 271.—Artertes or THE OuTER AND Back
Part oF THE ArM anp Hanp, SuPERFICIAL
View (from Tiedemann). 3

a, deltoid muscle ; 6, external humeral head of
triceps ; c, biceps brachii; d, brachialis anticus ;
e, supinator longus ; jf, extensor carpi radialis
longior ; g, brevior; hk, extensor communis digi-
torum and extensor minimi digiti; 72, extensor
carpi ulnaris ; &, anconeus ; /, flexor carpi ulnaris ;
m, extensor ossis metacarpi pollicis; n, extensor
primi internodii pollicis ; 0, tendon of the extensor
secundi internodii pollicis; 1, 1, branches of
superior profunda artery appearing between the
triceps and brachialis anticus, and descending on
the outer supracondylar eminence to anastomose
with the branches of the recurrent radial artery ;
2, above the posterior annular ligament points to
the posterior carpal branch of the anterior inter-
osseous artery ; 3, posterior carpal branch of the
ulnar artery ; 4, radial artery talking its course be-
tween the outer lateral ligament of the wrist-joint
and the tendons of the extensor muscles before
passing near 5, between the two heads of the
abductor indicis : beneath the extensor tendons
is seen the posterior carpal arch, giving the third
and fourth dorsal imterosseous arteries ; 6, the
inner dorsal artery of the thumb; 7, the outer
dorsal artery of the index finger, and between 7,
and 7’, the remaining dorsal digital vessels in the
spaces between the heads of the metacarpal bones,
near their communications with the palmar digital
vessels.

Brancuns.—The branches of the ra-
dial artery may be arranged according as
they are given off in the fore-arm, on the
wrist, and in the hand.

A. The branches which arise from the
radial in the fore-arm are the radial
recurrent, the muscular branches, the
anterior carpal, and the superficial volar.

The radial recurrent artery, which
varies much in size, arches upwards from
the radial soon after its origin, running
between the branches of the musculo-
spiral nerve. It first lies on the supi-
nator brevis, and then on the brachialis
unticus, being covered by the supinator
longus. In front of the outer condyle,
and in the interval between the two last
muscles, it anastomoses with the termi-
nal branches of the superior profunda.

From the lower or convex side of this ar-
tery are given off several branches; one, of
considerable size, to the supinator and exten-
sor muscles, and some beneath the latter to
anastomose with the posterior interosseous
branche... It also supplies the supinator
brevis, and brachialis anticus in part,

416 ARTERIES OF THE UPPER LIMB.

The anterior radial carpal is a small branch which arises from the
radial artery, near the lower border of the pronator quadratus, and runs
inwards in front of the radius. It anastomoses with the anterior ulnar
carpal artery, so as to form an arch above and in front of the radio-
carpal articulation, from which branches descend to supply the joints at
the wrist.

The superficial volar (ramus superficialis vole), arising from the
radial artery, near the place where it leaves the front of the fore-arm,
passes onwards into the hand. In size it is variable ; in most instances
it is very small, and ends in the muscles of the thumb ; but in others
it attains considerable size, and crossing those muscles, terminates by
inosculating with the radial extremity of the superficial palmar arch,
which it thus completes.

Several unnamed muscular branches are given by this part of the
artery to the muscles on the fore part of the arm.

B. The branches which arise from the radial artery behind the
wrist are, the posterior carpal, the metacarpal, the dorsal arteries of the
thumb, and the dorsal artery of the index finger.

Fig. 272. Fig. 272.—Drne View or THE ARTERIES OF THE
Wrist AND Hanp, FROM BEFORE (from R.
Quain). 3

The anterior annular ligament of the carpus has
been divided and the lower parts of the common
flexors and flexor of the thumb have been removed ;
portions of these tendons are represented as turned
down upon the fingers with parts of the lumbricales
muscles ; the superficial palmar artery is removed,
and the interossei muscles are exposed. a, ulnar
nerve ; b, tendon of the flexor carpi ulnaris muscle ;
c, tendon of the flexor carpi radialis ; d, inserted
tendon of the extensor ossis metacarpi pollicis ;
J, radial artery; 1’, its lower part giving off the
anterior carpal and superficial volar branches; 2,
ulnar artery ; 3, anterior interosseous artery before
passing behind the pronator quadratus muscle ; 4,
radial artery, appearing deeply in the palm between
the first and second metacarpal bones and passing
into the deep palmar arch ; 5, deep branch of the
ulnar artery dipping between the abductor and
fiexor brevis minimi digiti to join the deep arch
and accompanied by the deep branch of the ulnar
nerve ; 6, a palmar digital artery, rising from the
first part of the superficial palmar arch; 7, the
princeps pollicis, and 8, the radialis indicis arteries
rising from the radial artery ; 9, 9, 9, interosseous
branches of the deep palmar arch proceeding down
on the interosseous muscles to join the palmar
digital arteries from the superficial arch.

(2) The posterior radial carpal is a
small but constant branch. It arises
beneath the extensor tendons of the thumb,
and running inwards on the back of the carpus anastomoses with the
posterior ulnar carpal branch, completing the arch from which spring the
dorsal interosseous arteries of the third and fourth spaces. It anasto-
moses, also, with the terminal branch of the anterior interosseous of the
fore-arm.

BRANCHES OF RADIAL ARTERY IN THE HAND. 417

(0) The first dorsal interosseous or metacarpal branch arises be-
neath the extensor tendons of the thumb, frequently in common with the
posterior carpal branch, passes to the interval between the second and
third metacarpal bones, communicates with the corresponding perfo-
rating branch of the deep palmar arch, and, descending on the second
dorsal interosseous muscle, anastomoses with the palmar digital branch
at its division between the fingers.

(c) The dorsal arteries of the thumb, two small branches, arising
separately or together opposite the head of the metacarpal bone, run
upon the dorsal aspect of the bones of the thumb, one at the radial, the
other at the ulnar border,

(d) The dorsal artery of the index finger, a very small branch,
arises lower down than the preceding, and sending branches to the ab-
ductor indicis, runs along the radial side of the back of the index finger.

c. The branches derived from the radial after it has entered the
hand, are, the great artery of the thumb, the radial branch of the
index finger, and the large terminal branch, which forms the deep
palmar arch.

(a) The large artery of the thumb (arteria princeps pollicis,— Hal-
ler) arises from the radial, where it is about to turn inwards across the
palm of the hand. It descends in front of the abductor indicis, between
the metacarpal bone of the thumb and the muscles covering it, to the
space between the lower ends of the flexor brevis pollicis. At that point,
and beneath the tendon of the long flexor, it divides into two collateral
branches, which course along the borders of the phalanges, on their
palmar aspect, and unite in front of the last phalanx, to form an arch
similar in arrangement to that on the other fingers.

(b) The radial branch for the index finger generally arises close
to the large artery of the thumb ; but though constantly found, it varies
in size and in its mode of origin. It descends between the abductor
indicis and adductor pollicis muscles, and continues along the radial
border of the index finger, forming the radial collateral branch of that
finger, and anastomosing in the usual manner on the last phalanx
with the ulnar collateral branch derived from the superficial palmar
arch.

Varieties.— Origin.—In the observations of Richard Quain, the radial artery
was found to arise higher up than usual in nearly one case in eight.

Course.—The radial artery more rarely deviates from its usual position along
the fore-arm than the ulnar. It has been found lying upon the fibrous expansion
from the tendon of the biceps, and over the fascia of the fore-arm, instead of
beneath those structures. This vessel has been also observed on the surface of the
long supinator, instead of on the inner border of that muscle. In turing round
the wrist, it has been seen passing over the extensor tendons of the thumb, instead
of within them. As was previously stated (p. 404), the vasa aberrantia occasionally
derived from the brachial or axillary arteries most commonly end by joining the
radial, or one of its branches.

Branches.—The radial recurrent is sometimes very large, or it may be replaced
by several separate branches. When the radial itself arises high up, the recur-
rent artery usually comes from the residual brachial trunk, or sometimes from
the ulnar artery, or more rarely from the interosseous. When given from the
brachial trunk, the radial recurrent has been found crossing beneath the tendon
of the biceps.

The superficial volar branch is small in a considerable number of cases, and is
lost in the short muscles of the thumb, without forming any connection with the

palmar arch, or with any of the digital arteries, In some instances in whichit is
VoL, I. EE

418 ARTERIES OF THE UPPER LIMB,

enlarged, it furnishes one or two digital branches, and along with this the anas-
tomosis with the superficial arch may be absent. The superficial volar branch
occasionally arises as much as an inch and a half higher than usual.

The first dorsal intcrosscous branch (metacarpal), which descends on the second
interosscous space to the cleft between the index and middle fingers, is not
unfrequently so large as to furnish the collateral digital branch to each of those
fingers.

The carpal and interosseous (metacarpal) branches of the radial are sometimes
small, their place being supplied by the perforating offset of the anterior
interosseous, apparently by an enlargement of the ordinary anastomosis between
them.

The radial artery very frequently gives off a communicating branch to the
superficial arch, near the lower border of the adductor pollicis.

Fig 273. Fig. 273.—DissEction or THE Lerr ARM, SHOW-
ING AN ENLARGED Mupran ARTERY WHICH RE-
PLACES THE RapraL AND ULNAR ARTERIES IN
THE supPLY OF Patmar Dricrtan ARTERIES TO
HALF THE Fincers (from Tiedemann). +

1, lower part of the brachial artery ; 2, radial
artery, not giving any Sera volar branch ; 3,
recurrent radial branch; 4, ulnar artery passing
superficially over the wrist and supplying at 4’,
digital arteries to half the hand; 5, the enlarged
median artery passing in front of ‘the annular liga-
ment of the carpus, and supplying 5’, digital vessels
to the outer half of the hand,

DEEP PALMAR ARCH.

The deep palmar arch, the continuation
of the radial artery, commences at the
upper end of the first interosseous space
between the heads of the abductor indicis,
turns transversely across the palm towards
the fourth metacarpal bone, and imoscu-
lates with the communicating branch of
the ulnar artery. The convexity of the
arch thus formed is directed downwards.
It rests on the interosseous muscles and
on the metacarpal bones immediately
below their carpal extremities, and is
covered by the flexor brevis pollicis, the
flexor tendons of the fingers, and the mus-
cles of the little finger. It is nearer to the
carpus than the superficial arch, and differs
from it in retainine its size almost un-
diminished. It is in part accompanied by
the deep branch of the ulnar nerve, which
runs from the inner end of the arch out-
wards.

Branches.—(a) The recurrent branches (ami
retrogradi—Haller), from the upper concave
side, ascend and anastomose with the branches
from the anterior carpal arch.

(b) The superior perforating branches, three in number, pass backwards through
the upper extremities of the last three interosseous spaces to inosculate with the
dorsal interosseous arteries.

DESCENDING THORACIC AORTA. 419

(c) The palmar interosseous arteries, usually three in number, but very liable to
variation, lie in front of the interosseous spaces, supply the muscles there, and
anastomose at the clefts of the fingers with the digital branches from the super-
ficial arch.

It is by an enlargement of these small vessels that the deep palmar arch some-
times supplies the corresponding digital arteries in the absence of those usually
derived from the superficial arch.

Varieties of the Arteries of the Hand.—The arteries of the hand frequently
vary from their usual mode of distribution.

(a) By far the larger number of deviations consist of a deficiency in either the
radial or ulnar system of arteries, accompanied by a corresponding increase in
the other ; and it may be observed that the defect is much more commonly on
the part of the superficial, and the increase on the part of the deep set.

(») In the second and smaller class of variations a deficiency in one or other
of the two systems is supplied, either by the enlargement of branches which
descend in front of the limb, as the superficial volar (from the radial), or the
median artery (from the anterior interosseous, as shown in fig. 273), or by the
enlargement of a metacarpal branch (from the radial) on the back of the hand.

In illustration of these general remarks, the following modes of arrangement
of the vessels may be mentioned :—

In the greater number of cases the superficial palmar arch is diminished, and
gives off fewer digital branches than usual. Generally only one branch is wanting,
viz., that which supplies the adjacent sides of the fore and middle fingers ; but
sometimes two or three branches are absent, or even all four, as when the ulnar
artery, after giving branches to the short muscles of the little finger, ends in the
deep palmar arch. In the last-mentioned case, which is rare, it is obvious that
the superficial arch is altogether wanting.

These various deficiencies in the superficial palmar arch and its branches are
usually compensated for by an enlargement of the deep arch, the palmar inter-
osseous branches of which, being increased in size, divide at the clefts of the
fingers, and form such collateral digital branches as are not derived from the
usual source. But a defective superficial arch may, as before mentioned, be
reinforced from other vessels, viz., from the superficial volar, from an enlarged
median artery, or from a large metacarpal branch.

It sometimes, but more rarely, happens, that the radial system of vessels is
deficient ; in which case the superficial arch (which belongs to the ulnar
system) may supply all the digital arteries to the thumb and fingers, or one of
these may be derived from the superficial volar, the median, or the radial
interosseous artery.

DESCENDING THORACIC AORTA.

From the point at which its arch is considered to termmate—the
lower margin of the third dorsal vertebra, the aorta descends along the
fore part of the spine to the fourth lumbar vertebra, where it divides
into the common iliac arteries. The direction of this part of the vessel
is not vertical, for as it follows the bend of the spine, upon which it
rests, it is necessarily concave forwards in the dorsal region, and convex
forwards in the lumbar. Again, as its commencement is at the left
side of the bodies of the vertebrae, and its termination also inclined
a little to the left, whilst about the last dorsal vertebra the vessel is
nearly in the middle line, there is produced another slight curve,
the convexity of which is to the right side. Within the thorax, where
the offsets are small, the aorta diminishes only slightly in size ; in the
abdomen the diminution is considerable, in consequence of large
branches being furnished to the viscera of that cavity.

That part of the descending aorta which is situated in the thorax, is

EE 2

420 THE THORACIC AORTA.

called the THORACIC AORTA; it extends from the lower border of the
third dorsal vertebra on the left side, to the opening between the crura of
the diaphragm in front of the last dorsal vertebra. It lies in the back
part of the interpleural space or posterior mediastinum, being placed
before the spine and behind the root of the left lung and the pericardium :
on the left side it is in contact with the corresponding pleura and lung,
and close on the right side are the azygos vein, the thoracic duct, and
the cesophagus. The cesophagus, however, towards the lower part of
the thorax, is in front of the artery, and near the diaphragm gets some-
what to the left side. The left or small azygos vein crosses behind the
thoracic aorta.

The branches derived from the thoracic aorta are numerous, but
small. They are distributed to the walls of the thorax, and to the
viscera contained within it—the latter bemg much the smaller and_least
numerous branches.

A. BRANCHES TO THE VISCERA :—

The pericardiac branches are some very small and irregular vessels
which pass forwards and ramify on the pericardium,

The bronchial arteries are the proper nutritious arteries of the
substance of the lung: they accompany the bronchial tubes in their
ramifications through that organ, and they also supply the bronchial
glands, and in part the cesophagus. These vessels vary frequently in
number, and in their mode of origin. The bronchial artery of the
right side arises from the first aortic intercostal artery, or by a common.
trunk with the left bronchial artery from the thoracic aorta ; on the
left side there are generally two bronchial arteries, both of which arise
from the thoracic aorta, one near the commencement of that trunk, and
the other, named inferior bronchial, lower down. Each artery is usually
directed to the back part of the corresponding bronchus, along which it
runs, dividing and subdividing with the successive bronchial ramifica-
tions in the substance of the lung.

Varieties.—The place of origin of the bronchial arteries is liable to much
variation. The artery of the right side has been found to arise singly from the
aorta, from the internal mammary, or from the inferior thyroid. The bronchial
arteries of the two sides have been seen to arise by a common trunk from the
subclavian. (Haller.) Two common trunks, each furnishing a branch to the
right and left lungs, have been observed in a single case to descend into the
thorax after arising, one from the internal mammary, and the other from the
superior intercostal artery. (R. Quain, pl. 26, f.5.) In some cases they arise
from the under surface of the arch, instead of from the thoracic aorta. Instances
occur of two distinct bronchial arteries for each lung.

The esophageal arteries are variable in size and number. There
are usually four or five, which arise from the fore part or right side of
the aorta, and run obliquely downwards upon the cesophagus, supplying
its coats.

Their lower branches anastomose with the ascending offsets of the coronary
artery of the stomach and with the phrenic artery, while their upper branches.
communicate with those of the inferior thyroid artery.

Posterior mediastinal branches of the aorta, small and irregular,
supply the glands and loose tissue of the posterior mediastinum.

B. PARIETAL BRANCHES TO THE THORAX.

The intercostal arteries arise from the posterior part of the aorta,

THE INTERCOSTAL ARTERIES, 421

and run outwards upon the bodies of the vertebrae, to reach the inter-
costal spaces. They are usually ten in number—the upper intercostal

Fig. 274.—View OF THE Fig. 274.
THoracic AND UPPER
Part or THE ABDOMINAL
Aorta, &. Z
For the general descrip-

tion of this figure, see p.

349. The following numbers

indicate the branches of the

aorta; 1, placed between
the origins of the right and

left coronary arteries; 2,

innominate; 3, left carotid ;

4, left subclavian ; 5, bron-

chial; 6, 6, cesophageal ; 7,

7, intercostal arteries (sixth

and seventh); 8, inferior

phrenic; 9, celiac axis; 10,

below the superior mesen-

teric and opposite the origin

of the renal arteries; 11,

11, two of the lumbar ar-

teries.

space, and occasionally
also the second, being
supplied by the supe-
rior intercostal branch
of the subclavian ar-
tery. Owing to the
position of the aorta to
the left side of the
spine, the right aortic
intercostals cross over
the front of the verte-
bree, furnishing small
ranches to their inte-
rior, and are longer
than the arteries of
the left side. ‘The
vessels of both sides
pass outwards behind
the pleura, and are
crossed by the sym-
pathetic nerve: those
of the right side also
pass behind the ceso-
phagus, the thoracic
duct, and the azygos
vein.

In each intercostal
space the artery, pass-
ing outwards more ho-
rizontally than the ribs, crosses the space obliquely, so as to gain the
lower border of the upper rib near its angle. It lies upon the deep

Va Wlitiaa)

422 THE THORACIC AORTA.

surface of the external intercostal muscle, and in the back of the space
is separated from the pleura by a fascia only, but further outwards it
lies between the two layers of intercostal muscles. Extending forwards
in contact with the rib above, it finally anastomoses with one of the
anterior intercostal branches derived from the internal mammary
artery, and with the thoracic branches of the axillary artery.

The first of the aortic intercostal arteries has an anastomosis with
the superior intercostal proceeding from the subclavian artery ; and
the last three are prolonged into the abdominal muscles, where they
communicate with the epigastric artery in front, with the phrenic
arteries at the side, and with the lumbar branches of the abdominal
aorta lower down.

Each intercostal artery is accompanied, as it runs outwards between
the ribs, by a corresponding vein, and by one of the dorsal nerves ; the
vein usually being uppermost, and the artery next below it.

Branches.—(a) The posterior or dorsal branch of each intercostal artery passes
backwards to the inner side of the anterior costo-transverse ligament, along with
the posterior branch of the corresponding spinal nerve ; and, having furnished
an offset to the spinal canal, reaches the muscles of the back, and divides into
an internal and an external branch. The internal branch is directed towards.
the spinous processes, on or through the multifidus spine, and ramifies in the
musclesand theskin. The external branch turns outwards under the longissimus
dorsi, and is distributed between that muscle and the sacro-lumbalis ; some twigs
reach the superficial muscles and the integuments.

The spinal branches of the aortic intercostal arteries are distributed partly to
the cord and its membranes, and partly to the bones, in the same manner as the
spinal branches of the lumbar arteries, to the description of which the reader is
referred.

(b) The collateral intercostal branch, long and slender, arises near the place
where the main trunk comes in contact with the upper rib of the space, and
inclining downwards approaches the border of the lower rib, supplying the bone
and the intercostal muscles, and anastomosing in front with an anterior inter-
costal branch of the internal mammary artery. There are thus in each inter-
costal space two terminal branches of the intercostal arteries communicating with
the branches of the internal mammary.

Varieties.—The number of the intercostal arteries is subject to much varia-
tion: the third, fourth, and fifth vessels may be entirely absent upon one
side, the corresponding spaces being supplied from neighbouring arteries. Two
arteries frequently arise from the aorta by a single stem. In this way the first
lumbar artery is sometimes conjoined with the twelfth intercostal (Henle).

ABDOMINAL AORTA.

The aorta, after having passed the diaphragm, is thus named. It
commences on the front of the last dorsal vertebra, and terminates

Fig. 275.—View or THE Aspommnan Aorta AND ITS Principal Brancurs (from

Tiedemann). +

a, ensiform portion of the sternum ; }, vena cava inferior passing through the tendon
of the diaphragm ; c, the esophagus passing through the muscular portion ; d and e, ten-
dinous parts of the right and left crura; f, 7’, the right and left kidneys with their supra-
renal bodies ; g, 9’, the ureters ; h, the upper part of the urinary bladder ; 2, 2, the right
and left vasa deferentia passing up from the bladder to the internal inguinal apertures ;
k, the rectum, divided and tied near its upper part; 1, 1, the abdominal aorta ; 1’, the
middle sacral artery ; 2, 2’, the right, 8, 3’, the left inferior phrenic arteries, represented
as arising by ashort common stem from the front of the aorta immediately below the
meeting of the crura of the diaphragm ; 4, the trunk of the coeliac axis ; 5, the superior
mesenteric artery ; 6, 6, the renal arteries ; 6’, 6’, the suprarenal arteries arising partly

THE ABDOMINAL AORTA. 423

from the aorta and partly from the inferior phrenic ; 7, placed on the front of the aorta
below the origin of the spermatic arteries; 7, 7’, placed on the psoas muscles, point to
the right and left spermatic arteries as they descend to the internal inguinal apertures ;
8, inferior mesenteric artery ; 9, lumbar arteries, of which the lowest is here represented
as proceeding from the middle sacral artery ; 10, common iliac arteries ; 11, between
the external and internal iliac arteries ; 12, left epigastric artery ; 13, circumflex iliac ;
14, branches of the ilio-lumbar.

Fig. 275

424 THE ABDOMINAL AORTA,

below by dividing into two trunks, named the commion iliac arteries.
The bifurcation usually takes place about half way down the body of
the fourth lumbar vertebra, a little to the left of the middle line; a
point which is nearly on a level with a line drawn from the one crista
ilii to the other, and opposite the left side of the umbilicus.

The anterior surface of the abdominal aorta is successively in apposi-
tion with the pancreas and the splenic vein, the left renal vein, the
third portion of the duodenum, and the peritoneum. ‘The vena cava
lies along its right side, the right crus of the diaphragm being inter-
posed at the upper part of the abdomen ; close to the same side are the
thoracic duct and the azygos vein, which are placed between the aorta
and the right crus of the diaphragm. The aorta is also covered in
front by meshes of nerves derived from the sympathetic, and numerous
lymphatic vessels and glands.

BraNncHES.—The abdominal aorta gives numerous branches, which
may be divided into two sets, viz., those which supply the viscera, and
those which are distributed to the walls of the abdomen. The former
consists of the coeliac artery, the superior mesenteric, the inferior me-
senteric, the capsular, the renal, and the spermatic arteries ; whilst in
the latter are included the phrenic, the lumbar, and the middle
sacral arteries. The first three of the visceral branches are single
arteries.

Varieties. —Place of Division.—In more than three-fourths of a considerable
number of cases, the aorta divided either upon the fourth lumbar vertebra, or
upon the intervertebral disc below it ; in one case out of nine it was below, and in
about one out of eleven above the spot thus indicated. In ten bodies out of every
thirteen, the division of the great artery took place within half an inch above or
below the level of the iliac crest ; and it occurred more frequently below than
above the fourth intervertebral space. (R. Quain., op. cit. p. 415.) An instance
of bifurcation immediately below the origin of the right renal artery is recorded
by Haller (Disputat. Anatom. t. vi. p. 751.)

Unusual Branch.—aA very remarkable case is recorded of the existence of a
large pulmonary branch which arose from the abdominal aorta, close to the cceliac
artery, and after passing upwards through the esophageal opening in the dia-
phragm, divided into two branches, which were distributed to the lungs near their
bases. (Referred to by R. Quain in his work “ On the Arteries,” p. 416.)

A.—VISCERAL BRANCHES OF THE ABDOMINAL AORTA.

The CELIAC ARTERY or AXIS, a short and wide vessel, arises from the
aorta close to the margin of the diaphragm. It is directed forwards
nearly horizontally, and is not more than half an inch long. It is
behind the small omentum, and lies close to the left side of the lobulus
Spigelii of the liver, and above the pancreas, the two semilunar ganglia
being contiguous to it, one on each side. This artery divides into three
branches, viz., the coronary artery of the stomach, the hepatic and the
splenic, which separate simultaneously from the end of the artery like
radii from an axis.

Varieties.—The celiac avis is occasionally partly covered at its origin by the
diaphragm. It may be longer than usual, in which case its branches are not given
off together; or it may be entirely wanting, the coronary, hepatic, and splenic
arteries arising separately from the aorta. In some cases the coeliac artery gives
off only two branches at its division (the coronary and the splenic). the hepatic
being supplied from another source. Rarely, it gives more than three branches

THE CORONARY AND HEPATIC ARTERIES. 425

to the viscera, the additional vessel being a second coronary, or a separate gastro-
ducdenal artery. One or both phrenic arteries are sometimes derived from this
trunk. Cases have been met with in which a connection existed between the
cceliac axis and the superior mesenteric artery close to their origin.

1. The coronary artery of the stomach, the smallest of the three
visceral branches derived from the coeliac artery, inclining upwards and
to the left side, reaches the cardiac orifice of the stomach, and then
proceeding along the smaller curvature of the stomach, from left to
right, gives branches to both sides of that viscus and inosculates with
the pyloric branch of the hepatic artery.

Where it first reaches the stomach, this artery sends upwards asophageal
branches, which anastomose with the aortic cesophageal arteries. The branches
to the stomach descending on the fore and back part of the organ, anastomose
with branches from the arterial arch on the great curvature,

Varieties.—The coronary artery of the stomach is sometimes given off directly
from the aorta: and is occasionally replaced by two separate vessels. It some-
times furnishes an additional hepatic artery.

2. The hepatic artery is in the adult intermediate in size between
the coronary and splenic arteries, but, in the foetus, it is the largest of
the three. The main part of this vessel inclines upwards and to the
right side, between the layers of the small omentum, and in front of the
foramen of Winslow, towards the transverse fissure of the liver; and
in this course it lies upon the vena portee and to the left of the bile-
duct.

Near the transverse fissure of the liver, the hepatic artery divides
into right and left branches, which supply the corresponding lobes of
that organ. The /eff, the smaller division, lying in front of the vena
porte, diverges at an acute angle from the other branch, and turns out-
wards to reach the left extremity of the transverse fissure of the liver,
where it enters that organ.

The right branch inclines outwards to the right extremity of the
transverse fissure, and divides into two or three branches before entering
the liver. The ramifications of the hepatic artery in the liver accom-
pany the divisions of the vense portee and hepatic ducts.

BraNcHES.—The named branches of the hepatic artery are as
follow.

(a) The pyloric artery, coming in contact with the stomach at the
upper border of the pylorus, extends from right to left along the smaller
curvature and inosculates with the coronary artery. It is sometimes a
branch of the gastro-duodenal.

(b) The gastro-duodenal artery, of considerable size, separating from
the hepatic artery before that vessel ascends in the small omentum,
descends behind the duodenum, near the pylorus, and reaches the lower
border of the stomach; there it gives off the superior pancreatico-
duodenal branch, and its remaining part, which receives the name of
right gastro-epiploic, runs from right to left along the great curvature
of the stomach, between the layers of the great omentum, and finally
inosculates with the left gastro-epiploic derived from the splenic
artery.

The gastro-epiploic artery gives branches upwards to both surfaces of the
stomach, and long slender vessels downwards to the omentum.

426 ARTERIES OF THE ABDOMEN.

Fig. 276.

Vig. 276.—Tue Anvenres or THE Stomacu, Liver, anD OMENTUM

(from Tiedemann). 4

The liver is turned up so as to show its lower surface with the portal fissure, and the
vessels and ducts entering it. a, the right lobe of the liver; 6, the left lobe; c¢, the gall-
bladder; c’, the biliary or hepatic ducts; ¢", the ductus communis choledochus; d, the
front of the antero-posterior fissure and the round ligament; e, the cardiac orifice of the
stomach; jf, on the great curvature of the stomach near its cardiac end, points to the
spleen; g, the pylorus ; h, the duodenum ; 7, the great omentum ; &, some of the small
intestines in the lower part of the abdomen; 1, upon the trunk of the abdominal aorta
below the root of the inferior phrenic arteries, and above the cceliac axis ; 2, placed on
the meeting of the crura of the diaphragm, the coronary artery of the stomach ; 2’, the
same artery proceeding round the small curvature of the stomach and ending by anaste-
mosis with the superior pyloric ; 3, the main hepatic artery, continued at 3’ as proper
hepatic artery to the liver; 4, superior pyloric artery; 4’, another pyloric branch ; 5,
placed on the main trunk of the vena portve at the place where the hepatic artery and
ductus communis choledochus are in front of it; 5’, branches of the vena porte in the

THE HEPATIC ARTERY. 427
‘
transverse fissure ; 6, gastro-duodenal artery ; 6’, its continuation as the right gastro-
epiploic ; 7, on the left crus of the diaphragm, the splenic artery ; 8, its left gastro-
epiploic branch proceeding round the great curvature of the stomach to communicate with
the right gastro-epiploic artery ; both of these vessels are seen giving long epiploic as
well as gastric branches.

The superior pancreatico-duodenal branch descends along the inner margin of
the duodenum, between it and the pancreas, and, after furnishing several branches
to both these organs, anastomoses with the inferior pancreatico-duodenal from the
superior mesenteric artery.

(c) The cystic artery, given off by the right hepatic when crossing
behind the cystic duct, turns upwards and forwards upon the neck of
the gall-bladder, and divides into two smaller branches, of which one
ramifies between the coats on the depending surface, the other between
the bladder and the liver.

Varieties.—The hepatic artery sometimes arises from the superior mesenteric
artery, or from the aorta itself. Accessory hepatic arteries are often met with,

oY

Fig. 277.—Tur ARTERIES OF THE Stomacn, DuopENuM, PancREAS, AND SPLEEN
(from Tiedemann).

The stomach and liver are turned upwards so as to show their lower surface. The
jejunum is divided at its commencement. a, lower surface of the right lobe of the liver ;
6, left lobe ; c, cardiac orifice of the stomach ; d, pylorus; e, first part, f, second or
descending part, and g, third or lower part of the duodenum ; h, commencement of the
jejunum emerging from behind the superior mesenteric artery ; 7, the head, and &, the
body of the pancreas ; /, the spleen; 1, 1, right and left inferior phrenic arteries passing
from the aorta upon the crura of the diaphragm; 2, placed on the aorta close to the
celiac axis ; 3, 3’, the coronary artery ; 4, common hepatic ; 4’, its right branch ; 4",
cystic branch ; 5, gastro-duodenal giving the inferior pyloric ; 5, on the great curvature
of the stomach, the right gastro-epiploic ; 6, superior pancreatico-duodenal ; 7, commen
splenic ; 7’, proper splenic ; 7”, one of the vasa brevia to the stomach ; 8, 8, left gastro-
epiploic artery uniting with the right on the great curvature of the stomach ; 9, trunk of
the superior mesenteric artery, giving off the inferior pancreatico-duodenal ; 10, inferior
mesenteric.

428 ARTERIES OF THE ABDOMEN.

‘
usually coming from the coronary artery of the stomach. The hepatic artery
has been found to furnish a phrenic branch.

3. The splenic artery, in the adult the largest branch of the cceliac
axis, supplies the spleen, and in part the stomach and pancreas. It
is directed horizontally towards the left side. Waving and often tor-
tuous in its course, it passes, together with the splenic vein which is
below it, behind the upper border of the pancreas, and divides near
the spleen into several branches. The largest of these enter the fissure
in that organ, and are distributed to its substance ; three or four are
reflected towards the bulging end of the stomach, upon which they
ramify.

Branches.—(a) Pancreatic branches, variable in size and number, are given
off whilst the artery is passing along the pancreas, the middle and left part of
which they supply with vessels. One of larger size not unfrequently runs
from left to right in the direction of the pancreatic duct, and is called pancrcatica
sNaqna.

() The splenic branches are the proper terminal branches of the artery ; they
are five or six, or even more, in number, and vary in length and size; they enter
the spleen by the hilus or fissure in its concave surface, and ramify within
that organ.

(c) The short gastric branches (vasa brevia) vary from five to seven in number;
they are directed from left to right, some issuing from the trunk of the splenic
artery, others from its terminal branches: they reach the left extremity of the
stomach, where they divide and spread out between the coats, communicating
with the coronary and left gastro-epiploic arteries.

(2) The left gastro-epiploic artery runs from left to right along the great cur-
vature of the stomach, supplying branches to both surfaces of the stomach and
to the omentum on the left side, and inosculates with the right gastro-epiploic
branch from the hepatic artery.

The superior mesenteric, an artery of large size, supplies the whole
of the small intestine beyond the duodenum, and half of the great
intestine. It arises from the fore part of the aorta, a little below the
eceliac axis. For a short space this artery is covered by the pancreas ;
on emerging from below that gland it descends in front of the duo-
denum near the end, and is thence continued between the layers of the
mesentery. The splenic vein crosses over its root. In the mesentery
the artery at first passes downwards and to the left side, but afterwards
turns towards the right iliac fossa, opposite to which it inosculates with
its own ileo-colic branch.

BrancuEs.—(a) The weferior pancreatico-duodenal, given off under
cover of the pancreas, runs along the concave border of the duodenum,
and J hee with the superior pancreatico-duodenal artery.

(0) The rami intestini tenuis, or intestinal geome Tas supplying the
jejunum and ileum, spring from the convex or left side of the vessel.
They are usually twelve or more in number, and are all included be-
tween the layers of the mesentery. They run parallel to one another
for some distance, and then divide into two branches, each of which
forms an arch with the neighbouring branch. From the first set of
arches; other branches issue, which divide and communicate in the

same way, until finally, after forming four or five such tiers of arches,

each smaller than the other, the ultimate divisions of the vessels pro-
ceed directly to the intestine, spreading upon both sides, and ramifying
in its coats.

THE SUPERIOR MESENTERIC ARTERY. 429

=

i
aA

i ;
Hh J eo)
wy IVY yi

by
I A>7

“)

yi yay

Fig. 278.—Tur Superior Mesenteric ARTERY AND ITS BRANCHES
(from Tiedemann). +

The transverse arch of the colon is turned upwards ; the transverse meso-colon is
dissected so as to expose the duodenum and pancreas at its root ; the small intestines are
thrown towards the left side; a, the descending part of the duodenum ; 6, the lower
part; c, the commencement of the jejunum; c’, c’, the jejunum and ileum; d, the
termination of the ileum in the caput cecum coli; ¢, the cecum ; f, the vermiform pro-
cess ; g, the ascending colon ; A, the transverse arch ; 7, the descending colon,; /, the
pancreas ; 1, the trunk of the superior mesenteric artery ; 1’, the termination of that
vessel where it loops round into-a branch of the ileo-colic artery ; 2, 2, the intes-
tinal branches; 2’, 2’, their loops in the mesentery ; 3, inferior pancreatico-duodenal
branch passing to 3’, to unite with the branch from the gastro-duodenal; 4, the
middle colic branch ; 5, its left colic branch passing at 5’ tounite with the branch of
the left colic of the inferior mesenteric ; 6, its right branch ; 7, right colic and ileo-colic
arteries in one trunk; 8, right colic, uniting by a loop with the middle colic ; 9, the ileo-
colic, uniting with the end of the superior mesenteric artery.

(c) The colic branches arise from the right or concave side of the
artery, and are usually three in number.

430 ARTERIES OF THE ABDOMEN,

1. The zeo-colic artery, the first in order from below upwards, inclines
downwards and to the right side, towards the ileo-colic valve, near which
it divides into two branches: one of these descends to inosculate with
the termination of the mesenteric artery itself, and to form an arch,
from the convexity of which branches proceed to supply the junction of
the small with the large intestine, and the cecum and its appendix ;
the other division ascends and inosculates with the next mentioned
branch. The ileo-colic artery is not always distinct from the termina-
tion of the superior mesenteric.

2. The right colic artery passes transversely towards the right side,
beneath the peritoneum, to the middle of the ascending colon, opposite
to which it divides into two branches, of which one descends to com-
municate with the ileo-colic artery, whilst the other ascends to join in
an arch with the middle colic. This artery and the ileo-colic often
arise by a common trunk.

3. The middle colic artery passes upwards between the layers of the
mesocolon towards the transverse colon, and divides in a manner
exactly similar to that of the vessels just noticed. One of its branches
inclines to the right, where it inosculates with the preceding vessel ;
the other descends to the left side, and maintains a similar communica-
tion with the left colic branch, derived from the inferior mesenteric
artery. From the arches of inosculation thus formed, small branches
pass to the colon for the supply of its coats.

Those branches of the superior mesenteric artery which supply the
ascending colon have a layer of peritoneum only on their anterior
aspect : the others lie between two strata.

Varieties.—The number of the branches of this artery, both intestinal and
colic,is by no means constant. It also frequently gives off accessory branches to
the neighbouring viscera; of these that to the liver is the most common. It
may replace the gastro-duodenal or its chief branch, the right epiploic (Henle),
or it may give accessory pancreatic and splenic branches (Hyrtl). It has also
been seen to give off the left colic and superior hemorrhoidal arteries when the
inferior mesenteric was absent (Fleischmann). A rare anomaly is the presence
of an omphalo-mesenteric artery, arising either from the main stem or from one
of the branches of the superior mesenteric. In one case it ran direct to the
umbilicus where it gave a branch to the urachus (Haller). In another it reached
the anterior wall of the abdomen rather below the umbilicus, and after giving
a branch to the rectus, which anastomosed with the deep epigastric, it ter-
minated by winding round the ligamentum teres, and forming a capillary net-
work on the suspensory ligament of the liver (Hyrtl).

Infericr mesenteric artery.—This artery, much smaller than the
superior mesenteric, supplies the lower half of the colon, and the greater
part of the rectum. It arises from the aorta, between one and two
inches above the bifurcation of that trunk.

The inferior mesenteric artery inclines to the left side in the direction
of the left iliac fossa, from which point it descends between the layers
of the mesorectum into the pelvis, and, under the name of superior
hemorrhoidal artery, runs down behind the rectum. It lies at first
close to the aorta, on its left side, and then crosses over the left common
iliac artery.

BraNxcHEs.—(a@) The left colic artery is directed to the left side
behind the peritoneum, and across the left kidney to reach the descend-

THE INFERIOR MESENTERIC ARTERY, 431

ing colon. It divides into two branches, and forms a series of arches
in the same way as the colic vessels of the opposite side. One of

Fig, 279,—Tue Inrertor Mesznteric ARTERY WITH ITS DISTRIBUTION AND COMMU-
NICATIONS (from Tiedemann). +4

The small intestines with the superior mesenteric artery are turned towards the right
side, the pancreas is exposed, and the large intestine is stretched out : a, 6, the duodenum ;
c, the commencement of the jejunum; d, the small intestine ; e, the ascending colon ; f,
the transverse colon ; g, the descending colon ; h, the sigmoid flexure ; 7, the commence-
ment of the rectum ; /4, the pancreas ; 1, placed on the trunk of the abdominal aorta at
the origin of the renal arteries; 1’, on the same at the origin of the inferior mesenteric ;
1”, near the division into common iliae arteries ; 2, inferior mesenteric, giving off the
left colic ; 3, ascending branch of the left colic ; 4, branches to the descending colon ; 5,
the sigmoid branch ; 6, the superior hemorrhoidal branch ; 7, the trunk of the superior
mesenteric issuing from behind the pancreas ; 8, some of its intestinal branches ; 9, the
middle colic artery ; 10, its left branch forming a loop of communication with the left
colic ; 11, its right branch ; 12, the spermatic arteries.

432 ARTERIES OF THE ABDOMEN,

these two branches passes upwards along the colon, and inosculates
with the descending branch of the middle colic ; whilst the other
descends towards the sigmoid flexure, and anastomoses with the sigmoid
artery.

(b) The sigmoid artery runs obliquely downwards to the sigmoid
flexure of the colon, where it divides into branches ; some of which
incline upwards and form arches’ with the preceding vessel, while others
turn downwards to the rectum and anastomose with the following
branch. Instead of a single sigmoid artery, two or three branches are
sometimes present.

(c) The superior hemorrhoidal artery, the continuation of the inferior
mesenteric, passes downwards over the common iliac artery and vein
into the pelvis behind the rectum, lying at first in the meso-rectum, and
then divides inte two branches which extend one on each side of the
intestine toward the lower end. About five inches from the anus these
subdivide into branches, about a line in diameter, which pierce the
muscular coat two inches lower down. In the intestine, these arteries,
about seven in number, and placed at regular distances from each other,
descend between the mucous and muscular coats to the end of the
gut, where they communicate in loops opposite the internal sphincter,
and end by anastomosing with the middle and inferior hemorrhoidal
arteries.

Varieties.—-Absence of this artery has been noted, its branches being given
off by the superior mesenteric. It has also been found supplying accessory
branches to the liver and kidneys.

Anastomoses on the intestinal tube.—The arteries distributed to the
alimentary canal communicate freely with each other over the whole length of
that tube. The arteries of the great intestine derived from the two mesenteric
arteries, form a range of vascular arches along the colon and rectum,at the
lower end of which they anastomose with the middle and inferior hemorrhoidal
arteries, given from the internal iliac and pudic arteries. The branches from
the left side of the superior mesenteric form another series of arches along the
small intestine, which is connected with the former by the ileo-colic artery.
Farther, a branch of the superior mesenteric joins upon the duodenum with the
superior pancreatico-duodenal artery. The latter, at its commencement, is in a
manner continuous with the pyloric artery; and so likewise, through the
coronary artery of the stomach and its ascending branches, a similar connection
is formed with the wsophageal arteries, even up to the pharynx.

The suprarenal or capsular arteries are two very small vessels which
arise from the aorta on a level with the superior mesenteric artery, and
incline obliquely outwards upon the crura of the diaphragm to reach
the suprarenal capsules, to which bodies they are distributed, anasto-
mosing at the same time with the upper and lower capsular branches
derived respectively from the phrenic and the renal arteries. In the
foetus these arteries are of larger size.

Varieties.—This middle suprarenal artery is often very small, its place being
supplied by the superior and inferior suprarenals. The middle suprarenal some-
times gives off the spermatic artery. This occurs usually on the left, but it
also occurs, though rarely, on the right side (Henle).

The renal or emulgent arteries, of large diameter in proportion to
the size of the organs which they supply, arise from the sides of the

THE RENAL AND SPERMATIC ARTERIES. 433

aorta, about half an inch below the superior mesenteric artery, that of the
right side being rather lower down than that of the left. Each is
directed outwards, so as to form nearly a right angle with the aorta. In
consequence of the position of the aorta upon the spine, the right renal
artery has to run a somewhat longer course than the left, in order to
reach the kidney. The artery of the right side crosses behind the vena
caya, and both right and left arteries are overlapped by the accom-
panying renal veins. Previously to reaching the concave border of the
kidney, each artery divides into four or five branches, the greater
number of which usually lie intermediate between the vein in front
and the pelvis of the kidney behind. These branches, after having
passed deeply into the fissure of the kidney, subdivide and are distri-
buted in the gland, in the manner described in the account of the
structure of that organ.

Branches.—The renal artery, before passing into the glandular substance,
furnishes a small branch to the suprarenal capsule, a second to the ureter, and
several others which ramify in the connective tissue and fat behind the
kidney.

Varieties. —The senal artery may be replaced by two, three, four, or even five
branches ; and the greatest difference as to the origin of these vessels is found
to exist even on opposite sides of the same body. As they usually arise in suc-
cession from the aorta itself, it would seem as if the deviation were merely an
increased degree of that in which the renal artery divides into branches sooner than
usual after its origin. In some cases a renal artery has been seen to proceed
from the common iliac; and in one case, described by Eustachius, from the
internal iliac. Portal found in one instance the right and left renal arteries
arising by a common trunk from the fore part of the aorta. In another case, one
of several arteries arose from the front of the aorta at its bifurcation ; or from
the left common iliac at its origin.

The branches of the renal artery, instead of entering at the hilus, sometimes
reach and penetrate the gland near its upper end, or on its anterior surface.
The right renal artery has been seen to cross the vena cava in front instead of
behind. Supernumerary branches are also frequently found. The most common
are, the diaphragmatic from the inferior suprarenal ; a hepatic branch from the
right renal ; branches to the small and large intestines; the middle suprarenal ;
the spermatic, and various lumbar arteries. Lastly, cases occur, though very
rarely, in which one of the renal arteries is wanting.

Spermatic and ovarian arteries.—The spermatic arteries, two
small and very long vessels, arise close together from the fore part of
the aorta a little below the renal arteries. Hach artery is directed down-
wards and outwards, resting on the psoas muscle ; it crosses obliquely
the ureter and, afterwards, the external iliac artery, and turns forward
to the internal abdominal rg. There it comes into contact with the
vas deferens, and, separating from the peritoneum, passes with the
other constituents of the spermatic cord along the inguinal canal, and
descends to the scrotum, where it becomes tortuous, and reaching the
back part of the testis anastomoses with the artery of the vas deferens,
and finally divides into branches which pierce the fibrous capsule of
the testis.

In the female, the ovarian arteries, corresponding to the spermatic
arteries in the male, are shorter than these vessels, and do not pass out
of the abdominal cavity. The origin, direction, and connections of the
ovarian artery in the first part of its course are the same as in the male;

but at the margin of the pelvis it inclines inwards, and running tortu-
VOL. I. FF

434 ARTERIES OF THE ABDOMEN.

Fig. 280.

Fig. 280,— VIEW OF THE Appomrnat AoRTA AND ITs Principal BRANCHES
(from Tiedemann). 4

For the detailed description of this figure, see p. 422; 6, renal arteries; 6’, 6,
suprarenal arteries arising from the aorta ; other suprarenal arteries are seen pro-
ceeding from the inferior phrenic ; 7, placed on the abdominal aorta below the origin of
the spermatic arteries ; 7, 7’, lower down the same arteries descending on the psoas

muscles and crossing the ureters, that on the left side entering the internal inguinal

THE PHRENIC ARTERIES. 435

aperture along with the vas deferens (i) ; 8, inferior mesenteric artery ; 9, lumbar arte-
ries ; 9’, the lowest lumbar artery rising in this instance from the middle sacral (Ge
10, 10’, right and left common iliac arteries; 11, 11, placed between the external and
internal iliac arteries on each side ; 12, left epigastric artery ; 13, circumflex iliac artery.

ously between the layers of the broad ligament of the uterus, is guided
to the attached margin of the ovary, which it supplies with branches.
Some small offsets can be also traced along the round ligament into
the inguinal canal, and othersalong the Fallopian tube : one, continuing
inwards towards the uterus, joins with the uterine artery.

In early fcetal life the spermatic and ovarian arteries are short, as the testes
and the ovaries are at first placed close to the kidneys, but the arteries become
lengthened as these organs descend to their ultimate positions.

Varieties.—The spermatic arteries occasionally arise by acommon trunk. Two
spermatic arteries are not unfrequently met with on one side; both of these
usually arise from the aorta, though sometimes one is a branch from the renal
artery. A case has occurred of three arteries on one side,—two from the aorta
and the third from the renal.

B.—PARIETAL BRANCHES OF THE ABDOMINAL AORTA.

Inferior phrenic arteries.—The phrenic arteries are two small
vessels, which spring from the aorta, either close together or by a short
common trunk, on a level with the under surface of the diaphragm.
When they arise separately from each other, one is frequently derived
from the cceliac arvery close to its origin, and the other from the
aorta immediately above. They soon diverge from each other, and,
passing across the crura of the diaphragm, incline upwards and outwards
upon its under surface ; the artery of the left side passing behind the
cesophagus, whilst that of the right side passes behind the vena cava.
Before reaching the central tendon of the diaphragm, each of the
arteries divides into two branches, of which one runs forwards towards
the anterior margin of the thorax, and anastomoses with the musculo-
phrenic branch of the internal mammary artery, while the other pursues
a transverse direction towards the side of the thorax, and communicates
with the terminations of the intercostal arteries.

Branches.—Each phrenic artery gives small branches (superior capsular) to the
suprarenal capsule of its own side; the left artery sends some branches to the
cesophagus, whilst the artery of the right side gives off small vessels which reach
the termination of the vena cava, Small offsets descend to the liver between the
layers of the peritoneum.

Varieties.—The phrenic arteries are found to vary greatly in their mode of
origin, but these deviations seem to have little influence on their course and dis-
tribution. In the first place they may arise either separately, or by 2 common
trunk: and it would appear that the latter mode of origin is nearly as frequent
as the former. When the two arteries are joined at their origin, the common
trunk arises most frequently from the aorta; though, sometimes, it springs from
the coeliac axis. When arising separately, the phrenic arteries are given off
sometimes from the aorta, more frequently from the cceliac axis, and occasionally
from the renal; but it most commonly happens that the artery of the right side
is derived from one, and that of the left side from another of these sources.
An additional phrenic artery (derived from the left hepatic) has been met
with.

In only one out of thirty-six cases observed by R. Quain did the phrenic arteries

ray

436 ARTERIES OF THE ABDOMEN.

arise in the mode ordinarily described; viz., as two separate vessels from the
abdominal aorta. (Op. cit. p. 417.)

Lumbar arteries——The lumbar arteries resemble the intercostal
arteries, not only in their mode of origin, but also in a great measure
in the manner of their distribution. They arise from the back part
of the aorta, and are usually four in number on each side. They
pass outwards, each resting on the body of the corresponding lumbar
vertebra, from the first to the fourth, and soon dip deeply under the
psoas muscle. The two upper arteries are likewise under the pillars of
the diaphragm ; and those on the right side are covered by the vena
cava. At the interval between the transverse processes, each lumbar
artery divides into an abdominal and a dorsal branch.

Branches.—(a) The abdominal branch of each lumbar artery runs outwards
behind the quadratus lumborum,—the lowest of these branches not unfrequently
in front of that muscle. Continuing outwards between the abdominal muscles,
the artery ramifies in their substance, and maintains communications with
branches of the epigastric and internal mammary in front, with the terminal
branches of the intercostals above, and with those of the ilio-lumbar and circum-
flex iliac arteries below.

(6) The dorsal branch of each lumbar artery, like the corresponding branch of
the intercostal arteries, gives off, immediately after its origin, an offset, named
spinal, which enters the spinal canal. The dorsal branch then proceeding back-
wards with the posterior primary branch of the corresponding lumbar nerve
between the transverse processes of the vertebree, divides into smaller vessels,
which are distributed to the muscles and integuments of the back.

(c) The spinal branch enters the spinal canal through the intervertebral fora-
men, and, having given an offset which runs along the nerves to the dura mater
and cauda equina, it communicates with the other spinal arteries, and divides
into two branches, which are distributed to the bones in the following manner :—
one curves upwards on the back part of the body of the vertebra above, near to
the root of the pedicle, whilst the other descends in a similar manner on the
vertebra below; and each communicates with a corresponding branch from the
neighbouring spinal artery. As this arrangement prevails on both sides and
throughout the whole length of the spine, there is formed a double series of
arterial arches behind the bodies of the vertebrae, the convexities of which are
turned towards each other. From the arches on opposite sides offsets are directed
inwards at intervals to reinforce a median longitudinal vessel, which extends
along the spine like the single artery on the front of the spinal cord. The arches
are moreover joined together across the bodies of the vertebre by transverse
branches.

From this interlacement of vessels, numerous ramifications are distributed to
the periosteum and the bones.

Varieties.—The lumbar arteries of opposite sides, instead of taking their origin
separately from the aorta, occasionally commence by a common trunk, whose
branches pass out laterally, and continue their course in the ordinary way. Two
arteries of the same side are sometimes conjoined at their origin. On the last
lumbar vertebra, the place of a lumbar artery is often taken by a branch from
the middle sacral artery, and the ilio-lumbar compensates for the absence of the
lumbar vessel amongst the muscles.

MINUTE ANASTOMOSES OF THE VISCERAL AND PARIETAL BRANCHES OF
THE ABDOMINAL AORTA.

The existence of minute anastomoses between some of the visceral branches cf
the abdominal aorta and those supplying the wall of the cavity has been recog-
nised by several anatomists, and various examples have been noticed in the pre-
vious description. These communications have been more distinctly proved and

MIDDLE SACRAL ARTERY. 437

their nature elucidated by W. Turner in a series of experimental injections, made
with a view to their detection, (‘ Brit. and For. Med. Chirug. Review,” July,
1863.)

These anastomoses constitute a well-marked vascular plexus, situated in the
subperitoneal tissue, which Turner calls the suhperitoncal arterial plexus. It
occupies the lumbar region from the diaphragm downwards into the iliac regions
and pelvis, and establishes communication between the parietal vessels and those
of the viscera, chiefly, though not exclusively, through branches of the arteries
of those viscera which are situated behind the peritoneum. It belongs to the
renal and suprarenal arteries, those of the pancreas and duodenum, the cxcum.
and the ascending and descending parts of the colon. It extends also to the
vessels of the rectum, and to the spermatic arteries in their descent through the
abdomen, and into the inguinal canal and scrotum.

In these situations it was found that the injected material (coloured gelatine)
when thrown into the vessels of the viscus, so as to fill them completely,
extended through the subperitoneal plexus in various ways, so as to reach one
or other set of parietal vessels, such as the lumbar, ilio-lumbar, circumflex iliac,
lower intercostal, and epigastric arteries; and in the pelvis, the middle and
lateral sacral arteries ; and in the scrotum, the superficial pudic and perineal
arteries.

The more direct inosculations of the hemorrhoidal arteries on the rectum with
the inferior hemorrhoidal branches of the pubic artery are well known, and the
importance of these and other similar anastomoses, as well as the more extensive
and minute anastomosing plexus investigated by Turner, is obvious, with reference
not merely to the nutrition of the subperitoneal tissue, but also to the debated
question of the influence exerted by local superficial blood-letting on the state of
the vessels of the deeper viscera.

Middle sacral artery—The middle sacral artery, the last of the
branches of the abdominal aorta, is a small vessel about the size of a
crowquill, which arises from the extremity of the aorta just at the
bifurcation. From this point the artery proceeds downwards upon the
last lumbar vertebra and over the middle of the sacrum, as far as the
coccyx, Where it forms small arches of anastomosis with the lateral
sacral arteries.

Branches.—From its anterior surface some small branches come forward
within the fold of the meso-rectum, and ramify upon the posterior surface of
the intestine ; and on each side others spread out upon the sacrum, and anasto-
mose with the lateral sacral arteries, occasionally sending small offsets into the
anterior sacral foramina.

Varieties.—The middle sacral artery sometimes deviates a little to the side.
It may proceed, not from the bifurcation of the aorta, but from one of the common
iliac arteries, usually from that of the left side. This artery represents the
caudal prolongation of the aorta of animals.

COMMON ILIAC ARTERIES.

The common iliac arteries, commencing at the bifurcation of the
aorta, pass downwards and outwards, diverging from each other, and
divide opposite the lumbo-sacral articulation into the internal and
external iliac arteries.

The common iliac arteries measure usually about two inches in
length. Both are covered by the peritoneum and the intestines, and
are crossed by the ureters near their point of division, as well as by the
branches of the sympathetic nerve which are directed towards the hypo-
gastric plexus. ‘They rest on the bodies of the vertebrxe, and come into
contact with the psoas muscle.

438 COMMON ILIAC ARTERY.

The common iliac artery of the right side is separated from the front
of the last lumbar vertebra, the two common iliac veins being inter-
posed. The artery of the left side is crossed by the branches of the
inferior mesenteric vessels.

Relation to Veins.—The left iliac vein, supported on the last lumbar
vertebra, lies to the inner side of, and below the left artery. On the
right side there are three veins in proximity to the artery; the right
iliac vein lying behind the lower part of the vessel, the left iliac vein

Fig. 281.—View or
THE RIGHT SIDE OF
A Mate Pegtnyis
SHOWING THE EX-
TERNAL AND IN-
TERNAL Inttac AR-
TERIES AND THEIR
BRANCHES. (A.T.) 2

The viscera of the
pelvis have been re-
moved as well as the
internaliliac veins: the
larger nerves have been
retained. a, body of
the fifth lumbar ver-
tebra ; 6, anterior and
superior spine of the
right ium; ec, left
auricular surface of
the sacrum ; c’, third
piece of the sacrum;
d, first piece of the
coccyx ; e, short sacro-
sciatic ligament; f,
tuberosity of the is-
chium covered inter-
nally by the great
sacro-sciatic ligament ;
g, obturator foramen ;
z, iliacus muscle; 1,
abdominal aorta; 1’,
middle sacral artery ;
2, 2, common iliac ar-
teries ; 2’, right exter-
nal iliac ; 3, vena cava
inferior; 4, 4, com-
mon iliac veins ; the
number on the right points by a line to the right internal iliac artery ; 4’, mght external
iliac vein ; 5, placed on the lumbo-sacral nervous trunk, points to the posterior division
of the internal iliac artery giving off the gluteal ; 5’, ilio-lumbar artery ; 5”, lateral sacral
artery with branches passing into the anterior sacral foramina ; 6, placed on the anterior
division of the first sacral nerve, points to the sciatic artery coming from the anterior
division of the internal iliac ; 7, pudic artery ; 7’, the same artery passing behind the
spine of the ischium, and proceeding within the ischium and obturator internus muscle,
accompanied by the pudic nerve towards the perineum; towards f, inferior hemorrhoidal
branches are given off ; 7”, superficial perineal artery and nerve ; 8, hypogastric artery,
with the obliterated remains of the umbilical artery cut short, and 8’, superior vesical
branches rising from it ; 9, obturator artery with the corresponding nerve and vein ; 9',
the pubic twigs which anastomose with descending twigs of the epigastric artery ; 10,
inferior vesical ; 11, middle hemorrhoidal vessels rising in this instance from the pudic ;
12, epigastric artery winding to the inside of +,+, the vas deferens and spermatic cord ;
13, circumflex iliac artery; 14, spermatic artery and vein divided superiorly ; 15, twigs
of the ilio-lumbar artery proceeding to anastomose with the circumflex iliac.

THE INTERNAL ILIAC ARTERY. 459

crossing behind it, and the vena cava, resulting from the union of the
two others, being on the right side of the artery at its upper end.

Varieties.— The place of division of these arteries is subject to great variety.
In two thirds of a large number of cases, it ranged between the middle of
the last lumbar vertebra and the upper margin of the sacrum; in one case
out of eight it was above, and in one case out of six it was below that space.
Most frequently the left artery was found to divide lower down than the right.
(R. Quain.)

The length varies in most instances between an inch and a half and three
inches, but it has been seen in some rare cases less than half an inch, and as
long as four inches and a half. In one instance recorded by Cruveilhier,
(‘ Anat. descript.” v. iii., p. 186,) the right common iliac artery was wanting,
and the internal and external vessels of that side arose as distinct branches from
the aorta.

Branches.—The common iliac artery often gives off a small unnamed branch
to the lymphatic glands, the ureter or the psoas muscle, and sometimes even a
larger branch—a renal artery, a lumbar, or the ilio-lumbar,

SURGICAL ANATOMY OF THE COMMON ILIAC ARTERY.

The common iliac artery may be reached in an operation by dividing the
abdominal muscles in the iliac region. The incision may be made, beginning
above the middle of Poupart’s ligament, and running parallel with that structure
towards the anterior superior spine of the ilium, thence curving for two inches
towards the umbilicus. In cutting through the muscles, care is to be taken of
the deep epigastric and circumflex iliac arteries, and especially of the peritoneum,
which, with the subperitoneal fascia and the adherent ureter, are to be carefully
stripped from the iliac and psoas muscles till the artery is reached. The
Celicate sheath is then scraped through and the ligature applied.

INTERNAL ILIAC ARTERY.

The internal iliac artery (art. hypogastrica,) extends from the bifur-
cation of the common iliac artery towards the sacro-sciatic foramen,
near which it divides into branches. It is usually about an inch and a
half in length, and is smaller than the external iliac in the adult, but
the reverse in the foetus. At its origin, the artery lies near the inner
border of the psoas muscle: lower down, it rests against part of the
pyriform muscle. Behind it are situated the internal iliac vein, and
the communicating branch which passes from the lumbar to the sacral
plexus of nerves : in front it is crossed by the ureter, which separates
it from the peritoneum.

BrancuEs.—The branches of the internal iliac artery, though con-
stant and regular in their general distribution, vary much in their
origin. They arise, in most instances, from two principal divisions of
the parent trunk, of which one is anterior to the other. From the
anterior division arise the superior vesical (connected with the pervious
portion of the foetal hypogastric artery), the inferior vesical, middle
hemorrhoidal, obturator, internal pudic, and sciatic arteries, and also,
in the female, the uterine and the vaginal arteries. The posterior

division gives off the gluteal, the ilio-lumbar, and the lateral sacral
arteries.

Varieties. —Zength—The internal iliac artery has been found as short as
half an inch, and sometimes as long as three inches, but it is not often less than

440 BRANCHES OF INTERNAL ILIAC ARTERY.

an inch in length. An instance has been observed in which this vessel was
absent, and its branches were derived from a bend of the external iliac artery
down into the pelvis (Preparation in Uniy. Coll, Mus., London). The lengths of
the common iliac and internal iliac arteries bear an inverse proportion to each
other—the internal iliac being long when the common iliac is short, and vice
versa. Moreover, when the common iliac is short, the internal iliac (arising
higher than usual) is placed for some distance above the brim of the pelvis, and
descends by the side of the external iliac to reach that cavity.

The place of division of the internal iliac into its branches varies between the
upper margin of the sacrum and the upper border of the sacro-sciatic foramen.

Branches.—Sometimes all the branches of the internal iliac artery arise without
the previous separation of that vessel into two portions.

In more than a fourth of R. Quain’s cases a branch, corresponding usually to
the ilio-lumbar artery, arose before the subdivision of the main trunk.

Hypogastric Artery.—Jn the fetus, the internal iliac artery, retaining almost
the full size of the common iliac, curves forwards from that artery to the side of
the urinary bladder, and ascends on the anterior wall of the abdomen to the
umbilicus. There the vessels of opposite sides come into contact with one
another, and with the umbilical vein, and coiling spirally round that vein in the
umbilical cord, they proceed to the placenta. To that part of the artery which
is placed within the abdomen, the term hypogastric is applied; the remaining
portion, passing onwards through the umbilicus to the placenta, being the proper
umbilical artery. After the cessation of the placental circulation at birth, the
two hypogastric arteries become impervious from the side of the bladder upwards
to the umbilicus, and are converted into fibrous cords. These two cords, being
shorter than the part of the peritoneum on which they rest, cause a fold of the
serous membrane to project inwards ; and thus are formed two fosse (external and
internal fossee of the peritoneum) on each side of the abdomen, in one or other of
which the projection of a direct inguinal hernia takes place. The part of the artery
intervening between its origin and the side of the bladder remains pervious,
although proportionally much reduced in size, and forms the trunk of the
superior vesical artery.

BRANCHES OF INTERNAL ILIAC ARTERY.

The superior vesical artery is, at its commencement, that part of
the hypogastric artery in the foetus which remains pervious after the
changes that take place subsequently to birth. It extends from the
anterior division of the internal iliac to the side of the bladder.

Branches.—(a) It distributes numerous branches to the upper part and sides
of the bladder.

(0) The artery of the vas deferens, arising from one of the lowest of these, is a
slender artery which reaches the vas deferens, and accompanies that duct in its
course through the spermatic cord to the back of the testicle, where it anasto-
moses with the spermatic artery.

(c) Other small branches ramify on the lower end of the ureter.

The inferior vesical artery (vesico-prostatic), derived usually from
the anterior division of the internal iliac, is directed downwards to the
lower part of the bladder, where it ends in branches which are distri-
buted to the base of the bladder, to the side of the prostate, and to the
vesiculee seminales. One offset, to be presently described, descends
upon the rectum.

The branches upon the prostate communicate more or less freely upon that
body with the corresponding vessels of the opposite side, and, according to Haller,
with the perineal arteries.

Small twigs of this vessel also run towards the subpubic arch, and in instances

VESICAL ARTERIES. 441

of deficient pudic arteries replace one or more of their branches, as will be more
fully noticed under those arteries.

Besides the superior and inferior vesical arteries, other smaller branches will
be found to reach the bladder, and usually one slender vessel which is distributed
particularly to the under surface of the vesiculz seminales,

Fig. 282.—Vinw or THe ViscerA oF THE Mate PELVIS FROM THR LEFT SIDE, SHOWING
THE VISCERAL AND Pupie ARTERIES (from R. Quain). 43

a, the os pubis divided a little to the left of the symphysis; }, placed close to the
upper part of the urinary bladder, upon which lies the vas deferens; c, placed on the
upper part of the rectum, near the left ureter ; c’, at the junction of the middle and lower
parts of the rectum points to the vesicula seminalis ; c”, the anus; d, the urethral bulb ;
e, the crus penis divided ; f, the short sacro-sciatic ligament attached to the spine of the
ischium ; 1, common iliac artery ; 2, internal iliac artery ; 3, gluteal artery cut short ;
4, common trunk of the sciatic and pudic arteries; 4’, sciatic artery cut as it 1s passing
out of the great sacro-sciatic foramen ; 5, placed on the divided surface of the ischium
near the spine, points to the pudic artery as it is about to re-enter the pelvis by the
lesser sacro-sciatic foramen ; 5’, the superficial perineal branches of the pudic ; 5”, the
pudie artery, proceeding to give the artery of the bulb, and passing on to give 6, the
artery of the crus penis and the dorsal artery of the penis ; 7, placed on the middle part
of the rectum, points to the descending branches of the superior hemorrhoidal artery ; 8,
the superior and middle vesical arteries; 9, the inferior vesical artery, of considerable
size in this instance, giving branches to the bladder, the vesicula seminalis, the rectum
(middle hemorrhoidal), and 9’, to the prostate gland.

Middle hemorrhoidal artery.—This branch is usually supplied to
the rectum by the inferior vesical artery, but sometimes proceeds from
other sources. It anastomoses with the branches of the other hamor-
rhoidal arteries.

The uterine artery is directed downwards from the anterior divi-
sion of the internal iliac artery towards the neck of the uterus.
Insinuating itself between the layers of the broad ligament, it passes
upwards on the side of the uterus, pursuing an exceedingly tortuous
course, and sends off numerous branches, which enter the substance of
that organ.

442 BRANCHES OF INTERNAL ILIAC ARTERY.

This artery supplies small branches to the bladder and the ureter; and, near
its termination, communicates with an offset directed inwards from the ovarian
artery.

Vaginal artery.—The vagina derives its arteries principally from a
branch which corresponds with the inferior vesical in the male. The
vaginal artery descends and ramifies upon the vagina, at the same time
sending some offsets to the lower part of the bladder over the neck, and
others to the contiguous part of the rectum.

Fig. 283.

Fig. 283.—View oF THE DISTRIBUTION OF THE ARTERIES TO THE ViSCERA OF THE
FremALE PELVIS, AS SEEN ON THE REMOVAL OF THE LEFT Os Innominarum, &c.
(from R. Quain). +
a, the left auricular surface of the sacrum ; 4, the spine of the ischium with the short

sacro-sciatic ligament ; c, the os pubis divided a little to the left of the symphysis ; d,

placed upon the sigmoid part of the colon, and d’ on the lower part of the urinary bladder,

point to the ureter ; e, on the upper part of the body of the uterus, points by a line to the
left ovary ; f, on the upper part of the bladder, points to the left Fallopian tube ; f’, round
ligament of the uterus; 1, left external iliac artery cut short ; 2, left internal iliac
artery ; 3, gluteal artery cut short ; 4, 4, left pudic artery from which a part has been
removed ; 4’, the same artery after it has re-entered the pelvis proceeding towards the
muscles of the perineum, clitoris, &c. ; 5, placed on the sacral nerves, points to the
sciatic artery ; 6, 6’, inferior vesical and vaginal arteries ; 6”, branches from these to the
rectum ; 7, uterine artery much coiled ; 8, the superior vesical, and 8’, the remains of
the hypogastric artery ; 9, 9, the left ovarian artery, descending from the aorta, and

emerging from below the peritoneum ; 10, the superior hemorrhoidal artery spreading
over the left side of the rectum.

The obturator artery, while it usually arises from the anterior divi-
sion of the internal iliac artery, is sometimes derived from its posterior
division. The artery is directed forwards along the inside of the pelvis
to reach the groove at the upper part of the thyroid foramen. By this
aperture it passes out of the pelvis, and immediately divides into its

THE OBTURATOR ARTERY, 443

terminal branches. In its course through the pelvis, the artery is
placed between the pelvic fascia and the peritoneum, a little below the
obturator nerve. Beneath the pubis it lies with its accompanying vein
and nerve in an oblique canal, formed partly by a groove in the bone,
and partly by fibrous tissue, after passing through which it divides
immediately into an external and an internal branch, which are deeply
placed behind the external obturator muscle.

Branches.—(a) Within the pelvis, besides others of smaller size, the obturator
artery often supplies a branch to the iliac fossa and muscle, and one which runs
backwards upon the urinary bladder.

(9) Anastomotic vessels, which may be called pudic, are given off by the obtu-
rator artery as it is about to escape from the pelvis: these vessels ramify on the
back of the pubis, and communicate behind the bone and the attachments of the
abdominal muscles, with small offsets from the epigastric artery. These anasto-
mosing branches lie to the inner side of the crural ring.

Fig. 284, A. and B.—Yrews
oF THE Lert WALL OF THE
PELVIS, WITH THE ATTACHED
ABDOMINAL MUSCLES FROM
THE INSIDE, SHOWING DIF-
FERENT POSITIONS OF THE
ABERRANT OBTURATOR AR-
TERIES (from R. Quain). +4
In A, a case is represented

in which the aberrant artery

passes to the outside of a

femoral hernia; in B. an in-

stance is shown in which it
surrounds the neck of the sac.

a, posterior surface of the

rectus muscle ; J, iliacus in-
ternus muscle ; c, symphysis
pubis ; d, obturator mem-
brane ; ¢, placed on the fascia
transversalis, points to the vas
deferens passing through the
internal inguinal aperture ; f,
‘the testicle ; +, the neck of a
femoral hernial sac; 1, the
external iliac artery ; 2, the ex-
ternal iliac vein ; below 2, the
obturator nerve; 3, the deep
epigastric artery ; 4, aberrant
obturator artery, arising from
the epigastric.

(c) The internal terminal
branch curves inwards be-
neath the obturator exter-
nus, close to the inner margin
of the thyroid foramen, and
furnishes branches to the
obturator muscles, the gracilis, and the adductor muscles.

(@) The external terminal branch has a similar arrangement near the outer
margin of the thyroid foramen ; it descends as far as the ischial tuberosity, and
supplies the obturator muscles, and the upper ends of the long muscles which
are attached to that tuberosity. This branch usually sends off a small artery,
which enters the hip-joint through the cotyloid notch, and ramifies in the
pai fatty tissue, and along the round ligament as far as the head of the

emur,

444 BRANCHES OF INTERNAL ILIAC ARTERY.

The two terminal branches of the obturator artery communicate with each
other near the lower margin of the obturator ligament, and anastomose with
branches of the internal circumflex artery. The external branch also communi-
cates with offsets from the sciatic artery near the tuber ischii.

Varieties.—The obturator artery frequently has its origin transferred to the
commencement of the epigastric artery, and sometimes to the external iliac at
its termination.

In 361 cases observed by R. Quain, the origin of the obturator artery varied
as follows. In the proportion of 2 cases out of 3, it arose from the internal iliac:
in 1 case out of 34, from the epigastric: in a very small number of cases (about
1 in 72), it arose by two roots from both the above-named vessels ; and in about
the same proportion, from the external iliac artery.

Sometimes the obturator artery arises from the epigastric on both sides of the
same body, but in the majority of instances, this mode of origin of the vessel is
met with only on one side.

When the obturator artery arises from the epigastric, it turns backwards into
the pelvis to reach the canal at the upper part of the thyroid foramen; and in
this course it is necessarily close to the crural ring, the opening situated at
the inner side of the external iliac vein, through which hernial protrusions
descend from the abdomen into the thigh. In the greater number of instances
the artery springs from near the root of the epigastric, and is directed backwards
close to the iliac vein, and therefore lies to the outer side of the femoral ring ;
but in other instances, arising from the epigastric artery higher up, it occasionally
crosses over the ring, and curves to its inner side. It is when it takes this last
course that the obturator artery is liable to be wounded in the operation for
dividing the stricture in a femoral hernia.

The anastomosis which normally exists between the obturator artery and the
epigastric explains the nature of the change which takes place when the origin
of the obturator artery is transferred from the one place to the other. In such
cases one of the anastomosing vessels may be supposed to have become enlarged,
and the posterior or proper root of the obturator artery to have remained unde-
veloped or to have been obliterated in a proportionate degree.

The internal pudic artery is a branch of considerable size (smaller
in the female than in the male), which is distributed to the external
generative organs. The following description of this artery has refer-
ence to its arrangement in the male; its distribution in the female will
be noticed separately.

The pudic artery arises from the anterior division of the internal
iliac, sometimes by a trunk common to it and the sciatic artery. Pro-
ceeding downwards, it emerges from the pelvis along with the sciatic
artery, through the great sacro-sciatic foramen, and continuing in a
uniformly curved course, it re-enters the pelvis by the small sacro-
sciatic foramen, immediately below the ischial spine, and passes forward
on the inner side of the tuber ischii, in the substance of the obturator
fascia.

Distant at first from the lower margin of the ischial tuberosity an
inch or an inch and a half, it approaches the surface at the inner
margin of the pubic arch, and lies subjacent to the triangular ligament
or superficial layer of the subpubic fascia. Finally, piercing this fascia,
it divides below the subpubic arch into the dorsal artery of the penis
and the artery of the corpus cavernosum.

In the first part of its course, whilst within the pelvis, the pudic
artery lies to the outer side of the rectum, and in front of the pyri-
formis muscle and the sacral nerves. Thence onwards it is accompanied
by the pudic nerve and vein. On the ischial spine it is covered by the
gluteus maximus muscle close to its origin. In the obturator fascia it

THE INTERNAL PUDIC ARTERY. 445

lies externally to the ischio-rectal fossa and internally to the obturator
internus muscle, and beneath the triangular ligament it is crossed by
the deep transverse perineal muscle.

Branches.—(a) The inferior or external hemorrhoidal arteries, two or three
in number, incline inwards from the pudic artery as it passes outside the ischio-
rectal fossa above the tuber ischii. These small vessels run across the ischio-
rectal fossa, through the fat in that space, and are distributed to the sphincter
and leyator ani muscles, and to the parts surrounding the anus.

(b) The superficial perineal artery, a long, slender, but regular vessel, supplies

Fig. 285.—Vinw oF THE DistRiBuTION OF THE ARTERIES TO THE VISCERA OF THE MALT
PELVIS, AS SEEN ON THE REMOVAL OF THE Lert Os Innominatum, &c. (from R, Quain). 4
a, left external oblique muscle of the abdomen divided ; 0, internal oblique ; c, trans-
versalis ; d, d, the parts of the divided rectus muscle ; e, psoas magnus muscle divided ;
f, placed on the left auricular surface of the sacrum, points by a line to the sacral
plexus of nerves ; y, placed on the os pubis, sawn through a little to the left of the
symphysis, points to the divided spermatic cord ; h, the cut root of the crus penis ; 7, the
bulb of the urethra ; &, external sphincter ani muscle ; /, spine of the ischium, to
which is attached the short sacro-sciatic ligament ; m, the parietal peritoneum ; 7, the
upper part of the urinary bladder ; n’, n’, the left vas deferens descending towards the
vesicula seminalis ; n", the ureter ; 0, the intestines; 1, the common iliac at the place
of its division into external and internal iliac arteries ; 2, left external iliac artery ; 3,
internal iliac ; 4, obliterated hypogastric artery, over which the vas deferens is seen
passing, with the superior vesical artery below it ; 5, middle vesical artery ; 6, inferior
vesical artery, giving branches to the bladder, and descending on the prostate gland and
to the back of the pubis; 7, placed on the sacral plexus, points to the common trunk of
the pudic and sciatic arteries ; close above 7, the gluteal artery is seen cut short ; 8,
sciatic artery cut short as it is escaping from the pelvis ; 9, placed on the rectum, points
to the pudic artery as it is about to pass behind the spine of the ischium ; 9’, on the
lower part of the rectum, points to the inferior hemorrhoidal branches; 9", on the
perineum, indicates the superficial perineal branches ; 9’, placed on the prostate gland,
marks the pudic artery as it gives off the arteries of the bulb and of the crus penis ; 10,
placed on the middle part of the rectum, indicates the superior hemorrhoidal arteries as
they descend upon that viscus.

446 BRANCHES OF INTERNAL ILIAC ARTERY.

the scrotum and the upper part of the perineum. Given off from the pudic
artery in front of the hemorrhoidal branches, it turns upwards parallel with the
pubic arch, crosses the transverse muscle of the perineum, and runs forwards
under cover of the superficial fascia, between the erector penis and accelerator
urine muscles, supplying both. In this course the artery gradually becomes
superficial, and is finally distributed to the skin of the scrotum and the dartos.
It not unfrequently gives off the following branch.

Fig. 286.—DIssEcTION OF
THE PERINEUM IN A
Youna Mae Sussecr
SHOWING THE Buroop-
Vussets, &c. (A.T.) $

This drawing is made
from a preparation upon
a modification of the plan
of R. Quain’s 61st and
62nd Plates. The right
side shows a superficial,
the left a deeper view.

a, the anus, with a
part of the integument
surrounding it; 6, left
half of the bulb of the
urethra exposed by the
removal of a part of the
bulbo-cavernosus muscle ;
¢, coecyx ; d, right tube-
rosity of the ischium ; e,
€, Superficial perineal fas-
cia passing forward upon
the scrotum; f, right
ischio-rectal fossa, from
which the fat and fascia
have not been removed ;
g, gluteus maximus mus-
cle; 1, placed on the
right transversus perinei
muscle, points to the su-
perficial perineal artery
as it emerges in front (in
this case) of the muscle ;
1’, placed on the left side
on the surface of the tri-
angular ligament near its
reflection into the super-
ficial fascia, points to the
superficial perineal artery
cut short ; 2, on the right
: ischio-cavernosus muscle,
points to the superficial perineal arteries and nerves passing forward ; 2’, the same on the
jeft side, the vessels and nerves having been divided there ; 3, on the triangular ligament
of the right side points to the transverse perineal branch of the superficial perineal
artery ; 4, on the left tuberosity of the ischium, points to the pudic artery deep in the
ischio-rectal fossa ; 5, 5', the inferior hemorrhoidal branches of the pudic arteries and
nerves ; 6, on the left side, placed in a recess from which the triangular ligament or
anterior layer of the subpubic fascia has been removed to show the continuation of the
pudic artery, its branch to the bulb, and one of Cowper’s glands.

(c) The transverse perineal artery, a very small vessel, is frequently a branch
of the preceding, but in some instances arises from the pudic artery. It crosses
the perineum, and terminates in small branches which are distributed to the

VARIETIES OF THE PUDIC ARTERY, 447

transverse muscle, and to the parts between the anus and the bulb of the
urethra.

(d) The artery of the bulb is, surgically considered, an important vessel. It
is very short; arising from the pudic between the layers of the sub-pubic fascia,
and passing transversely inwards, this artery reaches the bulb a little in front of
the central point of the perinzeum, and ramifies in the erectile tissue. It gives a
branch to Cowper's gland.

(e) The artery of the corpus cavernosum (profunda penis), one of the terminal
branches of the internal pudic, runs a short distance between the crus penis and
the ramus of the pubis, and then continuing forward penetrates the crus, and
ramifies in the corpus cavernosum.

(f) The dorsal artery of the penis runs between the crus and the pubic sym-
physis : having pierced the suspensory ligament, it continues along the dorsum
of the penis immediately beneath the skin, and parallel with the dorsal vein, as
well as with the corresponding artery of the opposite side. It supplies the integ-
ument of the penis, and the fibrous sheath of the corpus cavernosum, anasto-
mosing with the deep arteries ; and, near the corona glandis, divides into branches,
which supply the glans and the prepuce. .

Varieties.— Origin. The pudic artery is sometimes small, or it is defective in
one or two, or even three of its usual branches, which, in those circumstances,
are supplied by a supplemental vessel, the accessory pudic. The defect most
frequently met with is that in which the pudic ends as the artery of the bulb,
whilst the arteries of the corpus cavernosum and the dorsum of the penis are
derived from the accessory pudic. But all the three arteries of the penis may be
supplied by the accessory pudic, the pudicitself ending as the superficial perineal.
A single accessory pudic has been found to supply both cavernous arteries, whilst the
pudic of the right side gave both dorsal arteries. On the other hand, cases have
occurred in which only a single branch was furnished by the accessory artery,
either to take the place of an ordinary branch altogether wanting, or to supplement
one of the branches which was diminutive in size,

The accessory pudic generally arises from the pudic itself, before the passage of
that vessel from the sacro-sciatic foramen, and descends within the pelvis, and
along the lower part of the urinary bladder. It lies on the upper part of the
prostate gland, or it may be, for a short space, likewise on the posterior margin,
and then proceeding forwards above the membranous part of the urethra, reaches
the perinzeum, by piercing the fascia of the sub-pubic arch.

The accessory pudic sometimes arises from other branches of the internal iliac
artery, and is not unfrequently connected with the prostatic or some other branch of
the inferior vesical artery. A vessel having a similar distribution may spring from
the external iliac, through an irregular obturator, or through the epigastric artery.

Branches.—The artery of the bulb is sometimes small, sometimes wanting on
one side, and occasionally it isdouble. But amore important deviation from the
common condition is one sometimes met with, in which the vessel. arising earlier,
and crossing the perineum farther back than usual, reaches the bulb from
behind. In such a case there is considerable risk of dividing the artery in per-
» forming the lateral operation for stone. On the other hand, when this small
vessel arises from an accessory pudic artery, it lies more forward than usual, and
out of danger in case of operation.

The dorsal artery of the penis has been observed to arise from the deep femoral
artery and to pass obliquely upwards and inwards to reach the root of the penis,
Tiedemann gives a drawing of this variety.

The pudic artery in the female.—In the female this vessel is much
smaller than in the male. Its course is similar, and it gives the fol-
lowing branches.

The superficial perineal branch is distributed to the labia pudendi.
The artery of the bulb supplies the mass of erectile tissue above and at
the sides of the entrance of the vagina, named the bulb of the vagina ;
whust the two terminal branches, corresponding to the artery of the

448 BRANCHES OF INTERNAL ILIAC ARTERY.

corpus cavernosum and the dorsal artery of the penis, are distributed to
the clitoris, and are named the profunda and dorsal arteries.

The sciatic artery, the largest branch of the internal iliac trunk,
excepting the gluteal, is distributed to the muscles on the back of the
pelvis. It descends upon the pelvic surface of the pyriformis muscle
and the sacral plexus of nerves ; and turning backwards beneath the
border of that muscle, it passes between it and the superior gemellus,
and thus escapes from the pelvis, along with the great sciatic nerve and
the pudic artery, at the lower part of the great sciatic foramen. Outside
the pelvis, this artery lies in the interval between the tuber ischii and
the great trochanter, covered by the gluteus maximus.

Branches.—The sciatic artery gives off several branches to the external rotator
muscles of the thigh, on which it lies, and to the great gluteus by which it is
concealed. Two others have received special names, viz., the following :—

(a) The coccygeal, inclines inwards, and piercing the great sacro-sciatic liga-
ment, reaches the posterior surface of the coccyx, and ramifies in the fat and
skin about that bone.

(>) The comes nervi ischiadici runs downwards, accompanying the sciatic nerve,
along which it sends a slender vessel.

Some of the branches of this artery are distributed to the capsule of the hip-
joint; whilst others, after supplying the contiguous muscles, anastomose with the
gluteal, the internal circumflex, and the superior perforating arteries in the upper
part of the long flexor muscles of the thigh.

The gluteal artery, the largest branch of the internal iliac, is dis-
tributed to the muscles on the outside of the pelvis. It inclines down-
wards to the great sacro-sciatic foramen, and escaping from the cavity
of the pelvis, between the contiguous borders of the middle gluteal and
the pyriform muscles, divides immediately into a superficial and a deep
branch.

Branches. —(a) The superficial branch running between the gluteus maximus
and gluteus medius, divides into ramifications which are most copiously distri-
buted to the gluteus maximus, and anastomose with the sciatic and posterior
sacral arteries.

(6) The deep branch, situated between the gluteus medius and gluteus minimus,
runs in an arched direction forwards, and divides into two other branches. One
of these, the superior branch, follows the upper border of the gluteus minimus
beneath the middle gluteal muscle and the tensor of the fascia lata, towards the
anterior iliac spine, and, after having freely supplied the muscles between which
it passes, anastomoses with the circumflex iliac and the ascending branches of the
external circumflex arteries. The second or inferior branch descends towards the
great trochanter, supplies the gluteal muscles, and anastomoses with the external
circumflex and the sciatic arteries.

(c) A nutrient branch enters the ilium at the place where the artery emerges
from the pelvis.

The ilio-lumbar artery resembles in a great measure one of the
lumbar arteries. It passes outwards beneath the psoas muscle and the
external iliac vessels, to reach the margin of the iliac fossa, where it
separates into a dwmbar and an iliac division. The first of these ramifies
in the psoas and quadratus muscles, communicating with the last
lumbar artery, and furnishing branches to the vertebral canal. The
second or diac division, turning downwards and outwards, either in
the iliacus muscle or between it and the bone, anastomoses with the
circumflex iliac artery, and even with the external branches of the
epigastric.

.

ILIO-LUMBAR AND LATERAL SACRAL ARTERIES. 449

Varieties.—The ilio-lumbar artery sometimes arises from the internal iliac
above the division of that trunk; and more rarely from the common iliac. The
iliac and lumbar portions sometimes arise separately from the parent trunk.

Fig. 287.—ARTHERIES oF THE Back ~ Fig, 287.
oF THE PrELyis AND UPPER GOP
Part or THE ‘Hien (from
Tiedemann). +

—

a, crest of the ilium ; 0, tuber-
osity of the ischium and lower
attachment of the great sacro-
sciatic ligament; c, great tro-
chanter ; d, integument round the
anus; ¢é, great sciatic nerve; 1,
trunk of the gluteal artery as it
issues from the great sacro-sciatic
foramen, the superficial branches
cut short, the deep arch seen pass-
ing round on the upper part of
the gluteus minimus muscle; 2,
placed on the great sacro-sciatic
ligament, points to the pudic artery
at the place where it winds over
the back of the spine of the ischium ;
2’, the continuation of the artery
towards the perineum on the in-
side of the tuberosity and ramus
of the ischium; 3, 3, the sciatic
artery, the upper figure placed on
the pyriformis muscle, the lower
on the great sciatic nerve; 4, 4’,
first perforating branch of the
femoral anastomosing with the pos-
terior branch of the internal circum-
flex artery, which appears between
the quadratus and the abductor mus-
cles ; 5 and 6, part of the second Mh
and third perforating arteries.

When the lowest of the lumbar arteries is wanting it is replaced by a branch
from the ilio-lumbar, which is increased in size, and by a small offset from the
middle sacral artery.

‘

The lateral sacral arteries are usually two in number on each side,
though occasionally they are united into one. The two arteries arise
close together from the posterior division of the internal iliac. One is
distributed upon the upper, and the other upon the lower part of the
sacrum.

Both arteries pass downwards, at the same time inclining somewhat
inwards, in front of the pyriform muscle and the sacral nerves, which
they supply with twigs, and reach the inner side of the anterior sacral
foramina. Continuing to descend, the lower one approaches the middle
line, and anastomoses with the middle sacral artery.

Branches.—The lateral sacral arteries give off a series of branches which enter
the anterior sacral foramina. Each of these, after having furnished within the
foramen a spinal branch, which ramifies on the bones and membranes in the
interior of the sacral canal, escapes by the corresponding posterior sacral foramen,

and is distributed upon the dorsal surface of the sacrum to the skin and
muscles,

VOL. I. @G

450 THE EXTERNAL ILIAC ARTERY.

EXTERNAL ILIAC ARTERY.

The external of the two arteries resulting from the division of the
common iliac forms a large continuous trunk, which extends down-
wards in the limb as far as the lower border of the popliteus muscle,
but, for convenience of description, it is named in successive parts of
its course external iliac, femoral and popliteal.

The external iliac artery, larger than the internal iliac, is placed
within the abdomen, and extends from the division of the common iliac
to the lower border of Poupart’s ligament, where the vessel enters the
thigh, and is named femoral. Descending obliquely outwards, its
course through the abdominal cavity may be marked by a line drawn
from the left side of the umbilicus to a point midway between the
anterior superior spinous process of the ilium and the symphysis pubis.
This line would also indicate the direction of the common iliac artery,
of which the external iliac is the direct continuation.

Fig. 288.—ViEw oF
THE PRINCIPAL AR-
TERIES OF A MALE
Petyis. (A.T.) 4

For the detailed de-
scription of this figure
see p. 438.

2’, the right external
iliac artery, accompa-
nied by the correspond-
ing vein 4’, passing
below into the femoral
vessel under Poupart’s
ligament ; 12, epigas-
tric artery winding to
the inside of +, +,
the spermatic cord ;
the epigastric artery is
cut short superiorly ;
13, circumflex iliac
artery anastomosing
with 15, branches of
the ilio-lumbar; 14,
spermatic artery and
vein descending to join
the spermatic cord ;
+, within the pelvis,
the vas deferens de-
scending from the cord
towards the bladder.

ion

The vessel is
covered by the
peritoneum and
intestines. It lies along the upper margin of the true pelvis, resting
upon the inner border of the psoas muscle. The artery, however, is
separated from the muscle by the fascia iliaca, to which it is bound,
together with the external iliac vein, by the sub-peritoneal tissue.

Relation to Veins, &c.—The external iliac vein lies at first behind the
artery with an inclination to the inner side; but, as both vessels ap-
proach Poupart’s ligament at the fore part of the pelvis, the vein is on
the same plane with the artery and quite to the inner side, being borne

THE EXTERNAL ILIAC ARTERY. 451

forwards by the bone. At a short distance from its lower end the
artery is crossed by the circumflex iliac vein.

Fig. 289.—Virew oF tHE DiIstTRIBUTION
AND ANASTOMOSIS OF THE DerEp EptI-
GASTRIC AND INTERNAL Mammary AR-
TERIES (from Tiedemann). +

For the detailed description of this
figure, see p. 390.

7, placed on the transversalis muscle
above the internal inguinal aperture, points
to the last part of the external iliac artery
at the place where it gives origin to 8, the
epigastric and 9, the circumflex iliac ar-
tery ; 10, anastomosis of the epigastric
artery and the abdominal branch of the in-
ternal mammary in and behind the rectus
muscle ; 11, the spermatic cord receiving
the cremasteric branch from the epigastric
artery; 12, femoral artery; 13, femoral
vein ; 14, a lymphatic gland closing the
femoral ring.

Large lymphatic glands are found
resting upon the front and inner
side of the vessel ; and the sper-
matic vessels descend upon it
near its termination. A branch
of the genito-crural nerve crosses
it just above Poupart’s ligament.

BrancuEs.—The external iliac
artery supplies some small branches
to the psoas muscle and the neigh-
bouring lymphatic glands, and,
close to its termination, two other
branches of considerable size,
named the epigastric and the
circumflex iliac, which are dis-
tributed to the walls of the
abdomen.

1. The deep epigastric ar-
tery (inferior epigastric) arises
from the fore part of the external
iliac artery, usually a few lines
above Poupart’s ligament. It
first inclines downwards, so as to
get on a level with the ligament,
and then passes obliquely upwards
and inwards between the fascia
transversalis and the peritoneum,
to reach the rectus muscle of the —=
abdomen. It ascends almost vertically behind the rectus, and rising
within the sheath is placed between it and the muscle, and terminates
at some distance above the umbilicus in offsets which ramify in the
substance of the muscle and anastomose with the terminal branches of
the internal mammary and inferior intercostal arteries.

Ga2

459 BRANCHES OF EXTERNAL ILIAC ARTERY.

The epigastric artery is accompanied by two veims, which unite into
a single trunk before ending in the external iliac vein.

In its course upwards from Poupart’s ligament to the rectus muscle,
the artery passes close to the inner side of the internal abdominal ring ;
and the vas deferens, entering through the ring, turns behind the artery
in descending into the pelvis.

Branches. —These are small but numerous.

(a) The cremasteric artery, a slender branch, accompanies the spermatic cord,
and, supplying the cremaster muscle and other coverings of the cord, anasto-
moses with the spermatic artery.

(b) Several muscular branches arise from each side of the epigastric artery,
ramify in the rectus muscle, and communicate with the branches of the lumbar
and circumflex iliac arteries.

(c) Superficial branches perforate the abdominal muscles, and join beneath
the skin with branches of the superficial epigastric artery.

(d) The pubic is a small branch, which ramifies behind the pubes, and commu-
nicates by means of one or more descending twigs with a similar branch from
the obturator artery

Fig, 290, Fig. 290.—Vinw oF THE RELATION oF
THE VESSELS OF THE GROIN TO A
Fremoran Hurnta, &ec. (from R.
Quain). +

In the upper part of the figure a
portion of the fiat muscles of the
abdomen has been removed, displaying
in part the transversalis fascia and
peritoneum ; in the lower the fascia
lata of the thigh is in part removed
and the sheath of the femoral vessels
opened.

a, anterior superior spinous process
of the ilium ; 6, aponeurosis of the ex-
ternal oblique muscle; c, the perito-
neum and fascia transversalis ; d, the
iliac portion of the fascia lata near the
saphenic opening ; ¢, sac of a femoral
hernia opened ; 1, femoral artery ; 2,
femoral vein at the place where it is
joined by the saphena vein ; 3, deep
epigastric artery and vein; +, placed
upon the upper part of the femoral
vein close below the common trunk of
the epigastric and an aberrant obtu-
rator artery ; the latter artery is seen
in this case to pass close to the vein
between it and the neck of the hernial
tumour.

2. The deep circumflex iliac artery, smaller than the preceding
vessel, arises from the outer side of the iliac artery near Poupart’s liga-
ment, and is directed outwards behind that. band to the anterior supe-
rior iliac spine. Following thence the crest of the hip-bone, the artery
vives branches to the iliacus and abdominal muscles, and anastomoses
with the ilio-lumbar artery. In its course outwards, this artery lies
in front of the transversalis fascia, at the junction of this with the
fascia iliaca.

Two veins accompany the circumflex iliac artery ; these unite below

SURGICAL ANATOMY OF THE ILIAC ARTERIES. 453

into a single vessel, which crosses the external iliac artery about an
inch above Poupart’s ligament, and enters the external iliac vein.

Branch.—The muscular branch is given off near the iliac crest, and ascends on
the fore-part of the abdomen between the transversalis and internal oblique
muscles: having supplied those muscles, it anastomoses with the lumbar and
epigastric arteries. This branch varies much in size, and is occasionally replaced
by several smaller muscular offsets.

Varieties.—Size.—The external iliac artery is much diminished in those rare
cases in which the principal blood-vessel of the lower limb is continued from the
sciatic branch of the internal iliac, and ends in the muscles of the front of the
thigh, taking the place of the profunda.

Branches.—The usual number of two principal branches of the external iliac
artery may be increased by the separation of the circumflex iliac into two branches,
or by the addition of a branch usually derived from another source, such as the
internal circumflex artery of the thigh or the obturator artery.

The decp epigastric artery occasionally arises higher than usual, as at an inch
and a half, or even two inches and a half, above Poupart’s ligament ; and it has
been seen to arise below that ligament from the femoral, or from the deep
femoral artery. The epigastric frequently furnishes the obturator artery as
already described ; and two examples are recorded in which the epigastric artery
arose from an obturator furnished by the internal iliac artery. (Monro, “ Morbid
Anatomy of the Human Gullet,’ &c., p. 427. A. K. Hesselbach, “ Die sicherste
Art des Bruchschnittes,’ &c.) In a single instance the epigastric artery was
represented by two branches, one arising from the external iliac, and the other
from the internal iliac artery. (Lauth, in “ Velpeau’s Médecine Opératoire,” v. ii.,
p. 452.) Some combinations of the epigastric with the internal circumflex, or
with the circumflex iliac, or with both those vessels, have been noticed.

The deep circumflex iliac artery sometimes deviates from its ordinary position,
—arising ata distance not exceeding an inch above Poupart’s ligament. Devia-
tions in the opposite direction are more rarely met with; it has in a few cases
been observed to arise below the ligament, from the femoral artery.

SURGICAL ANATOMY OF THE ILIAC ARTERIES.

The external iliac artery is usually tied about midway between the origins of
the internal iliac and of the deep epigastric arteries. It is reached by a curved
incision about three and a half inches long, made through the abdominal muscles
an inch above and parallel to Poupart’s ligament. After dividing the transver-
salis fascia, the peritoneum (to which the spermatic vessels adhere) is raised,
and the artery is found at the margin of the pelvis, running along the inner
border of the psoas muscle. The vein is close to the artery, but on its inner
and posterior aspect. In order to pass the ligature, it is necessary to divide the
thin subserous membrane which binds the vessel down to the fascia iliaca.

The internal iliac artery is reached by a similar but somewhat longer incision.
The steps of the operation are the same, but owing to the shortness of the vessel,
and the greater depth at which it is placed, the operation itself is more difficult.

FEMORAL ARTERY.

The femoral artery is that portion of the artery of the lower limb
which lies in the upper two-thirds of the thigh,—its limits being
marked above by Poupart’s ligament, and below by the opening in the
great adductor muscle, after passing through which, the artery receives
the name of popliteal.

A general indication of the direction of the femoral artery over the
fore-part and inner side of the thigh is given by a line reaching from a
point midway between the anterior superior iliac spine and the sym-
physis of the pubes above to the inner side of the internal condyle of
the femur below. At the upper part of the thigh, it lies along the
middle of a depression between the muscles covering the femur on the

454 THE FEMORAL ARTERY.

Fig. 291.—Anrertor View oF THE Ar-
TERIES oF THE PrELvis, THIGH, AND

Knee (from Tiedemann). 4

a, anterior superior iliac spine ; 6, tensor
vagine femoris muscle ; c, vastus internus ;
d, tendon of the adductor magnus ; e, sar-
torius ; f, rectus muscle ; g, the colon lying
upon the left iliac artery ; A, urinary blad-
der; 1, division of the abdominal aorta
into the common iliac arteries; 1’ middle
sacral artery ; 2, left common iliac artery ;
3, external iliac; 3’, deep circumflex iliac
branch ; 3”, epigastric winding to the
inside of the spermatic cord, and giving off
3, its cremasteric branch; 4, femoral
artery, on the right side shown in Scarpa’s
triangle, on the left exposed as far as
Hunter’s canal; 4! superficial circumflex
iliac and epigastric of the right side ; 4",
superficial pudic and inguinal branches ; 5,
profunda femoris artery, descending on the
left side behind the adductor longus; 6,
external circumflex ; 6’, its ascending or
gluteal branches; 6", its descending branches;
7, 7’, internal circumflex artery ; 8, superior
perforating ; 8’, second perforating branch ;
9,9, muscular branches of the femoral ar-
tery ; 9’, anastomotic branch ; 10, internal eu
superior articular branch of the popliteal ; 10’, inferior branch.

outer side, and the adductor muscles on the inner side of the limb, and
which is known by the name of Scarpa’s triangle. In this situation

RELATIONS OF THE FEMORAL ARTERY, 455

the beating of the artery may be felt, and the circulation through the
vessel may be most easily controlled by pressure. Below the upper
third of the thigh it is crossed by the sartorius muscle, the upper and
inner border of which forms the outer wall of the triangle, and which
conceals the vessel in the remainder of its course. In the first part of
its course the femoral artery is covered only by the skin and fascia
lata, and by the crural sheath which invests both the artery and vein.
In the lower part of its course it is deeply placed, being covered not
only by the sartorius muscle, but by a dense stratum of fibrous struc-
ture, which stretches across from the tendons of the long and great
adductors to the vastus internus muscle, and encloses the space called
Hunter’s canal, in which the vessels lie.

The artery rests successively upon the following parts. First, upon
the psoas muscle, by which it is separated from the margin of the pelvis
and the capsule of the hip-joint ; next it is placed in front of the pec-
tineus muscle, the deep femoral artery and vein being interposed ;
afterwards, it lies upon the long adductor muscle ; and lastly, upon the
tendon of the great adductor, the femoral vein being placed between
the tendon and the artery. At the lower part of its course, it has
immediately on its outer side the vastus internus muscle, which inter-
venes between it and the inner side of the femur.

Fig. 292.—Vinw or THE Fremoran VEs- Fig. 292.
SELS, WITH THEIR SMALLER SUPERFICIAL
BRANCHES IN THE Ricur Groin (from R,

Quain).

a, the integument of the abdomen ; 8, the
superficial abdominal fascia; 6’, the part
descending on the spermatic cord ; ¢, c, the
aponeurosis of the external oblique muscle ;
c’, the same near the external abdominal
ring ; ec”, the inner pillar of the ring ; d, the
iliac part of the fascia lata ; d’, the pubic
part ; ¢, e, the sheath of the femoral vessels
laid open, the upper letter is immediately
over the crural aperture ; e’, sartorius muscle
partially exposed ; 1, femoral artery, having
2, the femoral vein to its inner side, and the
septum of the sheath shown between the two
vessels ; 3, the principal saphenous vein ;
3, its anterior branches; 4, the superficial
circumflex iliac vein and arterial branches to
the glands of the groin ; 5, the superficial
epigastric vein ; 6, the external pudic arteries
and veins; 7 to 8, some of the lower inguinal
glands receiving twigs from the vessels ; 9,
internal, 10, middle, and 11, external cuta-
neous nerves.

At the groin the artery, after hay- /
ing passed over the margin of the
pelvis, is placed slightly in front of or internal to the head of the femur ;
and at its lower end, the vessel lies close to the inner side of the shaft
of the bone ; but in the intervening space, in consequence of the pro-
jection of the neck and shaft of the femur outwards, while the artery

holds a straight course, it is separated from the bone by a considerable
interval.

456 BRANCHES OF THE FEMORAL ARTERY,

Relation to Veins.—The femoral vein is very close to the artery, both
being enclosed in the same sheath, and separated from each other only
by a thin partition of fibrous membrane. At the groin the vein lies in
the same plane as the artery, and on the inner side ; but gradually
inclining backwards, it is placed behind it at the lower end of Scarpa’s
space, and afterwards gets somewhat tothe outer side. The deep
femoral vein, near its termination, crosses behind the femoral artery ;
and the long saphenous vein, as it ascends on the fore part of the
limb, lies to the inner side; but it not unfrequently happens that a
superficial vein of considerable size ascends for some space directly over
the artery.

Relation to Nerves.—At the groin the anterior crural nerve lies a little
to the outer side of the femoral artery (about a quarter of an inch),
separated from the vessel by some fibres of the psoas muscle and by
the sheath and fascia. Lower down in the thigh, the long saphenous
nerve accompanies the artery until this vessel perforates the adductor
magnus. There are likewise small cutaneous nerves which cross the
artery.

BraNncHES.—The femoral artery gives off the following branches :—
some small and superficial, which are distributed to the integument
and glands of the groin and ramify on the lower part of the abdomen,
viz., the external pudic (superior and inferior), the superficial epigastric,
and the superficial circumflex iliac; the great nutrient artery of the
muscles of the thigh, named the deep femoral; several muscular
branches ; and lastly, the anastomotic artery, which descends on the
inner side of the knee-joint.

The portion of the femoral artery extending from its commencement to the
origin of the deep femoral, a part varying from an inch to two inches in length,
is sometimes distinguished by surgical writers as the common femoral, and
described as dividing into the superficial and deep femoral arteries.

The external pudic arteries arise either separately or by a common
trunk from the inner side of the femoral artery. The superior, the
more superficial branch, courses upwards and inwards to the pubic
spine, crosses the external abdominal ring, passing in the male over the
spermatic cord, and is distributed to the integuments on the lower part
of the abdomen, and on the external organs of generation. The iferior
branch. more deeply seated, extends inwards, resting on the pectineus
muscle, and covered by the fascia lata, which it pierces on reaching
the inner border of the thigh, and is distributed to the scrotum in
the male, or to the labium in the female, its branches inosculating
with those of the superficial perineal artery.

The superficial epigastric artery, arising from the femoral vessel,
about half an inch below Poupart’s ligament, passes forwards through the
fascia lata, and runs upwards on the abdomen in the superficial fascia
covering the external oblique muscle. Its branches, ascending nearly
as high as the umbilicus, anastomose with superficial branches of the
epigastric and internal mammary arteries.

The superficial circumflex iliac artery runs outwards in the direc-
tion of Poupart’s ligament towards the iliac spine, across the psoas and
iliacus muscles: to both of these it gives small branches, as also

THE DEEP FEMORAL ARTERY. 457

some others which pierce the fascia lata; it is distributed to the
integument.

All the preceding arteries give small branches to the lymphatic
glands in the groin.

Fig. 293.—Dsrp Vinw oF THE Frmo-
RAL ARTERY AND ITS BRANCHES ON
THE Lert Srpk (from R. Quain). 3

The sartorius muscle has been re-
moved in part, so as to expose the
artery in the middle third of the thigh.
a, the anterior superior iliac spine ; 0),
the aponeurosis of the external oblique
muscle near the outer abdominal ring,
c, rectus femoris muscle; d, abductor
longus ; ¢, fibrous sheath of Hunter's
canal covering the artery ; 1, femoral
artery ; 1’, femoral vein divided and
tied close below Poupart’s ligament ; 2,
profunda femoris artery ; 3, anterior
crural nerves, the figure lies between
two superficial epigastric branches ; 3’,
superficial circumflex iliac artery; 4,
internal circumflex branch ; 5, super-
ficial pudic branches ; 6, external cir-
cumflex branch, with its ascending
transverse and descending branches
separating from it; 6’, twigs to the
rectus muscle; 7, branches to the
vastus internus muscle; 8 and 9,
some of the muscular branches of the
femoral ; +, origin of the superior per-
forating artery.

The deep femoral artery
—(profunda femoris) the prin-
cipal nutrient vessel of the
thigh, is an artery of consider-
able calibre, being nearly equal
in size to the continuation of
the femoral after the origin of
this great branch. It usually
arises from the outer and back
part of the femoral artery,
about an inch and a half below
Poupart’s ligament. At its com-
mencement, it inclines outwards
in front of the iliacus muscle,
to such an extent as to be visible for a short distance external to the
femoral artery ; it then runs downwards and backwards behind that
vessel, and passing between the long and great adductor muscles near
their femoral attachments, divides into terminal branches, which pierce
the great adductor, and ramify in the muscles at the back and outer
part of the thigh.

This artery lies successively in front of the iliacus, pectineus, adductor
brevis and adductor magnus muscles. The femoral and profunda veins

458 ARTERIES OF THE LOWER LIMB.

and the long adductor muscle are interposed between it and the femoral
trunk.

The named branches of the deep femoral artery are the external and
the internal circumflex, and the perforating arteries.

1. The external circumflex artery, a branch of considerable size, arises
from the outer side of the profunda near its origin, and passing out-
wards for a short distance beneath the sartorius and rectus muscles, and
through the divisions of the anterior crural nerve, divides into three sets
of branches.

(a) Transverse branches pass outwards over the crureus muscle, pierce the
vastus externus, so as to get between it and the femur, just below the great tro-
chanter, and reach the back part of the thigh, where they anastomose with the
internal circumflex and the perforating branches of the deep femoral, and with
the gluteal and sciatic branches of the internal iliac.

(b) Ascending branches, directed upwards beneath the sartorius and rectus,
and afterwards under the tensor muscle of the fascia lata, communicate with the
terminal branches of the gluteal, and with some of the external descending
branches of the circumflex iliac artery.

(c) Descending branches incline outwards and downwards upon the extensor
muscles of the knee, covered by the rectus muscle. They are usually three or
four in number, some being of considerable size; most of them are distributed to
the muscles on the fore-part of the thigh, but one or two can be traced beneath
the vastus extermus muscle as far as the knee, where they anastomose with the
arterial branches surrounding that joint.

2. The internal circumflex artery, smaller than the external circum-
flex, arises close to that branch from the inner and hinder part of the
deep femoral artery, and is directed backwards between the pectineus
and the psoas muscle to the inner side of the femur. On reaching the
tendon of the external obturator, along which the vessel passes to the
back of the thigh, it divides into two principal branches.

(a) The ascending branch is distributed partly to the adductor brevis and
gracilis, and partly to the external obturator muscle, near which it anastomoses
with the obturator artery.

(b) The transverse branch passes backwards above the small trochanter, and
appears on the back of the limb, between the quadratus femoris and great ad-
ductor muscles, where it supplies the hamstring muscles, and anastomoses with
the sciatic artery and with the superior perforating branches of the deep femoral
artery.

(c) An articular vessel, arising from the transverse branch opposite the hip-
joint, enters the joint through the notch in the acetabulam, beneath the trans-
verse ligament, and supplies the adipose tissue and the synovial membrane in that
articulation. Some offsets are guided to the head of the femur by the round
ligament. In some instances the articular branch is derived from the obturator
artery ; and sometimes the joint receives a branch from both sources.

3. The perforating arteries (perforantes) are branches which reach the
back of the thigh by perforating the adductor brevis and adductor
magnus muscles; they are four in number, including the terminal
branch of the parent vessel.

(a) The first perforating artery passes backwards below the pectineus muscle,
through the fibres of the adductor brevis and magnus, and is distributed to
both these adductor muscles, to the biceps and great gluteal muscle, and commu-
nicates with the sciatic and internal circumflex arteries.

(b) The second perforating artery, considerably larger than the first, passes
through the adductor brevis and magnus; after which it divides into ascending

PERFORATING BRANCHES OF THE PROFUNDA. 459

and descending branches, which ramify in the hamstring muscles, and commu-
nicate with the other perforating branches: an offset from it, named the nutrient
artery of the femur, enters the
medullary foramen of that
bone.

Fig. 294.—Posterion VIEW oF
THE ARTERIES OF THE PELVIS,
THIGH, AND PopniTEAL Space
(from Tiedemann).

a, the iliac crest ; 6, the great
sacro-sciatic ligament attached to
the tuberosity of the ischium : ¢,
great trochanter ; d, the integu-
ment close to the anus ; e, great
sciatic nerve ; f, the line from this
letter crosses the tendons of the
inner hamstring muscles ; y, head
of the fibula ; 1, gluteal artery ;
2, pudic ; 3, sciatic artery, giving
its branches to the short external
rotator muscles, to the sciatic
nerve, and to the upper part of
the long flexor muscles ; 4, first
perforating artery; 4’, its branches
to the flexor muscles ; 5, branches
of the second perforating; 6,
branches of the third perforating ;
7, popliteal artery, near this the
origin of the superior muscular
branches ; 8, placed on the ten-
don of the adductor magnus, near
the origin of the superior articular
branches ; 9, the anastomosis of
the external superior articular
with other branches ; 10, the
sural branches ; 11, the recurrent
of the anterior tibial artery.

(ec) The third perforating
artery pierces the adductor
magnus muscle, below the in-
sertion of the adductor longus,
and is distributed in a manner
similar to the second perfor-
ating artery.

(d) The fourth pexforating
artery, the termination of the
deep femoral artery, passing
backwards close to the linea
aspera, is distributed to the
short head of the biceps and
to the other hamstring mus-
eles, and communicates with
branches of the popliteal artery,
and with the lower perforating
arteries.

Muscular branches.—
In its course along the
thigh, the femoral artery gives off several branches to the contiguous

460 ARTERIES OF THE LOWER LIMB.

muscles. They vary in number from two to seven. They supply the
sartorius and the vastus internus with other muscles which are close to
the femoral artery: their size appears to bear an inverse proportion
to that of the descending branches of the external circumflex artery.

Anastomotic artery.— This branch arises from the femoral
artery when in Hunter’s canal. It pierces the anterior wall of that
canal and descends upon the tendon of the adductor magnus to the
inner condyle of the femur, giving off several branches, and covered by
some of the fibres of the vastus internus muscle ; it finally anastomoses
with the internal articular arteries, and with the recurrent branch of the
anterior tibial artery. It gives off the following branches.

(a) A superficial branch accompanies the long saphenous nerve beneath the
sartorius muscle to the integument on the inner side of the knee.

(6) The external branch, arising from the lower part of the vessel, crosses
over the femur, supplies offsets to the kmee-joint, and forms an arch a little
above the articular surface, by anastomosing with the superior external articular
artery.

Varieties of the Femoral Artery and Branches.—7?1n/.—Four instances
have been recorded of division of the femoral artery below the origin of the
profunda into two vessels, which subsequently were reunited near the opening of
the adductor magnus so as to form a single popliteal artery. In all these cases,
the arrangement of the vessels appears to have been similar. To one of them
(that first observed) special interest is attached, inasmuch as it was met with ina
patient operated upon for popliteal aneurism. (This case was treated by Charles
Bell, and recorded in ‘‘ The London Medical and Physical Journal,” vol. lvi.
p. 134. London, 1826.)

The femoral artery is occasionally replaced at the back of the thigh bya trunk
continuous with the internal iliac. Having passed from the pelvis through the
large sacro-sciatic notch, this trunk accompanies the great sciatic nerve along the
back of the thigh to the popliteal space, where its connections and termination
become similar to those of the vessel presenting the usual arrangement. Four
examples of this deviation from the common state of the blood-vessel have been
recorded. Reference is made to these in a Paper in vol. 36 of the Medico-Chirur-
gical Transactions, giving an account of a specimen of remarkable deformity
of the lower limbs of a man in whom the artery was so transposed on both
sides.

Branches.—The deep femoral is occasionally given off from the inner side of
the parent trunk, and more rarely from the back part of the vessel. Occasionally
it arises at a distance of less than an inch, and sometimes of more than two
inches, below Poupart’s ligament. It was even found by Richard Quain arising,
in one instance, above Poupart’s ligament, and in another four inches below it ;
but in the latter instance the internal and ex’ ernal circumflex arteries did not
arise from the profunda.

The eaternal circumflex branch sometimes arises directly from the femoral
artery ; or it may be represented by two branches, of which, in most cases, one
proceeds from the femoral, and one from the deep femoral : both branches, how-
ever, have been seen to arise from the deep femoral, and much more rarely, both
from the femoral artery.

The internal circumflex branch may be transferred to the femoral artery above
the origin of the profunda. Examples have also been met with in which the
internal circumflex arose from the epigastric, from the circumflex iliac, or from
the external iliac artery.

Many occasional branches have been seen arising from the femoral, as the deep
epigastric or an aberrant obturator ; more rarely an ilio-lumbar or a dorsalis penis,
an accessory profunda femoris, or an accessory external circumflex. The great
saphenous artery is an occasional vessel of some magnitude. It arises, when
present, either above or below the origin of the profunda, and running at first
between the vastus internus and adductor magnus, it pierces Hunter's canal to

THE POPLITEAL ARTERY. 46}

reach the inner aspect of the knee and accompanies the long saphenous vein
to the internal malleolus (Henle).

SURGICAL ANATOMY OF THE FEMORAL ARTERY.

The femoral artery may be tied in two parts of its course, either at the
apex of Scarpa’s triangle or in Hunter’s canal. The former situation is that
usually preferred by surgeons, owing to the superficial position of the vessel, and
its freedom from large branches. An incision about three and a half inches
long is made in the direction of the vessel, and so that the centre of the incision
shall be about four and a half inches below the middle of Poupart’s ligament.
The integument and fascia lata are cut through at once, and the sartorius
muscle exposed. The inner edge of that muscle is to be raised and turned
outwards, and the sheath of the artery scraped through. The femoral vein is
close behind the artery and only separated by a thin fibrous partition, and the
long saphenous nerve is to its outer side. The needle bearing the ligature is to be
passed from within outwards, its point being kept close to the artery.

To reach the artery in Hunter’s canal a much longer incision is needed, owing
to the greater depth of the vessel. The integuments are cut through over the
inner border of the sartorius muscle, which here lies directly in front of the
artery, avoiding at the same time the long saphenousvein. The fibrous structure
stretching over the vessels is then to be cut through and the artery exposed. The
ligature is passed asin the previous operation.

POPLITEAL ARTERY.

The popliteal artery placed at the back of the knee-joint extends
along the lower third of the thigh and the upper part of the leg, reaching
from the opening in the great adductor to the lower border of the
popliteus muscle. It is continuous above with the femoral, and divides
at the lower end into the anterior and posterior tibial arteries.

This artery at first inclines from the inner side of the limb to reach a
point behind the middle of the knee-joint, and thence continues to
descend vertically to its lower end. Lying deeply in its whole course,
it is covered for some distance at its upper end by the semimembranosus
muscle; a little above the knee it is placed in the popliteal space ;
inferiorly it is covered for a considerable distance by the gastrocnemius
muscle ; and at its termination by the upper margin of the soleus muscle.

At first the artery lies close to the inner side of the femur; in
descending, it is separated by an interval from the flat or somewhat
hollowed triangular surface at the lower end of the bone ; it then rests
on the posterior ligament of the knee-joint, and afterwards on the popli-
teus muscle.

Relation to Veins.—The popliteal vein lies close to the artery, behind
and somewhat to the outer side till near its termination, where it crosses
the artery and is placed somewhat on the inner side. The vein is
frequently double along the lower part of the artery, and, more rarely,
also at the upper part. The short saphenous vein, ascending into the
popliteal space over the gastrocnemius muscle, approaches the artery as
it is about to terminate in the popliteal vein.

Relation to the Nerve.—The internal popliteal nerve lies at first to the
outer side of the artery, but much nearer to the surface than the vessel :
the nerve afterwards crosses over the artery, and is placed behind and
to the inner side below the joint.

Brancues.—The branches of the popliteal artery may be arranged in
two sets, viz., the muscular and the articular.

1, The muscular branches are divided into a superior and an inferior

group.

x

462 ARTERIES OF THE LOWER LIMB.

(a) The superior branches, three or four in number, are distributed to the lower
ends of the hamstring muscles, as also to the vasti muscles, and anastomose with
the perforating and articular arteries,

Fig. 295.—View or tue PoprireaAL ARTERY AND ITS
BRaNcHES IN THE Ricut Lee (from Tiedemann). }

a, biceps muscle; 6, semi-membranosus; ¢, semi-
tendinosus ; 1, the popliteal artery ; 2, 3, the superficial
sural branches; 4, the outer, 5, the inner superior
articular branch; 6, the superior muscular ; 7, the
inferior muscular or deep sural branches.

(b) The inferior muscular branches, or sural arteries,
usually two in number, and of considerable size,
arise from the back of the popliteal artery, opposite
the knee-joint, and enter, one the outer and the other
the inner head of the gastrocnemius muscle, which
they supply, as well as the fleshy part of the plantaris
muscle.

Over the surface of the gastrocnemius will be found
at each side, and in the middle of the limb, slender
branches, which descend a considerable distance along
the calf of the leg, and end in the integument.
These small vessels (superficial sural) arise separately
from the popliteal artery, or from some of its
branches.

2. The articular arteries. Two of these
pass off nearly at right angles from the pop-
liteal artery, one to each side, above the flexure
of the joint, whilst two have a similar arrange-
ment below it, and a fifth passes from behind into the centre of the
joint.

(a) The upper internal articular artery winds round the femur just above the
inner condyle; and, passing under the tendon of the great adductor and the
vastus internus, divides into two branches; one of these, comparatively super-
ficial, enters the substance of the vastus, and inosculates with the anastomotic
branch of the femoral, and with the lower internal articular artery. The other
branch runs close to the femur, ramifies upon it, and also on the knee-joint, and
communicates with the upper external articular artery.

(b) The upper external articular artery passes outwards a little above the outer
condyle of the femur, under cover of the biceps muscle, and, after perforating
the intermuscular septum, divides into a superficial and a deep branch. The
latter, lying close upon the femur, spreads branches upon it and the articulation,
and communicates with the preceding vessel, with the anastomotic of the femoral,
and with the lower external articular artery; the superficial branch descends
through the vastus to the patella, anastomosing with other branches and assisting
in the supply of the joint.

(c) The lower internal articular artery passes downwards below the internal
tuberosity of the tibia, lying between the bone and the internal lateral ligament:
its branches ramify on the front and inner part of the joint, as far as the patella
and its ligament.

(d) The lower external articular artery takes its course outwards, under cover
of the outer head of the gastrocnemius in the first instance, and afterwards
under the external lateral ligament of the knee and the tendon of the biceps
muscle, passing above the head of the fibula. Having reached the fore part
of the joint, it divides near the patella into branches, some of which communi-
cate with the lower articular artery of the opposite side, and with the recurrent

THE ARTICULAR ARTERIES. 463

branch from the anterior tibial ; whilst others ascend, and anastomose with the
upper articular arteries.

(e) The middle or azygos articular artery is a small branch which arises opposite
the flexure of the joint, and, piercing the posterior ligament, supplies the crucial
ligaments and other structures within the articulation.

Fig. 296.—ANTERIOR VIEW OF THE Deep ARTERIAL
BRANCHES SURROUNDING THE KNEE-JOINT AND THEIR
Awnastomosss (from ‘liedemann). 4
a, the patellar articular surface of the femur; 6, the

posterior surface of the patella which, with the ligamentum
patella, has been turned down ; c, the head of the fibula ;
1 and 2, branches of the internal superior articular branch
of the popliteal ramifying on the periosteum, and anasto-
mosing with the external superior articular branch 3, and
with other arteries within and below the joint ; 4, branches
of the internal inferior articular; 5, external inferior
articular ; 6, recurrent of the anterior tibial artery.

Varieties. — Deviations from the ordinary condition
of the popliteal artery are not frequently met with.
The principal departure from the ordinary arrange-
ment consists in its high division into terminal
branches. Such an early division has been found to
take place most frequently opposite the flexure of
the kmee-joint, and not higher.

In a few instances, the popliteal artery has been
seen to divide into the anterior tibial and peroneal
arteries—the posterior tibial being small or absent.
In a single case, the popliteal artery was found to
divide at once into three terminal vessels, viz., the
peroneal and the anterior and posterior tibial arteries.

The azygos articular branch frequently arises from one of the other articular
branches, especially from the upper and external branch. There are sometimes
several small middle articular branches,

POSTERIOR TIBIAL ARTERY.

The posterior tibial artery is situated along the back part of the
leg, between the superficial and deep layers of muscles, and is firmly
bound down to the deep muscles by the fascia which covers them. It
extends from the lower border of the popliteus muscle, where it is
continuous with the popliteal artery, down to the inner side of the
calcaneum, where it terminates beneath the origin of the abductor
pollicis muscle by dividing into the external and internal plantar
arteries.

Placed at its origin opposite the interval between the tibia and
fibula, it approaches the inner side of the leg as it descends, and lies
behind the tibia; at its lower end it is placed midway between the
inner malleolus and the prominence of the heel. Very deeply seated
at the upper part, where it is covered by the fleshy portion of the
gastrocnemius and soleus muscles, it becomes comparatively superficial
towards the lower part, being there covered only by the integument and
two layers of fascia, and by the annular ligament behind the inner
malleolus. It lies successively upon the tibialis posticus, the flexor
longus digitorum, and, at its lower end, directly on the tibia and the
ankle-joint. Behind the ankle, the tendons of the tibialis posticus
and flexor longus digitorum lie between the artery and the internal

~

464 ARTERIES OF THE LOWER LIMB.

malleolus ; whilst the tendon of the flexor longus pollicis is to the outer
side of the artery.

Relation to the Veins and Nerve—The posterior tibial artery, like the
other arteries below the knee, is accompanied
by two vence comites. The posterior tibial
nerve is at first on the inner side of the artery,
but in the greater part of its course the nerve
is close to the outer side of the vessel.

Fig. 297.—DEEP PosTERIOR VIEW OF THE ARTERIES OF
1

THE Lee (from Tiedemann). 4

a, lower part of the adductor magnus muscle ; 4, origin
of the inner head of the gastrocnemius ; outer head and
plantaris ; d, tendon of the semimembranosus muscle ;
e, popliteus ; f, upper part of the soleus divided below its
origin from the head of the fibula; g, peroneus longus ;
h, flexor longus pollicis ; 7, flexor communis digitorum ;
1, upper part of the popliteal artery; 2, origin of the
superior articular branches; 3, origin of the inferior
articular branches ; the middle or azygos branch is seen
between these numbers; 4, division of the popliteal
artery into anterior and posterior tibial arteries ; 5, 5’,
posterior tibial ; 6, peroneal artery ; 6’, its continuation as
posterior peroneal ; between 5’ and 6’, the communicating
branch ; 7, caleaneal branches ; 8, external branches of
the metatarsal of the dorsalis pedis artery.

BRANCHES.—The posterior tibial artery
furnishes numerous small branches, and one
large branch—the peroneal artery.

Small Branches.—(a) Several muscular branches
arise from the posterior tibial artery, and are dis-
tributed principally to the deep-seated muscles in
its neighbourhood, besides one or two of considerable
size to the inner part of the soleus muscle.

(b) The nutrient artery of the tibia, which is the
largest of its kind in the body, arises from the pos-
terior tibial artery near its commencement, and,
after giving small branches to the muscles, enters
the nutrient foramen in the bone, and ramifies on
the medullary membrane. This vessel not unfre-
quently arises from the anterior tibial artery.

(ec) A communicating branch from the peroneal
artery, passing transversely, joins the posterior tibial
about two inches above the ankle-joint.

The peroneal artery lies deeply along the
back part of the leg, close to the fibula. Aris-
ing from the posterior tibial artery about an
inch below the lower border of the popliteus
muscle, it inclines at first obliquely towards
the fibula, and then descends nearly perpen-
dicularly along that bone and behind the outer
ankle, to reach the side of the os calcis. In
the upper part of its course, this artery is
covered by the soleus muscle and the deep fascia, and afterwards by
the flexor longus pollicis, which is placed over it as far as the outer

THE PERONEAL ARTERY. 465

malleolus ; below this point, the vessel is covered only by the common
integument and the fascia. The peroneal ariery rests at first against
the upper part of the tibialis posticus muscle, and afterwards in the
greater part of its course, it is surrounded by fibres of the flexor longus
pollicis, lying close inside the projecting posterior ridge of the fibula.
Descending beyond the outer malleolus, it terminates in branches on
the outer surface and back of the os calcis.

Branches.—(a) Muscular branches from the upper part of the peroneal artery
pass to the soleus, the tibialis posticus, the flexor longus pollicis, and the peronei
muscles.

(b) A nutrient artery enters the fibula.

(c) The anterior peroneal artery arises about two inches aboye the outer
malleolus, and, immediately piercing the interosseous membrane, descends along
the front of the fibula, covered by the peroneus tertius muscle, and, dividing into
branches, reaches the outer ankle, and anastomoses with the external malleolar
branch of the anterior tibial artery. It supplies vessels to the ankle-joint, and
ramifies on the front and outer side of the tarsus, inosculating more or less freely
with the tarsal arteries.

(d) The terminal branches anastomose with the external malleolar and with
the tarsal arteries on the outer side of the foot; and behind the os calcis with
ramifications of the posterior tibial artery.

(e) The communicating branch, lying close behind the tibia, about two inches
from its lower end, is a transverse branch situated close to the bones, which con-
nects the peroneal with the posterior tibial artery.

Varieties.—The posterior tibial artery, as well as the anterior tibial, is
lengthened in those instances in which the popliteal artery divides higher up
than usual. Not unfrequently the posterior tibial artery is diminished in size,
and is subsequently reinforced either by a transverse branch from the peroneal
in the lower part of the les, or, in rare instances, by two transverse vessels, one
crossing close to the bone, and the other over the deep muscles. In other
instances the posterior tibial may exist only as a short muscular trunk in the
upper part of the leg, while an enlarged peroneal artery takes its place from
above the ankle downwards into the foot.

The peroneal artery has been found to arise lower down than usual, about three
inches below the popliteus muscle; and, on the contrary, it sometimes commences
higher up from the posterior tibial, or even from the popliteal artery itself. In
some cases of high division of the popliteal artery, the peroneal artery is trans-
ferred to the anterior tibial. It more frequently exceeds than falls short of
the ordinary dimensions, being enlarged to reinforce the posterior tibial. In
those rare instances in which it is lost before reaching the lower part of the leg,
a branch of the posterior tibial takes its place. The anterior peroneal branch is
sometimes enlarged to compensate for the small size of the anterior tibial artery
in the lower part of the leg, or to supply the place of that artery on the dorsum
of the foot; or it may be absent and be replaced by the anterior tibial. In a
singular case, recorded by Otto, the peroneal artery was wholly wanting.

PLANTAR ARTERIES.

The external and internal plantar arteries are the branches into
which the posterior tibial divides in the hollow of the calcaneum, where
it is covered by the origin of the abductor pollicis.

The internal plantar artery, much smaller than the external, is
directed forwards, alone the inner side of the foot. Placed at first
under cover of the abductor pollicis, it passes forwards in the groove
between that muscle and the short flexor of the toes, near the line
separating the middle from the inner portion of the plantar fascia, and

on reaching the extremity of the first metatarsal bone, considerably
VOL. I. H H

x

466 ARTERIES OF THE LOWER LIMB.

diminished in size, it terminates by running along the inner border of
the great toe, anastomosing with the digital branches.

Fig. 298.—SvuPERFICIAL VIEW OF THE ARTERIES IN
THE SoLE or THE Ricur Foor (from Tiedemann). 4$

a, tuberosity of the calcaneum close to the origin of
the flexor brevis digitorum (cut short) and the ab-
duetor pollicis, of which a part is removed, to show
the plantar arteries ; 6, abductor pollicis ; c, abductor
minimi digiti ;-d, tendon of the flexor pollicis longus ;
e, tendon of the flexor communis longus ; e’, its four
slips, close to the lumbricales muscles, passing on to
perforate the tendons of the flexor brevis; jf, flexor
accessorius ; g, flexor brevis minimi digiti : 1, posterior
tibial dividing into the plantar arteries ; 2, 2’, external
plantar ; 3, internal plantar ; 3’, the same passing for-
ward to communicate with 4, the digital branch for the
great toe, derived from the dorsal artery of the foot ; 5,
first digital or external plantar branch to the fifth toe ; 6,
placed in the angle of division of the second plantar
digital artery, between the fourth and fifth toes ; 7, the
third plantar digital artery dividing similarly between
the third and fourth toes ; 8, the fourth plantar digital
artery dividing similarly between the second and third
toes; 9, the plantar digital artery dividing similarly
between the first and second toes ; 10, internal plantar
artery of the great toe ; 11, calcaneal branches of the
plantar arteries, anastomosing with 12, the calcaneal
branches of the posterior peroneal artery.

Branches.—The internal plantar artery gives off
numerous small twigs, which may be distinguished
in sets as follows:—(a@) muscular branches to
the abductor pollicis and flexor brevis digitorum ;
(b) offsets which incline towards the inner border of the foot, and communi-
cate with branches of the dorsal arteries; and (c) cutaneous offsets which
appear in the furrow between the middle and inner portions of the plantar
fascia.

The external plantar artery, of considerable size, at first inclines
outwards and then forwards, to reach the base of the fifth metatarsal
bone: it then turns obliquely inwards across the foot, to gain the
interval between the bases of the first and second metatarsal bones,
where it joins, by a communicating branch, with the dorsal artery of
the foot ; and thus is completed the plantar arch, the convexity of which
is turned forward. At first the artery is placed, together with the
external plantar nerve, between the calcaneum and the abductor pol-
licis ; further on it lies between the flexor brevis digitorum and flexor
accessorius. As it turns forwards it lies in the interval between the
short flexor of the toes and the abductor of the little toe, being placed
along the line separating the middle from the external portion of the
plantar fascia, and covered by that membrane. The remainder of the
artery, which turns inwards and forms the plantar arch, is placed deeply
against the interosseous muscles, and is covered by the flexors of the
toes and the lumbricales muscles.

Branches.—A. Jn its course to the fifth metacarpal bone the external plantar
artery gives off (a) branches to the skin of the heel; (/) numerous muscular
branches ; (¢) small offsets which run outwards over the border of the foot, and

LS

THE EXTERNAL PLANTAR ARTERY. 467

anastomose with the dorsal arteries; and (d) others which appear in the furrow
between the middle and outer divisions of the plantar fascia.
B. From the plantar arch are given off the following more important branches.
(a) The posterior perforating branches, three in number, pass upwards through
the back part of the three outer interosseous spaces, between the heads of the
dorsal interosseous muscles, and on reaching the dorsum of the foot inosculate
with the interosseous branches of the metatarsal artery.

Fig. 299.—Drrr view or THE ARTERIES IN THE SOLE
oF THE Rigur Foot (from Tiedemann). 4

All the muscles have been removed. a, the calcaneal
tuberosity ; 4, the scaphoid bone and end of the calcaneo-
scaphoid ligament; ¢, to a, calcaneo-cuboid ligament ;
d, its deep part ; e, scaphoido-cuneiform ligament ; f,
one of the sesamoid bones of the great toe ; 1, posterior
tibial artery dividing into the plantar arteries; 2, 2’,
external plantar artery ; 2’, 2", deep plantar arch termi-
nating by communication with the dorsal artery of the
foot ; 3, 3’, internal plantar artery ; 3”, its communica-
tion with the internal digital of the great toe; 4,
branches of the internal plantar to the inside of the foot ;
5, 5’, first digital or external plantar branch of the fifth
toe ; 6, second plantar digital artery ; 6’, interval of the
division of the same between the fourth and fifth toes ;
7, third plantar digital; 7’, its distribution to the third
and fourth toes; 8, fourth plantar digital ; 8’, its dis-
tribution to the second and third toes; 9, fifth plantar
digital ; 9’, its distribution to the first and second toes ;
10, internal plantar digital branch of the great toe ;
at the upper numbers, 6, 7, and 8, the posterior per-
forating branches of the interosseous arteries are par
tially indicated ; at 2", the large communication between
the plantar arch and the dorsalis pedis artery; above
6’, 7, and 8’, are situated the anterior perforating
arteries, not represented in the figure; 11, and 12,
calecaneal branches of the plantar and posterior peroneal
arteries.

(0) The digital branches are four in number. The
first digital branch inclines outwards from the outer-
most part of the plantar arch, opposite the end of the fourth metatarsal space,
crosses under cover of the abductor minimi digiti, and runs along the outer
border of the phalanges of the little toe. The second digital branch passes for-
wards along the fourth metatarsal space, and near the cleft between the fourth
and fifth toes divides into two vessels, which course along the contiguous.
borders of those toes, and end on the last phalanges. The third digital branch
is similarly disposed of on the fourth and third toes. The fowrth ends in like
manner on the third and second toes.

The digital artery which supplies the opposed sides of the first and second toes,
and that which runs on the inner side of the first toe, arise deeply between the
first and second metatarsal bones, usually from that part of the arch which is
formed by the end of the dorsal artery of the foot.

Thus, as in the fingers, coliateral arteries pass along the sides of the flexor
surface of each of the toes. Near the base of the last phalanx these inosculate
so as to form an arch, from the convexity of which minute vessels pass forwards
to the extremity of the toe, and to the matrix of the nail.

(ec) An anterior perforating branch is sent upwards by each of the digital
arteries of the three outer interspaces near its bifurcation, to communicate with
the corresponding digital branch of the metatarsal artery of the dorsum of the
foot.

Varieties.—The posterior perforating branches, which are usually uo small

\ HH 4

468 ARTERIES OF THE LOWER LIMB.

vessels, are sometimes enlarged, and furnish the interosseous arteries on the upper
surface of the foot ; the metatarsal branch of the dorsal artery, from which the
interosseous arteries are usually derived, being in
that case very small.

Fig. 300.—ANTERIOR VIEW OF THE ARTERIES OF THE

Lec anp Dorsum oF THE Foor (from Tiedemann). 4

The tibialis anticus muscle is drawn towards the inner
side so as to bring the anterior tibial artery into view ;
the extensor proprius pollicis, the long common extensor
of the toes, and the peroneus tertius muscles in their
lower part, and the whole of the extensor communis
brevis, have been removed. 1, external superior articular
branch of the popliteal artery, ramifying on the parts
surrounding the knee, and anastomosing with the other
articular branches and with 2, the recurrent branch of
the anterior tibial artery ; 3, 3, anterior tibial, giving off
muscular branches on each side; 4, dorsal artery of
the foot ; 5, external anterior malleolar artery coming
off from the anterior tibial, and anastomosing with
the anterior peroneal artery which is seen descending
npon the lower part of the fibula : the internal malleolar
is represented proceeding from the other side of the
anterior tibial artery ; 6, the tarsal branch of the dorsal
artery, represented in this instance as larger than usual
and furnishing some of the branches of the next artery ;
7, the metatarsal branch, giving off the dorsal inter-
osseous arteries: (in the first interosseous space the
dorsal artery of the foot is seen to give off the anasto-
mosing branch which unites with the deep plantar arch ;)
between 8, and 8, the collateral branches of the dorsal
digital arteries.

ANTERIOR TIBIAL ARTERY.

The anterior tibial artery, placed along
the fore part of the leg, is at first deeply
seated, but gradually approaches nearer to the
surface as it descends. It extends from the
division of the popliteal artery to the bend of
the ankle ; whence it is afterwards prolonged
to the interval between the first and second
metatarsal bones, under the name of dorsal
artery of the foot.

The anterior tibial artery is at first directed
forwards to reach the anterior surface of the
interosseous ligament, passing through the
divided upper end of the tibialis posticus, and
through the interval left unoccupied by the
interosseous ligament. It then extends ob-
liquely downwards to the middle of the ankle-
joint, in a direction which may be nearly
indicated by a line drawn from the inner
side of the head of the fibula to midway
between the two malleoli. Lying with the
tibialis anticus on its inner side, and having
the extensor communis digitorum and, lower
down, the extensor proprius pollicis on its outer side, the vessel is

THE ANTERIOR TIBIAL ARTERY. 469

deeply placed at the upper part of the leg, where those muscles
are fleshy ; but it is comparatively superficial below, between their
tendons, and comes forward upon the tibia. At the bend of the ankle
it is covered by the annular ligament, and is crossed from without
inwards by the tendon of the extensor proprius pollicis. In its oblique
course downwards the anterior tibial artery lies at first close to the
interosseous ligament, and is then at a considerable distance from the
spine of the tibia ; but in descending it gradually approaches that ridge,
and towards the lower part of the leg is supported on the anterior surface
of the bone

Relation to Veins and Nerves——The anterior tibial artery is accompa-
nied by two veins (venze comites). The anterior tibial nerve, coming
from the outer side of the head of the fibula, approaches the artery at
some distance below the place where the vessel appears in front of the
interosseous ligament. Lower down, the nerve for the most part lies in
front of the artery, but often changes its position from the one side of
the vessel to the other.

Branches.—Besides numerous small muscular branches, the anterior tibial
artery furnishes the following.

(a) The recurrent artery, given off as soon as the anterior tibial reaches the
front of the leg, ascends through the fibres of the tibialis anticus, and, ramifying
on the outside and front of the knee-joint, anastomoses with the inferior articular
and other branches of the popliteal artery.

(6) The maileolar arteries. two in number, external and internal, are given off
near the ankle-joint, but are very variable in size and mode of origin. The
internal branch passes beneath the tendon of the tibialis anticus to the inner
ankle, and communicates with branches of the posterior tibial artery. The
external branch passes outwards under the tendon of the common entensor of
the toes, and anastomoses with the anterior division of the peroneal artery, and
also with some ascending or recurrent branches from the tarsal branch of the
dorsal artery of the foot——These malleolar arteries supply articular branches to
the neighbouring joinis.

DORSAL ARTERY OF THE FOOT.

The dorsal artery of the foot (dorsalis pedis), the continuation of
the anterior tibial artery, extends from the termination of that vessel
at the bend of the ankle, to the posterior end of the first metatarsal
space. At this spot it divides into two branches, of which one pro-
ceeds forwards in the first interosseous space, whilst the other dips into
the sole of the foot, and terminates by inosculating with the plantar
arch. The dorsal artery of the foot les in the interval between the
tendon of the proper extensor of the great toe, and that of the long
extensor of the other toes ; and is covered by a deep layer of fascia,
which binds it to the parts beneath. Near its end it is crossed by the
innermost tendon of the short extensor of the toes.

Two veins accompany this artery ; the anterior tibial nerve lies on
its outer side.

BRANCHES.—The principal branches of the dorsal artery of the foot
are directed outwards and forwards upon the tarsus and metatarsus,
and are named accordingly. Some small offsets also run obliquely
inwards, and ramify upon the inner side of the foot.

(a) The tarsal branch arises from the artery usually where it crosses
the scaphoid bone, but its point of origin varies in different instances.

‘

470 ARTERIES OF THE LOWER LIMB,

It inclines forwards and outwards upon the tarsal bones covered by the
short extensor muscle of the toes, then curving backwards towards the
cuboid bone, divides into branches which take
different divections over the tarsus.

Fig. 301.—ANTERIOR virw OF THE ARTERIES OF THE
Leg AnD Dorsum or tun Foor (from Tiedemann). }

The tibialis anticus muscle is drawn towards the inner
side so as to bring the anterior tibial artery into view,
the extensor proprius pollicis, the long common extensor
of the toes, and the peroneus tertius muscles in their
lower part, and the whole of the extensor communis
brevis, have been removed. 1, external superior articular
branch of the popliteal artery, ramifying on the parts
surrounding the knee ; and anastomosing with the other
articular branches, and with 2, the recurrent branch of
the anterior tibial artery ; 3, 3, anterior tibial, giving
off muscular branches on each side; 4, dorsal artery
of tke foot ; 5, external anterior malleolar artery coming
off from the anterior tibial and anastomosing with the
anterior peroneal artery which is seen descending upon
the lower part of the fibula; the internal malleolar is
represented proceeding from the other side of the anterior
tibial artery ; 6, the tarsal branch of the dorsal artery,
represented in this instance as larger than usual and
furnishing some of the branches of the next artery; 7,
the metatarsal branch, giving off the dorsal interosseous
arteries ; (in the first interosseous space the dorsal artery
of the foot is seen to give off the anastomosing branch
which unites with the deep plantar arch ;) between 8
and 8, the collateral branches of the dorsal digital
arteries.

Its branches supply the extensor brevis
‘digitorum muscle and the tarsal joints, and
anastomose with the external plantar, the
metatarsal, the external malleolar, and the
peroneal arteries.

(>) The metatarsal artery arises farther
forwards than the preceding vessel, and is
directed outwards like it, beneath the short
extensor muscle. Sometimes there are two
metatarsal arteries, the second being of smaller
size; and not unirequently, when there is but
a single vessel of this name, it arises in com-
mon with the tarsal artery. Its direction is
necessarily influenced by these circumstances ;
being obliqne when it arises far back, and
almost transverse when its origin is situated
farther forwards than usual. It anastomoses
with the tarsal and external plantar arteries,
and gives off interosseous branches.

The three interosscous branches are smail straight
vessels which pass forwards along the three outer
interosseous spaces, resting upon the dorsal inter-
osseous muscles. Somewhat behind the clefts be-
twveen the toes cach divides into two branches, which run forward along the
contiguous borders of the corresponding toes, forming their dorsal collateral

VARIETIES OF THE ANTERIOR TIBIAL ARTERY. 471

branches. Moreover, from the outermost of these intercsseous arteries a small
branch is given off, which gains the outer border of the little toe, and forms its
external collateral branch. These arteries communicate with the plantar arch
opposite the fore part of the interosseous spaces, by means of the anterior
perforating branches, and at the back part of the interosseous spaces, by the
posterior perforating branches.

(c) The dorsal artery of the great toe (dorsalis hallucis) is con-
tinued forwards from the dorsal artery of the foot at the point where it
dips down to the sole. This branch runs along the outer surface of the
first metatarsal bone, and furnishes the small dorsal divital vessels of
the great toe and adjacent side of the second toe.

(d) The plantar digital branch of the first space is given off
from the dorsal artery between the heads of the first interosseous
muscle, near the inosculation with the plantar arch, and passing for-
wards divides into two smaller branches which proceed along the con-
tiguous sides of the first and second toe.

(e) The plantar digital branch for the inner side of the great
toe crosses beneath the first metatarsal bone, and runs along the inner
side of the great toe on its plantar surface.

Varieties of the Anterior Tibial Artery.—Ovigin.—In cases of early division
of the popliteal artery, the place of origin of the anterior tibial is necessarily
higher up than usual, being sometimes found as high as the bend of the knee-
joint. In some of these cases (the posterior tibial artery being small or wanting),
the anterior tibial is conjoined with the peroneal artery. When the anterior
tibial arises higher than usual, the additional upper part of the vessel has been
seen resting on the posterior surface of the popliteus muscle, and it has been
likewise found between that muscle and the bone.

Course.—The anterior tibial artery, having its usual place of origin, has been
found to deviate outwards towards the margin of the fibula in its course along the
front of the leg, and then to return to its ordinary position beneath the annular
ligament in front of the ankle-joint. This artery has been also noticed by
Pelletan and by Velpeau to approach the surface at the middle of the leg, and to
continue downwards from that point, covered only by the fascia and integument.
Velpeau states that he found the artery to reach the fore part of the leg by
passing round the outer side of the fibula. (Pelletan, “‘ Clinique Chirurgicale,”’
&e., p. 101: Paris, 1810. Velpeau, “ Nouveaux Elémens de Médecine Opératoire,”
&e., t. 1., pp. 1387 and 537 : Paris, 1837.)

Size.—This vessel more frequently undergoes a diminution than an increase of
size,

It may be defective in various degrees. Thus the dorsal branch of the foot
may fail to give off digital branches to the great and second toes, which may
be then derived from the internal plantar division of the posterior tibial. In a
farther degree of diminution the anterior tibial ends in front of the ankle or at
the lower part of the leg; its place being then taken by the anterior division
of the peroneal artery, which supplies the dorsal artery of the foot; the two
vessels (anterior tibial and anterior peroneal) being either connected together or
separate.

Two cases are mentioned by Allan Burns, in which the anterior tibial artery
was altogether wanting, its place in the leg being supplied by perforating branches
from the posterior tibial artery, and on the dorsum of the foot by the anterior
peroneal artery.

The dorsal artery of the foot is occasionally larger than usual; in that case
compensating for a defective condition of the internal plantar branch from the
posterior tibial artery.

This artery has been repeatedly found to be curved outwards between its com-
mencement at the lower border of the annular ligament and its termination in
_ the first interosseous space,

A472 THE SYSTEMIC VEINS.

THE SYSTEMIC VEINS.

The systemic veins commence by small branches which receive the
blood from the capillaries throughout the body, and unite to form
larger vessels, which end at last by pouring their contents into the
right auriele of the heart through two large venous trunks, the supe-
rior and inferior ven cave. The blood which nourishes the sub-
stance of the heart itself, is also returned by the coronary veins to the
right auricle.

The veins, however, which bring back the blood from the stomach,
intestines, spleen, and pancreas, have an exceptional destination, not
conveying the blood directly to the heart, but joining to form a single
trunk—the portal vein, which ramifies after the manner of an artery
in the substance of the liver, and carries the blood within it to the
capillaries of that organ. From these the blood passes into the ulti-
mate twigs of the hepatic veins, and is conveyed by these veins into the
inferior vena cava. The veins thus passing to the liver constitute the
portal system.

The anastomoses of veins are much larger and more numerous than
those of arteries. The veins of many parts of the body consist of a
subcutaneous and a deep set, which have very frequent communications
with each other. In some parts of the body, chiefly in the limbs and
at the surface, the veins are provided with valves, whilst in others no
valves exist.

The systemic veins are naturally divisible into two groups: firstly, those
from which the blood is carried to the heart by the superior vena cava,
viz., the veins of the head and neck and upper limbs, together with
those of the spine and a part of the walls of the thorax and abdomen,
with which may be associated also the veins of the heart ; and secondly,
those from which the blood is carried to the heart by the inferior vena
cava, viz., the veins of the lower limbs, the lower part of the trunk, and
the abdominal viscera. (For a general representation of the venous
system, see fig. 240, at p. 344.)

SUPERIOR VENA CAVA.

The superior vena cava conveys to the heart the blood which is
returned from the head, the neck, the upper limbs, and the thorax. It
is formed by the union of the right and left brachio-cephalic veins. It
extends from a little below the cartilage of the first rib on the right
side of the sternum to the base of the heart, where it opens into the
right auricle. Its course is slightly curved, the convexity of the curve
being turned to the right side. It has no valves. At about an inch
and a half above its termination, it is invested by the fibrous layer of
the pericardium, the serous membrane being reflected over it. The
upper vena cava lies immediately in front of the right pulmonary
vessels, and between the right lung and the aorta, which partly overlap
it. It receives several small veins from the pericardium and the medias-
tinum ; and lastly, it is joined by the right azygos vein, immediately
above the place where it becomes invested by the pericardium.

Varieties.—In several instances, the two innominate veins, which usually
join to form the vena cava superior, have been seen to open separately into the
right auricle. This peculiarity is explained by reference to the development of

THE SUPERIOR VENA CAVA. 473

the parts, and will be more fully referred to at p. 485, in connection with the
description of the great cardiac vein. The superior vena cava in one case has

been seen to be joined by one of the pulmonary
veins (Meckel). In several cases two superior
ven cave have been found,a right and a
left, the left always opening into the left
auricle, and in one case being joined by a
pulmonary vein. (Hyrtl, Gruber, Luschka.)

Fig. 302.—Sxetcnw oF THE PrincipaAL VENOUS
TRUNKS, TOGETHER WITH THE THorAcic Ducr. §

a, the basilar process of the occipital bone,
through which and the temporal bones a trans-
verse incision has been made so as to lay open the
jugular foramen on both sides ; b, the fifth cervi-
cal vertebra ; c, the first rib ; d, the sixth ; e, the
twelfth ; f,-the fifth lumbar vertebra; 1, vena
cava superior divided at the place of its entrance
into the right auricle; 2, right, 2’, left subcla-
vian veins ; 3, right internal jugular vein ; 3’, 3’,
lower part of the lateral sinuses of the dura
mater ; that of the right side shows at its junction
with the jugular. vein the bulb which lies in
the jugular depression of the temporal bone; 4,
right, and 4’, left external jugular veins ; 5, right,
and 5’, left vertebral veins, anastomosing with 5",
external vertebral veins, before joining the sub-
clavian veins ; 6, placed on left subclavian vein
below the opening of the last, and of the thoracic
duct ; below 0, the inferior thyroid veins ; 7, 7’, the
internal mammary veins; 8, the left superior
intercostal vein joining the left brachio-cephalic
vein, and anastomosing below with intercostal veins
which join the trunk of the azygos; the right
superior intercostal vein is seen joining the azygos
vein ; 9, main or right azygos vein ; 9’, the left
azygos, represented here as crossing the vertebral
column on the eighth vertebra ; 10, the thoracic
duct; 11, trunk of the inferior vena cava at
the place of junction of the renal veins; the vena
cava is seen dividing on the fourth lumbar vertebra
into the two common iliac veins ; 12, the union
of the left azygos vein with the left renal vein ; 13,
on the right side, the commencement of the right
azygos vein in the lumbar region, joined by several
lumbar veins; 13’, the commencement of the
azygos vein of the left side, joining similar veins
on that side ; 14, 14’, the external iliac veins ;
15, placed on the promontory of the sacrum, points
on either side to the prolongation of the lower
branches of the right and left lumbar veins into
the pelvis, and their union with sacral and other
branches of the internal iliac veins.

INNOMINATE OR BRACHIO-CEPHALIC
VEINS.

The blood returned from the upper
limbs through the subclavian veins, and
from the head and neck by the jugular
veins, is poured into two trunks, named
the brachio-cephalic or innominate veins.

4

These vessels, resulting from

474 THE SUPERIOR VENA CAVA.

the union of the subclavian with the internal jugular vein at each
side, commence opposite the inner ends of the clavicles, and terminate
a little below the cartilage of the first rib on the right side, where,
by uniting, they form the upper vena cava. The right vein is very
short, and nearly vertical in its direction; it is in apposition, on the
right side, with the pleura and the upper part of the right lung. The
vein of the left side, about three times longer than the right vein,
pursues a course from left to right, at the same time inclining some-
what downwards: it crosses behind the upper part of the first bone of
the sternum, separated from it by the sterno-hyoid and sterno-thyroid
muscles, and by the thymus gland or its remains ; it lies in front of the
three primary branches given off from the arch of the aorta, and rests
upon the highest part of the arch. The innominate veins have no
valves.

LATERAL TRIBUTARIES.—(a@) The inferior thyroid veins emerge
from a venous plexus situated on the thyroid body—those of opposite
sides communicating by small branches across the trachea. The vein
of the left side descends in front of the trachea, behind the sterno-
thyroid muscles, and ends in the left brachio-cephalic or innominate
vein: that of the right side inclines outwards in some degree, and
opens into the corresponding brachio-cephalic vein, or into the angle of
union between it and the vessel of the opposite side. In their course
these veins receive inferior laryngeal and tracheal branches.

(0) The internal mammary veins follow exactly the course of the
arteries of the same name—two veins accompanying each of the arte-
ries. The two companion veins of the artery arise by small branches,
derived from the fore part of the walls of the abdomen, where they
anastomose with the epigastric veins; from thence proceeding
upwards between the cartilages of the ribs and the pleura, they
receive the anterior intercostal veins which correspond with the
branches of the internal mammary artery, together with some small
diaphragmatic, thymic, and mediastinal veins, and these finally uniting
into a single trunk, each vein terminates in the brachio-cephalic of its
own side.

(c.) The superior intercostal veins.—The right superior intercostal
vein receives the blood from the first two or three spaces, communi-
cating with the vessel in the space next below, and opens into the in-
nominate trunk of the same side, or into the vena cava. Frequently the
veins at the right side, corresponding with the superior intercostal
artery, pass downwards separately, to open into the azygos vein, as that
vessel arches forwards to join the upper vena cava: the separate vein
thus formed is inferior in size to that on the left side. The deft superior
intercostal vein varies in length in different persons, being small when
the azygos minor is large, and vice versd. Usually it receives the veins
from the three or four upper spaces, and is then directed forwards over
the left side of the spinal column and the aorta to open into the left in-
nominate vein. It receives in its course the left bronchial vein. The
left vein is sometimes directed downwards to join an azygos vein on its
own side.

A small fibrous cord is frequently found joining the trunk of the superior
intercostal vein with the coronary sinus of the heart. This is the remains of
the left duct of Cuvier, a foetal structure to be afterwards described.

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)

THE FACIAL VEIN. 475

VEINS OF THE HEAD AND NECK.

The blood returning from the head and neck flows on each side into
two principal veins, the external and internal jugular. The veins of the
head and neck have generally no valves. The external jugular vein is
provided with a valve at its entrance into the subclavian vein, and in
most cases with another about the middle of its course: and the
internal jugular is also furnished with valves near its junction with the
subclavian. ‘hese valves, however, are not sufficient to stop the regur-
gitation of the blood, or the passage of injections from below upwards.

The veins on the exterior of the cranium and face converge and unite,
so as to form two trunks, the facial and the temporal veins.

The facial vein lies obliquely along the side of the face, extending
from the inner margin of the orbit downwards and outwards to the ante-
rior border of the masseter muscle. Resting on the same plane as the
facial artery, but farther back, and less tortuous, it has very nearly the
same relations to contiguous parts. It commences at the side of the
root of the nose by a vein formed by the junction of branches from the
forehead, eyebrow, and nose, and increases by receiving others during
its course. Below the jaw it inclines outwards and backwards, covered
by the cervical fascia and the platysma muscle : and soon unites with
a large branch of communication derived from the temporal vein, to
form the ¢emporo-maxillary or common facial yein, a short vessel of con-
siderable size, which joins obliquely the trunk of the internal jugular.

Fig. 303.—Vizw or THE SupER- Fig. 303.
FICIAL VEINS OF THE HEAD
AND NECK.

1, sterno-mastoid muscle ; a,
facial vein; 6, temporal vein ;
c, transverse facial ; d, posterior
auricular ; e, internal maxillary
vein ; f, external jugular vein ;
g, posterior external jugular ; h,
anterior jugular; 2, posterior
scapular and suprascapular veins;
i. internal jugular vein ; J, occi-
pital vein ; m, subclavian vein ;
above the inner side of the orbit
are shown the frontal and supra-
orbital veins, and their descend-
ing branches to anastomose with
the angular or terminal branch
of the facial vein.

Tributaries.—(a) The fvon-
talvein commenceson the roof
of the skull by branches, which
descend obliquely inwards up-
on the forehead, maintaining
communicationsin their course
with the anterior branches
of the temporal vein. It
descends vertically, parallel with the corresponding vessel of the opposite side,
with which it is connected by transverse branches, and ends in the angular vein.
. In some instances the veins of the two sides unite and form a short trunk, which
again divides into two branches at the root of the nose, As it descends from the

4

476 VEINS OF THE HEAD AND NECK.

forehead, the frontal vein receives a branch from the eyebrow, and some, of
smaller size, from the nose and upper eyelid.

(b) The supra-orbital vein (vy. supercilii) runs inwards in the direction of
the eyebrow, covered by the occipito-frontalis muscle. Its branches are con-
nected externally with those of the external palpebral and superficial temporal
veins : in its course it receives branches from the contiguous muscles and in-
tegument, and at the inner angle of the orbit inclines downwards to terminate
in the frontal vein.

(c) The angular vein, formed by the junction of the supra-orbital and frontal
veins, is perceptible beneath the skin as it rums obliquely downwards and
outwards near the inner margin of the orbit, resting against the side of the
nose at its root. This vessel receives on the inner side the nasal veins, which
pass upwards obliquely to join it from the side and ridge of the nose; whilst
some small superior palpebral veins open into it from the opposite direction.
On a level with the lower margin of the orbit it becomes continuous with the
facial vein.

(d) The inferior palpebral veins, two or three in number, are derived from the
lower eyelid, from the outer side of the orbit, and from the cheek. They pass in
a direction obliquely inwards above the zygomatic muscle, and then turn beneath
it previously to their termination.

(e) Communicating branches from the pterygoid plexus (deep facial, anterior
internal maxillary) and also some branches proceeding from the orbit, furnished
by the infra-orbital of the internal maxillary vein, join the facial on a level with
the angle of the mouth.

(f) Labial, buccal, massctcric and mental branches join the facial below the
angle of the mouth.

(g) The ranine vein is a small vessel which lies along the under surface of the
tongue, close to the franum lingue, in apposition with the artery of the same
name: its course is backwards and outwards, between the mylo-hyoid and hyo-
glossus muscles, to open into the facial vein, or sometimes into the lingual.

(h) The swbmental vein, larger than the preceding, commences below the chin ;
it receives branches from the submaxillary gland, and from the mylo-hyoid
muscle, and, keeping close under cover of the margin of the jaw-bone, joins the
facial vein ; but in some instances it enters the lingual or superior thyroid vein.

(i) Submaxillary branches from the gland join the facial vein either separately
or united into one trunk.

(j) The palatine vein returns the blood from the plexus surrounding the tonsil
and from the soft palate; it passes downwards, deeply seated by the side of
the pharynx, to join one of the preceding veins, or terminate in the facial
separately.

The temporal vein, a vessel cf considcrable size, descends in front of
the external auditory tube, reaching from the zygoma, upon which it
rests, to the angle of the jaw. It results from the union of branches
which are spread out upon the side of the head, some superficially, and
others deeply seated. The swperficial branches commence upon the
arch of the skull, where they communicate with the ramifications of
the frontal and occipital veins, as well as with those of the corre-
sponding vein of the opposite side. Descending on the surface of the
temporal fascia, they converge ; those from the fore part inclining a
little backwards, while the posterior branches run forwards over the
ear; and the two sets joining together above the zygoma form the
trunk of the temporal vein. The deeper branches, arising in the sub-
stance of the temporal muscle, unite to form a vein of some size, called
the middle temporal, to distinguish it from branches still more deeply
placed, and which open into the internal maxillary vein. The middle
temporal vein falls into the common temporal trunk at its commence-
ment above the zygoma. The temporal vein gradually sinks into the

THE INTERNAL MAXILLARY VEIN. 477

substance of the parotid gland as it descends behind the ramus of the
jaw. Beneath the angle of that bone, it divides into two vessels, one
of which turns backwards, and forms the commencement of the external
jugular vein, while the other communicates with the facial vein near
its termination.

Tributaries.—These are numerous :—(@) parotid branches from the parotid
gland ; (0) articular, from the articulation of the jaw; (¢) anterior auricular
veins from the external ear; (d) the transverse facial, a branch of consider-
able size, corresponding with the transverse facial artery; (¢) the posterior
auricular directed forwards from behind, and joined by the stylo-mastoid vein ;
and (f/) the internal maxillary vein, a large vessel, which requires more par-
ticular description.

The internal maxillary vein corresponds somewhat in direction
and position with the artery of the same name, and receives branches
from the neighbouring parts, most of which are the ven comites of
the corresponding divisions of the internal maxillary artery. Thus
three or four deep temporal branches descend from the temporal muscle ;
others come from the pterygoid, masseter, and buccinator muscles.
The middle meningeal veins and some palatine veins also end in the
internal maxillary ; and lastly, branches from the surface of the upper
jaw—supertor dental, and another, of large size, from the lower jaw,
emerging from the dental foramen—inferior dental. 'These different
branches form a plexus of veins, named pterygoid plexus, which is placed
in the lower part of the temporal fossa, between the temporal and the
external pterygoid muscle, and in part between the pterygoid muscles.
It communicates in front with the facial vein, and above, with the
cavernous sinus by branches through the base of the skull. From this
plexus proceed one or two short trunks, which join nearly at right
angles with the temporal vein.

The facial communicating vein, extending between the temporal vein at the
angle of the jaw and the facial vein, a little in front of it, is a short trunk,
usually the larger of the two into which the temporal vein divides, and placed
nearly transversely, so as to allow the flow of blood either from the temporal
into the internal jugular vein, or from the facial into the external jugular.

External Jugular Vein.—This vein commences on a level with
the angle of the lower maxilla, at the end of the temporal vein, and
descends perpendicularly between the platysma and fascia, crossing the
sterno-mastoid muscle. In consequence of the oblique direction of that
muscle, the vein gets to its outer border, and continues behind it down
to the lower part of the neck, where it pierces the fascia to terminate
either as a single trunk, or by two or three branches in the subclavian
vein. It is provided with a valve at its lower end, and in most cases
with another about the middle of its course.

Tributaries.—The external jugular vein receives some large branches from
behind, and superficial branches from the fore part of the neck. The largest
branches are the following.

(a) The posterior branch, lying at first between the splenius and trapezius
muscles, passes down at the outside of the jugular vein, and below the middle of
the neck opens into that vessel.

(>) The suprascapular and posterior scapular veins, corresponding to the
arteries of the same name, pass transversely inwards to join the external jugular
vein close to its termination.

AFB 4 VEINS OF THE HEAD AND NECK,

Fig, 304.

Fig. 804.—Dracrammatic View or THE SinusEs or THE Dura MATER AND SOME OF THT

mee, VEINS or THE Neck and Hzap (modified from Cloquet and other sources).
(A. T.) 3

The greater part of the calvarium has been removed ; but an arched strip has been
kept in the fore and upper part of the region of the superior longitudinal sinus. The
occiput has been entirely removed so as to expose the lateral sinus and its termination in
the jugular vein. a, the falx cerebri ; b, 2’, the tentorium cerebelli ; e, zygomatic arch; d,
malar bone ; ¢, angle of the jaw ; f, spinous process of the axis vertebra ; 1, superior
longitudinal sinus ; 2, inferior longitudinal sinus ; 2, 3, straight sinus ; 2’, internal veins
of the brain (veins of Galen) ; 3, lateral sinus, descending to 4, the commencement of
the internal jugular vein ; 3’, superior petrosal sinus ; 4, 4, the internal jugular vein ; 5, 5,
superficial temporal vein, leading into the external jugular vein ; 6, middle temporal ;
7, posterior auricular ; 8, internal maxillary ; 8’, pterygoid plexus and communications
with the deep temporal veins ; 9, communicating branch between the facial, temporal,
and external jugular; 9, pharyngeal branches ; 10, facial vein ; 10’, submental
branch ; 10", continuation of the facial into the angular ; 11, an occasional branch from
the neck ; 12, vertebral vein and artery ; 13, external spinal veins forming a plexus over
the vertebral arches ; 14, occipital sinus communicating above the atlas with the spinal
plexus.

THE INTERNAL JUGULAR VEINS. A479

The anterior jugular vein arises from the convergence of some
superficial branches in the submaxillary region. ‘This vessel lies along
the fore part of the neck, sometimes near the sterno-mastoid muscle,
and either terminates by inclining outwards to join the external jugular
vein, or, after giving to it a branch of communication, sinks beneath
the sterno-mastoid muscle, and ends in the subclavian vein. The
lower ends of the two anterior jugular veins are frequently united by
a transverse branch placed behind the sterno-mastoid muscles and top
of the sternum.

Varieties.—The external jugular vein is very variable in size. It is frequently
very small, and may be absent altogether. It is sometimes joined by the cephalic
vein of the arm, or by a jugulo-cephalic branch of that vein running up over
the clavicle. The external jugular vein has also been seen to descend in front of
the clavicle, and pass through the infra-clavicular fossa, to join the subclavian
vein beneath the clavicle. The anterior jugular vein is likewise very variable.

Internal Jugular Veins.—These veins, receiving the blood from
the brain and cranial cavity, are continuous at their upper extremities
with the lateral sinuses within the cranium, and terminate inferiorly
in the innominate or brachio-cephalic veins. The commencement of
each internal jugular vein at the wide part (jugular fossa) of the
foramen jugulare, is somewhat enlarged, and has been named the sinus
or gulf of the internal jugular vein. Beneath the skull, the vein is
supported by the rectus lateralis muscle, and lies close to the outer side
of the internal carotid artery, as far as the cornu of the os hyoides.
It is joined at this point by. the common facial vein, and becomes
considerably enlarged; it then descends parallel with the common
carotid artery, lying at its outer side and enclosed in the same sheath,
together with the vagus nerve. At the root of the neck it joins
nearly at a right angle with the subclavian vein, and so forms the
innominate or brachio-cephalic vein. Close to the lower termination
of the jugular, or from half an inch to an inch above it, is placed a
double valve as in other veins. (Struthers, “ Anat. and Phys.
Observ.,” p. 175.)

Tributaries.—Previously to to its junction with the facial vein, the internal
jugular receives the lingual, pharyngeal, and occipital veins; one or more of
which, however, very frequently end in the common facial trunk.

(a) the lingual vein begins at the side and upper surface of the tongue, and
passes backwards, receiving branches from the sublingual gland ; occasionally
the ranine vein joins it, and sometimes also the pharyngeal.

(b) The pharyngeal vein commences at the back and sides of the pharynx, and
sometimes ends in the superior thyroid vein, and at other times in the lingual,
or separately in the internal jugular vein.

(c) The occipital vein, corresponding in course and distribution with the
occipital artery, communicates with a plexus of veins upon the occiput, and
terminates occasionally in the external jugular vein, but more frequently in the
internal.

(d) The common facial vein has been already described.

(ce) The laryngeal vein receives branches from the larynx through the thyro-
hyoid membrane, and opens into the internal jugular, the common facial, or
sometimes into the superior thyroid vein.

(f) The superior thyroid vein commences by branches in the thyroid body,
in company with those of the superior thyroid artery, and runs transversely
outwards.

480 VEINS OF THE HEAD AND NECK.

(y) The middle thyroid vein, likewise derived from the thyroid hody, is placed
lower than the superior thyroid.

VENOUS CIRCULATION WITHIN THE CRANIUM.

The part of the venous system contained within the skull consists of
veins properly so called, and of certain channels called sinuses, which
receive the blood from those veins, and conduct it to the internal
jugular veins. The sinuses alluded to are spaces left between the
layers of the dura mater, the fibrous covering of the brain.

CEREBRAL VEINS.

The veins of the brain are divisible into those which ramify upon its
surface, and those which are placed within its ventricles.

Fig. 305.—InTERNAL View oF THE BASE oF THE SKULL, SHOWING THE SINUSES OF THE
Dura Marsr, &. (A. T.) 4

The sinuses of the dura mater have been opened, a small portion of the roof of the
orbit has been removed posteriorly on the left side, and the dura mater has been dissected
so as to bring into view the arteries at the base of the skull, the venous sinuses and the
trunks of the cranial nerves.

I., the olfactory bulb ; II., the optic nerves ; III., placed on the pituitary body,
indicates the third nerve ; IV., the trochlear nerve; V., placed opposite to the middle
of the three divisions of the fifth nerve; VI., the sixth nerve; VII., the facial and
auditory nerves ; VIII., placed opposite to the three portions of the eighth pair ; IX., the

CEREBRAL VEINS. 481 .

hypoglossal nerve ; 1, the right internal carotid artery as it makes its turn in the cavern-
ous sinus in the groove of the sphenoid bone ; 2, its epthalmie branch proceeding into
the orbit, below and to the outside of the optic nerve ; 3, division of the basilar artery
into the two posterior cerebral arteries, one of which is represented on the right side as
giving off the communicating artery to the internal carotid ; 4, basilar artery ; 5, verte-
bral arteries giving off the anterior spinal ; x, great meningeal vessels spreading upwards
from the foramen spinosum ; 6, superior petrosal sinus ; 7, inferior petrosal running
back into the lower part of the lateral sinus ; 8, termination of the lateral sinus in the
internal jugular vein, and continuation of the lateral sinus ; 8’, commencement of the
lateral sinus; 9, occipital sinuses ; 10, torcular Herophili, and below that number in
the figure, the superior longitudinal sinus.

The superficial veins upon the upper surface of the hemispheres
are for the most part lodged in the tortuous sulci between the convo-
lutions ; but some run over the convexity of the convolutions. ‘Their
general direction is towards the middle line; and on reaching the
margin of the longitudinal fissure between the hemispheres, they
receive branches from the flat mesial surface of the hemispheres, and
becoming invested by tubular sheaths of arachnoid membrane, incline
obliquely forwards and open in that direction into the superior longi-
tudinal sinus.

The veins upon the sides and under surface of the brain are directed
outwards, to open into the lateral and other sinuses at each side.

The deep veins of the brain commence by branches within the
ventricles of that organ. Thus, upon the surface of the corpus
striatum several small venous branches are seen, which for the most
part converge to form a slender vein which runs along the groove
between the corpus striatum and optic thalamus, and opens into one
of the veins of the choroid plexus. The minute veims of the choroid
plexus pass backwards, and incline towards the middle line from each
side, so as to form, by their union, two veins—vene Galent. These,
lying parallel, run directly backwards, enclosed within the velum inter-
positum, and escape from the interior by passing through the great
transverse fissure of the brain between the under surface of the corpus
callosum and the corpora quadrigemina. In this way they reach
the anterior margin of the tentorium cerebelli, at its place of union
with the falx cerebri, where they terminate by entering the straight
sinus.

The veins of the cerebellum are disposed in two sets. Those of the
upper surface incline inwards and forwards for the most part, and run
upon the upper vermiform process, over which they ascend a little to
reach the straight smus, in which they terminate; some, farther for-
ward, open into the veins of Galen. Those at the under surface run
transversely outwards, and pour their contents into the occipital and
the lateral sinuses.

CRANIAL SINUSES.

The venous sinuses within the cranial cavity admit of being
divided into two sets, viz., those placed in the prominent folds of the
dura mater, and those situated in the base of the skull.

The form and size of the sinuses are various. All of them are lined
by a continuation of the internal membrane of the veins, the dura
mater serving as a substitute for the other coats.

The sinuses which are contained in the seyeral processes or folds of

VOL, I. Moat

s

482 VEINS OF THE HEAD AND NECK.

the dura mater converge to a common point, which corresponds with
the internal occipital protuberance, and is called the confiuence of
the sinuses or torcular Herophili. The form of the torcular is very
irregular. Five or six apertures open into it: viz., one from the longi-
tudinal, and one from the straight sinus; two from the right and left
lateral sinuses ; and one or two from the posterior occipital sinuses.

Fig. 306. Fig. 306.—SkercH or tHe Iy-
TERNAL VEINS OF THE CRANIUM
AND Noszr. +}

a, torcular Herophili; 8, su-
perior longitudinal sinus of the
dura mater ; c, inferior longitudinal
sinus ; d, straight sinus; e, in-
ternal veins of the brain, or veins
of Galen; g, occipital sinus; h,
superior petrosal sinus ; 2, inferior
petrosal sinus ; 4, nasal veins on the
septum ; some of which superiorly
form the commencement of the
superior longitudinal sinus, and
others lower down pass out by the
spheno-palatine foramen.

The superior longitu-
dinal sinus (s. falciformis
superior), commencing at the crista galli, extends from before backwards,
in the upper border of the falx cerebri, gradually increasing in size as
it proceeds. It is three-sided, and is crossed obliquely at the inferior
angle by several bands, the chorde Willis. ‘The veins from the cerebral
surface open into this sinus chiefly towards the back part ; and in such
a way that the apertures of the greater number of them are directed
‘rom behind forwards, contrary to the direction of the current within
it. The longitudinal sinus communicates with the veins on the out-
side of the occipital bone, by a branch (one of the “ emissary veins,”
Santorini) which passes through a hole in the parietal bone.

The inferior longitudinal sinus (s. falciformis inferior) is very
small, and has so much of a cylindrical form, that it is sometimes
named wferior longitudinal vein. Placed in the inferior concave border
of the falx cerebri, it runs from before backwards, and opens into the
straight sinus on reaching the anterior margin of the tentorium cere-
belli. It receives branches from the surface of the falx cerebri, and
sometimes from the flat surface of the hemispheres.

The straight sinus (s. tentorii) rans backwards in the base of the
falx cerebri, gradually widening as it approaches the torcular
Herophili, in which it terminates. Besides the inferior longitudinal
sinus, the vense Galeni and the superior veins of the cerebellum open
into it.

The lateral sinuses (s. transversi) are of considerable size. Their
direction conforms to that of the groove marked along the inner sur-
face of the occipital and other bones, and extending from opposite the
internal occipital protuberance to the foramen jugulare. The sinus of
the right side is usually larger than that of the left ; both commence at
the torcular Herophili, and terminate in the jugular veins. The lateral
sinuses receive the blood transmitted from both the longitudinal sinuses,

LOWER SINUSES OF THE DURA MATER. 483

from the straight and occipital sinuses, from the veins upon the sides
and base of the brain, from those on the under surface of the cere-
bellum, and from some of the veins of the diploé, The petrosal sinuses
also join the lateral sinus on each side : and two emissary veins connect
these with the veins at the back of the head and neck.

Fig. 807.—SketcH oF THE VENous SINUSES
IN THE Bask GF THE CRANIUM, WITH THE
OPHTHALMIC VEIN.

a, sella turcica and circular sinus; 6,
cavernous sinus receiving c, the ophthalmic
vein ; d, superior petrosal; ce, inferior petrosal
sinus ; f, transverse sinus ; g, occipital ; h,
lateral ; 2, termination of the superior longi-
tudinal in the torcular Herophili.

The posterior occipital sinus is
sometimes a single canal, at other
times double, as if composed of
two compartments. It lies along
the attached border of the falx
cerebelli, extending from the pos-
terior margin of the foramen magnum
to the confluence of the sinuses.
It communicates in front with the
posterior spinal plexuses of veins.

The sinuses placed at the base of
the skull are as follows, taking them in their order from before backwards.

The circular sinus has the form of a ring, and is placed super-
ficially in the substance of the dura mater round the pituitary body ; it
receives the blood from the minute veins of the pituitary body and
communicates at each side with the cavernous sinus. Sometimes it is
only partially developed, the part in front of the gland being that
usually present ; sometimes, however, it is behind the gland.

The cavernous sinuses, placed one on each side of the body of the
sphenoid bone, over the roots of the great wings, and stretching from
the sphenoidal fissure to the apex of the petrous portion of the tem-
poral bones, are of considerable size, and of very irregular form. Each
receives the ophthalmic vein at its fore part, and communicates in-
ternally with the circular sinus, and posteriorly with the petrosal
sinuses. In the wall of each, separated by the lining membrane from
the cavity of the sinus, pass forward the third, fourth, and sixth
cranial nerves, the ophthalmic division of the fifth nerve, and the
internal carotid artery.

The superior petrosal sinus is a narrow canal running along the
upper margin of the petrous part of the temporal bone. Commencing
at the back part of the cavernous sinus, it is directed outwards and
backwards in the attached margin of the tentorium cerebelli ; and,
descending a little, ends in the lateral sinus where this lies upon the
temporal bone.

The inferior petrosal sinus, wider than the upper, passes downwards
and backwards along the lower margin of the petrous bone, between
this and the basilar process of the occipital bone. It opens into the

lateral sinus near its termination, or into the internal jugular vein.
Ir2

s

484 VEINS OF THE HEAD AND NECK.

The anterior occipital or transverse sinus (sinus basilaris) is
placed at the fore part of the basilar process of the occipital bone, so as
to establish a transverse communication between the two inferior
petrosal sinuses.

OPHTHALMIC VEIN.

The ophthalmic vein opens into the cavernous sinus. Its branches
are distributed in the different structures contained within the orbit, in
company with the branches of the ophthalmic artery : some small rami-
fications arise from the eyelids, whilst others communicate with the
angular branch of the facial vein ; and those which accompany the
supraorbital artery have similar connections with the veins upon
the forehead. All these branches, together with others arising
from the lachrymal gland, from the different muscles, from the eth-
moidal eclls, and from the globe of the eye, severally named

Fig. 308.

Fig. 308.—Sxetcn or raz OputTHanmic VEIN, AND oF ITs DistrrBpuTion AND CoM-
MUNICATION WITH OTHER Vers (altered from Hirschfeld and Leveillé. A. T.)

The orbit is opened from the outer side and the dissection is similar to that for dis-
playing the ophthalmic artery (Fig. 253, p. 876) ; a, the optic nerve before it enters the
optic foramen ; 6, the superior oblique muscle divided a little way behind its pulley ;
¢, the lachrymal gland lying upon the eyeball; d, the insertion of the inferior oblique
muscle ; 6 foramen rotundum ; f, sinus maxillaris, opened externally : I, the ophthalmic
vein joining the cavernous sinus ; 1, supraorbital branch; 2, muscular and lachrymal
branches ; 3, ciliary ; 4, anterior and posterior nasal or ethmoid ; 5, frontal ; 6, infra-
orbital ; II, facial vein ; 7, communication with the internal maxillary; 8, external
nasal 39, angular, communicating at 10, with the frontal and supraorbital ; III, ex-
ternal jugular vein commencing at the junction of IV, the temporal, and V, the internal
maxillary veins ; 11, meningeal branch ; 12, inferior dental; 13, muscular ; 14, com-
munication between the facial, malar and infraorbital ; 15, placed in the spheno-maxillary
fossa above branches connected with the pterygoid plexus,

VEINS OF THE DIPLOE. 485

according to the arterial branches which they accompany, join to form
a short single trunk, which leaves the orbit by the inner part of the
sphenoidal fissure, where it is placed between the heads of the external
rectus muscle, and terminates in the cavernous sinus.

Varieties.—Not unfrequently one of the frontal veins is much larger than
the others, and descending vertically near the middle of the forehead, joins the
facial and a branch of the ophthalmic vein on one side of the root of the nose.

VEINS OF THE DIPLOE.

The veins of the diploé of the cranial bones are only to be seen
after the pericranium is detached, and the external table of the skull
carefully removed by means of a file. Lodged in canals hollowed in
the substance of the bones, their branches form an irregular network,
from which a few larger vessels issue. These are directed downwards
at different parts of the cranium, and terminate, partly in the veins on
the outer surface of the bones, and partly in the sinuses at the base of
the skull.

Fig. 309.—VerIns oF Fig. 309.
THE DiIpLoE OF THE
CrantA Bonss (after
Breschet). 4

The external table has
been removed from the
greater part of the cal-
varium so as to expose
the diploé and the veins
which have been in-
jected. 1, a single
frontal vein ; 2, 3, the
anterior temporal vein
of the right side; 4,
the posterior temporal ;
5, the occipital vein of
the diploé.

According to Bres-
chet there are four
such veins on each
half of the cranium,
viz., a frontal, an occipital, and two temporal.

The frontal is small, and issues by an aperture at the supra-orbital notch to
join the vein in that situation. There is often only one frontal vein present.

The temporal are distinguished as anterior and posterior. The anterior is con-
tained chiefly in the frontal bone, but may extend also into the parietal, and opens
into the temporal vein, after escaping by an aperture in the great wing of the
sphenoid. The posterior ramifies in the parietal bone, and passes through an
aperture at the lower and hinder angle of that bone to the lateral sinus.

The occipital is the largest of all; and leaves the occipital bone opposite the
inferior curved line to open, either internally or externally, into the occipital
sinus or the occipital vein. Its ramifications are confined especially to the occi-
pital bone.

VEINS OF THE UPPER LIMB.

The veins of the upper limb are divisible into two sets, the super-
ficial, and the deep-seated. Both sets are provided with valves, and

7

406 VEINS OF THE HEAD AND NECK.

these are more numerous in the deep than in the subcutaneous veins.
Valves are constantly to be found at the entrance of branches in the
main vessels.

SUPERFICIAL VEINS OF THE UPPER LIMB.

The superficial veins of the upper limb are much larger than the
deep ; they lie between the skin and the fascia. At the upper part of

Fig. 310. Fig. 310.—Sxetcu or THE SuperriciAL VEINS oF THE ARM
AND FoREARM FROM BEFORE. 4}

1, biceps muscle; @, radial veins; 0b, cephalic vein; c,
ulnar veins ; d, some of the posterior ulnar veins; ¢, basilic
vein dipping below the fascia ; f, median vein; g, median
basilic ; 2, median cephalic.

«
the forearm they are most frequently collected
into three trunks, the radial, ulnar, and median
veins. At the bend of the elbow the median vein
divides into an outer and an inner vessel, named
respectively median cephalic and median basilic, one
of which joins with the radial to form the cephalic
vein, while the other joins with the ulnar to form
the basic. The two principal cutaneous veins of
the forearm, the radial and the ulnar, commence on
the dorsal surface of the hand, by a sort of plexus,
formed by the convergence of numerous small
veins, which proceed from the dorsal surfaces of the
fingers.

The radial cutaneous vein commences by
branches upon the dorsal surface of the thumb
and fore finger. These ascend over the outer border
of the wrist, and form by their union a large vessel,
which passes along the radial border of the fore-
arm, receiving numerous branches from the anterior
and posterior surfaces. At the bend of the arm, in
the groove external to the biceps muscle, it unites
with the median-cephalic division of the median
vein, to form the cephalic vein.

The cephalic vein ascends along the outer
border of the biceps muscle in the interval
between the great pectoral and deltoid muscles,
and finally, dipping in between those muscles, terminates in the axillary
vein, between the coracoid process and the clavicle.

The ulnar cutaneous veins are two in number, one on the front, the
other on the back part of the forearm. The posterior ulnar cutaneous
vein, begins on the back of the hand by branches, which unite to
form a vein placed over the fourth metacarpal space, and called by some
of the older anatomists “vena salvatella.” This proceeds along the
ulnar border of the forearm on the posterior aspect, and, below the
bend of the elbow, turns forwards to join the anéerior ulnar cutaneous
vein, which ascends from the anterior surface of the wrist. At the
bend of the elbow, the common ulnar cutaneous unites with the median
basilic division of the median to form the basilic vein.

CUTANEOUS VEINS OF THE ARM. 487

The basilic vein, usually of considerable size, ascending along the
inner border of the biceps muscle, in front of the brachial artery, passes
through the fascia below the middle of the arm, and finally unites with
one of the venze comites of that vessel, or with the axillary vein, which
it chiefly forms.

Fig. 311.—View or tHe SuperricraL VEINS AT
THE BEND oF THE Arm (from R, Quain). 4

The full description of this figure will be found
at p. 400. The following numbers indicate the
veins:—At 1 and 2, the fascia is opened in front
of the brachial artery and its accompanying
veins ; the inner vena comes, marked 1, has
been divided, the outer marked 2, is entire;
+, the median nerve; 2, the basilic vein; 3’, the
ulnar veins ; 4, the cephalic vein; 4’, one of the
radial veins; 5, the median vein: 5 to 4’, median
cephalic; 5 to 3’, median basilic,

The median cutaneous vein results
from the union, on the anterior part of
the forearm, of several branches. Itisa
short trunk of variable length, which
ascends between the ulnar and radial
cutaneous veins on the front of the
forearm, and terminates beneath the
hollow in front of the elbow by dividing .
into the median basilic and median
cephalic branches, which diverge up-
wards from each other. Close to its
bifurcation it receives a short branch,
the deep median vein, which pierces the
fascia to meet it, and forms a communi-
cation between it and the deep veins
accompanying the arteries.

The median basilic vein, inclining inwards to join the basilic vein,
passes in front of the brachial artery, from which it is separated by
the fibrous expansion given by the tendon of the biceps muscle to the
fascia covering the flexor muscles; it is crossed by branches of the
internal cutaneous nerve.

The median cephalic vein, directed outwards, unites with the
cephalic vein. Branches of the external cutaneous nerve descend be-
hind it.

Varieties.—The cephalic vein frequently terminates in the external jugular
instead of the axillary vein ; usually running up over the clavicle, but sometimes
below that bone. In one case it passed below the clavicle but sent a branch
over, which also opened into the external jugular, and thus formed a venous
ring round the clavicle (Nuhn). In other cases the cephalic is merely united to
the external jugular by a communicating branch (jugulo-cephalic) which rurs
up over the clavicle. In two cases which occurred in the dissecting-room ot
Glaszow University, winter, 1872-73, this jugulo-cephalic branch instead of pass-
ing over the clavicle passed right through the bone, accompanied in one of the
cases by a small artery.

DEEP VEINS OF THE UPPER LIMB.
The brachial artery and its various branches in the arm, forearm,

s

488 THE AXILLARY VEIN.

and hand, are each accompanied by two veins, named venz comites.
These companion veins lie one on each side of the corresponding artery,
and are connected with each other at intervals by short cross branches,
which in some places closely surround the artery. Their distribution so
nearly corresponds with that of the arteries, that they need not be more
particulary described.

The brachial veins, or companion veins of the brachial artery,
terminate at the lower margin of the subscapularis muscle by joining
‘the axillary vein ; not unfrequently, however, one of them will be found
to come forward and unite with the basilic, which soon after becomes
continuous with the axillary vein.

Between the several veins of the upper limb numerous communica-
tions exist in their whole course. Thus, those which lie beneath the
integument are connected to each other by branches in the hand and
forearm. Not only are the veins in each pair of vene comites united
by short transverse vessels crossing the artery which they accompany,
but also those attending different arteries have frequent connections
with each other. Lastly, the subcutaneous and the deep veins commu-
nicate freely, especially in the neighbourhood of joints. This general
anastomosis ensures the continuance of the circulation during muscular
action in the frequent and varied motions of the limb.

AXILLARY VEIN.

The axillary vein collects all the blood returning from the upper
limb : its size is very considerable, and it is the highest of the veins of the

Fig 312.

hig. 212.—Vinw or tHE Broop-vrssers or THE RiaHt AXILLA AND ARM FROM THE
INNER SIDE (from R, Quain). +
The detailed description of this figure will be found at p. 399. The following

numbers indicate the principal veins :—2, the axillary vein ; 3, basilic vein ; 3’, median
basilic ; 4, 4’, cephalic vein joining the acromial thoracic and axillary ; 6, alar-thoracie
and subscapular ; 7, one of the brachial veins.

THE SUBCLAVIAN VEIN. 489

upper limb in which valves are constantly found. It extends, like the
corresponding artery, from the lower border of the axilla to the outer
margin of the first rib; it is covered by the pectoral muscles and the
costo-coracoid membrane, and is placed to the inner side of the axillary
artery. It is continuous below with the basilic vein of the arm, either
alone or in conjunction with one of the deep brachial veins.

Tributaries.—The axillary vein receives the subcutaneous veins of the arm,
viz. the basilic at its commencement, the cephalic towards its termination; and
between these the companion veins of the brachial artery; it is also joined by
the several veins corresponding with the branches of the axillary artery, viz.,
the two circumflex and the subscapular veins from the shoulder, the alar vein
from the axilla, and the inferior, superior, and acromio-thoracic veins from the
side of the chest.

SUBCLAVIAN VEIN.

The subclavian vein is the continuation of the axillary, but is not
like it constantly provided with valves, although a pair may often be
found near its termination (Struthers, loc. cit.). It extends from the
outer margin of the first rib to the inner end of the clavicle, behind
which it terminates by joining with the internal jugular vein to form
the innominate or brachio-cephalic vein. The subclavian vein crosses
over the first rib and behind the clavicle, not reaching so high up in
the neck as the subclavian artery; it is covered by the clavicle, and by
the subclavius and sterno-mastoid muscles, and lies on a plane anterior
to the artery, from which, while resting on the rib, it is separated by
the scalenus anticus muscle and the phrenic nerve.

Tributaries.—(a@) The external and anterior jugular veins open into the sub-
clavian vein on the outer side of the scalenus anticus muscle.

(b) The vertebral vein, commencing in branches which proceed from the peri-
cranium and the deep muscles lying behind the foramen magnum of the occipital
bone, passes outwards and downwards to reach the foramen in the transverse pro-
cess of the atlas. Through this foramen, and through the canal formed by the
corresponding foramina of the other cervical vertebra, the vein descends with the
vertebral artery. Emerging at the foramen in the sixth vertebra, it runs forwards
and downwards to join the subclavian vein close to its termination : a small
branch sometimes descends through the foramen in the seventh vertebra, and
opens separately into the subclavian. The vertebral vein is joined in its course
by several branches from the neighbouring muscles: also, immediately before
its termination, by a branch corresponding with the deep cervical artery; and in
the same situation by another branch of considerable size, which descends in
front of the bodies and transverse processes of the vertebre of the neck, and
may be termed the external vertebral vein. It communicates frequently with
the spinal veins in the neck, both those on the outer side, and those in the
interior of the spinal canal. =

Varieties.—The subclavian vein has been seen to pass behind the scalenus
anticus muscle along with the artery (Henle). Im another case the vein and
artery changed places with relation to the muscle. The vein has been seen
several times to pass between the subclavius muscle and the clavicle (Luschka).
Instead of being the continuation of a single axillary vein, the subclavian vein
is sometimes made up by the union of two brachial veins (Henle); or it may
receive as unusual branches a bronchial vein (Weber), or a superficialis colli
inferior vein (Hyrtl).

AZYGOS VEINS.

The azygos veins are longitudinal vessels formed by the union of
the veins corresponding to the arteries of the intercostal spaces, and

7

490 THE AZYGOS VEINS.

are placed on the sides of the spine. Inthe lower part of the thorax

Fig. 313.—Sketcu oF THE Prinorpan Systemic
Venous Trunks, THE Azycos, AnD INTERCOSTAL
VEINS.

For the detailed description of this figure see
p. 473. The following indications relate to the
accompanying part of the text:—8’, the left superior
intercostal veins (the number is omitted on the
right side) ; 9, the main trunk of the azygos vein ; the
uppermost number marks its junction with the supe-
rior cava, the lowest its passage into the abdomen ; 9’,
the left or hemiazygos ; 10, thoracic duct ; 11, inferior
vena cava; 12, the union of a branch of the left
azygos with the left renal vein ; 13, 13’, the right and
left azygos veins continued down into the abdomen,
and joining some of the lumbar veins; 15, union of
lumbar, ilio-lumbar, and sacral veins.

the two veins of opposite sides are dis
posed symmetrically, but higher up the
blood gathered from some of the veins of
the left side is poured into the trunk on
the right, which becomes enlarged and
unsymmetrical, and has on that account
received the name of main or right azygos,
while the united lower veins from the
corresponding parts on the left side con-
stitute the small or left azygos.

The right azygos vein (vena azygos
major) generally commences below by
branches from the lumbar veins (ascend-
ing lumbar) of the right side, and some-
times from the renal vein ; but not un-
frequently it receives a small branch from
the inferior cava, where that vessel turns
forwards to reach its opening in the dia-
phragm. Passing from the abdomen into
the thorax through the aortic opening in
the diaphragm, or to the outer side of
that opening through the fibres of the
right crus, the azygos vein ascends on the
bodies of the dorsal vertebree, until it
arrives opposite the root of the right
lung, over which it arches forwards, and
then opens into the upper vena cava, im-
mediately above the point at which that
vessel is invested by the pericardium.
When passing through the opening in
the diaphragm, this vein is accompanied
by the thoracic duct, both being situated
on the right side of the aorta. In the
thorax, maintaining the same position
with respect to the duct and the ceso-
phagus, it passes in front of the intercostal arteries, and is covered by

THE AZYGOS VEINS. 491

the pleura. It is joined by the several veins which accompany the
aortic intercostal arteries of the right side; and, at about the sixth
or seventh dorsal vertebra, by the left or smaller azygos vein. It is
also joined by several cesophageal and other small veins, and near its
termination by the bronchial vein of the right lung; and it is generally
connected with the right superior intercostal vein. As it communicates
below with the vena cava inferior through one of the branches of that
jarge vein, while it terminates above in the vena cava superior, it forms
a connection between those two vessels. A few valves of imperfect
formation have been found in the azygos vein ; its branches (intercostal
veins) are provided with distinct valves.

On the left side of the chest the veins of the three or four upper
intercostal spaces are usually united into one trunk, forming the left
superior intercostal vein, which (as already mentioned) is most fre-
quently united with the left innominate vein, but sometimes is connected
with the main azygos vein.

Of the remaining left intercostal veins, one or two, generally about
the fifth and sixth, pass directly into the azygos; while the lowest in
greater number unite almost constantly into one trunk, forming the
left or small azygos, which crosses to join the main azygos in the
neighbourhood of the seventh dorsal vertebra. There is frequently
union between these three sets of veins or their intercostal branches,
so that a part of one may be replaced by another, and the relative
size of the veins may be subject to considerable variation.

The left lower or small azygos vein (vena hemiazygos) commences
from one of the lumbar veins (ascending lumbar), or from the left renal
vein, and, having entered the thorax with the aorta, or through the left
crus of the diaphragm, ascends upon the spine in front of the left inter-
costal arteries, receiving the lower intercostal veins of the left side ;
and passing behind the aorta, it opens into the right azygos vein,
opposite the sixth or seventh dorsal vertebra.

Varieties.—The azygos vein has been seen to receive the lower vena cava,
and, in such cases, is of course extremely large. An example of this variety
exists in the Anatomical Museum of Glasgow University. Im one instance,
Meckel found the azygos ending in the subclavian vein.

All the intercostal veins of the left side have been observed in some instances
to join a single vein, which ended in the left innominate; the arrangement cor
responding with that on the right side of the body.

The bronchial veins return the blood employed in the nutrition of
the lungs. Their course corresponds with that of the bronchi, which
support them as they pass towards the root of the lungs. The bron-
chial vein of the right side opens into the trunk of the azygos vein
near its termination, that of the opposite side ends in the superior
intercostal vein.

VEINS OF THE SPINE.

The spinal veins form plexuses of closely anastomosing vessels along
the whole length of the spinal column. They have no valves.

The veins within and upon the spinal column may be distinguished
into the following sets: a. The dorsal, placed deeply in the vertebral
grooves, and resting upon the spines and arches of the vertebrae : 6.
The veins lodged within the bodies of the vertebrae : c. The anterior
longitudinal, two long series of veins, or rather venous plexuses, extend

s

492 THE SPINAL VEINS.

behind the bodies of the vertebree in the whole length of the canal :
7. The posterior longitudinal veins, situated within the canal on the
fore part of the arches of the vertebrae: e. The veins of the spinal
cord. There are likewise branches of communication, some of which
connect all the other sets together, and some which bring them into
connection with the general venous system. (Breschet, ‘ Hssai sur les
Veines du Rachis,” 4to; “Traité Anatomique sur le Systéme Veineux,”
fol., 1829 ; Cloquet, “‘ Traité d’Anatomie descriptive,” &c.)

a.—The dorsal veins. The blood from the muscles and integument
along the back of the spine is returned by a series of short veins, which
ramify upon the arches and spinous processes of the vertebree. They
run forwards close to the spinous processes, and on reaching the in-
terval between the arches of the vertebrae, pierce the ligamenta sub-
flava, and terminate in a venous plexus within the canal. Towards the
outer part of the intervertebral grooves other veins arise, which pass
obliquely forwards, through the intertransverse spaces, in company
with the posterior branches of the lumbar and intercostal arteries, and
open into the veins which accompany those vessels.

Fig. 314, A and B.—Honrizontan anp VERTICAL
Sections oF THE Lower Dorsat VERTEBR,
SHOWING THE ExrrrNAL AND INTERNAL VEINS

OF THE SPINE (after Breschet). 3

a, spinous process; 6, transyerse process; ¢,
body ; d, spinal canal; 1, anterior external veins
of the body; 2, posterior external veins of the
vertebral column communicating with the internal
and forming a plexus over the laminz and pro-
cesses; 3, the posterior, and 4, the anterior in-
ternal plexus of veins of the vertebral canal ; 5,
the internal veins of the body joining the internal
spinal veins; 6, the lateral veins, which are joined
by the internal and external spinal veins, and
themselves unite with the intercostal.

b.—The veins of the bodies of the
vertebree (ven basis vertebrarum,
Dupuytren) are comparatively large
vessels contained in the canals within
the bodies of the vertebre ; the arteries
which accompany them being very small.
They anastomose on the front of the
bones with some of the superficial veins ;
and the trunk of each, having reached
the spinal canal through the foramen
in the posterior surface of the body of
the vertebra, divides into two branches, which diverge and terminate
in the large spinal veins behind the bodies of the vertebre.

c—The anterior longitudinal spinal veins.—The blood collected
by the different vessels here described is poured into two large veins, or
rather tortuous venous canals, which extend, one on each side, along
the whole length of the spinal canal behind the bodies of the vertebrae.
These vessels (the great spinal veins of Breschet) are alternately con-
stricted and enlarged, the constricted points corresponding with the
intervertebral foramina, where they are drawn forwards, and bound

THE SPINAL VEINS. 493

down by the branches of communication which pass outwards. In
some parts the veins are double, or even triple, so as to form a plexus,
and occasionally they are altogether interrupted. In the thoracic
region their communicating branches open into the intercostal veins,
in the loins into the lumbar veins, in the neck for the most part into
the vertebral.

d. The posterior longitudinal spinal veins are a complex interlace-
ment of tortuous veins along the inner or anterior surface of the arches
of the vertebre. In the lower part of the canal this interlacement of
veins is not so close as in the upper portion, where it usually conceals
(if the injection has been successful) the whole surface of the dura
mater. These veins converge to the intervertebral foramina, and join
by rather small vessels with the intercostal veins.

e.—The veins of the spinal cord (Breschet) ramify upon the cord
and its nerves, enclosed within the sheath formed by the dura mater.
Though they communicate with the other spinal veins, they are not
injected with them, even when the injecting process is most successful.
Very small, long, and tortuous, they run upon both surfaces of the cord,
and form a diifused network. They become larger, for the most
part, as they ascend, but near the base of the skull they are smaller
than in the lumbar region. They communicate freely with the spinal
veins and plexuses, by means of branches which accompany the nerves
towards the intervertebral foramina. Near the base of the skull they
unite to form two or three small trunks, which communicate by trans-
verse branches with the vertebral veins, and terminate in the inferior
cerebellar veins, or in the petrosal sinuses.

From a consideration of the connection and arrangement of the
different parts of these complex veins, it would appear that the main
currents of the blood in each part flow through them horizontally.
The dorsal veins pour their blood into the longitudinal plexus on the
inner surface of the arches of the vertebra ; thence it is collected, at
each of the intervertebral foramina, by two or three small converging
branches, which open into some of the veins outside the vertebral
column in front, viz., into the lumbar, azygos, and cervical veins. Into
these, also, the contents of the great spinal veins are conveyed by the
short communicating branches already noticed.

INFERIOR VENA CAVA.

The lower or ascending vena cava returns the blood from the
lower limbs, and from the viscera of the pelvis and abdomen. It
commences at the junction of the two common iliac veins on the side
of the fifth lumbar vertebra, and thence ascends along the right side
of the aorta, as far as the posterior border of the liver; it there
becomes lodged in a groove in that organ, and inclines forwards to
reach the opening in the diaphragm appropriated to it, and after being
enclosed in a fold of the pericardium, terminates in the right auricle
of the heart. A large valve is situated at its entrance into the
auricle, named the valve of Eustachius, which, however, as explained
in the description of the heart, is only a vestige of a foetal structure,
variable in size, and without influence in preventing reflux of the
blood. ‘

TRIBUTARIES.—Besides the common iliac veins, the inferior vena
cava receives the following.

494 THE INFERIOR VENA CAVA.

a.—The middle sacral vein, taking its course upwards on the front
of the sacrum, opens into the left common iliac vein, or into the com-
mencement of the vena cava.

b.—The lumbar veins correspond in number with the arteries of the
same name: they commence by small posterior branches in the muscles
of the back ; and by others from the walls of the abdomen, where they
communicate with the epigastric and other veins in the neighbonr-
hood. Having reached the spine, they receive branches from the
spinal plexuses, and proceed forward upon the bodies of the vertebree,
behind the psoas muscle: those on the left side passing behind the
aorta, terminate in the back of the vena cava. Some of these veins
are frequently found to unite into a single trunk before their termina-
tion. ‘The lumbar veins of the same side communicate with each
other by branches which cross in front of the transverse processes.
Not unfrequently a branch of this description is met with called the
ascending lumbar vein, which connects more or less completely the
common iliac vein, the ilio-lambar and lumbar veins, and the azygos
vein.

c.—The spermatic veins, proceeding upwards from the testicle and
forming part of the constituents of the spermatic cord, enter the
abdomen, and ascend on the psoas muscle behind the peritoneum.
Below the abdominal ring there are numerous convoluted branches
forming the spermatic plexus (plexus pampiniformis). These branches
gradually unite and form a single vessel, which opens on the right side
into the lower vena cava, and on the left into the renal vein. The
spermatic veins sometimes bifurcate before their termination, each
division opening separately; in this case the veins of the right side
may be found communicating with the vena cava and the renal vein.

In the female the ovarian veins have the same general course as the
ovarian arteries ; they form a plexus near the ovary (ovarian or pam-
piniform plexus) in the broad ligament, and communicate with the
uterine plexus.

Valves exist in the spermatic veins in man (Monro) ; and in excep-
tional cases they have been also seen in the ovarian veins (Theile).

d.—The renal or emulgent veins are short but of very considerable
size. That of the left side is longer than that of the right, and passes
in front of the aorta, They join the vena cava at nearly a right angle.
The renal veins usually receive branches from the suprarenal capsules ;
the left has also opening into it the spermatic vein of the same side.
A valve is usually found at the orifice of the left spermatic vein, or in
the renal vein within a quarter of an inch from the orifice of the sper-
matic. (Rivington. Journ. of Anat. Vol. VIL., p. 163.)

e—The capsular or suprarenal veins, though actually small, are,
relatively to the organs from which they arise, of considerable size.
On the right side the vein ends in the vena cava, and on the left in the
renal or phrenic vein.

f—The phrenic veins follow exactly the course of the arteries sup-
plied to the diaphragm by the abdominal aorta.

g—The hepatic veins return from the liver the blood sent to that
organ by the portal vein and hepatic artery. They converge to the
groove in which the inferior vena cava lies, and pass at once obliquely
into that vein. ‘There are usually three sets of hepatic veins pro-
eceding to this common point: those from the right and left lobes are

BRANCHES OF THE INFERIOR VENA CAVA. 495

oblique in their direction, those from the middle of the liver and the
lobule of Spigelius have an intermediate position and course. The
hepatic veins have no valves ; but, owing to their oblique entrance
into the vena cava, a semi-lunar fold is seen at the lower border of the
orifice of each vein.

Varietics.—The lower vena cava presents some occasional deviations from its
ordinary condition, which may be briefly noticed.

In the lower part of its course it is sometimes placed to the left side of the
aorta, and, after receiving the left renal vein, resumes its ordinary position by
crossing over the great artery. Less frequently, the vena cava is placed alto-
gether on the left side, and is continued upwards to the heart, without any
change in its direction ; this occurs in cases of transposition of the thoracic
and abdominal viscera and of the great vessels.

In a more numerous class of cases, the left common iliac vein, instead of
joining the right in its usual position, is connected with it only by a small
branch, and then ascends on the left side of the aorta. After receiving the left
renal vein, it crosses over the aorta, and terminates by uniting with the common
iliac vein of the right side. In these cases, the vena cava inferior can be said
to exist only at the upper part of the abdomen, and below this point there is a
vein on each side of the aorta,

Lastly, the lower vena cava, instead of ending in the right auricle of the heart,
has been seen to join the right azygos vein, which is then very large so that the
blood from the lower, as well as from the upper part of the body, is returned to
the heart through the upper vena cava. In this case, the hepatic veins do not
join the lower cava, but pass directly into the right auricle, at the usual place of
termination of the great vein. (Specimen in Glasgow University Museum.)

The left renal vein has been seen to cross behind the aorta.

In a remarkable case, observed by Rothe, one of the hepatic veins ended, not
in the lower cava, nor in the right auricle, but in the right ventricle of the heart,
its orifice being guarded by valves. (Act. Acad. Joseph. Med. Chir. Vindobonensis,
t. i. p. 233, tab. 5. Vindobone, 1788.)

VEINS OF THE LOWER LIMB AND PELVIS.

The veins of the lower limb are divisible into two sets, those of the
one being deeply seated, those of the other running in the superficial
fascia. All the veins of the lower limb, as high as the femoral venous
trunk, are provided with valves, and these are more numerous than in
the veins of the upper limb. The deep veins have more valves than
the subcutaneous set.

SUPERFICIAL VEINS OF THE LOWER LIMB,

Immediately beneath the integument, on the dorsum of the foot,
there exists a network of veins forming an arch, from which issue two
principal trunks, which are named the internal or long and the external
or short saphenous veins.

The internal or long saphenous vein extends from the ankle to
within an inch and a half of Poupart’s ligament. Taking rise from
the plexus of veins on the dorsum of the foot, it passes upwards in
front of the inner ankle, and along the inner border of the tibia,
accompanied by the internal saphenous nerve. It inclines a little
backwards as it passes the inner condyle of the femur, and ascending
along the inner and fore part of the thigh, it terminates in the femoral
vein, at the saphenous opening in the fascia lata, through which it
passes. ,

In the leg it communicates with the deep veins accompanying the

496

VEINS OF THE LOWER LIMB.

anterior and posterior tibial arteries, and in the thigh one or more
branches pass between it and the femoral vein. ‘This long vein has a
variable number of valves. Sometimes six have been counted; in other

Fig, 315.

cases only four or even two. It contains more
in its course through the thigh than in the lee.

Fig. 315.—Supmrrician Vrrns or THE Front anp Iyyur
Sipz or Tae Lowrr Lins.

1, the saphenous aperture of the fascia lata ; a, super-
ficial epigastric vein ; b, external pudic ; ¢, superficial cir-
cumflex iliac ; d, external or short saphenous beginning on
the dorsum of the foot (see Fig. 516).

Tributaries.—The long saphenous vein is joinéd
in its course by numerous cutaneous vessels. Close to
its termination it receives, besides a considerable
anterior branch, the superficial epigastric, caternal
pudic, and superficial circumflex iliar veins correspond-
ing severally to arterial branches of the same name.

It is also usually joined near its termination by a
posterior branch of considerable size, coming from
the posterior and inner part of the thigh.

The external or short saphenous vein pro-
ceeds from branches, which arise along the
outer side of the dorsum of the foot. It passes
behind the outer ankle, and ascends the leg
along the border of the tendo Achillis and on
the belly of the gastrocnemius muscle, accom-
panied by the external saphenous nerve; run-
ning upwards between the heads of the gastro-
cnemius, it unites with the popliteal vein. Oppo-
site the ankle and along the leg it communicates
with the deep veins: and it receives superficial
accessory veins from the outer part of the foot
and the back of the leg.

Variety.—The short saphenous vein sometimes
issues from the popliteal space, and winding round
the inside of the thigh, opens into the long saphenous
vein.

THE DEEP VEINS OF THE LOWER LIMB.

The deep veins accompany the arteries and
their branches, following exactly their distribu-
tion. Those below the knee, being for the most
part disposed in pairs, and presenting the dis-
position described in the corresponding veins of
the upper limb, are named the venz comites
of the vessels with which they are associated.
The ven comites of the arteries of the leg,
namely, the anterior and posterior tibial
veins (the latter having previously received the
peroneal), unite near the lower border of the

popliteus muscle, and form by their junction the popliteal vein. The
valves of the deep veins of the Jeg are very numerous,—ten or twelve
being sometimes found between the heel and the knee.

THE POPLITEAL VEIN. 497

The popliteal vein, thus formed, receives smaller branches corre-
sponding with the articular and muscular arteries, and the larger
branch named the external saphenous vein. In its course through the
ham, the popliteal vein is placed at first internally to the popliteal
artery, then behind, and lastly to the outer side of it, but always pos-
teriorly and between it and the nerve. Thus situated, it passes up
through the aperture in the adductor magnus, and becomes continuous
with the femoral vein.

Varieties.—The union of the veins which form the popliteal is often farther
up than usual, and the lower part of the artery is accompanied by two veins.
This arrangement in some rare cases extends to the entire length of the artery.

Fig. 317.

Fig. 316.—OvTLINE OF THE PostERIon orn Suort SapHenovus VEIN.

The vein, commencing on the dorsum and outside of the foot, is seen to pass up
behind the outer ankle and to dip beneath the fascia in the popliteal space.

Fig. 317.—ViEw oF THE VEINS OF THE GROIN AND NEIGHBOURING PARTS (from
R. Quain). 4

The full description of this figure will be found at p. 455. The following numbers
indicate the veins :—2, the femoral vein ; 3, the large or internal saphenous vein ; 3,
anterior saphenous ; 4, superficial circumflex veins with twigs to the inguinal glands ;
5, superficial epigastric ; 6, superficial pudic.

The femoral vein extends, like the artery which it accompanies,
through the upper two-thirds of the thigh, and terminates at Poupart’s
ligament in the external iliac vein. Placed at first outside the artery,
it gradually inclines inwards behind it; and on reaching Poupart’s
ligament, lies on the inner side, on the same plane with the artery, and

separated from it only by a slight partition of the membranous sheath,
“OL 1. BE

498 THE ILIAC VEINS.

by which they are both invested. In the lower part of its course, the
vein receives all the branches which accompany the offsets of the chief
artery. In the upper part, the deep femoral vein opens into it, having
first received all-the branches from muscles supplied by the deep femoral
artery. Near its termination the femoral vein is joined by the in-
ternal saphenous vein.

Varieties.—The femoral vein occasionally pursues a course different from
that of the artery along the thigh. Extending upwards from the popliteal space,
the vein in such cases perforates the adductor magnus above the ordinary posi-
tion, and, joining with the deep femoral vein, first approaches the femoral
artery at the groin. The same vein is sometimes double in a small part, or more
rarely in almost its whole length.

EXTERNAL ILIAC VEIN.

The external iliac vein is the continuation of the femoral vein frem
Poupart’s ligament to the junctiou of the internal iliac vein, in the
neighbourhood of the sacro-iliac articulation. It is at first internal to
the artery, and on the left side it continues in that position, but on the
right side it gradually inclines somewhat behind the artery. It does
not possess valves.

Tributaries.—Near its commencement at Poupart’s ligament, the external
iliac vein receives the circumflex iliac and the epigastric veins.

INTERNAL ILIAC VEIN.

The internal iliac vein is formed by the union of branches which
accompany the corresponding branches of the internal iliac artery. The
umbilical vein of the foetus, however, which in the cord accompanies the
corresponding arteries, diverges from these arteries within the body,
and passes upwards to the liver. The internal iliac vein lies behind
the corresponding artery in front of the sacro-iliac articulation, and,
after a short course upwards to the margin of the pelvis, joins with
the external iliac vein to form the common iliac. No valves are
found in the trunk of the internal iliac vein, but they exist in its
branches.

TriIpuTARTES.—The tributaries of the internal iliac vein correspond
in general to the various branches of the internal iliac artery, with the
exception that the internal pudic vein does not receive the main supply
of blood from the dorsal vein of the penis. The visceral veins are
remarkable for their size and frequent anastomoses, and have been
described as forming a series of plexuses, severally named the vesvea/,
prostatic, hemorrhoidal, uterine, and vaginal.

The vesical plexus consists of vessels which ramify over the whole
of the bladder external to its muscular coat, being particularly large and
numerous towards the base of the organ, where they are closely con-
nected with the prostatic and hemorrhoidal plexuses in the male, and
with the vaginal plexus in the female.

The prostatic plexus receives two large vessels, one at each side,
the divisions of the dorsal vein of the penis. These, coursing down-
wards and backwards on the sides of the prostate gland, expand
into a close network at the base of the gland, which is quite encircled
by it.

The hemorrhoidal plexus consists of enlarged and copiously anas-
tomosing veins in the walls of the lower part of the rectum, imme-

BRANCHES OF THE INTERNAL ILIAC VEIN. 499

diatery underneath the mucous membrane. From it proceed superior,
middle, and inferior hemorrhoidal veins accompanying the arteries of
the same name, and it communicates freely with the plexuses in front of
it. The superior hemorrhoidal yein being a branch belonging to the
portal system, the hemorrhoidal plexus forms a very direct communi-
cation between the portal and general venous systems.

Fig. 518.—Internan
VIEW oF THE MALE
PELVIS FROM THE
LEFT SIDE, TO SHOW
THE PRINCIPAL
Veins. (A. T.) 4

The greater part of
the os innominatum
and pelvic wall of the
left side, and the
upper parts of the
rectum and urinary
bladder, have been
removed : the lefi
common iliae and the
vight internal iliac
arteries, and the left
external and internal
iliac veins, have been
cut short. a, the right
psoas magnus muscle ;
6, the anterior su-
perior iliac spine ; ¢,
Poupart’s ligament ;
d, the cavernous and
spongy body of the
penis divided near the
roct ; +, the spongy
body of the bulb,
above which the mem-
branous part of the
urethra, the prostate,
&e. ; e, the left os
pubis close to the
sympuysis ; f, the
anus ; g, the spine of
the ischium with the
short sacro-sciatic ligament; /, auricular sacro-iliac surface ; 7, interior of the urinary
bladder ; 4, exterior of the rectum ; /, transverse process of the fourth lumbar vertebra ;
1, lower part of the vena cava inferior; 1’, abdominal aorta ; 2, common iliac veins ;
2’, right common iliac artery ; 3, external iliac veins ; 3’, external iliac artery ; 4, internal
iliac veins, that of the right side entire, that of the left divided and in great part
removed ; 5, middle and other veins of the sacral plexus; 6, ilio-lumbar and lumbar
veins ; 7, right gluteal and upper lateral sacral veins; 8, 8’, obturator vein and artery
of the right side ; 9, pelvic plexus of veins of the right side; 9’, that of the left side
connected with the lower vesical plexus ; 10, placed on the right side on the short sacro-
sciatic ligament immediately below the division of the internal iliac vein into the pudic
and sciatic veins : on the left side, below 4, the sciatic vein is cut short; 10, lower
down, the pudic vein ; 10’, the perineal veins ; 11, placed on the prostate among the
lower vesical veins, into one of which the left dorsal vein of the penis, 11, is seen to
pass ; 12, placed on the lower part of the rectum, may indicate the plexus of hemorr-
hoidal veins.

The vaginal plexus, surrounding the vagina principally in its
lower part, communicates freely with the hemorrhoidal and vesical
plexuses.

KK 2

500 THE PORTAL SYSTEM OF VEINS.

The uterine plexus pours its blood in greatest part into the ovarian
veins, and is not considerable except in pregnancy.

The dorsal vein of the penis commences by branches which issue
from the glans penis, and form in the first instance two veins, one at
each side of the middle line, in the dorsal groove of the penis. These
receive branches from the spongy body of the penis, and some super-
ficial veins which accompany the external pudic arteries, and proceeding
backwards unite and form a short trunk which enters the pelvis
beneath the subpubic ligament. Here it divides into two branches,
which are directed obliquely downwards over the prostate and the neck
of the bladder, and are united with the prostatic plexus.

COMMON ILIAC VEIN.

The common iliac vein is formed by the confluence of the external
and internal iliac veins. Extending from the sacro-iliac articulation
upwards to near the junction of the fifth with the fourth lumbar ver-
tebra, at a point a little to the right of the middle line, the two common
iliac veins unite to form the lower or ascending vena cava. The right
vein is shorter than the left, and is nearly vertical in its direction. The
right vein is placed behind, and then to the outer side of its artery ;
whilst the left vein is to the inner side of the left common iliac artery,
and then passes behind the right. These veins are destitute of valves.

THE PORTAL SYSTEM OF VHINS.

The portal vein differs from other veins of the body in being sub-
divided into branches at both its extremities. The branches of origin,
by the union of which it may be said to be formed, are the veins of the
chylopoietic viscera, viz., the stomach, intestine, pancreas, and spleen ;
the other branches, or those of distribution, ramifying after the manner
of an artery in the substance of the liver, convey to the capillaries of
that organ the blood collected in the main trunk. This blood, together
with that of the hepatic artery, after having served for the secretion
of the bile and the nourishment of the liver, is withdrawn from that
organ by the hepatic veins, and carried by them into the vena cava
inferior.

The portal vein or vena porte is about three inches in length.
Commencing at the junction of the splenic and superior mesenteric
veins, it passes upwards and a little to the right to reach the transverse
fissure of the liver. It is placed close behind the hepatic artery and the
bile-duct : and is surrounded by the filaments of the hepatic plexus of
nerves, together with numerous lymphatics. All these are imbedded in
loose connective tissue, and enclosed within the layers of the small
omentum. Within the transverse fissure it is somewhat enlarged, and
is there named sinus of the portal vein.

Near the right end of the transverse fissure, the vena porte divides
into two branches. That of the rigit side enters directly the substance
of the corresponding lobe of the liver, and spreads out into branches,
each of which is accompanied by an offset of the hepatic artery and
of the hepatic duct. The /¢ft branch, which is smaller, but necessarily
longer, passes across to gain the left end of the transverse fissure, where
it enters the liver and ramifies like the preceding branch.

—--

BRANCHES OF THE PORTAL VEIN, 501

TrRIBUTARIES.—The principal branches which by their union contri-
bute to form the vena porte are the coronary vein of the stomach, the
superior mesenteric, and the splenic veins. The cystic vein is also
sometimes a lateral tributary of the portal vein, but more frequently
proceeds from its right branch.

Fig. 319.—Vinw oF THE PRIN-
CIPAL BRANCHES OF THE VENA
Portz. 2

1, lower surface of the right
lobe of the liver ; 2, stomach ; 3,
spleen ; 4, pancreas; 5, duodenum ;
6, ascending colon ; 7, small intes-
tines ; 8, descending colon ; a, vena
porte dividing in the transverse
fissure of the liver ; 0, splenic vein ;
c, right gastro-epiploic ; d, inferior
mesenteric ; €, superior mesenteric
vein ; jf, superior mesenteric ar-
tery.

The coronary vein of the
stomach lies parallel with
the artery of the same name.
Its size is inconsiderable,
and its direction transverse
from the cardiac to the py-
loric end of the stomach
along the small curvature.
On reaching the latter point
it turns downwards, and
opens into the trunk of the
vena porte.

The splenic vein, a vessel
of very considerable _ size,
returns the blood not only
from the spleen, but also
from the pancreas, the duo-
denum, the greater part of the stomach and omentum, the descending
colon, and part of the rectum. It commences by five or six branches,
which issue separately from the fissure of the spleen, and soon join to
form a single vessel. It is directed from left to right beneath the
pancreas, in company with the splenic artery, below which it is placed.
On reaching the front of the spine it joins the superior mesenteric
vein, nearly at a right angle. It receives gastric branches (vasa brevia)
from the left extremity of the stomach, the /e/t gastro-eniploic vein, some
pancreatic and duodenal branches, and also the inferior mesenteric vein.

The superior mesenteric vein lies to the right side, and some-
what in front of the artery of the same name. The distribution of its
branches corresponds with that of the superior mesenteric artery, and
it returns the blood from the several parts supplied by that vessel, viz.,
from the small intestine, and from the ascending and transverse parts of
the colon. The trunk, formed by the union of its several branches,
inclines upwards and to the right side, passing in front of the duodenum

—

602 THE PORTAL SYSTEM OF VEINS.

and behind the pancreas, where it joins with the splenic vein to form
the vena porte.

Fig. 520. -—- DiagramMa-
TI¢ OUTLINE OF THE
Portan VEIN AND ITs
RELATION 10 THE LivER,
S07 (A. nS) re
The liver is supposed

to be turned upwards so
as to present a portion of
its under surface. a,
gall-bladder ; 6, square
lobe;. ¢, left lobe; i,
trunk of the vena porte ;
2, great or superior me-
senteric vein ; 2’, its
middle colic branch, form-
ing loops of communica-
tion between the right
and left colic veins ; 3,
intestinal branches; +,
small pancreatico-duode-
nal branch; 4, right
colic branch ; 5, ileo-
colic ; 6, coronary vein of
the stomach ; + +, right
gastro-epiploic ; 7, sple-
nic vein; 7’, its branches
to the spleen; 7", its
branches to the stomach ;
8, inferior mesenteric
vein; 9, left colic branch;
9’, its communication
with the middle colic ;
10, sigmoid ; 11, superior
hemorrhoidal ; 12, the
right, and 13, the left
division of the vena portie
in the transverse fissure
of the liver ; 14, the ob-
literated cord of the um-
bilical vein; 15, the ob-
literated cord of the duc-
tus venosus ; 16, part of
vena cava inferior.

The branches of
the inferior mesen-
teric vein correspond with the ramifications of the artery of the same
name. ‘They commence at the lower part of the rectum in the hemorr-
hoidal plexus, and unite into a single vessel near the sigmoid flexure
of the colon. From this point the vein proceeds upwards and inwards
along the lumbar region, behind the peritoneum, crossing between the
transverse mesocolon and the spine, or farther to the left, and then
passing beneath and behind the pancreas, it reaches the splenic vein
in which it terminates.

Varieties.—In some cases the umbilical vein remains in some degree pervious
from the point where it joins the left portal branch, up to the inner surface of
the rectus muscle, and is joined in the latter situation by a branch of the deep
epigastric vein, thus establishing a communication between the external iliac
and portal veins, This communicating branch, according to Luschka, is normal,

THE CARDIAC VEINS. 503

and is described by him under the name of vena parwmbilicalis, (Champneys,
“ Journ. of Anat.,” vol. vi., p. 416).

VEINS OF THE HEART.

The greater number of the cardiac veins are collected into a large
common trunk which pours its blood into the posterior part of the
right auricle, in the angle between the inferior vena cava and the right
auriculo-ventricular orifice. The terminal part of this vein is consi-
derably dilated, and is named the coronary sinus. The principal
veins leading into it are named the great, the posterior, and the
anterior coronary veins. Among these the first alone deserves the
name of coronary, as it surrounds the heart in the left auriculo-ventri-
cular groove. PR tise:

Besides the larger cardiac veins which join the great coronary sinus,
there are also small separate veins (vence minime cordis), which open
directly into the right auricle, especially along its right border. The
openings of these veins, as well as some depressions which do not admit
veins, have been named foramina Thebesti.

Fig. 321. — View or tHe Apvurr Heart, Fig. 321.
FROM BEHIND, TO SHOW THE Coronary VEINS.
(A. T.) 3

3

a, placed on the back of the right auricle,
points to the Eustachian valve seen within
the opening of the inferior vena cava; 0, the
back of the left auricle; c, the right ventri-
cle; d, left ventricle ; e, vena cava supe-
rior ; f, arch of the aorta; I, sinus of the
great coronary vein ; 2, great coronary vein turn-
ing round the heart ‘in the auriculo-ventricular
groove ; 3, 4, posterior branches ; 5, one of the
small right cardiac veins passing directly into
the right auricle ; 6, the vestige of the left
superior vena cava proceeding over the left
auricle downwards to join the coronary sinus.

The veins of the heart are without
valves excepting at their terminations.

The great cardiac vein (vena cordis
magna) is a vessel of considerable
size, and from the way in which it
coils round the left side of the base
of the heart, or rather of the ven- ;
tricle, it may be named “coronary.” Its chief branch runs along the
groove upon the fore part of the heart, corresponding with the septum
of the ventricles. Commencing at the apex of the heart, it gradually
increases in size as it approaches the base of the ventricles, and then
inclining backwards and to the left side in the groove between the left
auricle and ventricle, ends in the coronary sinus: a valve of two seg-
ments closes its aperture in the sinus. In this course it receives
branches from the ventricles, especially from the left, and also from
the left auricle: and as it passes round the thick margin of the left
ventricle, it receives a vein of some size which ascends to join it.

The posterior cardiac veins ascend on the back of the ventricles,
especially on the left, and open into the coronary sinus by four or more

504 THE ABSORBENT VESSELS.

valved orifices. One of these, larger than the rest, (middle or posterior
cardiac vein), ascends along the groove between the ventricles upon
the posterior surface of the heart. It commences by small branches at
the apex of the heart, which communicate with those of the preceding
vein, and then ascends to the base, receiving branches from the sub-
stance of both ventricles.

The small or anterior cardiac veins (vene cordis parve) are
several small branches, which commence upon the anterior surface of
the right ventricle, and passing upwards and outwards, open separately
into the right auricle, after having crossed over the groove between it
and the ventricle.

The coronary sinus is about an inch in length, and is placed at the
back of the heart in the transverse groove between the left auricle and
ventricle, where it is covered by the muscular fibres of the auricle. At
one end it is joined by a small vein from the right side, and opens into
the right auricle beneath the Thebesian valve ; at the other, it receives
the large coronary vein, and a small straight vein directed obliquely
along the back of the left auricle ; whilst between those points other
veins enter it from the back of the heart. All the veins joining it,
except the small oblique vein, are provided with more or less complete
valves at their terminations.

The coronary sinus, together with the small oblique vein above referred to,
considered with reference to their early foetal condition and certain malforma-
tions to which they are subject along with other neighbouring veins, may be
looked upon rather as the persistent terminal parts of a typically distinct left
superior vena cava, than as simply the main stem of the cardiac veins. The
explanation of this will be found in the description of the development of these

veins,
2—THE ABSORBENT VESSELS.

The absorbent vessels are divisible physiologically into two sets ;—
the lacteals , which convey the chyle from the alimentary canal to the
thoracic duct ; and the /ymphatics, which take up the lymph from all
the other parts of the body, and return it into the venous system.
Anatomically considered, however, the lacteals are not different from
the lymphatics, and may be regarded as the absorbents of the mucous
membrane of the intestine. The larger lacteals and lymphatics are
provided with numerous valves, which give them, when distended, a
somewhat moniliform appearance ; and both are connected in their
course with dacteal or lymphatic glands.

The general anatomy of the absorbents having been elsewhere de-
tailed, only their course and position remain to be here described.
They are gathered into aright and a left trunk, which open into the
angles of union of the subclavian and internal jugular veins. The
large vessel of the left side traversing the thorax is named the thoracic
duct : it receives not only the lymphatics of its own side of the head
and arm, and the most of those of the trunk, but likewise the lymphatics
of both lower limbs, and the whole of the lacteals. The vessel of the
right side is named the right lymphatic duct, and receives the lymphatics
only of that side of the head and neck and upper part of the trunk.

THE THORACIC DUCT.

The thoracic duct is the common trunk which receives the absorbents
from both the lower limbs, from the abdominal viscera (except part of

THE THORACIC DUCT. 505

the upper surface of the liver), and from the walls of the abdomen, from
the left side of the thorax, left lung,
left side of the heart, and left upper
limb, and from the left side of the head
and neck. It is from fifteen to eighteen
inches long in the adult, and extends
usually from the second Inmbar vertebra
to the root of the neck. Its commence-
ment, however, is often as low as the
third lumbar vertebra ; and in some cases
as high as the first lumbar, or even
the last dorsal vertebra. Here there
is usually a dilatation of the duct, of
variable size, which is called recep-
taculum chyli (Pecquet), and is the
common place of junction of the lym-
phatics from the lower limb with the
trunks of the lacteal vessels.

Fig. 322.—Sxetrcu or tHE Tuoractc Doct witu
THE Principat Systemic Veins. (A. T.)

The full description of this figure will be found
at p. 473.

10, 10, indicate the thoracic duct ; the lower
number is close to the receptaculum chyli, the upper
is on the fourth dorsal vertebra, above which the
duct inclines to the left ; 6, on the left subclavian
vein, marks the termination of the duct in the
angle of union of the subclavian and internal jugu-
lar veins ; 5, on the right subclavian vein, indicates
the similar termination of the right lymphatic
trunk.

The lower part of the thoracic duct is
generally wider than the rest, being about
three lines in diameter ; it lies at first
to the right side of or behind the aorta ;
it then ascends on the right side of that
vessel, in contact with the right crus of
the diaphragm, to the thorax, where it is
placed at first upon the front of the dorsal
vertebrae, between the aorta and the azy-
gos vein. The duct ascends, gradually
inclining to the left, and at the same time
diminishing. slightly in size, until it
reaches the third dorsal vertebra, where,
passing behind the arch of the aorta,
it comes into contact with the cesophagus,
lying between the left side of that tube
and the pleura. Continuing its course
into the neck to the level of the upper
border of the seventh cervical vertebra,
it changes its direction and turns for-
wards, at the same time arching downwards and outwards so as to

506 THE ABSORBENT VESSELS.

©

describe a curve over the apex of the pleura, and then terminates on
the outer side of the internal jugular vein, in the angle formed by the
union of that vein with the subclavian. The diminution in the size
of the duct as it ascends is such that at the fifth dorsal vertebra it
is often only two lines in diameter, but above this point it again
enlarges. The duct is generally waving and tortuous in its course,
and is constricted at intervals so as to give it a varicose appearance.

The thoracic duct has numerous double valves at short intervals
throughout its whole course, the constrictions of their attachments
giving a nodulated appearance to the vessel. They are more numerous
im the upper part of the duct. At the termination of the duct in
the veins there is a valve of two segments, so placed as to allow
the contents of the duct freely to pass into the veins, but which
effectually prevents the reflux of either chyle or blood into the
duct.

Varieties.—The thoracic duct is not always a single trunk throughout its
whole extent; it frequently divides opposite the seventh or eighth dorsal ver-
tebra into two trunks, which soon join again ; sometimes it separates for a short
distance into three divisions, which afterwards unite, and enclose between them
spaces or islets. Cruikshank in one case found the duct double in its entire
length ; ‘**in another triple, or nearly so.” In the neck, the thoracic duct often
divides into two or three branches, which in some instances terminate separately
in the great veins, but in other cases unite first into a common trunk. In a case
of right aortic arch the thoracic duct has been observed to end in the veins of
the right side (A. Thomson). Dr. Morrison Watson describes a case in which
without transposition of the viscera, or any change in the disposition of the
branches of the aorta, the thoracic duct terminated in the veins of the right side,
and no trace of a left lymphatic duct could be discovered. (‘‘ Journ. of Anat.,”
vol. vi., p. 427.) In the lower animals, the termination of the thoracic duct in
the veins of the right side as well as of the left is not uncommon.

THE RIGHT LYMPHATIC DUCT.

The right lymphatic duct is a short vessel, about a line or a little
more in diameter, and about a quarter or half an inch in length, which
receives the lymph from the absorbents of the right upper limb, the
right side of the head and neck, the right side of the chest, the right
lung, and the right half of the heart, and from part of the upper surface
of the liver. It enters obliquely into the receding angle formed by the
union of the right subclavian and internal jugular veins, where its
orifice is guarded by a double valve.

LYMPHATICS OF THE LOWER LIMB.

The lymphatics of the lower limb are arranged in a superficial and a
deep series. ‘Those of the superficial series, together with the super-
ficial lymphatics of the lower half of the trunk, converge to the super-
ficial inguinal glands ; with the exception of a few which dip into
the popliteal space. ‘Those of the deep series converge to the deep
inguinal glands.

The popliteal lymphatic glands, usually very small, and four or
five in number, surround the popliteal vessels, and are imbedded in a
quantity of loose fat. They receive from below the deep lymphatics of
the leg, and those which accompany the short saphenous vein ; and

LYMPHATICS OF THE LOWER LIMB. 507

from them proceed efferent vessels,
which ascend with the femoral artery
to the groin.

Fig. 323.—View or THE SupERFIcraL Lyu-
PHATIC VESSELS AND GLANDS OF THE
Lower Lime, AS SEEN FROM THE FRONT
AND InnER Sipe (founded on Mascagni
and others). (A. T.) 2
1, 1, upper inguinal glands receiving the

lower abdominal, the inguinal, penal, and
scrotal lymphatic vessels ; 2, 2, femoral or
lower inguinal] glands, receiving the anterior,
internal, and external femoral lymphatic ves-
sels ; 2’, the internal lymphatic vessels ; 3, 3,
large plexus of lymphatic vessels in thecourse
of the saphenous veins ; 4, the same descend-
ing upon the leg; 5, posterior lymphatics of
the calf of the leg ; 6, lymphatic vessels of
the dorsum of the foot ; 7, those of the heel
and inner ankle.

Thesuperficial inguinal glands
vary much in number, amounting
on an average to eight or ten : they
are divisible into a superior or
oblique and an inferior or vertical
set. The oblique glands lie in the
line of Poupart’s ligament and re-
ceive lymphatics from the integu-
ments of the trunk and genital
organs, together with a few from
the upper and outer part of the
limb: the vertical glands surround
the upper part of the long saphenous
vein, and extend two or three inches
downwards along the course of that
vessel ; they receive the greater
number of the lymphatics which
ascend from the limb. The efferent
vessels of the superficial inguinal
glands perforate the fascia, come
into connection with those situated
deeply, pass into the abdomen by
the side of the blood-vessels, and
being connected with a chain of
lymphatics which le along the ex-
ternal iliac artery, terminate in the
lumbar glands.

The deep-seated inguinal
glands are placed beneath the
others, and surround the femoral
artery and vein.

The superficial lymphatics of
the lower limb arise in two sets,
one from the inner part of the dor-

508 THE ABSORBENT VESSELS.

sum and sole of the foot, the other from the outer. The dnner vessels
follow a similar course to that of the internal saphenous vein: passing
partly in front and partly behind the inner ankle, they ascend along the
inner side of the knee and front of the thigh, and terminate in the
superficial inguinal glands. The owfer vessels, ascending from the outer
side of the foot, pass in great part obliquely across the popliteal space
to join the inner set above the knee; in part they reach the inner
set by crossing in front of the tibia; and a small number of them
accompanying the external saphenous vein, dip down between the
heads of the gastrocnemius muscle, and end in the popliteal glands.
From the middle line of the back of the thigh lymphatics pass round
on both sides to reach the inguinal glands. (Mascagni, “‘ Vasorum
Lymph. Historia,” 1787.)

The deep-seated lymphatics of the lower limb are associated in
their whole course with the deep blood-vessels. In the leg they consist
of three divisions, namely, anterior tibial, posterior tibial and peroneal.
Neither these nor the superficial absorbents pass through any lymphatic
gland in the leg, unless it be those lymphatics which accompany the
anterior tibial artery, near which a small gland is sometimes found
on the front of the interosseous ligament, above the middle of the lee.
The several sets of deep lymphatics in the leg enter the lymphatic glands
situated in the popliteal space. The efferent vessels from those glands
are joined by other lymphatics in contact with the branches of the femoral
artery, and enter the deep inguinal glands. Other deep lymphatics,
derived from the muscles of the gluteal region, ana many proceeding
from the adductor muscles of the thigh, enter the cavity of the pelvis
in company with the gluteal, sciatic, and obturator arteries, and pass
through a series of glands situated in the neighbourhood of the internal
and common iliac arteries.

The superficial lymphatics of the lower half of the trunk con-
verge to the superficial inguinal glands, the direction of some of them
being indicated by the superficial circumflex iliac and epigastric, and
the external pudic arteries. Externally they converge to the groin from
the gluteal region and from the lower part of the back, those from the
back crossing others which pass upwards to the axillary glands. Ante-
riorly they descend from the greater part of the surface of the abdomen,
crossing and mingling above the umbilicus with vessels which ascend
towards the axillary glands.

The superficial lymphatics of the penis usually form three vessels,
two being placed at the sides and the other on the dorsum of the
organ, Commencing in the prepuce and beneath the mucous lining
of the urethra, they pass backwards, unite on the dorsum penis, and,
again subdividing, send branches on each side to the oblique inguinal
glands. The deep-seated lymphatics of the penis pass under the pubic
arch, and end in the glands on the internal iliac artery.

The lymphatics of the scrotum pass to the superficial inguinal
glands along the course of the external pudic arteries.

The lymphatics of the external generative organs in the female
present a disposition similar to that existing in the male.

LYMPHATICS OF THE ABDOMEN AND PELVIS.

The external iliac lymphatic glands, from six to ten or more in

ABDOMINAL LYMPHATIC AND LACTEAL VESSELS. 509

number, clustering round the external iliac artery, receive the efferent
vessels from both deep and superficial inguinal glands.

The internal iliac lymphatic glands, a numerous series placed
on the internal iliac artery, and the sacral glands, placed in the
hollow of the sacrum, receive the lymphatics from the pelvic viscera
and parietes.

The lumbar lymphatic glands are very large and numerous ; they
are placed in front of the lumbar vertebree, around the aorta and vena
cava. To these proceed the efferent vessels of the glands already men-
tioned, as well as those which accompany several of the branches of the
abdominal aorta.

The efferent absorbent vessels which proceed from the lumbar glands
progressively increase in size, while their number diminishes, and at
length they unite into a few trunks, which, with those of the lacteals,
form the origin of the thoracic duct.

The deep lymphatics of the abdominal wall in part pass along
the circumflex iliac and epigastric arteries, to the external iliac glands ;
the greater number are directed backwards with the ilio-lumbar and
lumbar arteries, and, being joined by the lymphatics from the muscles
of the back, pass behind the psoas muscle to the vertebral column,
where they enter the Jumbar glands.

The lacteals (vasa lactea, chylifera) commence in the coats of the
intestines by a very close plexus, and extend to the thoracic duct, in
which they all terminate : they are far more numerous in the small
than in the large intestine, so that they abound in the mesentery,
and particularly in that of the jejunum and ileum. ‘Two series
of absorbent vessels are found along the tube of the intestine,
having different positions and directions: those nearest to the outer
surface of the intestine run longitudinally in the course of the canal,
lying beneath the peritoneal coat, whilst others, placed more deeply
between the muscular and mucous coats, run transversely round the
intestine, and are directed thence with the arteries and veins along the
mesentery, enclosed between the two layers of the peritoneum. (Cruik-
shank, “ Anatomy of the Absorbent Vessels,” p. 162.) Sometimes the
more superficial absorbents of the intestine are named lymphatics, to
distinguish them from the deep set which absorb the chyle from the
cavity of the intestine. According to Teichmann (“ Das Saugader-
system,” 1861, p. 75), the two plexuses have no capillary anastomoses,
but communicate only through valved vessels: this they do freely.
‘The lacteals, having entered the mesentery, take the course of the
blood-vessels, and pass through successive sets of numerous mesenteric
lymphatic glands. °

The mesenteric glands vary in number from a hundred and thirty
to a hundred and fifty ; and in the healthy state are seldom larger than
an almond. They are most numerous in that part of the mesentery
which corresponds with the jejunum ; and they seldom occur nearer to
the attached border of the intestine than two inches. Small glands
in limited numbers are also disseminated irregularly between the folds
of the peritoneum connected with the large intestines.

Having passed through these glands, the lacteals gradually unite as
they approach the attached border of the mesentery, and so become
diminished in number but increased in size, until at length, near the
root of the superior mesenteric artery, only two or three trunks remain,

510 THE ABSORBENT VESSELS.

Fig. 24.—Principan Lympnatio Vessets AND GLanps oF THE ABDOMEN AND PELvIs
(modified from Mascagni). +

a, the abdominal aorta, the upper part of it having been removed to show the deepest
lumbar plexuses of lymphatics ; @’, the vena cava inferior ; 6, the right; ¢, the left crus
of the diaphragm ; d, the right kidney ; e, the suprarenal body; f, the ureter; g, the
psoas muscle ; /, the iliacus ; /, the lower part of the sacrum within the pelvis ; 1, the
commencement of the thoracic duct ; 2, 3, 2, the largest of the lymphatic and lacteal
trunks which join the thoracic duct, the hepatic, splenic, gastric, &c. ; 4, the suprarenal
lymphatics ; 5, the renal, joining some of the lumbar plexus ; 6, the spermatic ; 7, the
lumbar lymphatic vessels and glands ; 7’, some of the lymphatics of the loins ; 8, those
surrounding the common iliac vessels, and proceeding from the lymphatics of the pelvis
and lower limb ; 8’, lymphatics of the abdominal wall; 9, the external iliac ; 10, the
internal iliac receiving those from the sacrum, walls of the pelvis, and at 11, and at 4,
those from the viscera (bladder and rectum) ; 12, lymphatics of the dorsum of the penis
passing to those of the groin ; 13, the deep femoral lymphatics and glands,

LYMPHATICS OF THE ABDOMEN, 511

which end in the thoracic duct. Sometimes, however, six or seven of
these vessels open separately into the commencement of the duct.
Those from the descending colon and its sigmoid flexure usually join
some of the lumbar lymphatics, or turn upwards and open by a sepa-
rate trunk into the lower end of the thoracic duct.

The lymphatics ofthe stomach, like those of the intestines, are
placed, some beneath the peritoneal coat, and others between the
muscular and mucous coats. Following the direction of the blood-
vessels, they become arranged into three sets. Those of one set accom-
pany the coronary vessels, and receiving, as they run from left to right,
branches from both surfaces of the organ, turned backwards near the
pylorus, to join some of the larger trunks. Another series, from the
left end of the stomach, follow the vasa brevia, and unite with the
lymphatics of the spleen: whilst those of the third set, guided by
the right gastro-epiploic vessels, incline from left to right along the
ereat curvature of the stomach, from which they pass backwards, and
at the root of the mesentery, terminate in one of the principal efferent
lacteal vessels.

The lymphatics of the rectum, likewise in two strata, are fre-
quently of considerable size : immediately after leaving the intestine,
some of them pass through small glands which lie contiguous to it ;
finally, they enter the lymphatic glands situated in the hollow of the
sacrum, or those higher up in the loins. At the anus, their capillary
network is continuous with that of the cutaneous lymphatics.

The lymphatics of the spleen are placed, some immediately under
its peritoneal covering, others in the substance of the organ. Both
sets converge to the inner side of the spleen, come into contact with
the blood-vessels, and, accompanying these, pass through a series of
small glands, and terminate in the larger lymphatics of the digestive
organs.

Lymphatics emerge from the vanereas at different points, and join
those derived from the spicen.

The lymphatics of the liver are divisible into three principal sets,
according as they are placed upon its upper or its under surface, or are
spread through its substance with the blood-vessels.

The lymphatic vessels on the wpper surface of the liver incline towards
particular points, and so become distinguishable into groups, of which
four are usually enumerated. 1, From the middle of this surface five
or six branches run towards the falciform ligament, and, being directed
forwards on this membrane, they unite to form a large trunk, which
passes upwards between two slips of the attachment of the diaphragm,
behind the ensiform cartilage. Having reached the interpleural space
behind the sternum, they ascend through a chain of lymphatic glands
found upon the internal mammary blood-vessels. 2. The second group
consists of vessels which incline outwards towards the right lateral
ligament, opposite to which they unite into one or two larger lym-
phatics ; these pierce the diaphragm, and run forwards upon its upper
surface to join the preceding set of vessels behind the sternum. In
some cases, however, instead of passing into the thorax, they turn
inwards on reaching the back part of the liver, and, running upon the
crus of the diaphragm, open into the thoracic duct close to its com-
mencement. 3. Another set of lymphatics is found upon the left lobe
of the liver ; the vessels of which it is composed, after reaching the

512 THE ABSORBENT VESSELS.

left lateral ligament pierce the diaphragm, and, turning forwards, end
in the anterior glands of the mediastinum. 4. Finally, along the fore
part of the liver some vessels will be observed to turn downwards and
join those placed upon the under surface.

The wnder surface of the liver is covered by an open network of lym-
phatic vessels. On the right lobe they are directed over and under the
gall-bladder to the transverse fissure, where some join the deep lym-
phaties ; whilst others, passing through some scattered lymphatic
glands, are guided by the hepatic artery to the right side of the aorta,
where they terminate in the thoracic duct. Branches also proceed to
the concave border of the stomach, between the folds of the small
omentum, to join with the coronary lymphatics of that organ.

The deep lymphatics of the liver accompany the branches of the portal
vein in the substance of the organ, and pass out of the gland by the
transverse fissure. After communicating with the superficial lym-
phatics, and also with those of the stomach, they pass backwards, and
join, at the side of the cceliac artery, with one of the large dacieal trunks
previously to its termination in the thoracic duct.

The lymphatics ofthe kidney likewise consist of a deep and a super-
ficial set. Those placed upon the surface of the organ are compara-
tively small ; they unite at the hilus of the kidney with other lym-
phatics from the substance of the gland, and then pass inwards to the
lumbar lymphatic glands. The lymphatics of the suprarenal capsules
unite with those of the kidney. The lymphatic vessels of the wreter
are numerous ; they communicate with those of the kidney and bladder,
and for the most part terminate by union with the former.

The lymphatics of the bladder, taking rise from the entire surface
of that organ, enter the glands placed near the internal iliac artery ;
with these are associated the lymphatics of the prostate gland and
vesiculee seminales.

The lymphatics of the uterus, in the unimpregnated state of the
organ, are small, but during the period of gestation they are greatly
enlarged. Issuing from the entire substance of the uterus, the greater
number descend, together with those of the vagina, and pass backwards
to enter the glands upon the internal iliac artery ; thus following the
course of the principal uterine blood-vessels. Others, proceeding from
the upper end of the uterus, run outwards in the folds of peritoneum
which constitute the broad ligaments, and join the lymphatics derived
from the ovaries and Fallopian tubes. The conjoined vessels then ascend
with the ovarian arteries, near the origin of which they terminate
in the lymphatic vessels and glands placed on the aorta and vena cava.

The lymphatics of the testicle commence in the substance of the
gland, and upon the surface of the tunica vaginalis. Collected into
several large trunks, they ascend with the other constituents of the
spermatic cord, pass through the inguinal canal, and accompany the
spermatic vessels in the abdomen to enter some of the lumbar lym-
phatic glands.

LYMPHATICS OF THE THORAX.

The lymphatic glands of the thorax.—Along the course of the
internal mammary blood-vessels there are placed six or seven small
glands, through which pass the lymphatics situated behind the sternum;

THORACIC LYMPHATIC GLANDS. 513

they may be named the anterior mediastinal glands. Between the
intercostal muscles and in the line of the heads of the ribs on the side
of the spine is a set of glands, named intercostal, which receive the
lymphatics from the thoracic parietes and the pleura; their efferent
ducts communicate freely with each other and open into the thoracic
duct. Three or four cardiac lymphatic glands le behind the aortic
arch, and one before it: and another cluster, varying from fifteen to
twenty in number, is found along the cesophagus, constituting the
esophageal glands. The bronchial glands, ten or twelve in number, are

Fig. 325.—Lympnatic VES-
SELS OF THE HEAD AND
Neck AND OF THE UPPER
Part or THE TRUNK

(from Mascagni). 2

The chest and pericar-
dium have been opened on
the left side, and the left
mamma detached and
thrown outwards over the
left arm, so as to expose a
great part of its deep
surface.

The principal lymphatic
vessels and glands are
shown on the side of the
head and face, and in the
neck, axilla, and medias-
tinum. Between the left
internal jugular vein and
the common carotid artery,
the upper ascending part
of the thoracic duct marked
i, and above this, and de-
scending to 2, the arch and
last part of the duct. The
termination of the upper
lymphatics of the dia-
phragm in the mediastinal
glands, as well as the
cardiac and the deep mam-
mary lymphatics, are also
shown.

of much larger size
than those just men-
tioned. The largest of these occupy the interval between the right and
left bronchi at their divergence, whilst others of smaller size rest upon
the first divisions of these tubes for a short distance within the lungs.
In early infancy their colour is pale red; towards puberty, we find
them verging to grey, and studded with dark spots ; at a more advanced
age they are frequently very dark or almost black. In chronic diseases
of the lungs they sometimes become enlarged and indurated, so as to
press on the air-tubes and cause much irritation. They are frequently
the seat of tuberculous deposits.

The deep lymphatics of the thoracic walls are divisible into two
sets, the sternal and the intercostal. The sternal lymphatics, com-
mencing in the muscles of the abdomen, ascend between the fibres of
the diaphragm at its attachment to the ensiform cartilage, and continue

VOL, I. LL

514 THE ABSORBENT VESSELS.

upwards behind the costal cartilages to terminate on the left side in the
thoracic duct, and on the opposite side in the right lymphatic duct.
They receive branches from the upper surface of the liver, and small
branches from the anterior parts of the intercostal spaces. The inier-
costal lymphatics, passing backwards in each intercostal space, receive,
as they approach the spine, branches coming forward through the inter-
transverse space, and enter the intercostal glands, through the efferent
ducts of which their contents are poured on both sides of the body into
the thoracic duct.

The lymphatics of the lungs, like those of other organs, form two
sets, one being superficial, the other deep-seated. Those at the surface
run beneath the pleura, where they form a network by their anasto-
moses. ‘Their number is considerable, but they are sometimes difficult
of demonstration. The deep lymphatics run with the pulmonary blood-
vessels. Both superficial and deep lymphatics converge to the root of the
Inng, and terminate in the bronchial glands. From these, two or three
trunks issue, which ascend along the trachea to the root of the neck,
and terminate on the left side in the thoracic duct, and op the right in
one of the right lymphatic trunks.

The lymphatics of the heart follow the coronary arteries and veins
from the apex of the organ towards the base, where they communicate
with each other, and those of each side are gathered into one trunk.
The trunk from the right side, running upwards over the aortic arch
between the innominate and left carotid arteries to reach the trachea,
ascends to the root of the neck, and terminates in the right lymphatic
duct. The vessel from the left side proceeding along the pulmonary
artery to its bifurcation, passes through some lymphatic glands behind
the arch of the aorta, and ascends at the side of the trachea to ter-
minate in the thoracic duct.

The lymphatics of the esophagus, unlike those of the rest of the
alimentary canal, form only one layer, which lies internal to the mus-
cular coat. They are connected with glands in the neighbourhood, and
after having communicated by anastomoses with the lymphatics of the
lungs, at and near the roots of those organs, they terminate in the
thoracic duct.

The lymphatics of the thymus gland are numerous. According
to Astley Cooper, two large vessels proceed downwards from them on
each cornu, and terminate in the jugular veins by one or more orifices
oneach side. (Anatomy of the Thymus Gland, p. 14.)

LYMPHATICS OF THE UPPER LIMB.

In the upper limb, as in the lower, the lymphatics are arranged in a
deep and a superficial set. These two sets of vessels, together with
the lymphatics of the surface of the greater part of the back, and
those of the mamma and pectoral muscles, converge to the axillary
glands.

The lymphatic glands found in the upper limb below the axilla are
neither large nor numerous ; a few, however, are found in the course of
the brachial artery, and even of the arteries of the forearm ; and one
or more small glands are found in connection with the superficial

AXILLARY LYMPHATIC VESSELS AND GLANDS. 515

Fig. 326.

lymphatics, lying near the
commencement of the basilic
vein, a little above and in front
of the inner condyle of the
humerus.

The axillary glands are
generally ten or twelve in num-
ber: they vary, however, con-
siderably in their number as
well as in their size, in different
individuals ; they are mostly
placed along the axillary ves-
sels, and receive the lympha-
tics which ascend from the
limb; but a few also lie
further forwards on the ser-
ratus magnus near the external
mammary artery, and beneath
the pectoral muscles, and
receive the lymphatics from

Fig. 326.—Suprrricirat Lympwarics or THE Breast,
SHountpEer, AND Upper Livp, FROM BEFORE (after
Mascagni, A. T.) 2
The lymphatics are represented as lying upon the deep

fascia.

a, placed on the clavicle, points to the external jugular
vein ; 0, the cephalic vein; ¢, the basilic vein ; d, radial ;
e, median ; f, ulnar vein ; g, great pectoral muscle cut
and turned outwards ; 1, superficial lymphatic vessels
and glands above the clavicle ; 2, those below the clavicle
partly joining the foregoing and dipping into the triangu-
lar space between the deltoid and pectoral muscles ; 3,
lymphatic vessels and glands placed along the border of
the axilla and great pectoral muscle; 4, upper brachial
and axillary glands and vessels; 5, two small glands
placed near the bend of the arm; 6, radial lymphatic
vessels ; 7, ulnar lymphatic vessels ; 8, 8, palmar arch
of lymphatics; 9, 9’, outer and inner sets of vessels.

the mamma and muscular walls of the chest ;
while others incline downwards at the pos-
terior boundary of the axilla, and are joined
by the lymphatics from the back.

From the glands of the axilla efferent
lymphatic vessels, fewer in number, but
larger in size than the afferent vessels, pro-
ceed along the course of the subclavian artery,
in some parts twining round it. From the
top of the thorax they ascend into the neck.
close to the subclavian vein, and terminate—
those of the left side in the thoracic duct,
those of the right side in the right lymphatic
duct. Sometimes they unite into a single
trunk, which opens separately into the sub-
clavian vein near its termination.

LL

516 THE ABSORBENT VESSELS.

The superficial lymphatics of the upper limb are usually de-
scribed as forming two divisions corresponding with the superficial
veins on the outer and inner borders. On the front of the limb they
arise from an arch formed in the palm of the hand by the union of two
lymphatic vessels proceeding from each finger: becoming more nu-
merous in the forearm, they are found thickly set over its surface,
whence they pass upwards in the arm; the inner vessels in a straight
direction, and those placed further outwards inclining gradually in-
wards over the biceps muscle to reach the axillary glands. On the back
of the hand also two lymphatics proceed from each finger; and from
the copious network on the back of the forearm vessels pass over the
radial margin, and in greater number round the ulnar side to join those
in front. The lymphatic vessels in the front of the upper arm are also
joined by others which pass round each side of the limb, and by some
which descend from the shoulder.

The deep lymphatics of the upper limb correspond with the
deep blood-vessels. In the forearm they consist, therefore, of three
sets, associated respectively with the radial, ulnar, and interosseous
arteries and veins. In their progress upwards some of them have com-
munication near the wrist with the superficial lymphatics ; and some of
them enter the glands which he by the side of the brachial artery
near the bend of the elbow. They all terminate im the glands of the
axilla.

The superficial lymphatics of the chest consist of branches running
under cover of the pectoral muscles, and of subcutaneous vessels, twigs
of which are continued from those on the abdommal wall as low as the
umbilicus, decussating with the vessels which converge to the mguinal
glands.

The superficial lymphatics of the back converge to the axillary
glands from its various regions; from the neck over the surface of the
trapezius muscle, from the posterior part of the deltoid, and from the
whole dorsal and lumbar regions as low as the crest of the ihum; the
branches decussating inferiorly with vessels leading to the inguinal
glands, and likewise crossmg the middle line so as to decussate with
branches of the opposite side. (Mascagni, Tab. xxu., XXI11., XXIV.)

LYMPHATICS OF THE HEAD AND NECK.

The lymphatic glands found on different parts of the head and face
are few and small: those in the neck, on the contrary, are comparatively
very large and numerous.

The cervical glands are placed chiefly on the sides of the neck, and
are divisible into a superficial and a deep series. Of the former, some
lie beneath the base of the inferior maxillary bone ; the remainder,
arranged along the course of the external jugular vein, exist im greatest
number in the angular space behind the lower end of the sterno-mastoid
muscle, where that vein enters the subclavian vein: at this pomt the
cervical glands approach and are connected with the glands of the
axilla. The deep cervical elands are placed along the carotid artery and
internal jugular vein, extending downwards on the sheath of those
vessels as far as the thorax.

The lymphatic vessels of the cranium and face, together with those of
the tongue, pharynx, larynx and other parts of the neck, pass into the

CERVICAL LYMPHATIC VESSELS AND GLANDS. 517

cervical glands. From these glands efferent vessels issue, which pro-
gressively diminish in number during their descent, and unite into two

Fig. 327.

Fig, 327.—Princiran Lympnatic VEssELS AND GLANDS oF THE HEAD AND NEcE
ON THE Ricut Sipe (after Bourgery in part). §

The inner half of the right clavicle and part of the sternum have been removed so as
to expose the arch of the aorta, and the innominate artery and veins : the posterior belly
of the omo-hyoid muscle is semoved ; and the sterno-mastoid, sterno-hyoid, and sterno-
thyroid muscles, and a part of the external jugular rein have been divided so as to expose
the deeper parts.

a, the right innominate vein at the place where it is joined by the principal lymphatic
trunk ; a’, the left vein; b, arch of tke aorta; c, common carotid artery ; d, thyroid
gland crossed by the anterior jugular vein; e, cut surface of the sternum; f, outer part
of the clavicle; 1, submaxillary lymphatic vessels ; 1’, sublingual ; 2, temporal, facial
and parotid ; 3, occipital and posterior auricular ; 4, deep or descending cervical close
to the great vessels; 5, transverse cervical; 6, deep pectoral and axillary; 7, on the
vena cava superior, some of the right mediastinal; 8, on the innominate artery, some of
the deeper cardiac and bronchial; to these last are seen descending some of the lym-
phatics from the thyroid gland and lower part of the neck.

trunks, of which the left one ends in the thoracic duct, and the other in
the right lymphatic duct: sometimes, however, the main cervical
lymphatic vessel terminates separately at the junction of the subclavian
and internal jugular veins, or in one of those veins immediately before
their union.

The lymphatics of the cranium consist of a temporal and an
occipital set. Those of the ¢emporal set descend in front of the ear,

518 THE ABSORBENT VESSELS.

some of the vessels passing through one or two glands usually found
near the zygoma, whilst others enter those situated on the parotid
gland ; all of them terminate in the lymphatic glands of the neck.
The cranial lymphatics of the occipital set, accompanying the occipital
artery, descend to the glands situated behind the ear, on and near the
mastoid process of the temporal bone, and hence join the superficial
lymphatics of the neck.

Within the cranial cavity, lymphatic vessels have been demonstrated
in the pia mater and in the arachnoid membrane. Distinct vessels
have not been traced in the dura mater, nor have they been shown in
the substance of the brain. The trunks of those derived from the pia
mater pass out of the skull with the veins.

In the substance of the brain and spinal cord, according to the observations of
Robin and of His, perivascular spaces or canals surround all the bloodvessels,
even to their capillary ramifications, and are in communication with similar
spaces and lymphatic vessels in the pia mater, and, according to Axel Key and
Retzius, they may be injected from the subarachnoid spaces. The delicate walls
of these perivascular canals agree in their histological character with those of the
capillary lymphatic vessels, and their cavity is filled with a clear lymph-like fluid,
containing numerous lymph corpuscles (Robin, in Journ. de la Physiol., 1859,
p. 537; and His, in Zeitsch. fur Wissensch. Zool., vol. xv. p. 127. See also
Vol. II. p. 572, of this work.)

The superficial lymphatics of the face, more numerous than
those of the cranium, descend obliquely in the course of the facial vein,
and join the submaxillary glands, from six to ten in number, which are
placed beneath the base of the lower maxillary bone ; a few of them in
their descent pass through some glands situated on the buccinator
muscle. The deep lymphatics of the face, derived from those of the
temporal fossa and the cavities of the nose, mouth, and orbit, proceed
outwards in the course of the internal maxillary vein ; and, having
reached the angle of the jaw, they enter the glands in that neigh-
bonrhood.

THE CRANIAL NERVES, 519

Section V.—NEUROLOGY.

THE nervous system consists of central and peripheral parts. To
the first belong those large masses of nervous substance forming the
brain and spinal cord, or great cerebro-spinal centre ; and to the second
belong the various nervous cords, cerebro-spinal and sympathetic, which
are distributed in different parts of the body. Along with these the
nervous system also includes the organs of the external senses and the
ganglia.

The description of the cerebro-spinal centre and of the organs of the
senses will be given in the Second Volume. The present section in-
cludes the descriptive anatomy of the cerebro-spinal and sympathetic
nerves, and of the ganglia connected with them.

THE CEREBRO-SPINAL NERVES.

The nerves directly connected with the great cerebro-spinal centre
constitute a series of symmetrical pairs, of which a certain number
issue from the cranium through different foramina or apertures in its
base, and are thence strictly named cranial. The next following nerve
passes out between the occipital bone and the first vertebra, and the
remaining thirty nerves all issue below the corresponding vertebral
pieces of the spine. The first is sometimes distinguished by the name
of suboccipital, but to the whole series of thirty-one nerves the name
of spinal is usually given.

CRANIAL NERVES.

The cranial nerves, besides being distinguished by numbers in the
order of their passage through the dura mater lining the cranium, have
likewise received other names, according to the place or mode of their
distribution, or their functions.

The number of the cranial nerves has been variously stated as nine
or as twelve by Willis and Scemmerring respectively. Of the nine pairs
of cranial nerves distinguished by Willis, or twelve as enumerated by
Scemmerring, the first six and the last correspond, but the seventh of
Willis is divided into two by Scemmerring, viz., the seventh and the
eighth pairs, or the facial and the auditory nerves, while the eighth of
Willis falls, in the more modern arrangement, into three distinct nerves,
the ninth, tenth, and eleventh, or the glosso-pharyngeal, pneumogastric
and spinal accessory nerves, as in the following table :—

WILLIS. S@MMERRING. OTHER NAMES.
First pair of nerves . é | First pair of nerves. | Olfactory nerves.
Second a : : Second kA . | Optic.
Third 9 ‘ P Third FF . | Common oculo-motor.
Fourth Z - Fourth . . | Pathetic or trochlear.
Fifth - eeeao |) ibid Fp . | Trifacial or trigeminal.
Sixth : : ; Sixth Py . | Abducent ocular.

portio dura . Seventh es . | Facial motor
Reyenth ;, eae mollis Highth ~ . | Auditory.
hin» Ninth - . | Glosso-pharyngeal.
Eighth a {: DANES Tenth i . | Pneumo-gastric.
' n.accessorius Eleventh ,, . | Spinal accessory.

Ninth 5 : ; Twelfth ~ ,, . | Hypoglossal cr lingual

: motor.

520 THE CRANIAL NERVES.

The arrangement of Seemmerring is on the whole the preferable one ;
but as the plan of Willis has long been in general use, it cannot be
entirely abandoned.

Connection with the encephalon.—The roots of the cranial nerves
may be traced for some depth into the substance of the encephalon, a
circumstance which has led to the distinction of the deep and the seper-
Jicial origin, by which latter is understood the place at which the nerve
appears to be attached to the surface of the encephalon.

Fig. 328. — Virw From
BELOW OF THE CONNEC-
TION OF THE PRINCIPAL
NERVES WITH THE
BRAmN (AG vs)

The full description of
this figure will be found
at p. 534 of vol. ii. The
following references apply
to the roots of the nerves ;
I’, the right olfactory tract
divided near its middle;
II, the left optic nerve
Springing from the com-
missure which is con-
cealed by the pituitary
body ; II’, the right optic
tract; the left tract is
seen passing back into
zand e, the internal and
external corpora genicu-
lata; III, the left oculo-
motor nerve; IV, the
trochlear ; V, V, the
large roots of the tri-
facial nerves; ++, the
lesser roots, the + of the
right side is placed on
the Gasserian ganglion ;
1, the ophthalmic; 2, the
superior maxillary, and
3, the inferior maxillary
nerves; VI, the left ab-
ducent nerve; VII, a, 2,
the facial and auditory
nerves; a, VIII, 0, the
glosso-pharyngeal, pneu-
mo-gastric, and spinal ac-
cessory nerves; IX, the
right hypoglossal nerve ;
at o, on the left side, the
roollets are seen cut
short; CI, the left sub-
occipital or first cervical
nerve.

The superficial origin of these nerves is quite obvious. The first pair
are attached to the under surface of the frontallobes, the second to the
posterior portion of the optic thalami, the third to the crura cerebri, the
fourth to the valve of Vieussens, the fifth to the sides of the pons,
and the remainder to the medulla oblongata.

CONNECTION WITH THE BRAIN. 521

The deep connection or origin of these nerves is still in some cases a
matter of considerable uncertainty. Where they can be followed, the
fibres may be traced to, and probably in part arise from, certain col-
lections of grey substance termed “nuclei.” These nuclei are further
connected by other fibres with each other and with the cerebral hemi-
spheres. The deep origin of the first or olfactory nerves is still doubt-
ful; the second pair are connected chiefly with the optic thalami and
corpora quadrigemina; the third and fourth with a nucleus deeply
placed beneath the corpora quadrigemina ; the remainder with a con-
tinuous series of collections of grey matter which lie beneath the floor of
the fourth ventricle and in the central part of the medulla oblongata,
around the central canal, as low down as the decussation of the
pyramids,

Fig. 329.—Larerat View of THE ConnEcTIoN oF THE PrincrpaAL NERVES WITH THE
Brain. (A. T.)

The ful] description of this figure will be found at p. 550, vol. ii. The following references
apply to the roots of the nerves : I, the right olfactory tract cut near its middle ; II, the
optic nerves immediately in front of the commissure; the right optic tract is seen passing
back to the thalamus (7h), corpora geniculata (i, ¢), and corpora quadrigemina (q) ; III,
the right oculo-motor nerve ; IV, the trochlear nerve rising at v, from near the valve of
Vieussens ; V, the trifacial nerve; VI, the abducent ocular ; a, VII, 0, the facial and
auditory nerves, and between them the pars intermedia; a, VIII, 0, the roots of the
glosso-pharyngeal, pneumo-gastric, and spinal accessory nerves; IX, the hypoglossal
nerve ; CI, the separate anterior and posterior roots of the suboccipital nerve.

522 THE CRANIAL NERVES.

Mode of exit from the cranium.—Each of the cranial nerves
in leaving the cranial cavity passes through a foramen or tubular
prolongation of the dura mater: some of these nerves or their main
divisions are contained in distinct foramina of the cranium, others are

Fig. 330.

Fig, 330.—InTERNAL VIEW OF THE BAsE OF THE SKULL, SHOWING THE PLACES OF
EXIT OF THE CrantaL Nerves. (A.T.) 3

The dura mater is left in great part within the base of the skull: the tentorium is
remoyed and the venous sinuses are opened. On the left side a small portion of the roof
of the orbit has been removed to show the relation of certain nerves at the cavernous
sinus and in the sphenoidal fissure. The roots of the several cranial nerves have been
divided at a short distance inside the foramina of the dura mater through which they
respectively pass. I, the bulb of the olfactory nerve lying over the cribriform plate of
the ethmoid bone ; II, the optic nerves ; that of the left side cut short; III, placed on
the pituitary body, indicates the common oculo-motor nerve : IV, the trochlear nerve ;
V, is placed on the left side opposite to the middle of the three divisions of the trige-
minus, which, together with the ganglion and greater root, have been exposed by
opening up the dura mater; on the right side the greater root is seen; VI, placed
below the foramen of exit of the abducent ocular ; VII, placed on the upper part of the
petrous bone opposite the entrance of the facial and auditory nerves into the meatus
auditorius internus; VIII, placed on the petrous bone outside the jugular foramen
opposite the place of exit of the three divisions of the eighth pair of nerves; IX, placed
upon the basilar part of the occipital bone in front of the hypoglossal nerve as it passes
through the anterior condylar foramen. On the left side of the cavernous sinus, the
third, fourth, and ophthalmic division of the fifth nerves are seen keeping towards the
outer side, while the sixth nerve is deeper and close to the internal carotid artery. The
explanation of the remaining references in this figure will be found at p. 480:

GENERAL DISTRIBUTION. 523

grouped together in one foramen. The numerous small olfactory nerves.
descend into the nose through the cribriform plate of. the ethmoid bone ;
the optic nerve pierces the root of the lesser wing of the sphenoid bone;
the third, fourth, and sixth nerves, with the ophthalmic division of the
fifth nerve, pass through the sphenoidal fissure ; the superior maxillary
and inferior maxillary divisions of the fifth pass respectively through
the foramen rotundum and foramen ovale of the great wing of the
sphenoid ; the facial and auditory nerves pierce the petrous bone ; the
glossopharyngeal, pneumogastric, and spinal accessory nerves descend in
separate canals of the dura mater through the anterior part of the jugu-
lar foramen between the petrous and occipital bones ; and the hypoglossal
nerve passes through the anterior condylar foramen of the occipital bone.

General distribution.—The greater number of the cranial nerves
are entirely confined in their distribution within the limits of the head ;
as in the case of the first six pairs and the auditory nerve. Of these,
the olfactory, optic, and auditory are restricted to their respective
organs of sense: while the third, fourth, and sixth are exclusively
motor nerves in connection with the external and internal muscles of
the eyeball and the elevator of the upper eyelid. In the remaining
nerve, the fifth or trifacial, all the fibres derived from the greater root,
and connected with the Gasserian ganglion, are entirely sensory in their
function, and constitute the whole of the first and second and the greater
part of the third division of the nerve: but the last of these divisions
has associated with it the fibres of the lesser or motor root, so as to
become in some degree a compound nerve. As a nerve of sensation the
trifacial occupies in its distribution the greater part of the head super-
ficially and deeply, excepting the interior of the cranium and that part
of the scalp which is situated in the region behind a perpendicular line
passing through the external auditory meatus. The muscular distri-
bution of the inferior division of the fifth nerve is chiefly to the muscles
of mastication.

Of the remaining nerves, the facial and hypoglossal, both exclusively
motor in function, are almost entirely cephalic in their distribution ;
the facial nerve giving fibres to all the superficial and a few of the
deeper muscles of the head and face; and the ninth or hypoglossal
supplying the muscles of the tongue. Of the facial, however, a small
branch joins one of the cervical nerves in the platysma myoides; and
of the ninth, the descending branch supplies in part the muscles of the
neck which depress the hyoid bone and larynx.

Of the three parts of the eighth pair, ranked as cranial nerves in
consequence of their passing through one of the foramina of the cranium,
two, the pneumogastric and spinal accessory, have only a very limited
distribution in the head, and furnish nerves in much greater proportion
to organs situated in the neck and thorax. The first of these, after
giving a small branch to the ear-passages, and supplying nerves to the
larynx and pharynx, the trachea, gullet, the lungs and heart, extends
into the abdominal cavity as the principal nerve of the stomach. The
other, the spinal accessory, which is partially united with the glosso-
pharyngeal and pneumogastric near their origin and thus furnishes
some of their motor fibres, is entirely a motor nerve, and is distributed
in the sterno-mastoid and trapezius muscles. The glosso-pharyngeal
nerve is more strictly confined to the head, supplying branches to the
tongue, pharynx, and part of the ear passages.

524 THE CRANIAL NERVES.

Fig. 331.—A. SemrpracramMatic View oF A Deep Dissection OF THE CRANIAL NERVES
ON THE LEFT SIDE OF THE HEAD (from various authors and from nature). B. Ex-
PLANATORY OUTLINE OF THESAME. A. T. 4

Fig. 331, A.

The Roman numerals from I to IX indicate the roots of tne several cranial nerves as
they lie in or near their foramina of exit. V, is upon the great root of the fifth with the
ganglion in front ; a and 6, in connection with VII, indicate respectively the facial and
auditory nerves; a, , and c, in connection with VIII, point respectively to the glosso-
pharyngeal, pneumo-gastric, and spinal accessory nerves: C I, the suboccipital or first
cervical nerve ; C VIII, the eighth. The branches or eae parts of the nerves are
marked as follows, viz. :—1, frontal branch of the fifth ; 2, lachrymal passing into the
gland ; 3, nasal passing towards the internal orbital foramen and giving the long twig
to the ciliary ganglion (4’) ; 3’, external branch of the internal nasal nerve ; 4, lower
branch of the third or oculo- motor nerve ; 5, the superior maxillary division of the fifth
passing into the infraorbital canal; 5’, its issue at the infraorbital foramen and distri-
bution as inferior palpebral, iateral nasal, and superior labial nerves (5"); 6, ganglion of
Meckel and Vidian nerve passing back from it ; 6’, palatine and other nerves descending
from it ; 6", superior petrosal nerve ; 7, posterior . superior dental nerves ; 7’, placed in
the arte maxillare, which has been opened, points to the anterior superior dental
nerves ; 8, inferior maxillary division of the fifth immediately below the foramen ovale ;
8’, some of the muscular branches coming from it; 8+, the anterior auricular branch
cut short, and above it the small petrosal nerve to join the real nerve; 9, buccal and in-
ternal pterygoid ; 10, lingual or gustatory nerve ; 10’, its distribution to the side and front

GENERAL DISTRIBUTION. 525

of the tongue and to the sublingual glands ; 10", the submaxillary ganglion connected with
the gustatory nerve; below 10, the chorda tympani passing back from the gustatory to
join the facial nerve above 12; 11, inferior dental nerve ; 11’, the same nerve and part

Fig. $31, B.

7 fms
=, ofa f

[Pairs

of its dental distribution exposed by removal of the jaw ; 11”, termination of the same
as mental and inferior labial nerves ; 12, the twigs of the facial nerve to the posterior
belly of the digastric and to the stylo-hyoid muscle immediately after its exit from the
stylo-mastoid foramen ; 12’, the temporo-facial division of the facial ; 12”, the cervico-
facial division ; 13, the trunk of the glosso-pharyngeal passing round the stylo-pharyn-
geus muscle after giving pharyngeal and muscular branches ; 13’, its distribution on the
side and back part of the tongue; 14, the spinal accessory nerve, at the place where it
crosses the ninth and gives a communicating branch to the pneumo-gastric and glosso-
pharyngeal nerves ; 14’, the same nerve after having passed through the sterno-mastoid
muscle uniting with branches from the cervical nerves ; 15, ninth nerve ; 15’, its twig to
the thyro-hyoid muscle ; 15", its distribution in the muscles of the tongue ; 16, descendens
noni nerve giving a direct branch to the upper belly of the omo-hyoid muscle, and
receiving the communicating branches 164 from the cervical nerve ; 17, pneumo-
gastric nerve ; 17’, its superior laryngeal branch ; 17", external laryngeal twig; 18,
superior cervical ganglion of the sympathetic nerve, uniting with the upper cervical
nerves, and giving at 18’ the superficial cardiac nerve ; 19, the trunk of the sympa-
thetic ; 19, the middle cervical ganglion, uniting with some of the cervical nerves, and
giving 19", the large middle cardiac nervé ; 20, continuation of the sympathetic nerve
down the neck ; 21, great occipital nerve ; 22, third occipital.

526 THE CRANIAL NERVES.

On the preceding two pages, Fig. 531 is introduced in illustration of the general
view of the distribution above given. In this figure the cranium and orbit have
been opened up to the depth of the several foramina through which the nerves
pass. The greater part of the lower jaw has also been removed on the left side,
and the tongue, pharynx, and larynx are partially in view. The occipital bone
has been divided by an incision passing down from the occipital tuberosity and
through the condyle tothe left of the foramen magnum. ‘The cervical vertebree
have been divided to the left of the middle, and the sheath of the spinal cord
opened so as to expose the roots of the cervical nerves.

OLFACTORY NERVE.

The first or olfactory nerve, as it is usually termed, or ¢ract, as it has
been more correctly designated, is the special nerve of the sense of
smell. It lies on the under (orbital) surface of the frontal lobe of the
cerebrum, lodged in a sulcus (olfactory sulcus) to the outer side of and
parallel to the longitudinal median fissure. In front the tract swells into
an oval enlargement, the olfactory bulb, which lies in the same sulcus, and
from which small nerves descend, through the cribriform plate, into the
nose. ‘The olfactory tract and bulb contain a considerable quantity of
grey matter, and, in respect of structure, connections, and development,
are to be regarded rather as constituent parts of the cerebrum than as
a true nerve,—the true peripheral olfactory nerves taking origin from
the lower surface of the bulb. In accordance, however, with the most
common practice in anatomical works, the nerve will be here described
as arising at the commencement of the tract in the brain. A fuller
description of the tract and bulb will be found in the account of the
cerebrum (Vol. ii., pp. 536 and 562).

Surface attachment.—At its posterior extremity the olfactory tract
widens out and is attached to the under surface of the frontal lobe, in
front of the anterior perforated space, by means of three roots, named
external, middle and internal, which pass in different directions.

The external or long root consists of a band of medullary fibres, which
passes, in the form of a white streak, outwards and backwards along
the anterior margin of the perforated space, towards the posterior border
of the Sylvian fissure, where it disappears.

The middle or grey root (tuber olfactorium) is of a pyramidal shape,
and consists of grey matter on the surface, which is prolonged from that
of the adjacent part of the anterior lobe and of the perforated space.
Within it there are white fibres, which are sometimes described as alone
constituting the middle root.

The internal root (short root, Scarpa), which cannot always be demon-
strated, is composed of white fibres which may be traced from the inner
and posterior part of the anterior lobe.

Deep origin.—This is still doubtful. The outer root has been
traced by different observers to the island of Reil, the optic thalamus
(Valentin), and to a nucleus in the substance of the temporo-sphenoidal
lobe in front of the anterior extremity of the hippocampus (Rolando,
Luys, Foville. This agrees also with Ferrier’s experimental localisation
of the sense of smell in the monkey). The fibres of the inner root have
been thought to be connected with the anterior extremity of the gyrus
fornicatus, or to cross over to the opposite hemisphere. The fibres of
the middle root have been said by some to join those of the inner root,
by others to be connected with the corpus striatum.

THE OLFACTORY NERVE. 527

Distribution.—The olfactory nerve is exclusively distributed to the
nasal fossze.

From the under surface of the olfactory bulb about twenty branches
proceed through the holes in the cribriform plate of the ethmoid bone,
each invested by tubular prolongations of the membranes of the brain.
These tubes of membrane vary in the extent to which they are con-
tinued on the branches: the offsets of the dura mater sheathe the
filaments, and join the periosteum lining the nose; those of the pia
mater and arachnoid become blended with the neurilemma of the
nerves.

Big. 332. Disrrrpution oF THE OLFAcToRY NERVES ON THE SEPTUM oF THE NosR
(from Sappey after Hirschfeld and Leyeillé). 2

The septum is exposed and the anterior palatine canal opened on the right side. I,
placed above, points to the olfactory bulb, and the remaining Roman numbers to the
roots of the several cranial nerves; 1, the small olfactory nerves as they pass through the
eribriform plate ; 2, internal or septal twig of the nasal branch of the ophthalmic nerve ;
3, naso-palatine nerves. (See fig. 339 for a view of the distribution of the olfactory
nerves on the outer wall of the nasal fossa.)

The branches are arranged in three sets. Those of the inner set,
lodged for some distance in grooves on the surface of the bone, ramify
in the pituitary membrane of the septum ; the outer set extend to the
upper two spongy bones and the smooch surface of the ethmoid bone in
front of these ; and the middle set, which are very short, are confined
to the roof of the nose. The distribution of the olfactory nerve is con-
fined to the upper part of the nasal fossa ; none of the branches reach
the lower spongy bone.—(See Anatomy of the Nose.)

OPTIC NERVE.

The second pair or optic nerves of the two sides meet each other at
the optic commissure (chiasma), where they partially decussate. From
this point they may be traced backwards round the crura cerebri, under
the name of the optic tracts.

Surface attachment.—LEach optic tract arises from the posterior
part of the optic thalamus and the corpora geniculata. As it leaves
the under part of the thalamus, it makes a sudden bend forwards and
then runs obliquely across the under surface of the cerebral peduncle,

£23 THE CRANIAL NERVES.

in the form of a flattened band, which is attached by its anterior surface
to the peduncle ; after this, becoming more nearly cylindrical, it adheres
to the tuber cinereum, from which, and from the lamina cinerea, it is
said to receive an accession of fibres, and thus reaches the optic com-
missure.

Deep origin.—The fibres may be traced into the substance of the
optic thalamus and the corpora geniculata, and to the anterior of the
corpora quadrigemina. The fibres which come from the anterior corpus
quadrigeminum arise from the cells of that body. Those connected
with the internal and external corpus geniculatum are in part connected
with the cells of those bodies, in part pass through them to reach the
optic thalamus. The fibres which pass into the thalamus beneath the
inner corpus geniculatum, between it and the crus (and have been
described as a middle root of the tract), arise, according to Meynert,
from the cells of the lower stratum of the thalamus. ‘The fibres which
arise in the base are derived from the lamina cinerea and also from a
“basal optic ganglion,” which lies on the outer side of the tuber cine-
reum, and sends fibres to the optic nerve of the same side.

Course and distribution.—In the commissure, or chiasma, the nerve
fibres of the two sides undergo a partial decussation. The outer fibres
of each tract continue onwards to the eye of the same side: the
inner fibres cross over to the opposite side; and fibres have been de-
scribed as running from one optic tract to the other along the posterior
part of the commissure, while others pass between the two optic
nerves in its anterior part (Mayo). The outer fibres of each tract
which do not decussate are much less numerous than those which cross
to the opposite side. The decussating fibres are arranged in alternate
layers.

The view before stated is that most commonly given as to the structure of the
commissure ; but it is right to state that its accuracy has been called in question
by several observers who hold, both on anatomical and physiological grounds,
that all the fibres from one tract cross into the optic nerve of the opposite side.
The point appears to be still undecided. In many fishes the optic nerves do not
unite in a commissure but merely cross, each to the side opposite to that of its
origin. (See Waller, Proc. Roy. Soc. vol. viii, Biesiadecki, Wien. Sitzungsb, 1861,
p. 86, and Michel, Archiv fur Ophthalm. 1873, p. 59.).

In front of the commissure, the nerve diverges from its fellow and
acquires greater firmness. It enters the foramen opticum, by which it
reaches the orbit.

Within the orbit it forms a cylindrical trunk, thick and strong, with
a uniform surface. On dissection it is seen to consist of a number of
separate bundles of nerve fibres, imbedded in tough fibrous tissue pro-
longed from the dura mater, and perforated in the centre by the small
arteria centralis retinee, which passes into it soon after it enters the
orbit. It is surrounded by the recti muscles, and, entering the eyeball
posteriorly a little to the inside of its middle, it pierces the sclerotic

and choroid coats, and expands in the retina.—(See the Anatomy of
the Eye.)

THIRD PAIR OF NERVES.

This nerve, the common motor nerve of the eyeball (motorius oculi),
gives branches to all the muscles of the orbit, with the exception of the
superior oblique and external rectus,

THE THIRD PATR, 529

Surface attachment.—The nerve is attached to the inner surface
of the crus cerebri in the interpeduncular space, immediately in front
of the pons. Each nerve consists of a number of funiculi which arise
in an oblique line from the surface.

Deep origin.—The fibres, diverging, pass backwards through the
substance of the crus, some through the locus niger, some through the
tegmental nucleus, to reach the grey matter in which the majority of
themend. This is a collection of large multipolar nerve-cells, lying on
each side close to the middle line, beneath the thick layer of grey
matter which forms the floor of the aqueduct of Sylvius, and below
the corpora quadrigemina. The anterior portion of the nucleus,
beneath the anterior of the corpora quadrigemina, is that in which
the fibres of the third nerve end, the posterior portion giving origin
to some of the fibres of the fourth nerve.

A few fibres are said to run downwards in the pons, among its longi-
tudinal fibres. #

Fig. 333,—VIEW FROM ABOVE Fic. 333.
oF THE UppermMost Nurves
OF THE ORBIT, THE GaAs-
SERIAN GaNnGLion, &c. (from
Sappey after Hirschfeld and
Leveillé), 2

I, the olfactory tract passing
forwards into the bulb ; II, the
commissure of the optic nerves ;
III, the oculo-motor ; IV, the
trochlear nerve ; V, the greater
root of the fifth nerve, a small
portion of the lesser root is
seen below it; VI, the sixth
nerve; VII, facial ; VIII, audi-
tory ; IX, glosso-pharyngeal ;
X, pneumo-gastric ; XI, spinal
accessory ; XII, hypoglossal ;
1, the Gasserian ganglion; 2,
ophthalmic nerve ; 3, lachrymal
branch ; 4, frontal ; 5, external
frontal or supraorbital; 6,
internal frontal; 7, supra-
trochlear branch; 8, nasal
nerve ; 9, infratrochlear
branch ; 10, internal nasal
passing through the internal
orbital foramen ; 11, anterior
deep temporal proceeding from
the buccal nerve ; 12, middle
deep temporal ; 13, posterior
deep temporal arising from the
masseteric ; 14, origin of the temporo-auricular ; 15, great superficial petrosal nerve.

Course and distribution.—Cylindrical and firm, like the other
motor nerves, the third nerve, quitting the investment of the arachnoid
membrane, pierces the inner layer of the dura mater close to the poste-
rior clinoid process, and proceeds towards the sphenoidal fissure, lying
in the external fibrous boundary of the cavernous sinus.

The third nerve divides near the orbit into two parts, which are cort-

tinued into that cavity between the heads of the external rectus muscle,
VOL. I. M M

530 THE CRANIAL NERVES.

and are separated one from the other by the nasal branch of the oph-
thalmic nerve.

The wpper, the smaller part, is directed inwards over the optic nerve
to the superior rectus muscle of the eye and the elevator of the eyelid,
to both of which muscles it furnishes branches.

The dower and larger portion of the nerve separates into three
branches ; of these one reaches the inner rectus; another the lower
rectus; and the third, the longest of the three, runs onwards between
the lower and the outer rectus, and terminates below the ball of the eye
in the inferior oblique muscle. The last-mentioned branch is connected
with the lower part of the lenticular ganglion by a short thick cord,
and gives two filaments to the lower rectus muscle.

The several branches of the third nerve enter the muscles to which
they are distributed on the surface which in each is turned towards
the eyeball.

Varieties.—A branch of the third nerve has been found supplying the external
rectus in a case in which the sixth nerve was wanting (Generali, quoted by
Henle). The branch to the inferior oblique muscle was seen by Arnold to pass
through the lowe~ part of the lenticular ganglion; and by Henle to pieree the
inferior rectus.

In the outer wall of the sinus the third nerve is said to be connected with the
first division of the fifth nerve, and with the cavernous plexus of the sympathetic.

POSITION OF CERTAIN NERVES AT THE CAVERNOUS SINUS, AND AS
THEY ENTER THE ORBIT.—There are several nerves, besides the third,
placed close together at the cavernous sinus, and entering the orbit
through the sphenoidal fissure. To avoid repetition hereafter, the rela-
tive positions of these nerves may now be described. The nerves thus
associated are the third, the fourth, the ophthalmic divisions of the fifth,
and the sixth.

At the cavernous sinus.—In the dura mater which bounds the
cavernous sinus on the outer side, the third and fourth nerves and the
ophthalmic division of the fifth are placed, as regards one another, in
their numerical order both from above downwards and from within out-
wards. ‘The sixth nerve is placed separately from the others close to
the carotid artery, on the floor of the sinus and internally to the fifth
nerve. Near the sphenoidal fissure, through which they enter the orbit,
the relative position of the nerves is changed, the sixth nerve being
here close to the rest, and their number is ‘augmented by the division
of the third and the ophthalmic nerves—the former into two, the latter
into three parts.

In the sphenordal fissure—The fourth and the frontal and lachrymal
branches of the fifth, which are here higher than the rest, lie on the
same level, the fourth being the nearest to the inner side, and enter
the orbit above the muscles. The remaining nerves pass between the
heads of the outer rectus muscle, in the following order from above
downwards; the upper division of the third, the nasal branch of the
fifth, the lower division of the third, and, lowest of all, the sixth.

FOURTH PAIR OF NERVES.

The fourth (nervus trochlearis, n. patheticus) is the smallest of the
cranial nerves, and is distributed entirely to the upper oblique muscle
of the orbit.

Surface attachment.—Each nerve appears at the outer side of the

THE FOURTH PAIR. 531

crus cerebri immediately in front of the pons. Each nerve may be
traced backwards round the peduncle to a place below the corpora
quadrigemina where it arises from the upper part of the valve of
Vieussens.

Deep origin.—Entering the substance of the valve the fibres of each
nerve separate into three groups. which follow different directions.

1. The fibres of an anterior group pass obliquely forwards and up-
wards in the wall of the aqueduct of Sylvius to end in the posterior part
of the nucleus beneath the floor of the aqueduct, which is common to the
third and fourth nerves.

2. Other descending fibres pass down on the outer side of the locus
coeruleus to the neighbourhood of the nucleus of the fifth nerve.

3. The fibres of a third group pass transversely inwards in the sub-
stance of the velum, decussating with those of the opposite side, and
join the ascending or descending fibres of the opposite nerve

Fig. 334.—ViEew FROM ABOVE OF THE Motor NERVES Fig. 334.
OF THE EYEBALL AND ITs Musctes (after Hirsch-
feld and Leyeillé, altered.) GBT)

The ophthalmic division of the fifth pair has been
cut short ; the attachment of the muscles round the
optic nerve has been opened up, and the three upper
muscles turned towards the inner side, their anterior
parts being removed ; a part of the optic nerve is
cut away to show the inferior rectus ; and a part of
the sclerotic coat and cornea is dissected off showing
the iris, zona ciliaris, and choroid coat, with the:
ciliary nerves.

a, the upper part of the internal carotid artery
emerging from the cavernous sinus ; 6, the superior
oblique muscle ; 0’, its anterior part passing through
the pulley ; c, the levator palpebre superioris ; d,
the superior rectus ; e, the internal rectus ; f, the
external rectus ; f’, its upper tendon turned down ;
g, the inferior rectus; %, insertion of the inferior
oblique muscle.

II, the commissure of the optic nerve ; II’, part
of the optic nerve entering the eyeball ; III, the
common occulo-motor ; IV, the fourth or trochlear
nerve ; V, the greater root of the trigeminus ; V’,
the smaller or motor root ; VI, the abducent nerve ;
1, the upper division of the third nerve separating
from the lower and giving twigs to the levator palpe-
bre and superior rectus ; 2, the branches of the
lower division supplying the internal and inferior
recti muscles ; 3, the long branch of the same nerve
proceeding forward to the inferior oblique muscle,
and close to the number 3, the short thick branch
to the ciliary ganglion : this ganglion is also shown,
receiving from behind the slender twig from the nasal nerve, which has been cut short,
and giving forward some of its ciliary nerves, which pierce the sclerotic coat ; 3’, marks
the termination of some of these nerves in the ciliary muscle and iris after having passed
between the sclerotic and choroid coats ; 4, the distribution of the trochlear nerve to the
upper surface of the superior oblique muscle ; 6, the abducent nerve passing into the
external rectus.

Course and distribution.—From the remoteness of its place of
origin, the part of this nerve within the skull is longer than that of
any other cranial nerve. It enters an aperture in the free border of
the tentorium, outside that for the third nerve, and near the posterior

MM 2

532 THE CRANIAL NERVES.

clinoid process. Continuing onwards through the outer wall of the
cavernous sinus, the fourth nerve enters the orbit by the sphenoidal
fissure, and above the muscles. Its position with reference to other
nerves in this part of its course has been already described.

In the orbit, the fourth nerve inclines inwards above the muscles, and
enters finally the upper oblique muscle at its orbital surface.

While in its fibrous canal in the outer wall of the sinus, the fourth nerve is
joined by filaments of the sympathetic, and not unfrequently is blended with the
ophthalmic division of the fifth. Bidder states that three or more small fila-
ments of this nerve extend to the tentorium as far as the lateral sinus; and has
figured one as joining the sympathetic on the carotid artery. (Neurologische
Beobachtungen, von F. H. Bidder. Dorpat, 1836.)

FIFTH PAIR OF NERVES.

The fifth, or trifacial nerve (nervy. trigeminus), the largest cranial
nerve, resembles a spinal nerve, in respect that it consists of a
motor and a sensory part, and that the sensory fibres pass through a
ganglion while the motor do not. Its sensory division, which is much
the larger, imparts common sensibility to the face and the fore part of
the head, as well as to the eye, the nose, the ear, and the mouth ; and
endows the fore part of the tongue with the powers of both touch and
taste. The motor root supplies chiefly the muscles of mastication.

Surface attachment.—The nerve arises from the side of the pons
Varolii, where the transverse fibres of the latter are prolonged into the
middle crus cerebelli, considerably nearer to the upper than to the lower
border of the pons. The smaller root is at first concealed by the larger,
and is placed a little higher up, there being often two or three cross
fibres of the pons between them. On separating the two roots, the
lesser one is seen to consist of a very few funiculi. In the larger root
the funiculi are numerous, amounting sometimes to nearly a hundred.

Deep origin.—The fibres of the /arge root pass backwards inwards
and slightly downwards as a compact bundle, towards the outer part of
the floor of the fourth ventricle. The chief nucleus, in which most of
the fibres end, is situated to the outer side of the trunk, and consists of
a collection of nerve cells, continuous below with the grey tubercle of
Rolando (caput cornu posterioris). The cellsare small and arranged in
clusters, separated by the delicate fasciculi of origin of the nerve. In
front of this nucleus a number of descending fibres pass down, mingled
with grey matter, to the lower part of the medulla oblongata.

Some fibres of the nerve are said to join the middle peduncle of the
cerebellum ; others pass inwards beneath the floor of the fourth ven-
tricle, decussate at the raphé, and (according to Meynert) ascend on the
opposite side of the medulla.

The small root passes in a curve, with the convexity forwards, to
reach the neighbourhood of the nucleus of the larger root. Its fibres
arise from a group of large nerve cells, situated close to the outer angle
of the fourth ventricle, to the inner side of the fibres of the nerve. A
prolongation from this nucleus extends down the medulla, as far as the
olivary bodies, receding from the surface, and to it, below, some fibres
of origin of the facial nerve are traced.

Course.—The roots of the fifth nerve, after emerging from the
surface of the encephalon, are directed forwards, side by side, to the
middle fossa of the skull, through a recess in the dura mater on the

THE FIFTH PAIR. 533

summit of the petrous part of the temporal bone. Here the larger root
alters in appearance : its bundles of fibres diverge and enter the Gas-
serian ganglion. The fasciculi divide and unite in the expanded part
of the nerve, so as to form a plexiform network. The smaller root
passes inside and beneath the ganglion, without its nerve-fibres being
incorporated in any way with it, and joins outside the skull the lowest
of the three trunks which issue from the ganglion.

Fig. 335.—GENERAL PLAN Fig, 335.
OF THE BRANCHES OF
THE FirrtH Parr (after
a sketch by Charles
Bell). 3

1, Jesser root of the
fifth pair; 2, greater
root passing forwards
into the Gasserian gang-
lion; 38, placed on the
bone above the ophthal-
mic nerve, which is seen
dividing into the supra-
orbital, lachrymal, and
nasal branches, the latter
connected with the oph
thalmic ganglion; 4,
placed on the bone close
to the foramen rotundum,
marks the superior max-
illary division, which is
connected below with the
spheno-palatine ganglion,
and passes forwards to
the infraorbital foramen ;
5, placed on the bone over
the foramen ovale, marks
the submaxillary nerve,
giving off the anterior auri-
cular and muscular bran-
ches, and continued by the
inferior dental to the lower
jaw, and by the gustatory
to the tongue; a, the submaxillary gland, the submaxillary ganglion placed above it in
connection with the gustatory nerve ; 6, the chorda tympani; 7, the facial nerve issuing
from the stylo-mastoid foramen.

The ganglion of the fifth nerve or Gasserian ganglion (ganglion semi-
lunare), occupies a depression on the upper part of the petrous portion
of the temporal bone, near the apex, and is somewhat crescentic in
form, the convexity being turned forwards. It is flattened and striated
on the surface. On its inner side the ganglion is joined by filaments
from the carotid plexus of the sympathetic nerve, and, according to
some anatomists, it furnishes from its back’ part filaments to the dura
mater.

Distribution.—From the fore part, or convex border of the Gas-
serian ganglion, proceed the three large divisions of the nerve. The
highest (first or ophthalmic trunk) enters the orbit ; the second, the
upper maxillary nerve, is continued forwards to the face, below the
orbit ; and the third, the lower maxillary nerve, is distributed chiefly to
the external ear, the tongue, the lower teeth, and the muscles of masti-
cation. The first two trunks proceed exclusively from the ganglion

534 THE CRANIAL NERVES.

and are entirely sensory, while the third or inferior maxillary trunk,
receiving a considerable part from the ganglion, has associated with it
also the whole of the fibres of the motor root. and thus distributes
both motor and sensory branches.

I.—OPHTHALMIC NERVE.

The ophthalmic nerve, or first division of the fifth nerve, the smallest
of the three offsets from the Gasserian ganglion, is somewhat flattened,
about an inch in length, and is directed forwards and upwards to the
sphenoidal fissure, where it ends in branches which pass through the
orbit to the surface of the head and to the nasal fossee. In the skull it
is contained in the process of the dura mater bounding externally the
cavernous sinus, and is jomed by filaments from the cavernous plexus
of the sympathetic : according to Arnold, it gives recurrent branches
to the tentorium cerebelli. It also frequently communicates by a con-
siderable branch with the fourth nerve.

BRrANCHES.—Near the orbit the ophthalmic nerve furnishes from its
inner side the nasal branch, and then divides into the frontal and lach-
rymal branches. These branches are transmitted separately through
the sphenoidal fissure, and are continued through the orbit (after
supplying some filaments to the eye and the lachrymal gland) to their
final distribution in the nose, the eyelids and the muscles and integu-
ment of the forehead.

Lachrymal branch.—The lachrymal branch is external to the
frontal at its origin, and is contained ina separate tube of dura mater.
In the orbit it passes along the outer part, above the muscles, to the
outer and upper angle of the cavity. Near the lachrymal gland, the
nerve has a connecting filament with the orbital branch of the superior
maxillary nerve ; and when in close apposition with the gland, it gives
many filaments to that body and to the conjunctiva. Finally, the lach-
rymal nerve penetrates the palpebral ligament externally, and ends in
the upper eyelid, the terminal ramifications being joined by twigs from
the facial nerve.

Varieties.—Turner records a case 1n which on one side the Jachrymal nervy»
was absent, and the gland was supplied by a twig from the orbital branch of
the superior maxillary; on the other side the Jachrymal was small, and was
supplemented by a branch from the orbital. (Journal of Anat., vol. vi. p. 101.)

In consequence of the junction which occurs between the ophthalmic trunk of
the fifth and the fourth nerve, the lachrymal branch sometimes appears 10 be
derived from both these nerves. Swan considers this the usual condition of the
lachrymal nerve. (‘‘ A demonstration of the Nerves of the Human Body,” page
36. London, 1834.)

Frontal branch.—The frontal branch, the largest division of the
ophthalmic, lies, like the preceding nerve, above the muscles in the
orbit, being situated between the elevator of the upper eyelid and the
periosteum. About midway forwards in the orbit, the nerve divides
into two branches, supratrochlear and supraorbital.

a. The supratrochlear branch (internal frontal) is prolonged to the
inner angle of the orbit, close to the point at which the pulley of the
upper oblique muscle is fixed to the orbit. Here it gives downwards a
filament to connect it with the infratrochlear branch of the nasal nerve,
and issues from the cavity between the orbicular muscle of the lids and
the bone. In this position filaments are distributed to the upper eyelid.

THE OPHTHALMIC NERVE. 535

The nerve next pierces the orbicularis palpebrarum and occipito-frontalis
muscles, furnishing twigs to these muscles and the corrugator supercilil,
and after ascending on the forehead, ramifies in the integument.

b. The supraorbital branch (external frontal) passes through the
supraorbital notch to the forehead, and ends in muscular, cutaneous,
and pericranial branches; while in the notch it distributes palpebral
filaments to the upper eyelid.

The muscular branches referred to are comparatively small, and supply the
corrugator of the eyebrow, the occipito-frontalis, and the orbicular muscle of
the eyelids, joining the facial nerve in the last muscle. The cutaneous branches,
among which two (outer and inner) may be noticed as the principal, are placed
at first beneath the occipito-frontalis. The outer one, the larger, perforates the
tendinous expansion of the muscle, and ramifies in the scalp as far back as the
lambdoidal suture. The inner branch reaches the surface sooner than the pre- ©
ceding nerve, and ends in the integument over the parietal bone. The pericranial
branches arise from the cutaneous nerve beneath the muscle, and end in the peri-
cranium covering the frontal and parietal bones,

Ls , :

Fig. 336.—NERVES OF THE Or- Fig. 336.
EIT FROM THE OUTER SIDE
(from Sappey after Hirschfeld

and Leveillé). 3

The external rectus muscle has
been divided and turned down: 1,
the optic nerve ; 2, the trunk o
the third nerve; 3, its upper
division passing into the levator
palpebree and superior rectus ; 4,
its long lower branch to the in-
ferior oblique muscle; 5, the
sixth or abducent nerve joined
by twigs from the sympathetic ;
6, the Gasserian ganglion ; 7,
ophthalmic nerve; 8, its nasal
branch ; 9, the ophthalmic gang-
lion ; 10, its short or motor root ;
11, long sensory root from the nasal nerve; 12, sympathetic twig from the carotid
plexus ; 13, ciliary nerves passing into the eyeball ; 14, frontal branch of the ophthalmic
nerve.

Nasal branch.—The nasal branch (oculo-nasalis), separating from its
parent trunk in the wall of the cavernous sinus, enters the orbit between
the heads of the outer rectus. It then inclines inwards over the optic
nerve, beneath the elevator of the upper eyelid and the superior rectus
muscle, to the inner wall of the orbit, through which it passes by the
anterior internal orbital foramen. In this oblique course across the
orbit it furnishes a single filament to the ophthalmic ganglion, two or
three (long ciliary) directly to the eyeball; and, at the inner side of the
cavity, a considerable branch (infratrochlear), which issues from the
orbit at the fore part.

On leaving the orbit the nasal nerve is directed transversely inwards
to the upper surface of the cribriform plate of the ethmoid bone, and
passing forwards in a groove at its outer edge, within the cranium,
descends by a special aperture, close to the crista galli at the fore part
of the plate, to the roof of the nasal fossa, where it divides into two
branches, one of which (external or superficial nasal) reaches the integu-
ment of the side of the nose, and the other (ramus septi) ramifies in the
pituitary membrane.

535 THE CRANIAL NERVES.

a. The branch to the ophthalmic ganglion (radix longa ganglii ciliaris), very
slender, and about half an inch long, arises generally between the heads of the
external rectus : it lies on the outer side of the optic nerve, and enters the upper
and back part of the ophthalmic ganglion, constituting its long root.

This small branch is sometimes joined by a filament from the cavernous plexus
of the sympathetic, or from the upper branch of the third nerve.

b. The long ciliary nerves, two or three in number, are situated on the inner
side of the optic nerve ; they join one or more of the nerves from the ophthalmic
ganglion (short ciliary), and after perforating the sclerotic coat of the eye, are
continued between it and the choroid to the ciliary muscle, the cornea, and
the iris.

c. The infratrochlcar branch runs forwards along the inner side of the orbit
below the superior oblique muscle, and parallel to the supratrochlear nerve, from
which it receives, near the pulley of that muscle, a filament of connection. The
branch is then continued below the pulley to the inner angle of the eye, and
ends in filaments which supply the orbicular muscle of the lids, the caruncula,
and the lachrymal sac, as well as the integument of the eyelids and side of
the nose.

In the cavity of the nose the nasal nerve ends by dividing into the following
branches,

d. The branch to the nasal septum extends to the lower part of the partition
between the nasal fossee, supplying the pituitary membrane near the fore part of
the septum.

e. The superficial branch (externus seu lateralis) descends in a groove on the
inner surface of the nasal bone ; and after leaving the nasal cavity between that
bone and the lateral cartilage of the nose, it is directed downwards to the tip of
the nose, beneath the compressor naris muscle. While within the nasal fossa,
this branch gives two or three filaments to the fore part of its outer wall, which
extend as far as the lower spongy bone. The cutaneous part is joined by a fila-
ment of the facial nerve.

Varieties.—The frontal may give off a long slender accessory infra-trochlear
(Turner, loc. cit.). Branches of the nasal have been described as entering the
levator palpebré superioris. Luschka describes, also, a spheno-cthmoidal branch
of the nasal, which passes through the posterior ethmoidal foramen and ramifies
in the mucous membrane of the sphenoidal sinus, and of the posterior ethmoidal
cells.

SumMAry.—The first division of the fifth nerve is altogether sensory
in function. It furnishes branches to the ball of the eye and the
lachrymal gland; to the mucous membrane of the nose and eyelids ; to
the integument ‘of the nose, the upper eyelid, the forehead, and ‘the
upper part of the hairy scalp ; and to the muscles above the middle of
the circumference of the orbit. Some of the cutaneous and muscular
filaments join branches of the facial nerve, and the nerve itself commu-
nicates with the sympathetic. :

Cphthalmic Ganglion.

There are four small ganglia connected with the divisions of the fifth
nerve: the ophthalmic canglion with the first, Meckel’s ganglion with
the second, and the otic and submaxillary ganglia with the third.
These eanglia, besides receiving branches from the sensory part of the
fifth, are each connected with a motor nerve from the third, the fifth,
or the facial, and with twigs from the sympathetic ; and the nerves
thus joining the ganglia are “named their roots.

The ophthalmic or lenticular ganglion (gang. semilunare, vel ciliare)
serves as a centre for the supply of nerves—motor, sensory, and sympa-
thetic—to the eyeball. It is a small reddish body, compressed laterally
and somewhat four-sided. It is situated at the back of the orbit,

THE OPHTHALMIC GANGLION. 537

between the outer rectus muscle and the optic nerve, and generally in
contact with the ophthalmic artery; it is joined behind by branches
from the fifth, the third, and the sympathetic nerves; while from its
fore part proceed the ciliary nerves to the eyeball.

UNION OF THE GANGLION WITH NERVES: ITs RooTs.—The posterior
border of the ganglion receives three nerves. One of these, the long root,
a slender filament from the nasal branch of the ophthalmic trunk, joins
the upper part of this border. Another branch, the short root, much
thicker and shorter than the preceding, and sometimes divided into
two parts, is derived from the branch of the third nerve to the inferior
oblique muscle, and is connected with the lower part of the gangtion.
The third root is a very small nerve which emanates from the cavernous
plexus of the sympathetic, and reaches the ganglion with the long upper
root: these two nerves are sometimes conjoined before reaching the
ganglion. Other roots have been assigned to the ganglion. (Valentin,
in Miiller’s Archiv. for 1840.) The ganglion is sometimes very small,
probably from the nerve cells being distributed along the nerves which
are connected with it.

BRANCHES OF THE GANGLION.—From the fore part of the ganglion
arise ten or twelve delicate filaments—the short ciliary nerves. These
nerves are disposed in two fascicuh, arising from the upper and lower
angles of the ganglion, and they run forwards, one set above, the other
below the optic nerve, the latter beg the more numerous. They are
accompanied by filaments from the nasal nerve (long ciliary), with
which some are joined. Having entered the eyeball by apertures in the
back part of the sclerotic coat, the nerves are lodged in grooves on its
inner surface ; and at the ciliary muscle, which they pierce (some filaments
supplying it and the cornea), they turn inwards and ramify in the iris.

II. SUPERIOR MAXILLARY NERVE.

The superior maxillary nerve, or second division of the fifth cranial
nerve, is intermediate in size between the ophthalmic and the inferior
maxillary trunks.

It commences at the middle of the Gasserian ganglion, and, passing
horizontally forwards, soon leaves the skull by the foramen rotundum
of the sphenoid bone. The nerve then crosses the spheno-maxillary
fossa, and enters the infraorbital canal of the upper maxilla, by which
it is conducted to the face. After emerging from the infraorbital fora-
men, it terminates beneath the elevator of the upper lip in branches,
which spread out to the side of the nose, the eyelid, and the upper lip.

BRANCHES.—Near its origin a recurrent branch passes to the dura
mater and middle meningeal artery. In the spheno-maxillary fossa a
temporo-malar branch ascends from the superior maxillary nerve to
the orbit, and two spheno-palatine branches descend to join Meckel’s
ganglion. Whilst the nerve is in contact with the upper maxilla, it
furnishes two posterior dental branches on the tuberosity of the bone,
and an anterior dental branch at the fore part. On the face are the
terminal branches already indicated. .

Orbital branch.—The orbital or temporo-malar branch, a small
cutaneous nerve, enters the orbit by the spheno-maxillary fissure, and
divides into two branches (temporal and malar), which pierce the malar
bone, and are distributed to the temple and the prominent part of the
cheek.

538 THE CRANIAL NERVES.

a. The temporal branch is contained in an osseous groove or canal in
the outer wall of the orbit, and leaves this cavity by a foramen in the
malar bone. When about to traverse the bone, it is joined by a com-
municating filament (in some cases, by two filaments) from the lachrymal
nerve. The nerve is then inclined upwards in the temporal fossa be-
tween the bone and the temporal muscle, and perforating the aponeurosis
over the muscle an inch above the zygoma, ends in cutaneous fila-
ments over the temple. The cutaneous ramifications are united with
the facial nerve, and sometimes with the auriculo-temporal branch of
the third division of the fifth.

b. The malar branch lies at first in the loose fat in the lower angle
of the orbit, and is continued to the face through a foramen in the fore
part of the malar bone, where it is frequently divided into two filaments.
It is distributed to the skin over the malar bone. In the prominent
part of the cheek this nerve communicates with the facial nerve.

Fig. 337.

Fig. 837.—Supertor Maxitnary Nerve AND SOME OF THE OrsITAL NERVES (from
Sappey after Hirschfeld and Leveillé). 2

os)

1, the Gasserian ganglion ; 2, lachrymal branch of the ophthalmic nerve ; 3, trunk
of the superior maxillary nerve ; 4, its orbital branch, joining, at 5, the palpebral twig
of the lachrymal ; 6, origin of its malar twig ; 7,1ts temporal twig ; 8, spheno-palatine
ganglion ; 9, Vidian nerve; 10, its upper branch or great superficial petrosal nerve
proceeding to join the facial nerve (11) ; 12, union of the lower branch of the Vidian nerve
with the carotid branch of the sympathetic ; 13, 14, posterior dental nerves ; 15, terminal
branches of the infraorbital nerves ramifying on the side of the noseand upper lip ; 16,
a branch of the facial uniting with some of the twigs of the infraorbital.

Posterior dental branches.—The posterior dental branches, two
in number, are directed downwards and outwards over the back part
and tuberosity of the maxillary bone.

One of the branches enters a canal in the bone by which it is con-
ducted to the teeth, and gives forwards a communicating filament to
the anterior dental nerve. It ends in filaments to the molar teeth and
the lining membrane of the maxillary sinus, and near the teeth joins a
second time with the anterior dental nerve.

The anterior of the two branches, lying on the surface of the bone, is
distributed to the gums of the upper jaw and to the buccinator muscle.

THE SUPERIOR MAXILLARY NERVE. 539

Anterior dental branch.—The anterior dental branch, leaving the
trunk of the nerve at a varying distance behind its exit from the infra-
orbital foramen, enters a special canal in front of the antrum of High-
more. In this canal it receives the communicating filament from the
posterior dental nerve, and divides into two branches, which furnish
offsets for the front teeth.

(a) The inzer branch supplies the incisor and canine teeth. Filaments from
this nerve enter the lower meatus of the nose, and end inthe membrane covering
the lower spongy bone. Also above the root of the canine tooth, it unites with a
branch of the posterior nasal nerve from Meckel’s ganglion, and forms with it a
small thickening, the ganglion cf Bochdalek, from which branches are described as
descending to the alveolar process and gums of the incisor and canine teeth.
(See Hyrtl’s Lehrbuch, p. 804.) It is probable, however, that this enlargement
contains no nerve cells, and is a minute plexus rather than an actual ganglion.

(®) The exter branch gives filaments to the bicuspid teeth, and is connected
with the posterior dental nerve.

Infraorbital branches. — The infraorbital branches, large and
numerous, spring from the end of the superior maxillary nerve beneath
the elevator muscle of the upper hp, and are divisible into palpebral,
nasal, and labial sets.

Fig. 338.—Derre View oF THE SPHENO-PALATINE GANGLION, AND ITS CONNECTIONS
WITH cTHER Nerves, &c. (from Sappey after Hirschfeld and Leyeillé).

1, superior maxillary nerve ; 2, posterior superior dental ; 3, second posterior dental
branch ; 4, anterior dental , 5, union of these nerves ; 6, spheno-palatine ganglion ; 7,
Vidian nerve ; 8, its great superficial petrosal branch ; 9, its carotid branch ; 10, a part
of the sixth verve, recerving twigs from the carotid plexus of the sympathetic ; 11,
superior cervical sympathetic ganglion; 12, its carotid branch ; 13, trunk of the facial
verve near the knee or bend at the hiatus Fallopii ; 14, glosso-pharyngeal nerve ; 15,
anastemosing branch of Jacobson ; 16, twig uniting it to the sympathetic ; 17, filament
to the fenestra rotunda ; 18, filament to the Eustachian tube ; 19, filament to the fenestra
ovalis ; 20, external deep petrosal nerve uniting with the lesser superficial petrosal ; 21,
internal deep petrosal twig uniting with the great superficial pctrosal.

a. The palpebral branch (there are sometimes two branches) turns upwards to
the lower eyelid in a groove or canal of the bone, and supplies the orbicular
muscle ; it ends in filaments which are distributed to the eyelid in its entire
breadth. At the outer angle of the eyelids this nerve is connected with the
facial nerve.

b. The nasal brenches, directed inwards to the muscles and integument of the
side of the nose, communicate with the cutaneous branch of the nasal nerve.

ec. The labial, the largest of the terminal branches of the upper maxillary

540 THE CRANIAL NERVES.

nerve, and three or four in number, are continued downwards beneath the proper
elevator of the upper lip. Ramifying as they descend, these nerves are distri-
buted to the integument. the mucous membrane of the mouth, the labial glands,
and the muscles of the upper lip.

Near the orbit the infraorbital branches of the superior maxillary
nerve are joined by considerable branches of the facial nerve, the union
between the two being named infraorbital plecus.

Spheno-Palatine Ganglion.

The spheno-palatine ganglion, frequently named Meckel’s or the nasal
ganglion, is deeply placed in the spheno-maxillary fossa, close to the
spheno-palatine foramen. It receives the two spheno-palatine branches
which descend together from the superior maxillary nerve as it crosses the
top of the fossa. It is of greyish colour, triangular in form, and convex
on the outer surface. Its diameter is about the fifth of an inch. The
grey or ganglionic substance does not involve all the fibres of the
spheno-palatine branches of the upper maxillary nerve, but is placed at
the back part, at the point of junction of the sympathetic or deep
branch of the Vidian, so that the spheno-palatine nerves proceeding to
the nose and palate pass to their destination without being incorporated
with the ganglionic mass.

Branches proceed from the ganglion upwards to the orbit, downwards
to the palate, inwards to the nose, and backwards through the Vidian
and pterygo-palatine canals.

ASCENDING BRANCHES.—Thcese consist of three or more very small
twigs, which reach the orbit by the spheno-maxillary fissure, and are
distributed to the periosteum.

Bock describes a branch ascending from the ganglion to the sixth nerve ; Tiede-
mann, one to the lower angle of the ophthalmic ganglion. The filaments described
by Hirzel as ascending to the optic nerve, most probably join the ciliary twigs
which surround that nerve.

DESCENDING BRANCHES.—These are three in number,—the large,
the small, and the external palatine nerves, and are continued chiefly
from the spheno-palatine branches of the superior maxillary. They are
distributed to the tonsil, the hard and soft palate, the gums, and the
mucous membrane of the nose.

a. The larger or anterior palatine nerve descends in the palato-maxillary canal,
and divides in the roof of the mouth into branches, which are received into
grooves in the hard palate, and extend forwards nearly to the incisor teeth. In
the mouth it supplies the gums, the glands, and the mucous membrane of
the hard palate, and joins in front with the naso-palatine nerve. When enter-
ing its canal, this palatine nerve gives a nasal branch which ramifies on the
middle and lower spongy bones; and a little before leaving the canal, another
branch is supplied to the membrane covering the lower spongy bone : these are
inferior nasal branches, Opposite the lower spongy bone springs a small branch.
which is continued to the soft palate in a separate canal behind the trunk of
the nerve.

b. The smaller or posterior palatine branch, arising near the preceding nerve,
enters with a small artery the lesser palatine canal, and is conducted to the soft
palate, the tonsil, and the uvula. According to Meckel, it supplies the levator
palati muscle.

ec. The external palatine nerve, the smallest of the series, courses between the
upper maxilla and the external pterygoid muscle, and enters the external palatine
canal between the maxillary bone and the pterygoid process of the palate bone.
At its exit from the canal it gives inwards a branch to the uvula, and outwards
another to the tonsil and palate. Occasionally this nerve is altogether wanting.

THE SUPERIOR MAXILLARY NERVE. 541

INTERNAL BRANCHES.—These consist of the naso-palatine, and the
upper and interior nasal, which ramify in the lining membrane of the
nasal fossee and adjoining sinuses.

The wpper nasal are very small branches, and enter the back part of the nasal
fossa by the spheno-palatine foramen. Some are prolonged to the upper and
posterior part of the septum, and the remainder ramify in the membrane covering
the upper two spongy bones, and in that lining the posterior ethmoid cells. A
branch, as has been already stated, forms a connection in the wall of the
maxillary sinus, above the eye-tooth, with the anterior dental nerve.

The nasp-palatine nerve, nerve of Cotunnius (Scarpa), long and slender, leaves
the inner side of the ganglion with the preceding branches, and after crossing
the roof of the nasal fossa is directed downwards and forwards on the septum
nasi towards the anterior palatine canal, situated between the periosteum and the
pituitary membrane. The nerves of opposite sides descend to the palate through
the mesial subdivisions of the canal, called the foramina of Scarpa, the nerve of
the right side usually behind that of the left. In the lower common foramen
the two naso-palatine nerves are connected with each other in a fine plexus;
and they end in several filaments, which are distributed to the papille behind
the incisor teeth, and communicate with the great palatine nerve. In its course
along the septum, small filaments are furnished from the naso-palatine nerve
to the pituitary membrane. (See fig. 402. This nerve was discovered inde-
pendently by John Hunter and Cotunnius; see Hunter's ‘‘ Observations on
certain parts of the Animal Economy ;”’ and Scarpa, ‘‘ Annotationes Anatomice,”
lib. ii.)

POSTERIOR BRANCHES.—The branches directed backwards from the
spheno-palatine ganglion are the Vidian and pharyngeal nerves.

The Vidian nerve arises from the back part of the ganglion, which seems to

Fig. 339.

Fig. 339.—Nerves or tur Nosm AND OF THE SPHENO-PALATINE GANGLION FROM TEE
Iyner Sipe (from Sappey after Hirschfeld and Leveillé). 3

1, network of the branches of the olfactory nerve descending upon the membrane
covering the superior and middle turbinated bones ; 2, external twig of the ethmoidal
branch of the nasal nerve ; 3, spheno-palatine ganglion ; 4, ramification of the anterior
division of the palatine nerves ; 5, posterior, and 6, middle divisions of the palatine
nerves ; 7, branch to the membrane on the lower turbinated bone ; 8, branch to the
superior and middle turbinated bones ; 9,naso-palatine branch to the septum cut short ;
10, Vidian nerve ; 11, its great superficial petrosal branch ; 12, its carotid branch ; 13,
the sympathetic nerves ascending on the internal carotid artery.

542 THE CRANIAL NERVES,

be prolonged into it, passes backwards through the Vidian canal, and after
emerging from this divides in the substance of the fibro-cartilage, which fills the
foramen lacerum medium, into two branches: one of these, the superficial
petrosal, joins the facial nerve. while the other, the carotid branch, communi-
cates with the sympathetic. Whilst the Vidian nerve is in its canal, it gives
inwards some small zasal branches, which supply the membrane of the back part
of the roof of the nose and septum, as well as the membrane covering the
end of the Eustachian tube,

The large superxperal petroesal branch of the Vidian nerve, entering the cranium
on the outer side of the carotid artery and beneath the Gasserian ganglion, is di-
rected backwards in a groove on the petrous portion of the temporal bone to the
hiatus Fallopu, and is thus conducted to the aqueductus Fallopii, where it joins
the gangliform enlargement of the facial nerve.

The carotid or sympathetic portion of the Vidian nerve, shorter than the other,
is of a reddish colour and softer texture : it is directed backwards, and on the
outer side of the carotid artery ends in the filaments of the sympathetic surround-
ing that vessel.

In accordance with the view taken of the ganglia connected with the fifth
nerve (p. 536). the superficial petrosal and carotid parts of the Vidian nerve may
be regarded as the motor and sympathetic roots respectively cf the spheno-pala-
tine ganglion ; the spheno-palatine being its sensory root.

The pharyngeal nerve is inconsiderable in size, and, instead of emanating
directly from the ganglion, is frequently derived altogether from the Vidian.
This branch, when a separate nerve, springs from the back of the ganglion, enters
the pterygo-palatine canal with an artery, and is lost in the lining membrane of
the pharynx behind the Eustachian tube.

SumMARY.—The superior maxillary nerve, with Meckel’s ganglion,
supphes the integument above the zygomatic arch, and that of the lower
eyelid, the side of the nose. and the upper lip; the upper teeth, the
ling membrane of the nose; the membrane of the upper part of the
pharynx, of the antrum of Highmore, and of the posterior ethmoidal
cells ; the soft palate. tonsil, and uvula , and the glandular and mucous
structures of the roof of the mouth.

III.—INFERIOR MAXILLARY NERVE.

The lower maxillary nerve, the third and largest division of the fifth
nerve, is made up of two portions, unequal in size, the larger being
derived from the Gasserian ganglion, and the smaller being the slender
motor root of the fifth nerve. These two parts leave the skull by the
foramen ovale in the sphenoid bone, and unite immediately after their
exit. A few lines beneath the base of the skull, and under cover of
the external pterygoid muscle, the nerve separates into two primary
divisions, one of which 1s higher in position and smaller than the other.

The small, anterior, or upper portion, chiefly motor, terminates in branches
to the temporal, masseter, bucciator, and pterygoid muscles. The
larger or lower portion, chefly sensory, divides into the auriculo-temporal,
lingual or gustatory, and inferior dental branches ; 1t likewise supplies
the mylo-hyoid muscle, and the anterior belly of the digastric. Thebranch
to the internal pterygoid muscle, with which also are connected those
proceeding from the otic ganglion to the tensors of the palate and
tympanum, is sometimes counted as a part of the larger division, but is
more correctly regarded as arising from the undivided trunk.

Deep temporal, masseteric and pterygoid branches.—The deep
temporal branches, two in number, anterior and posterior, pass out-
wards above the external pterygoid muscle, close to the bone, and
run upwards, one near the front, and the other near the back of the

THE INFERIOR MAXILLARY NERVE. 543

temporal fossa, beneath the temporal muscle in the substance of which
they are distributed. (See fig. 340.)

The anterior branch is frequently joined with the buccal nerve, and
sometimes with the other deep temporal branch.

The masseteric branch likewise passes above the external pterygoid
muscle, and is directed nearly horizontally outwards, through the sig-
moid notch of the lower jaw to the posterior border of the masseter
muscle, which it enters on the deep surface. It gives a filament or two
to the articulation of the jaw, and occasionally furnishes a branch to
the temporal muscle.

The eaternal pterygoid branch, is most frequently derived from the
buccal nerve. It is sometimes a separate offset from the smaller portion
of the lower maxillary nerve.

The nerve of the internal pterygoid muscle is closely connected at its
origin with the otic ganglion, and enters the inner or deep surface of
the muscle.

The buccal nerve pierces the substance of the external pterygoid
muscle, and courses downwards and forwards to the face, in close contact
with the deep surface of the temporal muscle at its insertion. It fur-
nishes a branch to the external pterygoid muscle as it pierces it, and on
emerging gives two or three ascending branches to the temporal muscle.
It divides into two principal branches, an wpper and a lower, which
communicate with the facial nerve in a plexus round the facial vein, and
are distributed to the integument, the buccinator muscle, and the
mucous membrane. It is chiefly a sensory nerve.

Varieties.—The buccal nerve is sometimes replaced by a branch of the infra-
orbital (Henle). It has been seen to arise as a branch of the inferior dental,
being given off from that nerve within the dental canal, and emerging close to
the alveolar border of the bone (Turner, Nat. Hist. Review, 1864, p.612). Gaillet
(quoted by Henle) desscribes it as arising directly from the Gasserian ganglion,
and piercing the base of the skull by a special foramen between the round and
oyal foramina.

Auriculo-temporal nerve.—The auriculo-temporal nerve takes its
origin close to the foramen ovale. It often commences by two roots,
between which may be placed the middle meningeal artery. It is
directed at first backwards, beneath the external pterygoid muscle, to
the inner side of the articulation of the jaw; then changing its course,
it turns upwards between the ear and the joint, covered by the parotid
gland ; and emerging from this place, it finally divides into two temporal
branches which ascend towards the top of the head.

(a) Communicating branches.——There are commonly two branches which pass
forward round the external carotid artery, and join the facial nerve. Filaments
to the otic ganglion arise near the beginning of the nerve.

(b) Parotid branches are given from the nerve while it is covered by the gland.

(ce) Auricular branches—These are two in number. The loner of the two,
arising behind the articulation of the jaw, distributes branches to the ear below
the external meatus; and sends other filaments round the internal maxillary
artery to join the sympathetic nerve; the wpper branch, leaving the nerve in
front of the ear, is distributed in the integument covering the tragus and the
pinna above the external auditory meatus. Both are confined to the outer surface
of the ear.

(d) Branches to the meatus auditorius.—These, two in number, spring from the
point of connection of the facial and auriculo-temporal nerves, and enter the
interior of the auditory meatus between the osseous and cartilaginous parts, One
of them sends a branch to the membrana tympani.

544 THE CRANIAL NERVES.

(ce) Articular branch.—The nerve to the temporo-maxillary articulation comes
from one of the preceding branches, or directly from the auriculo-temporal
nerve.

(f) Temporal branches-—One of these, the smaller and posterior of the two,
distributes filaments to the attrahens auriculam muscle, the upper part of the
pinna and the integument above it. The anterior temporal branch extends with
the superficial temporal artery to the top of the head, and ends in the integument.
It is often united with the temporal branch of the upper maxillary nerve. Meckel
mentions a communication between this branch and the occipital nerve.

Lingual Nerve.—The, lingual branch (or gustatory nerve), descends
under cover of the external pterygoid muscle, lying to the inner side
and in front of the dental nerve, and sometimes united to it by a cord
which crosses over the internal maxillary artery. It is there joined at

Fig. 340.

Fig. 340.—View or tar Brancues or THE Inrertor Maxrmiary Nerve FROM THE
OUTER SIDE (from Sappey after Hirschfeld and Leveille). 2

The zygoma and ramus of the jaw have been removed, and the outer plate of the jaw
taken off, so as to open up the dental canal ; the lower part of the temporal muscle has
been dissected off the bone, and the masseter muscle turned down.

1, Masseteric branch, descending to the deep surface of the muscle ; 2, a twig to the
temporal muscle ; 5, anterior, and 7, posterior deep temporal nerves ; 3, buccal ; 4, its
union with the facial ; 6, filaments given by the buccal to the external pterygoid muscle ;
8, auriculo-temporal nerve ; 9, its temporal branches ; 10, its anterior auricular branches ;
11, its union with the facial ; 12, sustatory or lingual nerve ; 13,mylo-hyoid nerve ; 14,
inferior dental nerve ; 15, its twigs supplied to the teeth ; 16, mental branches ; 17,
branch of the facial uniting with the mental.

THE INFERIOR MAXILLARY NERVE. 545

an acute angle by the chorda tympani, a small branch connected with
the facial nerve, which descends from the inner end of the Glaserian
fissure. It then passes between the internal pterygoid muscle and the
lower maxilla, and is inclined obliquely inwards to the side of the tongue,
over the upper constrictor of the pharynx, (where this muscle is attached
to the maxillary bone,) and above the deep portion of the submaxillary
gland. Lastly, the nerve crosses Wharton’s duct, and is continued along
the side of the tongue to the apex, in contact with the mucous mem-
brane of the mouth.

(a) Communicating branches are given to the submaxillary ganglion, at the
place where the nerve is in contact with the submaxillary gland. Others forma
plexus with branches of the hypoglossal nerve at the inner border of the hypo-
glossus muscle.

(6) Branches to the mucous membrane of the mouth are given from the nerve
at the side of the tongue, and supply also the gums. Some delicate filaments are
likewise distributed to the substance of the sublingual gland.

(c) The lingual or terminal branches perforate the muscular structure of the
tongue, and divide into filaments, which are continued almost vertically upwards
to the conical and fungiform papillz. Near the tip of the tongue the branches
of the gustatory and hypoglossal nerves are united.

Inferior Dental Nerve.—The inferior dental nerve is the largest of
the three branches of the lower maxillary nerve. It descends under
cover of the external pterygoid muscle, behind and to the outer side of
the gustatory nerve, and, passing between the ramus of the jaw and the
internal lateral ligament of the temporo-maxillary articulation, enters
the inferior dental canal. In company with the dental artery, it pyro-
ceeds along this canal, and supplies branches to the teeth. At the
mental foramen it bifurcates; one part, the incisor branch, being
continued onwards within the bone to the middle line, while the other,
the much larger labial branch, escapes by the foramen to the face.

When about to enter the foramen on the inner surface of the ramus
of the jaw, the inferiordental nerve gives offthe slendermylo-hyoid branch.

(a) The mylo-hyoid branch is lodged in a groove on the inner surface of the
ramus of the maxillary bone, in which it is confined by fibrous membrane, and is
distributed to the lower or cutaneous surface of the mylo-hyoideus and to the
anterior belly of the digastric muscle. This nerve may be traced back within
thesheathof the inferior dental to the motor portion of the inferior maxillary nerve.

(0) The dental branches supplied to the molar and bicuspid teeth correspond to
the number of the fangs of those teeth. Hach branch enters the minute foramen
in the extremity of a fang, and terminates in the pulp of the tooth. Not un-
frequently a collateral branch supplies twigs to several teeth.

(ce) The incisor branch has the same direction as the trunk of the nerve : it ex-
tends to the middle line from the point of origin of the labial branch, and sup-
plies nerves to the canine and incisor teeth.

(d) The labial or mental branch emerging from the bone by the foramen on the
outer surface, divides beneath thedepressor of theangle of the mouth into two parts.

One of these, the outer division, communicating with the facial nerve, sup-
plies the depressor anguli oris and orbicularis oris muscles, and the integument of
the chin.

The inner portion, the larger of the two, ascends to the lower lip beneath the
depressor labii inferioris muscle, to which it gives filaments : the greater number
of the branches end on the inner and outer surfaces of the lip. These inner
branches assist only slightly in forming the plexus of union with the facial nerve.

Varieties.—The lingual has been observed to form a single trunk with the
inferior dental as far as the dental foramen, The inferior dental sometimes has
one or two accessory roots from other divisions of the inferior maxillary. The
most common of these is one which arises from the stem of the inferior maxil-

VOL. I. NON

546 THE CRANIAL NERVES.

lary near the origin of the nerve for the external pterygoid muscle, and which,
from its being occasionally separate from the rect of the inferior dental nerve till
after it enters the dental canal, has been called the lesser inferior dental (Sappolini,
“ Omodei Annali,” 1869). The mylo-hyoid frequently gives off a small branch,
which pierces the mylo-hyoid muscle and joins the lingual nerve. This anasto-
mosis is said by Sappey to be constant.

Otic Ganglion.

The otic ganglion, or ganglion of Arnold, of a reddish-grey colour, is
situated on the deep surface of the lower maxillary trunk, nearly at the
point of junction of the motor fasciculus with that nerve, and around
the origin of the internal pterygoid branch. Its inner surface is close
to the cartilaginous part of the Eustachian tube and the circumflexus
palati muscle; and behind it is the middle meningeal artery.

Connection with nerves—roots.—The ganglion is connected with the
lower maxillary nerve, especially with the branch furnished to the in-
ternal pterygoid muscle, and with the auriculo-temporal nerve, and thus
obtains motor and sensory roots; it is brought into connection with
the sympathetic by a filament from the plexus on the middle meningeal
artery. It likewise receives the small superficial petrosal nerve, which
emerges from the petrous bone by the small foramen internal to the
canal of the tensor tympani muscle, and reaches the exterior of the skull
by piercing the sphenoid bone close to the foramen spinosum. By this
nerve the ganglion forms a communication with the glosso-pharyngeal
and facial nerves.

Branches.—Two small nerves are distributed to muscles—one to the tensor of
the membrane of the tympanum, the other to the circumflexus or tensor palati.

Fig. 341. Fig. 341.—Oric Gane-
LION AND ITS ConnEc-
TIONS FROM THE In-
sipg (from Sappey
after Arnold). 2
This figure exhibits a

view of the lateral por-
tion of the skull with a
part of the nasal fossa
and lower jaw of the
right side ; the petrous
bone has been removed
so as to show the inner
surface of the membrana
tympani and the canal of
the facial nerve.

1, smaller motor root
of the fifth nerve passing
down on the inside of
the Gasserian ganglion to
unite with the inferior
maxillary division; 2,
inferior dental nerve
entering the canal of the
lower jaw ; 3, mylo-hyoid
branch, seen also farther down emerging in front of the internal pterygoid muscle. ;
4, lingual or gustatory nerve; 5, chorda tympani; 6, facial nerve in its canal; 7,
auriculo-temporal nerve, enclosing in its loop of origin the middle meningeal artery ;
8, otic ganglion ; 9, small superficial petrosal nerve joining the ganglion ; 10, branch to
the tensor tympani muscle ; 11, twig connecting the ganglion with the temporo-auricular
nerve ; 12, twig to the ganglion from the sympathetic nerves on the meningeal artery ;
13, branch to the internal pterygoid muscle ; 14, branch to the tensor palati muscle.

THE SUBMAXILLARY GANGLION. 547

Submaxillary Ganglion.

The submaxillary or Imgual ganglion is placed above the deep portion
of the submaxillary gland, and is connected by filaments with the
lingual nerve. It is about the size of the ophthalmic ganglion, and
triangular or fusiform in shape. By the upper part or base it receives
branches from nerves which may be regarded as its roots, whilst from
the lower part proceed the filaments which are distributed from the
ganglion.

Connection with nerves—roots.—This ganglion receives filaments from
the lingual nerve, and likewise, at its back part, a root which appa-
rently comes from the lingual nerve, but is in reality derived from the
chorda tympani, which is prolonged downwards in the sheath of the
lingual nerve. It receives also small twigs from the sympathetic fila-
ments on the facial artery.

BRANCHES.—Some nerves, five or six in number, radiate to the
substance of the submaxillary gland. Others from the fore part of
the ganglion, longer and larger than the preceding, end in the mucous
membrane of the mouth, and in Wharton’s duct.

Accordmg to Meckel (“* De quinto pare,” &c.), a branch occasionally descends in
front of the hyo-glossus muscle, and after joining with one from the hypoglossal
nerve, ends in the genio-hyo glossus muscle.

It may be noticed that while the branches from the otic ganglion pass exclu-
sively so muscles, the submaxillary ganglion gives no muscular offsets.

SumMary.—Cutaneous filaments of the inferior maxillary nerve
ramify on the side of the head, and the external ear, in the auditory
passage, the lower lip, and the lower part of the face ; sensory branches
are supplied by it to the greater part of the tongue; and branches are
furnished to the mucous membrane of the mouth, the lower teeth and
gums, the salivary glands, and the articulation of the lower jaw.

This nerve supplies the muscles of mastication, viz., the masseter,
temporal, and two pterygoid ; also the buccinator, the myio-hyoid, and
the anterior belly of the digastric ; and from the otic ganglion proceed
the branches to the circumflexus palati and tensor tympani muscles.

SIXTH PAIR OF NERVES.

Surface Attachment.—The sixth cranial nerve (abducens) motor
ocull externus, takes 1ts apparent origin from between the pyramidal
body and the pons Varolii by means of a larger and a smaller bundle.
It is connected with the pyramid, and to a small extent with the pons
also.

Deep origin.—The fibres pass backwards and a little upwards
through the fibres of the pons, parallel with the raphe, to reach a
column of large nerve cells situated beneath the eminentia teres. The
same nucleus gives origin to a large number of the fibres of the facial
nerve, and is termed the common nucleus of the facial and sixth nerves.

Course and Distribution.—The nerve enters the dura mater behind
the dorsum seile, and passing forwards in the floor of the cavernous
sinus, close to the outer side of the carotid artery, enters the orbit
through the sphenoidal fissure, between the heads of the external
rectus muscle, and is entirely distributed to that muscle, piercing it on
the ocular surface. In entering the orbit between the heads of the

NN2

548 THE CRANIAL NERVES.

external rectus muscle, it is beneath the other nerves, but above the
ophthalmic vein. While passing along the internal carotid artery in
the cavernous sinus, it is joined by several filaments of the sympathetic
from the carotid plexus. According to Bock it is joined in the orbit
by a filament from Meckel’s ganglion.—(“ Beschreibung des Fiinften.
Nervenpaares.” 1817.)

Varieties.—Absence upon one side has been recorded, its place being supplied
by a branch from the third nerve. (Generali.)

SEVENTH PAIR OF NERVES,

In the seventh cranial nerve of Willis are comprised two nerves
having a distinct origin, distribution, and function. One of these, the
facial, is the motor nerve of the face; the other, the auditory, is the
special nerve of the organ of hearing. Both enter the internal auditory
meatus in the temporal bone, but they are soon separated from each
other. The facial nerve being the firmer of the two, was termed the
portio dura, the other being called the portio mollis.

FACIAL NERVE.

Surface attachment.—The facial nerves appear, on each side, at
the inferior margin of the pons, and in a line with the roots of the fifth
pair. Each nerve emerges from the medulla oblongata, in the outer
part of the depression between the olivary body and the diverging resti-
form body (inferior peduncle of cerebellum), and is often firmly ad-
herent, as a flattened band, to the lower edge and even for a short
distance to the upper surface of the pons. On its outer side is the
auditory nerve. A separate fasciculus of the facial nerve (intermediate
part) is sometimes attached to both auditory and facial nerves.

Deep origin.—The fibres of the facial nerve course backwards, in-
wards, and a little upwards to reach the outer side of the column of
nerve-cells, which lies beneath the eminentia teres (common nucleus of
sixth and facial nerves). In it many of the fibres end. A few pass
inwards, and cross at the raphe to the opposite side of the medulla.
Other fibres ascend to the upper extremity of the nucleus, around which
they turn, and descend, as a compact bundle, on its inner side. These
fibres finally radiate forwards and outwards to the column of nerve-
cells, prolonged downwards from the motor nucleus of the fifth nerve,
and also to the superior olivary body.

Course.—The facial nerve is inclined outwards with the auditory
nerve, from its place of origin, to the internal auditory meatus. The
facial lies in a groove on the auditory nerve, and the two are united in
the auditory meatus by one or two small filaments. At the bottom of
the meatus the facial nerve enters the aqueduct of Fallopius, and follows
the windings of that canal to the lower surface of the skull. The
nerve passes through the temporal bone at first almost horizontally
outwards, between the cochlea and vestibule ; on reaching the inner
wall of the tympanum it is turned suddenly backwards above the fenestra
ovalis towards the pyramid. At the place where it bends, the nerve
presents a reddish gangliform enlargement, sometimes called the genicu-
late ganglion, which marks the place of junction of several nerves.
Opposite the pyramid it is arched downwards behind the tympanum
to the stylo-mastoid foramen, by which it leaves the osseous canal. It
is then continued forwards through the substance of the parotid gland,

THE FACIAL NERVE. 549

and separates in the gland, behind the ramus of the lower maxilla,
into two primary divisions, the temporo-facial and the cervico-facial,
from which numerous branches spread out over the side of the head,
the face, and the upper part of the neck, forming what is known as the

“ pes anserinus.”

Distribution.— Within the temporal bone the facial is connected
with several other nerves by separate branches ; and immediately after
issuing from the stylo-mastoid foramen, it gives off three small branches,
viz., the posterior auricular, digastric, and stylo-hyoid.

Fig. 342.—Tue Facran Nerve
EXPOSED IN ITs CANAL, WITH
its ConNECTING BRANCHES, &c.
(from Sappey after Hirschfeld
and Leveillé). 2

The mastoid and a part of the
petrous bone have been divided
nearly vertically, and the canal
of the facial nerve opened in its
whole extent from the meatus
internus to the stylo-mastoid
foramen. The Vidian canal has
also been opened from the out-
side. 1, facial nerve in the
horizontal part of the commence-
ment of the canal; 2, its second
part turning backwards; 3, its
vertical portion ; 4, the nerve at
its exit from the stylo-mastoid
foramen ; 5, geniculate ganglion ;
6, large superficial petrosal nerve passing from this ganglion to the spheno-palatine
ganglion, and joined by the small internal petrosal branch ; 7, spheno-palatine ganglion ;
8, small superficial petrosal nerve; 9, chorda tympani; 10, posterior auricular branch
cut short at its origin; 11, branch for the digastric muscle; 12, branch for the stylo-
hyoid muscle ; 18, twig to the stylo-glossus muscle uniting wilh muscular branches
of the glosso-pharyngeal nerve (14 and 15).

Connecting Branches.— Filaments of union with the auditory nerve-—In the
meatus auditorius one or two minute filaments pass between the facial and the
trunk of the auditory nerve.

Nerves connected with the gangliform cnlargement.—About two lines from the
beginning of the aqueduct of Fallopius, where the facial nerve swells into the
gangliform enlargement, it is joined by the large superficial petrosal branch
from the Vidian nerve. This ganglion likewise receives a small branch from
the small superficial petrosal nerve which unites the otic ganglion with the
tympanic nerve of Jacobson, The nerve beyond the ganglion receives the
external superficial petrosal nerve (Bidder), which is furnished by the sympa-
thetic accompanying the middle meningeal artery, and enters the temporal bone
by a canal external to that traversed by the small superficial petrosal.

Chorda Tympani and Nerve to the Stapedius.—The nerve named chorda
tympani leaves the trunk of the facial while within its canal, and crosses the
tympanum to join the lingual branch of the fifth, along which it is conducted
towards the tongue. It enters the back part of the tympanic cavity through a
short canal emerging below the level of the pyramid, close to the ring of bone
giving attachment to the membrame of the tympanum; and being invested by
the mucous lining of the cavity, it is directed forwards across the membrana
tympani and the handle of the malleus, to an aperture at the inner end of the
Glaserian fissure. It then passes downwards and forwards, under cover of the
external pterygoid muscle, and uniting with the lingual nerve at an acute angle,

550 THE CRANIAL NERVES.

descends in close contact with it, and is partly distributed to the submaxillary
ganglion and partly blended with the lingual nerve in its distribution to the
tongue. As this nerve crosses the tympanum, it is said to supply a twig to the
laxator tympani muscle.

The nerve to the stapedius muscle arises from the trunk of the facial opposite
the pyramid, and passes obliquely inwards to the fleshy belly of the muscle.

Fig. 343. Fig. 343.—GeENIcULATE GANGLION oF
THE FactAL NERVE AND ITs CONNEG-
TIONS FROM ABOVE (from Bidder).

The dissection is made in the middle
fossa of the skull on tne right side; the
temporal bone being removed so as to
open the meatus internus, hiatus Fal-
lopii, anda part of the canal of the facial
nerve, together with the cavity of the
tympanum. a, the external ear; 6,
middle fossa of the skull with the
meningeal artery ramifying in it: 1,
facial and auditory nerves in the meatus
auditorius internus; 2, large super-
ficial petrosal nerve; 3, small super-
ficial petrosal nerve lying over the ten-
sor tympani muscle; 4, the external
superficial petrosal joining sympathetic
twigs on the meningeal artery; 5, facial
and chorda tympani; 6, nerves of the
eighth pair.

The chorda tympani is regarded
by some anatomists as a continua-
tion of the great superficial petrosal
nerve. According to Owen, in the
horse and calf, the portio dura being less dense in structure, the Vidian branch
of the fifth may be distinctly seen crossing the nerve after penetrating its
sheath, and separating into many filaments, with which filaments of the seventh
nerve are blended, while a ganglion is formed by the superaddition of grey
matter ; and the chorda tympani is continued partly from this ganglion, partly
from the portio dura. (Hunter's Collected Works, vol. iv., p. 194, note.)

Posterior auricular branch.—This branch arises close to the
stylo-mastoid foramen. In front of the mastoid process, it divides into
an auricular and an occipital portion, and is connected with the great
auricular nerve of the cervical plexus. It is said to be joined by the
auricular branch of the pneumo-gastric nerve.

a. The auricular division supplies filaments to the retrahent muscle
of ue ear, and ends in the integument on the posterior aspect of the
auricle.

b. The occipital branch is directed backwards beneath the small
occipital nerve (from the cervical plexus) to the posterior part of the
occipito-frontalis muscle ; it lies close to the bone, and besides supplying
the muscle, gives upwards filaments to the integument.

_ Digastric and stylo-hyoid branches.—The digastric branch arises
In common with that for the stylo-hyoid muscle, and is divided into
numerous filaments, which enter the digastric muscle: one of these
sometimes perforates the digastric, and joins the glosso-pharyngeal
nerve near the base of the skull.
The stylo-hyoid branch, long and slender, is directed inwards from

BRANCHES OF THE FACIAL NERVE. 551

the digastric branch to the muscle from which it is named. This nerve
is connected with the plexus of the sympathetic on the external carotid
artery.

TEMPORO-FACIAL DIVISION.—The temporo-facial, the larger of the
two primary divisions into which the main trunk of the facial nerve
separates, is directed forwards through the parotid gland. Its ramifi-
cations and connections with other nerves form a network over the side
of the face, extending as high as the temple and as low as the mouth.
Its branches are arranged in temporal, malar, and infraorbital sets.

(a) The temporal branches ascend over the zygoma to the side of the head.
Some end in the anterior muscle of the auricle and the integument of the temple,
and communicate with the temporal branch of the upper maxillary nerve near the
ear, as well as with (according to Meckel) the auriculo-temporal branch of the
lower maxillary nerve. Other branches enter the occipito-frontalis, the orbicu-
laris palpebrarum, and the corrugator supercilii muscles, and join offsets from
the supraorbital branch of the ophthalmic nerve.

(6) The malar branches cross the malar bone to reach the outer side of the
orbit, and supply the orbicular muscle. Some filaments are distributed to both
the upper and lower eyelids: those in the upper eyelid join filaments from the
lachrymal and supraorbital nerves ; and those in the lower lid are connected with
filaments from the upper maxillary nerve. Filaments from this part of the facial
nerve communicate with the malar branch of the upper maxillary nerve.

(c) The infraorbital branches, of larger size than the other branches, are almost
horizontal in direction, and are distributed between the orbit and mouth. They
supply the buccinator and orbicularis oris muscles, the elevators of the upper lip
and angle of the mouth, and likewise the integument. Numerous communica-
tions take place with the fifth nerve. Beneath the elevator of the upper lip these
nerves are united in a plexus with the branches of the upper maxillary nerve;
on the side of the nose they communicate with the nasal, and at the inner angle
of the orbit with the infratrochlear nerve. The lower branches of this set are
connected with those of the cervico-facial division.

Near its commencement the temporo-facial division of the facial is connected
with the auriculo-temporal nerve of the fifth, by one or two branches of consi-
derable size which tum round the external carotid artery; and it gives some
filaments to the tragus of the outer ear,

CERVICO-FACIAL DIVISION.—This division of the facial nerve is
directed obliquely through the parotid gland towards the angle of the
lower jaw, and gives branches to the face, below those of the preceding
division, and to the upper part of the neck. The branches are named
buccal, supramaxillary, and inframaxillary. In the gland, this division
of the facial nerve is joined by filaments of the great auricular nerve
of the cervical plexus, and offsets from it penetrate the substance of
the gland.

(a) The buccal branches are directed across the masseter muscle to the angle
of the mouth ; supplying the muscles, they communicate with the temporo-facial
division, and on the buccinator muscle join with filaments of the buccal branch
of the lower maxillary nerve.

(b) The supramavrillary branch, sometimes double, gives an offset over the side
of the maxilla to the angle of the mouth, and is then directed inwards, beneath
the depressor of the angle of the mouth, to the muscles and integument between
the lip and chin ; it joins with the labial branch of the lower dental nerve.

(c) The inframavillary branches (x. subeutanei colli) perforate the deep cervical
fascia, and, placed beneath the platysma muscle, form arches across the side of
the neck as low as the hyoid bone. Some branches join the superficial cervical
nerve beneath the platysma, others enter that muscle, and a few perforate it to
end in the integument.

552 THE CRANIAL NERVES.

Summary.—The facial nerve is the motor nerve of the face. It is
distributed to most ot the muscles of the ear, and to the muscles of the

Fig. 344. —Scpmrricran DistriButioN oF THE Factat, TRIGEMINAL, AND OTHER NERVES
oF THE Heap (from Sappey after Hirschfeld and Leveillé). 2

a, References to the Facial Nerve.—1, trunk of the facial nerve after its exit from the
stylo-mastoid foramen ; 2, posterior auricular branch ; 3, filament of the great auricular
nerve uniting with the foregoing ; 4, twig to the occipitalis muscle ; 5, twig to the pos-
terior auricular muscle; 6, twig to the superior auricular muscle ; 7, branch to the
digastric ; 8, that to the stylo-hyoid muscle ; 9, superior or temporo-facial division of the
pes anserinus ; 10, temporal branches ; 11, frontal ; 12, palpebral or orbital ; 13, nasal
or infraorbital ; 14, buccal ; 15, inferior or cervico-facial division of the nerve ; 16, labial
and mental branches ; 17, cervical branches.

b, References to the Fifth Nerve.—18, temporo-auricular nerve (of the inferior
maxillary nerve) uniting with the facial, giving anterior auricular and parotid branches,
and ascending to the temporal region ; 19, external frontal or supra-orbital nerve ; 20,
internal frontal ; 21, palpebral twigs of the lachrymal ; 22, temporal branches of the
infratrochlear ; 23, malar twig of the orbito-malar; 24, external nasal twig of the
ethmoidal ; 25, infraorbital nerve ; 26, buccal nerve uniting with branches of the facial ;
27, labial and mental branches of the inferior dental nerve.

c, Cervical Nerves. —28, great occipital nerve from’ the second cervical ; 29, g eat
auricular nerve from the cervical plexus ; 80, lesser occipital ; 31, another branch with
a similar distribution ; 32, superficial cervical, uniting by several twigs with the facial,

THE AUDITORY NERVE. 553

scalp ; to those of the mouth, nose, and eyelids ; and to the cutaneous
muscle of the neck (platysma). It likewise supplies branches to the
integument of the ear, to that of the side and back of the head, as well
as to that of the face and the upper part of the neck.

This nerve is connected freely with the three divisions of the fifth
nerve, and with the submaxillary and spheno-palatine ganglia; with
the glosso-pharyngeal and pneumo-gastric nerves: with the auditory,
and with parts of the sympathetic and the spinal nerves.

Varieties.—The chorda tympani has been found more or less separate from
the trunk of the lingual nerve, and in these cases it is very easy to trace the
distribution of its terminal branches. Thus, in a case reported by Embleton
(Journ, of Anat., vol. vi., p. 217), the chorda applied itself to the inferior dental
nerve, which it only left a line or two above the dental canal, and, passing on,
divided into branches to the submaxillary and sublingual glands, and to the
lingual nerve.

AUDI.ORY NERVE.

The auditory nerve, or portio mollis of the seventh pair, is the special
nerve of the organ of hearing, and is distributed exclusively to the
internal ear.

Surface attachment.—The auditory nerves appear at the lower
border of the pons, on the outer side of and close to the facial nerves.
They are also connected with the lower edge of the pons opposite the
restiform body, from the inner side or middle of which they emerge.

Deep origin.—The fibres of the nerve divide into two nearly equal
parts, of which one, posfertor, winds round the restiform body, while
the other, anterior, passes through its substance. The chief nucleus of
the nerve (inner nucleus) forms a convex prominence in the outer
portion of the lower half of the floor of the fourth ventricle. Its
transverse section is triangular, and it is composed of small, round,
oval and triangular cells. The posterior portion of the auditory nerve,
winding round the restiform body (with which it is connected), reaches
the outer part of this nucleus. The anterior division passes through the
substance of the inferior peduncle of the cerebellum towards the apex of
theinner nucleus. A few of its fibres join the inner nucleus ; the majority,
however, turn outwards to a network of cells and fibres in the posterior
portion of the restiform body (outer nucleus, Lockhart Clarke) to the
outer side of the inner nucleus. Some of the fibres of this division turn
outwards along the restiform body to reach the cerebellum, where they
have been traced to the superior vermiform process. Both portions of
the auditory nerve contain many nerve-cells: in the posterior portion
they constitute a pyriform swelling at the anterior edge of the restiform
body.

Course.—As the auditory nerve is inclined outwards from its connec-
tion with the medulla oblongata to gain the internal auditory meatus, 1t
is in contact with the facial nerve, being only separated from it in part
by a small artery destined for the internal ear. Within the meatus the
two nerves are connected to each other by one or two small filaments.
Finally the auditory nerve bifurcates in the meatus: one division,
piercing the anterior part of the cribriform lamina, is distributed to the
cochlea; the other, piercing the posterior half of the lamina, enters
the vestibule of the internal ear. The distribution of these branches
will be described with the ear. i

554 THE CRANIAL NERVES.

EIGHTH PAIR OF NERVES.

The eighth pair is composed of three distinct nerves—the glosso-
pharyngeal, pneumo-gastric, and spinal accessory, which leave the skull
through the anterior and inner division of the foramen lacerum posti-
cum, to the inner side and in front of the internal jugular vein. Two
of these nerves, the glosso-pharyngeal and pneumo-gastric, are attached
to the medulla oblongata in the same line, and resemble one another
somewhat in their distribution, for both are distributed to the first part
of the alimentary canal. The other, the spinal accessory, takes its
origin chiefly from the spinal cord, and is mainly distributed to muscles ;
but it gives fibres to the first two nerves by its communicating branch.

I._GLOSSO-PHARYNGEAL NERVE.
The glosso-pharyngeal nerve is destined, as the name implies, for the

tongue and pharynx.

Surface attachment.—The nerve arises from the surface of the
restiform body of the medulla by five or six roots, arranged in a vertical
line, the highest being contiguous to the facial and auditory nerves, the
lowest to the highest roots of the pneumogastric.

Deep origin.—The fibres pass inwards and backwards through the
substance of the medulla, to reach the nucleus, a small column of large
nerve-cells placed deeply beneath the lower part of the floor of the
fourth ventricle, between the highest part of the vagal nucleus and the
lower part of the inner auditory nucleus.

Fie, 345. Fig. 345. —Dracrammatic SKetcH
°o

FROM BEHIND OF THE Roots oF THE

NERVEs OF THE Ergutu Pair, witu

THEIR GANGLIA AND CoMMUNICA-

tions (from Bendz).

A, part of the cerebellum above the
fourth ventricle; B, medulla oblon-
gata; C, posterior columns of the spina!
cord; 1, root of the glosso-pharyngeal
nerve ; 2, roots of the pneumo-gastric ;
3, 3, 3, roots of the spinal accessory,
the uppermost number indicating the
filaments intermediate between the
spinal accessory and pneumo-gastric ;
4, jugular ganglion of the glosso-pha-
ryngeal ; 5, petrous ganglion ; 6,
tympanic branch ; 7, ganglion of the
root of the pneumo-gastric ; 8, auri-
cular branch ; 9, long ganglion on the
trunk of the pneumo-gastric: 10,
branch from the upper ganglion to the
petrous ganglion of the glosso-pharyn-
geal; 11, inner portion of the spinal
accessory ; 12, outer portion; 13,
pharyngeal branch of the pneumo-
gastric ; 14, superior laryngeal
branch ; 15, twigs connected with the sympathetic ; 16, fasciculus of the spinal accessory
prolonged with the pneumo-gastric.

Course and distribution.—Directed outwards from its place of
origin over the flocculus to the foramen jugulare, it leaves the skull
with the pneumo-gastric and spinal accessory nerves, but in a separate
tube of dura mater. In passing through the foramen, somewhat in

THE GLOSSO-PHARYNGEAL NERVE. 555

front of the others, this nerve is contained in a groove, or in a canal in
the lower border of the petrous portion of the temporal bone, and
presents, successively, two ganglionic enlargements,—the jugular gang-
lion, and the petrous ganglion.

After leaving the skull, the glosso-pharyngeal nerve appears between
the internal carotid artery and the jugular vein, and is directed down-
wards over the carotid artery and beneath the styloid process and the
muscles connected with it, to the lower border of the stylo-pharyngeus
muscle. Here, changing its direction, the nerve curves inwards to the
tongue, on the stylo-pharyngeus and the middle constrictor muscle of
the pharynx, above the upper laryngeal nerve; and, passing beneath
the hyo-glossus muscle, ends in branches for the pharynx, the tonsil,
and the tongue.

The jugular ganglion, the smaller of the two ganglia of the glosso-
pharyngeal nerve, is situated at the upper part of the osseous groove in
which the nerve is laid during its passage through the jugular foramen.
Its length is from half a line to a line, and the breadth from half to
three-fourths of a line. It is placed on the outer side of the trunk of
the nerve, and involves only a part of the fibres,—a small fasciculus
passing over the ganglion, and joining the nerve below it.

Fig. 346.—Sketcu oF THE TYMPANIC
BRANcH OF THE GLOSSO-PHARYN-
GEAL NERVE, AND 1TS CONNECTIONS
(from Breschet).

A, squamous part of the left tem-
poral bone; B, petrous part: C, in-
ferior maxillary nerve; D, internal
carotid artery; @, tensor tympani
muscle ; 1, carotid plexus; 2, otic
ganglion ; 3, glosso-pharyngeal nerve;
4, tympanic nerve; 5, twigs to the
carotid plexus ; 6, twig to fenestra
rotunda; 7, twig to fenestra ovalis ;
8, junction with the large superficial
petrosal nerve ; 9, small superficial
petrosal ; 10, twig to the tensor tym-
pani muscle; 11, facial nerve; 12,
chorda tympani ; 13, petrous ganglion
of the glosso-pharyngeal; 14, twig to
the membrane of the Eustachian
tube.

The petrous ganglion is
contained in a hollow in the
lower border of the petrous
part of the temporal bone
(receptaculum ganglioli petrosi), and measures about three lines in
length. This ganglion includes all the filaments of the nerve, and
resembles the gangliform enlargement of the facial nerve. From it
arise the small branches by which the glosso-pharyngeal is connected
with other nerves at the base of the skull; these are the tympanic
nerve, and the branches which join the pneumo-gastric and sympathetic.

Connecting branches, and tympanic branch.—From the petrous ganglion

spring three small connecting filaments. One passes to the auricular branch of
the pneumo-gastric, one to the upper ganglion of the sympathetic or vice vers,

556 THE CRANIAL NERVES

and a third to the ganglion of the root of the pneumo-gastric nerve. The last is
not constant,

There is sometimes likewise a filament from the digastric branch of the facial
nerve, which, piercing the digastric muscle, joins the glosso-pharyngeal nerve be-
low the petrous ganglion.

The tympanic branch (nerve of Jacobson) arises from the petrous ganglion, and
is conducted to the tympanum by a special canal, the orifice of which is in the
ridge of bone between the jugular fossa and the carotid foramen. On the inner
wall of the tympanum the nerve joins with a twig from the sympathetic forming a
plexus (tympanic), and distributes filaments to the membrane lining the tym-
panum and the Eustachian tube, as well as one to the fenestra rotunda, and
another to the fenestra ovalis.

From the tympanic nerve are given three connecting branches, by which it
communicates with other nerves; and which occupy channels given off from the
osseous canal through which the nerve enters the tympanum. One branch enters
the carotid canal and joins with the sympathetic on the carotid artery, A second
is united to the large superficial petrosal nerve, as this lies in the hiatus Fallopii.
And the third is directed upwards, beneath the canal for the tensor tympani
muscle, towards the surface of the petrous portion of the temporal bone, where
it becomes the small petrosal nerve ; and under this name it is continued to the
exterior of the skull through a small aperture in the sphenoid and temporal
bones, to end in the otic ganglion. As this petrosal nerve passes the gangliform
enlargement of the facial, it has a connecting filament with that enlargement,
which is by some considered its principal posterior termination.

Jacobson described an interior or internal branch from the tympanic nerve to
the spheno-palatine ganglion.

Branches distributed in the neck.—The carotid branches course along the
internal carotid artery, and unite with the pharyngeal branch of the pneumo-
gastric, and with branches of the sympathetic nerve.

The pharyngcal branches, three or four in number, unite opposite the middle
constrictor of the pharynx with branches of the pneumo-gastric and sympathetic
to form the pharyngeal plevus. Nerves to the mucous membrane of the pharynx
perforate the muscles, and extend upwards to the base of the tongue and the
epiglottis, and downwards nearly to the hyoid bone.

The muscular branches are given to the stylo-pharyngeus and constrictor
muscles.

Tonsilitie branches.—When the glosso-pharyngeal nerve is near the tonsil, some
branches are distributed on that body in a kind of plexus (circulus tonsillaris).
From these nerve offsets are sent to the soft palate and the isthmus of the fauces.

Lingual branches.—The glosso-pharyngeal nerve divides into two parts at the
border of the tongue. One turns to the upper surface of the tongue, supplying
the mucous membrane at its base; the other perforates the muscular structure,
and ends in the mucous membrane on the lateral part of the tongue. Some fila-
ments enter the circumvallate papillee.

Variety.— In one case a branch from the glosso-pharyngeal supplied the
mylo-hyoid muscle and the anterior belly of the digastric, the normal mylo-
hyoid nerve being wanting. (Guy's Hosp. Reports, vol. xiv., p. 436.)

SuMMARY.—The glosso-pharyngeal nerve distributes branches to the
mucous membrane of the tongue, pharynx, tympanum, and Eustachian
tube. The muscles supplied by it are some of those of the pharynx and
base of the tongue. It is connected with the following nerves, viz., the
lower maxillary division of the fifth, the facial, the pneumo-gastric (the
trunk and branches of this nerve), and the sympathetic.

II._PNEUMO-GASTRIC NERVE.
The pneumo-gastric nerve (nervus vagus, par vagum) has the longest
course of any of the cranial nerves. It extends through the neck and
the cavity of the chest to the upper part of the abdomen; and it

THE PNEUMO-GASTRIC NERVE. 557

supplies nerves to the organs of voice and respiration, to the alimentary
canal as far as the stomach, and to the heart.

Surface attachment.—This nerve arises from the restiform body
of the medulla, by twelve or fifteen fine roots, beneath and in a line
with the roots of the glosso-pharyngeal nerves.

Deep origin.—The fibres pass inwards and backwards through the
medulla to a column of nerve-cells beneath the lowest part of the floor
of the fourth ventricle, where they cause a prominence on the surface.
At the point of the calamus scriptorius the nuclei are in contact in
the middle line, but a little higher up they are separated by the nuclei
of the hypoglossal nerve.

Course and distribution.—The filaments by which this nerve
springs from the medulla oblongata close below those of the glosso-
pharyngeal nerve are arranged in a flat fasciculus, which is directed
outwards with that nerve, across the flocculus to the jugular foramen.

Fic. 347.—Diacram or THE Roots Fig, 347.
AND ANASToMOSING BRANCHES OF
THE NERVES OF THE E1cuTH PAtr
AnD Nercapourtne Nerves (from
Sappey after Hirschfeld and Le-
veillé).

1, facial nerve ; 2, glosso-pharyn-
gealw ith the petrous ganglion repre-
sented ; 2’, connection of the digastric
branch of the facial nerve with
the glosso-pharyngeal nerve; 3, pneu-
mo-gastric, with both its gangha re-
presented: 4, spinal accessory; 5,
hypoglossal ; 6, superior cervical
ganglion of the sympathetic ; 7, loop
of union between the two first cer-
vical nerves; 8, carotid branch of
the sympathetic ; 9, nerve of Jacob-
<ov (tympanic), given off from the
petrous ganglion; 10, its filaments
to the <ympathetic ; 11, twig to the
Eustachian tube; 12, twig to the
fenestra ovalis; 13, twig to the
fenestra rotunda; 14, twig of union
with the small superficial petrosal ;
15, twig of union with the large
superficial petrosal; 16, otic gang-
lion; 17, branch of the jugular
fossa, giving a filament to the
petrous ganglion ; 18, union of the
spinal accessory with the pneumo-
gastric; 19, union of the hypo-
glossal with the first cervical nerve ;
20, union between the sterno-mastoid
branch of the spinal accessory and
that of the second cervical nerve; 21, pharyngeal ea. 22, superior iaryngeal nerve ;
23, external laryngeal ; 24, middle cervical ganglion of the sympathetic.

In passing through the opening at the base of the skull the pneumo-
gastric nerve is contained in the same sheath of dura mater, and sur-
rounded by the same tube of arachnoid membrane as the spinal
accessory nerve ; but it is separated from the glosso-pharyngeal nerve
by a process of membrane. In the foramen the filaments of the nerve

558 THE CRANIAL NERVES.

become ageregated together ; and it here presents a ganglionic enlarge-
ment, distinguished as the ganglion of the root of the pneumo-gastric.
After its passage through the foramen, it 1s joined by the accessory

Fig. 348.—Virew or tHe Nerves or THE Eigurn Parr, THEIR DisTRIBUTION AND
CONNECTION ON THE Lert Sipz (from Sappey after Hirschfeld and Leveillé). 4

1, pneumo-gastric nerve in the neck ; 2, ganglion of its trunk ; 3, its union with the
spinal accessory ; 4, its union with the hypoglossal ; 5, pharyngeal branch ; 6, superior
laryngeal nerve ; 7, external laryngeal ; 8, Jaryngeal plexus; 9, inferior or recurrent
laryngeal ; 10, superior cardiac branch ; 11, middle cardiac ; 12, plexiform part of the
nerve in the thorax ; 13, posterior pulmonary plexus ; 14, lingual or gustatory nerve of
the inferior maxillary ; 15, hypoglossal, passing into the muscles of the tongue, giving
its thyro-hyoid branch, uniting with twigs of the lingual ; 16, glosso-pharyngeal nerve ;
17, spinal accessory nerve, uniting by its inner branch with the pneumo-gastric, and by
its outer, passing into the sterno-mastoid muscle ; 18, second cervical nerve ; 19, third ;
20, fourth ; 21, origin of the phrenic nerve ; 22, 23, fifth, sixth, seventh, and eighth
cervical nerves, forming with the first dorsal the brachial plexus ; 24, superior cervical
ganglion of the sympathetic ; 25, middle cervical ganglion ; 26, inferior cervical ganglion
united with the first dorsal ganglion ; 27, 28, 29, 80, second, third, fourth, and fifth
dorsal ganglia.

COURSE OF THE PNEUMO-GASTRIC NERVE. 5a9

part of the spinal accessory nerve, and a second ganglion is formed
upon it, the ganglion of the trunk of the nerve. Several communi-
cations are at the same time established with the surrounding nerves.

The upper ganglion, or ganglion of the root of the pneumo-
gastric nerve, situated in the foramen jugulare, is of a greyish colour,
nearly spherical, and about two lines in diameter; it has filaments
connecting it with other nerves, viz., with the facial, the petrous
ganglion of the glosso-pharyngeal, the spinal accessory, and the
sympathetic.

The lower ganglion, or ganglion of the trunk of the pnenmo-gastric
nerve, is placed about half an inch beyond the preceding. Occupying
the trunk of the nerve outside the skull, it is of a flattened cylindrical
form and reddish colour, and measures about ten lines in length and
two in breadth. The ganglion does not include all the fibres of the
nerve ; the fasciculus, which is sent from the spinal accessory to join
the vagus, is the part not involved in the ganglionic substance. It
communicates with the hypoglossal, the spinal, and the sympathetic
nerves.

The pneumo-gastric nerve descends in the neck, between and concealed
by the internal jugular vein and the internal carotid artery, and after-
wards similarly between that vein and the common carotid artery, being
enclosed along with them in the sheath of the vessels. As they enter
the thorax, the nerves of the right and left side present some points of
difference, of which the following are the most important.

On the right side the nerve crosses over the first part of the right sub-
clavian artery, at the root of the neck, and its recurrent laryngeal
branch turns backwards and upwards round that vessel. The nerve
then enters the thorax behind the right innominate vein, and descends
on the side of the trachea to the back of the root of the lung, where it
spreads out in the posterior pulmonary plexus. It emerges from this
plexus in the form of two cords, which are directed to the cesophagus,
and by their union and subdivision on it form, with similar branches of
the left side, the cesophageal plexus. Near the lower part of the thorax,
the oranches of the nerve, which have thus interchanged fibres with the
nerve of the left side, are gathered again into a single trunk, which,
descending on the back of the cesophagus, is spread out on the posterior
or inferior surface of the stomach.

On the left side the pneumo-gastric nerve, entering the thorax between
the left carotid and subclavian arteries and behind the left innominate
vein, lies further forwards than the right nerve, and crosses over the arch
of the aorta, while its recurrent laryngeal branch turns up behind the
arch. It then passes behind the root of the left lung, and, emerging
from the posterior pulmonary plexus, is distributed like its fellow on the
cesophagus. Inferiorly, it forms a single trunk in front of the ceso-
phagus, and is spread out on the anterior or superior surface of the
stomach.

There are various circumstances in the distribution of the pneumo-gastric
nerves which at first sight appear anomalous, but which are explained by re-
ference to the process of development. The recurrent direction of the inferior
laryngeal branches in all probability arises from the extreme shortness or rather
absence of the neck in the embryo at first, and from the branchial arterial arches
having originally occupied a position at,a higher level than the parts in which
those branches are ultimately distributed, and having dragged them down as it

560 THE CRANIAL NERVES.

were in the descent of the heart from the neck to the thorax. The recurrent
direction may therefore be accepted as evidence of the development of those
nerves before the occurrence of that descent. The passage of one recurrent
laryngeal nerve round the subclavian artery, and of the other round the aorta,
arises from the originally symmetrical disposition in which the innominate and
subclavian arteries on the right side and the arch of the aorta on the left are
derived from corresponding arches. The supply of the back of the stomach by
the right pneumo-gastric nerve, and of the front by the left nerve, is connected
with the originally symmetrical condition of the alimentary canal, and the
turning over of the stomach on its right side in its subsequent growth.

BRANCHES.—Some of its branches serve to connect the pneumo-
gastric with other nerves, and others are distributed to the muscular
substance or the mucous lining of the organs which the nerve supplies.
The principal connecting branches of this nerve are derived from the
ganglia. In the different stages of its course branches are supplied to
various organs as follows. In the jugular foramen, a branch is given to
the ear ; inthe neck, branches are furnished successively to the pharynx,
the larynx, and the heart ; and in the thorax, additional branches are
distributed to the heart, as well as to the lungs and the cesophagus.
Terminal branches in the abdomen are distributed to the stomach,
liver, and other organs.

Connecting branches and auricular branch. — Connections between the upper
ganglion of the vagus nerve and the spinal accessory, glosso-pharyngeal and sympa-
thetic nerves.—The connection with the spinal accessory is effected by one or two
filaments. The filament to the petrous ganglion of the glosso-pharyngeal is
directed transversely ; it is not always present. The communication with the
sympathetic is established by means of the ascending branch of the upper cervical
ganglion.

The auricular branch is continued to the outer ear. Arising from the ganglion
of the root, this branch is joined by a filament from the glosso-pharyngeal nerve,
and then turns backwards along the outer boundary of the jugular foramen to
an opening near the styloid process. Next, it traverses the substance of the
temporal bone, crosses the aqueduct of Fallopius about two lines from the lower
end, and, reaching the surface between the mastoid process and the external
auditory meatus, is distributed to the integument of the back of the ear. On
the surface it joins with a twig from the posterior auricular branch of the facial
nerves.

Connections of the second ganglion with the hypoglossal, sympathetic, and spinal
nerves—This ganglion is connected by filaments with the trunk of the hypo-
glossal, with the upper cervical ganglion of the sympathetic, and with the loop
formed between the first two cervical nerves.

Pharyngeal branch.—The pharyngeal branch arises from the upper
part of the ganglion of the trunk of the nerve. In its progress in-
wards to the pharynx this nerve crosses in some cases over, in others
under, the internal carotid artery ; and it divides into branches, which,
conjointly with others derived from the glosso-pharyngeal, the superior
laryngeal, and the sympathetic nerves, form a plexus (pharyngeal) be-
hind the middle constrictor of the pharynx. From the plexus branches
are given to the muscular structure, and to the mucous membrane of the
pharynx. As the pharyngeal nerve crosses the carotid artery, it joins
filaments which the glosso-pharyngeal distributes on the same vessel.—
There is sometimes a second pharyngeal branch.

Superior pharyngeal branch.—This nerve springs from the middle
of the ganglion of the trunk of the pneumo-gastric nerve. It is directed

THE PNEUMOGASTRIC NERVE. 561

inwards to the larynx beneath the internal carotid artery, and divides
beneath that vessel into two branches, distinguished as external and in-
ternal laryngeal, both of which ramify in the structures of the larynx.

The external laryngeal branch, the smaller of the two divisions, gives
backwards, at the side of the pharynx, filaments to the pharyngeal
plexus and the lower constrictor muscle ; and it is finally prolonged be-
neath the muscles on the side of the larynx to the crico-thyroid muscle
in which it ends, {nm the neck this branch joins the upper cardiac
nerve of the sympathetic.

The internal laryngeal branch is continued to the interval between the
hyoid bone and the thyroid cartilage, where it perforates the thyro-hyoid
membrane with the laryngeal branch of the superior thyroid artery, and
distributes filaments to the mucous membrane: some of these are di-
rected upwards in the aryteno-epiglottidean fold of mucous membrane
to the base of the tongue, the epiglottis, and the epiglottidean glands ;
while others are reflected downwards in the lining membrane of the
larynx, extending to the corda vocalis, on the inner side of the laryngeal
pouch. A slender communicating branch to the recurrent laryngeal
nerve descends beneath the lateral part of the thyroid cartilage. A
branch enters the arytenoid muscle, some filaments of which seem to
end in the muscle, while others proceed through it to the mucous
membrane.

Recurrent laryngeal branch.—The recurrent or inferior laryngeal
branch of the vagus nerve, as the name expresses, has a reflex course to
the larynx.

The nerve on the riyht side arises at the top of the thorax, winds
round the subclavian artery, and passes beneath the common carotid
and inferior thyroid arteries in its course towards the trachea. On the
left side the recurrent nerve is bent round, below and behind the arch
of the aorta, immediately beyond the point where the obliterated ductus
arteriosus is connected with the arch, and is thence continued upwards
to the trachea.

Each nerve in its course to the larynx is placed between the trachea
and cesophagus, supplying branches to both tubes ; and each, whilemaking
its turn round the artery, gives nerves to the deep cardiac plexus. At
the lower part of the cricoid cartilage the recurrent nerve distributes
branches to supply all the special muscles of the larynx, except the crico-
thyroid muscle, which is supplied from the upper laryngeal nerve. It
likewise gives a few offsets to the mucous membrane, and a single com-
municating filament which joins the long branch of the upper laryngeal
nerve beneath the side of the thyroid cartilage.

Cardiac branches.—Branches to the heart are given off by the
pneumo-gastric nerve both in the neck and in the thorax.

The cervical cardiac branches arise at both the upper and the lower
part of the neck. The upper branches are small, and join the cardiac
nerves of the sympathetic. The dower, a single branch, arises as the
pneumo-gastric nerve is about to enter the chest. On the right side
this branch lies by the side of the innominate artery, and joins one of
the cardiac nerves destined for the deep cardiac plexus ; it gives some
filaments to the coats of the aorta. The branch of the left side
crosses the arch of the aorta, and ends in the superficial cardiac plexus.

The thoracic cardiac branches of the right side leave the trunk of the

pheumo-gastric as this nerve lies by the side of the trachea, and some
you. I, 00

THE PNEUMOGASTRIC NERVE. 563

Vig. 349.—View or tHe DistriBuTion AND CONNECTIONS OF THE PNEUMOGASTRIC AND
Sympatuetic Nerves oN THE Riau Sipe (after Hirschfeld and Leveillé). 2

a, lachrymal gland ; 6, sublingual gland; ¢c, submaxillary gland and facial artery ,
d, thyroid gland, pulled forwards by a hook; e, trachea, below which is the right
bronchus cut across; f, the gullet ; g, the stomach, divided near the pylorus; 7, trans-
verse colon, with some folds of the intestines below.

A, heart, slightly turned aside to show the cardiac plexus, &c. ; B, aortic arch, drawn
forward by a hook; C, innominate artery ; D, subclavian artery, of which a portion has
been removed to show the sympathetic ganglia; E, inferior thyroid artery ; F, a divided
part of the external carotid artery, upon which runs a nervous plexus; G, internal
carotid emerging from its canal superiorly ; H, thoracic aorta ; K, intercostal vein ; L,
pulmonary trunk, the right branch cut ; M, superior vena cava ; O, intercostal artery.

1, ciliary nerves of the eyeball ; 2, branch of the oculo-motor to the inferior oblique
muscle, connected with the ophthalmic ganglion ; 3, 3, 3, the three principal divisions of
the trifacial nerve ; 4, ophthalmic ganglion ; 5, spheno-palatine ; 6, otic ; 7, submaxillary ;
8, sublingual ; 9, sixth nerve; 10, facial in its canal, uniting with the spheno-palatine
and otic ganglia; 11, glosso-pharyngeal ; 12, right pneumogastric ; 13, left pneumo-
gastric spreading on the anterior surface of the stomach ; 14, spinal accessory ; 15, hypo-
glossal ; 16, lower nerve of the cervical plexus; 17, middle nerve of the brachial
plexus ; 18, intercostal nerves ; 21, superior cervical ganghon of the sympathetic, con-
nected with, 22, the tympanic nerve of Jacobson ; 23, carotid branch of the Vidian nerve ;
24, cavernous plexus , 25, ophthalmic twig; 26, filament to the pituitary gland ; 27,
union with the upper cervical nerves ; 28, points to the pneumogastric nerve, close to
the pharyngeal and carotid branches ; 29, points to the superior laryngeal nerve, close to
the pharyngeal and inter-carotid plexuses , 30, laryngeal branch joining the laryngeal
plexus ; 31, great sympathetic nerve ; 32, superior cardiac nerve; 33, middle cervical
ganglion ; 34, twig connecting the ganglion with, 35, the recurrent ; 36, middle cardiac
nerve ; 37, great sympathetic nerve , 38, inferior cervical ganglion; below 37, branches
from the ganglion, passing round the subclavian and vertebral arteries ; 39, the line from
this number crosses the nerves proceeding from the brachial plexus ; 40, sympathetic
twigs surrounding the axillary artery ; 41, branch of union with the first intercostal
nerve ; the line from the letter e, pointing to the trachea, crosses the superior, middle,
and inferior cardiac nerves ; 42, cardiac plexus and ganglion; 43, 44, right and left
coronary plexuses ; 45, 46, thoracic portion of the great sympathetic nerve and ganglia
showing their connections with the intercostal nerves; 47, great splanchnic nerve; 48,
semilunar ganglion ; 49, lesser splanchnic ; 50, solar plexus ; 51, union with the pneumo-
gastric nerve ; 52, diaphragmatic plexus and ganglion , 53, coronary plexus ; 54, hepatic ;
55, splenic ; 56, superior mesenteric , 57, renal plexus.

are also derived from the first part of the recurrent branch: they pass
mwards on the air-tube, and end in the deep cardiac plexus. The cor-
responding branches of the left side come from the left recurrent laryn-
geal nerve.

Pulmonary branches.—T'wo sets of pulmonary branches are dis-
tributed from the pneumogastric nerve to the lung; and they reach
the root of the lung, one on its fore part, the other on its posterior as-
pect. The anterior pulmonary nerves, two or three in number, are of
small size. They join with filaments of the sympathetic ramifying on
the pulmonary artery, and with these nerves constitute the anterior
pulmonary plexus. Behind the root of the lung the pneumogastric
nerve becomes flattened, and gives several branches of much larger size
than the anterior branches, which, with filaments derived from the
second, third, and fourth thoracic ganglia of the sympathetic, form the
posterior pulmonary plexus. Offsets from this plexus extend along the
ramifications of the air-tube through the substance of the lung.

Csophageal branches.—The cesophagus within the thorax receives
branches from the pneumogastric nerves, both above and below the
pulmonary branches. The lower brariches are the larger, and are de-
rived from the esophageal plexus, formed by connecting cords between

002

564 THE CRANIAL NERVES.

the nerves of the right and left sides, while they lie in contact with the
cesophagus.

Gastric branches.—The branches distributed to the stomach
(gastric nerves) are the terminal branches of both pneumogastric nerves.
The nerve of the left side, on arriving in front of the esophagus, oppo-
site the cardiac orifice of the stomach, divides into many branches: the
largest of these extend over the fore part of the stomach ; others lie
alone its small curvature, and unite with branches of the right nerve
and the sympathetic ; and some filaments are continued between the
layers of the small omentum to the hepatic plexus. The right pneumo-
gastric nerve descends on the back of the gullet to the stomach, and
distributes branches to the posterior surface of the organ: a part of
this nerve is continued from the stomach to the left side of the cceliac
plexus, and to the splenic plexus of the sympathetic.

Varieties. —The pneumogastric nerve of the right side has been found in front
of the sheath of the great cervical vessels (Quain). In several instances the
origin of the descendens noni has been transferred to the trunk of the pneumo-
gastric, Turner, who has recorded such cases, mentions also one in which the
entire trunk of the hypoglossal nerve was intimately connected with the pneumo-
gastric as low as the posterior belly of the digastric muscle. The superior
laryngeal nerve has frequently been seen to give branches to the thyro-hyoid
and sterno-hyoid muscles (Meckel, Reid, Cloquet, Krause). The recurrent
laryngeal in rare cases supphes the crico-thyroid muscle (Reid). This nerve also,
in those cases in which the right subclavian artery arises from the left side of the
aortic arch, passes directly inwards to the larynx in the neck, and is not hooked
downwards towards the thorax by the subclavian. This abnormality is explained
developmentally by the origin of the subclavian from the right aortic root
posteriorly, and by the closure of the fourth branchial arch, as well as of the
fifth, upon the right side.

Summary.—The pneumogastric nerves supply branches to the upper
part of the alimentary canal, viz., the pharynx, cesophagus, and stomach
with the liver and spleen ; ; and to the respiratory passages, namely, the

larynx, trachea, and its divisions in the lungs. These nerves give
branches likewise to the heart and ereat vessels “by means of their com-
munication with the cardiac plexus. Each pneumogastric nerve is
connected with the following cranial nerves—the spinal accessory,
glosso-pharyngeal, facial, and hypoglossal: also, with some spinal
nerves ; and with the sympathetic in the neck, thorax, and abdomen.

III. SPINAL ACCESSORY NERVE.

The spinal nerve accessory to the vagus, or, as it is shortly named,
the spinal accessory nerve, consists of two parts : one (accessory) joins
the trunk of the pneumogastric ; the other (spimal) ends in branches
to the sterno-mastoid and trapezius muscles.

Surface attachment.—The accessory nerve arises by a series of
roots, the upper of which are attached to the side of the medulla below
those of the pneumogastric, while the remainder arise from the lateral

column of the cervical portion of the cord as low down as the sixth or
seventh pair of nerves. The lowest spinal roots are attached to the
middle of the lateral column ; the highest spinal roots arise close to the
posterior nerve roots.

Deep origin.—The upper roots pass inwards to a nucleus which
lies, on each side, at the back of and close to the central canal. It
contains large nerve-cells, and is continuous, above, with the column of

SPINAL ACCESSORY AND HYPOGLOSSAL NERVES. 565

cells giving origin to the pneumogastric nerve. The lower or spinal
roots pass through the lateral column of the cord, and enter the grey
substance midway between the anterior and posterior cornua. They
then curve forwards into the anterior horn, and are believed to be
connected with its large nerve-cells, especially with the outer group.

Course and distribution.—The infernal or accessory part, the
smaller of the two, joins in the foramen of exit the ganglion on the
root of the pneumogastric, by two or three filaments ; and having
passed from the skull, blends with the trunk of the pneumogastric
beyond its second ganglion, as already said.

It is stated by Bendz that a filament is given from the spinal accessory to the
pharyngeal nerve above the place of junction with the pneumogastric, and the
fibrils of the same nerve have been traced into each of the muscular offsets of the
pneumogastric nerve. (Bendz, “ Tract.de connexu inter nery. vag. et acces.” 1836.)

The external portion of the nerve communicates with the accessory
part in the foramen jugulare. After issuing from the foramen, the
nerve is directed backwards in front of the internal jugular vein, and
perforates the sterno-mastoid muscle, supplying this with branches, and
joining amongst the fleshy fibres with branches of the cervical plexus.
Descending in the next place across the neck behind the sterno-mastoid,
the nerve passes beneath the trapezius muscle. Here it forms a kind of
plexus with branches of the third and fourth cervical nerves, and dis-
tributes filaments to the trapezius, which extend nearly to the lower
edge of the muscle.

Varieties.—The spinal accessory nerve frequently passes behind the internal
jugular vein. It has also been found to pass behind the sterno-mastoid muscle
without piercing it (Turner, Nat. Hist. Review, 1864).

NINTH PAIR OF NERVES.

The hypoglossal or ninth cranial nerve is the motor nerve of the
tongue, and in part of some of the muscles of the neck.

Surface attachment.—The nerve arises, by a series of fine roots,
from the furrow between the anterior pyramid of the medulla and the
olivary body.

Deep origin.—The bundles of fibres pass backwards, through the
inner part of the olivary body, to reach their nucleus, a column of
large branching nerye-cells lying in front of and close to the central
canal, as low as the decussation of the pyramids. Above, where the
canal opens into the floor of the fourth ventricle, the nucleus comes to
the surface, causing a prominence close to the middle line, a little
above the point of the calamus scriptorius.

Course and distribution.—The filaments by which this nerve arises
from the medulla oblongata are collected into two bundles, which con-
verge to the anterior condylar foramen of the occipital bone. Each
bundle of filaments perforates the dura mater separately within the
foramen, and the two are joined after they have passed through it.

After leaving the cranium, this nerve descends almost vertically to
the lower border of the digastric muscle, where, changing its course, it
is directed forwards above the hyoid bone to the under part of the
tongue. It lies at first very deeply with the vagus nerve, to which it is
connected ; but passing between the, internal carotid artery and the
jugular vein, it curves forwards round the occipital artery, and then

566 THE CRANIAL NERVES.

crosses over the external carotid below the digastric muscle. Above
the hyoid bone it is crossed by the lower part of the stylo-hyoid muscle
and posterior belly of the digastric, and rests on the hyo-glossus muscle.
At the anterior border of the hyo-glossus it is connected with the gusta-
tory nerve, and is continued in the fibres of the genio-hyo-glossus
muscle beneath the tongue to the tip, distributing branches upwards to
the muscular substance.

The principal BRANCHES of this nerve are distributed to the muscles
ascending to the larynx and hyoid bone, and to those of the tongue ; a
few serve to connect it with some of the neighbouring nerves.

Fig. 850.—View or tur DistRIBUTION OF THE SpiInAL AccEssoRY AND HypogLossaL
Nerves (from Sappey after Hirschfeld and Leveillé). 4

1, lingual nerve ; 2, pneumogastric nerve; 3, superior laryngeal (represented too
large) ; 4, external laryngeal branch ; 5, spinal accessory ; 6, second cervical ; 7, third ;
8, fourth ; 9, origin of the phrenic nerve ; 10, origin of the branch to the subclavius
muscle ; 11, anterior thoracic nerves ; 12, hypoglossal nerve ; 13, its descending branch ;
14, communicating branch from the cervical nerves ; 15, 16, 18, 19, descending branches
from the plexiform union of these nerves to the sterno-hyoid, sterno-thyroid, and omo-
hyoid muscles ; 17, branch from the descendens noni to the upper belly of the omo-hyoid
muscle ; 20, branch from the hypoglossal nerve to the thyro-hyoid muscle ; 21, communi-
cating twigs from the hypoglossal to the lingual nerve ; 22, terminal distribution of the
hypoglossal to the muscles of the tongue.

THE HYPOGLOSSAL NERVE. 567

Connecting branches.—Connection mith the pneumogastrie—Close to the
skull the hypoglossal nerve is connected with the second ganglion of the pneumo-
gastric by separate filaments, or in some instances the two nerves are united so
as to form one mass.

Union with the sympathetic and first two spinal nerves.—Opposite the first
cervical vertebra the nerve communicates by several twigs with the upper cervical
ganglion of the sympathetic, and with the loop uniting the first two spinal
nerves in front of the atlas.

Descending branch of the ninth nerve.—This branch (r. de-
scendens noni) leaves the ninth nerve where this turns round the occi-
pital artery, or, sometimes, higher up. It passes downwards on the sur-
face of the sheath of the carotid vessels, gradually crossing from the
outer to the inner side, gives a branch to the anterior belly of the omo-
hyoid muscle, and joins about the middle of the neck in a loop with one
or two branches from the second and third cervical nerves, forming the
ansa hypoglossi. The concavity of this loop is turned upwards ; and
the connection between the nerves is effected by means of two or more
interlacing filaments, which enclose an irregularly shaped space. From
this interlacement of the nerves, filaments are continued backwards to
the posterior belly of the omo-hyoid, and downwards to the sterno-hyoid
and sterno-thyroid muscles. Occasionally a filament is continued to
the chest, where it joins the cardiac and phrenic nerves.

Muscular branches.—The branch to the thyro-hyoid muscle is a
separate twig given off from the hypoglossal nerve as it approaches the
hyoid bone.

The nerve supplies branches to the hyo-glossus, genio-hyoid,
and genio-hyo-glossus muscles as it becomes contiguous to each,
and, when arrived close to the middle of the tongue in company with
the ranine artery, gives off several long slender branches, which pass
upwards into the substance of the organ. Some filaments join with
others proceeding from the gustatory nerve.

Varieties.—In animals the ninth nerve not unfrequently possesses a posterior
root furnished with a ganglion, in the same manner as that of a spinal nerve.

It is not uncommon to find the descending branch of the ninth nerve within
the sheath of the large cervical vessels and in such cases it is placed either over
or under the vein. This nerve in some cases appears to be derived either alto-
gether from the pneumogastric, or from both the pneumo-gastric and hypo-
glossal nerves. There is every reason, however, to believe that these varieties in
origin are only apparent, arising from the temporary adhesion of the filaments
of this branch to those of -the pneumogastric. It is probable, moreover, that
the descendens noni has little if any real origin from the hypoglossal nerve :
Luschka states, as the result of numerous researches on the human subject,
that the descendens noni usually contains no filaments from the hypoglossal,
but is a branch from the first and second cervical, temporarily associated with
the ninth nerve ; and this quite sgrees with the circumstance that in some
animals the nerves supplied to those muscles to which the descendens noni of the
human subject is distributed come from the cervical plexus.

A branch is described as uniting with its fellow of the opposite side in the
substance of the genio-hyoid muscle, or between it and the genio-glossus. This
loop, as also the ansa hypoglossi, is recommended by Hyrtl as a particularly
favourable example for the observation of nerve-fibres returning to the nervous
centres without distribution, to which he gives the name of “nerves without
ends.” (‘‘ Nat. Hist. Review,” Jan. 1862.) It was observed by Cruveilhier that
in the ansa hypoglossi an interchange of fibres takes place, so that a filament of
the cervical spinal nerve is directed upwards along the branch of the hypoglossal,
and vice versa

568 THE SPINAL NERVES.

Fig. 851.—DracRAMMATIC OUTLINE OF THE Roots
AND Frrst Parr oF THE Spinat NERVES, 'T0-
GETHER WITH THE SYMPATHETIC TRUNK OF ONE
Sipe, (A. 1!) 2

The view is taken from before. In the upper
part of the figure the pons Varolii and medulla
oblongata are represented, and from V to IX,
the roots of the several cranial nerves from the
trifacial to the hypoglossal are indicated. On
the left side C 1 is placed opposite the first cer-
vical or suboccipital nerve ; and the numbers 2 to
8 following below indicate the corresponding cer-
vical nerves ; Br, indicates the brachial plexus ;
D 1, is placed opposite the intercostal part of the
first dorsal nerve, and the numbers 2 to 12 follow-
ing mark the corresponding dorsal nerves; L 1,
the first lumbar nerve, and the numbers 2 to 5,
following the remaining lumbar nerves ; Cr, the
anterior crural, and 0, the obturator nerve; S 1,
the first sacral, and the following numbers 2 to 5,
the remaining sacral nerves; 6, the coccygeal
nerve ; Sc, the great sciatic nerve; +, +, the
filum terminale of the cord.

On the right side of the figure the following
letters indicate parts of the sympathetic nerves ;
viz., a, the superior cervical ganglion communi-
cating with the upper cervical spinal nerves and
continued below in the great sympathetic cord ;
b, the middle cervical ganglion; c, d, the
Jower cervical ganglion united with the first
dorsal ; a’, the eleventh dorsal ganglion ; from
the fifth to the ninth dorsal ganglion the origins
of the great splanchnic nerve are shown ; J, the
lowest dorsal or upper lumbar ganglion; ss, the
upper sacral ganglion. In the whole extent of the
sympathetic cord, the twigs of union with the
spinal nerves are shown.

i
mY:
rn
ie

EP

SummMAry.—The hypoglossal nerve
supplies, either alone or in union with
branches of the spinal nerves, all the
muscles connected with the os hyoides,
including those of the tongue, with the
exception of the digastric, stylo-hyoid,
mylo-hyoid and the middle constrictor
of the pharynx. It also supplies the
sterno-thyroid muscle.

It is connected with the following
nerves, viz., pneumo-gastric, lingual,
three upper cervical nerves, and the
sympathetic.

a

fo

B. SPINAL NERVES.

The spinal nerves are characterised
by their origin from the spinal cord,
and their direct transmission outwards
from the spinal canal in the intervals
between the vertebra. Taken together,
these nerves consist of thirty-one pairs ;

ROOTS OF THE SPINAL NERVES. 569

and, according to the region in which they issue from the spinal canal,
they are named cervical, dorsal, lumbar, sacral, and coccygeal.

By universal'usage each pair of nerves in the dorsal, lumbar, and sacral
regions is named in correspondence with the vertebra beneath which it
emerges. Of the remaining eight pairs of nerves between the cranium
and the first dorsal:nerve, the uppermost is placed above the atlas, and
the second and following nerves below the seven cervical vertebre in
succession. These eight pairs are usually reckoned as eight cervical
nerves, but the first is also distinguished by the name of sub-occipital
nerve. ‘The nerves of the thirty-first pair emerge from the lower end
of the sacral canal, pass below the first vertebra of the coccyx, and are
named coccygeal.

Although the plan of counting eight cervical nerves is continued in this work
for the sake of convenience, it being that which is most frequently followed, it is
by no means intended to represent this method as the best or as scientifically cor-
rect. The plan of Willis, who reckoned the sub-occipital as a cranial nerve, had
at least the advantage that it made the numbers of the remaining seven cer-
vical nerves correspond each with the vertebra beneath which it emerged, as do
the dorsal, lumbar and sacral nerves; and if the sub-occipital nerve, while
recognised as the first spinal nerve, were to be kept distinct from the seven
which succeed, a more uniform system of nomenclature would be arrived at than
that which is at present in most common use.

Varieties.—Sometimes an additional coccygeal nerve exists. Among seven
cases which appear to have been examined with great care, Professor Schlemm
C‘ Observat. Neurologic,” Berolini, 1834) found two coccygeal nerves on each
side in one instance. and on one side in another case. In all the rest there was
only a single coccygeal nerve on each side.

THE ROOTS OF THE SPINAL NERVES.

Each spinal nerve springs from the spinal cord by two roots which
approach one another as ‘they quit the spmal canal, and join in the
corresponding intervertebral foramen into a single cord ; and each cord
so formed separates immediately into two divisions, one of which is
destined for parts in front of the spine, the others for parts behind it.

Structure.—The posterior roots of the nerves are distinguished from
the anterior roots by their greater size, as well as by the greater thick-
ness of the fasciculi of which they are composed. Lach spinal nerve
is furnished with a ganglion situated on the posterior root: but the
first cervical or sub-occipital nerve is in some cases without one. The
size of the ganglion is in proportion to that of the nerve on which
it is formed.

The ganglia are in general placed in the intervertebral foramina,
immediately beyond the points at which the roots perforate the dura
mater lining the spinal canal. The first and second cervical nerves, how-
ever, which leave the spinal canal, over the lamine of the vertebrae, have
their ganglia opposite those parts. The ganglia of the sacral nerves are
contained in the spinal canal, that of the last nerve being occasionally
at some distance from the point at which the nerve issues. The gan-
glion of the coccygeal nerve is placed within the canal in the sac of
dura mater, and at a variable distance from the origin of the nerve.

The fibres of the posterior root of the nerve divide into two bundles
as they approach the ganglion, and the inner extremity of the oval-
shaped ganglion is sometimes bilobate, the lobes corresponding to the
two bundles of fibres.

570 THE SPINAL NERVES.

The anterior roots of the spinal nerves are, as will be inferred from
what has been already stated, the smaller of the two ; they are devoid
of ganglionic enlargement, and their fibres are collected into two
bundles near the intervertebral ganglion, as in the posterior root.

Size.—The roots of the upper cervical nerves are smaller than those
of the lower nerves, the first being much the smallest. The posterior
roots of these nerves exceed the anterior in size more than in the other
spinal nerves, and they are likewise composed of fasciculi which are
considerably larger than those of the anterior roots.

Fig. 352. — DIFFERENT
VIEWS OF A PORTION OF
THE SPINAL CORD FROM
THE CERVICAL REGION
WITH THE Roots oF
THE Nerves. Slightly
enlarged. (A. T.)

In A, the anterior sur-
face of the specimen is
shown, the anterior nerve-
root of the right side
being divided; in B, a
view of the right side is
given; in C, the upper
surface is shown ; in D,
the nerve-roots and gan-
glion are shown from
below. 1, the anterior
median fissure; 2, pos-
terior median fissure; 3,
anterior lateral depres-
sion, over which the ante-
rior nerve-roots are seen
to spread; 4, posterior
lateral groove, into which
the posterior roots are
seen to sink ; 5, anterior
roots passing the ganglion ;
5’, in A. the anterior root
divided ; 6, the posterior roots, the tibres of which enter the ganglion, 6’ ; 7, the united
or compound nerve; 7’, the posterior primary branch seen in A and D to be derived in
part from the anterior and in part from the posterior root.

The roots of the dorsal nerves, exception being made of the first, which
resembles the lowest cervical nerves and is associated with them ina
part of its distribution, are of small size, and vary but slightly, or not
at all, from the second to the last. The fasciculi of both roots are
thinly strewed over the spinal cord, and are slender, those of the
posterior exceeding in thickness those of the anterior root in only a
small degree.

The roots of the lower lwmbar, and of the upper sacral nerves, are the
largest of all the spinal nerves ; those of the lowest sacral and of the
coceygeal nerve are, on the other hand, the slenderest. All these
nerves are crowded together round the lower end of the cord. Of
these nerves the anterior roots are the smaller, but the disproportion
between the anterior and posterior roots is not so great as in the
cervical nerves.

Length of the nerves in the spinal canal.—The place at
which the roots of the upper cervical nerves are connected with the

POSTERIOR DIVISIONS OF SPINAL NERVES. 571

spinal cord being nearly opposite the foramina by which they respec-
tively leave the canal, these roots are comparatively short. But the
distance between the two points referred to is gradually augmented
from nerve to nerve downwards, so that the place of origin of the lower
cervical nerves is the breadth of at least one vertebra, and that of the
lower dorsal nerves about the breadth of two vertebree above the fora-
mina by which they respectively emerge from the canal. Moreover, as
the spinal cord extends no farther than the first lumbar vertebra, the
length of the roots of the lumbar, sacral and coccygeal nerves increases
rapidly from nerve to nerve, and in each case may be estimated by the
distance of the foramen of exit from the extremity of the cord. Owing
to their length, and the appearance they present in connection with the
spinal cord, the aggregation of the roots of the nerves last referred to
has been named the ‘‘ cauda equina.’

The direction the roots take within the canal requires brief notice.
The first cervical nerve is directed horizontally outwards. The roots
of the lower cervical and dorsal nerves at fiyst descend over the spinal
cord, held in contact with it by the arachnoid, till they arrive opposite
the several intervertebral foramina, where they are directed horizontally
outwards. The nerves of the cauda equina run in the direction of the
spinal canal.

Division of the nerves.—The two roots of each of the spinal
nerves unite immediately beyond the ganglion, and the trunk thus
formed separates, as already mentioned, into two divisions, an anterior
and a posterior, which are called primary branches or divisions.

In the detailed description of the spinal nerves which follows, we shall
begin with their posterior primary divisions, calling attention first to
certain characters common to the whole of them, and afterwards stating
separately the arrangement peculiar to each group of nerves (cervical,
dorsal, &c.)

POSTERIOR PRIMARY DIVISIONS OF THE SPINAL
NERVES.

‘The posterior divisions of the spinal nerves are, with few exceptions,
smaller than those given to the fore part of the body. Springing from
the trunk which results from the union of the roots of the nerve in the
intervertebral foramen, or frequently by separate fasciculi from each of
the roots, each turns backwards at once, and soon divides into two
parts, distinguished as external and internal, distributed to the muscles
and the integument behind the spine. The first cervical, the fourth and
fifth sacral and the coccygeal nerve are the only nerves the posterior
divisions of which do not separate into external and internal branches.

THe Sus-occrpiraAL NERvE.—-The posterior division of the sub-occi-
pital nerve, which is the larger of the two primary divisions, emerging
over the arch of the atlas, between this and the vertebral artery, enters
the space bounded by the larger rectus and the two oblique muscles,
and divides into branches for the surrounding muscles.

a. One branch descends to the lower oblique muscle and gives a filament,
through or over the fibres of that muscle, to join the second cervical nerve.

b. Another ascends over the larger rectus muscle, supplying it and the smaller
rectus.

c. A third enters the upper oblique muscle.

d. A fourth sinks into the complexus, where that muscle covers the nerve and
its branches.

572 THE SPINAL NERVES.

Fig. 353.

Fig. 353.—Suprrrictan anp Drrp Disrrisurion or rar Postertor Primary Divisiors
OF THE SprnaL Nerves (after Hirschfeld and Leveillé). +

On the left side the cutaneous branches are represented as lying upon the superficial
layer of muscles ; on the right side, the superficial muscles having been removed, the

POSTERIOR DIVISIONS OF SPINAL NERVES. 573

splenius and complexus have been divided in the neck, and the erector spine separated
and partially removed in the back, so as to expose the deep issue of the nerves.

a, a, lesser occipital nerve from the cervical plexus ; 1, external muscular branches of
the first cervical nerve and union by a loop with the second ; 2, placed on the rectus
capitis posticus major, marks the great occipital nerve passing round the short muscles
and piercing the complexus ; the external branch is seen to the outside ; 2’, cranial dis-
tribution of the great occipital ; 5, external branth of the posterior primary division of
the third nerve; 3’, its internal branch, or third occipital nerve; 4’, 5’, 6, 7’, 8,
internal branches of the several corresponding nerves on the left side ; the external
branches of these nerves proceding to muscles are displayed on the right side: d 1 to
d 6, and thence to d 12, external muscular branches of the posterior primary divisions of
the twelve dorsal nerves on the right side ; d 1’, to d 6’, the internal cutaneous branches
of the six upper dorsal nerves on the left side ; d 7’ to d 12’, cutaneous branches of the
six lower dorsal nerves from the external branches ; J, 7, external branches of the pos-
terior primary branches of several lumbar nerves on the right side piercing the muscles,
the lower descending over the gluteal region ; U’, U', the same more superficially on the left
side ; s, s, on the right side, the issue and union by loops of the posterior primary
divisions of four sacral nerves ; s’, s’, some of these distributed to the skin on the left side.

A cutancous branch is occasionally given to the back of the head; it accom-
panies the occipital artery, and is connected beneath the integument with the
great and small occipital nerves.

CervicaL Nerves (excepting the sub-occipital). — The external
branches ive only muscular offsets, and are distributed to the splenius
and the slender muscles prolonged to the neck from the erector spine,
viz., the cervicalis ascendens, and the transversalis colli with the
trachelo-mastoid. That of the second nerve is the largest of the
series of external branches, and is often united to the corresponding
branch of the third; it supplies the complexus muscle which covers
it, and ends in the splenius and trachelo-mastoid muscles.

The internal branches, larger than the external, are differently
disposed at the upper and the lower parts of the neck. That of the
second cervical nerve is named, from its size and destination, the great
occipital, and requires separate notice. The rest are directed inwards
to the spinous processes of the vertebrae. Those derived from the third,
fourth, and fifth nerves pass over the semispinalis and beneath the
complexus muscle, and, having reached the spines of the vertebre,
turn transversely outwards and are distributed in the integument over
the trapezius muscle. From the cutaneous branch of the third nerve a
branch passes upwards to the integument on the lower part of the
occiput, lying at the inner side of the great occipital nerve, and is some-
times called third occipital nerve.

Between the inner branches of the first three cervical nerves, beneath the

complexus, there are frequently communicating fasciculi; and this communica-
tion Cruveilhier has designated as “ the posterior cervical plexus.’

The internal branches from the lowest three cervical nerves are placed
beneath the semispinalis muscle, and end in the muscular structure,
without furmshing (except occasionally the sixth) any offset to the skin.
These three nerves are the smallest of the series.

The great occipital nerve is directed wpwards on the lower oblique
muscle, and is transmitted to the surface through the complexus and
trapezius muscles, giving twigs to the complexus. Ascending with
the occipital artery, it divides into branches which radiate over the
occipital part of the occipito-frontalis muscle, some appearing to enter
the muscle, and others joining the smaller occipital nerve.

An auricular branch is sometimes supplied to the back of the ear by the great
occipital nerve.

574 THE SPINAL NERVES.

DorsaL Nerves.—The external branches increase in size from
above downwards. They are directed through or beneath the longis-
simus dorsi to the space between that muscle and the ilio-costalis and
accessorius ; they supply both those muscles, together with the small
muscles continued upwards from the erector spine to the neck, and
also the levatores costarum. The lower five or six nerves give cuta-
neous twigs, which are transmitted to the integument in a line with
the angles of the ribs.

The internal branches of the upper six dorsal nerves appear in the
interval between the multifidus spinz and the semispinalis dorsi ; they
supply those muscles, and become cutaneous by the side of the spinous
processes of the vertebre. The cutaneous branch of the second
nerve, and sometimes others, reach as far as the scapula. The internal
branches of the lower six dorsal nerves are placed between the multi-
fidus spinee and longissimus dorsi, and end in the multifidus without
giving branches to the integument. Where cutaneous nerves are sup-
plied by the internal branches, there are none from the external branches
of the same nerve, and vice versa.

Lumbar Nrerves.—The external branches enter the erector spine,
and give filaments to the intertransverse muscles. From the upper
three, cutaneous nerves are supplied ; and from the last, a fasciculus
descends to the corresponding branch of the first sacral nerve. The
cutaneous nerves given from the external branches of the first three
lumbar nerves, pierce the fleshy part of the ilio-costalis, and the
aponeurosis of the latissimus dorsi: they cross the iliac crest near the
edge of the erector spine, and terminate in the imtegument of the
gluteal region. One or more of the filaments may be traced as far as
the great trochanter of the femur.

The internal branches wind backwards in grooves close to the articu-
lar processes of the vertebrae, and sink into the mulifidus spme muscle.

SacrRAL NervES.—The posterior division of the nerves, except the
last, issue from the sacrum through its posterior foramina. The first
three are covered at their exit from the bone by the multifidus spime
muscle, and bifurcate like the posterior trunks of the other spinal
nerves ; but the remaining two, which continue below that muscle,
have a peculiar arrangement, and require separate examination.

The internal branches of the jirst three sacral nerves are small, and
are lost in the multifidus spine muscle.

The external branches of the same nerves are united with one
another, and with the last lumbar and fourth sacral nerves, so as to
form a series of anastomotic loops on the upper part of the sacrum.
These branches are then directed outwards to the cutaneous or posterior
surface of the great sacro-sciatic ligament, where, covered by the gluteus
maximus muscle, they form a second series of loops, and end in cuta-
neous nerves. These pierce the great gluteus muscle in the direction
of a line from the posterior iliac spine to the tip of the coceyx. They
are commonly three in number—one is near the innominate bone,
another opposite the sacrum, and the third about midway between the
other two. All are directed outwards over the great gluteal muscle.

In six dissections by Ellis this arrangement was found to be the most fre-
quent. The variations to which it is liable are these :—the first nerve may not

take part in the formation of the second series of loops, and the fourth may
be associated with them.

ANTERIOR DIVISIONS OF SPINAL NERVES. 575

The posterior divisions of the last two sacral nerves are smaller than
those above them, and are not divided into external and internal
branches. They are connected with each other by a loop on the back
of the sacrum, and the lowest is joined in a similar manner with the
coccygeal nerve ; one or two small filaments from these sacral nerves
are distributed behind the coccyx.

CoccyGEAL Nerve.—The posterior division of the coccygeal nerve is
very small, and separates from the anterior primary portion of the
nerve in the sacral canal. It is joined by a communicating filament
from the last sacral nerve, and ends in the fibrous structure covering
the posterior surface of the coccyx.

ANTERIOR PRIMARY DIVISIONS OF THE SPINAL
NERVES.

The anterior primary divisions of the spinal nerves are distributed
to the parts of the body situated in front of the vertebral column, in-
cluding the limbs. They are, for the most part, considerably larger
than the posterior divisions.

The anterior division of each spinal nerve is connected by one or
two slender filaments with the sympathetic. Those of the cervical,
lumbar, and sacral nerves form plexuses of various forms; but those of
the dorsal nerves remain for tlie most part separate from one another,

CERVICAL NERVES.

The anterior divisions of the four upper cervical nerves form the
cervical plexus. They appear at the side of the neck between the
scalenus medius and rectus anticus major muscles. They are each
connected by a communicating filament with the first cervical ganglion
of the sympathetic nerve, or with the cord connecting that ganglion
with the second.

The anterior divisions of the four lower cervical nerves, larger than
those of the upper four, appear between the scaleni muscles, and,
together with that of the first dorsal, go to form the brachial plexus.
They are each connected by a filament with one of the two lower cervical
ganglia of the sympathetic, or with the plexus on the vertebral artery.

The anterior divisions of the first and second nerves require a notice
separately from the description of the nerves of the cervical plexus.

SUB-OCCIPITAL NERVE.

The anterior primary division of the first nerve runs forwards in a
groove on the atlas, and bends downwards in front of the transverse
process of that vertebra to join the second nerve. In this course for-
wards it lies beneath the vertebral artery, and at the inner side of the
rectus lateralis muscle, to which it gives a branch. As it crosses the
foramen in the transverse process of the atlas, the nerve is joined by a
filament from the sympathetic; and from the loop which it makes in
front of the transverse process, branches are supplied to the two anterior
recti muscles. Short filaments connect this part of the nerve with the
pneumo-gastric, the hypoglossal, and the sympathetic nerves.

Valentin notices filaments distributed to the articulation of the occipital bone
with the atlas, and to the mastoid process of the temporal bone.
6

.

576 THE SPINAL NERVES.

SECOND CERVICAL NERVE.

The anterior division of the second cervical nerve, beginning between
the arches of the first two vertebra, is directed forwards between their
transverse processes, being placed outside the vertebral artery, and
beneath the intertransverse and other muscles fixed to those processes.
In front of the intertransverse muscles, the nerve divides into an
ascending part, which joins the first cervical nerve, and a descending
part to the third,

Fig. 354. — Diagrammatic
OUTLINE OF THE CeER-
VICAL AND BRACHTAL
Puexuses. (A. T.) 3
The nerves are separated

from the spinal cord at

their origin and are sup-
posed to be viewed from
before. Cl, is placed op-
posite the roots of the first
cervical or — sub-occipital
nerve, and the Roman num-

bers in succession from II,

to VIII, opposite the roots

of the corresponding cer-
vical nerves ; DI, is placed
opposite to the roots of the

first dorsal nerve, and II,

and III, opposite the second

and third nerves ; the origin
of the posterior primary
branch is shown in all the
nerves : of these p 2, indi-
cates the great occipital
from the second, and p 3,
the smallest occipital nerve
from the third. Cervical
plexus ; 1, anterior primary
branch of the first cervical
nerye and loop of union with
the second nerve; 2, lesser
occipital nerve proceeding in
this case from the second
cervical nerve, more fre-
quently from the second and
third; 3, great auricular
nerve from the second and
third ; 3’, superficial cervical
nerve from the third ; 3 n,
communicating branches to
the descendens noni from
the second and third; 3s, communicating to the spinal accessory from the second, third,
and fourth ; 4, supraclavicular and supra-acromial descending nerves: the loops or
arches of communication between the four upper cervical nerves, and between the fourth
and fifth, are shown ; 4’, the phrenic nerve springing from the fourth and fifth nerves.

Brachial plexus: V', to VII’, and D’, the five roots of the brachial plexus ; 5, the

rhomboid nerve ; 5’, suprascapular ; 5", posterior thoracic ; 6, nerve to the subclavius

muscle ; 7, 7, inner and outer anterior thoracic nerves ; 8, 8’, 8", upper and lower sub-
scapular nerves. In the larger nerves proceeding to the shoulder and arm from the
plexus, those of the anterior division are represented of a lighter shade, those belonging

to the posterior division darker ; ec, external cutaneous or musculo-cutaneous ; ™, median 2

u, ulnar, ic, internal cutaneous ; w, nerve of Wrisberg ; 7, musculo-spiral ; c, circum-

flex ; i, intercostal nerves ; 2’, lateral branch of the same ; if, intercosto-humeral nerves.

THE CERVICAL PLEXUS, 577

CERVICAL PLEXUS.

The cervical plexus is formed by the anterior divisions of the first
four cervical nerves, and distributes branches to some of the muscles of
the neck, and to a portion of the integument of the head and neck. It
is placed opposite the first four vertebrae, beneath the sterno-mastoid
muscle, and rests against the middle scalenus muscle and the levator
anguli scapule. The disposition of the nerves in the plexus is easily
recognised. Hach nerve, except the first, branches into an ascending
and a descending part: and these are united in communicating loops
with the contiguous nerves. From the union of the second and third
nerves, superficial branches are supplied to the head and neck ; and from
the junction of the third with the fourth, arise the cutaneous nerves of
the shoulder and chest. Muscular and communicating branches spring
from the same nerves.

The BRANCHES of the plexus may be separated into two sets—a
superficial and deep ; the superficial consisting of those which ramify
over the cervical fascia, supplying the integument and some also the
platysma ; the deep comprising branches which are distributed for the
most part to the muscles. The superficial nerves may be subdivided
into ascending and descending ; the deep nerves into an internal and
external series.

SUPERFICIAL ASCENDING BRANCHES.

Superficial cervical nerve.—This nerve takes origin from the
second and third cervical nerves, turns forward over the sterno-mastoid
muscle about the middle, and, after perforating the cervical fascia,
divides beneath the platysma myoides into two branches, which are dis-
tributed to the anterior and lateral parts of the neck.

a. The upper branch gives an ascending twig which accompanies the external
jugular vein, and communicates freely with the facial nerve (cervico-facial
division) ; it is then transmitted through the platysma to the surface, supplying
that muscle, and ramifies in the integument of the upper half of the front of
the neck, filaments reaching as high as the lower maxilla.

b. The lower branch likewise pierces the platysma, and is distributed below
the preceding, its filaments extending in front as low as the sternum.

The superficial cervical nerve may arise from the plexus in the form of two or
more distinct branches. Thus Valentin describes three superficial cervical
nerves, which he names superior, middle, and inferior. (‘‘ Sémmerring y. Bau,”
&e.)

While the superficial cervical nerve ramifies over the platysma myoides, the
facial nerve is beneath the muscle. According to Valentin many anastomotic
arches are formed on the side of the neck between those two nerves, as well as
between the branches of the former, one with another

Great auricular nerve.—This nerve winds round the outer border
of the sterno-mastoid, and is directed obliquely upwards beneath the
platysma myoides, between the muscle and the deep fascia of the neck,
to the lobe of the ear. Here the nerve gives a few small branches to
the face, and ends in the auricular and mastoid branches.

a. The auricular branches are directed to the back of the external ear, on
which they ramify, and are connected with twigs derived from the facial nerve.
One of these branches reaches the outer surface of the ear by a fissure between
the antihelix and the concha. A few filaments are supplied likewise to the outer
part of the lobule. .

You, I. PP

578 THE CERVICAL NERVES.

b. The mastoid branch is united to the posterior auricular branch of the facial
nerve, and ascends over the mastoid process to the integument behind the ear,

e. The facial branches of the great auricular nerve, which extend to the
integuments of the face, are distributed over the parotid gland. Some slender
filaments penetrate deeply through the substance of the gland, and communicate
with the facial nerve.

Small occipital nerve.—The smaller occipital nerve varies in size,
and is sometimes double. It springs from the second cervical nerve,
and is directed almost vertically to the head along the posterior border
of the sterno-mastoid muscle. Having perforated the deep fascia near
the cranium, the small occipital nerve is continued upwards between
the ear and the great occipital nerve, and ends in cutaneous filaments
which extend upwards in the scalp; it communicates with branches
from the larger occipital nerve, as well as with the posterior auricular
branch of the facial. It appears to supply sometimes the occipito-
frontalis muscle.

The auricular branch is distributed to the upper part of the ear on the posterior
aspect, and to the elevator muscle of the auricle. This auricular branch is an offset
from the great occipital nerve when the small occipital is of less size than usual.

TI. SUPERFICIAL DESCENDING BRANCHES.

Supraclavicular nerves.—The descending series of the superficial
nerves are thus named. There are two of these nerves, or, in some
cases, a greater number. They arise from the third and fourth cervical
nerves, and descend in the interval between the sterno-mastoid and the
trapezius muscles. As they approach the clavicle, the nerves are aug-
mented to three or more in number, and are recognised as internal,
middle, and posterior.

a. The internal (suprasternal) branch, which is much smaller than the rest,
ramifies over the inner half of the clavicle, and terminates near the sternum.

b. The middle branch (supraclavicular), lying opposite the interval between
the pectoral and deltoid muscles, distributes some twigs over the fore part of the
deltoid, and others over the pectoral muscle, The latter join the small cutaneous
branches of the intercostal nerves.

c. The eaternal or posterior branch (supra-acromial) is directed outwards over
the acromion, and the clavicular attachment of the trapezius muscle, and ends
in the integument of the outer and back part of the shoulder.

III. Deep BRANCHES: INNER SERIES.

Connecting branches.—The cervical plexus is connected near the
base of the skull with the trunks of the pneumo-gastric, hypoglossal,
and sympathetic nerves, by means of filaments intervening between
those nerves and the loop formed by the first two cervical nerves in
front of the atlas (p. 560).

Muscular branches.— Branches to the anterior recti muscles proceed
from the cervical nerves close to the vertebrae, including the loop
between the first two of these nerves.

Two branches to the ansa hypogiossi, one from the second, the other
from the third cervical nerve, descend over or under the internal
jugular vein, to form a loop of communication with the ramus de-
scendens noni, and aid in the supply of the muscles below the hyoid
bone (p. 567).

Phrenic nerve.—The diaphragmatic or phrenic nerve passes down
through the lower part of the neck and the thorax to its destination.

BRANCHES FROM THE CERVICAL PLEXUS. 57

9

It commences from the fourth cervical nerve, and receives usually a
fasciculus from the fifth. As it descends in the neck, the nerve is
jnclined inwards over the anterior scalenus muscle; and near the chest

Fig. 355.—View or THE Superricrat DisTRIBUTIOCN oF THE NERVES PROCEEDING FROM

THE CERVICAL PLEXvs (from Sappey after Hirschfeld and Leveillé). 3

1, superficial cervical nerve; 2, 2, descending branches of the same ; 3, ascending
branches ; 4, twigs uniting with the facial ; 5, great auricular nerve ; 6, its parotid
branch ; 7, its external auricular branch ; 8, twig of the same which pierces the auricle
to pass to its outer surface ; 9, branch to the deep surface of the pinna ; 10, its union
with the posterior auricular of the facial nerve ; 11, small occipital nerve ; 12, its branch
which unites with the great occipital nerve ; 13, a mastoid branch or second small
occipital ; 14, twigs from this to the back of the neck ; 15, 16, supraclavicular nerves ;
17, 18, supra-acromial nerves; 19, branch of the cervical nerves passing into the
trapezius muscle ; 20, spinal accessory distributed to the same and receiving a uniting
branch from the cervical nerves ; 21, branch to the levator scapule ; 22, trunk of the
facial nerve ; 23, its posterior auricular branch’ passing into the occipital and posterior
and superior auricular muscles ; 24, its cervico-facial branches.

$ PP2

580 THE CERVICAL NERVES.

it is joined by a filament of the sympathetic, and sometimes also by
another filament derived from the fifth and sixth cervical nerves.

As it enters the thorax each phrenic nerve is placed between the sub-
clavian artery and vein, and crosses over the internal mammary artery
near the root. It then takes nearly a straight direction, in front of the
root of the lung on each side, and along the side of the pericardium,—
between this and the mediastinal part of the pleura. Near the dia-
phragm it divides into branches, which separately penetrate the fibres
of that muscle, and then diverging from each other, are distributed on
the under surface.

The right nerve is placed more deeply than the left, and is at. first
directed along the outer side of the right innominate vein, and the
descending vena cava.

The nerve of the left side is a little longer than that of the right, in
consequence of the oblique position of the pericardium round which it
winds, and also because of the diaphragm being lower on this than on
the opposite side. This nerve crosses in front of the arch of the aorta
and the pulmonary artery before reaching the pericardium.

Besides the terminal branches supplied to the diaphragm, each phrenic nerve
gives filaments to the pleura and pericardium ; and receives sometimes an offset
from the union of the descendens noni with the cervical nerves. Swan notices
this union as occurring only on the left side. Luschka describes twigs from the
lower part of the nerve to the peritoneum, the inferior cava, and the right
auricle of the heart.

One or two filaments of the nerve of the right side join in a small ganglion
with branches to the diaphragm which are derived from the solar plexus of the
sympathetic ; and from the ganglion twigs are given to the suprarenal capsule,
the hepatic plexus, and the lower vena cava, On the left side there is a junction
between the phrenic and the sympathetic nerves near the cesophageal and aortic
openings in the diaphragm, but without the appearance of a ganglion.

IV. Deep BRANCHES: EXTERNAL SERIES,

Muscular branches.—The sterno-mastoid receives a branch from
the second cervical nerve. Two branches proceed from the third nerve
to the levator anguli scapule ; and from the third and fourth cervical
nerves, as they leave the spinal canal, branches are given to the middle
scalenus muscle. Further, the trapezius has branches prolonged to it ;
and thus, like the sterno-mastoid, this muscle receives nerves from both
the spinal accessory and the cervical plexus.

Connection with the spinal accessory nerve—In the substance of the sterno-
mastoid muscle, this nerve is connected with the branches of the cervical plexus
furnished to that muscle. It is also connected with the branches distributed to
the trapezius—the union between the nerves being beneath the muscle, and
having the appearance of a plexus; and with another branch of the cervical
plexus in the interval between the two muscles.

SUMMARY OF THE CERVICAL PLEXUS.—From the cervical plexus are
distributed cutaneous nerves to the back of the head, to part of the ear
and face, to the anterior half of the neck, and to the upper part of
the trunk. The muscles supplied with nerves from the plexus are the
sterno-mastoid, the platysma, and the lower hyoid muscles in parts
the anterior recti capitis, the levator anguli scapule, the trapezius,
the scalenus medius, and the diaphragm. By means of its branches

BRANCHES FROM THE CERVICAL PLEXUS. 581

the plexus communicates with the pneumo-gastric, spinal accessory,
hypoglossal, and sympathetic nerves.

Fig. 356.

jas)

Fig. 356.—Drrp Dissection oF THE AXILLA, SHOWING THE DBracutat PLEXUS AND

NEIGHBOURING Nerves (from Sappey after Hirschfeld and Leveillé), 4

The clavicle has been sawn through near its sternal end, and is turned aside with the
muscles attached to it ; the subclavius and the greater and lesser pectoral muscles have
been removed from the front of the axilla. 1, loop of union between the descendens noni
and a branch of the cervical plexus ; 2, pneumo-gastric ; 3, phrenic passing down to the
inner side of the scalenus anticus muscle ; 4, anterior primary division of the fifth cervical
nerye ; 5, the same of the sixth; 6, 7, the same of the seventh and eighth cervical
nerves ; 8, the same of the first dorsal nerve ; 9, 9, branch from the plexus to the sub-
clavyius muscle, communicating with the phrenic nerve ; 10, posterior thoracic nerve dis-
tributed to the serratus magnus ; 11. upper anterior thoracic nerve passing into the great
pectoral muscle ; 13, lower anterior thoracic distributed to the lesser pectoral ; 14, twig
of communication between these two nerves ; 12, suprascapular nerve passing through the
suprascapular notch ; 15, lower of the two subscapular nerves; 16, nerve of the teres
major; 17, long subscapular, or nerve of the latissimus dorsi; 18, accessory of
the internal cutaneous nerve ; 19, union of the accessory cutaneous with the second
and third intercostal nerves ; 20, lateral branch of the second intercostal ; 21, second
internal cutaneous or nerve of Wrisberg ; 22, internal cutaneous nerve ; 28, the ulnar
nerve to the inside of the axillary artery, passing behind the vein, and having, in
this case, a union with the upper division of the plexus ; 24, the median nerve im-
mediately below the place where its two roots embrace the artery, which is divided above
this place ; 25, the musculo-cutaneous nerve passing into the coraco-brachialis muscle ;
26, the musculo-spiral nerve passing behind the divided brachial artery.

582 THE BRACHIAL PLEXUS.

BRACHIAL PLEXUS.

This large plexus, from which the nerves of the upper limbs are
supplied, is formed by the union of the anterior trunks of the four
lower cervical and first dorsal nerves ; and it further receives a fas-
ciculus from the lowest of the nerves (fourth), which goes to form the
cervical plexus. The plexus extends from the lower part of the neck to
the axillary space, and terminates opposite the coracoid process of the
scapula in large nerves for the supply of the limb.

The manner in which the nerves are disposed in the plexus is liable
to some variation, but the following may be regarded as the arrange-
ment most frequently met with. The fifth and sixth cervical join
together at the outer border of the scalenus medius to form an upper
trunk ; similarly the eighth cervical and first dorsal unite together
between the scaleni muscles to form a lower trunk, while the seventh
cervical remains single, forming a middle trunk.

Soon after passing the outer border of the scaleni muscles each pri-
mary trunk divides so as to form an anterior and a posterior branch
The anterior branches of the upper and middle trunks unite together
to form what is called the upper or outer cord of the plexus; the ante-
rior branch of the lower trunk forms by itself the dower or inner cord of
the plexus, and the posterior branches of all three trunks unite together
to form the middle or posterior cord. The cords thus formed lie side by
side in the fore part of the plexus, and external to the first part of the
axillary vessels, but lower down they are placed, one on the outer side
of the axillary artery, one on the inner side, and one behind that vessel,
and are continued into the principal nerves for the arm.

Varieties.—Instead of three primary trunks, only two are found in a great
number of instances. This arises from the frequent union of the seventh nerve
with the trunk formed by the fifth and sixth nerves, which takes place at the
outer border of the scaleni muscles. The fasciculi which unite to form the
posterior cord are generally separated at a higher Jevel ihan the formation of the
two other cords, but they are also frequently given off as low as the clavicle, or
even farther dawn. As regards position, the fifth and sixth nerves or the fifth
alone not unfrequently pierce the upper fibres of the anterior scalenus muscie ;
the fifth nerve has even been found to pass altogether in front of that muscle.
(Turner, Nat. Hist. Review, 1864, and Journ. of Anat., 1872; Henle, Systematic
Anatomy, vol. iii.; Lucas, Guy’s Hosp. Reports, 1875, &c.)

BrancHEs.—The branches proceeding from the plexus are numerous,
and may be conveniently divided into two classes—viz., those that arise
above the clavicle, and those that take origin below the bone.

BRANCHES ABOVE THE CLAVICLE.

Above the clavicle there arise from the trunks of the orachial plexus,
the posterior thoracic and suprascapular nerves, a nerve for the rhom-
boid muscles, another for the subclavius, irregular branches for the
scaleni and longus colli, and a branch to join the phrenic nerve.

Small muscular branches.—The branches for the sealeni and longus colli
muscles spring in an irregular manner from the lower cervical nerves close to
their place of emergence from the vertebral foramina.

The branch for the rhomboid muscles arises from the fifth nerve, and is directed
vbackwards to the base of the scapula through the fibres of the middle calenus

NERVES OF THE SHOULDER. 583

and beneath the levator anguli scapule. It is distributed to the deep surface of
the rhomboid muscles, and gives sometimes a branch to the levator scapule.

The nerve of the subclavius masele, of small size, arises from the front of the
cord which results from the union of the fifth and sixth cervical nerves. It is
directed over the outer part of the subclavian artery to the deep surface of the
subclavius muscle. This small nerve is commonly connected with the phrenic
nerve in the neck or in the chest, by means of a slender filament.

Branch to join the phrenic nerve.—This small and short branch is an offset
from the fifth cervical nerve ; it joins the phrenic nerve on the anterior scalenus

muscle.

Fig. 857. — DIsTRIBUTION OF
THE SUPRASCAPULAR AND
CrrecumFLEX Nerves (from
Hirschfeld and Leviellé). 4

a, the scalenus medius and
posticus muscles ; 6, levator
anguli scapule ; c, acromion ;
d, deltoid muscle, of which
the back part has been de-
tached from the scapula and
in part removed ; e, rhomboid
muscle ; f, teres major; g, la-
tissimus dorsi ; 1, the brachial
plexus of nerves as seen from
behind ; 1’, the nerve of the
levator scapulie and rhomboid
muscles ; 2, placed on the
clavicle, marks the supra-
scapular nerve; 3, its branch
to the supraspinatus muscle ;
4, branch to the infraspinatus ;
5, placed on the back of the
humerus below the imsertion
of the teres minor, marks the circumilex nerve passing out of the quadrangular interval 5
6, its branch to the teres minor muscle: 7, branches to the deep surface of the deltoid ;
8, cutaneous branch to the back of the shoulder.

Posterior thoracic nerve.—The posterior thoracic nerve (nerve of the serra-
tus magnus; external respiratory of Bell) is formed in the substance of the middle
scalenus muscle by two roots, one from the fifth and another from the sixth
nerve, and reaches the surface of the scalenus lower than the nerve of the rhom-
boid musceles, with which it is often connected. It descends behind the brachial
plexus on the outer surface of the serratus magnus, nearly to the lower border of
that muscle, supplying 1t with numerous branches.

Suprascapular nerve.—The suprascapular nerve arises from the back of the
cord formed by the union of the fifth and sixth nerves, and bends beneath the
trapezius to the upper border of the scapula, where it passes between the muscles
and the bone. Entering the supraspinous fossa of the scapula, through the
suprascapular notch (beneath the ligament which crosses the notch), the supra-
scapular nerve supplies two branches to the supraspinatus, one near the upper,
the other near the lower part of the muscle, and it then descends through the
great scapular notch into the lower fossa, where it ends in the infraspinatus
muscle.

Articular branches.—In the upper fossa of the scapula, 2 slender articular
filament is given to the shoulder-joint, and in the lower fossa other twigs of the
nerve enter the same joint and the substance of the scapula.

Varieties.—The communicating branch to the phrenic nerve has been seen
to pass down into the thorax over the subclavian artery and even over the vein
before joining with the phrenic. The posterior thoracic nerve sometimes gets an
additional branch from the seventh cervical, and Lucas has recorded three

584 THE BRACHIAL PLEXUS.

instances in which it received a fourth branch or root from the eighth cervical.
Its highest root from the fifth cervical nerve is frequently united at its origin
with the nerve to the rhomboids,

BRANCHES BELOW THE CLAVICLE,

The several nerves now to be described are derived from the three
great cords of the plexus in the following order.

T'rom the upper or outer cord,—the external of the two anterior
thoracic nerves, the musculo-cutaneous, and the outer root of the
median

From the lower or inner cord,—the inner of the two anterior thoracic,
the nerve of Wrisberg, the internal cutaneous, the ulnar, and the inner
root of the median.

From the posterior cora,—the subscapular nerves, the circumflex, and
the musculo-spiral.

If the fasciculi of which the principal nerves are composed he followed
through the plexus, they may be traced to those of the spinal nerves which in
the subjoined table are named along with each trunk. The higher numbers
refer to the cervical nerves, the unit to the dorsal nerve :—

Subscapular from .« } Ulnar .. ‘ : fe 2) oy ay 2) |
Circumflex ‘ So aivich Internal cutaneous -ley
Musculo-spiral . : i Small internal cutaneous { ~"*
External cutaneous . EMD Oails 3 : outer 5.6.7,
Median . : : Mon sa fied estieriOn phorerle inner 8.1.

Anterior thoracic nerves.—The anterior thoracic nerves, two in
number, supply the pectoral muscles.

The external, or more superficial branch, arising from the outer cord,
crosses inwards over the axillary artery, and terminates in the great
pectoral muscle.

The znternal, or deeper branch, springing from the inner cord, comes
forwards between the axillary artery and vein to the small pectoral
muscle, and is joined by a branch from the external. This nerve pre-
sents a plexiform division beneath the small pectoral muscle, and sup-
plies branches to it and the larger pectoral muscle. The two nerves
are connected by a filament which forms a loop over the artery, at the
inner side.

Subscapular nerves.—These nerves, three in number, take origin
from the posterior cord of the plexus.

The wpper nerve, the smallest of the subscapmar nerves, penetrates
the upper part of the subscapular muscle. The mdddle nerve gives a
branch to the subscapularis at its axillary border, and ends in the teres
major muscle. There is sometimes a distinct nerve for the last-named
muscle.

The long subscapular nerve, the largest of the three, runs along the
lower border of the subscapular muscle to the latissimus dorsi, to which
it is distributed.

Circumflex nerve.—The circumflex nerve gives both muscular and
cutaneous nerves to the shoulder. Springing from the posterior cord,
this nerve is at first placed behind the axillary artery, but at the lower
border of the subscapular muscle it is inclined backwards with the
posterior circumflex artery, in the space between the scapula and teres
major muscle above the long head of the triceps, and separates into an

THE CIRCUMFLEX NERVE. 585

upper and a lower branch, which are distributed to the deltoid and
teres minor muscles, the integument of the shoulder, and the shoulder-
joint

Fig. 358.—DistripuTioN oF THE PosTERIOR CuTANEOUS
NERVES oF THE SHOULDER AND Arm (after Hirschfel

and Leveillé). +4

1, supra-acromial branches of the cervical nerves de-
scending on the deltoid muscle ; 2, ascending or reflected,
and 2’, descending cutaneous branches of the circumflex
nerve ; 3, inferior external cutaneous of the musculo-spiral
nerve ; 4, external and posterior cutaneous branches of the
musculo-cutaneous nerve to the forearm; 5, internal
cutaneous of the musculo-spiral; 6, intercosto-humeral
branches ; 7, twigs of the nerve of Wrisberg; 8, upper
posterior branch of the internal cutaneous nerve ; 9, lower
branch of the same.

a. The upper portion winds round the upper part of
the humerus, extending to the anterior border of the
deltoid muscle, to which it is distributed. One or two
cutaneous filaments, penetrating between the muscular
fibres, are bent downwards and supply the integument
over the lower part of the muscle.

b. The lower branch supplies offsets to the back part
of the deltoid, and furnishes the nerve to the teres
minor, which is remarkable in presenting a ganegli-
form enlargement. It then turns round the posterior
border of the deltoid below the middle, and ramifies
in the integument, over the lower two-thirds of that
muscle, one branch extending to the integument over
the long end of the triceps muscle.

c. Anarticular filament for the shoulder-joint arises
near the commencement of the nerve, and enters the
capsular ligament below the subscapular muscle

Varieties.—In two instances Turner has described
a branch of the circumflex nerve which supplies the
teres major. (Journ. of Anat. vol. vi., p. 104.)

Internal cutaneous nerve.—At its origin
from the inner cord of the brachial plexus,
this nerve is placed on the inner side of the axillary artery. It becomes
cutaneous about the middle of the arm, and after perforating the
fascia, or, in some cases, before doing so, is divided into two parts; one
paar for the anterior, the other for the posterior surface of the
orearm.

a. The anterior branch crosses at the bend of the elbow behind (in some cases
over) the median basilic vein, and distributes filaments in front of the forearm,
as far as the wrist; one of these is,in some instances, joined with a cutaneous
branch of the ulnar nerve.

b. The posterior branch inclines obliquely downwards at the inner side of the
basilic vein, and winding to the back of the forearm, over the prominence of the
internal condyle of the humerus, extends somewhat below the middle of the fore-
arm. Above the elbow this branch is connected with the smaller internal
cutaneous nerve (nerve of Wrisberg), and afterwards communicates with the
outer porticn of the internal cutaneous, and, according to Swan, with the dorsal
branch of the ulnar nerve. ’

c. A branch to the integument of the arm pierces the fascia near the axilla, and

586 NERVES OF THE UPPER LIMB.

reaches to the eibow, or nearly so, distributing filaments outwards over the
biceps muscle, . This branch is often connected with the intercosto-humeral
nerve.

Fig, 359.—ANTERIOR Curangous Nerves OF THE SHOULDER AND Arm (from Sappey
after Hirschfeld and Leveillé). 4

o

1, 1, supraclavicular and supra-acromial nerves from the cervical plexus; 2, 2, 2,
cutaneous branches of the circumflex nerve; 3, 4, upper branches of tbe internal cuta-
neous nerve ; 5, superior external cutaneous branch of the musculo-spiral ; 6, internal
cutaneous nerve piercing the deep fascia; 7, posterior branch ; 8, communicating twig
with one of the anterior branches ; 9, 10, anterior branches of this nerve, some turning
round the median basilic and ulnar veins ; 11, musculo-cutaneous nerve descending over
the median cephalic vein ; 12, inferior cutaneous branch of the musculo-spiral nerve.

Fig. 860.—AnTERIOR Cutaneous NERVES oF THE ForREARM AND Hanp (from Sappey
after Hirschfeld and Leveillé). 3
9, 10, 13, distribution of the anterior branches of the internal cutaneous nerve ; 14,
union of one of these with a twig of the ulnar nerve ; 12, inferior cutaneous branch of
the musculo-spiral nerve; 11, 15, distribution of the external cutaneous nerve; 16,
union of one of its branches with 17, the terminal branch of the radial nerve; 18,
palmar cutaneous branch of the median nerve; 19, 20, internal and external collateral
branches to the thumb from the median nerve; 21, external collateral to the index
finger ; 22, 23, collateral branches to the index, middle and fourth fingers ; 24, 25, col-
ateral branches from the ulnar nerve to the fourth and fifth fingers ; the network of
communicating twigs formed by the terminal branches of these cutaneous nerves is repre-
sented at the extremities of the fingers.

BRACHIAL CUTANEOUS NERVES. 587

Small internal cutaneous nerve.—The smaller internal cutaneous
nerve, or nerve of Wrisberg, destined for the supply of the integument
of the lower half of the upper arm on the inner and posterior aspect,
commonly arises from the inner cord of the brachial plexus in union
with the larger internal cutaneous and ulnar nerves. In the axilla it
lies close to the axillary vein, but it soon appears on the inner side of
that vessel, and communicates with the intercosto-humeral nerve. It
then descends along the inner side of the brachial vessels to about the
middle of the arm, where it pierces the fascia, and its filaments are
thence continued to the interval between the internal condyle of the
humerus and the olecranon.

Branches.—In the lower third of the arm, branches of this small nerve are
directed almost horizontally to the integument on the posterior aspect ; and the
nerve ends at the elbow by dividing into several filaments, some of which are
directed forwards over the inner condyle of the humerus, while others are pro-
longed downwards behind the olecranon.

Connection with the intercosto-humeral nerve,—This connection presents much
variety in different cases :—in some, there are two or more intercommunications,
forming a kind of plexus on the posterior boundary of the axillary space ; in
others, the intercosto-humeral nerve is of larger size than usual, and takes the
place of the nerve of Wrisberg, only receiving in the axilla a small filament from
the brachial plexus ; and this small communicating filament represents in such
cases the nerve of Wrisberg.

Musculo-cutaneous nerve.—The musculo-cutaneous or external
cutaneous nerve is deeply placed between the muscles as far as the
elbow, and below that point is immediately under the integument.
Arising from the brachial plexus opposite the small pectoral muscle, it
perforates the coraco-brachialis muscle, and, passing obliquely across
the arm between the biceps and brachialis anticus muscles, reaches the
outer side of the biceps a little above the elbow. Here it perforates the
fascia, and nearly opposite the elbow-joint it passes behind the median-
cephalic vein, and, inclining outwards, divides into two branches which
supply the integument on the outer side of the forearm, one on the
anterior, the other on the posterior aspect.

A. BRANCHES IN THE ARM :—

a. A branch to the coraco-brachialis and short head of the biceps is given off
before the nerve pierces the former muscle; and other filaments are furnished to
the coraco-brachialis, while the nerve lies among its fibres.

b. Branches to the biceps and brachialis anticus are given off while the nerve
is between those muscles.

c. Small filaments are given to the humerus and elbow-joint.

B. BRANCHES IN THE FOREARM :—

a. The anterior branch descends near the radial border of the forearm. It is
placed in front of the radial artery near the wrist, and distributes some filaments
over the ball of the thumb. Piercing the fascia, it accompanies the artery to the
back part of thecarpus. This part of the nerve is connected at the wrist with a
branch of the radial nerve.

b. The posterior branch is directed outwards to the back of the forearm, and
ramifies in the integument of the lower third, extending as far as the wrist, It
communicates with a branch of the radial nerve, and with the external cutaneous
branch of the musculo-spiral nerve,

Summary.—The musculo-cutaneous nerve supplies the coraco-
brachialis, biceps, and brachialis anticus muscles, and the integument

588 NERVES OF THE UPPER LIMB.

on the outer side of the forearm. Communications are established
between it and the radial and the external cutaneous branch of the
musculo-spiral.

Varieties.—In some cases it does not perforate the coraco-brachialis muscle.
It is frequently found to communicate by a cross branch with, or to be an offset
of the median nerve; and in the latter case, the coraco-brachialis muscle
receives a separate branch from the brachial plexus, which may be explained
thus,—that the main part of the musculo-cutaneous nerve, instead of piercing
the coraco-brachialis muscle, remains adherent to the outer root and trunk of the
median. "

Ulnar nerve.—The ulnar nerve, the largest branch of the inner
cord of the brachial plexus, descends on the inner side of the artery
of the limb as far as the middle of the arm, then turns backwards
through the internal intermuscular septum with the inferior profunda
artery, to reach the interval between the olecranon and the inner
condyle of the humerus. From the axilla to this place it is covered
only by the fascia, and it may be felt through the integument a little
above the elbow. It here passes between the two heads of the flexor
carpi ulnaris, ‘and it remains concealed by that muscle as far as the
middle of the forearm ; it thence extends in a straight course along the
outer margin of the muscle, between it and the ulnar artery, to the
outer side of the pisiform bone. Above the wrist it gives off a large
dorsal branch to the hand, and continuing onwards it enters the palm
on the surface of the annular ligament, and divides into muscular and
cutaneous branches.

The ulnar nerve usually gives off no branches in the upper arm.

A, BRANCHES IN THE FOREARM :—

a. Articular filaments are given to the elbow-joint as the nerve passes behind
it. Some filaments are also given to the wrist-joint.

b. Muscular branches.—One branch enters the upper part of the flexor carpi
ulnaris, and another supplies the two inner divisions of the deep flexor of the
fingers.

c. Cutaneous branches to the forcarm.—These two small nerves arise about the
middle of the forearm by a common trunk, One pierces the fascia, and turning
downward, joins a branch of the internal cutaneous nerve. This branch is often
absent. The second, a palmar branch, lies on the ulnar artery, which it accom-
panies to the hand. This little nerve gives filaments around the vessel, and
ramifies in the integument of the hand, joining in some cases with other cutaneous
offsets of the ulnar or median nerve.

d. Dorsal branch to the hand—This large offset, leaving the trunk of the ulnar
nerve two or three inches above the wrist, winds backwards beneath the flexor
carpi ulnaris and divides into branches; one of these ramifies on the inner side
of the little finger, another divides to supply the contiguous sides of that finger
and the ring finger, while a third joins on the back of the metacarpus with the
branch of the radial nerve which supplies the contiguous sides of the ring and
middle finger. The several posterior digital nerves, now described, are united
with twigs directed backwards from the anterior digital neryes of the same
fingers.

B. PALMAR BRANCHES :—

a. The deep branch separates from the trunk beyond the annular ligament, and,
dipping down through the muscles of the little finger in company with the deep
branch of the ulnar artery, it follows the course of the deep palmar arch across
the hand, It supplies the short muscles of the little finger as it pierces them ;
and as it lies across the metacarpal bone, it distributes two branches to each

BRANCHES OF THE ULNAR NERVE. 589

Fig. 361.—Drrr View oF ture Anterior NERVES oF THE SHOULDER AND Arm (from
Sappey after Hirschfeld and Leveillé), +

1, musculo-cutaneous nerve ; 2, its twig to the coraco-brachialis muscle ; 3, its branch
to the biceps ; 4, its branch to the brachialis anticus ; 5, twig of union with the median
nerve (a variety) ; 6, continuation of the nerve in its cutaneous distribution ; 7, musculo-
spiral nerve in the interval between the brachialis anticus and supinator longus; 8,
inferior external cutaneous branch of the musculo-spiral ; 9, the internal cutaneous and
small internal cutaneous nerves divided ; 10, anterior branch of the internal cutaneous ;
11, median nerve ; to the inside the ulnar nerve is crossed by the line from 11,

Fig. 362.—Drrp View or THe ANTERIOR NERVES OF THE ForEARM AND Hanp (from
Sappey after Hirschfeld and Leveillé). +

5

12, the median nerve ; 13, its branches to the pronator teres ; 14, branch to the super-
ficial flexor muscles, which have been removed ; 15, branch to the flexor digitorum pro-
fundus ; 16, branch to the flexor longus pollicis; 17, anterior interosseous branch ; 18,
cutaneous palmar branch cut short ; 19, branches to the short muscles of the thumb ;
20, 21, collateral branches to the thumb ; 22, 23, 24, collateral branches to the second,
third, and fourth fingers ; 25, branch given by the ulnar nerve to the flexor carpi ulnaris ;
26, branch to the flexor digitorum profundus ; 27, cutaneous communicating twig; 28,
dorsal branch of the ulnar ; 29, superficial palmar branch ; 30, 31, collateral branches
to the fourth and fifth fingers ; 32, deep palmar branch; 33, its branch to the short
muscles of the little finger ; 34, 35, 36, twigs given by the deep branch of the ulnar to
the third and fourth lumbricales, all the interossei, and the adductor pollicis.

590 NERVES OF THE UPPER LIMB.

interosseous space—one for the palmar, the other for the dorsal interosseous
muscle, and supplies filaments to the two innermost lumbricales muscles.
Opposite the space between the thumb and the index finger the nerve ends
in branches to the adductor pollicis, and the inner head of the flexor brevis
pollicis.

é. The remaining part of the nerve supplies a branch to the palmaris brevis
muscle and small twigs to the integument, and divides into two digital
branches.

Digital nerves—One of these belongs to the ulnar side of the little finger.
The other is connected in the palm of the hand with a digital branch of the
median nerve. and at the cleft between the little and ring fingers, divides into
the collateral nerves for these fingers. The terminal disposition of the
digital branches on the fingers is the same as that of the median nerve, to be
presently described.

Summary.—The ulnar nerve gives cutaneous filaments to the lower
part of the forearm (to a small extent), and to the hand on its palmar
and dorsal aspects. It supplies the following muscles, viz., the ulnar
flexor of the carpus, the deep flexor of the fingers (its inner half ), the
short muscles of the little finger with the palmaris brevis, the inter-
osseous muscles of the hand, the two internal lumbricales, the adductor
pollicis and the inner half of the flexor brevis pollicis. Lastly, it con-
tributes to the nervous supply of the clbow and wrist jomts.

Varieties.— When the occasional epitrochleo-anconeus muscle is present, it
receives a branch from the ulnar in the upper arm (Henle). From the same part
of the nerve also small branches have been found entering the inner head of the
triceps. In three instances, Gruber has found the nerve descending in front of
the inner condyle instead of behind. A case has been recorded in which the
ulnar nerve supplied also two branches to the flexor sublimis digitorum (Turner,
“Nat. Hist. Review,’ 1864). The usual anastomosis between the digital branches
of the median and ulnar nerves is sometimes wanting (Henle).

Median nerve.—The median nerve arises by two roots, one from
the outer, the other from the inner cord of the brachial plexus. Com-
mencing by the union of these roots in front or on the outer side of the
axillary artery, the nerve descends in contact with the brachial artery,
gradually passing inwards over it, and near the elbow is at the inner
side of the vessel. Crossing the bend of the arm it passes beneath the
pronator radii teres, separated by the deep slip of that muscle from the
ulnar artery, and continues straight down the front of the forearm,
between the flexor sublimis digitorum and flexor profundus. Arrived
near the wrist it lies beneath the fascia, between the tendons of the
flexor sublimis and that of the flexor carpi radialis. It then enters the
palm behind the annular ligament, and rests on the flexor tendons.
Somewhat enlarged, and of a slightly reddish colour, it here separates
into two parts of nearly equal size. One of these (the external) sup-
plies some of the short muscles of the thumb, and gives digital branches
to the thumb and the index finger; the second portion supplies the
middle finger, and in part the index and ring fingers.

The median nerve gives no branch to the upper arm.

A. BRANCHES IN THE FOREARM :—

In the forearm the median nerve supplies muscular branches, and,
near the wrist, a single cutaneous filament. All the muscles on the
front of the forearm (pronators and flexors), except the flexor carpi

BRANCHES OF THE MEDIAN NERVE. 591

ulnaris and part of the deep flexor of the fingers, are supplied from
this nerve.

a. The branches, for the superficial muscles are separate twigs given off from
the nerve below or near the elbow-joint, but the branch furnished to the pronator
teres often arises above the joint,

db. Anteriar intcrosseous nerve.—This is the longest branch of the median
nerve, and it supplies the deeper muscles of the forearm, Commencing at the
upper part of the forearm, beneath the superficial flexor of the fingers, it passes
downwards with the anterior interosseous artery on the interosseous membrane,
and between the long flexor of the thumb and the deep flexor of the fingers, to
the pronator quadratus muscle, in which it ends.

ec. The cvtaneous palmar branch pierces the fascia of the forearm close to the
annular ligament, and descending over that ligament, ends in the integument of
the palm about the middle: being connected by a twig with the cutaneous
“palmar branch of the ulnar nerve. It distributes some filaments over the ball
of the thumb, which communicate with twigs of the radial or the external cuta-
neous nerve.

B. BRANCHES IN THE HAND :—

a. Branch to muscles of the thimb,—This short nerve subdivides into branches
for the abductor, the opponens, and the outer head of the flexor brevis pollicis
muscle,

b. Digital nerves.—These are five in number, and belong to the thumb, and
the fingers as far as the outer side of the ring-finger. As they approach the
clefts between the fingers, they are close to the integument in the intervals
between the longitudinal divisions of the paimar fascia.

The jirst and second nerves lie along the sides of the thumb; and the former
(the outer one) is connected with the radial nerve upon the hall of the thumb.

The third destined for the radial side of the index finger, gives a muscular
branch to the first or most external lumbricalis muscle.

The fourth supplies the second lumbricalis, and divides into branches for the
adjacent sides of the index and middle fingers.

The fifth, the most internal of the digital nerves, is connected by a crossing-
twig with the ulnar nerve, and divides to furnish branches to the adjacent sides
of the ring and middle fingers,

Fig. 862*.—Duisrripution oF THE Drertan Nerves (from Hirschfeld and Fic, 369%
es ; ig. 362°,
Leveillé). 3
1, palmar collateral nerve ; 2, its final palmar distribution ; 3, its
dorsal or ungual distribution, and between these numbers the network of
terminal filaments ; 4, collateral dorsal nerve ; 5, uniting twigs passing
between the dorsal and palmar digital nerves.

Each digital nerve divides at the end of the finger into two
branches, one of which supplies the ball on the fore part of the
finger ; the other ramifies in the pulp beneath the nail. Branches
pass from each nerve forwards and backwards to the integument
of the finger ; and one larger than the rest inclines backwards by
the side of the first phalanx of the finger, and, after joining the
dorsal digital nerve, ends in the integument over the last phalanx.

Summary.—The median nerve gives cutaneous branches
to the palm, and to threeand a half fingers. It supplies
the pronator muscles, the flexors of the carpus and the
long flexors of the fingers (except the ulnar flexor of the carpus, and
part of the deep flexor of the fingers), likewise the outer set of the
short muscles of the thumb, and two, lumbricales.

592 NERVES OF THE UPPER LIMB.

Some similarity will be observed between the course and distribution
of the median and ulnar nerves. Neither gives any offset in the arm.
Together they supply all the muscles in front of the forearm and in the
hand, and together they supply the skin of the palmar surface of the
hand, and impart tactile sensibility to all the fingers.

Varieties. —One or both heads of the median may be double, and the outer
head may pass behind instead of in front of the brachial artery. (Turner.)
The whole nerve has frequently been seen passing behind the brachial artery.
(Turner, Gruber.) Gruber has also noticed one case in which the nerve entered
the forearm after passing completely over the pronator teres muscle.

Musculo-spiral nerve.—-The musculo-spiral nerve, the largest
offset from the brachial plexus, occupies chiefly the back part of the
limb, and supplies nerves to the extensor muscles, as well as to the
skin.

Arising behind the axillary vessels from the posterior cord of the
brachial plexus, of which it is the principal continuation and the only
one prolonged into the arm, it soon turns backwards into the musculo
spiral groove, and, accompanied by the superior profunda artery, pro-
ceeds along that groove, between the humerus and the triceps muscle,
to the outer side of the limb. It then pierces the external inter-
muscular septum, and descends in the interval between the supinator
longus and the brachialis anticus muscle to the level of the outer
condyle of the humerus, where it ends by dividing into the radial and
posterior interosseous nerves. Of these, the radial is altogether a cuta-
neous nerve, and the posterior interosseous is the muscular nerve of the
back of the forearm.

The branches of the musculo-spiral nerve may be classified according
as they arise on the inner side of the humerus, behind that bone, or on
the outer side.

A. INTERNAL BRANCHES :—

a. Muscular branches for the inner and middle heads of the triceps. That
for the inner portion of the muscle is long and slender; it lies by the side of
the ulnar nerve, and reaches as far as the lower third of the upper arm. One
branch, previously noticed by authors, but more particularly described by Krause,
is named by him the wlnar collateral branch. It arises opposite the outer border
of the latissimus dorsi tendon, and descends within the sheath of the ulnar*
nerve, through the internal intermuscular septum, and is distributed to the short
inferior fibres of the triceps (Reichert and Du Bois Reymond’s Archiv, 1864).

6. The internal cutaneous branch of the musculo-spiral nerve, commonly united
in origin with the preceding, winds backwards beneath the intercosto-humeral
nerve, and after supplying filaments to the skin, ends about two inches from the
olecranon ; in some instances extending as far as the olecranon. This nerve is
accompanied by a small cutaneous artery.

B. PostERIoR BRANCHES :—

These consist of a fasciculus of muscular branches which supply the outer head
of the triceps muscle and the anconeus. The branch of the anconeus is slender,
and remarkable for its length ; it descends in the substance of the triceps to
reach its destination.

C. EXTERNAL BRANCHES :—

a. The muscular branches supply the supinator longus, extensor carpi radialis
longior, (the extensor carpi radialis brevior receiving its nerve from the posterior
interosseous,) and frequently give a small branch to the brachialis anticus,

BRANCHES OF THE MUSCULO-SPIRAL NERVE. 593

(%) The eaternal cutaneous branches, two in number, arise where the nerve
pierces the external intermuscular septum.

The upper branch, the smaller of the two, is directed downwards to the fore
part of the elbow, along the cephalic vein, and distributes filaments to the lower
half of the upper arm on the anterior aspect. The lower branch extends as far
as the wrist, distributing offsets to the lower half of the arm, and to the fore-
arm, on their posterior aspect, and is connected near the wrist with a branch of
the external cutaneous nerve.

Fig. 363.

Fig. 363.—Dorsat Curangots NERVES

or THE Hanp. 4

The distribution delineated in this
figure is not the most common, there being
a larger than usual branch of the ulnar
nerve: 1, the radial nerve descending
beside the principal radial cutaneous vein ;
2 and 3, dorsal branches to the two sides
of the thumb; 4, branch to the radial
side of the forefinger ; 5, branch to the
forefinger and middle finger, communi-
cating with one from the ulnar nerve ;
6, the posterior branch of the ulnar nerve ;
7, communicating twig; 8, collateral
branch to the middle and ring fingers ;
9, collateral branch to the ring and little
fingers ; 10, branch to the inner side of
the hand and little finger.

Radial nerve.— The radial
nerve, continuing straight down
from the musculo-spiral, is con-
cealed by the long supinator mus-
cle, and lies a little to the outer
side of the radial artery. This
position beneath the supinator is
retained to about three inches
from the lower end of the radius,
where the nerve turns backwards
beneath the tendon of the muscle,
and becomes subcutaneous. It
then separates into two branches,
which ramify in the integument
on the dorsal aspect of the thumb and the next two fingers in the fol-
lowing manner.

(a) The external branch extends to the radial side of the thumb, and is joined
by an offset of the external cutaneous nerve. It distributes filaments over the
ball of the thumb,

(6) The internal portion communicates with a branch of the external cuta-
neous nerve on the back of the forearm, and divides into digital branches ; one
running along the ulnar side of the thumb, a second on the radial side of the
index finger, a third dividing to supply the adjacent sides of the index and
middle fingers, while a fourth joins with an offset from the dorsal branch of the
ulnar, and along with it forms a branch for the supply of the contiguous sides of
the middle and ring fingers. These branches communicate on the sides of the
fingers with the palmar digital nerves.

Sometimes the interspace between the middle and ring fingers is entirely sup-
plied by the radial, and at other times entirely by the ulnar nerve.

VOL. I. QQ

594 NERVES OF THE UPPER LIMB.

Posterior interosseous nerve.—This nerve, the larger of the two
divisions of the musculo-spiral nerve, winds to the back of the forearm
through the fibres of the supinator brevis muscle, and is prolonged
between the deep and superficial layers of the extensor muscles to the
jenereeeenus membrane, which it approaches about the middle of the
orearm.

Fig. 364. Fig. 364.—View or THE RapIAL SIDE OF THE ForEARM,
SHOWING THE FINAL DISTRIBUTION OF THE Muscuxo-
Sprrau Nerve (after Hirschfeld and Leveillé). 4

The supinator longus, and extensores carpi radiales longior
and brevior have been divided, and their upper parts re-~
moved ; the extensor communis digitorum is pulled back-
wards by a hook, and the supinator brevis has been par-
tially dissected to show the posterior interosseous nerve
passing through it.

1, placed upon the tendon of the biceps muscle, points
to the musculo-cutaneous nerve; 1’, near the wrist, the
lower part of this nerve and its plexus of union with the
radial nerve ; 2, trunk of the musculo-spiral nerve emerg-
ing from between the brachialis anticus, on which the
number is placed, and the supinator longus muscle ; 2’,
its muscular twigs to the long supinator and long radial
extensor of the carpus ; 2”, the posterior interosseous nerve
passing through the substance of the supinator brevis ; 3,
placed upon the cut lower portion of the supinator longus,
and Jower down the radial nerve ; 4, the external collateral
nerve of the thumb ; 5, the common collateral of the fore-
finger and thumb ; 6, the common collateral of the fore-finger
and middle finger ; 7, the twig of union with the dorsal
branch of the ulnar nerve ; 8, placed upon the common ex-
tensor of the fingers, the muscular branches of the posterior
interosseous nerve to the long extensor muscles ; 9, upon
the extensor secundi internodii pollicis, the branches to the
short extensor muscles.

Much diminished in size by the separation
of numerous branches for the muscles, the
nerve lies at the lower part of the forearm
beneath the extensor of the last phalanx of the
thumb and the tendons of the common extensor
of the fingers, and terminates on the back of
the carpus in a gangliform enlargement, from
which filaments are given to the adjoining
ligaments and articulations.

The branches of the interosseous nerve enter the surrounding muscles, viz., the
extensor carpi radialis brevior and supinator brevis, the superficial layer of the
extensor muscles, except the anconeus, and the deep layer of the same muscles :—
that is to say, the nerve supplies the supinators, and the extensors of the carpus
and fingers, with the exception of the supinator longus and the extensor carp!
radialis longior,

Summary.—The musculo-spiral nerve distributes its branches to the
extensor muscles of the elbow-joint exclusively, with the exception of a
filament to the brachialis anticus, which, however, receives its principal
nerves from another source. Before separating into its two large
divisions, the nerve gives branches to two muscles of the forearm, viz.,
the long supinator, and the long radial extensor of the carpus. The

UPPER DORSAL NERVES. 595

posterior interosseous division distributes nerves to the remaining
muscles on the outer and back part of the forearm, except the
anconeus (previously supplied), viz., to the short supinator and the
extensors.

Cutaneous nerves are distributed, from the trunk of the nerve and
its radial division, to the lower part of the upper arm, to the forearm,
and to the hand—on the posterior and outer aspect of each.

Varieties.—The dorsal branch of the radial nerve sometimes supplies the
whole of the back of the hand and fingers. In a single case recorded by Turner
the posterior interosseous did not form the so-called ganglion behind the carpus,
but passed down to supply the adjacent sides of the index and middle fingers.

DORSAL NERVES.

These nerves are twelve in number, and, with the exception of the
larger part of the first of them, which joins the brachial plexus, they
are distributed to the walls of the thorax and abdomen. Eleven of the
nerves so distributed are termed intercostal, and the twelfth is situated
below the last rib. The cords connecting them with the sympathetic
nerve, placed close to the vertebra, are very short.

The anterior divisions of these nerves pass separately to their destina-
tion, without forming any plexus by the connection or interlacement of
their fibres, and in this respect they differ from those of the other
spinal nerves. From the intervertebral foramina they are directed
transversely across the trunk, and nearly parallel one to another. The
upper six nerves, with the exception of the first, are confined to the
parietes of the thorax ; while the lower six nerves are continued from
the intercostal spaces to the muscles and integument of the anterior
wall of the abdomen.

FIRST DORSAL NERVE.

The greater nart of the anterior division of this nerve ascends over
the neck of the first rib and the first intercostal artery to enter into the
brachial plexus. The remaining portion of the nerve is continued as
the first intercostal, a small branch which courses along the first inter-
costal space, in the manner of the other intercostal nerves, but has
usually no lateral cutaneous branch, and may also want the anterior
cutaneous.

UPPER OR PECTORAL INTERCOSTAL NERVES.

In their course to the fore part of the chest, these nerves accompany
the intercostal blood-vessels. After a short space they pass between
the internal and external intercostal muscles, supplying them with
twigs, and, about midway between the vertebrae and the sternum, give
off the lateral cutaneous branches. The nerves, greatly diminished,
are now continued forwards amid the fibres of the internal intercostal
muscles as far as the costal cartilages, where they come into contact
with the pleura. In approaching the sternum, they cross the internal
mammary artery and the fibres- of the triangularis sterni muscle.
Finally, these nerves pierce the internal intercostal muscle and the

@Q2

596 THE DORSAL NERVES.

Fig. 365,

Fig. 365.—View oF THE ANTERIOR Divisions OF THE DoRSAL AND SOME OF THE
OTHER SpInAL NERVES From BEFORE (from Hirschfeld and Leveillé).

Lt
4

The pectoralis major and minor muscles have been removed ; on the right side the
rectus abdominis and internal oblique muscles are shown, on the left side the anterior
part of the rectus is cut away, and the transversalis is exposed.

1, the median and other nerves of the brachial plexus ; 2, the internal cutaneous ;

NERVES OF THE THORAX. 597

3, the nerve of Wrisherg ; 4, the intercostal nerves continued forwards to 4’, their ante-
rior cutaneous twigs ; 5, the lateral cutaneous branches of these nerves ; 6, cutaneous
branch of the last dorsal spinal nerve ; 7, the iliac twig of the ilio-hypogastric branch
of the first lumbar nerve ; 8, termination of the ilio-hypogastric ; 9, the ilio-inguinal ;
10, the middle cutaneous of the thigh.

ereater pectoral, and end in the integument of the breast, receiving the
name of the anterior cutaneous nerves of the thorax.

At the anterior part of the chest some of the muscular twigs cross the car-
tilages of the ribs, passing from one intercostal space to another.

(a) The lateral cutaneous nerves of the thorax pierce the external inter-
costal and serratus magnus muscles, in a line a little behind the pectoral border
of the axilla. The first intercostal usually gives no lateral pranch or only a
slender twig to the axilla, but, when that of the second nerve is unusually small,
it is supplemented by that of the first. The branch from the second intercostal
is named intercosto-humeral. and requires separate description. Each of the
remaining lateral cutaneous nerves divides into two branches, which reach the
integument at a short distance from each other, and are named anterior and
posterior.

The anterior branches are continued forwards over the border of the great
pectoral muscle. Several reach the mammary gland and the nipple; and from
the lower nerves twigs are supplied to the digitations of the external oblique
muscle of the abdomen.

The posterior branches turn backwards to the integument over the scapula and
the latissimus dorsi muscle. The branch from the third nerve ramifies in the
axilla, and a few filaments reach the arm.

The intercosto-humeral nerve, the lateral cutaneous branch of the second inter-
costal nerve, corresponds with the posterior of the two divisions of the succeeding
lateral [cutaneous branches, the anterior being commonly wanting. It crosses
the axillary space to reach the arm, and is connected in the axilla with an offset
of the nerve of Wrisberg. Penetrating the fascia it becomes subcutaneous, and
ramifies in the integument of the upper half of the arm, on the inner and pos-
terior aspect; a few filaments reach the integument over the scapula. The
branches of this nerve cross over the internal cutaneous offset of the musculo-
spiral, and a communication is established between the two nerves. The size of
the intercosto-humeral nerve, and the extent of its distribution, are in the
inverse proportion to the size of the other cutaneous nerves of the upper arm,
especially the nerve of Wrisberg.

(6) The anterior cutaneous nerves of the thorax, which are the terminal
twigs of the intercostal nerves, are reflected outwards in the integument over the
great pectoral muscle. The branch from the second nerve is connected with the
superclavicular and the lateral cutaneous nerves ; those from the third and fourth
nerves are distributed to the mammary gland.

LOWER OR ABDOMINAL INTERCOSTAL NERVES.

The lower intercostal nerves are continued from the anterior ends of
the intercostal spaces, between the internal oblique and the transverse
muscle of the abdomen, to the outer edge of the rectus. Perforating
the sheath, they enter the substance of that muscle, and afterwards
terminate in small cutaneous branches (anterior cutaneous).

(a) The lateral cutaneous nerves of the abdomen pass to the integument
through the external intercostal and external oblique muscles, in a line with the
corresponding nerves on the thorax, and divide in the same manner into anterior
and posterior branches.

The anterior branches are the larger, and are directed inwards in the super-
ficial fascia, with small cutaneous arteries, nearly to the edge of the rectus
muscle. =

598 THE DORSAL NERVES.

The posterior branches bend backwards over the latissimus dorsi muscle.

(4) The anterior cutaneous nerves of the abdomen become subcutaneous
near the linea alba, accompanying the small perforating arteries. Their number
and position are very uncertain. They are directed outwards towards the lateral
cutaneous nerves. A second set is described by Cruveilhier as existing at the
outer edge of the rectus muscle.

LAST DORSAL NERVE.

The anterior primary division of this nerve is below the last rib, and
is contained altogether in the abdominal wall. The nerve has the
general course and distribution of the others between the internal
oblique and transversalis, but, before taking its place between those
muscles, it passes in front of the upper part of the quadratus lumborum,
and pierces the posterior aponeurosis of the transverse muscle. This
nerve is connected by offsets with the nerve above, and occasionally
with the ilio-hypogastric branch of the lumbar plexus. Near the spine
it sometimes communicates with the first lumbar nerve by means of a
small cord in the substance of the quadratus lumborum.

The lateral cutaneous branch of the last dorsal nerve, passing
through both oblique muscles, is directed downwards over the iliac
crest to the integument, covering the fore part of the gluteal region
and the upper and outer part of the thigh, some filaments reaching as
far as the great trochanter of the femur.

LUMBAR NERVES.

The anterior divisions of the lumbar nerves increase in size from the
first to the fifth ; and all, except the fifth, which passes down to join
the sacral nerves, are connected together by communicating loops, so as
to form the lumbar plexus. On leaving the intervertebral foramina
these nerves are connected by filaments with the sympathetic nerve,
these filaments being longer than those connected with other spinal
nerves, in consequence of the position of the lumbar sympathetic
ganglia on the fore part of the bodies of the vertebre. In the same
situation are furnished small twigs to the psoas and quadratus lum-
borum muscles.

LUMBAR PLEXUS.

The lumbar plexus is formed by the communications between the
anterlor primary divisions of the four upper lumbar nerves. It is
placed in the substance of the psoas muscle, in front of the transverse
processes of the corresponding vertebree. Above, the plexus is narrow,
and is sometimes connected with the last dorsal nerve by a small offset
from that nerve, named dorsi-lumbar ; below it is wider, and is joined
to the sacral plexus by means of a branch given by the fourth lumbar
nerve to the fifth.

The arrangement of the plexus may be thus stated. The first nerve
gives off the ilio-hypogastric and ilio-inguinal nerves, and sends down-
wards a communicating branch to the second nerve. The second
furnishes the greater part of the genito-crural and external cutaneous
nerves, and gives a connecting branch to the third, from which some of
the fibres of the anterior crural and obturator nerves are derived.
From the third nerve, besides the descending branch to the fourth,

oe

THE LUMBAR PLEXUS. 599

two branches proceed; one of these, the larger, forms part of the
anterior crural nerve; the other, a part of the obturator nerve. The
fourth nerve gives two branches, which serve to complete the obturator

Fig. 366. — DracRAMMATIc Fig. 366.
OUTLINE OF THE LUMBAR
AND SACRAL PLEXUSES WITH
THE PRINCIPAL NERVES
ARISING FROM THEM. 4

D,XII, placed opposite the
divided roots of the last dorsal
nerve ; L,I to V, opposite the
roots of the five lumbar nerves :
the loops uniting the anterior
primary divisions of these
nerves together, and the first
with the twelfth dorsal are
shown; §,I to V, and C,I, the
same in the sacral and coccy-
geal nerves ; p, placed on some
of the nerves marks the pos-
terior primary divisions cut
short ; p, p’ the plexus formed
by the union of the posterior
branches of the third, fourth,
and fifth sacral and the coccy-
geal nerves ; d, the abdominal
continuation of the last dorsal
nerve, from which d’ the iliac
cutaneous branch arises; 1, 1’,
the ilio-hypogastric and ilio-
inguinal branches of the first
lumbar nerve ; 2, the genito-
crural rising by a loop from
the first and second lumbar ;
2’, external cutaneous of the
thigh rising by a loop from the
second and third ; ps, branches
to the psoas muscle along the
lumbar plexus'; cv, anterior
crural nerve from the second,
third, and fourth lumbar ; 2,
branches to the iliacus ; 0b,
obturator nerve from the se-
cond, third, and fourth lumbar
nerves ; 0b, accessory obtura-
tor; IV’, V’, loop from the
fourth and fifth lumbar, form-
ing the lumbo-sacral cord ; 3,
superior gluteal nerve ; sc,
sacral plexus ending in the great
sciatic nerve; 4, lesser sciatic
nerve rising from the plexus
posteriorly ; 4’, inferior gluteal
branches ; 5, inferior puden-
dal; 5’, posterior cutaneous
of the thigh and leg; 6, 6,
branches to the obturator in-
ternus and gemellus superior ; 6’, 6’, branches to the gemellus inferior, quadratus and
hip-joint ; 7, twigs to the pyriformis ; 8, 8, pudic nerve from the first, second, third, and
fourth sacral ; 9, visceral branches ; 9’, twig to the levator ani ; 10, cutaneous from the
ee which passes round the lowe, border of the gluteus maximus; 11, coccygeal

ranches, x

600 THE LUMBAR NERVES.

and anterior crural nerves, and a connecting branch to the fifth
nerve.

The BRANCHES of this plexus form two sets, which are distributed,
one to the lower part of the wall of the abdomen, the other to the fore
part and inner side of the lower limb. In the former set are the ilio-
hypogastric and ilio-inguinal nerves, and part of the genito-crural ; and
to the latter belong the remaining part of the genito-crural nerve, the
external cutaneous, the obturator, and the anterior crural nerves.

Tlio-hypogastric and ilio-inguinal nerves.

These nerves are the upper two branches from the lumbar plexus ;
they are both derived from the first lumbar nerve, and have a nearly
similar distribution. They become subcutaneous by passing between
the broad muscles of the abdomen, and through the outer one, and end
in the integument of the groin and scrotum in the male, and the labia
pudendi in the female, as well as in the integument covering the gluteal
muscles. The extent of distribution of the one is inversely proportional
to that of the other.

The ilio-hypogastric nerve, emerging from the upper part of the
psoas muscle at the outer border, runs obliquely over the quadratus
lumborum to the iliac crest, and there perforating the transverse muscle
of the abdomen, gets between that muscle and the internal oblique,
and divides into an iliac and hypogastric branch.

(a) The iliac branch pierces the attachment of both oblique muscles, immedi-
ately above the iliac crest, and is lost in the integument over the gluteal muscles,
behind the distribution of the lateral cutaneous branch of the last dorsal nerve.

(6) The hypogastric or abdominal branch passes on between the transverse and
internal oblique muscles, and is connected with the ilio-inguinal nerve near the
iliac crest. It then perforates the internal oblique muscle, and, piercing the
aponeurosis of the external oblique, a little above the superficial inguinal opening,
is distributed to the skin of the abdomen above the pubes.

The size of the iliac branch of this nerve varies inversely with that of the
lateral cutaneous branch of the twelfth dorsal. The hypogastric branch is not
unfrequently joined with the last dorsal nerve between the muscles, near the
crest of the innominate bone.

_ The ilio-inguinal nerve, smaller than the preceding, supplies the
integument of the groin. Descending obliquely outwards over the
quadratus lumborum, it crosses the fibres of the iliacus muscle, being
placed lower down than the ilio-hypogastric: it then perforates’ the
transverse muscle further forwards than the ilio-hypogastric ; com-
municating with that nerve between the abdominal muscles. Then
piercing the interng! oblique muscle, it descends in the inguinal canal,
and émerging at the superficial inguinal ring, is distributed to the skin
upon the groin, as well as to that upon the scrotu.a and penis in the
male, or the labium pudendi in the female, communicating with the
inferior pudendal nerve. In its progress this uerve furuishes branches
to the internal oblique muscle.

Varieties.—The ilio-inguinal nerve occasionally arises from une loop connect-
ing the first and second lumbar nerves. It is sometimes small, and ends near the
iliac crest by joining the ilio-hypogastric nerve ; in which case the latter gives

NERVES OF THE GROIN. 601

off an inguinal branch haying a similar course and distribution to the ilio-inguina.
nerve, the place of which it supplies.
Genito-crural nerve.

The genito-crural nerve belongs partly to the external genital
organs and partly to the thigh. It is derived chiefly from the

Vig. 367.

Fig. 367.—Visw FROM BEFORE OF THE ANTERIOR BRANCHES OF THE LUMBAR AND Sackab
Nerves witH tHE Purxusus (from Sappey, after Hirschfield and Leveillé). 4

1, lumbar cord of the great sympathetic nerve ; 2, 2’, anterior primary division of the
twelfth dorsal nerve ; 3, first lumbar; 4, 4’, ilio-inguinal branch of this nerve ; 5, 5’,
ilio-hypogastric branch ; 6, second lumbar nerve ; 7, 7’, genito-crural nerve rising from
the first and second lumbar; 8, 8’, external cutaneous nerve of the thigh; 9, third
lumbar nerve ; 10, fourth ; 11, fifth; 12, lumbo-sacral trunk; 13, iliac branch of the
ilio-inguinal ; 14, its abdominal branch ; 15, its genital branch ; 16, external cutaneous
nerve of the right side passing out of the pelvis under Poupart’s ligament ; 17, 17, 17,
cutaneous ramifications of this nerve ; 17, the same nerve exposed on the left side ; 18,
18’, genital branch of the genito-crural ; 19, its crural branch on the right side becoming
cutaneous ; 19’, the same on the left side exposed as it descends in front of the femoral
artery ; 20, anterior crural nerve ; 21, 21’, obturator nerve ; 22, left sciatic plexus; 25,
aortic plexus of the sympathetic nerve connected superiorly with the other pre-aortic
plexuses and the lumbar ganglia, and inferiorly with the superior plexus,

602 THE LUMBAR NERVES.

second lumbar nerve, but receives also a few fibres from the con-
necting cord between that and the first nerve. The nerve descends
obliquely through the psoas muscle, and afterwards on its fore
part, towards Poupart’s ligament, dividing at a variable height into
an internal or genital, and an external or crural branch. It often
bifurcates close to its origin from the plexus, in which case its two
branches perforate the psoas muscle in different places.

(a) The genital branch (external spermatic, Schmidt) lies upon or near the ex-
ternal iliac artery, and sends filaments along that vessel ; then perforating the
transversalis fascia, it passes through the inguinal canal with the spermatic cord,
and is lost upon the cremaster muscle. In the female it accompanies the round
ligament of the uterus.

(6) The crural branch (umbo-inguinal nerve, Schmidt) descends upon the
psoas muscle beneath Poupart’s ligament into the thigh. Immediately below
that ligament, and at the outer side of the femoral artery, it pierces the fascia
lata, and supplies the skin on the upper part of the thigh, communicating with
the middle cutaneous branch of the anterior crural nerve. Whilst it is passing
beneath Poupart’s ligament, some filaments are prolonged from this nerve on the
femoral artery. It is stated by Schmidt, that when the crural branch of the
genito-crural nerve is large, and commences near the plexus, he has observed it to
give a muscular branch to the lower border of the internal oblique and transver-
salis muscles.

External cutaneous nerve.

This nerve, commencing from the loop formed between the second
and third lumbar nerves, on emerging from the outer border of the
psoas muscle, crosses the iliacus muscle below the ilio-inguinal nerve,
and passing beneath Poupart’s ligament, reaches the thigh beneath the
anterior superior iliac spine, where it divides into an anterior and a
posterior branch distributed to the integument of the outer side of
the hip and thigh.

(a) The posterior branch perforates the fascia lata and subdivides into two or
three others, which turn backwards and supply the skin upon the outer surface
of the limb, from the upper border of the hip-bone nearly to the middle of the
thigh. The highest among them are crossed by the cutaneous branches from the
last dorsal nerve.

(6) An anterior branch, the continuation of the nerve, is at first contained in a
sheath or canal formed in the substance of the fascia lata ; but, about four inches
below Poupart’s ligament, it enters the subcutaneous fatty tissue, and is distri-
buted along the outer part of the front of the thigh, ending near the knee. The
principal offsets spring from its outer side. In some cases, this branch reaches
quite down to the knee, and communicates there with the internal saphenous
nerve.

Obturator nerve.

The obturator nerve is distributed to the adductor muscles of the
thigh, and to the hip and knee-joints. It arises from the lumbar
plexus by two roots, one from the third and the other from the fourth
lumbar nerve. Having emerged from the inner border of the psoas
muscle, opposite to the brim of the pelvis, it runs along the side of
the pelvic cavity, above the obturator vessels, as far as the opening
in the upper part of the thyroid foramen, through which it escapes
from the pelyis into the thigh. Here it immediately divides into an

THE OBTURATOR NERVE. 603

anterior and a posterior branch, which are separated from one another
by the short adductor muscle.

A.—The ANTERIOR PORTION communicates with the accessory ob-
turator nerve, when thet nerve is present, and descends in front of the
adductor brevis and behind the pectineus and adductor longus muscles.

It gives branches as follows.

(a) An articular branch to the hip-joint arises near the thyroid membrane.

(b) Muscular branches are given to the gracilis and adductor longus muscles,
and occasionally also others to the adductor brevis and pectineus.

(c) The terminal trig turns outwards upon the femoral artery, and surrounds
that vessel with small filaments.

(d) An offset at the lower border of the adductor longus communicates beneath
the fascia with the internal cutaneous branch of the anterior crural nerve, and
with a branch of the internal saphenous nerve, forming a sort of vlexus.

Fig. 368.—Tue Luawpar Piexus rrom
BEFORE, WITH THE DISTRIBUTION OF
SoME orf 11s Nerves (slightly altered

from Schmidt). 2

a, the last rib; 6, quadratus lum-
borum muscle ; ¢, oblique and trans-
verse muscles cut near the crest of the
ilium and turned down ; d, pubes ; e@,
adductor brevis muscle ; 7, pectineus
divided and turned outwards ; g, adduc-
tor longus ; 1, ilio-hypogastric nerve ;
2, ilio-inguinal ; 3, external cutaneous ;
4, anterior crural; 5, accessory obtu-
rator ; 6, obturator united with the ac-
cessory by a loop round the pubes ; 7,
genito-crural in two branches cut short
near their origin; 8, 8, lumbar portion
of the gangliated sympathetic cord.

B.—The PostTERIoR or DEEP
part of the obturator nerve,
having passed through some
fibres of the external obturator
muscle, crosses behind the short
adductor to the fore part of
the adductor magnus, where it
divides into many branches, all
of which enter those muscles,
excepting one which is pro-
longed downwards to the knee-
joint.

(a) The muscular branches supply
the external obturator and the great
adductor muscle, with the short adductor also when this muscle receives no
branch from the anterior division of the nerve.

(>) The articular branch for the knee rests at first on the adductor magnus,
but perforates the lower fibres of that muscle, and thus reaches the upper part of
the popliteal space. Supported by the popliteal artery, and sending filaments
around that vessel, the nerve then descends to the back of the knee-joint, and
enters the articulation through the posterior ligament. (Thomson, “ London
Med. and Surg. Journal,” No. xcy.) r

604 THE LUMBAR NERVES.

Varieties.— Occasional cutaneous nerve.—In some instances the communicat-
ing branch described is larger than usual, and descends along the posterior border
of the sartorius to the inner side of the knee, where it perforates the fascia, com-
municates with the internal saphenous nerve, and extends down the inner side of
the limb, supplying the skin as low as the middle of the leg.

When this cutaneous branch of the obturator nerve is present, the internal
cutaneous branch of the anterior crural nerve is small, the size of the two nerves
bearing an inverse proportion to each other.

Accessory obturator nerve.—The accessory obturator nerve, a small and incon-
stant nerve, arising from the obturator nerve near its upper end, or separately
from the same nerves of the plexus, descends along the inner border of the psoas
muscle, over the pubic bone, and, passing behind the pectineus muscle, ends by
dividing into several branches. Of these one joins the anterior branch of the
obturator nerve ; another penetrates the pectineus on the under surface ; whilst
a third enters the hip-joint with the articular artery.

This nerve is sometimes smaller than usual, and ends in filaments which perfo-
rate the capsule of the hip-joint. When it is altogether wanting, the hip-joint
receives branches from the obturator nerve.

Summary.—The obturator nerve and accessory obturator give
branches to the hip and knee joints, also to the adductor muscles of the
thigh, and, in some cases, to the pectineus. Occasionally a cutaneous
branch descends to the inner side of the thigh, and to the inner and
upper part of the leg.

Anterior crural nerve.

This nerve is the largest branch of the lumbar plexus, and is de-
rived principally from the third and fourth Jumbar nerves, but in
part also from the second. Emerging from the outer border of the
psoas muscle, near its lower part, it descends into the thigh in the
groove between that muscle and the iliacus, and, therefore, to the
outside of the femoral blood-vessels. It now becomes flattened out
and divides into two parts, one of which is cutaneous, while the other
is distributed to muscles.

BRANCHES OF THE TRUNK.—The branches given from the anterior
crural nerve within the abdomen are few and of small size.

(a) The tliacus receives three or four small branches, which are directed out-
wards from the nerve to the fore part of the muscle.

(b) The nerve of the femoral artery is asmall branch which divides into numerous
filaments upon the upper part of that vessel. It sometimes arises lower down
than usual in the thigh. It may, on the other hand, be found to take origin
above the ordinary position ; and in this case it proceeds from the middle cutaneous
nerve, when that branch springs from or near the lumbar plexus. In either case
its ultimate distribution is the same as that already described.

TERMINAL BRANCHES.—From the principal or terminal divisions of
the nerve the remaining branches take their rise as follows.

From the superficial division cutaneous branches are given to the fore
part of the thigh, and to the inner side of the leg. They are the middle
and internal cutaneous nerves, and the internal saphenous nerve. One
of the muscles, the sartorius, receives its nerves from this group.

The deep branches supply the muscles on the fore part of the thigh,
and also the pectineus muscle. The branch to the pectineus, however,
sometimes arises from the superficial part of the trunk.

A. Muscular branches.—The branch to the pectincus muscle crosses inwards
behind the femoral vessels, and enters the muscle on the anterior aspect.

THE ANTERIOR CRURAL NERVE. 605

The sartorius muscle receives three or four twigs, which arise in common with
the cutaneous nerves, and reach mostly the upper part of the muscle.

The rectus muscle receives a distinct branch on its under surface.

The nerve for the vastus externus, of considerable size, descends with the
branches of the external circumflex artery towards the lower part of the muscle.
It gives off a long slender articular filament, which reaches the knee and pene-
trates the fibrous capsule of the joint.

Fig. 369.—Derp Nerves oF THE ANTERIOR AND
INNER PART OF THE THIGH (from Sappey after
Hirschfeld and Leveillé) 2

1, anterior crural nerve ; 2, branches given to
the iliacus muscle ; 3, branch to the lower part of
the psoas; 4, large musculo-cutaneous branches,
divided to show the deeper nerves ; 5 and 6, mus-
cular filaments from the small musculo-cutaneous ;
7, origin of the cutaneous branches ; 8, communi-
cating filament of the internal cutaneous nerves ;
9, branches to the rectus ; 10, branches to the
vastus externus ; 11, branches to the vastus inter-
nus ; 12, internal saphenous nerve ; 13, its patellar
branch ; 14, its continuation down the leg; 15,
obturator nerve ; 16, branch from the obturator
nerve to the adductor longus; 17, branch to the
adductor brevis ; 18, branch to the gracilis ; from
this a filament is prolonged downwards, to unite
with the plexus formed by the union of branches
from the internal cutaneous and internal saphenous
nerves ; 19, deep branch of the obturator nerve to
the adductor magnus ; 20, lumbo-sacral trunk; 21,
its union with the first sacral nerve; 22, 22, lum-
bar and sacral part of the sympathetic nerve ; 23,
exterpal cutaneous nerve from the lumbar plexus.

Another large nerve divides into two sets of
branches, which enter the vastus internus and
the crureus about the middle of those muscles,
The nerve of the vastus internus, before pene-
trating the muscular fasciculi, gives a small
branch to the knee-joint. This articular nerve
passes along the internal intermuscular sep-
tum with a branch of the anastomotic artery,
as far as the inner side of the joint, where
it perforates the capsular ligament, and is
directed outwards on the synovial membrane
beneath the ligamentum patelle.

B. Middle cutaneous nerve.—The middle
cutaneous nerve either pierces the fascia lata
divided into two branches about four inches
below Poupart’s ligament, or as one trunk
which soon separates into two branches. These branches descend side by side
on the fore part of the thigh to the inner side and front of the patella. After
or before the nerve has become subcutaneous, it communicates with the crural
branch of the genito-crural nerve, and also with the internal cutaneous.

This nerve sometimes arises from the anterior crural, high up within the
abdomen.

C. Internal cutaneous nerve.—The internal cutaneous nerve gives branches
to the skin on the inner side of the thigh, and the upper part of the leg; but the
extent to which it reaches varies with the presence or absence of the “ occasional
cutaneous ” branch of the obturator nerve,

Lying beneath the fascia lata, this nerve descends obliquely over the upper

606 THE LUMBAR NERVES.

part of the femoral artery. It divides either in front of that vessel, or at the
inner side, into two branches (one anterior, the other internal), which pierce
the fascia separately. Before dividing, this nerve gives off two or three cutaneous
twigs, which accompany the upper part of the long saphenous vein. The highest
of these perforates the fascia near the saphenous opening, and reaches down to
the middle of the thigh. The others appear beneath the skin lower down by the
side of the vein ; one, larger than the rest, passes through the fascia about the
middle of the thigh, and extends to the knee. In some instances, these small
branches spring directly from the anterior crural nerve, and they often communi-
cate with each other.

Fig. 370. Fig. 870.—Curtanrous Nerves or THE ANTERIOR
AND InneR Part or THE THIcH (from Sappey
after Hirschfeld and Leveillé). 4

1, external cutaneous nerve; 2, 2, middle cuta-
neous branch of the anterior crural passing through
the sartorius muscle and the fascia; 3, 3, anterior
division of the internal cutaneous ; 4, filament to
the sartorius ; 5, inner or posterior division of the
internal cutaneous ; 6, its superficial branch to the
inside of the knee after perforating the fascia ; 7,
deep or communicating branch; 8, superficial
branch of the musculo-cutaneous of the crural; 9,
patellar branch of the internal saphenous nerve ;
10, continuation of the saphenous down the leg.

The anterior terminal branch, descending
in a straight line to the knee, perforates the
fascia lata in the lower part of the thigh ; it
afterwards runs down near the intermuscular
septum, giving off filaments on each side to the
skin, and is finally directed over the patella to
the outer side of the knee. It communicates
above the joint with a branch of the long
saphenous nerve; and sometimes it takes the
place of the branch usually given by the latter
to the integument over the patella.

This branch of the internal cutaneous nerve
sometimes lies above the fascia in its whole
length. It occasionally gives off a cutaneous
filament, which accompanies the long saphenous
vein, and in some cases it communicates with
the branch to be next described.

The inner branch of the internal cutaneous
nerve, descending along the posterior border of
the sartorius muscle, perforates the fascia lata
at the inner side of the knee, and communi-
cates by a small branch with the internal
saphenous nerve, which here descends in front
of it. It gives some cutaneous filaments to
the lower part of the thigh on the inner side,
and is distributed to the skin upon the inner
side of the lee. Whilst beneath the fascia, this branch of the internal cutaneous
nerve joins in an interlacement with offsets of the obturator nerve below the
middle of the thigh, and with the branch of the saphenous nerve nearer the
knee.

D. Internal saphenous nerve.—The internal or long saphenous nerve is the
largest of the cutaneous branches of the anterior crural nerve. In some cases it
arises in connection with one of the deep or muscular branches.

This nerve is deeply placed as far as the knee, and is subcutaneous in the rest

THE ANTERIOR CRURAL NERVE. 607

of its course. In the thigh it accompanies the femoral vessels, lying at first
somewhat to their outer side, but lower down approaching close to them, and
passing beneath the same aponeurosis. When the vessels pass through the open-
ing in the adductor muscle into the popliteal space, the saphenous nerve separates
from them, and is continued downwards beneath the sartorius muscle to the
inner side of the knee; where, having first given off, as it lies near the inner
condyle of the femur, a branch which is distributed over the front of the patella,
it becomes subcutaneous by piercing the fascia between the tendons of the sar-
torius and gracilis muscles.

The nerve then accompanies the saphenous vein along the inner side of the
leg, and passing in front of the ankle is distributed to the inner side of the foot.
In the leg it is connected with the internal cutaneous netve.

The distribution of the branches is as follows,

A communicating branch is given off about the middle of the thigh to join in
the interlacement formed beneath the fascia lata by this nerve and branches of
the obturator and internal cutaneous nerves. After it has left the aponeurotic
covering of the femoral vessels, the internal saphenous nerve has, in some cases,
a further connection with one or other of the nerves just referred to.

The branch to the integument in front of the patella perforates the sartorius
muscle and the fascia lata; and, haying received a communicating offset from
the internal cutaneous nerve, spreads out upon the fore part of the knee ; and, by
uniting with branches of the middle and external cutaneous nerves, forms a
plexus—plexus patelle.

A branch to the inner ankle is given off in the lower third of the leg, and
descends along the margin of the tibia, and some small filaments pierce the tarsal
ligaments.

SumMMARY.—The anterior crural nerve is distributed to the skin
upon the fore part and inner side of the thigh, commencing below the
termination of the ilio-inguinal and genito-crural nerves. It furnishes
also a cutaneous nerve to the inner side of the leg and foot. All the
muscles on the front and outer side of the thigh receive their nerves
from the anterior crural, and the pectineus is also in part supplied by
this nerve, and in part by the obturator. The tensor muscle of the
fascia lata is supplied from a different source, viz., the superior gluteal
nerve. Lastly, two branches are given from the anterior crural nerve
to the knee-joint

FIFTH LUMBAR NERVE.

The anterior branch of the fifth lumbar nerve, having received a
fasciculus from the nerve next above it, descends to join the first
sacral nerve, and forms part of the sacral plexus. The cord resulting
from the union of the fifth with a part of the fourth nerve, is named
the dwmbo-sacral nerve.

Superior Gluteal Nerve.—Before joining the first sacral nerve the
lumbo-sacral cord gives off from behind the superior gluteal nerve ;
this offset leaves the pelvis through the large sacro-sciatic foramen,
above the pyriformis muscle, and divides like the gluteal artery into
two branches, which are distributed chiefly to the smaller gluteal
muscles and tensor of the fascia lata.

(a) The upper branch runs with the gluteal artery along the origin of the
gluteus minimus, and is lost in it and in the gluteus medius.

(6) The lower branch crosses over the middle of the gluteus minimus between
this and the gluteus medius, and supplying filaments to both those muscles, is
continued forwards, and terminates inthe tensor muscle of the fascia lata,

608 THE SACRAL AND COCCYGEAL NERVES.

SACRAL AND COCCYGEAL NERVES.

The anterior divisions of the first four sacral nerves emerge from the
spinal canal by the anterior sacral foramina, and the fifth passes out
between the sacrum and coccyx.

The first two sacral nerves are large, and of nearly equal size; the
others diminish rapidly, and the fifth is exceedingly slender. Like the
anterior divisions of the other spinal nerves, those of the sacral nerves
communicate with the sympathetic ; the communicating cords are very
short, as the sympathetic ganglia are close to the inner margin of the
foramina of the sacrum.

The first three nerves and part of the fourth contribate to form the
sacral plexus. The fifth has no share in the plexus,—it ends on the
back of the coccyx. As the description of the fourth and fifth sacral
nerves and of the coccygeal will occupy only a short space, these three
nerves may be noticed first, before the other nerves and the numerous
branches to which they give rise are described.

WHE FOURTH SACRAL NERVE.

Only one part of the anterior division of this nerve joins the sacral
plexus ; the remainder, which is nearly half the nerve, supplies branches
to the viscera and muscles of the pelvis, and sends downwards a con-
necting filament to the fifth nerve.

(a) The visceral branches of the fourth sacral nerve are directed forwards to
the lower part of the bladder, and communicate freely with branches from the
sympathetic nerve. Offsets are distributed to the neighbouring viscera, accord-
ing #0 the sex. They will be described with the pelvic portion of the sympathetic
nerve. The foregoing branches are, in some instances, furnished by the third
sacral nerve instead of the fourth, and not unfrequently from both of these
nerves.

(b) Of the muscular branches, one supplies the Zevator ani, piercing that muscle
on the pelvic surface; another enters the coccygeus, whilst a third ends in
the external sphincter muscle of the rectum. The last branch, after passing
either through the coccygeus, or between it and the levator ani, reaches the
perineum, and is distributed likewise to the integuments between the anus and
the coccyx.

THE FIFTH SACRAL NERVE.

The anterior branch of this, the lowest sacral nerve, comes forwards
through the coccygeus muscle opposite the junction of the sacrum with
the first coccygeal vertebra ; it then descends upon the coccygeus nearly
to the tip of the coccyx, where it turns backwards through the fibres
of that muscle, and ends in the integament upon the posterior and
lateral aspect of the bone.

As soon as this nerve appears in front of the bone (in the pelvis) it is joined
by the descending filament from the fourth nerve, and lower down by the small
anterior division of the coccygeal nerve. It supplies small filaments to the
eoccygeus muscle.

THE COCCYGEAL NERY2&.

The anterior branch of the coccygeal, or, as it is sometimes named,
the sixth sacral nerve, is a very small filament. It escapes from the

THE SACRAL PLEXUS, 609

spinal canal by the terminal opening, pierces the sacro-sciatic ligament
and the coccygeus muscle, and, being joined upon the side of the coccyx
with the fifth sacral nerve, partakes in the distribution of that nerve.

THE SACRAL PLEXUS.
The lumbo-sacral cord (resulting as before described from the junction

Fig. 371. — DracramMatic Fig. 871.
OuTiIneE OF THE LuMBAR :
AND SACRAL PLEXUSES WITH
THE PRINCIPAL NERVES
ARISING FROM THEM. (A.T.)

The references to the nerves
of the lumbar plexus will be
found) ath pa 599s LV. Vi;
loop from the anterior primary
branches of the fourth and fifth
lumbar nerves, forming the
lumbo-sacral cord ; 3, superior
gluteal nerve ; SC, sacral
plexus ending in the great
sciatic nerve ; 4, lesser sciatic
nerve, rising from the plexus
posteriorly ; 4’, inferior gluteal
branches ; 5, inferior puden-
dal; 5’, posterior cutaneous
of the thigh and leg; 6, 6,
branches to the obturator in-
ternus and gemellus superior 3
6’, 6’, branches to the ge-
mellus inferior, quadratus and
hip-joint ; 7, twigs to the
pyriformis ; 8, 8, pudic from
the first, second, third, and
fourth sacral ; 9, visceral
branches ; 9’, twig to the
levator ani ; 10, cutaneous
from the fourth, which passes
round the lower border of the
gluteus maximus; 11, coccy-
geal branches.

of thefifth and part of the
fourth lumbar nerves), the
anterior divisions of the
first three sacral nerves,
and part of the fourth,
unite to form this plexus.
Its construction differs
from that of the other
spinal nervous plexuses in
this respect, that the
several constituent nerves
entering into it unite into
one broad flat cord. To
the place of union the
nerves proceed in different

directions, that of the upper ones- being obliquely downwards, while
VOL. I. RR

610 THE SACRAL NERVES.

that of the lower is nearly horizontal ; and, as a consequence of this
difference, they diminish in length from the first to the last. The
sacral plexus rests on the anterior surface of the pyriform muscle,
opposite the side of the sacrum, and escaping through the great sacro-
sciatic foramen, ends in the great sciatic nerve.

BRANCHES.—The sacral plexus gives rise to the great sciatic nerve,
and to various smaller branches ; viz., the pudic nerve, the small sciatic
nerve, and branches to the obturator internus, pyriformis, gemelli, and
quadratus femoris muscles.

Small Muscular branches.

a, To the pyriformis muscle, one or more branches are given, either from the
plexus or from the upper sacral nerves before they reach the plexus.

b. The nerve of the internal obturator muscle arises from the part of the plexus
formed by the union of the lumbo-sacral and the first sacral nerves. It turns
over the ischial spine of the hip-bone with the pudic vessels, and is then directed
forwards through the small sacro-sciatic foramen to reach the inner surface of
the obturator muscle.

c. To the levator ani one or more twigs proceed from the lower part of the plexus.

d. The superior gemellus receives a small branch, which arises from the lower
part of the plexus.

e. The small nerve which supplies the lower gemellus and quadratus femoris
muscles springs from the lower part of the plexus. Concealed at first by the
great sciatic nerve, it passes beneath the gemelli and the tendon of the internal
obturator,—between those muscles and the capsule of the hip-joint,—and reaches
the deep (anterior) surface of the quadratus. It furnishes a small articular fila-
ment to the back part of the hip-joint.

The Pudic Nerve.

This nerve, arising from the lower part of the sacral plexus, turns
over the spine of the ischium, and then passes forwards through the
small sacro-sciatic foramen, where it usually gives off the inferior
hemorrhoidal branch. It is next directed along the outer part of the
ischio-rectal fossa, in a sheath of the obturator fascia, along with the
pudic vessels, and divides into two terminal branches, the perineal
nerve and the dorsal nerve of the penis.

A.—The perineal nerve, the lower and much the larger of the two
divisions of the pudic nerve, lies below the pudic artery, and is expended
in superficial and muscular branches.

a. The superficial perineal branches are two in number, anterior and pos-
terior. The posterior branch, which first separates from the perineal nerve,
reaching the back part of the ischio-rectal fossa, gives filaments inwards to the skin
in front of the anus, and turns forwards in company with the anterior branch
to reach the scrotum. The anterior branch descends to the fore part of the
ischio-rectal fossa; and, passing forwards with the superficial perineal artery,
ramifies in the skin on the fore part of the scrotum andon the penis. This branch
sends small twigs to the levator ani muscle. The superficial perineal nerves are
accompanied to the scrotum by the inferior pudendal branch of the small sciatic
nerve. The three branches are sometimes named long scrotal nerves.

In the female, both the superficial perineal branches terminate in the external
labium pudendi.

b. The muscular branches generally arise by a single trunk, which is directed
inwards under cover of the transversalis perinzi muscle, and divides into offsets
which are distributed to the transversalis perinei, erector penis, accelerator
urine, and compressor urethre.,

THE PUDIC NERVE. 611

c. Slender filaments are sent inwards to the corpus spongiosum urethre ; some
of these, before penetrating the erectile tissue, run a considerable distance over
its surface.

Fig. 372.—Ricut Sipe oF THE
InTERIOR OF THE MAtzE PELvIS,
WITH THE Principat NERVES
DISPLAYED (after Hirschfeld and
Leveillé), 4

The left wall has heen removed
as far as the sacrum behind and
the symphysis pubis in front ; the
viscera and the lower part of the
levator ani have been removed ;
a, the lower part of the aorta ; a
placed on the fifth lumbar ver-
tebra, between the two common
iliac arteries, of which the left is
cut short ; J, the right external
iliac artery and vein ; c, the sym-
physis pubis ; d, the divided py-
riformis muscle, close to the left
auricular surface of the sacrum ;
e, bulb of the urethra covered by
the accelerator urine muscle ; the
membranous part of the urethra
cut short is seen passing into it ;
1, placed on the crest of the ilium,
points to the external cutaneous
nerye of the thigh passing over
the iliacus muscle ; 2, placed on
the psoas muscle, points to the
genito-crural nerve ; 3, obturator nerve ; 4, 4, placed on the lumbo-sacral cords ; that of
the right side points to the gluteal artery cut short ; 4’, the superior gluteal nerve ; 5,
placed on the inside of the right sacral plexus, points by four lines to the anterior divisions
of the four upper sacral nerves, which, with the lumbo-sacral cord, unite in the plexus ;
5’, placed on the fifth piece of the sacrum, points to the fifth sacral nerve; 5”, the
visceral branches proceeding from the third and fourth sacral nerves; 6, placed on the
lower part of the coccyx, below the coccygeal nerves ; 7, placed on he line of division of
the pelvic fascia, points to the nerve of ‘the levator ani muscle ; 8, placed at the lower
border of the great sacro-sciatic ligament, points to the cutaneous nerves of the anus ; 9,
nerve of the obturator internus ; 10”, the pudic nerve; 10’, is placed above the muscular
branches of the perineal nerve ; 10," the anterior and posterior superficial perineal nerves,
and on the scrotum the distribution of these nerves and the inferior pudendal nerve ; 11,
the right dorsal nerve of the penis; 11’, the nerve on the left crus penis which is cut
short ; 12, the continuation of the lesser sciatic nerve on the back of the thigh ; 12’, the
inferior pudendal branch ; 13, placed on the transverse process of the fifth lumbar ver-
tebra, marks the lowest lumbar sympathetic ganglion ; 14, placed on the body of the first
piece of the sacrum, points to the upper sacral sympathetic ganglia ; between 14 and 6,
are seen the remaining ganglia and sympathetic nervous cords, as well as their union with
the sacral and coccygeal nerves, and at 6, the lowest ganglion or ganglion impar.

B.—The dorsal nerve of the penis, the upper division of the pudic
nerve, accompanies the pudic artery in its course between the layers of
the deep perineal or subpubic fascia, and afterwards through the suspen-
sory ligament, to reach the dorsum. of the penis, along which it passes
as far as the glands, where it divides into filaments for the supply of that
part. On the penis, this nerve is joined by branches of the sympathetic
system, and it sends outwards numerous offsets to the integument on
the upper surface and sides of the organ, including the prepuce. One
large branch penetrates the corpus cavernosum penis.

RR 2

612 THE SACRAL NERVES.

In the female the dorsal nerve of the clitoris is much smaller than the
corresponding branch in the male ; it is similarly distributed.

C.—The inferior hemorrhoidal nerve arises from the pudic nerve at
the back of the pelvis, or it may come directly from the sacral plexus,
and be transmitted through the small sacro-sciatic foramen to its dis-

tribution in the lower end of the rectum.

Fig. 373.

Fig. 373.—DissEction oF THE PERINEUM or THE MALE To sHow THE DISTRIBUTION OF
rue Pupic AND OTHER Nerves (after Hirschfeld and Leveillé). 4

On the right side a part of the gluteus maximus muscle and the great sacro-sciatic liga-
ment have been removed to show the descent of the nerves from the great sacro-sciatic
foramen. 1, great sciatic nerve of the right side ; 2, lesser sciatic nerve ; 2’, its muscular
branches to the gluteus maximus (right side) ; 2”, cutaneous branches to the buttock (left
side) ; 3, continuation of the nerve as posterior middle cutaneous of the thigh ; 3, internal
and external cutaneous branches ; 4, 4, inferior pudendal branch ; 4’, network of this and
the perineal nerves on the scrotum ; 5, right pudic nerve; 6, superior branch or nerve
to the penis; 7, the external superficial perineal branch ; 7’, the internal superficial

perineal branch; 8, musculo-bulbal branches ; 9, hemorrhoidal or cutaneous anal branches ;
10, cutaneous branch of the fourth sacral nerve.

Some of the branches of this nerve end in the external sphincter and in the
adjacent skin of the anus; others reach the skin in front of that part, and

communicate with the inferior pudendal branch of the small sciatic nerve, and
with the superficial perineal nerves.

SummAry.—The pudic nerve supplies the perineum, the penis, and
part of the scrotum, also the urethral and anal muscles in the male ; and
the clitoris, labia, and other corresponding parts in the female. It

communicates with the inferior pudendal branch of the small sciatic
nerve.

THE SMALL SCIATIC NERVE 613

Small Sciatic Nerve.

The small sciatic nerve (nervus ischiadicus minor) is chiefly a
cutaneous nerve, supplying the integument of the lower part of
the buttock, the back of the thigh, and upper part of the calf
of the leg; it furnishes also branches to one muscle—the gluteus
maximus.

This nerve is formed by the union of two or more nervous cords,
derived from the lower and back part of the sacral plexus. Arising
below the pyriform muscle, it descends beneath the gluteus maximus,
and at the lower border of that muscle comes into contact with the
fascia lata. Continuing its course downwards along the back of the
limb, it perforates the fascia a little below the knee.

Fig. 374.—Drerp NERVES IN THE
GLUTEAL AND INFERIOR PuDENDAL
Rearons (after Hirschfeld and Le-
veillé). 4

a, back part of the great trochanter ;
6, tensor vagine femoris muscle ; ¢,
tendon of the obturator internus muscle
near its insertion ; d, upper part of the
vastus externus; ¢, coccyx ; f, gracilis
muscle ; between f and d, the adductor
magnus, semitendinosus, and biceps
muscles ; * placed at the meeting of the
crura penis above the urethra; 1,
placed upon the ilium close above the
sacro-sciatic notch, marks the superior
gluteal nerve, and on the divided parts
of the gluteus medius muscle, the supe-
rior branch of the nerve; 1’, on the
surface of the gluteus minimus muscle,
the inferior branch of the nerve; 1",
branch of the nerve to the tensor vaginz
femoris; 2, sacral plexus and great
sciatic nerve ; 2’, muscular twig from
the plexus to the pyriformis ; 2", mus-
cular branches to the gemellus superior
and obturator internus ; 3, lesser sciatic
nerve; 3, placed on the upper and
lower paris of the divided gluteus
maximus, the inferior gluteal muscular branches of the lesser sciatic nerve; 3”, the
cutaneous branches of the same nerve winding round the lower border of the gluteus
maximus; 4, the continuation of the lesser sciatic nerve as posterior cutaneous nerve of
the thigh ; 4’, inferior pudendal branch of the lesser sciatic ; 5, placed on the lower part
of the sacral plexus, points to the origin of the pudic nerve ; 6, its perineal division with
its muscular branches ; 6’, anterior or superior superficial perineal branch ; 6”, posterior
or inferior superficial perineal ; + +, distribution of these nerves and the inferior puden-
dal on the scrotum ; 7, dorsal nerve of the penis.

BRANCHES.—A. The inferior gluteal branches, given off under the gluteus
maximus, supply the lower part of that muscle.—A distinct gluteal branch com-
monly proceeds from the sacral plexus to the upper part of the muscle.

B. The cutaneous branches of the nerve principally emerge from beneath the
lower border of the gluteus maximus, arranged in an external and an internal
set. Others appear lower down.

a. The internal are mostly distributed to the skin of the inner side of the
thigh at the upper part. One branch, however, which is much larger than the
rest, is distinguished as the inferior pudendal,

614 THE SACRAL NERVES.

The inferior pudendal branch turns forwards below the ischial tuberosity to
reach the perineum. Its filaments then extend forwards to the front and outer
part of the scrotum, and communicate with one of the superficial perineal nerves,

Fig. 375.

Fig. 375.—Posterror Curanrous Nerves or THE Hiv anv TuIGu
(after Hirschfeld and Leveillé). +

a, gluteus maximus muscle partially uncovered by the removal of a part of the fascia
lata, and divided at its inferior part to show the lesser sciatic nerve; 0, fascia lata over
the glutei muscles and the outer part of the hip ; ¢, d, part of the semitendinosus, biceps,
and semimembranosus muscles exposed by the removal of the fascia; e, gastrocnemius;
J, coccyx ; g, internal branches of the saphena vein ; 1, iliac cutaneous branches of the
ilio-inguinal and ilio-hypogastric nerves ; 2, cutaneous iliac branches of the last inter-
costal ; 3, posterior twigs of the external cutaneous nerve of the thigh ; 4, lesser sciatic
nerve issuing from below the gluteus maximus muscle ; 4’, its muscular branches; 4",
its cutaneous gluteal branches ; 5, posterior middle cutaneous continued from the lesser
sciatic ; 5’, 5’, its inner and outer branches spreading on the fascia of the thigh ; 6, 6, its
terminal branches descending on the calf of the leg; 7, posterior tibial and fibular
nerves separating in the popliteal space; 8, lower posterior divisions of the sacral and
coccygeal nerves ; 9, inferior pudendal nerve.

Fig. 376.—Dzrp Posterior Nerves oF THE Hip anp Tuiacu.
c=)

(after Hirschfeld and Leveillé). +
a, gluteus medius muscle; 0, gluteus maximus; c, pyriformis; d, placed on the

THE GREAT SCIATIC NERVE. 615

trochanter major, points to the tendon of the obturator internus ; e, upper part of the
femoral head of the biceps ; f, semitendinosus ; g, semimembranosus ; h, gastrocnemius ;
2, popliteal artery; 1, placed on the gluteus minimus muscle, points to the superior
gluteal nerves; 2, inferior gluteal branches of the lesser sciatic ; 3, placed on the greater
sacro-sciatic ligament, points to the pudic nerve ; 3’, its farther course; 4, inferior
pudendal ; 5, placed on the upper divided part of the semitendinosus and biceps, points
to the posterior middle cutaneous nerve of the thigh; 6, great sciatic nerve, 6’, 6’, some
of its muscular branches to the flexors; 7, internal popliteal nerve; 7’, its muscular
or sural branches; 8, external popliteal nerve; 8’, its external cutaneous branch ;
9, communicating tibial ; 9’, communicating peroneal branch to the external saphenous
nerve.

In the female, the inferior pudendal branch is distributed to the external labium
pudendi.

b. The external cutaneous branches, two or three in number, turn upwards in a
retrograde course to the skin over the lower and outer part of the great gluteal
muscle. In some instances one takes a different course, descending and ramify-
ing in the integuments on the outer side of the thigh nearly to the middle.

c. Of the lower branches some small cutaneous filaments pierce the fascia of
the thigh above the popliteal space. One of these, arismg somewhat above the
knee-joint, is prolonged over the popliteal region to the upper part of the leg.

Of the terminal twigs, perforating the fascia lata opposite the lower part ot the
popliteal space, one accompanies the short saphenous vein beyond the middle of
the leg, and others pass into the integument covering the inner and outer heads
of the gastrocnemius muscle, Its terminal cutaneous branches communicate with
the short saphenous nerve,

Great Sciatic Nerve.

The great sciatic nerve (nervus ischiadicus major), the largest nerve
in the body, supplies the muscles at the back of the thigh, and by its
branches of continuation gives nerves to all the muscles below the knee
and to the greater part of the integument of the leg and foot. The
several joints of the lower limb receive filaments from it and its branches.

This large nerve is continued from the lower end of the sacral plexus.
It escapes from the pelvis through the great sacro-sciatic foramen,
below the pyriformis muscle, and reaches down below the middle of the
thigh, where it separates into two large divisions, named the zternal
and external popliteal nerves. At first it lies in the hollow between the
great trochanter and the ischial tuberosity, covered by the gluteus
maximus and resting on the gemelli, obturator internus, and quadratus
femoris muscles, in company with the small sciatic nerve and the sciatic
artery, and receiving from that artery a branch which runs for some
distance in its substance. Lower downit rests on the adductor magnus,
and is covered behind by the long head of the biceps muscle.

The bifurcation of the sciatic nerve may take place at any point intermediate
between the sacral plexus and the lower part of the thigh; and, occasionally, it
is found to occur even within the pelvis, a portion of the pyriformis muscle being
interposed between the two great. divisions of the nerve,

BRANCHES OF THE TRUNK.—In its course downwards, the great
sciatic nerve supplies offsets to some contiguous parts, viz., to the hip-
joint, and to the muscles at the back of the thigh.

a. The articular branches are derived from the upper end of the nerve, and
enter the capsular ligament of the hip-joint, on the posterior aspect. They some-
times arise from the sacral plexus, Z

616 NERVES OF THF LOWER LIMB.

b, The muscular branches are given off under cover of the biceps muscle ; they
supply the flexors of the leg, viz., the biceps, semitendinosus, and semimembra-
nosus, <A branch is likewise given to the adductor magnus.

Internal Popliteal Nerve.—The internal popliteal nerve, the
larger of the two divisions of the great sciatic nerve, following the
same direction as the parent trunk, continues along the middle of the
popliteal space to the lower border of the popliteus muscle, beneath
which point the continuation of the trunk
receives the name of posterior tebial. The in-
ternal popliteal nerve lies at first at a consider-
able distance from the popliteal artery, at the
outer side and nearer to the surface; but,
from the knee-joint downwards, the nerve,
continuing a straight course, is close behind
the artery, and then crosses it rather to the
inner side.

Fig. 377.—Posterror Curanrous Nerves or THE Lee
(grom Sappey after Hirschfeld and Leveillé).

1, internal popliteal division of the great sciatic nerve ;
2, branch to the internal part of the gastrocnemius
muscle; 3, 4, branches to the external part and plan-
taris ; 5, communicating branch to the external saphe-
nous nerve; 6, external popliteal nerve ; 7, cutaneous
branch ; 8, communicating branch descending to unite
with that from the internal popliteal in, 9, the external
saphenous nerve; 10, calcaneal branch from this nerve ;
11, calcaneal and plantar cutaneous branches from the
posterior tibial nerve ; 12, internal saphenous nerve ;
13, posterior branches of this nerve.

BrANCHES.—The internal popliteal nerve
supplies branches to the knee-joint and to
the muscles of the calf of the leg, and also
part of a cutaneous branch, the external or
short saphenous nerve.

Articular Nerves.—The articular branches are
generally three in number ; two of these accompany
the upper and lower articular arteries of the inner
side of the knee-joint, the third follows the middle
or azygos artery. These nerves pierce the liga-
mentous tissue of the joint.—The upper one is often
wanting.

Muscular Branches.—The muscular branches
of the internal popliteal nerve arise behind the
knee-joint, while the nerve is between the heads
of the gastrocnemius muscle.

a. The nerves to the gastrocnemius consist of two branches, which separate,
one to supply each part of the muscle.

b. The small nerve of the plantaris muscle is derived from the outer of the
branches just described, or directly from the main trunk (internal popliteal).

c. The soleus receives a branch of considerable size, which enters the muscle on
the posterior aspect after descending to it in front of the gastrocnemius.

d, The nevve of the popliteus muscle lies deeper than the preceding branches,
and arises somewhat below the joint; it descends along the outer side of the
popliteal vessels, and, after turning beneath the lower border of the muscle,
enters the deep or anterior surface,

THE POSTERIOR TIBIAL NERVE. 617

External or short saphenous nerve.—The cutaneous branch of the internal
popliteal nerve (ramus communicans tibialis) descends along the leg beneath the
facia, resting on the gastrocnemius, in the furrow between the heads of the
muscle, to about midway between the knee and the foot. Here it perforates the
fascia, and a little lower down is usually joined by a branch from the external
popliteal nerve (communicans peronei). After receiving this communicating
branch, the external saphenous nerve descends beneath the integument near the
outer side of the tendo Achillis in company with the short saphenous vein, and
turns forwards beneath the outer malleolus to end in the skin at the side of the
foot and on the little toe. On the dorsum of the foot this nerve communicates
with the musculo-cutaneous nerve.

In many cases, the external saphenous nerve supplies the outer side of the
fourth toe, as well as the little toe. The union between the saphenous nerve
and the branch of the external popliteal nerve occurs in some cases higher than
usual, occasionally even at or close to the popliteal space. It sometimes happens
that the communication between the nerves is altogether wanting ; in which
case the cutaneous nerve to the foot is generally continued from the branch of
the internal popliteal nerve.

Posterior Tibial Nerve.—The internal popliteal nerve receives
the name of posterior tibial at the lower margin of the popliteus muscle.
It passes down the leg with the posterior tibial artery, lying for a short
distance at the inner side of the vessel and afterwards at the outer
side ; the artery inclining inwards from its origin while the nerve
continues its straight course. In the interval between the inner mal-
leolus and the heel, it divides into the two plantar nerves (internal
and external). The posterior tibial nerve, like the accompanying
vessels, is covered at first by the muscles of the calf of the leg, after-
wards only by the integument and fascia, and it rests upon the deep-
seated muscles.

LATERAL BRANCHES.—The deep muscles on the back of the leg and
the integument of the sole of the foot receive branches from the poste-
rior tibial nerve in its course along the leg.

a. The muscular branches emanate from the upper part of the nerve, either
separately or by a common trunk ; and one is distributed to each of the deep
muscles, viz., the tibialis posticus, the long flexor of the toes, and the long flexor
of the great toe. The branch which supplies the last-named muscle runs along
the peroneal artery before penetrating the muscle.

b, A calcanco-plantar cutaneous branch is furnished from the posterior tibial
nerve ; the plantar part perforates the internal annular ligament, and ramifies
in the integument at the imner side of the sole of the foot, and beneath
the heel.

Internal Plantar Nerve.—The internal plantar, the larger of the
two nerves to the sole of the foot, into which the posterior tibial divides,
accompanies the internal or smaller plantar artery, and supplies nerves
to both sides of the three inner toes, and to one side of the fourth.
From the point at which it separates from the posterior tibial nerve,
it is directed forwards under cover of the first part of the abductor
of the great toe, and passing between that muscle and the short
flexor of the toes, it gives off the internal cutaneous branch for the
great toe, and divides opposite the middle of the foot into three digital
branches. The outermost of these branches communicates with the
external plantar nerve.

618 NERVES OF THE LOWER LIMB.

a. Small muscular branches are supplied to the abductor pollicis and flexor
brevis digitorum.

b. Small plantar cutaneous branches perforate the plantar fascia to ramify in
the integument of the sole of the foot.

c. The digital branches are named numerically from within outwards: the
three outer pass from under cover of the plantar fascia near the clefts between
the toes. The first or innermost branch continues single, but the other three
bifurcate to supply the adjacent sides of two toes. These branches require
separate notice.

The first digital branch is that destined for the inner side of the great toe ; it
becomes subcutaneous farther back than the others, and sends off a branch to

the flexor brevis pollicis.

Fig. 378.—Superrician AnD Derr DistRIBUTION oF
THE PiLantar NervES (after Hirschfeld and Le-
veillé, slightly modified). (A. 1.) 4

The flexor communis brevis, the abductor pollicis
and abductor minimi digiti, a part of the tendons
of the flexor communis longus, together with the lum-
bricales muscles, have been removed so as to bring
into view the transversus and interossei in the middle
of the foot.

a, upon the posterior extremity of the flexor com-
munis brevis, near which, descending over the heel,
are seen ramifications of the calcaneal branch of
the posterior tibial nerve; 6, abductor pollicis; ¢,
tendon of the flexor communis longus divided close to
the place where it is joined by the flexor accessorius ;
d, abductor minimi digiti; e, tendon of the flexor
longus pollicis between the two portions of the flexor
brevis pollicis ; 1, internal plantar nerve giving some
twigs to the abductor pollicis, and 1’, a branch to the
flexor communis brevis, cut as it lies on the acces-
sorius; 2, inner branch of the internal plantar nerve
giving branches to the abductor pollicis, flexor brevis
pollicis, and forming, 2’, the internal cutaneous of
the great toe ; 3, continuation of the internal plantar
nerve, dividing subsequently into three branches,
which form, 3’, 3’, 3’, the collateral plantar cutaneous
nerves of the first and second, second and third, and
third and fourth toes ; 4, the external plantar nerve ;
4', its branch to the abductor minimi digiti; 5, twig
of union between the plantar nerves ; 6, superficial
branch of the external plantar nerve ; subsequently
dividing into 6’, 6’, the collateral cutaneous nerves of
the fourth and fifth toes and the external nerve of the fifth; 7, deep branch of the
external plantar nerve giving twigs to the adductor pollicis, the interossei, the trans-
versalis, and to the third and fourth lumbricales muscles.

The second branch having reached the interval between the first and second
metatarsal bones, furnishes a small twig to the first Jwmbricalis muscle, and
bifurcates behind the cleft between the great toe and the second to supply their
contiguous sides.

The third digital branch, corresponding with the second interosseous space,
gives a slender filament to the second lumbricalis muscle, and divides in a manner
similar to that of the second branch into two offsets for the sides of the second
and third toes.

The fourth digital branch distributed to the adjacent sides of the third and
fomth toes, receives a communicating branch from the external plantar

nerve.
Along the sides of the toes, cutaneous and articular filaments are given from

THE PLANTAR NERVES, 619

these digital nerves ; and, opposite the ungual phalanx, each sends a dorsal branch
to the pulp beneath the nail, and then runs on to the ball of the toe, where it is
distributed like the nerves of the fingers.

External Plantar Nerve.—The external plantar nerve completes
the supply of digital nerves to the toes, furnishing branches to the
little toe and half the fourth: it also gives a deep branch of con-
siderable size, which is distributed to several of the short muscles in
the sole of the foot. There is thus a great resemblance between the
distribution of this nerve in the foot and that of the ulnar nerve in
the hand.

The external plantar nerve runs obliquely forwards towards the outer
side of the foot, along with the external plantar artery, between the
flexor brevis digitorum and the flexor accessorius, as far as the interval
between the former muscle and the abductor of the little toe. Here it
divides into a superficial and a deep branch, having previously furnished
offsets to the flexor accessorius and the abductor minimi digiti.

a. The superficial portion separates into two digital branches, which have the
same general arrangement as the digital branches of the internal plantar nerve.
They are distributed thus.

Digital branches.—One of the digital branches continues undivided, and runs
along the outer side of the little toe : it is smaller than the other, and pierces the
plantar fascia further back. The short flexor muscle of the little toe, and occa-
sionally one or two intcrosseous muscles of the fourth metatarsal space receive
branches from this nerve.

The larger digital branch communicates with an offset from the internal
plantar nerve, and bifurcates near the cleft between the fourth and fifth toes to
supply one side of each.

b. The deep or muscular branch of the external plantar nerve dips into the sole
of the foot with the external plantar artery, under cover of the tendons of the
flexor muscles and the adductor pollicis, and terminates in numerous branches
for the following muscles :—alli the interossei (dorsal and plantar) except occa-
sionally one or both of those in the fourth space, the two outer lumbricales, the
adductor pollicis, and the transversalis pedis,

SUMMARY OF THE INTERNAL PopLitEAL NERVE.—This nerve sup-
plies all the muscles of the back of the leg and sole of the foot, and the
integument of the plantar aspect of the toes, the sole of the foot, and
in part that of the leg.

External Popliteal Nerve.—This nerve descends obliquely along
the outer side of the popliteal space, lymg close to the biceps muscle.
Continuing downwards over the outer part of the gastrocnemius
muscle (between it and the biceps) below the head of the fibula, the
nerve turns round that bone, passing between it and the peroneus
longus muscle, and then divides into the anterior tibial and the
musculo-cutaneous Nerves.

LATERAL BRANCHES.—Some articular and cutaneous branches are
derived from the external popliteal nerve before its final division.

Articular nerves.—The articular branches are conducted to the outer side of
the capsular ligament of the knee-joint by the upper and lower articular arteries
of that side. They sometimes arise together, and the upper one occasionally
springs from the great sciatic nerve before the bifurcation.

From the place of division of the external popliteal nerve, a recurrent articular
nerve ascends through the tibialis anticus muscle with the recurrent artery to
reach the fore part of the knee-joint, ~

620 NERVES OF THE LOWER LIMB.

Cutaneous nerves.—The cutaneous branches, two or three in number, supply
the skin on the back part and outer side of the leg.

Fig. 379.—CuTangous NERVES OF THE
OvuTER Sipe oF THE Lue anv Foor
(from Sappey after Hirschfeld and
Leveille). 2
1, external popliteal nerve ; 2, its

external cutaneous branch ; 3, communi-

cating branch which unites with 4, that
from the internal popliteal, in 5, the ex-
ternal saphenous nerve; 6, calcaneal

branch of the external saphenous; 7,

external dorsal digital branch to the fifth

toe ; 8, collateral dorsal digital branch
of the fourth and fifth toes ; 9, musculo-
cutaneous nerve ; 10, its cutaneous
branches ; 11, loop of union with the
external saphenous ; 12, union between
its outer and inner branches; 18, an-
terior tibial nerve, shown by the removal
of a part of the muscles, and giving
muscular branches superiorly ; 14, its
terminal branch emerging in the space
between the first and second toes, where
it gives the collateral dorsal digital

branches to their adjacent sides; 15,

branches to the peronei muscles.

The peroneal communicating branch
@. communicans fibularis), which
joins the short saphenous nerve below
the middle of the back of the leg, is
the largest of these nerves. In some
instances, it continues a separate
branch and its cutaneous filaments
reach down to the heel or on to the
outside of the foot.

Another cutaneous branch extends
along the outer side of the leg to
the middle or lower part, sending
offsets both backwards and for-
wards.

Musculo-Cutaneous Nerve.—The musculo-cutaneous (peroneal)
nerve descends between the peronei muscles and the long extensor of
the toes, and reaches the surface by perforating the fascia in the lower
part of the leg on the anterior aspect. It then divides into two branches,
distinguished as external and internal, which proceed to the toes. The
two branches sometimes perforate the fascia at a different height.

(a) Muscular branches are given to the peroneus longus and peroneus brevis.

(b) Cutancous branches given off before the final division are distributed to the
lower part of the leg.

(c) The internal branch of the musculo-cutaneous nerve, passing forwards
along the dorsum of the foot, furnishes one branch to the inner side of the great
toe, and others to the contiguous sides of the second and third toes. It gives
other offsets, which extend over the inner ankle and side of the foot. This nerve
communicates with the long saphenous nerve on the inner side of the foot, and
with the anterior tibial nerve between the first and second toes,

THE MUSCULO-CUTANEOUS NERVE. 621

(d) The external branch, larger than the internal one, descends over the foot
towards the fourth toe, which, together with the contiguous borders of the third
and fifth toes, it supplies with branches. Cutaneous nerves, derived from this
branch, spread over the outer ankle and the outer side of the foot, where they are
connected with the short saphenous nerve.

Fig. 380. — View oF THE DISTRIBUTION OF THE
BRANCHES OF THE EXTERNAL PopiirEAL NERVE IN
THE Front oF THE Lec anp Dorsum OF THE Foot
(after Hirschfeld and Leveillé).

The upper part of the peroneus longus muscle has
been removed, the tibialis anticus, the long extensor of
the great toe and the peroneus longus have been drawn
separate in the leg by hooks marked a, 6, and c, and
the tendons of the extensor muscles have beer removed
in the dorsum of the foot, to show the deeper seated
nerves; 1, the external popliteal or peroneal nerve
winding round the other part of the fibula; 1’, its
recurrent articular branches exposed by the dissection
of the upper part of the tibialis anticus muscle; 2, 2,
the musculo-cutaneous nerve ; 2’, 2’, twigs to the long
and short peroneal muscles ; 3, internal branch of the
musculo-cutaneous nerve; 3, 3’, its dorsal digital
branches to the inside of the great toe, and to the
adjacent sides of the second and third toes; 4, the
external branch ; 4’, 4’, its dorsal digital branches to
the adjacent sides of the third and fourth toes, and in
part to the space between the fourth and fifth toes ;
5, the external saphenous nerve descending on the
outer border of the foot, and uniting at two places
with the outer branch of the musculo-cutaneous ; 5’,
its branch to the outer side of the fifth toe ; 6, placed
on the upper part of the extensor communis digitorum,
marks the anterior tibial nerve passing beneath the
muscles ; 6, placed further down on the tendon of the
tibialis anticus, points to the ‘nerve as it crosses to
the inside of the anterior tibial artery ; 6’, its muscular
branches in the lez; 6", on the tendon of the extensor
longus pollicis points to the anterior tibial nerve after
it has passed into the foot behind that tendon; 7,
its inner branch uniting with a twig of the musculo-
cutaneous, and giving the dorsal digital nerves to the
adjacent sides of the first and second toes ; 8, distri-
bution of its outer branch to the extensor brevis digi-
torum and tarsal articulations.

The dorsal digital nerves are continued on to
the last phalanges of the toes.

The number of toes supplied by each of the two
divisions of the musculo-cutaneous nerve is liable to vary ; together these nerves
commonly supply all the toes on the dorsal aspect, excepting the outer side of
the little toe, which receives a branch from the short saphenous nerve, and the
adjacent sides of the great toe and the second toe, to which the anterior tibial
nerve is distributed : with this latter branch, however, it generally communicates.

Anterior Tibial Nerve.—The anterior tibial (interosseous nerve),
commencing between the fibula and the peroneus longus, inclines ob-
liquely beneath the long extensor of the toes to the fore part of the
interosseous membrane, and there comes into contact with the anterior
tibial vessels, and with those vessels it descends to the front of the
ankle-joint, where it divides into an external and an internal branch.

622 NERVES OF THE LOWER LIMB,

The nerve first reaches the outer side of the anterior tibial artery,
above the middle of the leg ; and, after crossing in front of that vessel
once or oftener, lies to the outer side of it at the bend of the ankle.

(a) Muscular branches.—In its course along the leg, the anterior tibial nerve
gives slender filaments to the muscles between which it is placed, namely, the
tibialis anticus, the long extensor of the toes, and the special extensor of the
great toe.

(>) The external branch of the anterior tibial nerve turns outwards over the
tarsus beneath the’short extensor of the toes ; and, having become enlarged (like
the posterior interosseous nerve on the wrist) terminates in branches which
supply the short extensor muscle, and likewise the articulations of the foot.

(c) The internal branch, continuing onwards in the direction of the anterior
tibial nerve, accompanies the dorsal artery of the foot to the first interosseous
space, and ends in two branches, which supply the integument on the neighbouring
sides of the great toe and the second toe on their dorsal aspect. It communi-
cates with the internal division of the musculo-cutaneous nerve.

SUMMARY OF THE EXTERNAL PopiireaL Nerve.—This nerve sup-
plies, besides articular branches to the knee, ankle, and foot, the peronei
muscles, extensor muscles of the foot, also the integument of the front
of the leg and dorsum of the foot. It gives the ramus communicans
fibularis to the short saphenous branch of the internal popliteal nerve,
and communicates with the long saphenous nerve.

SYNOPSIS OF THE CUTANEOUS DISTRIBUTION OF
THE CEREBRO-SPINAL NERVES,

1. In the Head.—The face and head in front of the ear are supplied
with sensory nerves from the fifth cranial nerve. The ophthalmic
division supplies branches to the forehead, upper eyelid, and dorsum of
the nose. The superior maxillary division supplies the cheek, ala of the
nose, upper lip, lower eyelid, and the region behind the eye, over the
temporal fascia. The inferior maxillary division supplies the chin and
lower lip, the pinna of the ear on its outer side, and the integument
in front of the ear and upwards to the vertex of the head.

The head, behind the ear, is mainly supplied by the great occipital
branch of the posterior division of the second spinal nerve, but above
the occipital protuberance there is also distributed the branch from the
posterior division of the third spinal nerve ; and, in front of the area of
the great occipital nerve, is a space supplied by anterior divisions of
spinal nerves, viz., the back of the pinna of the ear, together with the
integument behind and that in front over the parotid gland, which are
supplied by the great auricular nerve ; while between the area of that
nerve and the great occipital the small occipital nerve intervenes. The
auricular branch of the pneumo-gastric nerve also is distributed on the
back of the ear.

2. In the Trunk.—The posterior divisions of the spinal nerves supply
an area extending on the back from the vertex of the skull to the buttock.
This area is narrow in the neck ; it is spread out over the back of the
scapula ; and on the buttock the distribution of the lumbar nerves
extends to the trochanters.

The area supplied by the cervical plexus, besides extending upwards, as
already mentioned, on the lateral part of the skull, stretches over the

CUTANEOUS DISTRIBUTION OF THE NERVES. 623

front and sides of the neck, and the upper part of the shoulder and
breast.

The area of the anterior divisions of the dorsal and first lumbar
nerves meets superiorly with that of the cervical plexus, and posteriorly
with that of the posterior divisions of dorsal and lumbar nerves. It
passes down over the haunch and along by the outer part of Poupart’s
ligament, and includes part of the scrotum and a small portion of the
integument of the thigh internal to the saphenous opening.

The perineum and penis are supplied by the pudic nerve; the
scrotum by branches of the pudic, inferior pudendal, and ilio-inguinal
nerves.

3. In the Upper limb.—The shoulder, supplied superiorly by the
cervical plexus, receives its cutaneous nerves inferiorly as far as the
insertion of the deltoid from the circumflex nerve.

The arm internally is supplied by the intercosto-humeral nerve and
the nerve of Wrisberg. The inner and anterior part is supplied by
the internal cutaneous nerve ; and the posterior and outer part by the
internal and external branches of the musculo-spiral nerve.

The forearm, anteriorly and on the outer side, is supplied by the
external cutaneous ; on its outer and posterior aspect, superiorly by the
external cutaneous branches of the musculo-spiral, and inferiorly by the
radial branch of the same nerve. On the inner side, both in front and
behind, is the internal cutaneous nerve, and inferiorly are branches of
the ulnar.

On the back of the hand are the radial and ulnar nerves, the radial
supplying about three fingers and a half or less, and the ulnar one and
a half or more.

On the front of the hand, the median nerve supplies three fingers and
a half, and the ulnar one and a half. In the palm is a branch of the
median given off above the wrist. On the ball of the thumb are branches
of the musculo-cutaneous, median, and radial nerves.

4. In the Lower limb.—The buttock is supplied from above by the
cutaneous branches of the posterior divisions of the lumbar nerves,
with the ilio-hypogastric and lateral branches of the last dorsal nerves ;
internally by the posterior divisions of the sacral nerves ; externally by
the posterior branch of the external cutaneous nerve proceeding from
the front ; and inferiorly by branches of the small sciatic nerve proceed-
ing from below.

The thigh is supplied externally by the external cutaneous nerve ;
posteriorly, and in the upper half of its inner aspect, by the small
sciatic ; anteriorly, and in the lower ,half of the inner aspect, by the
middle and internal cutaneous.

The /eg is supplied posteriorly by the small sciatic and short
saphenous nerves ; internally by the long saphenous and branches of
the internal cutaneous of the thigh ; and outside and in front by cuta-
neous branches of the external popliteal nerve and by its musculo-
cutaneous branch.

On the dorsum of the foot are the branches of the musculo-cutaneous,
supplying all the toes with the exception of the adjacent sides of the
first and second, which are supplied by the anterior tibial, and the
outer side of the little toe, which, with the outer side of the foot, is
supplied by the short saphenous nerve. The long saphenous is the
cutaneous nerve on the inner side of the foot.

624 MUSCULAR DISTRIBUTION OF THE NERVES.

The sole of the foot is supplied by the plantar nerves. The internal
plantar nerve gives branches to three toes and a half; the external to
the remaining one toe and a half.

SYNOPSIS OF THE MUSCULAR DISTRIBUTION OF THE CEREBRO-
SPINAL NERVES.

1. To Muscles of the Head and Fore Part of the Neck.

The muscles of the orbit are mostly supplied by the third cranial
nerve—the superior division of that nerve being distributed to the
levator palpebree and the superior rectus muscles ; and the inferior
division to the inferior and internal recti and the inferior oblique.
The superior oblique muscle is supplied by the fourth nerve, the ex-
ternal rectus by the sixth; while the tensor tarsi has no special nerve
apart from those of the orbicularis palpebrarum, which are derived
from the facial.

The superficial muscles of the face and scalp, which are associated in
their action as a group of muscles of expression, together with the
buccinator muscle, are supplied by the portio dura of the seventh
cranial nerve; the retrahens auriculam and occipitalis muscles being
supplied by its posterior auricular branch.

The deep muscles of the face, employed in mastication, viz., the tem-
poral, masseter, and two pterygoid muscles are supplied by the inferior
maxillary division of the fifth cranial nerve.

Muscles above the hyoid bone-—The mylo-nyoid muscle and anterior
belly of the digastric are supplied by a special branch of the inferior
maxillary division of the fifth cranial nerve ; the posterior belly of the
digastric muscle, and the stylo-hyoid, are supplied by branches of the
portio dura. The genio-hyoid and the muscles of the tongue receive
their nervous supply from the hypoglossal nerve.

The muscles ascending to the hyoid bone and laryna, viz., the sterno-
hyoid, omo-hyoid, and sterno-thyroid, are supplied from the ramus
descendens noni and its loop with the cervical plexus, while the thyro-
hyoid muscle receives a separate twig from the ninth nerve.

The laryna, pharynz, and soft palate-—The crico-thyroid muscle is
supplied by the external laryngeal branch of the pneumo-gastric nerve,
and the other intrinsic muscles of the larynx by the recurrent laryngeal.
The muscles of the pharynx are supplied principally by the pharyngeal
branch of the pneumo-gastric; the stylo-pharyngeus, however, is sup-
plied by the glosso-pharyngeal nerve. Of the muscles of the soft palate
unconnected with the tongue or pharynx, the tensor palati receives its
nerve from the otic ganglion (which also supplies the tensor tympani) ;
the levator palati gets a twig (Meckel) from the posterior palatine branch
of the spheno- palatine ¢ g anglion, and the azygos uvule is probably sup-
plied from the same source.

2. To Muscles belonging exclusively to the Trunk, and Muscles
ascending to the Skull.

All those muscles of the back which are unconnected with the upper
limb, viz., the posterior serrati, the splenius, complexus, erector opin
and the muscles more deeply placed, receive their supply from the
posterior divisions of the spinal nerves.

SYNOPSIS OF MUSCULAR DISTRIBUTION OF NERVES. 625

The sferno-mastoid is supplied by the spinal accessory nerve and a
twig of the cervical plexus coming from the second cervical nerve.

The rectus capitis anticus major and minor are supplied by twigs from
the upper cervical nerves ; the longus colli and scaleni muscles by twigs
from the lower cervical nerves.

The muscles of the chest, viz., the intercostals, subcostals, levatores
costarum, and triangularis sterni, are supplied by the intercostal
nerves.

The obligqui, transversus, and rectus of the abdomen are supplied by
the lower intercostal nerves ; and the oblique and transverse muscles
also get branches from the ilio-inguinal and ilio-hypogastric nerves.
The cremaster muscle is supplied by the genital branch of the genito-
crural nerve.

The quadratus lumborum (like the psoas) receives small branches
from the lumbar nerves before they form the plexus.

The diaphragm receives the phrenic nerves from the fourth and fifth
cervical nerves, and likewise sympathetic filaments from the plexuses
round the phrenic arteries.

The muscles of the urethra and penis are supplied by the pudic nerve ;
the levator and sphincter ani by the pudic and by the fourth and fifth
sacral and coccygeal nerves ; and the coccyyeus muscle by the three
last-named nerves.

3. To muscles attaching the upper limb to the trunk.—The
trapezius and the sterno-cleido-mastoid receive the distribution of the
spinal accessory nerve, and, in union with it, filaments from the cervical

lexus.

The latissimus dorsi receives the long subscapular nerve.

The rhomboidet are supplied by a special branch from the anterior
division of the fifth cervical nerve.

The levator anguli scapule is supplied by branches from the anterior
division of the third cervical nerve, and sometimes partly also by the
branch to the rhomboid muscles.

The serratus magnus has a special nerve, the posterior thoracic,
derived from the fifth and sixth cervical nerves.

The swbclavius receives a special branch from the place of union of
the fifth and sixth cervical nerves.

The pectorales are supplied by the anterior thoracic branches of the
brachial plexus, the larger muscle receiving filaments from both these
nerves, and the smaller from the inner only.

4, To muscles of the upper limb.—/uscles of the shoulder —The
supraspinatus and infraspinatus are supplied by the suprascapular nerve ;
the subscapularis by the two smaller subscapular nerves ; the teres major
by the second subscapular, and the deltoid and teres minor by the cir-
cumflex nerve. :

Posterior muscles of the arm and forearm.—The triceps, anconeus, '
supinator longus, and extensor carpi radialis longior are supplied by
direct branches of the musculo-spiral nerve ; while the extensor carpi
radialis brevior and the other extensor muscles in the forearm receive
their branches from the posterior interosseous division of that nerve.

Anterior muscles of the arm and forearm.—The coraco-brachialis,
biceps, and brachialis anticus are supplied by the musculo-cutaneous

nerve ; the brachialis anticus likewise generally receives a twig from
VoL. I. 8S

626 SYNOPSIS OF NERVE DISTRIBUTION.

the musculo-spiral nerve. The muscles in front of the forearm are
supplied by the median nerve, with the exception of the flexor carpi
ulnaris and the ulnar half of the flexor profundus digitorum, which are
supplied by the ulnar nerve, and the supinator longus, which is supplied
by the musculo-spiral.

Muscles of the hand.—The abductor and opponens pollicis, the outer
half of the flexor brevis pollicis, and the two outer lumbricales muscles,
are supplied by the median nerve: all the other muscles receive their
nerves from the ulnar.

5. To muscles of the lower limb.—Posterior muscles of the hip and
thigh.—The gluteus maximus is mainly supplied by the small sciatic
nerve, and receives at its upper part a separate branch from the sacral
plexus. The gluteus medius and minimus, together with the tensor
vagine femoris, are supplied by the gluteal nerve. The pyriformis,
gemelli, obturator internus, and quadratus femoris receive special
branches from the sacral plexus. ‘The hamstring muscles are supplied
by branches from the great sciatic nerve.

Anterior and internal muscles of the thigh—The psoas muscle is sup-
plied by separate twigs from the lumbar nerves. ‘The iliacus, quadriceps
extensor femoris, and sartorius are supplied by the anterior crural nerve.
The adductor muscles, the obturator externus and the pectineus, are
supplied by the obturator nerve, but the adductor magnus likewise
receives a branch from the great sciatic, and the pectineus sometimes
has a branch from the anterior crural.

Anterior muscles of the leg and foot—The muscles in front of the leg,
together with the extensor brevis digitorum, are supplied by the anterior
tibial nerve.

The peroneus longus and brevis are supplied by the musculo-cutaneous
nerve.

Posterior muscles of the leg—The gastrocnemius, plantaris, soleus,
and popliteus are supplied by branches from the internal popliteal
nerve ; the deep muscles, viz., the flexor longus digitorum, flexor longus
pollicis, and tibialis posticus, derive their nerves from the posterior
tibial.

Plantar muscles—The flexor brevis digitorum, the abductor and
flexor brevis pollicis, and the two inner lumbricales, are supplied by the
internal plantar nerve ; all the others, including the flexor accessorius
and interossei, are supplied by the external plantar nerve.

Ill SYMPATHETIC NERVES.

The nerves of the sympathetic system are distributed in general to all
the internal viscera, and to the coats of the blood-vessels. Some organs,
however, receive their nerves also from the cerebro-spinal system, as the
jungs, the heart, and the upper and lower parts of the alimentary
canal. (

This division of the nervous system consists of a somewhat compli-
cated collection of ganglia, cords and plexuses, the parts of which may,
for convenience, be classified in three groups, viz., the principal gang-
liated cords, the great prevertebral plexuses with the nerves proceeding
from them, and the ganglia of union with cranial nerves.

The great gangliated cords consist of two series, in each of which

THE GREAT SYMPATHETIC CORDS. 627

the ganglia are connected by interven-
ing cords. ‘These cords are placed sym-
metrically in front of the vertebral
column, and extend from the base of
the skull to the coccyx. Superiorly they
are connected with plexuses which enter
the cranial cavity, while inferiorly they
converge on the sacrum, and terminate
in a single ganglion on the coccyx. The
several portions of the cords are dis-
tinguished as cervical, dorsal, lumbar,
and sacral, and in each of these parts
the ganglia are equal in number, or
nearly so, to the vertebree on which they
lie, except in the neck, where there are
only three.

Fig. 381.—DracraAmMAtic OUTLINE OF THE Sym-
PATHETIC CORD OF ONE SIDE IN CONNECTION
WITH THE SpinaL NERVEs.

The full description of this figure will be found
at p. 568.

On the right side the following letters indicate
parts of thesympathetic nerves, viz. a, the superior
cervical ganglion, communicating with the upper
cervical spinal nerves and continued below into
the great sympathetic cord; 0, the middle cer-
vical ganglion ; c, d, the lower cervical ganglion
united with the first dorsal; d’, the eleventh
dorsal ganglion ; from the fifth to the ninth
dorsal ganglia the origins of the great splanchnic
nerve are shown; /, the lowest dorsal or upper
lumbar ganglion; ss, the upper sacral ganglion.
Tn the whole extent of the sympathetic cord, the
twigs of union with the spinal nerves are shown.

Connection of the gangliated cords
with the cerebro-spmal system. — The
ganglia are severally connected with the
spinal nerves in their neighbourhood by
means of short filaments ; each connect-
ing filament consisting of a white and a
grey portion, the former of which may
be considered as proceeding from the
spinal nerve to the ganglion, the latter
from the ganglion to the spinal nerve.
At its upper end the gangliated cord
communicates likewise with certain
cranial nerves. The main cords inter-
vening between the ganglia, like the
smaller filaments connecting the ganglia
with the spinal nerves, are composed of ,
a grey and a white part, the white being
continuous with the fibres of the spinal
nerves prolonged to the ganglia.

88 2

628 THE SYMPATHETIC NERVES AND GANGLIA.

The great prevertebral plexuses comprise three large aggrega-
tions of nerves, or neryes and ganglia situated in front of the spine, and
occupying respectively the thorax, the abdomen, and the pelvis. They
are single and median, and are named respectively the cardiac, the
solar, and the hypogastric plexus. These plexuses receive branches
from both the gangliated cords above noticed, and they constitute
centres from which the viscera are supplied with nerves.

The cranial ganglia of the sympathetic are the ophthalmic, spheno-

alatine, submaxillary, and otic, which, being intimately united with
the fifth cranial nerve, have already been described along with that
nerve. They are also more or less directly connected with the upper
end of the sympathetic gangliated cords; but it will be unnecessary to
give any special description of them in this place.

THE CERVICAL PART OF THE GANGLIATED CORD.

In the neck, each gangliated cord is deeply placed behind the sheath
of the great cervical blood-vessels, and in contact with the muscles
which immediately cover the fore part of the vertebral column. It
comprises three ganglia, the first of which is placed near the base of
the skull, the second in the lower part of the neck, and the third
immediately above the head of the first rib.

THE UPPER CERVICAL GANGLION.

This is the largest ganglion of the great sympathetic cord. It is
continued superiorly into an ascending branch, and tapers below into
the connecting cord, so as to present usually a fusiform shape; but
there is considerable variety in this respect in different cases, the
ganglion being occasionally broader than usual, and sometimes con-
stricted at intervals. It has the reddish-grey colour characteristic of
the ganglia of the sympathetic system. It is placed on the larger
rectus muscle, opposite the second and third cervical vertebree, and
behind the internal carotid artery.

Connection with spinal nerves.—At its outer side the superior cervical
ganglion is connected with the first four spinal nerves, by means of
slender cords, which have the structure pointed out in the general
description as being common to the series.

The circumstance of this ganglion being connected with so many as four spinal
nerves, together with its occasionally constricted appearance, is favourable to
the view that it may be regarded as consisting of several ganglia which have
coalesced.

Connection with cranial nerves—Small twigs connect the ganglion or
its cranial cord with the second ganglion of the pneumo-gastric, and
with the ninth cranial nerve, near the base of the skull; and another
branch, which is directed upwards from the ganglion, divides at the
base of the skull into two filaments, one of which ends in the second
(petrosal) ganglion of the glosso-pharyngeal nerve; while the other,
entering the jugular foramen, joins the ganglion of the root of the
pheumo-gastric.

Besides the branches connecting it with cranial and spinal nerves,
the first cervical ganglion gives off also the ascending branch, the
upper cardiac nerve, pharyngeal nerves, and branches to blood-vessels.

1. ASCENDING BRANCH AND CRANIAL PLEXUSES.— The ascending

BRANCHES OF THE UPPER CERVICAL GANGLION. 629

branch of the first cervical ganglion is soft in texture and of a reddish
tint, seeming to be in some degree a prolongation of the ganglion itself.
In its course to the skull, it is concealed by the internal carotid artery,
with which it enters the carotid canal in the temporal bone, and it is
then divided into two parts, which are placed one on the outer, the
other on the inner side of the vessel.

The external division distributes filaments to the internal carotid
artery, and, after communicating by means of other filaments with the
internal division of the cord, forms the carotid plecus.

Fig. 382,

Fig, 382.—Connections or THE SympatHetic NERVE THROUGH ITS CaRoTID BRancH
WITH SOME OF THE CRANIAL NERVES.

The full description of this figure will be found at p. 539. The following numbers
refer to sympathetic nerves and their connections :—6, spheno-palatine ganglion ; 7,
Vidian nerve ; 9, its carotid branch ; 10, a part of the sixth nerve, receiving twigs from
the carotid plexus of the sympathetic ; 11, superior cervical sympathetic ganglion ; 12,
its prolongation in the carotid branch; 15, anastomosing nerve of Jacobson; 16, twig
uniting it to the sympathetic.

The «nner division, rather the smaller of the two, supplies filaments
to the carotid artery, and goes to form the cavernous plexus. The
terminal parts of these divisions of the cranial cord are prolonged on
the trunk of the internal carotid, and extend to the cerebral and
ophthalmic arteries, around which they form secondary plexuses, those
on the cerebral artery ascending to the pia mater. One minute plexus
enters the eye-ball with the central artery of the retina.

It was stated by Ribes (Mem. de la Société Méd. d’Emulation, tom. viii. p. 606,)
that the cranial prolongations of the sympathetic nerve from the two sides
coalesce with one another on the anterior communicating artery,—a small gang-
lion or a plexus being formed at the point of junction ; but this connection has
not been satisfactorily made out by other observers.

Carotid plexus.—The carotid plexus, situated on the outer side of
the internal carotid artery at its second bend (reckoning from below),
or between the second and third bends, joins the fifth and sixth cranial
nerves, and gives many filaments to the vessel on which it lies.

Branches.—(a) The connection with the sixth nerve is established by means

of one or two filaments of considerable size, which are supplied to that nerve
where it lies by the side of the internal carotid artery.

630 THE SYMPATHETIC NERVES AND GANGLIA.

(v) The filaments connected with the Gasserian ganglion of the fifth nerve
proceed sometimes from the carotid plexus, at others from the cavernous.

(ec) The deep branch of the Vidian nerve passes backwards to the carotid plexus,
and after leaving the Vidian canal, lies in the cartilaginous substance which
closes the foramen lacerum medium, Valentin describes nerves as furnished to
the dura mater from the carotid plexus.

Cavernous plexus.— The cavernous plexus, named from its position
in the sinus of the same name, is placed below and rather to the inner
side of the highest turn of the internal carotid artery. Besides giving
branches on the artery, it communicates with the third, the fourth, and
the ophthalmic division of the fifth cranial nerves.

Branches.—(a) The filament which joins the third nerve comes into connec-
tion with it close to the point of division of that nerve.

(b) The branch to the fourth nerve, which may be derived from either the
cavernous or the carotid plexus, joins the nerve where it lies in the wall of the
cavernous sinus.

(ec) The filaments connected with the ophthalmic trunk of the fifth nerve are
supplied to its inner surface. One of them is continued forwards to the lenti-
cular ganglion, either in connection with or distinct from the nasal nerve.

2. PHARYNGEAL NERVES AND PLEXUS.—These nerves arise from the
inner part of the ganglion, and are directed obliquely inwards to the
side of the pharynx. Opposite the middle constrictor muscle they
unite with branches of the pneumogastric and _ glosso-pharyngeal
nerves ; and by their union with those nerves the pharyngeal plexus
is formed. Branches emanating from the plexus are distributed to the
muscles and mucous membrane of the pharynx.

3. UPPER CARDIAC NERVE.—Hach of the cervical ganglia of the
sympathetic furnishes a cardiac branch, the three being named respec-
tively the upper, middle, and lower cardiac nerves.

These branches are continued singly, or in connection, to the large
prevertebral centre (cardiac plexus) of the thorax. Their size varies
considerably, and where one branch is smaller than common, another
will be found t» be increased in size, as if to compensate for the defect.
There are some differences in the disposition of the nerves of the right
and left sides.

The upper cardiac nerve (n. cardiacus superficialis) of the right
side proceeds from two or more branches of the ganglion, with, in
some instances, an offset from the cord connecting the first two
ganglia. In its course down the neck the nerve lies behind the carotid
sheath, im contact with the longus colli muscle ; and it is placed in
front of the lower thyroid artery and the recurrent laryngeal nerve.
Entering the thorax, it passes in some cases before, in others behind
the subclavian artery, and is directed along the innominate artery to
the back part of the arch of the aorta, where it ends in the deep cardiac
plexus, a few small filaments continuing also to the front of the great
vessel. Some branches accompany the inferior thyroid artery to be dis-
tributed to the thyroid body.

In its course downwards this cardiac nerve is repeatedly connected with other
branches of the sympathetic, and with the pneumo-gastric nerve. Thus about
the middle of the neck it is joined by some filaments from the external laryngeal
nerve; and, rather lower down, by one or more filaments from the trunk of the
pneumo-gastric nerve ; lastly, on entering the chest, it joins with the recurrent
laryngeal,

THE UPPER CARDIAC NERVES. 631

Variety.—Instead of passing to the thorax in the manner described, the
superior cardiac nerve may join the cardiac branch furnished from one of the
other cervical ganglia. Scarpa describes this as the common disposition of the
nerve ; but Cruyeilhier (Anat. Descript., t. iv.) states that he has not in any case
found the cardiac nerves to correspond exactly with the figures of the “ Tabule
Neurologicze.”

The upper cardiac nerve of the left side has, while in the neck,
the same course and connections as that of the right side. But within

Fig. 382.

Fig. 383.—Connzctions oF THE CreRvicaL AND upPER DorsAL SYMPATHETIC GANGLIA
AnD NERVES ON THE LEFT SIDE.

The full description of this figure will be found at p. 558. The following numbers
refer to the sympathetic ganglia and nerves, and those immediately connected with
them :—5, pharyngeal plexus; 8, laryngeal plexus ; 13, pulmonary plexus; and to
the reader’s left, above the pulmonary artery, a part of the cardiac plexus; 24, superior
cervical ganglion of the sympathetic ; 25, middle cervical ganglion ; 26, inferior cervical
ganglion united with the first dorsal ganglion; 27, 28, 29, 30, second, third, fourth,
and fifth dorsal ganglia. F

632 THE SYMPATHETIC NERVES AND GANGLIA.

the chest it follows the left carotid artery to the arch of the aorta, and
ends in some instances in the superficial cardiac plexus, while in others
it joins the deep plexus ; and accordingly it passes either in front of or
behind the arch of the aorta.

4, BRANCHES TO BLOOD-VESSELS.—The nerves which ramify on the
arteries (nervi molles) spring from the front of the ganglion, and
twine round the trunk of the carotid artery. They are also pro-
longed on the branches of the external carotid, and form slender
plexuses upon them.

Communications with other nerves.—From the plexus on the facial artery
is derived the filament which joins the submaxillary ganglion ; and, from that on
the middle meningeal artery, twigs have been described as extending to the otic
ganglion, as well as to the gangliform enlargement of the facial nerve. Lastly,
a communication is established between the plexus on the carotid artery and the
digastric branch of the facial nerve.

Varieties.—Small ganglia are occasionally found on some of the vascular
plexuses, close to the origin of the vessels with which they are associated. Thus
lingual, temporal, and pharyngeal ganglia have been described ; and besides these
there is a larger body, the ganglion intercaroticum, placed on the inner side of
the angle of division of the common carotid artery. This body, long known to
anatomists as a ganglion, has been stated by Luschka to have a structure very
different from the nervous ganglia in general, and has been named by him the
** elandula intercarotica.”

It is described by him as presenting principally a follicular structure, similar to
that of the glandula coccygea, which he had previously discovered. It appears,
however, from the researches of Julius Arnold, that the follicular appearances
observed by Luschka, both in this instance and in the coccygeal gland, were pro-
duced by arterial glomeruli seen in section ; and that the ganglion intercaroticum
consists of numbers of those glomeruli gathered into several larger masses, and of
dense plexuses of nerves surrounding respectively the glomeruli, the masses, and the
whole structure. Within those plexuses nerve-cells are scattered, but not in very
great number. The ganglion is usually about one-fourth of an inch long; but,
according to Luschka, may be divided into small separate masses, and thus escape at-
tention, or be supposed to be absent.—(Luschka, ‘“ Anat.d. Menschen,” vol. i. 1862 ;_
and Julius Arnold, in “ Virchow’s Archiv,” June, 1865.)

MIDDLE CERVICAL GANGLION,

The middle ganglion (ganglion thyroideum), much the smallest of the
cervical ganglia, is placed on or near the inferior thyroid artery. It is
usually connected with the fifth and sixth spinal nerves, but in a some-
what variable manner. It gives off thyroid branches and the middle
cardiac nerve.

Thyroid branches.—From the inner side of the ganglion some
twigs proceed along the inferior thyroid artery to the thyroid body,
where they join the recurrent laryngeal and the external laryngeal
nerves. Whilst on the artery, these branches communicate with the
upper cardiac nerve.

The middle cardiac nerve (nervus cardiacus profundus y. magnus)
of the right side is prolonged to the chest behind the sheath of the
common carotid artery, and either in front of or behind the subclavian
artery. In the chest it lies on the trachea, where it is joined by fila-
ments of the recurrent laryngeal nerve, and it ends in the right side of
the deep cardiac plexus. While in the neck, the nerve communicates
with the upper cardiac nerve and the recurrent branch of the pneumo-
gastric.

MIDDLE AND LOWER CERVICAL GANGLIA. 633

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.

When the middle cervical ganglion is small, the middle cardiac nerve may be
found to be an offset of the inter-ganglionic cord.

LOWER CERVICAL GANGLION.

The lower or third cervical ganglion is irregular in shape, usually
somewhat flattened and round or semilunar, and is frequently united in
part to the first thoracic ganglion. Placed in a hollow between the
transverse process of the last cervical vertebra and the neck of the first
rib, it is concealed by the vertebral artery. It is connected by short
communicating cords with the two lowest cervical nerves. Numerous
branches are given off from it, among which the largest is the lower
cardiac nerve.

The lower cardiac nerve, issuing from the third cervical ganglion
or from the first thoracic, inclines inwards on the right side, behind the
subclavian artery, and terminates in the cardiac plexus behind the arch
of the aorta. It communicates with the middle cardiac and recurrent
laryngeal nerves behind the subclavian artery.

On the (eft side, the lower cardiac often becomes blended with the
middle cardiac nerve, and the cord resulting from their union terminates
in the deep cardiac plexus.

Branches to blood-vessels.—From the lowest cervical and first
dorsal ganglia a few slender branches ascend along the vertebral artery
in its osseous canal, forming a plexus round the vessel by their inter-
communications, and supplying it with offsets. This plexus is connected
with the cervical spinal nerves as far upwards as the fourth.

One or two branches frequently pass from the lower cervical ganglion
to the first dorsal ganglion in front of the subclavian artery, forming
loops round the vessel (ans Vieussenii), and supplying it with small
offsets.

THORACIC PART OF THE GANGLIATED CORD.

In the thorax the gangliated cord is placed towards the side of the
spinal column, in a line passing over the heads of the ribs. It is
covered by the pleura, and crosses the intercostal blood-vessels.

Opposite the head of each rib the cord usually presents a ganglion,
so that there are commonly twelve of these; but, from the occasional
coalescence of two, the number varies slightly. The first ganglion when
distinct is larger than the rest, and is of an elongated form ; but it is
often blended with the lower cervical ganglion. The rest are small,
generally oval, but very various in form.

Connection with the spinal nerves——The branches of connection be-
tween the spinal nerves and the ganglia of the sympathetic are usually
two in number for each ganglion ; one of these generally resembling
the spinal nerve in structure, the other more similar to the sympathetic
nerve.

BRANCHES OF THE GiNGLIA.

The branches furnished by the first five or six gangua are small, and
are distributed in a great measure ‘to the thoracic aorta, the vertebre,

634 THE SYMPATHETIC NERVES AND GANGLIA.

THORACIC NERVES AND GANGLIA. 635

Fig. 384.—Dracramuatic View oF THE SympaTHETIc Corp or THE RicET Sinz,
SHOWING ITs CONNECTIONS WITH THE PRINCIPAL CEREBRO-SPINAL NERVES AND THE

Martn Preaortic Purxusrs. 4

Cercpro-spinal Nerves.—VI, a portion of the sixth cranial nerve as it passes through
the cavernous sinus, receiving two twigs from the carotid plexus of the sympathetic
nerve; O, ophthalmic ganglion connected by a twig with the carotid plexus; M, con-
nection of the spheno-palatine ganglion by the Vidian nerve with the carotid plexus ; C,
cervical plexus ; Br, brachial plexus ; D 6, sixth intercostal nerve ; D 12, twelfth ; L3,
third lumbar nerve; § 1, first sacral nerve ; 8 3, third ; S 5, fifth ; Cr, anterior crural
nerve ; Cr’, great sciatic; pn, pneumo-gastric nerve in the lower part of the neck ; 7,
recurrent nerve winding round the subclavian artery.

Sympathetic Cord—c, superior cervical ganglion ; c’, second or middle ; ce", inferior ;
from each of these ganglia cardiac nerves (all deep on this side) are seen descending to
the cardiac plexus ; d 1, placed immediately below the first dorsal sympathetic ganglion ;
d 6, is opposite the sixth ; 71, first lumbar ganglion; cg, the terminal or coccygeal
ganglion.

Preaortic and Visceral Plexuses.—p p, pharyngeal, and, lower down, laryngeal
plexus ; pl, posterior pulmonary plexus spreading from the pneumo-gastric on the back
of the right bronchus ; ¢ a, on the aorta, the cardiac plexus, towards which, in addition
to the cardiac nerves from the three cervical sympathetic ganglia, other branches are seen
descending from the pneumo-gastric and recurrent nerves ; ¢ 0, right or posterior, and co’,
left or anterior coronary plexus ; 0, cesophageal plexus in long meshes on the gullet ; sp,
great splanchnic nerve formed by branches from the fifth, sixth, seventh, eighth, and
ninth dorsal ganglia ; +, small splanchnic from the ninth and tenth ; + +, smallest or
third splanchnic from the eleventh : the first and second of these are shown joining the
solar plexus, so; the third descending to the renal plexus, 7 e; connecting branches
between the solar plexus and the pneumo-gastric nerves are also represented ; p 7’, above
the place where the right pneumo-gastric passes to the lower or posterior surface of the
stomach ; pw’, the left distributed on the anterior or upper surface of the cardiac portion
of the organ: from the solar plexus large branches are seen surrounding the arteries of
the cceliac axis, and descending to ms, the superior mesenteric plexus ; opposite to this
is an indication of the suprarenal plexus; below xe (the renal plexus), the spermatic
plexus is also indicated ; a 0, on the front of the aorta, marks the aortic plexus, formed
by nerves descending from the solar and superior mesenteric plexuses and from the lumbar
ganglia ; m7, the inferior mesenteric plexus surrounding the corresponding artery ; h ¥,
hypogastric plexus placed between the common iliac vessels, connected above with the
aortic plexus, receiving nerves from the lower lumbar ganglia, and dividing below into the
right and left pelvic or inferior hypogastric plexuses ; p /, the right pelvic plexus ; from
this the nerves descending are joined by those from the plexus on the superior hemor-
rhoidal vessels, mz’, by sympathetic nerves from the sacral ganglia, and by numerous
visceral nerves from the third and fourth saeral spinal nerves, and there are thus formed
the rectal, vesical, and other plexuses, which ramify upon the viscera from behind for-
wards, and from below upwards, as towardsz 7, and v, the rectum and blacder.

and ligaments. Several of these branches enter the posterior pulmonary
lexus.

; The branches furnished by the lower six or seven ganglia unite into

three cords on each side, which pass down to join plexuses in the

abdomen, and are distinguished as the great, the small, and the smallest

splanchnic nerve.

The Great Splanchnic Nerve.—This nerve is formed by the union
of small cords (roots) given off by the thoracic ganglia from the fifth or
sixth to the ninth or tenth inclusive. By careful examination of speci-
mens after immersion in acetic or diluted nitric acid, small filaments
may be traced from the splanchnic roots upwards as far as the third
ganglion, or even as far as the first (Beck, in the “ Philosophical Trans-
actions,” Part 2, for 1846).

Gradually augmented by the successive addition of the several roots,
the cord descends obliquely inwards over the bodies of the dorsal
vertebrae ; and, after perforating the crus of the diaphragm at a variable

636 THE SYMPATHETIC NERVES AND GANGLIA.

point, terminates in the semilunar ganglion, frequently sending some
filaments to the renal plexus and the suprarenal body.

The splanchnic nerve is remarkable from its white colour and
firmness, which are owing to the preponderance of the spinal nerve-
fibres in its composition.

Varieties.—In the chest the great splanchnic nerve is not unfrequently divided
into parts, and forms a plexus with the small splanchnic nerve. Occasionally
also a small ganglion (ganglion splanchnicum) is formed on it over the last dorsal
vertebra, or the last but one; and when it presents a plexiform arrangement,
several small ganglia have been observed on its divisions.

In eight instances out of a large number of bodies, Wrisberg observed a fourth
splanchnic nerve (nervus splanchnicus supremus). It is described as formed by
offsets from the cardiac nerves, and from the lower cervical as well as some of
the upper thoracic ganglia, (‘“Obsery. Anatom. de Nerv. Viscerum particula
prima,” p. 25, sect. 3.)

Small Splanchnic Nerve.—The small or second splanchnic nerve
springs from the tenth and eleventh ganglia, or from the neighbouring
part of the cord. It passes along with the preceding nerve, or separately
through the diaphragm, and ends in the ceeliac plexus. In the chest
this nerve often communicates with the large splanchnic nerve ; and in
some instances it furnishes filaments to the renal plexus, especially if
the lowest splanchnic nerve is very small or wanting.

Smallest Splanchnic Nerve.—This nerve (nerv. renalis posterior—
Walter) arises from the twelfth thoracic ganglion, and communicates
sometimes with the nerve last described. After piercing the diaphragm,
it ends in the renal plexus, and in the inferior part of the cceliac plexus.

LUMBAR PART OF THE GANGLIATED CORD.

In the lumbar region the two gangliated cords approach one another
more nearly than in the thorax. They are placed before the bodies of
the vertebrae, each lying along the inner margin of the psoas muscle ;
and that of the right side is partly covered by the vena cava.

The ganglia are small, and of an oval shape. They are commonly
four in number, but occasionally, when their number is diminished,
they are of larger size.

Connection with spinal nerves—lIn consequence of the greater distance
at which the lumbar ganglia, are placed from the intervertebral foramina
the branches of connection with the spinal nerves are longer than in
other parts of the gangliated cord. There are generally two connecting
branches for each ganglion, but the number is not so uniform as it is
in the chest ; nor are those belonging to any one ganglion connected
always with the same spinal nerve. The connecting branches accom-
pany the lumbar arteries, and, as they cross the bodies of the vertebra,
are covered by the fibrous bands which give origin to the larger psoas
muscle.

Brancues.—The branches of these ganglia are uncertain in their
number. Some join a plexus on the aorta; others descending go to

form the hypogastric plexus. Several filaments are distributed to the
vertebree and the ligaments connecting them.

SACRAL PART OF THE GANGLIATED CORD.

Over the sacrum the gangliated cord of the sympathetic nerve is
much diminished in size, and gives but few branches to the viscera.

LUMBAR AND SACRAL NERVES AND GANGLIA. 637

Its position on the front of the sacrum is along the inner side of the
anterior sacral foramina; and like the two series of those foramina, the
two cords approach one another in their progress downwards. The
upper end of each is connected with the last lumbar ganglion by a
single or a double interganglionic cord ; and at the lower end they are
connected by means of a loop with a single median ganglion, ganglion
impar, placed on the fore part of the coccyx. The sacral ganglia are
usually five in number ; but the variation both in size and number is
more marked in these than in the thoracic or lumbar ganglia.

Connection with spinal nerves—From the proximity of the sacral
ganglia to the spinal nerves at their emergence from the foramina, the
communicating branches are very short : there are usually two for each
ganglion, and these are in some cases connected with different sacral
nerves. The coccygeal nerve communicates with the last sacral, or the
coccygeal ganglion.

BRANCHES.—The branches proceeding from the sacral ganglia are
much smaller than those from other ganglia of the cord. They are
for the most part expended on the front of the sacrum, and join the
corresponding branches from the opposite side. Some filaments from
one or two of the first ganglia enter the hypogastric plexus, while
others go to form a plexus on the middle sacral artery. From the loop
connecting the two cords on which the coccygeal ganglion is formed,
filaments are given to the coccyx and the ligaments about it, and to
the coccygeal gland.

Coccygeal Gland.

Under this name has been described by Luschka a minute structure,
which has since received the attention of a number of writers. It is
usually, according to Luschka, of the size of a lentil, and sometimes
as large as a small pea; its colour is reddish grey ; its surface lobu-
lated ; and it occupies a hollow at the tip of the coccyx, between the
tendons attached to that part. It receives terminal twigs of the middle
sacral artery and minute filaments from the ganglion impar. It con-
sists of an aggregation of grains or lobules, which in some instances
remain separate one from another. These lobules are principally
composed of thick-walled cavities of vesicular and tubular appearance,
described by Luschka and subsequent writers as closed follicles filled
with cellular contents, but recently demonstrated by Julius Arnold to be
clumps of dilated and tortuous small arteries, with thickened muscular
and epithelial coats. Nerve-cells are found scattered in the stroma of
the organ.

The coccygeal gland is a structure evidently of a similar nature to the ganglion
intercaroticum, the principal differences apparently being, that the glomeruli
of the ganglion intercaroticum are produced principally by the convolution and

* ramification of arterial twigs, while in the coccygeal gland there is dilation of
the branches and thickening of their walls; and that the nervous element is
more developed in the intercarotid ganglion than in the coccygeal gland. Arnold,
with Luschka, appears inclined to consider both structures as allied in nature to
the suprarenal capsules. According to Arnold, there is always a number of small
grape-like appendages on the coccygeal part of the middle sacral artery, micro-
scopic in size, but similar in nature to the lobules of which the coccygeal gland
is composed. (Luschka, ‘“‘ Der Hirnanhang und die Steissdriise des Menschen.”
Berlin, 1860. Also “ Anat. d. Mensch.,” vol. ii, part 2, p. 187. Julius Arnold in
Virchow’s ‘“ Archiv,” March, 1865.)

638 THE SYMPATHETIC NERVES AND GANGLIA,

THE GREAT PLEXUSES OF THE SYMPATHETIC.

Under this head may be included certain large plexuses of nerves
placed further forwards in the visceral cavity than the gangliated cords,
and furnishing branches to the viscera. The principal of these plexuses
are the cardiac, the solar, and the hypogastric with the pelvic plexuses
prolonged from it. They are composed of assemblages of nerves, or of
nerves and ganglia, and from them smaller plexuses are derived.

CARDIAC PLEXUS.

This plexus receives the cardiac branches of the cervical ganglia and
those of the pneumo-gastric nerves, and from it proceed the nerves
which supply the heart, besides some offsets which contribute to the
nervous supply of the lungs. It lies upon the aorta and pulmonary
artery, where these vessels are in contact, and in its network are dis-
tinguished two parts, the superficial and the deep cardiac plexuses, the
deep plexus being seen behind the vessels, and the superficial more in
front, but both being closely connected. The branches pass from these
plexuses chiefly forward in two bundles, accompanying the coronary
arteries.

Superficial Cardiac Plexus.—The superficial cardiac plexus lies in
the concavity of the arch of the aorta, in front of the right branch of
the pulmonary artery. In it the superficial or first cardiac nerve of
the sympathetic of the left side terminates, either wholly or in part,
together with the lower cardiac branch of the left pneumo-gastric nerve,
and in some cases also that of the right side. In the superficial plexus
a small ganglion, the ganglion of Wrisberg, is frequently found at the
point of union of the nerves. Besides ending in the anterior coronary
plexus, the superficial cardiac plexus furnishes laterally filaments along
the pulmonary artery to the anterior pulmonary plexus of the left side.

Deep Cardiac Plexus.—The deep cardiac plexus, much larger than
the superficial one, is placed behind the arch of the aorta, between it
and the end of the trachea, and above the point of division of the pul-
monary artery.

This plexus receives all the cardiac branches of the cervical ganglia
of the sympathetic nerve, except the first or superficial cardiac nerve of
the left side. It likewise receives the cardiac nerves furnished by the
vagus and by the recurrent laryngeal branch of that nerve, with the
exception of the left lower cardiac nerve.

Of the branches from the right side of the plexus, the greater number
descend in front of the right pulmonary artery, and join branches from
the superficial part in the formation of the anterior coronary plexus,
while the rest, passing behind the right pulmonary artery, are distri-
buted to the right auricle of the heart, and a few filaments are continued
into the posterior coronary plexus.

On the left side, a few branches pass forwards by the side of the
ductus arteriosus to join the superficial cardiac plexus ; but the great
majority end in the posterior coronary plexus.

The deep cardiac plexus sends filaments to the anterior pulmonary
plexus on each side.

Coronary Plexuses.—The anterior coronary plexus, formed at first from the
fibres of the superficial cardiac plexus, passes forwards between the aorta and

SOLAR OR EPIGASTRIC PLEXUS. 639

pulmonary artery, and having received an accession of fibres from the deep
cardiac plexus follows the course of the left or anterior coronary artery.

The posterior coronary plexus, derived chiefly from the left part of the deep
cardiac plexus, but joined by nerves from the right portion of that plexus sur-
rounding the branches of the right coronary artery accompanies them to the
back of the heart.

Nervous filaments ramify in great number under the lining membrane of the
heart. They are not so easily distinguished in man as in some animals. In the
heart of the calf or the lamb they are distinctly seen without dissection, running
in lines which cross obliquely the muscular fibres. - Remak was the first to observe
that these branches are furnished with small ganglia, both on the surface and
in the muscular substance. (Miiller’s “ Archiv,” 1844.) For a description of the
Ganglia and Nerves of the Heart from original observations, see I. Bell Pettigrew,
“Physiol, of the Circulation,” &c., 1874, p. 293.

SOLAR OR EPIGASTRIC PLEXUS,

The solar or epigastric plexus, which is the largest of the prevertebral
centres, is placed at the upper part of the abdomen, behind the stomach,
and in front of the aorta and the pillars of the diaphragm. Surrounding
the origin of the cceliac axis and the upper mesenteric artery, it occu-
pies the interval between the suprarenal bodies, and extends downwards
as far as the pancreas. The plexus consists of nervous cords, with
several ganglia of various sizes connected with them. The large
splanchnic nerves on both sides, and some branches of the pneumo-
gastric, terminate in it. The branches given off from it are very
numerous, and accompany the arteries to the principal viscera of the
abdomen, constituting so many secondary plexuses on the vessels.
The diaphragmatic, cceliac, mesenteric, and other plexuses are recog-
nised, which follow the corresponding arteries.

Semilunar ganglia.—The solar plexus contains, as already men-
tioned, several ganglia ; and by the presence of these bodies, and their
size, it is distinguished from the other prevertebral plexuses. The
two principal ganglionic masses, named semlunar, though they have
often little of the form the name implies, occupy the upper and outer
part of the plexus, one on each side, and are placed close to the supra-
renal bodies by the side of the cceliac and the superior mesenteric
arteries. At the upper end, which is expanded, each ganglion receives
the great splanchnic nerve.

Diaphragmatic Plexus.—The nerves (inferior diaphragmatic) composing this
plexus are derived from the upper part of the semilunar ganglion, and are larger
on the right than on the left side. Accompanying the arteries along the lower
surface of the diaphragm, the nerves sink into the substance of the muscle.
They furnish some filaments to the suprarenal body, and join with the spinal
phrenic nerves.

At the right side, on the under surface of the diaphragm, and near the supra-
renal body, there is a small ganglion, (ganglion diaphragmaticum,) which marks
the junction between the phrenic nerves of the spinal and sympathetic systems.
From this small ganglion filaments are distributed to the vena cava, the supra-
renal body, and the hepatic plexus. On the left side the ganglion is wanting,
but some filaments are prolonged to the hepatic plexus.

Suprarenal Plexus.—The suprarenal nerves issue from the solar plexus and
the outer part of the semilunar ganglion, a few filaments being added from
the diaphragmatic nerve, They are short, but numerous in comparison with the
size of the body which they supply: they enter the upper and inner parts of
the suprarenal capsule. These nerves are continuous below with the renal
plexus, The plexus is joined by branches from one of the splanchnic nerves,
and presents a ganglion (gangl, splanchnico-suprarenale), where it is connected

640 THE SYMPATHETIC NERVES AND GANGLIA.

with those branches. The plexus and ganglion are smaller on the left than on
on the right side.

Renal Plexus.—The nerves forming the renal plexus, fifteen or twenty in
number, emanate for the most part from the outer part of the semilunar gan-
glion; but some are added from the solar and aortic plexuses. More-
over, filaments from the smallest splanchnic nerve, and occasionally from the
other splanchnic nerves, terminate in the renal plexus. In their course along
the renal artery, ganglia of different sizes are formed on these nerves. Lastly,
dividing with the branching of the vessel, the nerves follow the renal arteries
into the substance of the kidney. On the right side some filaments are fur-
nished to the vena cava, behind which the plexus passes with the renal artery ;
and others go to form the spermatic plexus,

Spermatic Plexus.—This small plexus commences in the renal, but receives
in its course along the spermatic artery an accession from the aortic plexus.
Continuing downwards to the testis, the spermatic nerves are connected with
others which accompany the vas deferens and its artery from the pelvis.

In the female, the plexus, like the artery, is distributed to the ovary and the
uterus.

Ceeliac Plexus.—This plexus is of large size, and is derived from the fore part
of the great epigastric plexus. It surrounds the coeliac axis in a kind of mem-
branous sheath, and subdivides, with the artery, into coronary, hepatic, and
splenic plexuses, the branches of which form communications corresponding”
with the arches of the arterial anastomosis. The plexus receives offsets from one
or more of the splanchnic nerves, and on the left side a branch from the pneumo-
gastric nerve is continued into it. (Swan.)

The coronary plexus is placed with its artery along the small curvature of the
stomach, and unites with the nerves which accompany the pyloric artery, as
well as with branches of the pneumo-gastric nerves. The nerves of this plexus
enter the coats of the stomach, after running a short distance beneath the
peritoneum.

The hepatic plexus, the largest of the three [divisions of the cceliac plexus,
ascends with the hepatic vessels and the bile-duct, and, entering the substance
of the liver, ramifies on the branches of the vena ports and the hepatic artery.
Offsets from the left pneumo-gastric and diaphragmatic nerves join the hepatic
plexus at the left side of the vessels. From this plexus filaments are furnished
to the right suprarenal plexus, as well as other secondary plexuses which
follow the branches of the hepatic artery. Thus there is a cystic plexus to the
gall-bladder ; and there are pyloric, gastro-epiploic, and gastro-duodenal plexuses,
which unite with coronary, splenic, and mesenteric nerves.

The splenic plexus, continued on the splenic artery and its branches into the
substance of the spleen, is reinforced at its beginning by branches from the left
semilunar ganglion, and by a filament from the right vagus nerve. It furnishes
the left gastro-epiploic and pancreatic plexuses, which course along the corre-
sponding branches of the splenic artery, and, like the vessels, are distributed to
the stomach and pancreas.

Superior Mesenteric Plexus.—The plexus accompanying the superior me-
senteric artery, whiter in colour and firmer than either of the preceding offsets
of the solar plexus envelopes the artery in a membraniform sheath, and receives
a prolongation from the junction of the right pneumo-gastric nerve with the
ceeliac plexus. Near the root of the artery, ganglionic masses (gangl. meseraica)
occur in connection with the nerves of this plexus.

The offsets of the plexus are in name and distribution the same as the vessels.
In their progress to the intestine some of the nerves quit the arteries which first
supported them, and are directed forwards in the intervals between the vessels.
As they proceed they divide, and unite with lateral branches, like the arteries, but
without the same regularity : they finally pass upon the intestine along the line
of attachment of the mesentery.

The Aortic Plexus.—The aortic or intermesenteric plexus, placed along the
abdominal aorta, and occupying the interval between the origin of the superior
and inferior mesenteric arteries, consists, for the most, of two lateral portions,

THE CdiLIAC, AORTIC, AND MESENTERIC PLEXUSES. 641

connected with the semilunar ganglia and renal plexuses, which are extended on
the sides of the aorta, and which meet in several larger communicating branches
over the middle of that vessel. It is joined by branches from some of the lumbar
ganglia, and presents not unfrequently one or more distinct ganglionic enlarge-
ments towards its centre.

The aortic plexus furnishes the inferior mesenteric plexus and part of the
spermatic, gives some filaments to the lower vena cava, and ends below in the
hypogastric plexus.

Inferior Mesenteric Plexus.—This plexus is derived principally from the left
lateral part of the aortic plexus, and closely surrounds with a network the
inferior mesenteric artery. It distributes nerves to the left or descending part
and the sigmoid flexure of the colon, and assists in supplying the rectum. The
nerves of this plexus, like those of the superior mesenteric plexus, are firm in
texture and of a whitish colour,

The highest branches (those on the left colic artery) are connected with the
last branches (middle colic) of the superior mesenteric plexus, while others in
the pelvis unite with offsets derived from the pelvic plexus.

HYPOGASTRIC PLEXUS.

The hypogastric plexus, the assemblage of nerves destined for the
supply of the viscera of the pelvis, lies invested in a sheath of dense
connective tissue, in the interval between the two common iliac arteries.
It is formed by eight or ten nerves on each side, which descend from the
aortic plexus, receiving considerable branches from the lumbar ganglia,
and, after crossing the common iliac artery, interlace in the form of a flat
plexiform mass placed in front of the lowest lumbar vertebra. The
plexus contains no distinct ganglia. At the lower end it divides into
two parts, which are directed forwards, one to each side of the pelvic
viscera, and form the pelvic plextises.

PELVIC PLEXUS.

The pelvic or inferior hypogastric plexuses, one on each side, are
placed in the lower part of the pelvic cavity by the side of the rectum,
and of the vagina in the female. The nerves, prolonged from the
hypogastric plexus, enter into repeated communications as they descend,
and form at the points of connection small knots, which contain a
little ganglionic matter. After descending some way, they become
united with branches of the spinal nerves, as well as with a few offsets
of the sacral ganglia, and the union of all constitutes the pelvic plexus.
The spinal branches, which enter into the plexus, are furnished from
the third and fourth sacral nerves, especially the third; and filaments
are likewise added from the first and second sacral nerves. Small
ganglia are formed at the places of union of the spinal nerves, as well
as elsewhere in the plexus (plexus gangliosus—Tiedemann).

From the plexus so constituted, numerous nerves are distributed to
the pelvic viscera. They correspond with the branches of the internal
iliac artery, and vary with the sex; thus, besides hemorrhoidal and
vesical nerves, which are common to both sexes, there are nerves special
to each :—namely, in the male for the prostate, vesicula seminalis, and
vas deferens ; in the female, for the vagina, uterus, ovary, and Fallo-
pian tube.

The nerves distributed to the urinary bladder and the vagina contain
2 larger proportion of spinal nerves than those furnished to the other
pelvic viscera. {

vou. I, HN Gy

642 THE SYMPATHETIC NERVES AND GANGLIA.

Inferior Hzemorrhoidal Nerves.—These slender nerves proceed
from the back part of the pelvic plexus. They join with the nerves
(superior hemorrhoidal) which descend with the inferior mesenteric
artery, and penetrate the coats of the rectum.

Vesical Plexus.—The nerves of the urinary bladder are very nu-
merous. ‘They are directed from the anterior part of the pelvic plexus
to the side and lower part of the bladder. At first these nerves
accompany the vesical blood vessels, but afterwards they leave the
vessels, and subdivide into minute branches before perforating the
muscular coat of the organ. Secondary plexuses are given in the male
to the vas deferens and the vesicula seminalis.

The nerves of the vas deferens ramify round that tube, and communi-
cate in the spermatic cord with the nerves of the spermatic plexus.
Those furnished to the vesieula seminalis form an interlacement on the
vesicula, and some branches penetrate its substance. Other filaments
from the prostatic nerves reach the same structure.

Prostatic Plexus.—The nerves of this plexus are of considerable
size, and pass onwards between the prostate gland and the levator ani.
Some are furnished to the prostate and to the vesicula seminalis ; and
the plexus is then continued forwards to supply the erectile substance of
the penis, where its nerves are named “ cavernous.”

Cavernous nerves of the penis.—These are very slender, and difficult
to dissect. Continuing from the prostatic plexus they pass onwards,
beneath the arch of the pubes, and through the muscular structure
connected with the membranous part of the urethra, to the dorsum of
the penis. At the anterior margin of the levator ani muscle the
cavernous nerves are joined by some short filaments from the pudic
nerve. After distributing twigs to the fore part of the prostate, these
nerves divide into branches for the erectile substance of the penis, as
follows :—

Small cavernous nerves (Miller), which perforate the fibrous covering
of the corpus cavernosum near the root of the penis, and end in the
erectile substance.

The large cavernous nerve, which extends forward on the dorsum of
the penis, and dividing, gives filaments that penetrate the corpus
cavernosum, and pass with or near the cavernous artery (art. profunda
penis). As it continues onwards, this nerve joins with the dorsal branch
of the pudic nerve about the middle of the penis, and is distributed to
the corpus cayernosum. Branches from the foregoing nerves reach the
corpus spongiosum urethre. (Miiller, “ Ueber die organischen Nerven
der erectilen miinnlichen Geschlechtsorgane,” &c. Berlin, 1836.)

Nerves of the Ovary.—-The ovary is supplied chiefly from the
plexus prolonged on the ovarian artery from the abdomen; but it
receives another offset from the uterine nerves.

Vaginal Plexus.—The nerves furnished to the vagina leave the
lower part of the pelvic plexus—that part with which the spinal nerves
are more particularly combined. They are distributed to the vagina
without previously entering into a plexiform arrangement; and they
end in the erectile tissue on the lower and anterior part, and in the
mucous membrane.

Nerves of the Uterus.—These nerves are given more immediately
from the lateral fasciculus prolonged to the pelvic plexus from the
hypogastric plexus, above the point of connection with the sacral nerves.

THE PELVIC NERVES AND PLEXUS. 643

Separating opposite the neck of the uterus, they are directed upwards
with the blood-vessels along the side of this organ, between the layers
of its broad ligament. Some very slender filaments form round the
arteries a plexus, in which minute ganglia are found scattered at in-
tervals, and these nerves continue their course in the substance of the
organ in connection with the blood-vessels. But the larger part of the
nerves soon leave the vessels ; and after dividing repeatedly, without
communicating with each other and without forming any gangliform
enlargements, sink into the substance of the uterus, penetrating for the
most part its neck and the lower part of its body. One branch, con-
tinued directly from the common hypogastric plexus, reaches the body
of the uterus above the rest ; and a nerve from the same source ascends
to the Fallopian tube. Lastly, the fundus of the uterus often receives
a branch from the ovarian nerve. (Fr. Tiedemann, Tab. Nerv. Uteri,
Heidelberg, 1823 ; Robert Lee, in Phil. Trans, 1841, 1842, 1846, and
1849 ; and Snow Beck, in Phil. Trans., 1846, part ii. See also F.
Frankenhiiuser, Die Nerven der Gebiirmutter, 1867.)

The nerves of the gravil uterus have been frequently investigated,
with a view to discover if they become enlarged along with the increase
in size of the organ. It is ascertained that the increase which takes
place is confined, for the most part to the thickening of the fibrous
envelopes of the nerves ; but it appears also, from the researches of
Kilian, that fibres furnished with a medullary sheath, which in the un-
impregnated state of the uterus lose that sheath as they proceed to their
distribution, in the impregnated condition of the uterus continue to
be surrounded with it as they run between the muscular fibres. (Farre,
in Supplement of Cyclopedia of Anat. and Phys., “ Uterus and Ap-
pendages.’’)

TZ

INDEX O° VOLUME TF

——+—

ABDOMEN (abdo, I hide), fascia of, lining,
324
superficial, 314
lymphaties of, 508
muscles of, 314
nerves of, 625
Abdominal aorta, 422
artery (internal mammary), 391
(lumbar), 436
nerve (hypogastric), 600
ring, external or superficial, 316
internal or deep, 324
Abducent (ab, from; duco, I lead), nerves,
519, 547
Abduction, 132
Abductor. See Muscres.
Aberrant arteries, 403, 404
Accessorius ad ilio-costalem, 300
Accessory artery, pudic, 447
nerve, obturator, 604
spinal, 564
process of lumbar verteb re, 14, 25
Acetabulum (a vessel for holding vinegar),
100, 103
Acromial artery, 395
Acromio-clayicular articulation, 147
Acromion (&«poy, a summit ; amos, top
of the shoulder), 83
ossification of, 96
Acromio-thoracic artery; 395
vein, 489
Adduction (ad, to; duco, I lead), 132
Adductor. See Muscuss.
Age, difference inform of skull, 77
Air-sinuses in bones of head, 66
Ale of diaphragm, 311
of sphenoid bone, 43
of vomer, 51
Alar ligaments of knee, 170
odontoid, 139
thoracic artery, 395
vein, 489
Alisphenoid bones, 74
Alveolar artery, 371
Alvyeoli (alveolus, a small hollow vessel),
of lower jaw, 54
upper jaw, 47
Amphiarthrosis (oui, on both sides,
intermediate ; ap@poy, a joint), 132

Anal fascia, 326
muscles, 327, 331
nerves, 626

Analogy of organs, 5

Anapophysis (avd, upon; apophysis),
14, 25
Anastomoses (avd, through; ordua, a

mouth), of branches of abdominal
aorta, 436
Anastomotic artery, of arm, 402
pubic, 443
of thigh, 460
Anatomy (avd, apart ; Téuvw, I cut),
embryological, 2
general and descriptive, I
morphological and physiological, 2
object of, 1
systematic and topographical, 2
Anconeus (aykév, the elbow), 207
Angeiology (ayyeiov, a vessel ; Adyos, dis-
course), 343
Angle, ethmo-cranial, 80
facial, 79
occipital, So
premaxillary, 80
saddle, So
Angular artery, 365
movement, 132
processes of frontal bone, 36
vein, 476
Ankle-joint, ligaments of, 173
annular, 244.
movements of, 174
muscles passing over, 263
Annular (annulus, a ring) ligament o
ankle, 244
radio-ulnar
150
of wrist, 157, 208, 209
Ansa (a loop) hypoglossi, 567, 578
Ansz Vieussenli, 633
Antibrachium (ay7/, opposite; brachium\
81
Antrum (a cavern), 9
of Highmore, 49
Aorra (perhaps from defpw, I take up
or carry), 346
abdominal, 422
branches of, parietal, 435

of articulation,

646 INDEX TO VOLUME I.

AorTA—continucd.
abdominal, branches of, visceral,
424
anastomoses of visceral and pa-
’ rietal branches of, 436
varieties of, 424
arch of, 346
branches of, 348, 353
varieties of, 351
foramen in diaphragm for, 311
thoracic, descending, 419
branches of, 420
varieties of, 350
Aortic plexus, 640
Aponeurosis (a7é, from ; vetpoy, a string,
a tendon), 186
of arm, 204
of diaphragm, 311
epicranial, 264
ot external oblique muscle, 316
fore-arm, 208
internal oblique muscle, 317
leg, 243
lumbar, 187, 299, 325
occipito-frontal, 264
of transversalis muscle, 320
vertebral, 299
Apophysis (ard, from ; ¢vw, I grow), §
Apparatus ligamentosus colli, 140
Appendicular portions of body, 3, 122
Aqueduct (aqueductus, a conduit) of
Fallopius, 40
Aqueeductus cochlez, 41
vestibuli, 41
Arch of aorta, 346. See AonTA.
carpal, posterior, 409
crural or femoral, 341
deep, 324, 341
malar, 60
orbital, 35
palmar, superficial, 411
deep, 419
plantar, 466
scapulo-clavicular, ligaments of, 146
subpubiec, 104
of a vertebra, 10
zygomatic, 60
Arches, axillary, 191
lateral, of skull, 76
neural, of head, 74, 76
of vertebrie, 2
visceral, of head, 74, 76
Arcus dorsalis humeri posticus, 402
Arm, aponeurosis of, 204
arteries of, 399
bones of, 81
fascize of, 204
lymphaties of, 515
muscles of, 204
nerves of, cutaneous, 623
muscular, 208, 625
veins of, 485
Arnold, ganglion of, 546
ARTERIA comes nervi ischiadici, 448
comes nervi phrenici, 391

ARTERIA—continuen.
dorsalis pedis, 469
dorsalis scapule, 397
hypogastrica, 439
pancreatica magna, 428
princeps pollicis, 417
profunda femoris, 457
profunda penis, 447
thoracica humeraria, 395
suprema, 395
thyroidea ima, 355
ARTERIES (aprnpia, from aprip, that by
which anything is suspended ; ori-
ginally applied to the windpipe,
by which the lungs might be said
to be suspended, tpaxe?a aprypla,
arteria aspera, afterwards to the
arteries, at one time supposed,
like the windpipe, to contain air.
Another less probable derivation
is from amp, air; typéw, I keep),
Descriptive Anatomy of, 343
ARTERIES or ARTERY, abdominal, of in-
ternal mammary, 391
of lumbar arteries, 436
aberrant, in arm, 403, 404
accessory pudic, 447
acromial, 395
acromio-thoracic, 395
alar thoracic, 395
alveolar, 371
anastomotic, of arm, 402
pubie, 443
of thigh, 460
angular, of face, 365
articular, of hip, 458
of knee, 462
of auditory nerve, 386
auricular, anterior, 369
posterior, 367
auricular (occipital); 366
axillary, 394
surgical anatomy of, 399
varieties of, 398
azygos articular, 463
basilar, 383, 385
brachial, 399
surgical anatomy of, 405
varieties of, 402
brachio-cephalic, 355
varieties of, 353, 355
bronchial, 420
buccal, 371
of bulb, 447
capsular, 432
carotid, common, 356
surgical anatomy of, 360
varieties of, 358
external, 360
varieties of, 361
internal, 374
carpal, anterior radial, 416
ulnar, 410
posterior radial, 416
ulnar, 4.09

INDEX TO VOLUME I. 617

ArtTrEny—continued.

central, of retina, 375
cerebellar, anterior inferior, 386
posterior inferior, 385
superior, 386
cerebral, 377
anterior, 378, 379
distribution of, 375
middle, 378, 379
posterior, 379, 38
cervical, ascending, 387
deep, 392
of occipital, 366
superficial, 389
transverse, 389
choroid, 378
posterior, 386
ciliary, 375
circumflex, of arm, anterior, 398
posterior, 398
iliac, deep, 452
superticial, 456
of thigh, external, 458
internal, 458
clavicular, 395
of clitoris, 448
cocceygeal, 448
eceliac, 424
colic, left, 430
middle, 430
right, 430
communicating, of brain, anterior,

378 4
posterior, 386
of palm, 411
coronary of heart, 353
of lips, 365
of stomach, 425
of corpus cavernosum, 447
cranial, 366
cremasteric, 452
crico-thyroid, 363
cystic, 427
dental, inferior, 371
superior, 371
digital, of foot, 467, 471
of hand, 412
dorsal, of foot, 469
of fore-finger, 417
of great toe, 471
of lumbar, 436
of penis, 447
of scapula, 397
of thumb, 417
of tongue, 364
emulgent, 432
epigastric, deep or inferior, 451
relation to femoral hernia, 341
to inguinal hernia, 336
superficial, 456
superior, 391
varieties of, 453
ethmoidal, 375
facial, 364
femoral, 453

ARTERY — continued.

femoral, relation to hernia, 341
surgical anatomy of, 461
varieties of, 460
deep, 457

frontal, 377

gastric, short, 425

gastro-duodenal, 425

gastro-epiploic, left, 428
right, 425

gluteal, 448

hemorrhoidal, inferior or external,

445
middle, 441
superior, 430, 432
of hand, varieties of, 419
hepatic, 425
humeral, 399
of acromio-thoracic, 395
transverse, 387
hyoid (lingual), 363
(thyroid), 363
hypogastric, 440
ileo-colic, 430
iliac, common, 437
surgical anatomy of, 439
varieties of, 439
external, 450
surgical anatomy of, 453
varieties of, 453
internal, 439
in foetus, 440
surgical anatomy of, 453
ilio-lumbar, 448
of index-finger, radial, 417
infra-orbital, 371
infraspinous, 389
innominate, 355
varieties of, 353, 355
intercostal, aortic, 420
anterior of internal mammary,
391
superior, 392
interosseous, of arm, 408
anterior, 409
posterior, 409
of foot, 470
of hand, dorsal, 409, 417
palmar, 419
intestinal, 428
labial, inferior, 365
lachrymal, 375
laryngeal, of inferior thyroid, 387
of superior thyroid, 363
lingual, 363
lumbar, 436
malar, 375
malleolar, 469
mammary, external, 395
internal, 390
masseteric, 371
mastoid, 366
maxillary, internal, 369
varieties of, 373
superior, 371

INDEX TO VOLUME I.

ARTERY—continued.

median, 409
varieties of, 411
anterior, 385
mediastinal, 391
posterior, 420
meningeal, of ascending pharyngeal,
374
middle or great, 377
of occipital, 366
posterior, 384
small, 371
mesenteric, inferior, 430
superior, 428
metacarpal, 417
of little finger, 409
metatarsal, 470
musculo-phrenic, 391
mylo-hyoid, 371
nasal, of internal maxillary, 373
lateral, 365
of ophthalmic, 377
of septum, 365
nutrient, of femur, 459
of fibula, 465
humerus, 402
lium, 448
radius, 409
tibia, 464
ulna, 409
obturator, 442
relation to femoral hernia, 34%
varieties of, 444
occipital, 366
cesophageal, of aorta, 420
of coronary artery, 425
of inferior thyroid, 387
ophthalmic, 375
ovarian, 433
palatine, inferior or ascending, 364
superior or descending, 372
of pharyngeal, 373
palmar, superficial, 411
deep, 418
palpebral, 377
pancreatic, 428
pancreatico-duodenal, inferior, 428
superior, 427
perforating, of foot, 467, 471
of hand, 419
of thigh, 458
of thorax, 391
pericardiac, 391, 420
perineal, superficial, 445
in female, 447
transverse, 446
peroneal, 464.
anterior, 465
pharyngeal, ascending, 373
phrenic, inferior, 435
superior, 391
plantar, internal, 465
external, 466
popliteal, 461
profunda, of arm, inferior, 402

ARTERY— continued.

profunda, of arm, superior, 402
of penis, 447
of thigh, 457
pterygoid, 371
pterygo-palatine, 373
pubic, of epigastric, 452
of obturator, 443
pudic accessory, 447
external, 456
internal, 444
in female, 447
pulmonary, 345
varieties of, 350, 353
pyloric, 425
radial, 413
varieties of, 417
of index-finger, 417
ranine, 364.
recurrent, of deep palmar arch,
418
interosseous posterior, 409
radial, 415
of superficial palmar arch, 411
tibial, 469
ulnar, anterior, 407
posterior, 408
renal, 432
sacral, middle, 437
lateral, 449
scapular, posterior, 359
sciatic, 445
sigmoid, 432
spermatic, 433
spheno-palatine, 373
spinal, anterior, 385
of intercostals, 422
of inferior thyroid, 387
lateral, 383
of lumbar, 436
posterior, 384
splenic, 428
sternal, 391
sterno-mastoid (occipital), 366
(superior thyroid), 363
stylo-mastoid, 367
subclavian, 379
surgical anatomy of, 392
varieties of, 352, 383
sublingual, 364
submental, 365
subscapular, 395
of suprascapular, 389
supra-acromial, 389
supra-orbital, 375
suprarenal, 432
suprascapular, 387
sural, 462
tarsal, 469
temporal, 367
anterior, 369
deep, 371
middle, 369
posterior, 369
thoracic, acromial, 395

INDEX TO

ARYrERY—continued,
thoracic alar, 395
long, 395
short, 395
of thumb, dorsal, 417
large, 417
thymic, 391
thyroid, inferior, 387
superior, 361
tibial, anterior, 468
varieties of, 471
posterior, 463
varieties of, 465
tonsillar, 365
tracheal, 387
transverse, of basilar, 356
cervical, 389
of face, 367
humeral or scapular, 387
perineal, 446
tympanic, 370
ulnar, 407
varieties of, 410
umbilical, 440
uterine, 441
vaginal, 442
of vas deferens, 440
vertebral, 383
varieties of, 385
vesical, inferior, 440
superior, 440
vesico-prostatic, 440
Vidian, 373
volar, superficial, 416
Arthrodia (&p6poy, a joint), 132
Arthrology (&p@pov, a joint ; Adyos, a dis-
course), 131
Articular (articulus, diminutive of artus,
a joint) nerve. Sce NERVES
artery of hip, 458
of knee, 462
processes of vertebrze, 10
homology of, 24
ARTICULATIONS (articulus, a joint), 131
acromio-clavicular, 147
of ankle, 173
of astragalus, 174
of atlas and axis, 137
ealeaneo-cuboid, 176
of caleaneum, 174
carpal, 155
carpo-metacarpal, 157
classification of, 131
of coccyx, 160
costo-central, 140
costo-sternal, 142
costo-transverse, I4I
cubo-cuneiform, 178
of elbow, 152
foot, 174
fore-arm, 150
hand, 154
hip, 163
interphalangeal of hand, 159
of knee, 166

4

VOLUME I. _ 649

ARTICULATIONS—continued.
of lower limb, 163
metacarpal, 157
metacarpo-phalangeal, 158
metatarsal, 180
metatarso-digital, 181

modes of, 131
movements of, 132
of pelvis, 159
pubic, 163
radio-carpal, 154
radio-ulnar, superior, 150
inferior, 150
of ribs, 140
sacro-coccygeal, 160
sacro-iliac, 161
sacro-vertebral, 159
of sacrum and coecyx, 160
scapho-cuboid, 177
scapho-cuneiform, 178
of seaphoid bone, 175, 177
seapulo-clayicular, 146
of shoulder, 148
sterno-clavicular, 146
tarsal, 174
tarso-metatarsal, 179
temporo-maxillary, 144
tibio-fibular, 172
of trunk and head, 133
of upper limb, 146
vertebral column, 133
Asternal (4, neg. ; o7épvov, the breast)
ribs, 27
Astragalo-calcaneal ligament, 175
Astragalo-seaphoid ligament, 176
Astragalus (aotpdyados, the ankle-bone,
or a die, the astragali of the sheep
having been used as dice by the
ancients), 115
articulation of, 174
homology of, 127, 129
ossification of, 122
Atlanto-axial ligaments, 140
Atlas, 11
ligaments of, 137
ossification of, 21
Attollens (attollo, I raise up) auriculam
muscle, 265
Attrahens (ad, to ; traho, I draw) auri-
culam muscle, 265
Auditory meatus, 40
nerve, 548, 553
process, 40
Auricular arteries, 366, 367, 369
muscles, 265
nerves. See NERVES.
surface of ilium, 102
surface of sacrum, 16, 161
veins, 477
Auriculo-temporal nerve, 543
Axial portion of body, 3
skeleton, relation of limbs to, 123
Axillary arches, 191
artery, 394
fascia, 193

—
ag a a een an avn ans

e50 INDEX TO VOLUME I.

Axillary—continued. _
lymphatic glands, 515
vein, 488

Axis (vertebra), 12

ossification of, 21
ligaments of, 137
celiac, 424
of pelvis, 106
thoracic, 398
thyroid, 386

Azygos (&{vyos, single) artery, 463
pharyngis muscle, 288
uvulz muscle, 289
veins, 489

Back, fascizee and muscles of, 297
lymphatics of, 516
nerves of, cutaneous, 622

muscular, 624

Basal optic ganglion, 528

Basilar (basis, a base) artery, 383, 385
process of occipital bone, 31, 34
sinus, 454.
Basilic vein (BaciAikés, royal ; this vein
having been supposed by the
old physicians to be connected
with the liver and spleen, which
they termed basilic viscera), 487
Basi-hyals, 55, 74
Basi-occipital bone, 34, 76
Basi-sphenoid bone, 76
Bertin, bones of, 42
Biceps (dis, twice ; caput, a head) muscle,
of arm, 205
of leg, 232

Bicipital groove of humerus, 86
tuberosity of radius, 87

Biventer (bis, twice; venter, a belly),
cervicis muscle, 301

Bladder, urinary, ligaments of, true, 326

lyinphaties of, 512
nerves of, 642
Bioop-VEssELs, description of, 343
See ARTERIES and VEINs, also
under the several organs for blood-
vessels belonging to them

Blumenbach’s norma verticalis, 79

Bochdalek’s ganglion, 539

Bones, Descriptive Anatomy of, 7

astragalus, 115, 122

atlas, 11, 21

@xIS; 92.02)

of Bertin, 42

calcanewm, or os calcis, 114, 122

carpal, 90, 100

clavicle, 84, 96

coccyx, 17, 22,

cuboid, 116, 122

cuneiform, of carpus, 91, 100
tarsus, II5, 122

ethmoid, 45, 71

femur, 107, 119

fibula, 112, 119

frontal, 35, 68

of head, 31

| B

ONES — continued.
of head, homologies of, 73
ossification of, 67
humerus, 85, 97
hyoid, 55, 73
ilium, 1ro1, 118
innominate, 100, 118
ischium, 103, 118
lachrymal, 52, 72
of limbs, homological comparison
of, 123
morphology of, 122
of lower limb, 100
ossification of, 119
magnum, 92, 100
malar, 51, 72
maxillary, inferior, 53, 72
maxillary, superior, 47, 71
metacarpal, 93, 100
metatarsal, 116, 122
masal, 52, 72
navicular of tarsus, 115, 122
number of, 9
occipital, 31, 67
palate, 49, 72
parietal, 34, 68
patella, 110, 119
pelvic, 100, 104.
ossification of, 118
phalangeal, of hand, 94, 100
foot, 117, 122
pisiform, 92, 100
pubic, 102, 118
radius, 87, 97
ribs, 27
ossification f, 30
sacrum, 15, 21
scaphoid, of carpus, 91, 100
tarsus, 115, 122
scapula, $1, 95
semilunar, 91, 100
sesamoid, in hand, 95
in foot, 117
sphenoid, 41, 70
spongy, ethmoidal, 46
inferior, 53
middle, 46
sphenoidal, 42, 71
sternum, 2
ossification of, 3
tarsal, 114, 122
temporal, 37, 69
tibia, 110, 119
trapezium, 92, 100
trapezoid, 92, 100
triquetral, 58
turbinated inferior, 53, 72
ulna, 88, 97
of upper limb, 81
ossification of, 95
unciform, 93, 100
vertebra dentata, 12
prominens, II
vertebrae, 9
homology of, 22

sNDEX TO VOLUME I.

Bonns—continued.
vertebra, ossification of, 19
vomer, 51, 72
Wormian, 58
Brachial artery, 399. See ARTERY _
muscles, 204
plexus, 582
vein, 488
Brachialis anticus muscle, 206
Brachio-cephalic (brachium, the arm ;
kepadn, the head) artery, 355
vein, 473
Brachio-radialis muscle, 206
Brachium (arm), 81
Brachycephalic (Bpaxds, short; Kedadn,
the head) skulls, 79
Branchial arches, 74
British skulls, measurements of, 78
Bronchial (Spoyxos, the windpipe) artery,
420
lymphatic glands, 513
veins, 491
Bubonocele (SovBdy, the groin ; KjAn, a
tumour), 337
Buceal (bucca, the mouth) artery, 371
nerves, 543, 551
vein, 476
Buccinator (buccina, a trumpet) muscle,

272
Bulb, olfactory, 526
of urethra, artery of, 447
Bulbo-cayvernosus muscle, 330
Burse, synovial, or burse mucosz,
186
Buttock, nerves of, 623
*

CALCANEO-CUBOID articulation, 176
Calcaneo-fibular ligament, 174
Calcaneo-scaphoid ligaments, 175
Calcaneo-talar (calcaneum; talus,
astragalus) ligament, 174
Calcaneum (belonging to the heel, from
calx, the heel). See Os Calcis

Camper's facial angle, 79
Canal, of bone, 8

carotid, 40

crural or femoral, 227, 341

dental, 54

Eustachian, 40

Hunter's, 455

infra-orbital, 49, 60

inguinal, 335

nasal, 48

neural, 10

palatine, 48, 50, 61

pterygoid, 44

pterygo-palatine, 44, 61

sacral, 17

Vidian, 44, 61
Canals, perivascular, 518
Canine fossa, 48, 58
Caninus muscle, 271
Capitellum (dim. of caput, a head), 8

of humerus, 86
Capitulum (dim. of caput, a head), 8

the

651

Capitulum—continued.
of rib, 27
Capsular artery, 432
ligament of hip, 165
of knee, 169
of shoulder, 148
vein, 194
Caput (a head) of bone, 8

| Caput cornu posterioris, 532

Cardiac («apdia, the heart) ganglia, 639
lymphatic glands, 513
nerves, of pneumogastric, 561
of sympathetic, 631, 632,
633
plexus, 638
veins, 503
Carotid (kapwrides aptnpia, from Kapéw,
I cause sleep: also said to be
from «dpa, the head ; ovs, the ear)
artery, common, 356
external, 360
internal, 374
canal, 40
foramen, 40, 62
nerves, 542, 556
plexuses, 629

| Carpal (kaprés, the wrist) arteries, 4c9,

410, 416
articulations, 155
Carpo-metacarpal articulation, 157
Carpus (kapmés, the wrist), bones of, 90
homology of, 127
ossification of, Too
compared with tarsus, 127
ligaments of, 155, 208, 209
Cartilages of ribs, 29
connections of, 142
See Fibvo-cartilage.
Cauda equina (horse’s tail), 571
Cavernous nerves of penis, 642
plexus, 629, 630
sinus, 483
position of nerves in, 530
Cavities, nasal, 65
Cavity, cotyloid, 9, 103
cranial, 62
glenoid, 9, 83
semilunar of radius, 8S
sigmoid of ulna, 89
Cells, ethmoidal, 45, 67
Central artery of retina, 375
tendon of diaphragin, 311
Centrum of vertebrae, 9, 24
Cephalic (kepady, the head) vein, so
called from having been supposed
by the old physicians to be con-
nected with the head, 486
Cephalo-pharyngeus (kepadn, the head ;
pdpuyé, pharynx) muscle, 288
Cerato-hyals (képas,a horn : hyotd bone),
55, 76
Cerebellum, arteries of, 385, 386
veins of, 481
Cerebral arteries, 377, 386
distribution of, 378

652 INDEX TO VOLUME I.

Cerebral—continued.
veins, 480
Cervical (cerviz, a neck) arteries, 366,
387, 389, 392
fascia, 291
ganglia, 628, 632, 633
lymphatic glands, 516
nerves, 573, 575
plexus, 573, 577
vertebre, 10
Cervicalis ascendens muscle, 300
Cervico-facial division of facial nerve, 551
Cervix (neck) of bone, §
Cheeks, 58
Chest. See Thorax
Chiasma (xiaQw, I mark with the letter
X; crossing or decussation) of
optic tracts, 528
Child, characters ot skeleton in, 130
Chorda dorsalis, 134
tympani, 545, 549
Chord Willisii, 482
Choroid artery, 378
posterior, 386
plexus, 481
Chyliferous (chylus, chyle ; fero, I carry)
vessels, 509
Ciliary (cilium, an eyelash) arteries,
315:
ganglion, 536
nerves, 535, 536
Circle of Willis, 37
Circular muscle of Santorini, 330
sinus, 483
Circulus tonsillaris, 556
Circumduction (circum, about ; dco, I
lead), 132
Circumflex (cirewm, around ; flecto, I
bend) artery, of arm, 398
iliac, 452, 456
of thigh, 458
nerve, 584
vein, iliae, 496, 498
of shoulder, 489
Circumflexus (cirewm, around ; jflecto, I
bend) palati muscle, 290
Clavicle (clavicula, dim. of clavis, a
key), 84
homology of, 123
ligaments of, 146
ossification of, 96
Clavicular artery, 395
Cleido-mastoid (Aeis, a key, or the cla-
vicle ; sastotd process) muscle,
292
Clinoid (KAlvn, a bed ; «los, shape) pro-
cesses, 42
Clitoris (perhaps from kAciw, I enclose),
artery of, 448
Coaptation (con, together ; apto, I fit),
132
Coceygeal (coceyx) artery, 448
gland, 637
nerves, anterior, 606
posterior, 575

Coceygeus (coccyx) muscle, 329
Coccyx (dkkvé, a cuckoo), 9, 17
articulation of, 160
ossification of, 22
Cochleariform (cochleare, a spoon ; forma,
shape) process, 41
Coeliac (koiAia, the abdomen) artery or
axis, 424
plexus, 640
Colic (x@Aoy, the colon or large intestine)
arteries, 430
Collar-bone, 84
Colles, fascia of, 325
Comes (a companion ; pl. comites), nervi
ischiadici, 448
nervi phrenici, 391 :
Commissure (con, together; mitto, I
send) optic, 528
Communicating arteries of brain, 378,
386
of palm, 411
Complexus muscle, 301
Compressor hemispherifim bulbi, 330
naris, 269
Compressores ven dorsalis penis, 330
Condylar foramen, anterior, 33, 62, 65
posterior, 33
surfaces of tibia, 110
Condyle (dvdvaAos, a knuckle), 8
Condyles of femur, 109
of humerus, 86
of lower jaw, 55
of occipital bone, 32, 33, 62
Congenital hernia, 338
Conoid (k@vos, a cone ; 50s, shape) liga-
ment, 147 e
Constrictor muscles of pharynx, 286
isthmi faucium, 289
urethra, 33
Coraco-acromial ligament, 148
Coraco-brachialis muscle, 204
Coraco-clavicular ligament, 147
Coraco-humeral ligament, 149
Coracoid (dépag, a raven; eldos, shape)
ligament, 148
process of scapula, 83 <
Cordiform (cor, the heart ; forma, shape) ©
tendon of diaphragm, 311
Cornicula (corniculwm, dim. of cornu, a
horn) of hyoid bone, 55
Cornua of coceyx, 17
ot fascia lata, 22
of hyoid bone, 55
sacral, 15
sphenoidalia, 42
Coronal suture, 57
Coronary arteries of heart, 353
lips, 365
stomach, 425
plexus of heart, 638
of stomach, 640
sinus, 504
veins of heart, 503
of stomach, 501
Coronoid fossa of humerus, 87

INDEX TO VOLUME TI.

Coronoid—continued.
process of lower jaw, 55
of ulna, 89
Corpus cavernosum, artery of, 447
Corrugator supercilii muscle, 267
Coste or ribs, 27
of scapula, 83
Costal cartilages, 29
Costo-central articulation, 140
Costo-clavicular ligament, 146
Costo-coracoid membrane and ligament,
193
muscle, 261
Costo-sternal articulations, 142
Costo-transverse articulation, 141
Costo-xiphoid ligaments, 142
Cotunnius, nerve of, 541
Cotyloid (kotvAn, a cup; eldos, shape)
cavity, 9
of pelvis, 103
ligament, 164
CRANIAL NERVES.
NIAL.
Cranial arteries, 366
cavity, 62
ganglia, 628
plexus, 628
sinuses, 481
Cranio-facial axis, bones forming, 74
Cranio-vertebral muscles, 305
Cranium (kpavioy, the skull), 31. See
Skull.
lymphatics of, 517
venous circulation in, 480
Cremaster (kpeudw, I suspend), 318
Cremasteric artery, 452
fascia, 320
Crest of bone, 8
external occipital, 33
nasal, 47
of ilium, Ior
of os pubis, 103
sphenoidal, 42
Cribriform (cribrum, a sieve; forma,
shape) fascia, 226
lamella of ethmoid bone, 46
of temporal bone, 40
Crico-thyroid artery, 363
Crista frontalis, 36
galli (cock’s comb), 45
ilii, IOT
Crucial (crux, a cross) ligaments, 168
Cruciform ligament, 138
Crura of diaphragm, 309
Crural (crus, a leg) arch, 324, 341
canal, 227, 341
nerve, 602, 604
ring, 324
septum, 341
sheath, 227
Crureus muscle, 239
Cubo-cuneiform articulation, 178
Cuboid (xvBos, a cube; eidos, shape)
bone, 116
homology of, 127

Sce NERVES, Cra-

003

Cuboid bone—continued.
ligaments of, 176, 177
ossification of, 122
Cucullaris (cucwllus, a hood) muscle,
187
Cuneiform (cuneus, a wedge; forma,
shape) bones of foot, 115
homology of, 129
ligaments of, 179
ossification of, 122
of hand, 91
homology of, 127
ossification of, 100
Curvator coccygis muscle, 329
Cutaneous nerve. See NERVES.
Cylindrical bones, 8
Cystic (kvoris, a bladder) artery, 427
plexus, 640
veins, 501

Danrtos (aptés, the skin of scrotum ;
dépw, I flay). 314
Daubenton’s occipital angle, 79
Deltoid (AéAta, the letter A, or delta ;
eidos, shape) ligament, 173
muscle, 199
Dental artery, 371
canal, 54
foramen, 54
groove, 71
nerves, anterior, 539
inferior, 545
posterior, 538
veins, 477
Dentated suture, 131
Depressor alse nasi, 470
anguli oris, 274
labii inferioris, 274
Dermal (5€pua, skin) skeleton, 7
Descendens noni nerve, 567
Diaphragm (dd, between ;
fence) 308
action of, 313
pelvic, 329
Diaphragma oris, 283
Diaphragmatic nerve, 578
plexus, 639
veins, 474
Diaphysis (dé, between ; vw, I grow), &
Diapophysis (i, apart ; apophysis), 10,
24
of cervical vertebra, I1
Diarthrosis (6:4, between ; &p@por, a joint),
132
Digastric (Sis, twice; yaornp, a belly)
fossa, 39, 62
muscle, 281
nerve, 550
Digital arteries of foot, 467, 471
of hand, 412
fossa of femur, 107
nerves in foot,
623

gpicow, ©

618, 619, 620,

in hand, 590, 591, 593, 623
phalanges, 94.

654

Dilatator naris, 270
Diploé (SrAdos, double), 62
veins of, 485
Dolichocephalic (SoArxds, long; Keport,
the bead) skulls, 79
Dorsal artery. See ARTERY.
fascia, 299
of foot, 245
ligaments. See LIGAMENT
muscles, 297
nerves of foot, 623
of hand, 588, 623
of penis, 611
spinal, 574, 593
veins of penis, 500
spinal, 492
vertebrae, 12
Dorsi-lumbar (dorsuni, the back;
bus, the loin) nerve, 598
Dorsi-epitrochlearis muscle, 207
Dorso-lateral muscles, 185, 332
Dorsum sell (back of the saddle), 42
Douglas, semilunar fold of, 318
Duodenal veins, 501
Durei’s researches in the arteries of the
brain, 378

lum-

Ean, muscles of, 265
Kjaculator urine muscle, 330
Elbow-joint, 152
ligaments of, 152
movements of, 154
nerves of, 588
Eminence, frontal, 35
illio-pectineal, 103
jugular, 33
parietal, 34
Eminences of bones, 8
condylar of humerus, 86
Emulgent (emulgeo, I milk or drain out),
arteries, 432
veins, 494
Enarthrosis (év, in; &p@pov, a joint), 132
Endoskeleton (€5ov, within ; skeleton), 7
Ensiform (ensis, a sword ; forma, shape),
process of sternum, 26, 26
Epaxial (éf, on; avis) muscles, 185,
260
Epicondyle (emi, on; condyle), 86
Epicranial (éri, on; kpavioy, the skull)
muscles, 264
Epigastric (émi, on; -yaornp, the stomach)
artery. See ARTERY.
plexus, 639
veins, 496, 498
Epihyal (émi, on; hyoid bone) bones, 74
145 _
Epiotic (eri, on; ods, gen. wTds, the ear)
centre, 69
Epiphysis (et, on; vw, I grow), 8
Episkeletal (émf, on; skeleton) muscles,
185
Epitrochlea (emt, on; trochlea), 86
LEpitrochleo-anconeus muscle, 207

INDEX TO VOLUME If.

Erect attitude, adaptation of skeleton to,
122
Erector clitoridis, 331
penis, 330
spine, 299
Ethmo-cranial angle, 80
Ethmoid (j@u0s, a sieve; eldos, shape)
bone, 45
ossification of, 71
Ethmoidal artery, 375
cells or sinuses, 45, 67
spine, 42
Ethmo-turbinals, 45, 74
Eustachian canal, 40
tube, 62
Exoccipitals, 33, 74
Hxoskeleton (e&w, without; skeleton), 7
Expiration, physiology of, 313
Extension, 132
Extensor muscles of hand and fingers,
216, 220
of foot and toes, 245
Extrinsic (extrinsecus, outward) muscles,
185
Eyeball, movements of, 277
Kyelids and eyebrows, muscles of, 265
nerves of, cutaneous, 622
muscular, 624

Facr, lymphatics of, 513
muscles of, 274
nerves of, cutaneous, 622
muscular, 624
veins of, 475, 477
Facial angle, 79
artery, 364.
nerves, 548, 578
veln, 475
Falciform (falz, asickle or scythe ; forma,
shape) border of fascia lata, 277
process, 162
sinus, 482
Fallopius, aqueduct of, 40
hiatus of, 40
Fascta (a band), 185
abdominal, 314, 324
anal, 326
of arm, 204
axillary, 193
cervical, deep, 291
of Colles, 325
cremasteric, 320
cribriform, 226
deep, 186
dorsal, 299
of foot, 245
of fore-arm, 208
hand, 208, 209
head and neck, 264
hip and thigh, 226
iliac, 324
infundibuliform, 324, 336
intercolumnar, 317
lata (broad fascia), 226
of leg, 243

INDEX TO VOLUME I.

Tascra—continued.

of lower limb, 226

lumbar, 299

masseteric, 278, 201

obturator, 327

of orbit, 278

parotid, 291

of pectoral region, 193

pelvic, 326

perineal, 325

plantar, 255

prevertebral, 292

propria, femoral, 342

recto-vesical, 326

of shoulder, 199

subpubic, 325

superficial or subcutaneous, 186

temporal, 279

of thigh, 226

transversalis, 324

triangular, 316

of trunk, anterior, 193
posterior, 187
homologies of, 332

of upper limb, 187

Fauces (the threat), isthmus of, 289
pillars of, 288

Femoral (femur, the thigh) artery, 453

See ARTERY
canal, 227, 341
hernia, 340
ligament, 227
muscles, anterior, 234
internal, 240
; posterior, 232
ring, 341
vein, 497
vessels, sheath of, 227
Femur, 107
compared with humerus, 126
ossification of, 119
Fibro-cartilage, intervertebral, 133
of knee, 169
of lower jaw, 145
pubic, 163
radio-ulnar, 150
scapulo-clavicular, 147
sterno-clavicular, 146
Fibula (a brace, a clasp), 112
ligaments of, 172
ossification of, 119
Fingers, bones of, 94
ossification of, 100
muscles of, 221
Wissure of bone, 9
of Glaser, 39, 40
incisor, 71
pterygo-maxillary, 60
sphenoidal, 44, 60, 65
position of nerves in, 530
spheno-maxillary, 60
Flat bones, 8
Flexion, 132

Flexor muscles of foot and toes, 252-258
of hand and fingers, 211-214, 22

4

Floating ribs, 27

655

Flower, homologous parts of scapula and

Toetal development, 2

Yontanelles ( fons, a fountain), 68

Foot, arteries of, dorsal, 469

plantar, 465

articulations of, 174

bones of, 114, 117
compared with hand, 129
ossification Of Tre

fascia of, 245, 255

muscles of, 256, 263

nerves of, cutaneous, 623, 624
muscular, 626

ilium, 129
!

Foramen ( foro. I pierce) of bone, 9

cecum of frontal bone, 37, 64

carotid, 40, 62

dental, inferior, 54

incisor, 47

infraorbital, 48, 59

jugulare, 62

labial, 54

lacerum anterius, 65
jugulare, 33
medium, 62
orbitale, 44
posterius, 62, 65

magnum, 31, 62, 65

| mastoid, 39

mental, 54, 59

obturator, 100, 103

occipital, 31, 65

opticum, 44, 60, 65

ovale of pelvis, 100, 163

ovale of sphenoid, 44, 62, 65

palatine, anterior, 47, 62
posterior, 62

parietal, 34

quadratum, 311

rotundum, 44, 61, 65

spheno-palatine, 50, 61
spinosum, 44, 62, 65
sternale, 31
stylo-mastoid, 40, 62
supraorbital, 35, 59, 60
thyroid, 100, 103

of a vertebra, Io

posterior, 33
of diaphragm, 311
of ethmoid bone, 60
intervertebral, 10
malar, 52, 59

ternal, 36

palatine, small, 50, 62

sacral, anterior, 15
posterior, 16

of Searpa, 48 |

| of Stenson, 47

Tore-arm, aponeurosis of, 208
arteries of, 407
articnlations of, 150

sacro-sciatic, great and small, 162

Foramina, condylar, anterior, 33, 62, 65

orbital, anterior and posterior in-

656 INDEX TO
Fore-arm—continued.
bones of, 87
compared with leg, 126
ossification of, 97
fascia of, 208
muscles of, 208
nerves of, cutaneous, 623
muscular, 625
Form, symmetry of, 5
Fossa of bone, 9
canine, 48, 58.
coronoid, 87
digastric, 39, 62
digital, 107
glenoid, 39, 60
guttural, 62
shiac, 102
incisor of upper jaw, 48, 58
of lower jaw, 54
infraspinata, $1
intercondylar, 109
ischio-rectal, 327
jugular, 40
lachrymalis, 36, 60
myrtiform, 48
navicular, 44
olecranon, 87
pituitary, 42
pterygoid, 44
spheno-maxillary, 60
subscapularis, 81
supraspinata, $1
temporal, 60
trochanteric, 107
zygomatic, 60
Fossze, nasal, 65
occipital, superior and inferior, 33
of skull, internal, 63
Fovee (pl. of fovea, a pit or depression),
glandulares, 35
Frontal (frons, the forehead) artery, 377
bone, 35, 74
ossification of, 68
eminence, 35
nerve, 534, 535
sinus, 36, 67
suture, 37, 58, 68
vein, 475
of diploé, 485
Frontalis muscle, 264
Fronto-parietal suture, 57
Furrow of bone, 9

GANGLIA, of cardiac nerves, 639
cranial, 628
of glosso-pharyngeal nerve, 555
lumbar, 636
meseraica, 640
of pneumo-gastric nerve, 559
sacral, 637
semilunar, 639
of spinal nerves, 569

sympathetic nerves, 626

thoracic, 633

VOLUME 1.

Gangliated cord, sympathetic, 626
cervical part, 628
connections with cerebro-spinal sys
tem, 627
lumbar part, 636
sacral part, 636
thoracic part, 633
GANGLION, Arnold’s, 546
basal optic, 528
Bochdalek’s, 539
cervical, lower, 633
middle, 632
upper, 628
ciliare, 536
diaphragmaticum, 639
on facial nerve, 548, 549
of fifth pair, or Gasserian, 533
geniculate, 548
impar, 637
intercaroticum, 632
jugular, 555
lenticular, 536
Meckel’s, 540
nasal, 540
| ophthalmic, 536
otic, 546
petrous, 555
semilunare (Gasserian), 533
semilunare (ophthalmic or lenti
cular), 536
spheno-palatine, 540
splanchnico-suprarenale, 639
submaxillary, 547
thyroideum, 632
of Wrisberg, 638
Gasserian ganglion, 533
Gastric (yaorhp, the stomach) artery, 428
nerve, 564
Gastrocnemius (yaornp, the belly ; nvjun,
the leg) muscle, 249
Gastro-duodenal (yaorjp, the stomach ;
duodenum) artery, 425
plexus, 640
Gastro-epiploic (yaorhp, the stomach ;
éxizAooy, the omentum) arteries,
425, 428
plexus, 640
vein, 501
Gegenbaur, homologies of carpus and
tarsus, 127, 129
Gemelli (twin) muscles, 231
Geniculate ganglion, 548
Genial (yéveiov, the chin) tubercles, 284
Genio-glossus (yévevor, the chin ; yAaéooa,
the tongue) muscle, 285
Genio-hyo-glossus (yéveiov, the chin ;
boedns, hyoid bone ; yA@oou, the
tongue) muscle, 285
Genio-hyoid (yeveiov, the chin ; docd%s,
hyoid bone) muscle, 284
Genital nerve, 602
Genito-crural nerve, 601
Genito-urinary muscles, 329
Gimbernat’s ligament, 316
| Ginglymus (ylyyAupos, a hinge), 132

INDEX TO

Girdles, shoulder and pelvic, comparison
of, 123
Glabella (dim. of glabra, fem. of glaber,
smooth), 35
Glands, Lymphatic.
Glands.
Glaser, fissure of, 39, 40
Glenoid (yAnvn, a shallow pit of a bone ;
eidos, shape) cavity, 9
of scapula, $3
fossa of temporal bone, 39, 60
ligament, 149
Gliding, 133
Glosso-pharyngeal (yAéooa, the tongue ;
gdpuyé, the pharynx) nerve,
554
ganglia of, 555
Gluteal artery, 448
nerve, inferior, 613
superior, 607
Glutei (yAoutéds, the buttock) muscles, 228
Gomphosis (yéuos, a nail), 131
Gracilis (slender) muscle, 240
Groove, bicipital, 86
of bone, 9
dental, 71
for Eustachian tube, 62
lachrymal, 48, 60
mylo-hyoid, 55
occipital, 39
scapular, 83
spiral, 86
subcostal, 28
Gustatory (gusto, I taste) nerve, 544
Guttural (guttwr, the throat) fossa, 62

See Lymphatic

HMAL (aiua, blood) septum, 332
Hemorrhoidal (aiua, blood ; péw, I flow)
artery, Inferior, 445
middle, 441,
superior, 430, 432
nerves, inferior (pudic), 612
(sympathetic), 642
superior, 642
plexus, 498
Hamstring muscles, 232
Hamular process, of sphenoid bone, 44
Hamulus (dim. of hamus, a hook)
lachrymalis, 53
Hand, arteries of, 411, 415
varieties of, 419
articulations of, 154
bones of, 90
ossification of, 100
compared with foot, 127
fasciz of, 208, 209
muscles of, 221, 263
action and varieties of, 22
nerves of, cutaneous, 623
muscular, 626
Harmonia (apud(@, I fit together), 131
Haunch, 100
Head, bones of, 31
homologies of, 73

VOL. I.

VOLUME I. 657

Head—continued.
bones of, morphology of, 73
ossification of, 67
nerves of, cutaneous, 622
muscular, 624
typical component parts of, 74
Head of a bone, 8
Head and neck, fascie and muscles of,
264
lymphatics of, 516
veins of, 475
| Heart, arteries of, 353
lymphaties of, 514
| nerves of, 561, 650, 632, 638
veins of, 503
Heel, 114
Hepatic (fap, the liver) artery, 425
plexus, 640
veins, 494
Hernia (épvos, a branch), congenital, 338
femoral, 340
infantile, 338
inguinal, 335
direct or internal, 338
in female, 340
oblique or external, 337
in female, 338
varieties of, 336
scrotal, 337
surgical anatomy of, 335
tunice vaginalis, 338
umbilical, 335
ventro-inguinal, 338
Hesselbach, triangle of, 339, 340
Hiatus (an opening, from fio, v. n., I
open) aorticus, 311
Fallopu, 40
interosseus, I51
Highmore, antrum of, 49
Hip-joint, 163
ligaments of, 164
movements of, 166
muscles of, 228
nerves of, 603, 604, 615, 624
Hip and thigh, fascia of, 226
Histology (iotés, a web; Adyos, dis-
course), I
Homologies of bones of head, 73
carpus and tarsus, Gegen-
baur's table, 129
fasciv and muscles of trunk
and head, 332
hand and foot, 127
muscles of limbs, 262
scapula and ilium, Flower’s
table, 129
shoulder and pelvic gir-
dles, 123
upper and lower limbs,
123, 124, 129
vertebrae, 22
Homology (éuds, the same ; Adyos, pro-
portion), 5
Homotypy (6ués, the same; tvmos, a
type or model), 5

UG

658 INDEX TO VOLUME I.

Humeral artery, 399
of acromio-thoracic, 395
transverse, 387
Humerus (the shoulder), 85
compared with femur, 126
ossification of, 97
Hunter’s canal, 455
Hyoglossus (doedjs, hyoid bone ; yA@ooa,
tongue) muscle, 285
Hyoid arteries, 363
Hyoid (uv, the letter wpsilon ; & os, shape)
bone, 55
ossification of, 73
Hypapophysis (éré, under ; apophysis),
2A, 12
Hypaxial (rd, under; axis) muscles,
185, 333 ;
Hypogastric (id, under; yaorhp, the
stomach) artery, 440
nerve, 600
plexus, 641
Hypoglossal (id, under ; yA@ooa, the
tongue) nerve, 565
Hyposkeletal (676, under ; skeleton) mus-
cles, 185
Hypothenar (iad, under ;
palm), eminence, 222

Gévap, the

ILEO-COLIC artery, 430
Iliac artery, common, 437
external, 450
internal, 439
fascia, 324
fossa, 102
lymphatic glands, 508
nerves, 600
portions of fascia lata, 227
veins, 498
Tliacus (iia, the flank) muscle), 234
Ilio-aponeurotic muscle, 235
Tlio-capsularis muscle, 234
Jlio-costalis muscle, 300
Tlio-femoral ligament, 165
Tlio-hypogastric nerve, 600
Tlio-inguinal nerve, 600
Ilio-lumbar artery, 448
ligament, 159
Ilio-pectineal eminence, 103
line, 102
Tlio-psoas muscle, 234
Tlio-tibial band, 226
Tlio-trochanteric ligament, 165
llium (idia, the flanks), ror
homology of, 123, 124, 129
ossification of, 118
Incisor foramen, 47
fissure, 71
fossa, lower jaw, 54
upper jaw, 48, 58
nerve, 545
Incisura (notch), 9
of acetabulum, 103
ethmoidalis, 35
semilunaris, of sternum, 26
Incus (an anvil), 74

Indicator muscle, 220
Infantile hernia, 338
Inframaxillary nerve, 552
Infraorbital artery, 371
canal, 49, 60
foramen, 48, 59
nerves, 539, 551
plexus, 540
veins, 476
Infraspinata fossa, 81
Infraspinatus muscle, 200
Infraspinous artery, 389
Infratrochlear nerves, 535, 536
Infundibuliform fascia, 324, 336
Infundibulum (funnel) of ethmoid bone,
46
Ingrassias, wings of, 43
Inguinal (tnguen, the groin), canal, 335
hernia, 335. Sce Hernia
lymphatic glands, 507
Innominate artery, 355
bone, 100
ossification of, 118
veins, 473
Insertion of muscles, 184
Inspiration, movements of, 312
Interaccessorii muscles, 304
Interarticular fibro-cartilages and liga-
ments. See the various joints
Intercarotic ganglion, 632
Interelavicular notch, 26
ligament, 146
Intercolumnar fascia, 317
Intercondylar fossa, 109
Intercostal arteries, 391, 392, 420
lymphatics, 513, 514
muscles, 306
actions of, 312
nerves, 593, 597
veins, 474
Intercosto-humeral nerve, 597
Intermaxillary bone, 72, 74
Intermetacarpal articulations, 157
Intermuscular septa. Sce Septa.
Internodia (infer, between; nodits,
knot), 94
Interossei muscles of hand, 222
of foot, 258
Interosseous arteries of arm, 408
of foot, 470
of hand, 409, 417,
419
ligament. See LIGAMENTS.
nerves, 591, 594, 621
Interparietal bones, 74
suture, 58
Interphalangeal articulations, hand, 159
toes, ISI
Interspinales muscles, 304
Interspinous ligaments, 137
Intertransversales muscles, 304
Intertransverse ligaments, 137
Intertrochanteric line, 108
Intervertebral discs, 133, 160
foramina, 10

INDEX TO VOLUME I. 659

Intrinsic muscles, 185, 261 Leg, aponeurosis of, 243
Trregular or mixed bones, 8 articulations of, 172
Ischio-capsular ligament, 165 bones of, 110, 112
Ischio-cavernosus muscle, 330 muscles of, anterior, 243
Ischio-rectal fossa, 327 external, 248
Ischium (icxfoy, the hip), 103 posterior, 248
homology of, 123 nerves of, cutaneous, 623
ossification of, 118 muscular, 626
Isthmus of the fauces, 289 Lenticular (dim. from Jens) ganglion,
536
JACOBSON’S nerve, 556 Levator. Sce MuscLes
Jaw, lower, 53, 74 Ligamenta arcuata, 309
articulation of, 144 subflava, 136
muscles of, 281 vaginalia, 212
action of, 284 LIGAMENTS (/igo, I bind), acromio-clavi-
ossification of, 72 cular, 147
upper, 46 alar, 170
ossification of, 71 alar odontoid, 139
Joint, ankle, 173 of ankle, 173
elbow, 152 annular, 244
hip, 163 astragalo-caleaneal, 175
knee, 166 astragalo-scaphoid, 176
shoulder, 148 atlanto-axial, 140
wrist, 154 of atlas, transverse, 138
See ARTICULATION of bladder, true, 326
Joints, motions of bones in, 134 caleaneo-cuboid, 176
various forms of, 131 calcaneo-fibular, 174
Jugular eminence, 33 calcaneo-scaphoid, 175
foramen, 62 carpal, 156
fossa, 40 annular, 208, 209
ganglion, 555 carpo-metacarpal, 157
notch, 33 of coceyx, 160
veins, 477, 479, 489 conoid, 147
Jugulo-cephalic vein, 487 coraco-acromial, 148
coraco-clavicular, 147
Kuipney, lymphatics of, 512 coraco-humeral, 149
Knee-joint, 166 coracoid, 148
ligaments of, 166 costo-central, anterior, 140
movements of, 171 costo-clavicular, 146
nerves of, 603, 605, 616, 619 costo-coracoid, 193
Knee-pan, 110 costo-sternal, 142
costo-transverse, I4I
LABIAL artery, 365 costo-xiphoid, 142
foramen, 54 cotyloid, 164
nerve of inferior dental, 545 erucial, 168
infraorbital, 539 | cruciform, 138
veins, 476 ceubo-cuneiform, 178
Lachrymal artery, 375 of cuboid bone, 176, 177
bone, 52, 74 of cuneiform bones, 179
ossification of, 72 deltoid, 173
fossa, 36, 60 of elbow, 152
eroove, 48, 60 femoral, 22
nerve, 534 of foot, 174
Lacteals (Jac, milk), 509 of forearm, 150
Lambdoidal (A, the letter Jambda ; etSos, | Gimbernat’s, 316
shape) suture, 57 glenoid, 149
Lamella, cribriform, 45, 46 of hand, 154
Lamina of a vertebra, 10 of hip-joint, 163
cribrosa of temporal bone, 40 ilio-femoral, 165
Lamine or plates of vertebra, 10, 11, ilio-lumbar, 159
Toa ilio-trochanteric, 165
Laryngeal arteries, 363, 387 interclavicular, 146
nerves, 561, 624 interspinous, 137
veins, 479 intertransverse, 137
Latissimus dorsi muscle, 189 ischio-capsular, 165

= uUaz

660 INDEX TO VOLUME I.

LIGAMENTS—continued.
of knee-joint, 166
of lower limb, 163
metacarpal, 157
of thumb, 158
metacarpo-phalangeal, 158
metatarsal, 180
transverse, 181
metatarso-digital, 181
obturator, 163
occipito-atlantal, 140
occipito-axial, 140
odontoid, alar, 139
middle, 140
orbiculur, 150
palmar, 156, 157, 158
of patella, 167
lateral, 170
of pelvis, 159
of phalanges, fingers, 159
toes, IST
Poupart’s, 316
pterygo-maxillary, 272
pubic, 163
pubo-femoral, 165
radiated, of ribs, 140
radio-carpal, 154
radio-ulnar, 150
rhomboid, 146
of ribs, 140
round, radio-ulnar, 15%
of hip, 165
sacro coccygeal, 160
sacro-iliac, 161
sacro-sciatic, 162
sacro-vertebral, 159
scapho-cuboid, 177
scapho-cuneiform, 178
of seapula, 148
scapulo-clavicular, 146
of shoulder-joint, 148
stellate, 140
of sternum, 142
sterno-clavicular, 146
stylo-hyoid, 55,145
stylo-maxillary, 145, 278
subpubic, 163
suprascapular, 148
supraspinous, 137
suspensory of penis, 314
talo-scaphoid, 176
tarsal, 174
tarso-metatarsal, 179
temporo-maxillary, 144
tibio-fibular, 172
transverse of atlas, 138
of acetabulum, 165
metacarpal, 157
metatarsal, 181
of toes, 256
trapezoid, 147
of upper limb, 146
of urethra, triangular, 325
vertebral, 133
of wrist, 154

Ligamentum arcuatum externum, 309
arcuatum internum, 309
breve (of fingers), 212
cruciatum cruris, 244
mucosum, 170
nuchx, 137
patellee, 167
suspensorium dentis (of the odon-
toid process), 140
teres of hip-joint, 165
transversum cruris, 244
Limb, lower, articulations of, 163
bones of, 100
ossification of, 118
fascie of, 226
lymphatics of, 506
muscles of, 226, 263
nerves of, cutaneous, 623
muscular, 626
veins of, 495
upper, articulations of, 146
bones of, 81
ossification of, 95
fascive of, 187
lymphaties of, 514
muscles of, 187, 262
nerves of, cutaneous, 623
muscular, 625
veins of, 485
Limbs, distinctive characters of, in man,
130
homological comparison of, 122
homologous bones, tables of, 129
homology of muscles of, 262
morphology of bones of, 122
of muscles, 260
relation to axial skeleton, 122
Line, curved ofilium, 101, 102
occipital, 33
ilio-pectineal, 102, 103
intertrochanteric, 108
oblique of lower jaw, 54
popliteal, 111
Linea alba, 322
aspera, 108
Line semilunares, 322
transverse, 320
Lingual artery, 363
nerve, of fifth, 544
of glosso-pharyngeal, 556
vein, 479
Lingula sphenoidalis, 42
Lips, muscles of, 270
Liver, lymphatics of, 511
Long or cylindrical bones, 8
Longissimus dorsi muscle, 300
Longus colli muscle, 296
Longitudinal sinuses, superior and in-
ferior, 482
Lumbar aponeurosis or fascia, 187,
299
arteries, 436
ganglia, 636
lymphatic glands, 509
nerves, anterior division of, 58S

INDEX TO VOLUME I.

Lumbar— continued.
nerves, Reser es 574
fifth, 607
plexus, 598
veins, 494
vertebree, 13
Lumbo-inguinal nerve, 603
Lumbo-sacral nerve, 607
Lumbrieales (lwmbricus, an earthworm)
muscles, of foot, 253
of hand, 213
Lungs, lymphatics of, 514
Lymphatic duct, right, 504, 506
glands, 504
axillary, 515
bronchial, 513
cardiac, 513
cervical, 516
iliac, 508, 509
inguinal, 507
intercostal, 513
lumbar, 509
mediastinal, 513
mesenteric, 509
cesophageal, 513
popliteal, 506
sacral, 509
of thorax, 512
LYMPHATICS, Descriptive Anatomy of,

504
of aueonen and pelvis, 508, 509
back, 516
bladder, 512
cranium, 517
face, 518
head and neck, 516
heart, 514
intercostal, 514
of kidneys, 512
limb, lower, 506
deep, 508
superficial, 507
upper, 514
superficial, 516
deep, 516
liver, 511
lungs, 514
occipital, 517
of esophagus, 514
pancreas, 511
penis, 508
pia mater, 518
rectum, 511
scrotum, 508
spleen, 511
sternal, 513
of stomach, 511
suprarenal capsules, 512
temporal, 517
of testicle, 512
thorax, 512, 513
thymus gland, 514
trunk, lower half, 508
ureter, 512
uterus, 512

661

Maar (mala, the cheek) arch, 60
arteries, 375
bone, 51, 74
ossification of, 72
foramina, 52, 59
nerve, of facial, 551
of orbital, 538
process, 48
Malleolar (malleolus, the ankle) arteries,

469
Malleolus (dim. of malleus, a hammer ;
the ankle), external, 113
internal, 112
Mammary (mamma, the breast) artery,
external, 395
internal, 390
vein, internal, 474
Mammillary (mammitla, a nipple) pro
’ cesses of vertebrae, 15, 24
Mandible, 53, 7
Manubrium (a handle) of sternum, 25
Marrow of bone, 7
Martins on homologies of limbs, 126
Masseter (uaoodoua, I chew) muscle, 278
Masseteric (masscter) artery, 371
fascia, 278, 291
nerve, 543
vein, 476
Mastication, muscles of, 278
Mastoid (uacrds, a nipple; «léos, form)
artery,{366
foramen, 39
portion of temporal bone, 37, 39
process, 39
Mastoido-humeral muscle, 292
Maxillary (mawilla, a jaw) artery, in-
ternal, 369, 373
superior, 371
bone. See Jaw.
nerve, inferior, 533, 542
superior, 533, 537
sinus, 49, 66, 67
vein, internal, 477
Maxillo-turbinal bone, 53, 74
Meatus (meo, I pass), 9
auditorius, 40
of nose, 46, 66
Meckel’s ganglion, 540
Median artery, 409, 411
anterior, 385
basilic (BaciAuxds, royal) vein, 487
cephalic (kepadn, the head) vein,
487
cutaneous vein, 487
line, 6
nerve, 590
vein, deep, 487
Mediastinal arteries, 391, 420
lymphatic glands, 513
veins, 474
Medulla (marrow) of bones, 7
Membrana sacciformis, 151
Membrane, costo-coracoid, 193
Meningeal arteries. See ARTERY.
vein, middle, 477

662 INDEX TO VOLUME I.

Mental (mentum, the chin) foramen, 54,
59
nerve, 545
vein, 476
Mento-hyoid muscle, 282
Mesenteric (uéoos, middle ; evrepov, mtes-
tine) artery, inferior, 430
superior, 428
glands, 509
plexus, inferior, 641
superior, 640
veins, inferior, 502
superior, 501
Mesial (uéoos, middle) plane, 5, 6
Mesosternum (uéoos, middle ; o7épvoy,
the chest), 25, 26
Metacarpal arteries, 409, 417
Metacarpo-phalangeal articulations, 158
Metacarpus (wera, beyond ; kaprds, the
wrist), 93
articulations of, 157
ossification of, 100
Metapophysis (uet¢, beyond ; apophysis),
ise 22
Metasternum (wera, beyond ; otépyor,
the chest), 25, 26
Metatarsal artery, 470
articulations, 180
Metatarso-digital articulations, 181
Metatarsus (uetd, beyond ; tapads, the
instep), 116
ossification of, 122
Midriff (Sax. midd, middle ; hrif, the
belly), 308
Morphology (uopp7, form; Adyos, dis-
course), 2
of bones of head, 73
of limbs, 122
of fascie of trunk and head, 332
of muscles of limbs, 260
of trunk and head, 332
Motorius oculi nerve, 528
Mouth, muscles of, 270
Movement, various kinds of, 132
Movements of ankle-joint, 174
clavicular, 148
of elbow, 154
foot and toes, 182
hip, 166
knee, 170
lower jaw, 145
occipito-vertebral, 140
of patella on femur, 171
of pelvis, 163
radius on ulna, 151
ribs, 143
shoulder, 150
vertebral column, 137
wrist and fingers, 159
Multifidus (multus, many ; findo, I cleave)
spine muscle, 303
Muscues, Descriptive Anatomy of, 183
abductor brevis pollicis, 221
abductor indicis, 223
abductor longus pollicis, 218

Muscies—continued.

abductor minimi digiti (hand), 222
minimi digiti (foot), 257
ossis metacarpi minimi digiti
(hand), 257
pollicis (hand), 221
pollicis pedis, 257
accessorius ad ilio-costalem, 300
adductor brevis, 241
gracilis, 240
longus, 241
magnus, 241
minimus, 243
pollicis mantis, 222
pollicis pedis, 258
anconeus, 207
anomalus, 270
attollens auriculam, 265
attrahens auriculam, 205
auricularis, superior, anterior, et
posterior, 265
azygos pharyngis, 288
uvule, 289
biceps flexor cruris, 232
flexor cubiti, 205
biventer cervicis, 301
brachialis anticus, 206
brachio-radialis, 206
buccinator, 272
bulbo-cavernosus, 330
caninus, 271
cephalo-pharyngeus, 285
cervicalis ascendens, 300
cireular of Santorini, 330
circumflexus palati, 290
coceygeus, 329
complexus, 301
compressor hemispheriam bulbi, 330
compressor naris, 269
compressores vene dorsalis penis, 33°
constrictor of pharynx, inferior, 250
middle, 287
superior, 288
isthmi faucium, 289
urethra, 330
coraco-brachialis, 204
corrugator supercilii, 267
cremaster, 315
crureus, 239
cucullaris (like a hood), 187
curvator coccygis, 329
deltoid, 199
depressor ale nasi, 270
anguli oris, 274
labii inferioris, 274
diaphragm, 308. See DIAPHRAGM.
diaphragma oris, 283
digastric, 281
dilatator naris anterior, 27
naris posterior, 270
dorst-epitrochlearis, 207
ejaculator urine, 330
epitrochleo-anconeus, 207
erector clitoridis, 331
penis, 330

INDEX TO VOLUME I 663

Muscies— continued. Muscies—continued.
erector spine, 299 interspinales, 304
extensor brevis digitorum pedis, 247 intertransversales, 304
brevis hallucis, 247 ischio-cavernosus, 330
carpi radialis brevior, 216 latissimus dorsi, 189
carpi radialis longior, 216 levator anguli oris, 271
carpi ulnaris, 218 anguli seapule, 192
coccygis, 305, 329 ani, 328, 331
communis digitorum, 216 coccygis, 329
indicis, 220 labii inferioris, 274
longus digitorum pedis, 246 labii superioris proprius, 271
minime digiti, 218 labii superioris aleque nasi, 269
ossis metacarpi pollicis menti, 274
(hand), 218 palati, 289
(foot), 245 palpebrie superioris, 267, 275
primi internodii pollicis, 219 proprius ale nasi anterior,
(foot), 245 270
proprius pollicis, 245 proprius ali nasi posterior, 270
secundi internodii pollicis prostate, 328
(hand), 219 levatores costarum, 308
flexor accessorius, 253 : longiores costarwm, 308
brevis digitorum pedis, 256 longissimus dorsi, 300
brevis minimi digiti (hand), 222 longus colli, 296
brevis minimni digiti pedis (foot), | lumbricales (worm-shaped muscles),
258 of hand, 213
brevis pollicis mantis, 222 of foot, 253
brevis pollicis pedis, 257 masseter, 278
carpi radialis, 210 mastoido-humeral, 292
carpi ulnaris, 211 mento-hyoid, 282
digitt secundi proprius (foot), multifidus spine, 303
253 mylo-glossus, 286
digitorum profundus, 213 mylo-hyoid, 283
digitorum sublimis, 211 oblique, of eye, inferior, 277
longus digitorum pedis, 252 superior, 275
longus pollicis mantis, 214 obliquus abdominis externus, 315
longus pollicis pedis, 253 | internus, 317
pertorans digitorum mantis, 213 capitis inferior, 305
perforans digitorum pedis, 252 superior, 305
perforatus digitorum mantis, 211 obturator externus, 231
perforatus digitorum pedis, 256 internus, 230
frontalis, 264 occipitalis, 264
gastrocnemius, 249 occipito-frontalis, 264
gemelli, 231 omo-hyoid, 294
genio-glossus, 285 opponens hallucis, 258
genio-hyo-glossus, 285 minimé digiti (foot), 258
genio-hyoid, 284 opponens minimi digiti (hand), 222
gluteus maximus, 228 pollicis, 222
medius, 228 orbicularis oris, 271
minimus, 229 palpebrarum, 266
gracilis, 240 palato-glossus, 289
hyo-glossus, 285 palato-pharyngeus, 289
iliacus, 234 palmaris brevis, 221
wiacus minor, 234 longus, 210
ilio-aponeurotic, 235 pectineus, 241
ilio-capsularis, 234 pectoralis major, 193
ilio-costalis, 300 minor, 196
ilio-psoas, 234 peroneo-calcaneus internus, 254
incisivi, 271 peroneus brevis, 248
indicator, 220 longus, 248
infraspinatus, 200 tertius, 246
intercostal, external, 306 peroneus accessorius, 248
internal, 306 quartus, 248
action of, 312 quinti digiti, 248
interossei, of hand, 222 plantar, 255

of foot, 258 plantaris, 252

INDEX TO VOLUME I.

Muscies—continued.

platysma myoides, 272, 290
popliteus, 252
pronator radii quadratus, 214
radii teres, 209
psoas magnus, 234
parvus, 235
pterygoid external, 280
internal, 279
pterygoideus proprius, 280
pubo-urethral, 33
pubo-vesical, 33
pyramidalis abdominis, 322
pyramidalis nasi, 269
pyriformis, 230
quadratus femoris, 231
lumborum, 322
menti, 274
quadriceps extensor cruris, 237
radio-carpalis, 212
recti of eye, 275
rectus abdominis, 320
capitis anticus major, 296
capitis anticus minor, 296
capitis lateralis, 296
capitis posticus major, 305
capitis posticus minor, 305
femoris, 238
rectus sternalis, 308
retrahens auriculam, 265
rhomboideus major, 192
minor, 192
rhomboideus occipitalis, 192
risorius (smiling muscle), 272
rotatores spins, 303
sacct lachrymalis, 267
sacro-coccygeus posticus, 305
sacro-lumbalis, 300
salpingo-pharyngeus, 288
Santorini’s, circular, 330
risorlus, 272
sartorius, 236
scalenus anterior, 295
medius, 295
posticus, 296
semimembranosus, 233
semispinalis colli, 303
dorsi, 303
semitendinosus, 232
serratus magnus, 196
posticus inferior, 298
posticus superior, 298
soleus, 250
sphincter ani, external or superfi-
cial, 327
_ internal or circular, 327
oris, 271
vagine, 331
spinalis cervicts, 305
spinalis dorsi, 301
splenius capitis, 299
colli, 299
sternalis brutorum, 308
sterno-cleido-mastoid, 292
sterno-hyoid, 292

MuscLes—continued.
sterno-thyroid, 293
stylo-glossus, 286
stylo-hyoid, 283
stylo-hyoideus alter, 283
stylo-pharyngeus, 288
subanconeus, 207
subclavius, 196
subcostal, 308
suberureus, 240
subscapularis, 203
subscapulo-capsularis, 203
supinator radii brevis, 218
longus, 215
supraspinatus, 200
syndesmo-pharyngeus, 287
temporal, 279
tensor palati, 290
tarsi, 267
vagine femoris, 235
tensor trochlew, 276
teres major, 200
minor, 201
thyro-hyoid, 293
tibialis anticus, 245
posticus, 254
secundus, 255
tibio-fascialis anticus, 245
trachelo-mastoid, 300
transversalis abdominis, 320
cervicis, 300
transversalis menti, 274
transversus pedis, 258
perinei, 329; 330, 331
transversus nuchee, 265
orbite, 276
trapezius, 187
triangularis oris, 274
sterni, 308
triceps extensor cubiti, 206
triticeo-glossus, 286
trochlearis, 275
vastus externus, 238
internus, 239
Wilson's, 331
zygomaticus major, 272
minor, 272
Musctues of abdomen, 374
action of, 322
anal, 327
of arm, upper, 204
action of, 208
auricular, 265 ,
of back, 297
action of, 305
cranio-vertebral, short posterior, 305
dorso-lateral GQmorphol.), 332
epicranial, 264
action of, 265
of eyelids and eyebrows, 265
action of, 269
femoral, anterior, 234
action of, 240
internal, 240
action of, 243

INDEX TO VOLUME LI.

Muscies—continuwed.
femoral, posterior, 232
action of, 234
of foot, 256
action of, 259
of forearm, 208
action of, 224
genito-urinary, 329
hamstring, 232
of hand, 221, 263
action of, 224
varieties of, 224.
of head and neck, 264
of hip, 228
action of, 232
of hyoid bone, 281
action of, 284
hypaxial (morphol.), 185, 333
lateral (morphol. ), 334
of lee and foot, anterior, 243
external, 248
posterior, 248
action of, 259
of limb, lower, 226, 263
upper, 187, 262
of limbs, morphology of, 260
table of homologies of, 262
of little finger, 222
of lips and mouth, 270
action of, 274
of mastication, 278
action of, 281
of neck, anterior, 291
action of, 294
lateral and prevertebral, 295
action of, 297
of nose, 269
action of, 270
of orbit, 275
action of, 277
of palate, 288
action of, 290
paraxial (morphol.), 333
of perineum, 327
action of, 331
of pharynx, 286
action of, 290
plantar, short, 256
prevertebral, 296
pronators and flexors, 209
action of, 224
of shoulder, 199
action of, 203
supinators and extensors, 215
action of, 224
of thigh, 232
of thorax, 306
action of, 311
of thumb, 221
action of, 225
of tongue, 284
action of, 286
of trunk and upperlim), anterior, 193
posterior, 187
action of, 198

Mylo-hyoid (uta,

665

Muscies—continued.
ventral (morphol. ), 334
ventro-lateral (morphol.), 185, 260,
333
Musculo-cutaneous nerve of arm, 587
of leg, 619
Musculo-phrenic (musculus, muscle ;
gpnv, the diaphragm) artery, 391
Musculo-spiral nerve, 592
Mylo-glossus (uvAn, a mill, the jaw ;
yAGoou, the tongue), muscle,
286
a mill, the jaw;
hyoid bone) artery, 371
Mylo-hyoid groove, 55
muscle, 283
nerve, 545
ridge, 54
Myoides, See Platysma.
Myology (mis, a muscle; Adyos, dis-
course), 183
Myotome (us, a muscle; teuyw, I di-
vide), 185
Myrtiform (uvprov, a myrtle-berry ; for-
ma, shape) fossa, 48

Nanes (nostrils), 48, 58
posterior, 62
septum of, 65
Nasal (asus, the nose), aperture, 58
arteries, 365, 373, 377
bone, 52, 74
ossification of, 72
canal, 48
fosse, or cavities, 65
ganglion, 540
nerves. See NERVES
process, 48
spine, 36, 47
vein, 476
Naso-palatine nerve, 541
National differences in skull, 78
Navicular (navicula, a small ship or
boat) bone of foot, 115
homology of, 128
fossa, 44
Neck, of a bone, 8
Neck, fascie of, 291
muscles, anterior, 291, 292
lateral and prevertebral, 295
veins of, 475
Nerves, Descriptive Anatomy of,
abdominal of ilio-hypogastric,
abducent, 519, 547
accessory, spinal, 564
obturator, 604
articular of elbow-joint, 588
of hip-joint, 603, 604, 615
knee, 603, 605, 616, 619
shoulder-joint, 583, 585
temporo-maxillary joint, 544
wrist, 588
auditory, 548, 553
auricular, of auriculo-temporal, 543
great, 577

519
600

666 INDEX TO VOLUME I.

NERVES—continued. NERVES— continued,
auricular, posterior, 550 facial, 548
of pneumogastric, 560 summary of, 552
of great occipital, 573 of great auricular, 578
of small occipital, 578 of femoral artery, 604
auriculo-temporal, 543 frontal, 534
buccal of facial, 551 external, 535
of inferior maxillary, 543 internal, 534
cardiac, lower, 633 gastric, 564
middle, 632 genital, 602
of pneumogastric, 561 genito-crural, 601
upper, 631 glosso-pharyngeal, 554
carotid of petrous ganglion, 556 summary of, 556
of Vidian, 542 - gluteal, inferior, 613
cavernous of penis, 642 superior, 607
cervical, divisions of, anterior, 575 | gustatory, 544
posterior, 573 | hemorrhoidal, inferior, 612, 642
second, 576 superior, 642
superficial, 577 hypogastric, 600
cervico-facial, 551 hypoglossal, 565
chorda tympani, 545, 549 summary of, 568
ciliary, long, 535, 536 iliac, 600
short, 536 ilio-hypogastric, 600
circumflex of arm, 554 ilio-inguinal, 600
coccygeal, divisions of, anterior, 606 incisor, 545
posterior, 575 inframaxillary, 551
of Cotunnius, 541 infra-orbital, 539
crural, anterior, 604 of facial, 551
summary of, 607 infratrochlear, 535, 530
of genito-crural, 602 intercostal, first, 593
cutaneous, of abdomen, 597 lower or abdominal, 597
calcaneo-plantar, 617 upper or pectoral, 593
external, of arm, 593 intercosto-humeral, 597
of lumbar plexus, 602 interosseous, of arm, anterior, 591
musculo-spiral, 593 posterior, 594
internal, of arm, 585 of leg, 621
small, 587 Jacobson’s, 556
musculo-spiral, 592 labial, of inferior dental, 545
of thigh, 605 of infraorbital, 539
lateral, of last dorsal, 598 lachrymal, 534
middle, of thigh, 605 laryngeal, external, 561
of obturator, 604 internal, 561
of small sciatic, 613 recurrent, 561
of thoracic, anterior, 597 lingual, of fifth, 544
lateral, 597 glosso-pharyngeal, 556
dental, anterior, 539 lumbar, divisions of, posterior, 574
interior, 545 anterior, 58
lesser inferior, 546 fifth, 607
posterior, 538 lumbo-inguinal, 603
descendens noni, 567 lumbo-sacral, 607
diaphragmatic, 578 malar, of facial, 551
digastric, 550 of orbital, 538
digital, in hand, of median, 591 masseteric, 543
of radial, 593 mastoid, 578
of ulnar, 590 maxillary, inferior, 542
in foot, external plantar, 619 summary of, 547
internal plantar, 618 superior, 533, 537
musculo-cutaneous, 620 summary of, 542
dorsal, divisions of, anterior, 593 median, 590
posterior, 574 summary of, 591
first, 593 mental, 545
of hand, 588 motor of eye, common, 528
last, 598 external, 547
of penis, 611 musculo-cutaneous of arm, 587

dorsi-lumbar, 598 leg, 619

INDEX TO VOLUME I. 687

NERVES— continued.

musculo-spiral, 592
summary of, 594
mylo-hyoid, 545
nasal, 535
external or superficial, 535
of infraorbital, 539
inferior, 540
upper, 541
of Vidian, 542
naso-palatine, 541
obturator, 602
accessory, 604
occipital (of facial), 550
great, 573
small, 578
oculo-motor, 519
cesophageal, 563
olfactory, 526
ophthalmic, 533, 534
summary of, 536
optic, 527
orbital, 537
palatine, anterior or larger, 540
external, 540
posterior or smaller, 540
palmar, of median, 591
of ulnar, 588
palpebral, 539
parotid, 543
pathetic, 519
perineal, 610
peroneal, 620
communicating, 620
petrosal, superficial, large, 542
external, 549
small, 546, 556
pharyngeal of pneumogastric, 560
of glosso-pharyngeal, 556
of spheno-palatine ganglion, 541,

542
of sympathetic, 630
phrenic, 578
plantar, cutaneous, 618
external, 619
internal, 617
pneumogastric, 556
summary of, 564
popliteal, external, 615, 619
summary of, 622
internal, 615, 616
summary of, 619
portio dura, 548
mollis, 548, 553
pterygoid, external, 543
internal, 543
pudendal, inferior, 614
pudic, 610
pulmonary, of pneumogastric, 563
radial, 593
renal, 640
respiratory, external, 583
sacral, divisions of, anterior, 608

posterior, 574
fifth, 608

Nrrves—continued.

sacral, fourth, 608
saphenous, internal, or long, 606
external, or short, 617
sciatic, great, 615
small, 613
scrotal, long, 610
spermatic, external, 602
spinal, 568. Sce NERVES, SPINAL.
accessory, 564
splanchnic, great, 635
small, 636
smallest, 636
stylo-hyoid, 550
suboccipital, 571, 575
subscapular, 584
supra-acromial, 578
supraclavicular, 578
supramaxillary, 551
supraorbital, 535
supraseapular, 553
suprasternal, 578
supratrochlear, 534
temporal, of auriculo-temporal, 544
deep, 542
of facial, 551
of orbital, 537, 538
temporo-facial, 551
malar, 537
thoracic, anterior, 584
posterior, 583
thyroid, 632
tibial, anterior, 619, 621
posterior, 617
tonsillitic, 556
trifacial, 532
trochlear, 519
tympanic, 556
ulnar, 588
summary of, 590
collateral, 592
Vidian, 541
of Wrisberg, 587

NERVES, CRANIAL, classification of, 519

connections with encephalon, 520
general distribution of, 523
first pair, or olfactory, 526
second pair, or optic, 527
third pair, 528
fourth pair, 530
fifth pair, 532
ophthalmie, 534
superior maxillary, 537
inferior maxillary, 542
sixth pair, 547
seventh pair, 548
facial, 548
auditory, 553
eighth pair, glosso-pharyngeal, 554
pheumogastric, 556
spinal accessory, 564
ninth pair, 565

NERVES, SPINAL, 568

divisions of, anterior, 575
posterior, 571

668

Nerves, SPINAL—continued,
length of, in spinal canal, 570
roots of, 569

NERVES, SYMPATHETIC,

Anatomy of, 626
ganglia of. See GANGLION
gangliated cords of, 626

cervical part, 628
lumbar part, 636
sacral part, 636
thoracic part, 633
plexuses of, 638. See PLExXusES

Nerves of abdomen, muscular, 625

of arm, cutaneous, 623
muscular, 208, 625

of back, cutaneous, 622
muscular, 624

of bladder, 642

of buttock, cutaneous, 623
muscular, 626

of eyelids and eyebrows, cutaneous,

622

muscular, 528, 530, 547, 624

of face, cutaneous, 622
muscular, 274, 624

of foot, cutaneous, 623, 624
muscular, 259, 626

of forearm, cutaneous, 623
muscular, 214, 221, 625

of hand, cutaneous, 623
muscular, 224, 626

of head, cutaneous, 622
muscular, 624

of heart, 561, 630, 632, 638

of hip, muscular, 284, 624

of larynx, 561, 624

of leg, cutaneous, 623,
muscular, 248, 255, 626

of limb, lower, cutaneous, 623
muscular, 626

upper, cutaneous, 623

muscular, 625

of lips, cutaneous, 622

of lungs, 563

of muscles of mastication, 626

of muscles between trunk and upper
limb, 192, 197, 625
of neck, cutaneous, 622
muscular, 294, 297, 624, 625

of nose, cutaneous, 622

of cesophagus, 553

of orbit, muscular, 277, 624

of ovary, 642

of palate, muscular, 290, 624

of penis, 623, 642

of perineum, cutaneous, 623
muscular, 331, 625

of pharynx, 290, 561, 624, 630

of scrotum, 623

of shoulder, cutaneous, 623
muscular, 203, 625

of thigh, cutaneous, 623
muscular, 234, 240, 243, 626

of thorax, muscular, 311, 625

of thumb muscular, 625

descriptive

INDEX TO VOLUME I,

NERVES—continued.
of tongue, 286, 624
of trunk, cutaneous, 622
muscular, 624
of uterus, 642
of vagina, 642
of vas deferens, 642
of vesicula seminalis, 642
Nervus abducens, 547
cardiacus profundus, seu magnus,
632
cardiacus superficialis, 630
ischiadicus major, 615
ischiadicus minor, 613
motor oculi externus, 547
motorius oculi, 528
oculo-nasalis, 535
patheticus, 530
renalis posterior, 636
splanchnicus supremus, 636
trigeminus, 532
trochlearis, 530
vagus (wandering nerve), 556
Neural (vetpoy, a nerve), arches of cra-
nium, 76
of vertebra, 2
canal, 10
septum, 332
spines of vertebrae, 10
Neurapophysis (vetvpov, a nerve ; apophy-
Sis), 10
Neurocentral suture, 20
Neurology (vetvpov, a nerve ; Adyos, dis-
course), 519
Norma verticalis (vertical rule), 79
Noss, arteries of, 365, 373, 377
cavities or fossie of, 65
meatus of, 46, 66
muscles of, 269
nerves of, 535, 539, 541, 542, 622
septum of, 65
veins of, 476
Notch of acetabulum, 103
of bone, 9
interclavicular, 26
intercondylar, 109
jugular, 33
sacro-sciatic, IOI, 103
scapular, 82
sigmoid, 55
supraorbital, 35
suprascapular, $3
Notches of vertebrie, 10
Nuclei of cranial nerves, 521
Nutrient artery of femur, 459
fibula, 465
humerus, 402
ilium, 448
radius, 409
tibia, 464
ulna, 409

OBLIQUE inguinal hernia, 337
muscles of eye, inferior, 277
superior, 275

INDEX TO VOLUME I, 669

Obliquus abdominis externus, 315
internus, 317
capitis, 305
Obturator (obtwro, I stop wp) artery, 442
relation to hernia, 341
fascia, 327
foramen, 100, 103
membrane or ligament, 163
muscles, 230, 231
nerve, 602
accessory, 604
Occipital (occiput, the back of the head)
angle, 79
artery, 366
bone, 31
articulations of, 137, 140
ossification of, 67
crest, 33
foramen, 31, 65
fosse, 33
groove, 39
lymphatics, 517
nerve, of facial, 550
great, 573
small, 578
protuberances, 33
ridge, 33
sinus, anterior, 484
posterior, 483
vein, 479
of diploé, 481
Occipitalis muscle, 264
Occipito-atlantal ligaments, 140
Occipito-axial ligaments, 140
Occipito-frontal aponeurosis, 264
Occipito-frontalis muscle, 264
Occipito-mastoid suture, 57
Occipito-parietal suture, 57
Oculo-motor nerve, 519
Odontoid (d5dus, gen. ddé6vTos, a tooth ;
el5os, shape) ligament, 139, 140
process of the axis, 12, 21
Csophageal arteries, 387, 420, 425
lymphatic glands, 513
nerves, 563
plexus, 563
Csophagus, foramen for in diaphragm,
B11
lymphaties of, 514
Olecranon (aAévn, the elbow ; Kpavos, a
helmet), So
fossa of, 87
Olfactory nerve, 526
Olivary process, 42
Omo-hyoid (@uos, the shoulder; hyoid
bone) muscle, 294
Ophthalmic (éP@aruds, an eye) artery,
375,
ganglion, 536
nerve, 533, 534
vein, 484
Opisthotic (dmoGev, behind; ods, gen.
ods, the ear), portion of temporal
bone, 69
Opponens muscle, thumb, 222

*

Opponens—continued,
muscle, toe, 258
Optic foramen, 44, 60, 65
nerve or tract, 527
Orbicular ligament, 150
Orbicularis oris, 271
palpebrarum, 266
Orbital arch, 35
bones, 74
foramina, 36
nerve, 537
plate of ethmoid bone, 45
process of palate bone, 59
Orbito-sphenoid bone, 74
Orbits (orbita, a circle), 59
fascie of, 278
muscles of, 275, 277
nerves passing into, 5.9
Organs and textures, I
Origin of muscles, 184
Orthognathous (6p8és, upright; yvaéos, a
jaw) skulls, 79
Os caleis, 114
articulations of, 174
homology of, 128
ossification of, 122
centrale, 128
coxee (the bone of the hip), 100
lingue, 55
mImagnum, 92
ossification of, 100
planum, 45
pubis, 102
homology of, 123
ossification of, 122
unguis, 52
Ossa suprasternalia (bones above the
sternum), 27
Ossa triquetra (triangular bones), 58
Ossa Wormii, 58, 67
Osseous (0s, a bone) tissue, 7
Ossification, 8
of bones of head, 67
of pelvis and lower limb, 1 18
of upper limb, 95
of ribs and sternum, 30
of vertebree, 19

| Osteology (daréov, a bone; Adyos, dis-

course), 7
Otic (ods, gen. wTds, the ear) ganglion,

Ovarian artery, 433
nerves, 642
plexus, 404
vein, 494

PALATAL bones, 74
Palate bone, 49
ossification of, 72
hard, 47, 49
muscles of soft, 288
plate of superior maxilla, 47
soft, 288
Palatine arteries, 364, 372, 373
canal, 48, 61

670

Palatine—continued.
foramina, 47, 48, 50, 62
nerves, 540
veins, 476, 477
Palato-glossus muscle, 289
Palato-pharyngeus muscle, 289
Palmar arches, 411, 418
ligaments, carpal, 156 |
carpo-metacarpal, 157
metacarpal, 158
nerves, of median, 591
of ulnar, 588
Palmaris muscle, brevis, 221
longus, 210
Palpebral artery, 377
nerve, 539
vein, 476
Pampiniform (pampinus, a tendril;
forma, shape), plexus, 494
Pancreas, lymphatics of, 511 |
Pancreatic artery, 428
plexus, 640
vein, 501
Pancreatico-duodenal arteries, 427, 428
Panniculus adiposus, 186
carnosus, 186, 291
Par vaguin, 556
Parapophysis (mapa, beside ; apophysis),
II, 24
Paraxial (mapa, beside; axis) muscles,

222

> 2333
Parietal bone, 34

ossification of, 68
foramen, 34
Parieto-mastoid suture, 58
Parotid fascia, 291
nerve, 543
vein, 477
Patella (a dish er plate), 110
ligament of, 167
lateral, 170
movement of én femur, 171
ossification of, 119
Patellar plexus, 607
Pathetic nerve, 519
Pectineus muscle, 241
Pectoral region, fascia of, 193
Pectoralis major muscle, 193
minor, 196
Pedicles of vertebrx, 10
Pelvic fascia, 326
girdle, 123
plexus, 641
Pelvic and thoracic limbs, homologous
bones in, 129
Pelvis (a basin), 100, 104
articulations of, 159
axis of, 106
brim of, 104
compared with shoulder, 123
differences in the sexes, 106
dimensions of, 107

distinctive characters of in man, 130 |

fascie of, 326
lower or true, 104

INDEX TO VOLUME I.

Pelvis—continued.
lymphaties of, 508
ossification of, 118
position of, 105
upper or false, 104
Penis, dorsal artery of, 447
nerve of, 611
vein of, 500
lymphatics of, 508
muscles of, 264
nerves of, 623, 625, 642
Perforans muscle, in hand, 213
in foot, 252
Perforating arteries of foot, 467, 471
of hand, 419
of thigh, 458
of thorax, 391
Perforatus muscle, of hand, 211
of foot, 256
Pericardiac arteries, 391, 420
Pericranium (mepi, about; «pavloy, the
skull), 264

Perimysium (epi, around; pis, a
muscle), 183
Perineum (7epi, about; valw, I am

situated), fascia of, 325
muscles of, 327
in female, 331
nerves of, cutaneous, 623
muscular, 331, 625
Perineal artery, superficial, 445, 447
transverse, 446
fascia, 325
nerve, 610
Periotic (rept, about; ots, gen. etds, the
ear) portion of temporal bone, 69,

od

74
Periosteum (rept, about ; doréov, a bone),

Perivascular spaces or canals, 518
Peroneal (mepsvy, the pin of a buckle,
the fibula) arteries, 464, 465

bone, 112
nerve, 620
vein, 496
Peronei muscles, 246, 248
Peroneo-calcaneus internus muscle, 254
Petro-mastoid portion of temporal bone,
69, 74
Petrosal nerves, large, 542
external, 549
small, 546, 556
sinuses, 483
Petrous (mérpa, a rock) ganglion,.555
portion of the temporal bone, 37, 39
Phalanges (pddayé, a rank of soldiers) of
fingers, 94
articulations of, 159
ossification of, 100
of toes, 117
articulations of, ESI
ossification of, 122
Pharyngeal artery, 373
nerve, of glosso-pharyngeal, 556
of pneumogastric, 560

INDEX TO VOLUME I.

Pharyngeal —continucd
nerve, of spheno-palatine ganglion,
541,542
of sympathetic, 630
plexus, 556, 560, 630
vein, 479
Pharynx (papvyé) muscles of, 286
nerves of, 624
Phrenic (¢phv, the diaphragm) artery,
inferior, 435
superior, 391
nerve, 578
vein, 494
Pia mater, lymphatics of, 518
Pillars of abdominal ring, 316
fauces, 288
Pisiform (pisum, a pea; forma, shape)
bone, 92
articulation of, 157
ossification of, 100
Pituitary (pituita, phlegm or mucus)
fossa, 42
Plane, mesial, 5, 6
Plantar (planta, the sole of the foot) ar-

teries, 465, 466
fascia, 255
muscles, 255
nerves, 617, 618, 619
Plantaris muscle, 252
Planum temporale (temporal plane), 34
Plate, mesial, of vomer, 51
orbital of frontal bone, 35
of ethmoid, 45
palate, of palate bone, 49
of superior maxilla, 47
pterygoid, internal and external,
44.
tympanic, 40
vertical of ethmoid, 45
Platysma myoides (mAdrucua, a plate, ,
from mAativw, I extend; pis, a |
muscle ; ei60s, shape), 272, 290 |
Plexus, subperitoneal arterial, 437
PLEXUSES of nerves, aortic, 640
brachial, 582
cardiac, 638
carotid, 629
cavernous, 629, 630
cervical, 577
summary of, 580
posterior, 573
ceeliac, 640
coronary, of heart, 638
of stomach, 640
cranial, 628
cystic, 640
diaphragmatic, 639
epigastric, 639
gangliosus, 641
gastro-duodenal, 640
gastro-epiploic, 640
hepatic, 640
hypogastric, 641
inferior, 641
infraorbital, 540

671

PLExusES—continued.
intermesenteric, 640
lumbar, 598
mesenteric, inferior, 641

superior, 640
cesophageal, 563
pancreatic, 640
patellar, 607
pelvic, 641
pharyngeal, 556, 560, 630
preaortic, 635
prevertebral, 687
prostatic, 642
pulmonary, 563
pyloric, 640
renal, 640
sacral, 609
solar, 639
spermatic, 640
splenic, 640
suprarenal, 639
tympanic, 556
vaginal, 642
vesical, 642

PLExvsEs of veins, choroid, 481
hemorrhoidal, 495
ovarian, 494
pampiniform, 494
prostatic, 498
pterygoid, 477
spermatic, 494
uterine, 500
vaginal, 499
vertebral, 493
vesical, 498

Pneumogastric (aveiuev, the lung ;
yaorTnp, the stomach) nerve, 556

Popliteal artery, 461
line, III
lymphatic glands, 506
nerves, 615, 616, 619
vein, 497

Popliteus muscle, 252

Portal vein, 500

Portio dura, 548
mollis, 548, 553

Postaxial (post, behind ; axis) borders of

limbs, 126

Postsphenoid bone, 70

Poupart’s ligament, 316

Preaortic plexus, 635

Preaxial (pre, before ; axis) borders of

limbs, 126

Premaxillary angle, 80
bone, 72, 74

Presphenoid bone, 70

Pressure, effects of on skull, $1

Presternum (pre, before ; stermunr), 25,

26

Prevertebral fascia, 292
muscles of neck, 296
plexus, 687

Process of bone, 8
acromion, $3
alveolar, of superior maxilla, 46

672 INDEX TO
Process—continued.
angular, of frontal hone, 36
auditory, external, 40
basilar, 31, 34
clinoid, posterior, 42
coracoid, 83
coronoid of lower jaw, 55
of ulna, 89
ensiform, 25
falciform, 162
hamular, 44
malar, 48
mastoid, 39
nasal, 48
odontoid, 12, 21
olivary, 42
orbital, of palate bone, 50
pterygoid, 42, 44
pyramidal, 50
sphenoidal, 50
spinous, of sphenoid bone, 43
styloid, of temporal bone, 40, 62
of radius, 88
of ulna, 90
supracondyloid, $7
turbinated, superior and inferior,
46
uncinate, 46
vaginal, 40
zygomatic, 38
Processes, accessory, of lumbar verte-
bree, 14, 25
mammillary, of lumbar vertebre,
15, 24
of vertebre, articular, 10, II, 12,
13, 15
spinous, 10, II, 12, 13, 14
transverse, 10, II, 12, 13, 14 |
serial relations of, 2 |
Processus cochleariformis (spoon-shaped
process), 41
Profunda artery of arm, 402
of penis, 447
of thigh, 457
Prognathous (apé, forward; vwddos, a

vs

VOLUME i.
| Pterygoid—continued.
| muscles, 279, 280
nerves, 543
plates, 44
| plexus, 477
processes, 42, 44
| Pterygoideus proprius muscle, 280
Pterygo-maxillary fissure, 60
| ligament, 272
_ Pterygo-palatine artery, 373
canal, 44, 61
Pubic arteries, 443, 452
articulation, 163
bone. See Os Pubis
portion of fascia lata, 227
Pubo-femoral ligament, 165
Pubo-urethral muscle, 331
Pubo-vesical muscle, 331%
Pudendal nerve, inferior, 614
Pudic artery, accessory, 447
external, 456
internal, 444
in female, 447
nerve, 610
vein, 496
Pulmonary artery, 345
varieties of, 350, 353
nerve of pneumogastric, 563
plexuses, 563
veins, 346
Pylorie artery, 425
plexus, 640
Pyramidal process of palate bone, 50
Pyramidalis abdominis, 322
nasi, 269
Pyriformis ( pyrws, a pear ; forma, shape)
muscle, 23
QUADRATUS femoris, 231
lumborum, 322
menti, 274
Quadriceps extensor muscle, 237

RADIAL artery, 413
varieties of, 417

jaw) skulls, 79
Promontory of sacrum, 15 |
Pronation and pronator (pronas, having

the face downward), 22:
Pronator and fexor muscles, 209
nerves of, 214 |
Pronator quadratus, 214
teres, 209
Prootic (mpd, before ; ods, gen. ads, the

ear) centre, 69

Prostatic plexus (nerves), 642
(veins), 498 |
Protuberance, occipital, external, 33 |
internal, 33
Psoas (Waa, the loin) muscles, 234, 235
Pterygoid (arrepvé, a wing ; eldos, shape)
arteries, 37
bones, 74
canal, 44

fossa, 44

nerve, 593
vein, 486
Radiated ligament, 140
Radio-carpal articulation, 154
Radio-carpalis muscle, 212
Radio-ulnar articulations, 150
Radius (a ray, or the spoke of a wheel),
87
movement of on ulna, 151
ossification of, 97
Radix longa ganglii ciliaris, 536
Ramus (a branch ; pl. rami) of ischium,
103
of lower jaw, 54
of pubie bone, 102
cervicalis princeps (art.), 366
communicans peronei (nerve), 617
tibialis (nerve), 617
descendens noni (nerve), 567
oculo-nasalis (nerve), 535

INDEX TO VOLUME I,

Ramus—continued.
superficialis vole (art.), 416
Rami intestini tenuis (art.), 428
retrogradi (art.), 418

Ranine (rana, a frog; also a swelling
under the tongue) artery, 364
vein, 476
Receptaculum chyli, 505
ganelii petrosi, 555
Recti muscles of head, anterior, 296

posterior, 305
of eye, 275
Recto-vesical fascia, 326
Rectum, lymphatics of, 511
Rectus abdominis, 320
femoris, 238
sternalis, 308
Recurrent arteries. See ARTERY
laryngeal nerve, 561
Renal (ven, the kidney) artery, 432
plexus, 640
vein, 494
Respiration, movements of, 311
Respiratory nerve, external, 583
Retinacula (restraining bands) of tendons,
186
Retrahens auriculam muscle, 265
Retzius’s classification of skulls, 79
Rhomboid (6éuBos, a rhomb, or equilateral
four-sided figure with oblique an-
gles; eldos, shape) ligaments, 146
Rhomboideus muscle, major and minor,
192
Ribs, 27
articulations of, 140
cartilages of, 29
ossification of, 30
movements of, 143
Ridge of bone, §
superciliary, 35
mylo-hyoidean, 54
occipital, 33
Ridges, condylar, 86
Ring, abdominal, external or superficial,
316
internal, or deep, 324
erural, 324
Risorius (video, I laugh) muscle, 272
Rostrum (a beak) of sphenoid bone, 42
Rotation, 133
Rotatores spine, 303
Rotula (dim. of rofa, a wheel), 110

SACRAL (sacrum) arteries, middle, 437

lateral, 449

canal, 17

cormua, 15

foramina, I5, 16

ly mphatic glands, 509

nerves, division of, anterior, 608

posterior, 574

fourth and fifth, 608

plexus, 609

vein, middle, 494

Sacro-coccygean articulation, 160

VOL. I. =

673

Sacro-coceygeus posticus muscle, 305
Sacro-iliae articulation, 161
Sacro-lumbalis muscle, 300
Sacro-sciatic foramina, 162
ligaments, 162
notches, 103
Sacro-vertebral articulation, 159
Sacrum (0s sacrum, the sacred bone
because formerly offered in sacri-
fices), 9, 15
articulations of, 160
ossification of, 21
varieties of, 17
Saddle-angle of skull, 80
Sagittal (sagitta, an arrow) suture, 58
Salpingo- phar yngeus (odAmyé, a trumpet;
pdpvyé, the pharynx) muscle, 288
Santorini’s muscle, circular, 330
risorius, 272
Saphenous (cadnvjs, manifest) nerve,
external, 617
internal, 606
opening, 495
vein, long, 495
short, 496
Sartorius (sartor, a tailor) muscle, 236
Sealene tubercle, 28
Scalenus (cadnvés, with unequal sides)
muscles, 295, 296
Seapho-cuboid articulation, 177
Scapho-cuneiform articulation, 178
Scaphoid (ckapn, a skiff or boat ;
shape) bone of foot, 115
articulation of, 175, 177
ossification of, 122
bone of hand, 91
ossification of, 100
Scapho-lunar bone, 128
Seapula, 81
compared with ilium, 124
ligaments of, 146, 145
ossification of, 95
Scapular artery, 389
notch, 82
vein, posterior, 477
Scapulo-clavicular articulation, 146
Searpa’s foramina, 48
triangle, 454
Schindylesis (cxuvdtAew, I split), 131
Sciatic (icxtoy, the hip) artery, 448
nerve, great, 615
small, 613
notches, 101, 103
Sclerotome (cxAnpds,
cut), 185
Scrotal hernia, 337
nerve, long, 610
Scrotum (a hide), ), lymphaties of, 508
nerves of, 623
Segmentation of muscles, 185
Segmented character of vertebrate skele-
ton, 3
Seements, vertebral, 5
Sella Turcica (Turkish saddle), 42
Semilunar bone, 91

eiSos,

hard; téxvw, I

x Xx

674 INDEX TO VOLUME I.

Semilunar—continued. Sinus—continwed.
bone, ossification of, 100 straight, 482
cartilages of knee, 169 tentorii, 482
cavity of radius, 88 transverse, 482, 484
ganglia of sympathetic, 639 Sinuses, air, in bones of head, 66
Semimembranosus muscle, 233 ethmoidal, 45, 67
Semispinalis muscle, 303 sphenoidal, 42, 67
Semitendinosus muscle, 23 of Valsalva, 348
Sense capsules or cavities, 76 venous, of cranium, 481
Septa, neural and hemal, 332 SKELETON (cKéAdw, I dry), 2, 7
intermuscular, of arm, 204 adapted to erect attitude, 123
foot, 256 axial, relation of bones of limbs to,
forearm, 208 122
leg, 244 SKULL, anterior region of, 58
thigh, 277 as a whole, 56
Septum (a partition, from sepio, I hedge base of, external, 61
in), crural, 341 internal, 63
narium, 65 bones of, 31
Serial homology of vertebrae, 22 difference from animals, 130

differences in from age, 77
nation, 78
sex, 78
external surface, 58
forms of, 77
irregular, 80
fossie of, 63
grooves for blood-vessels in, 65
homologies of, 73
interior of, 62
lateral region of, 60
morphology of, 73
ossification of bones of, 67
superior region of, 58

Serrated (serra, a saw) suture, 131
Serratus muscle, magnus, 196
posticus, 298
Sesamoid (cfoauov, a kind of small
grain ; eldos, shape) bones, 9
of fingers, 95
radial, 128
of toes, 117
ulnar, 127
Sexual differences in skull, 78
in pelvis, 106
in femur, 110
Sheath, crural, 227
Shin-bone, 110

Shoulder, articulation of, 148 sutures of, 56
compared with pelyis, 123 vertebrate theory of, 76
fascia of, 199 Scemmerring’s classification of cranial
ligaments of, 148 nerves, 519
muscles of, 199 Solar (so/, the sun) plexus, 639
nerves of, cutaneous, 623 | Soleus (sole, a sandal, or sole of a shoe,
muscular, 203, 625 | also a sole fish) muscle, 250
Sigmoid (G, a form of the letter ciyua, | Somatome (c@ua,a body ; téuvw, I cut), 5
sigma ; eldos, shape) artery, 432 Spermatic artery, 433
cavity of ulna, 89 cord, 336
notch, lower jaw, 55 nerve, external, 602
Sinus (a hollow) of aorta, 348 plexus (nerves), 640
basilar, 484 (veins), 494
of bone, 9 vein, 494
cavernous, 483 Sphenoid (cpny, a wedge ; eldos, shape)
nerves in, 530 bone, 41
circular, 483 ossification of, 70
esronary, of heart, 504 Sphenoidal crest, 42
falciformis inferior, 482 fissure, 44, 60, 65

superior, 482

position of nerves in, 530
frontal, 36, 67

process of palate bone, 50

of jugular vein, 479 sinus, 42, 67

lateral, 482 spongy bones, 42, 71

longitudinal, inferior, 482 Spheno-maxillary fissure, 60

longitudinal, superior, 482 fossa, 60

maxillary, 49, 67 | Spheno-palatine artery, 373

occipital, anterior, 484 foramen, 50, 61
posterior, 483 ganglion, 540

pedis, 176 Spheno-parietal, suture, 58

petrosal, inferior, 483 Sphincter (cpiyye, 1 bind) ani, external,
superior, 483 327

of portal vein, 500 | internal, 327

INDEX TO VOLUME I.

Sphineter—continued.
oris, 271
yagine, 331
Spina bifida, 22
Spine mentales, 54
Spinal accessory nerve, 564.
arteries, 383. Se¢ ARTERIES
cord, veins of, 493
nerves, 508. Sce NERVES
veins, 491
anterior longitudinal, 492
posterior longitudinal, 493
Spinalis cervicis, 305
dorsi, 301
Spine. See Vertebral Column
Spine of bone, 8
ethmoidal, 42
of ilium, anterior and posterior, 101
ischium, 103
nasal, 36, 47
neural, 10
occipital, 33
of os pubis, 103
scapula, 81, 82
tibia, 103
Spinous processes of vertebra, 10
of sphenoid bone, 43
Splanchnie nerve, great, 635
small, 636
Spleen, lymphatics of, 511
Splenic artery, 428
plexus, 640
vein, 501
Splenius (spleniwm, a pad) muscle, 299
Spongy bones, ethmoidal, 46,
inferior, 50, 53, 66, 74
sphenoidal, 42
ossification of, 71
Squamosals, 74
Squamous (sguaiue, a scale) portion of
temporal bone, 37
suture, 58, 131
Squamo-zygomatic centre, 69
Stellate ligament, 140
Stenson, foramina of, 47
Sternal artery, 391
lymphatics, 513
ribs, 27
Sternalis brutorum muscle, 308
Sterno-clavicular articulation, 146
&terno-cleido mastoid muscle, 292
Sterno-hyoid muscle, 292
Sterno-mastoid arteries, 363, 366
Sterno-thyroid muscle, 293
Sternum (crépvoy, the breast or chest),
25
ligaments of, 142
ossification of, 30
Stomach, lymphatics of, 511
Straight sinus, 482
Stratum internum circulare, 33°
Stylo-glossus muscle, 2506
Stylo-hyoid ligament, 55; 145
muscle, 283
nerve, 550

675

Styloid (o7iAos, a style or pen; eld0s,
shape) process of radius, 88
of temporal bone, 40
of ulna, 90
Stylo-mastoid artery, 367
foramen, 40, 62
Stylo-maxillary ligament, 145, 278
Stylo-pharyngeus muscle, 288
Subacromial bursa, 140
Subanconeus muscle, 207
Subclavian artery, 379
branches of, 382
surgical anatomy of, 392
varieties of, 352, 353
vein, 489
Subelavins muscle, 196
Subcostal groove, 28
muscles, 308
Subcrureus muscle, 240
Subcutaneous fascie, 186
Sublingual artery, 364
Submaxillary ganglion, 547
vein, 476
Submental artery, 365
vein, 476
Suboccipital nerve, 571, 575
Subperitoneal arterial plexus, 437
Subpubic arch, 104
fascia, 325
ligament, 163
Subscapular arteries, 389, 395
nerve, 584
vein, 489
Subscapularis fossa, 81
muscle, 203
Subscapulo-capsularis muscle, 203
Suleus of bone, 9
frontalis, 36
olfactory, 526
Superciliary ridge, 35
Superficial fascia, 186
Supination (supinus, lying on the back),
224
Supinator and extensor muscles, 215
nerves of, 220
Supinator brevis, 218
longus, 215
Supra-acromial artery, 389
nerve, 578
Supraclayicular nerve, 578
Supracondyloid process, 87
Supramaxillary nerve, 551
Supra-occipital bone, 33
Supraorbital artery, 375
foramen, 35, 59, 60
nerve, 535
vein, 476
Suprarenal capsules,
512
artery, 432
plexus, 639
vein, 494
Suprascapular artery, 387
ligament, 148
nerve, 553

lymphatics of,

676

Suprascapular—continucd.
notch, 83
vein, 477
Supraspinatus muscle, 200
Supraspinous fossa, $1
ligaments, 137
Suprasternal nerve, 578
Supratrochlear nerve, 534
Sural (sua, the calf) arteries, 462
Surgical anatomy of arteries, axillary,
399
brachial, 405
carotid, common, 360
iliac, common, 439
external, 453
internal, 453
femoral, 461
subclavian, 392
of hernia, femoral, 340
inguinal, 335
Suspensory ligament of penis, 314
Sustentaculum tali (the support of the
astragalus), 114
Sutures (stwra, a seam), forms of, 131
coronal, 57
frontal, 37
fronto-parietal, 57
interparietal, 58
lambdoidal, 57
neuro. central, 20
occipito-mastoid, 57
occipito-parietal, 57
parieto-mastoid, 58
sagittal, 58
spheno-parictal, 58
squamous, 58
temporo-parietal, 58
transverse, 58
Symmetry of form, 5
Sympathetic nerve, 626,
SYMPATHETIC
Symphysis (cvv, with, together ; ovo, I
grow) of lower jaw, 54
pubis, 102, 163
Synarthrosis (avy, with, together ; &p@pov,
a joint), 131
Synchondrosis (adv, with, together ;
x4vSpos, cartilage), sacro-iliae, 161
Syndesmo-pharyngeus muscle, 287
Synostosis (ody, with, together ; deréov, a
bone), So
Synovial burs, or sheaths, 186
of ankle, 174
of atlas, 137
of axis, 138
carpal, 157
costo-central, 140
costo-sternal, 142
of elbow-joint, 154
of flexors of fingers, 211
of hip, 166 |
of knee-joint, 170

Sce NERVE,

metacarpal, 159 |

inetatarsal, 181

tadio-carpal, 154

INDEX TO VOLUME I.

Synovial burse —continued.
radio-ulnar, 151
of ribs, 140, 142
of shoulder-joint, 150
sterno-clavicular, 146
tarsal, 176, 177
tarso-metatarsal, 180
of temporo-maxillary articulation,

ree
tibio-fibular, 173
of vertebra, articulating, 136
Systemic arteries, 346
velns, 472

TABLES of skull, 62
Tabular bones, 8
portion of occipital bone, 33
Talo-scaphoid (talus, the astragalus ;
scaphoid) ligament, 176
Talus (a die), 115. See Astragalus
Tarsal (tarsus) artery, 469
articulations, 174
Tarso-metatarsal articulations, 179
Tarsus (tepods, the upper surface of the
foot), 114
homologies of, 127
ligaments of, 174
movements of, 182
ossification of, 122
Temporal (tempora, the temples)artery, 367
anterior, 369
deep, 371
middle, 369
posterior, 369
varicties of, 369
bone, 37
ossification of, 69
fascia, 279
fossa, 60
lymphatics, 517
muscle, 279
nerve, of auriculo-temporal, 544
deep, 542
of facial, 551
of orbital, 537, 535
vein, 476
deep, 477
of diploé, 481
Temporo-facial nerve, 551
‘emporo-malar nerve, 537
Temporo-maxillary articulation, 144
vein, 475
Temporo-parietal suture, 58
Tendo Achillis (tendon of Achilles) 251
palpebrarum, 267
Tendon, central or cordiform, of dia-
phragm, 311
conjoined, of abdominal muscles, 317
Tensor palati, 290
tarsi, 267
trochlez, 27
vagine femoris, 235
Teres major, 200
minor, 201
Terms, descriptive, 6

INDEX TO VOLUME I.

Testis, lymphaties of, 512
Thenar (@évap, the palm of the hand)
prominence, 221
Thigh, bone of, 107
fascie of, 226
muscles of, anterior, 234
internal, 240
posterior, 232
nerves of, cutaneous, 623
muscular, 234, 240, 243, 626
Thoracic (thorax) aorta, 419
arteries, 395
axis, 398
duct, 504
ganglia, 633
nerves, anterior, 584
posterior, 583
veins, 489
Thorax (Oépaé, a breast-plate), 25
as a whole, 29
lymphaties of, 512, 513
muscles of, 306
Thumb, arteries of, 417
muscles of, 221
Thymic (thymus gland) arteries,
veln, 474
Thymus gland, lymphatics of, 514
Thyro-hyals, 55, 74
Thyro-hyoid muscles, 29
Thyroid artery, inferior,
superior, 361
axis, 356
foramen, 100, 103
nerves, 632
veins, 474, 479, 480
Tibia (a pipe or flute, from its supposed
resemblance), 110
homology of, 127, 129
ossification of, 119
Tibial artery, anterior, 468, 471
posterior, 463
nerve, anterior, 619, 621
posterior, 617
vein, 496
Tibialis anticus, 245
posticus, 254
secundus, 255
Tibio-fascialis anticus nvuscle, 245
Tibio-fibular articulations, 172, 173
Toe, great, muscles of, 257
Toes, bones of, 117
movements of, 182
muscles of, 256
transverse ligament of, 256
Tongue, muscles of, 284
nerves of, 286, 624
Tonsillar artery, 365
TYonsillitic nerve, 556
Torcular (a wine or oil-press) Herophili,
482
Tracheal artery, 387
Trachelo-mastoid (tpdxnaAos, the
mastoid) muscle, 300
Tract, olfactory, 526
optic, 527

391

ib
) >
3°7

«
‘

677

Transversalis fascia, 324
muscle, abdominis, 320
cervicis, 300
menti, 274
Transverse arteries. Sce ARTERY
ligament See LIGAMENT.
processes of vertebrae, 10, 24
sinus, 484
Transversus nuchee, 265
orbit, 276
Transversus pedis, 258
perinei, 329, 330, 331
Trapezium (tpameCiov, a geometrical
figure, dim. of tpdme(a, a table
or board), 192
ossification of, 100
Trapezius muscle, 187
Trapezoid bone, 92
ossification of, 100
ligament, 340
Triangle of Hesselbach, 339
Scarpa’s, 454
Triangularis oris, 274
sterni, 308
Triceps (three-headed) muscle, 206
Trifacial nerve, 532.
Trochanter (tpoxavtnp, tpoxatvw, words
unplying turning) major, 107
minor, 108
Trochanterie fossa, 107
Trochlea (rpoxiAla, a pulley) of humerus,
86

of orbit, 275
Trochlear nerve, 519
Trochlearis muscle, 275
Trunk, articulations of, 133
fascie of, anterior, 193
posterior, 187
morphology of, 332
lymphatics of, 508
muscles of, abdominal, 314
dorsal, 297
perineal, 325
thoracic, 306
morphology of, 332
nerves of, cutaneous, 622
muscular, 624.
Tuber calcis, 114
olfactorium, 526
Tubercle of bone, 8
of os caleis, 114
ribs, 28
scaphoid bone, 1:5
tibia, III
zygoma, 39
Tuberculum sell, 42
Tuberosity of bone, &
of humerus, 85
bicipital, 87
of ischium, 103
palate bone, 50
superior maxillary bone, 48
tibia, T11
Tunica abdominalis, 314
vaginalis, hernia in, 333

678 INDEX TO YOLUME I.

Turbinated (coiled, from furbo, a whirl)
bones. See Spongy bones
Tympanie (tympanum, the drum of the

ear) artery, 370
bones, 74.
nerve, 556
plate, 40, 70
ring, 69
Tympano-hyal bones, 74

ULNA (@Aevn, the elbow), 89
compared with bones of leg, 127
ossitication of, 97
Ulnar artery, 407
varieties of, 410
nerve, 588
collateral, 592
veins, 486
Umbilical artery, 440
Umbilieus, cicatrix of, 322
Unciform (wes, a hook ; forma, shape)
bone, 93
Uncinate (wneus, a hook) process of
ethmoid bone, 46
Ungual (wnguis, a nail) phalanges, 95
Ureter (otpéw, I pass urine), lymphatics
of, 512
Urethra (ovpov, urine), ligament of, tri-
angular, 325
Uterine artery, 441
plexus, 500
Uterus (womb), lymphatics of, 512
nerves of, 642
Uyula (dim. of wa), 288
muscle of, 289

VAGINA, nerves of, 642
Vaginal artery, 442
plexus, 642
process, 40
Valsalva, sinuses of, 348
Vas deferens, artery of, 440
nerves of, 642
Vasa aberrantia, brachial, 404
brevia of the stomach, arteries, 428
veins, 501
chylifera or lactea, 509
Vastus muscle, externus, 238
internus, 239
Veins, pulmonary, 346

VeINs, Systemic, Descriptive Anatomy |

of, 472
acromial thoracic, 489
alar, 489
angular, 476
auricular anterior, 477
posterior, 477
axillary, 488
azygos, 489
left or small, 491
right, 490
basilie, 487
brachial, 488
brachio-cephalie, 473
bronchial, 491

|

VeEtNS — continued.

buceal, 476
capsular, 494
cardiac, 503
great, 503
posterior, 503
small or anterior, 504
cephalic, 486
of cerebellum, 481
cerebral, 480
of choroid plexus, 481
circumflex iliac, deep, 498
superficial, 496
of shoulder, 489
coronary, of heart, 503
stomach, 501
of cranium, 48o.
cystic, 501
dental, inferior, 477
superior, 477
diaphragmatic, 474
of diploé, 485
dorsal, spinal, 492
of penis, 500
duodenal, 501
emulgent, 494
epigastric, 498
superficial, 496
facial, 475
common, 475
communicating, 477
transverse, 477
femoral, 497
frontal, 475
of diploé, 485
of Galen, 481
gastric, 501
gastro-epiploic, 501
of head and neck, 475
heart, 503
hepatic, 494
iliac, external, 498
internal, 491
common, 500
infraorbital, 476
innominate, 473
intercostal, anterior, 474
superior, 474
jugular, anterior, 479
external, 477, 489
internal, 479
jugulo-cephalic, 487
labial, 476
laryngeal, 479
lingual, 479
of lower limb and pelvis, 495
deep, 496
superficial, 495
lumbar, 494
ascending, 494
mammary, internal, 474
masseteric, 476
maxillary, internal, 477
median basilic, 487
cephalic, 487

See Sinuses.

INDEX TO VOLUME I. 679

Verns—continued. Vena—continued.
median cutaneous, 487 cava, 493
mediastinal, 474 inferior, 493
meningeal, middle, 477 opening in diaphragm for,
mental, 476 211
mesenteric, inferior. 502 varieties of, 495
superior, 501 superior, 472
nasal, 476 cordis magna, 503
occipital, 479 hemiazygos, 491
of diploé, 481 parumbilicalis, 503
ophthalmic, 484 portie, 500
ovarian, 494 tributaries of, 501
palatine, 476, 477 salvatella, 486
palpebral, inferior, 476 Vene basis vertebrarum, 492
superior, 476 comites vel satellites (companion or
pancreatic, 501 satellite veins), 488, 496
parotid, 477 cordis minim, 503
peroneal, 496 parvee, 504.
pharyngeal, 479 Galeni (veins of Galen}, 481
phrenic, 494 Venesection, caution regarding, 406
popliteal, 497 Venter (belly) of scapula, 81
portal, 500 Ventral (venter, a belly) muscles, 334
sinus of, 500 Ventro-lateral muscles, 185, 260, 333
pudic, external, 496 Ventro-inguinal (venter, the belly, cnguen,
radial cutaneous, 486 the groin) hernia, 338
ranine, 476 Vertebra dentata, 12
renal, 494 prominens, II
sacral, middle, 494 VERTEBRA, 9
saphenous, long, or internal, 495 cervical, 10
short, or external, 496 first and second, If
scapular, posterior, 477 coecygeal, 17
spermatic, 494 dorsal, 12
spinal, 491 fixed or united, 9
anterior longitudinal, 492 general characters of, 9
posterior longitudinal, 493 groups of, 10
of spinal cord, 493 homology of, 22
splenic, 501 lumbar, 13
subclavian, 489 5 movable, 9
submaxillary, 476 ( number of, 9
submental, 476 ossification of, 19
subscapular, 489 sacral, 15
supraorbital, 476 veins of bodies of, 492
suprarenal, 494 Vertebral aponeurosis, 299
suprascapular, 477 artery, 383
temporal, 476 column, 9
deep, 477 as a whole, 18
middle, 476 articulations of, 133
of diploé, 481 in child and in adult, 130
temporo-maxillary, 475 curves of, 18
thoracic, inferior and superior, 489 movements of, 137
thymic, 474 ossification of, 19
thyroid, superior, 479 veins of, 489
middle, 480 plexus, 493
inferior, 474 segments, 5
tibial, 496 Vertebrate homology, 5
ulnar, cutaneous, 486 theory of skull, 76
deep, 467 type of skeleton, 2
of upper limb, 485 Vesical arteries, 449
deep, 487 ligaments, 326
superficial, 486 plexus, nerves, 642
of vertebrae (bodies), 492 veins, 498
vertebral, 489 Vesico-prostatic artery, 440
Veins, plexuses of. See PLEXUSES Vesicula seminalis, nerves of, 642
Velum pendulum palati, 288 Vessels. See ARTERIES, VEINS, and

Vena azygos major, 491 LyMPHATICS

680 INDEX TO VOLUME I

Vidian artery, 373 | Wrist, articulation of, 154
anal, 44, 61 extension of, 225
nerve, 604 flexion of, 22

Vincula accessoria tendinum, 212 | movements of, 159

}

Vitreous (vitrwm, glass) table of skull, 62

nerves of, 588
Volar (vola, the palm of the hand)

artery, superticial, 416 XIPHISTERNUM (Eidos, a sword; orépver,
Vomer (a ploughshare), 51 the breast, 2

ossification of, 72
ZonA orbicularis, 165
WILLIS, classification of cranial nerves, | Zygapophyses (vy, root of Cedyuu, I

519 | yoke, or join together; apophysis),
circle of, 378 10, 24
Wilson’s muscle, 331 _ Zygoma (a cioss-bar, or bolt, from root
Wings of sphenoid bone, 43 | above given), 38
Wormian bones, 58 | Zygomatic arch, 60
Wrisberg, ganglion of, 638 | fossa, 60
nerve of, 387 Zygomatici muscles, 272

END OF JOLUME I

BRADBURY, AGNEW, & CO., PRINTERS, WHITEFRIARS,

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